c HO.^; E>^ 2 A UNITED STATES DEPARTMENT OF COMMERCE PUBLICATION / v\ 'Sid' 11 '* ENVIRONMENTAL CONTROL SEMINAR PROCEEDINGS U.S. DEPARTMENT OF COMMERCE Bureau of International Commerce COVER— H. E. Dr. R. J. H. Kruisinga, State Secretary for Social Affairs and Public Health, The Netherlands, addresses the Seminar in Rotterdam. U.S. Ambassador J. William Middendorf, Jr., is fourth from right, front row. ENVIRONMENTAL CONTROL SEMINAR PROCEEDINGS ROTTERDAM WARSAW BUCHAREST May 25-June 4, 1971 i w, \ a o %r ES of + U.S. DEPARTMENT OF COMMERCE Maurice H. Stans, Secretary >, BUREAU OF INTERNATIONAL COMMERCE | Harold B. Scott, Director vi September p 1971 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402. Price $2.25. FOREWORD This publication contains the papers presented during a series of seminars on water and air pollution controls conducted in Rotterdam, The Netherlands; Warsaw, Poland; and Bucharest, Romania, May 24- June 4, 1971. The United States portion of the seminar was also presented in Prague, Czechoslovakia, where the host government elected not to include papers by local experts. The seminars were presented as a part of the Trade Missions program of the Bureau of International Commerce, and the presentation in The Netherlands coincided with the visit of a U.S. Specialized Trade Mission consisting of eight U.S. businessmen engaged in the pollution control industries. The United States portion of the seminars was organized by Dr. Daniel A. Okun and Professor Arthur C. Stern, University of North Carolina, and consisted of three officials of the United States Government, three uni- versity professors, three businessmen and one official from the State of Pennsylvania. Overall planning and organization of the seminars centered in the Trade Missions Division, Robert Wilbourn, Director, and the Embassies in The Hague, Warsaw, Bucharest and Prague. Compilation of this publication was done by the Trade Missions Division. Honorable Sidney R. Galler, Deputy Assistant Secretary of Commerce for Environmental Affairs served as Seminar Director. Harold B. Scott Director Bureau of International Commerce in PREFACE These proceedings incorporate the papers presented at a series of Sem- inars on Environmental Control, with particular emphasis on technology and management of water and air pollution control, conducted in Rotterdam, Warsaw, Prague, and Bucharest under the auspices of the U.S. Department of Commerce. Originally conceived for Rotterdam by the Honorable J. William Middendorf , U.S. Ambassador to The Netherlands, the Seminars were then extended to the three other venues. The editors were asked to organize U.S. participation in these Seminars, while Mr. Merritt Freeman of the Department of Commerce, together with staff of the U.S. Embassies in the several countries, arranged for participation by the local professional organizations and experts. Special recognition must go to our Dutch, Polish and Romanian colleagues who shared the programs for the Seminars with us. In Prague, there were no formal presentations by the Czechs, although we are most appreciative of the contributions by Professors V. Madera and J. Smolik who served as moderators of the water pollution and air pollution control seminars respectively. While the papers present something of the essence of the problems and their solutions in the countries represented in these Seminars, the full value of the Seminars could only be captured by those who participated in the vigorous and significant discussions during the informal gatherings between formal sessions and following them. Urbanization and industrialization create much the same problems in all societies, and we all have much to learn from each other if we are to resolve these problems expeditiously and economically. The new hardware developed in the United States can be extremely helpful in other countries, while some of the regulatory procedures and incentives developed in Europe might well be emulated in the United States. Such seminars as these provide an excel- lent initiative for the generation of exchanges among professionals in all countries. Note should be made of the proceedings of a similar Seminar held in Bangkok in January, 1970, also under the auspices of the U.S. Department of Commerce, with a Proceedings "Water Supply and Sanitation in Developing Countries," edited by Pescod and Okun and published by the Asian Institute of Technology in Bangkok. The editors hope that these Seminars and the Proceedings will help stimulate further exchanges in the future. Daniel A. Okun Arthur C. Stern Chapel Hill, North Carolina July, 1971 IV TABLE OF CONTENTS Page Foreword iii Preface iv Environmental Management 1. The Dedication to Environmental Management 2 J. William Middendorf, American Ambassador to The Netherlands, The Hague, The Netherlands 2. Perspectives on Environmental Control Policy 5 Sidney R. Galler, Deputy Assistant Secretary for Environmental Affairs, U.S. Department of Commerce, Washington, D.C., U.S.A. 3. The International Cooperative Effort to Overcome Environmental Problems 7 H. J. de Koster, State Secretary for Foreign Affairs, The Hague, The Netherlands 4. Objectives of Environmental Management Policy in The Netherlands 12 R. J. H. Kruisinga, State Secretary for Social Affairs and Public Health, The Hague, The Netherlands 5. Rotterdam, Environment and Commerce 23 W. H. Fackema Andreae, President of the Rotterdam Chamber of Commerce, Rotterdam, The Netherlands 6. Environmental Management in Poland 25 W. Janiszewski, Vice-President of the Central Water Resources Board (CUGW) , Warsaw, Poland Water Pollution Control 7. New Directions for Water Pollution Control. 31 Daniel A. Okun, Head of the Department of Environ- mental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, U.S.A. 8. New Technology for Water Pollution Control 43 David G. Stephan, Assistant Commissioner, and John J. Convery, Special Technical Assistant, Research and Development, Water Quality Office, Environmental Protection Agency, Washington, D.C. , U.S.A. v Page 9. Incorporation of New Pollution Control Technology in Process Design and Control 79 Roy F. Weston, President, Roy F. Weston, Inc., West Chester, Pennsylvania, U.S.A. 10. Evaluation of New Water Pollution Control Technology ... 93 Walter A. Lyon, Director, Bureau of Sanitary Engineering, Pennsylvania Department of Environmental Resources, Harrisburg, Pennsylvania, U.S.A. 11. Water Pollution in The Netherlands 105 K. C. Zijlstra, Director, Netherlands Government Institute for Wastewater Treatment, Voorburg, The Netherlands 12. A Statistical Model of the Interdependence of River Flow Rate and Pollution Concentrations Ill Henryk Manczak, Director, Water Economics Research Institute, Central Water Resources Board, Warsaw, Poland 13. The Prevention and Control of Water Pollution in the Romanian Socialist Republic 128 Mihai Lazarescu, National Council of Water, and George Rusu, National Council for Science and Technology, Bucharest, Romania 14. New Planning Approaches to Water Pollution Control .... 133 Emanuel Blitz, Head of Water Supply and Sewage Chair, Civil Engineering Institute of Bucharest, Bucharest, Romania 15. Increased Efficiency of Water Treatment by Flocculants . . 137 T. Ionescu and S. Constant inescu, Ministry of Agriculture, Food Industry, Forestry, and Water, Bucharest, Romania 16. Approaches to Prevention of Water Pollution 140 Mircea Negulescu, Lidia Vaicum, Vetena Ghederim, Margareta Wlezek, Alexandru Cicei, and Angela Eminovici, Deputy Director and Staff Members, Research and Engi- neering Institute for Water Management, Bucharest, Romania Air Pollution Control 17. Air Pollution and Its Control 147 Arthur C. Stern, Professor, Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, U.S.A. VI Page 18. Establishing the Extent of Air Pollution Control Required 159 Arie Jan Haagen-Smit, Division of Biology, California Institute of Technology, Pasadena, California, U.S.A. 19. The Control of Air Pollution from Combustion Sources . . . 174 John H. Fernandes, Coordinator, Pollution Control Systems, Industrial Group, Combustion Engineering, Inc., Windsor, Connecticut, U.S.A. 20. The Control of Industrial Air Pollution 199 Allen D. Brandt, Manager, and David M. Anderson, Assistant Manager, Environmental Quality Control Division, Bethlehem Steel Corporation, Bethlehem, Pennsylvania, U.S.A. 21. The Status of Instrumentation in Air Pollution Control . . 213 Robert E. Neligan, Acting Director, Division of Applied Technology, Bureau of Stationary Source Pollution Control, Air Pollution Control Office, Environmental Protection Agency, Research Triangle Park, North Carolina, U.S.A. 22. The Effort for Clean Air in The Netherlands 234 N. J. A. Groen, Chief Public Health Officer, State Inspectorate for Public Health, Leidschendam, The Netherlands 23. Evaluation of the Present Situation and the General Trends of Activity in the Protection of the Air in Poland .... 240 Jacek Janczak, Director of Air Pollution Control Office, Central Water Resources Administration, Warsaw, Poland 24. The Impact of Atmospheric Conditions on the Propagation of Sulfur Dioxide 247 Regina Hryniewicz, State Hydrological-Meteorological Institute, Warsaw, Poland 25. Periodic Measurements of Atmospheric Pollution and Their Interpretation 261 Andrzej Kasprzycki, State Hydrological-Meteorological Institute, Warsaw, Poland 26. Dry Ammonia Process for Sulfur Oxide Neutralization. . . . 271 Romuald T. Chrusciel, Vice-Chief Coordinator for Abate- ment of Sulfur Oxides Emissions, Power Research and Testing Organization, "Energopomiar , " , Gliwice, Poland 27. Air Pollution Prevention and Control in Romania — General Aspects of the Problem 279 Matei Nicolau, Engineer, National Council for Science and Technology, Bucharest, Romania Vll Page 28. Basic Criteria of the Norms for Maximum Admissible Pollutant Concentrations in the Atmosphere of Town Areas 282 M. Barnea, Head of Laboratory, Institute of Hygiene and Public Health, Academy of Medical Sciences, Bucharest, Romania 29. The Action of Atmospheric Dust and Gas Pollutants on Infectious Processes 287 Hie Ardelean, Professor, Corresponding Member of the Academy of the Socialist Republic of Romania, Head of General Hygiene Chair, Medicine and Pharmacy Institute, Bucharest, Romania 30. Air Pollution Control on the Working Platforms of Coal Carbonization Plants 292 Matsi Nicolau, Engineer, National Council for Science and Technology, Bucharest, Romania vm ENVIRONMENTAL MANAGEMENT THE DEDICATION TO ENVIRONMENTAL MANAGEMENT By J. William Middendorf U. S. Ambassador to the Netherlands These seminars provide a forum for many of the leading experts of the Netherlands, of the United States, of Belgium, Germany and other countries, in a field which seems destined to be one of the most dramatic of the decade of the 70' s. All — whether they represent government, science or industry — must feel a deep sense of privilege. They are in the forefront of an effort to assure for generations to come the most essential of all commodities — the quality of our environment. They are in the forefront of an effort which must succeed, and which will surely succeed. As we all know, the question of the effect of human activities on the environment did not receive enough attention for too long a time. The development of industry supplied good jobs and the good things of life to hundreds of millions of persons. But it inevitably affected the air and water around us. The motor car offered essential transportation for many millions — but also at an environmental cost. It is only in the most recent years that people and governments and industry all over the world have fully realized the need to preserve and restore clean air and clean water. Now we must act on that realization. In all countries urgent programs are going forward. They involve legis- lation, sizeable research grants for scientific institutions, and large industrial projects. When such massive effort is concentrated on a problem there is reason for confidence that solutions will be found. In our striving for solutions there are, it seems to me, a number of factors which we should keep in mind. One of these is the need to resist pressures for quick solutions, and to exercise great care that the solution which we select for an individual pollution problem does not create an equal or worse problem of a different sort. I have in mind, as an example, discussions now taking place in the United States and in other countries concerning detergents which contain phosphates. Some persons have expressed the view that such detergents cause eutrophication in lakes, ponds and other bodies of still water. As a result much pressure has developed to restrict, or even ban, the use of such detergents, and to substitute soap and non-phosphate detergents. There appears to be some very interesting contrary considerations, how- ever. Some experts believe that elimination of phosphates from detergents would do little to solve the eutrophication problem. Moreover, they note that, if soap is used as a substitute, modern fabrics will not last, and that soap and its ingredients would soon be in very short supply. Some other known substitutes, on the other hand, pose serious accident hazards, especially to children. To achieve a measure of environmental improvement at such a risk is obviously not worthwhile. Another factor which deserves our careful attention is the cost and the effectiveness of our effort. Improvement of our environment is essential; it is possible; but it is not free of charge. A better environ- ment will come about as a result of a large expenditure by industries in their efforts to clean up production processes. It will come about after large budgetary expenditures by governments. Regardless of the source of the funds, a great part of the burden will ultimately be borne by the indi- vidual user of the products of our society, and by the individual taxpayer. We must take care that these funds are spent economically and wisely. The solutions which we select should be based on the most painstaking research and the most effective modern technology. The solutions should safeguard the quality of our air and water. They should also, however, safeguard the existence of our industries, the jobs of our workers, and to the extent possible the living standards of our people. Solutions which are so costly or so burdensome as to endanger the ability of our industries to remain in operation are not worthwhile. The need for international cooperation in the effort to improve our environment is clear. Environmental problems know no boundaries. Neither should the work of governments, scientists and industry to solve these problems. The United States is actively participating in cooperative pro- grams under the sponsorship of the United Nations and other international organizations. Within the framework of the Committee on the Challenges of a Modern Society of the North Atlantic Treaty Organization, we are working together with other countries to develop and produce a new kind of auto- mobile engine, which will be entirely clean. Earlier this year a very use- ful conference on this subject took place in Eindhoven, under the sponsor- ship of the Government of the Netherlands. We were keenly interested to learn of the progress made here in this field, with the development of a modern Stirling engine. The United States Government also welcomes the opportunity to take part in more informal exchanges of view, such as this seminar. We are eager to learn from the experiences of other countries. We are also ready to contri- bute the results of our experiments, and our most advanced technology. A seminar which will give specialists of this area of Europe and specialists from the United States the opportunity to compare problems, current projects existing technology and prospective technology is parti- cularly appropriate at this time. It is timely because, important new laws have recently been passed and special new governmental organizations have recently been created. As a result it is possible for the first time to concentrate all national resources and all energies sharply on the battle against air and water pollution. Our seminar is also very timely because, in this area of Europe and in the United States, closely related and promising research projects are now under way. New systems for measuring and controlling the various forms of polluting substances are under construction or in an advanced planning stage, In this connection I am following with particular interest the important projects now going forward rapidly here. One example is the new effort to purify at the source the water of the potato starch industry in northern Holland. Another is the automated network for identifying and measuring all forms of air pollution in the Netherlands, Belgium and Germany. The Rijnmond automated air pollution warning system is a Netherlands accom- plishment which is very worthy of note. Lastly, this is a good time for us to get together because a new mass industry has appeared on the international scene: the industry producing the technology and equipment necessary to give us clean water and clean air again. An industry producing anti-pollution devices has, of course, been in existence for a long time. Now, however, for the first time a mass market exists. As a result, new factories and laboratories are opening; others are undergoing sizeable expansion; and new patterns of trade and distribution are developing. I hope that this seminar will provide possibilities for discussions — both formal and informal — of the economic and commercial opportunities which arise from the creation of this new industry. I hope that representatives of European firms and organizations and their American counterparts will meet often to explore the possibilities for permanent relationships in the months and years to come. These rela- tionships should include trade in the equipment which our plants produce, licensing of our technology, and other forms of industrial cooperation. In that way we can make sure that our joint technical accomplishments to date, and the technical breakthrough which we hopefully anticipate for the nearer future, will be of earliest and most direct benefit to the population of all countries. The color green has been selected for the cover of the program for this seminar and its proceedings. It is the color of nature and of renewal. May the seminar help to take away the greys which are now disfiguring our surroundings, and restore the colors green and blue to their rightful place. PERSPECTIVES ON ENVIRONMENTAL CONTROL POLICY By Sidney R. Galler Deputy Assistant Secretary for Environmental Affairs U. S. Department of Commerce The enactment of the National Environmental Policy Act of 1969 pre- sented the people of the United States with the most comprehensive, enforce- able Federal policy for the protection of the environment and the regulation of activities impinging on the environment in our Nation's history. What is not generally recognized is that the NEPA is more than a set of policies guiding the promulgation of standards and regulations for the protection, of the physical environment. Actually, it represents a modern reaffirmation of a code of environmental ethics with which almost every sector of our national community will need to compare, evaluate, and, whenever necessary, reconcile its activities, business and industry not excepted. As in almost every instance of human endeavor, a legislated requirement to reconcile practices with ethical principles, no matter how wise and beneficial in the long term, often is accompanied by short-term social and economic readjustments, including severe social strains and economic hardships on some sectors of the community. This is certainly true during the present transitional stage of devel- opment of measures for environmental enhancement. New and more stringent standards and regulations of environmental protection are producing a number of temporary socioeconomic strains during this period of readjust- ment. They range from relatively minor inconvenience to the individual householder to rather severe economic hardships on some industries. However, our observations lead to the conclusion that the leaders of all sectors of the community in the United States recognize and accept our national environmental ethic. Certainly, the general public is irreversibly committed to receiving the benefits of environmental protection even though it does not yet possess a clear understanding of the costs involved. In the United States we are witnessing a dramatically increasing resolve and commitment on the part of business leaders, not only to comply with existing standards of environmental protection, but to take the initiative for the private sector in developing programs of environmental enhancement with socioeconomic benefits for the entire community. At present, we are confronted with a number of problems that tend to inhibit the rapid development of effective programs of environmental pro- tection. Some of these problems are readily susceptible to solutions. Others must await the acquisition of new knowledge and the development of improved and new technology. A few of the most noteworthy problems are cited: 1. The incompleteness of environmental data; 2. The inadequacy of ecological information required for the practical interpretation of environmental data; 3. Closely associated, the lack of reliable predictive ecological systems or models for estimating the kinds of probabilities of environmental impacts that could result from various kinds of proposed actions; 4. We need reliable technical-economic information planning systems for calculating the socioeconomic cost/benefits associated with options for complying with environmental standards. In addition, there are a number of secondary, but no less important, environmental issues that will have to be resolved if we are to accelerate our programs of environmental protection. 1. A need to facilitate the transfer of knowledge gained from basic ecological research to engineering application. We must improve the "translation" of the language of the ecologist so that it can be more readily interpreted by the engineer and technologist. 2. We must improve both the reliability and accuracy of environmental monitoring instruments and techniques. 3. We must discover ways of accelerating the transfer of existing technology to environmental protection. 4. Closely related, we must find ways of encouraging technological innovation to improve our systems of environmental protection and enhancement. 5. We must develop mechanisms for predicting the "downstream" envi- ronmental constraints on developing technology as part of our technology assessment apparatus. Although none of the aforementioned problems are insurmountable, their solutions will require a continuing substantial investment, both financial and scientific and technological. It is our hope that the exchanges of information and discussions associated with the environmental control seminars will be helpful in facilitating progress towards environ- mental protection with the greatest socioeconomic benefits for the entire community. THE INTERNATIONAL COOPERATIVE EFFORT TO OVERCOME ENVIRONMENTAL PROBLEMS By H. J. deKoster State Secretary for Foreign Affairs the Netherlands We all know that environmental pollution is a pressing problem, especially in the highly industrialized countries. In many cases it is only international cooperation that can offer the prospect of a final solution. We are all becoming increasingly aware that our national environment is part of an ecological equilibrium, the disturbance of which cannot continue beyond certain limits. In the relationship of mankind to his environment, the latter imposes built-in restrictions on human activity. This is a challenge to the whole of mankind that can only be met in a spirit of constructive international collaboration. It is difficult and in a way somewhat useless to draw a sharp distinc- tion between environment issues of a purely national character and those of international concern. We know from experience that in the course of time, the international extent of the pollution problem has become greater and we expect that it will continue to grow in the future. Indeed, the inter- national repercussions should be the concern of us all, whether they relate to transboundary pollution, or interregional problems of urban environment in border areas, or disruptions in the exchange of products and the free flow of resources. As in respect of many other urgent issues, we should develop an international consciousness also in environmental affairs. It is generally appreciated that environmental issues, as they present themselves today, can broadly be ascribed to such factors as population growth, the advance of technology and expanding consumer requirements. At an earlier stage in our industrial development, we attach such great value to these factors, as being the chief guideposts of our economy, that we almost took our environment for granted. Our social ethics seemed to be that nature was subordinate to man. And economic theory had led us to believe that the resources of our environment were free of charge. Only recently, here in Holland in the sixties, did people begin to recognize the importance of such "trivial" matters as clean air and clean water, and the need for more recreational facilities and better living conditions in general. Basic material needs were increasingly satisfied, and consumer preferences moved on to "higher" levels — in more than one sense Even more important, there has been an increasing awareness that ultimately our very survival is at stake. Our society awakened to the fact that our environmental assets were becoming scarce and were therefore becoming ever more valuable. Man became aware that he was not situated above or outside nature; he was part of it. We are entering a new phase in which governments accept the conse- quences of an agonizing reappraisal of the value of environment to mankind. We are in the process of devising systems of legislation that will enable us to face up the challenge of environmental pollution. The new laws are no longer designed merely to prevent or remove the causes of sporadic pollution, as were the old regulations, but to ensure the purity and the health-giving properties of man's environment by deliberate and systematic action. At the same time the nations are rapidly joining forces to meet the emergency and for various reasons: 1. In the highly industrialized countries the protection of the environment is becoming a matter of the greatest urgency and governments are spontaneously looking for international support for their national efforts. We have had recourse to international cooperation for many years in our attempts to solve many other problems — our security, the needs of developing countries, matters of trade policy and monetary difficulties. It seems to me quite obvious that we should now endeavor to cooperate internationally in matters of environmental control, if only to gain a better understanding of all the problems. By consulting each other, by exchanging information and by doing research work together we can find remedies for the ills that afflict our environment. 2. A second, more specific argument in favor of international consul- tation on the environment is that environmental pollution does not stop at national boundaries; indeed, a particularly frightening aspect of pollution is that it can affect the entire globe. Take the pollution of the oceans and the contamination of the tropo- sphere and stratosphere by subsonic and supersonic aircraft. Regional trans -boundary pollution — affecting a few countries only— is also becoming an increasingly serious matter. Trans-boundary pollution problems call for effective forms of bilateral and multi- lateral cooperation with regard to such questions as water manage- ment, urbanization, industrialization and nature conservation, especially, though not only, in the frontier areas. 3. A third reason why environmental problems are being tackled inter- nationally is that international trade may suffer as a result of pollution of the environment. It has been found that in some countries products may be required to satisfy such norms as would constitute additional non-tariff barriers to international trade. (Take for instance, the plans for legislation on pesticides drawn up in the United States Congress a short time ago, plans subse- quently discussed during a conference of the Organization for Economic Cooperation and Development. I hope that the United States Government and Congress has heeded the critical views expressed by the experts attending that Conference) . This poses the question as to the extent to which products standards (includ- ing design standards) should be harmonized internationally. Dr. Harold Passer, Assistant Secretary of Commerce for Economic Affairs, made some pertinent remarks in a speech on 26th April; he asked whether, within the United States, national or local (i.e. State) standards should be adopted: "One of the basic issues still to be completely resolved is the question of uniform national pollution standards versus varying local or state standards... In many cases the overriding consid- eration dictating a need for uniform national standards is the effect that conflicting local standards would have on the nation- wide market systems of many firms and industries. A producer of detergents could not make and market at reasonable cost a product that must satisfy hundreds of conflicting local standards. Like- wise, automobile manufacturers could not design and produce, at reasonable cost, emission controls for cars that would satisfy conflicting State or local standards" . These arguments in favor of uniform standards within the United States are equally cogent in the international context. We shall have to make efforts internationally to harmonize our standards for products as much as we can, though some of our environmental problems may become so pressing that we shall not always be able to wait until international agreement has been arrived at before laying down national legislation. Fourthly — there are other standards and norms besides those for products that should be set internationally. Consultations are in progress in such organizations as WHO and FAO on the harmoni- zation of criteria, guides and standards in respect of the envir- onmental factors themselves. Then there are the standards for the disposal of effluents as they enter the environment during the production process, i.e. regu- lations not directly related to the product proper, standards that trade and industry will have to satisfy — they should also be made the subject of international consultation. It should, in principle, be possible for emission standards in the various countries to differ. However, bilateral or multilateral regulations are a sine qua non where industries are located in frontier areas or contam- inate international rivers or waters. In such contingencies efforts must be made to reach very specific agreement on the over- all pollution that is nationally or regionally permissible. These matters are vital to the Netherlands, lying as it does in the delta of Western Europe: the equivalent of 250 kilograms of kit- chen salt comes down the Rhine every second; intensive internation- al discussions are taking place on the subject. All the same, there will have to be a certain amount of latitude for individual countries where such is possible without harming neighboring countries or upsetting the ecological equilibrium. Every nation will take its political decisions within those limits. Those decisions reflect the value a nation attaches to the quality of the environmental factors for its well-being. They determine the price the producer (and, of course, ultimately the consumer) must pay for the use of the environment. Lastly, it is important to ensure that the views of governments are harmonized in respect of the allocation of the cost of envir- onmental management within their national economies. Of course, this is also a matter that concerns enterprises that have to compete in international markets. The Netherlands believes that, in principle, the polluter should pay, that as a rule enterprises themselves should bear the cost of complying with any new regu- lations. If the enterprises in competing countries have to satisfy less stringent requirements, this may as a rule not prompt govern- ments to give financial support or protection to industries which have to comply with more stringent requirements. The advantage inherent in the principle that the cost of environ- mental management should wherever possible be made to appear on the industries' own cost-price accounts is that this ensures that resources are allocated with optimum effect. It also fosters the development of cheaper and cleaner methods of production. The principle that as much as possible of the cost should be borne by the producer could be put into practice by introducing coercive regulations such as standards (i.e. preventive measures) or by imposing levies on enterprises. In the latter case the receipts would be used to rectify damage to the environment or to create alternative environmental facilities. A useful discussion on such issues has already begun in the Organization for Economic Coop- eration and Development. An important question is, of course, what economic impact all these measures would have. This would depend essentially on how technology meets the new environmental challenge. It would be a great advantage if new industrial technologies, including the recycling of waste, could in the long run compensate for the short-term effects of cost increases. At all events, a new orientation of our economic structure, both by sector and region, should certainly be expected as a result of our environmental activities. The work of international organizations: the European governments are cooperating in a number of international organizations in matters of environmental management. A few of them will be mentioned. One is the Council of Europe, which plays a vital part in nature conservation and which can also do much in the sphere of legislation. Trans-boundary pollution problems affecting both East and West are discussed in the ECE; for example, the symposium held in Prague in May, 1971. There will have to be far-reaching "environmental integration" within the expanded European Community. We are also cooperating in matters of environmental management in the narrower context of Benelux. In other organizations we have the privilege of working together with the United States. It appears that in the United States environmental problems are being tackled most energetically and with great perspicacity. We should be able to benefit by the experience gained by our American friends as we cooperate with them in various international organizations, such as the Organization for Economic Cooperation and Development, in which among other subjects the economic and trade policy aspects of environmental pollution are discussed. This cooperation between countries that have much 10 in common, as regards both their economic systems and, alas, their poten- tialities as pollutors, will hopefully prove successful. Then again, we are cooperating in the United Nations family. WHO, FAO and other organi- zations are doing most important expert work. In June 1972 there will be a noteworthy event — the United Nations Conference in Stockholm. At this Conference problems of environmental control are to be dealt with in close cooperation with developing countries. However, we should not lose sight of the fact that many of these countries look upon the problems with mixed feelings. They do not know whether or not the combatting of pollution in developed countries will be to their disadvantage since it is bound to make industrial products more expensive. They do not know whether or not envir- onmental rules may hamper their basic economic development. Yet the interests of developing countries are also at stake. I believe a recent report on pollution in metropolitan areas contended that the most polluted cities in the world are Seoul, Taipei, Ankara, Mexico City and Buenos Aires, in that order. Last but not least, there is NATO, within which a number of pilot pro- jects have been launched, the initiative having been taken by the United States. A conference on "clean" internal combustion engines was held recently at Eindhoven under the auspices of NATO. The rapid expansion of international cooperation in recent times also unfortunately has disadvan- tages, not only for travel-weary officials. Experts are few and far between; they have to divide their attention, because they have to attend too many meetings. If only for this reason, we should constantly endeavor to achieve optimum efficiency in the division of labor over the various international organizations. The environment is such a vital matter, however, that we shall have to be patient as we pass through the initial stages and give the organizations a chance gradually to achieve an efficient division of labor. Finally both science and industry have a vital part to play in the solution of our environmental problems. It is their task to make it tech- nically possible to combat environmental pollution and to do so at reason- able cost. It is to science and industry that the authorities look, as also to the citizens and the consumer, for support in the implementation of their policies. May the seminar be a great success; may constructive discussions serve to clear the air, both figuratively and literally, and give us clean water to drink and a clean world to live in. 11 OBJECTIVES OF ENVIRONMENTAL MANAGEMENT POLICY IN THE NETHERLANDS By R. J. H. Kruisinga State Secretary for Social Affairs and Public Health The exposure of man to an increasing number of complex environmental factors, many of which are hazardous, requires the re-examination of envi- ronmental control programs and policies. Man's health is main concern of nations in their endeavour to restore the quality of man's environment. Changing Emphasis Basic sanitary programs for the prevention of communicable diseases were given highest priority during the early decades of environmental health activities. This approval is still valid today, anywhere and at any time, and continues to be the safeguard against the spread of epidemics. The application of modern technology and the subsequent economic growth have given rise to new environmental pollutants discharged with wastes from industrial processes, pesticides, chemicals added to food during production and processing and chemicals in households. The pollution of air, water, soil and food is aggravated by our ways of life in large metropolitan agglomerations and associated stress, such as crowding, noise, radiation, transport and accidents, and occupational risks. A new ecological view of human health is emerging, which emphasizes the inter-dependence of health and environmental conditions and their control. We are in a stage of technological development where the need to give "due consideration to the effect of water, soil and food and air pollution, noise and other environmental factors harmful to human health should be stressed, and where the need for the establishment of environmental health criteria and guidelines for preventive measures, and methods of determining priorities and allocating resources based on health needs is urgent." Scope of Environmental Health Programs A program in environmental health should reflect both the continuing need for the essential sanitary measures and for response to new and adverse environmental factors and conditions. Specifically: 1. Basic sanitary measures in urban and rural areas — The objective of this part of a program is the provision of essential environmental sanitation in rural and urban situations, to prevent and control communicable di- seases and promote mental and social well-being. This is accomplished by the provision of water supplies, sanitary disposal of excreta and sewage, provision of housing satisfying basic conditions of hygiene, community sanitation including food sanitation and vector control, and other means essential for the general physical and social conditions of life which are also a pre-requisite of improved health. 12 2. Control of environmental pollution and other hazards — This part of a program should aim at the reduction of air, water, land and food pollu- tion and of physical hazards such as noise and radiation to levels which permit optimal economic development without creating hazards to health or significant disturbances in the ecosystems. This has to be accomplished by establishing national and interna- tional environmental monitoring systems, adopting environmental quality criteria and standards, applying appropriate technological, legal , admin- istrative and other control measures, introducing changes in industrial, agricultural and transport technology, and initiating research programs into the effects of pollutants, their behavior in the environment and into the methods of reduction and treatment of waste products of man's activities. 3. Urban-industrial environmental health — This should aim at optimal envi- ronmental conditions in urban-industrial areas and prevent or control of the harmful effects of urbanization and industrialization. It should ensure maximum benefits for the health of the people r This will include an appraisal of the hygienic conditions of housing, of the health implications of urban, metropolitan and regional develop- ment, health implications of land use, health implications of transport systems and of work conditions. It should include the establishment of quality criteria for the urban-industrial environment including trans- port systems. It should include incorporation of health considerations into the processes for urban- industrial and neighborhood development and the initiation of research on health risks associated with life in urban areas. 4. Planning, infrastructure and institutions for environmental health pro- grams — This should create an infrastructure and institutions capable of conducting effective planning and management of environmental health programs and of integrating these into national or regional health and general development programs and policies. This has to include the assessment of the environmental health situation, the application of planning models to environmental health, including consideration of economic implications. It must consider the training, mobilization and effective utilization of human resources to meet the local and national needs. And it should pay due attention to appropriate legislation both national and international. The establish- ment of applied research institutions in the field of environmental health should thereby be considered. Nowhere in the world is it possible today to limit environmental health programs respectively to the provision of basic sanitary measures or the prevention of environmental pollution only. Most countries are faced with several or all of the environmental problems. An appraisal of each situation will disclose which problems are particularly criti- cal to a given country at a given time. Need for Greater Efforts in the Above-Mentioned Areas Work in environmental health will need to extend into all four areas referred to above, and produce four distinctly different outputs for each 13 of them. Specifically: 1. Information — This will include the generation and verification of reli- able technical information inputs on the levels of adverse or beneficial environmental conditions and factors, and environmental needs and pro- grams and effects of environmental conditions. This should be done to- gether with the development of methods and instrumentation for the gen- eration of valid information as well as the institutional arrangements required. It means the development and testing of indicators and para- meters suitable for evaluation, control and epidemiological research relative to environmental factors and conditions. This has to be a co-operative effort of the different countries based on Collaborating Institutions in environmental health. 2. Environmental health criteria — They include quality criteria for air, water, food, land and soil. They include acceptable levels of environ- mental radiation and noise and other physical factors. They include also criteria for environmental exposure; minimal requirements for the quality of housing and neighborhood, including recreational facilities. The bases for the establishment of environmental health criteria should be (1) direct effects on health, where known, (2) the desire to keep adverse exposure at minimal levels where effects cannot yet be demonstrated, (3) the public demand for the maintenance of a high qual- ity environment taking into account environmental changes and effects which may indirectly affect man's health. The setting up of environmental health criteria will involve the examination and evaluation of national criteria standards for environ- mental health. It will also involve the critical appraisal of the evi- dence of the effects on health and the environment. 3. Guidelines for environmental improvement and control — This output should provide practical guidelines and codes of good practice for planning of environmental health programs and their implementation including tech- nology. It should provide legislation, administrative and intitutional requirements, and the training of manpower, both for basic sanitary measures and environmental quality management. They should be based on an appraisal and evaluation of information and technology existing in some parts of the world, and of the needs existing in others. Field and pilot studies and supplementary research should be initiated in this respect. Priorities in the Environmental Health Program As noted earlier, in the past the work in environmental health has focused on the introduction of basic sanitary measures in urban and rural areas as a means of controlling communicable diseases, and has been focused on creating institutional agencies for environmental health, with nuclei of human resources. A shift of emphasis, outlined above, should now take place, with re-orientation of programs and re-establishment of priorities. Information, environmental health criteria and guidelines, together with methodology for environmental health planning and allocating resources based on health needs are instruments for priority decisions and should be devel- oped. 14 Parallel to this, environmental pollution and other environmental fac- tors harmful to human health should be part of a program, complementary to the provision of the basic sanitary services. This re-definition of programs and outputs fully reflects existing conditions in the human environment. It will be necessary to revise the priority objectives and to include such ad- ditional priority items that are needed in view of the changing conditions of the human environment. These may include: (1) an increased emphasis on the provision of fa- cilities for the sanitary disposal of wastes; (2) steps towards establish- ment and operation of a specified number of stations for the monitoring of adverse environmental parameters together with the necessary institutional arrangements; (3) preparatory steps, especially legislative and institu- tional, for the prevention of environmental pollution and other hazards at the local, regional, national and international level, as applicable; (4) creation of an environmental health infrastructure and institutions capable of planning and conducting environmental health programs by the end of the decade; (5) creation, or strengthening, of a specified number of training institutions for specfied human resources for environmental health. A Code of Environmental Health has to be established. One of the pur- poses of a code of environmental health should be to indicate the sequence of stages through which environmental health programs may evolve, such as the control of communicable diseases, the provision of adequate water, the sanitary disposal of waste, the sanitary handling and storage of food, oc- cupational health, housing and other problems of urbanization, the preven- tion of air, water and soil pollution, noise control and others. One of the purposes of this code also should be the development of guidelines standards and criteria for those many new environmental factors that have an adverse side-effect on the health of mankind and the health of the environment. An Historical Perspective of the Human Environment If we look back at the last century and gaze forward towards the ap- proaching decades that already mean the end of a following century, and while so doing try to consider the interaction of social development and the development of health, we come up against a remarkable and disturbing paradox. It is striking how, in the second half of the last century, health control measures, with a particularly limited knowledge of causal mecha- nisms and a minimal understanding of human physiology, nevertheless managed to achieve great successes in the control of the then prevailing endemic diseases and plagues threatening health. We need think only of smallpox, of cholera and typhoid, and of rickets and endemic malar ia--which was so greatly feared that the reclamation of one of the Dutch lakes the Haarlem- mermeer was nearly abandoned because of it. While medicine today has a detailed and often thorough knowledge of the causes of the endemic diseases of the present time — cardiac and vascular diseases, cancer and also neurosis — and though we moreover have at our dis- posal a technical and therapeutic arsenal such as never before, we still have not so far proved capable of halting the growing depradations of these diseases in society. 15 Of course we are aware of the great importance of modern therapeutic possibilities for the treatment of the individual patient, of which we cer- tainly may be proud. It is however a chilling paradox that a century ago, with such little knowledge, so much could be done about the endemic diseases then threatening society whereas now, with our much more thorough knowledge and better equipped science, the health problems threatening the community are growing to a serious degree. The technical development of health care and medical science makes large investments necessary, also so as to be able to apply the many new and important discoveries in health care. The total level of investments in health care has greatly risen in recent years. There is an unprecedentedly high level of material investments in health care. Yet, for all that a num- ber of health indicators are tending towards worse figures than in the Fifties, a tendency which is general especially in countries with a high and still rising national income. It seems a paradox. Is it? There is another apparent paradox. Man's health in the second half of the 20th century is threatened in the first place by increasing prosperity, or rather by an increase of the level by which the prosperity of a nation is still measured today; national income, national product and other economic indicators still in use. The further life expectancy of males, which with other health indicators had regularly risen until the year 1950 under the influence of better medical care and better hygienic conditions, now displays a clearly declining trend notably for males aged 30 and males aged 45. It has to be admitted that, despite the enormous increase in medical possibilities, it has not proved possible to call a halt to this phenomenon. Until recently it was still true to say that the harmful secondary effects of the so-called growing economic prosperity had not come to light. New pos- sibilities created by the technological medical revolution outweighed these negative effects. This phase is now past. Drawbacks to the Growth of Prosperity The positive technological development of health care is unable any longer to make so large a contribution to the improvement of the Dutch people's state of health as to outweigh the harmful secondary effects of economic growth on that state of health. These harmful effects cover a wide field: Every year we number in thousands the victims of road accidents. Every year in Europe there are now more than 150 thousand deaths — not only from lung cancer but also from heart disease — caused by the increase in cigarette-smoking. A growth in venereal disease, both syphilis and gonorrhoea, may be noted throughout practically the whole of Europe. Every year drugs in all their various forms are claiming more vic- tims, especially young people. In most European countries the number of young people who have to be admitted to psychiatric hospitals is on the in- crease. For the age group of 20 to 24 years hospitalization on account of alchololism and drugs is particularly disturbing in European countries. In a few countries about 25% of the admissions to psychiatric hospitals in this age group were caused by abuse of drugs and alcohol. The effects on our physical health of numerous physiologically active 16 substances present in the environment deserve our full attention in the next decade. These substances doubtless have their influence on the biochemical processes going on in the human body. On the one hand we know of many sub- stances which, used as medicine, foster health. On the other hand we are threatened by substances unintentionally present in the environment that we must characterize as pollution. Three examples from among many: 1. The concentrations of chlorinated hydrocarbons found in mother's milk for babies, persistent pesticides administered about the acceptable dose. 2. The direct introduction into the external environment of mercury com- pounds via use. In this country between 3,000 and 4,500 grams per square kilometer of pesticides containing mercury are used every year. The av- erage annual influx of mercury into The Netherlands via the water of the Rhine is about 100 tons, or an average of some 274 kilograms per day. The investigations into the effect of mercury on human health in Japan are in no way reassuring. 3. Chemical mutagens in the human environment to which an increasingly im- portant role must be assigned. Hereditary defects are coming increas- ingly to the fore, comparatively speaking. In fact this means a rela- tive increase in the number of cases of illness and mortality that may be attributed to mutations. For instance, at least 2 to 4% of live-born children are characterized by a hereditary disease or defect. Mutations have been a natural occurrence since life first appeared on earth. Only during the last forty years has it become known that mutations can also be caused artificially. This was first discovered for X-radiation and other radiations released in radioactivity. Not until after the Second World War did it come to light that chemical substances too can cause such far-reaching transmis- sible effects in genetic material. These changes in hereditary material are of a dual nature — mutations, that is to say changes in the individual genes that are not microscopi- cally visible, and breaks in the chromosomes that may give rise to chromosomal defects. Common to both is that they have mainly adverse effects of future gener- ations inheriting them. For this reason an increase in the number of mutations and chromosomal defects as a result of these substances has serious consequences for the physical and mental well-being of these generations living after us. Nor have been mentioned the still inadequately investigated consequences of numerous measures affecting the mental and physical health of people, such as housing, for example. Recently attention was drawn--rightly so — to high-rise blocks of flats as a source of mental traumas on account of the lack of freedom, the nuisance from noise and the loneliness. Those are a number of aspects of the other side — the health side — of the coin called prosperity. This does not represent a cheerful picture of health for the future! 17 A comparison with the 19th century, with the start of the Industrial Revolution, now imposes itself on us. A look back teaches us that the fac- tors that were inherent in the new conditions of life, such as developed as a result of that Industrial Revolution, led to a marked decline in the state of health during the 19th century (malnutrition, alcoholism, contagious di- seases, tuberculosis). The same countries only gradually managed to over- come the consequences of economic development in the sense that they pro- ceeded to create for man the hygienic conditions required in order to make a real adjustment to the changed conditions of life. But, at the very moment when the solution seemed within reach, other problems loomed up, problems that are now the consequence of another set of new and changed economic conditions, entailing environmental pollution, poi- sonous industrial waste, exhaust gases of motor vehicles and "unhealthy" ways of life. And so we are once again confronted with major problems of health, as for instance those in the field of cardiac and vascular disease, cancer, mental and nervous diseases, which are bound up with the ability of the population to adjust to new changes in conditions of life. Huizinga, a great Dutch cultural philosopher, clearly saw the coming sufferings of the present time in his "Shadows of Tomorrow" and analyzed essential elements leading to these phenomena of crisis. In what he calls "a diagnosis of the spiritual suffering of our day" he states the following: "If we consider the economic and the political processes of disturbance together, then, looking at their gradual progress, it would seem to amount to the fact that for more than a century now the control of means has achieved a degree of perfection at which the social forces, not regulated and combined by a principle transcending the aims of each of these forces in itself, all operate for themselves with an excess of individual purposiveness that is injurious to the harmony of the organism in its totality . " Huizinga is referring here to the means of mechanical production and technology in general, of working, of publicity, of mobilization of the masses by political or other organizations. If the development of each of these means or forces is considered in itself, the concept progress may be applied to each individual aspect. All have grown tremendously in power. Only nineteenth-century optimism could attach to the geometric concept progress the simple meaning "the bigger the better." However, starting from our present knowledge questions like the following arise: What will be the motives that will guide society in its future act ions? What will be the incentives determining the steps taken by society? On what spiritual foundation, which will be needed more than ever before, will that society be based? From what source will society derive its inspiration, and what will be the touchstone for its actions ? What is the point of departure of those actions ? What are the points of departure that will form the criteria for statutory regulations in that society? If we now conclude that the results of scientific and technological development, for whatsoever reason, have still found insufficient applica- tion in the field of health, we have to admit that we have not yet been able to apply scientific and technological development in a balanced fashion 18 to further man's well-being and the well-being of his environment. An exact inventory will have to be made of the factors that are impor- tant to the level of health of man and of his environment. The significance of those factors for physical and mental health will have to be established. In this field there is still a great deficiency of knowledge of the relevant facts and relations. Great activity to find those facts and relations is absolutely necessary. In particular the influences that can make themselves felt over longer periods will call for attention. It will also mean paying greater heed to the development of the epidemiology of non-contagious di- seases and symptons of social well-being and social illnesses. In addition, integrated planning is necessary . After all, for the future planning of health of the environment and of the human being is of the greatest importance. In any case, in this context we whall have to admit that planning in the field of environmental hygiene has not yet been adequately integrated in the planning of economic development as a whole. For a basic national policy this will in the future be an essential condition. That at this moment we see nowhere this integration of the health and social planning „ with the economic planning is to a considerable extent the result of the too isolated approach of those concerned with economic planning. Many are still too much under the influence of old theoretical ideas and trends and of partly outmoded economic approaches. In itself, this situation is not surprising. Economic analysis, which still forms the basis for what is called welfare policy, is still mainly based on the study of phenomena with regard to prices and market situation. The value of services to the health of the population and the mainte- nance of the environment in which we live is still often regarded simply as a negative element in the acquisition of prosperity. In joint responsibil- ity we are faced now with the important and stimulating task of developing the chapter of economics and politics in the service of man's health and of a healthy environment. If we are not to lose our gains in the field of the health of the people and its environment, further-reaching and also new measures will have to be taken to maintain an acceptable situation. Regulating mechanisms required to counter environmental pollution . All resources will have to be applied in the most efficient and effective way possible in the service of man and the environment in which he lives. This means that control mechanisms have to be incorporated in what is going on in society to further the improvement of the environment in which we live. In- vestigations should further be made to establish which mechanisms tend to ruin that environment. That means the introduction of more and of new in- struments to further prosperity by controlling pollution, also in a psycho- hygienic respect. It will be our joint responsibility to ensure that during a specified period the means and objectives of our society are combined into a rational pattern. The economic aspects of health care and environmental hygiene — to a certain extent they supplement one another — are difficult to establish, as long as we confine ourselves to the traditional categories of consumption, saving and investment. In other words as long as we adhere to a distinction between what is said to be consumed and what is not. Social development is partly — indeed very largely — assured by the maintenance and improvement of the population's level of health, and not only by the consumption of more goods. 19 Too little attention has been paid up to now to Alfred Marshall's view that among other things food is both an intermediate product and a consumer good. In the same way we can also place expenditure for the maintenance of a healthy environment and of healthy people in the category of productive consumption. And that is done, consciously, or unconsciously, but rightly, in a number of recent publications by authors who assume that expenditure in the field of health care and environmental hygiene relates to what may be called "human capital." Within this framework expenditures on health care and environmental hygiene may be regarded as an investment. It is appropriate to go somewhat further into the approach of the present method of quantifying national income in relation to what I have called the bill for the damage done by production activities in our society. Quite wrongly, the bill that has to be footed by health care and environ- mental hygiene has so far been entirely ignored when considering this prob- lem. If establishing a major industrial concern somewhere renders invest- ments necessary in, for instance, the water treatment sector, then ulti- mately those activities are even included in the total contribution of that establishment to national income. In the final account they are jointly presented to us as contributions towards economic growth, quantified as a rise in national income. The increase in national income calculated in this way is misleading and incorrect as an index, an indicator for the growth in prosperity. To derive an undistorted picture of the consequences which establishing that form has for prosperity, the investments for water treatment ought after all to be deducted from the contribution that this establishment makes to economic growth. And that is quite apart from other question marks that may be placed behind the unnuanced use of national income as an index to pros- perity. For that reason future social and technological development will make it necessary to apply a more gradated economic planning than that to which we have been accustomed to in the past. For otherwise in the future a steadily growing tension will come into being between what is regarded as economically desirable and what is neces- sary from the point of view of health care and environmental hygiene. From the angle of our joint responsibility it may be asked whether it is not be- coming high time at least to complement thinking in terms of purely economic growth by thinking that is explicitly directed towards the achievement of a healthy people and a healthy environment. In that view, for instance in a decision about investment, not only the effects of this on the firm in ques- tion ought to play a part, but also the hygienic and social implications. The studying and solution of those problems will be of great influence on our future welfare policy. Industrialization provides greater production, but from this we have to subtract the damaging side-effects, the negative side-effects from the in- dustrial productivity as such. And we have also to pay for these effects. This will have to influence our price mechanism. The price mechanism now does not function in a proper way. As long as we do not charge pollution products their full price in as far as they do damage to environments, we are subsidizing those products. We are then pro- moting production of these products and discouraging production of non- polluting products. With this price mechanism we have an inbuilt katalyzer for polluting the environment. 20 The solution of the two point just mentioned: (1) correction of our national production figure with the costs of eco- nomic growth and (2) correction of our price mechanism in order that the real full price is paid for polluting products and polluting processes is absolutely essential for solving our environmental pollution problems. Conclusion We live in strange times. Our prosperity is regularly incresing from year to year. That seems a paradox. But is it? What do we really mean by prosperity when we note the annual increase in prosperity? It may be asked whether a standard of living expressed in terms of money may be the goal and the universal criterion of human well- being. In the last hundred years the consumption of industrial products has increased hundredfold. What more do we want? Yes what more do we want? May prosperity, may well-being not be more than economism? Is prosper- ity, is well-being not more than stepping up the total figure of productiv- ity? That is certainly the case; of course it is so; practically non-one will deny that. And yet it is the material quantitative approach that I have outlined which for decades now has dominated the view of society throughout the world and still dominates it today, in the west and the east, the north and the south. It is only very recently that authoritative figures have dared to raise their voices against this: Kenneth Galbraith in his Liberal Hour , Rachel Carson in her Silent Spring , Ernest Zahn in his Leven met de Welvaart , Gunther Schwab in his Tanz mit dem Teufel and Mishan in his Costs of Eco- nomic Growth. It is only a very short time ago that Galbraith ventured to point to what he called our short-sighted preoccupation with production and material investments that distracts our attention from the much more urgent question of how we use our resources and above all direct them to the greater need for and possibilities of investment in man. It was not until 1963 that Rachel Carson wrote her Silent Spring, in which she asked what we are doing with "our" earth. She pointed out, for the first time in world history, that everyone is exposed to unknown chemi- cal substances, synthetic substances so thoroughly distributed over the animate and inanimate world that they occur practically everywhere, in sub- terranean streams that flow unseen beneath the earth and in the fat of penguins at the South Pole. It was even more recently, in 1967, that Mishan published his book en- titled "The Costs of Economic Growth," in which he discusses the no-choice myth with regard to the balance of payments and in which he asks the rhetor- ical question whether it is not becoming time for us to start thinking about directing our one-sided, quantitatively oriented policy of economic growth towards a more selective policy aimed at furthering human prosperity and 21 human well-being. One does not have to be a prophet to predict that these are voices which will multiply in the future and sound ever louder. These are also voices that regard healthy people in a healthy environ- ment as one of the main aims and not as one of the secondary objectives of a financial, economic, tax, welfare or well-being policy. Certainly for small, densely populated and highly industrialized coun- tries like The Netherlands, international cooperation in this very field is vital. In The Netherlands at the delta of the large European rivers, with the largest harbors in the world, the largest refinery concentration, the most densely populated area, there the problems of this type will let themselves be felt earliest in their most vigorous form. There is no hope of sloving these problems without close international cooperation. 22 ROTTERDAM, ENVIRONMENT AND COMMERCE By W. H. Fockema Andreae President of the Rotterdam Chamber of Commerce and Industry- Just like any industrial country in The Netherlands, environmental problems have become a subject of public concern. In this country, and even more in Rotterdam, we have been studying and discussing environmental problems intensively during the last years. Environmental problems are not unknown to the Rotterdam area. Long before the rapid industrial development of Botlek and Europoort started after the second world war, our people had been confronted with pollution from other sectors of the economy in our own area or from sources outside our area. The Rotterdam drinking-water, coming from the river Rhine that passes the biggest industrial agglomerations of the European continent be- fore it reaches Rotterdam, has always had a special flavor. Some very con- servative inhabitants of our city complain about the amelioration of the quality during the last years — just like some more or less professional jokers who are losing a source of inspiration. Environmental control has become one of the most important issues of the industrial society of the 1970' s. Especially last year the United States, Japan and Western Europe were confronted with a strong and often emotional reaction from the public against different types of pollution. Therefore government and business life have to realize that the man in the street is worried about his environment. We shall have to realize that with an increase in welfare, demand will increase not only for the products of modern industry, but also for the free goods like fresh air, fresh water, nature and silence, that become scarcer. I think we cannot do away with these emotional reactions by saying that it is not possible to have a rational discussion with those, especially of the younger generation, who protest against the menacing deterioration of our environment. First of all we shall have to explain to them, that environmental problems are by-products of the welfare we enjoy nowadays in the industrial world. Without industry and the products of industry, pollution might be smaller, but welfare also would be smaller. On the other side we should consider the possibilities continuation of economic growth offers us for developing techniques and systems to reduce environmental problems as much as possible. Secondly, we should explain that in our complex world it is not only industry or business life in general that is causing .pollution, but that the consumer has his free choice in buying goods and services that cause pollution of different types. Pollution caused for instance by exhaust- fumes of cars is the consequence of the wishes of all of us as consumers. If we as consumers are prepared to pay a little more for privision in our cars and our gas to purify the exhaust- fumes , industry will certainly be able and willing to supply the technical devices. 23 We shall have to explain also, that the fight against environmental problems is not only a matter of technical innovation and government legis- lation, but that it will lead also to an increase in the costs of produc- tion — and sometimes even distribution. This will result in higher prices for products with a high "pollution content" but we should not forget that in our growing economy we will be able to pay for this, and that we can reach a higher level of welfare and well-being. Finally, we shall have to explain not only to the public, but also to governments and business-life, that environmental problems should be dealt with in our "worldwide village" as international problems. Air and water pollution do not stop at the frontiers and not even for the oceans, so here the need for international cooperation is evident. But international cooperation is also necessary to prevent distortion of compe- tition. If one country takes those problems seriously and another country does not take effective steps to fight pollution, firms investing in the first country will be at a disadvantage, and the same thing applies for export-products from that country. As it was rightly emphasized during the Congress of the International Chamber of Commerce in Vienna last month, or- ganized business life and governments will have to work for an international coordination in the fight against pollution. 24 ENVIRONMENTAL MANAGEMENT IN POLAND By W. Janiszewski Vice-President, Central Water Resources Board (CUGW) Warsaw, Poland The problems connected with the human environment have been noticed and undertaken in Poland relatively early. The State Council for the Pres- ervation of Nature, as an advisory body to the Government has been acting since 1919, and the League for the Preservation of Nature, a social organi- zation, popularizing the ideas of the nature preservation has been acting since 1928. Several elements of the human environment as geosphere, hydrosphere and atmosphere are in Poland under legal protection on the basis of issued resolutions and decrees. Taking into consideration the extremely wide and comprehensive aspect of the problems of environmental protection and rapid economic development, one of the most important questions is to ensure full cooperation and coordination of all involved institutions and organizations As a consequence, the interdepartmental coordinating body, the Polish Com- mittee on Human Environment Protection, was called into being in 1970 by the Order of the Prime Minister. The Deputy Prime Minister is the Chairman of the Committee, the vice- chairmen are as follows: President of the Central Water Resources Adminis- tration; President of the Polish Academy of Sciences; Vice-Minister of Foreign Affairs; Vice-President of the Planning Commission by the Council of Ministers; and the Vice-President of the Committee of Science and Tech- nology. The representatives of several interested Ministries, Committees and social organizations are members of the Committee. The main tasks of the Committee, which is the governmental advisory and coordinating body are initiation, appraisal and coordination of activ- ity of the Ministries and institutions involved in environmental protection and also determination of the trends and scope of cooperation in this field with international organizations. The tasks of the Committee are as follows: Consideration and evaluation of the relationship of environmental problems with long and short term planning of economic and social develop- ment . Suggestions for governmental long-term policy in the field of human environment protection. Consideration and giving opinions on long-term plans of govern- mental departments and institutions in the sphere of human environmental protection. Review and initiation of the legal acts and decrees relating to the rational management and control of environment. Review of actions and international programs in the field of environmental protection and also initiation of cooperation with interna- tional organizations. 25 Initiation and evaluation of comprehensive studies in Poland as well as the control of the scientific and technological progress in this field. The atmosphere and water resources have the most important meaning among the components of the natural environment. The Central Water Re- sources Administration has been charged with the management of these prob- lems through planning, coordination, determination of the principles and methods, initiation of the legal acts, control and supervision. The problem of air pollution is continuously increasing and its social and economic aspects are becoming international ones. Air pollutants are transferred very often to places beyond the boundaries of one country so the struggle against their effects on the natural environment and human life requires comprehensive preventive means, not possible to be undertaken by an individual country. So, it is necessary to underline that only the common and coordinated effort undertaken by many countries can restrain the increasing pollution and devastation of the natural environment and also the negative changes of living conditions in industrial regions. The present emission of air pollutants in Poland is estimated to be about 4 million tons of dust and about 3 million tons of sulphur oxides an- nually. The problem of air pollution is most acute in the Silesia-Cracow Industrial Region, which apart from the Ruhr Coal Mining Region in German Federal Republic, is the area of the highest concentration of heavy indus- try in Europe. The greatest devastation of nature and especially of the conifers is observed in this region. The reconstruction of forests has been commenced in these areas. The resolution on atmospheric pollution adopted by the Polish People's Republic Seym in 1966 and the executive acts issued during the period 1966-1967 created the legal basis for air protec- tion in Poland and enabled the activity leading to the limitation of the harmful influence of industry on environment. The efforts already undertaken so as to improve the situation in the field of air protection have been directed mainly to: Recognition of the present status in the field of pollutants emission in the industrial regions of the country as the principal condi- tion for the elaboration of programs of activity. Counteraction against further increases of air pollution and its harmful effects on the natural environment by using the adequate technical means . Activity in the field of air protection has already given measurable effects in the struggle against dustiness caused mainly by electric power plants and cement factories and has enabled the utilization of the volatile dusts in the building industry. A further decrease of dust emission by about 17 per cent is foreseen by 1975. The technology of the dedusting process has been recognized in Poland and it is being continuously improved. Now we have plants manufacturing dust-collecting facilities which are of high effectiveness, especially electrofilters. Further efforts in this field are being aimed at the de- velopment of a production basis by the organization of new design offices. The main trend in the air pollution control in the future will concen- trate on the limitations of emissions by technological changes in produc- tion processes, proper exploitation and maintenance of the facilities for treatment of gases emitted to the atmosphere, heating network construction, etc. Central heating and gasification in cities and electrification of 26 railways are being utilized more widely than ever before. Many cities in Poland have very considerable heating networks both for heating and technological purposes. It has enabled the considerable im- provement of situation in Lodz, for example, the biggest textile industry center in Poland. Similarly, Warsaw, 50 per cent of which is heated by two big electric power plants is, in spite of the industry located there, one of the cleanest cities in Europe. Further development of air protection depends, first of all, on the results of scientific and research works and proper recognition of air pol- lution status. At present in Poland about 40 scientific and research in- stitutions have included in their plans of research works the problems of air protection. However, extremely wide problems of the scientific and re- search works are beyond the possibilities of even highly developed countries of the world. These problems can be solved, first of all, by international cooperation. At present Poland takes part in efforts on these problems as a member of the Council for Mutual Economic Assistance and the Economic Commission for Europe as well as in organizing the international confer- ences and seminars. The problem of water protection against pollution is also or great im- portance in Poland. The continuous increase of the quanity of wastes re- sulting from the economic development of the country and the increasing population creates the necessity of the struggle against river pollution and connected with this the difficulties in supply with water for the pop- ulation and national economy. To illustrate the problem the following figures may be quoted — the quantity of wastes in 1960 amounted to about 4.8 billion cubic meters and in 1970 it reached about 8.0 billion cubic meters. Thirty-five per cent of river courses in Poland are polluted to a degree exceeding the admis- sible standards. In order to improve the situation and first of all to prevent further harmful effects, the elaboration of a long-term program of activity based on proper legal, technical and economic bases has been necessary. The legal basis for activity in the field of water protection against pollution is the "Water Law, " the resolution issued in 1962 along with the executive acts. It adjusted the previous legal acts in this field to the contemporary social and economic conditions in the country. The above-mentioned acts determine the obligations of industrial plants and people discharging their effluents into waterways and conditions for issuing permits for wastes discharging and requirements for water qual- ity in accordance with their utilization. The activity in the field of water protection against pollution is conducted by the State Inspection for Water Protection acting in the framework of the Central Water Resources Administration. Also this activ- ity is conducted by 20 voivodship divisions of water, and air protection through about 100 local units. The divisions have laboratories for water and wastes studies which deal with the laboratory control of pollutants in effluents discharged by industrial, municipal and other plants, as well as with the measurements of surface-water quality. Work in the field of water pollution control concentrates on three main directions: Design, construction and operation of treatment facilities. Control of the execution of the regulations on water protection. Scientific works. 27 In the field of the design we possess the resources enabling us to work out the required documentation for the construction of treatment plants de- spite the increasing number of tasks in this field. The special office to ensure the optimal organization of the design effort has been called into being within the framework of the Ministry of Building and Building Materials Industry. This office coordinates the works of 80 design offices dealing with the treatment plant designs. The intensive investment activity in the field of treatment plant con- struction is being conducted so as to prevent the harmful effects of waste- waters. While determining the priorities for investment in treatment plants plans the principle is to concentrate the expenditures first of all on highly economically developed basins of the Upper Vistula and Upper Odra Rivers, the two biggest rivers in Poland, where the difficulties with water supply of adequate quality are especially observed. A considerable part of the expenditures is destined for regions es- pecially to be protected because of water intakes, tourism, recreation, etc. The activity mentioned above has limited the increase of river pollu- tion despite economic development of the country. However, a general im- provement of water quality has not yet been achieved. The scientific works in the field of water protection against pollu- tion in Poland are being carried out by about 60 institutions and scien- tific institutes employing about 600 highly qualified specialists of various scientific disciplines. The considerable part of these works executed by the different bodies and dealing with the technology of effluent treatment is coordinated by the Central Water Resources Administration. Among the above-mentioned scientific and research institutes dealing with water and wastewater the following should be mentioned: the Water Economy Research Institute, the Research Institute for Municipal Economy, the State Hygiene Institute, the Main Institute for Mining, the Research Institute for Ferrous Metallurgy, and the institutes of the Polish Academy of Sciences. The main directions of the investigations involve the following prob- lems: Improvement of treatment technology and construction of facilities in specific industries. Reuse of wastes in production processes in closed cycle systems. Water self-purification processes and determination of the admis- sible pollution standards. Recovery of raw materials contained in wastes. Management of waste sludge and solid wastes. Methods for the counteraction against causes and results of water eutrophication and pollution caused by fertilizers in agriculture. Certain achievements in several fields can be mentioned: Improvement of the methods and facilities for phenols recovery from ammonia water in coke by-product plants. Elaboration of the biological method for treatment of phenol wastes by the activated sludge process. Elaboration of the biological method for treatment of phenol wastes in biological ditches. 28 Elaboration of the biological method for treatment of wastes from sulphite cellulose productions. Elaboration of the biological high-duty activated sludge process for treatment of wastes from dairies in the biological ditches character- ized by low costs of construction and simple operation. Great importance is attached to the exchange of experience in this field with other countries. One of the most efficient means of establish- ing such exchanges is meetings of specialists which enable the mutual pre- sentation of scientific and technical achievements and discussions of existing problems. 29 WATER POLLUTION CONTROL 30 NEW DIRECTIONS FOR WATER POLLUTION CONTROL By Daniel A. Okun Head, Department of Environmental Sciences and Engineering University of North Carolina at Chapel Hill A concern for water pollution control is not of recent vintage, at least not in Europe. The renowned English poet, Samuel Taylor Coleridge, in his poem "Cologne", written more than one and a half centuries ago, characterized the Rhine River in words that are appropriate today. In Cologne, a town of monks and bones And pavements fanged with murderous stones, And rags and bags and hideous wenches, I counted two and seventy stenches All well defined, and several stinks! Ye Mumphs that reign o'er sewers and sinks, The River Rhine, it is well known, Doth wash your city of Cologne; But tell me, nymphs, what power divine Shall henceforth wash the river Rhine? Engineers and scientists have for more than a century addressed them- selves to the technology of water pollution control. Had they not, this congested continent would today be uninhabitable. However, population growth, increasing urbanization, increasing industrialization, and most significantly, increasing expectations for a better life, have focused public attention on the problems of water pollution control. Our response to society must include not only technological improvement, but also insti- tutional change and innovation, innovations akin to those introduced in the Ruhr region at the turn of the century. In the organization of the Ruhrverband, it was recognized that waste- water is a resource and out of necessity and economy it must be reused. This was accomplished in part through common ownership and operation of water and wastewater enterprises. If water quality management is to be effective, close cooperation between water resource and water pollution control authorities must now be institutionalized everywhere. Parochial and professional loyalties and interests should no longer dictate how problems of water quality management are handled. National, state, and local governments cannot be encouraged to initiate joint water-wastewater endeavors if the appropriate professional organi- zations are not willing to provide some leadership. In many countries of Europe, as in the U.S., professional engineering organizations exist separ- ately in the fields of water supply and water pollution control. In the U.S., most environmental engineers are members of both types of organizations and are expert in both fields. This is less common in Europe where water supply and water pollution control are quite separate endeavors. An effort must be made to merge these interests to demonstrate to society the common- 31 ality of water supply and water pollution control problems and that we will not let our traditions interfere with their efficient solution. Regional Organization Water supply and water pollution control have been characterized since their initiation as municipal responsibilities. This has begun to change because the economies of scale in construction and operation reveal the reasonableness of regional solutions. The regrouping of municipal water supplies in England (1) into fewer, larger systems, from 1300 to fewer than 300, and the regional water supply networks in the Netherlands, have demon- strated the effectiveness of this approach. However, this is not so common in the management of wastewaters. In an excellent review of regional management of wastewater utilities, some recent accomplishments in the U.S. are described (2) . For example, in a county in upper New York State, thirty-four separate treatment facilities are being replaced by four large treatment plants, while in another instance, one plant is replacing seven existing smaller plants. However, this regionalization does not consider integration with water supply facilities nor does there appear to be any incentive for such integration. Regionalization of water supply systems with wastewater collection and disposal facilities into larger regional water resource management systems is a must for the future. Such arrangements would help avoid the many instances where one community's wastewater becomes the source of water supply for another community downstream. Larger size facilities would make possible the employment of qualified managers, engineers, and laboratory personnel in common enterprise to assure the region of high-quality water and efficient water supply and wastewater disposal service at lowest cost without objec- tionable impact on the environment. Such regionalization would undoubtedly threaten the sovereignty of many municipal organizations and the positions of many individuals. However, the need for personnel will continue to grow and qualified individuals will always have a place for productive employment regardless of the institutional arrangement. At both the government regulatory level, as well as at the local operating level, the water pollution control agency is generally separated from the agency responsible for water supply. At federal level in the U.S. they were once together in the Public Health Service, then they were separated, and as of a few months ago they are together again, with air pollution, solid wastes, radiation and pesticide control in the new Environ- mental Protection Agency. At the local level, separation is still the general rule. Reuse of Wastewaters for Water Supply Joint enterprise in water supply and wastewater disposal does not imply that wastewater need be or should be used for potable supplies although this is the common inference when reuse is mentioned. As Hansen has pointed out, the U.S. Public Health Service Drinking Water Standards state: "The water supply should be obtained from the most desirable source which is feasible, and effort should be made to prevent or control pollution of the source" (3) . The same philosophy is embodied in the WHO Drinking Water Standards. In assessing the quality of drinking water supplies we have far too 32 long depended upon bacteriological quality, and had to a limited extent on chemical quality, and have neglected the precept that the water should originate from a protected and high-quality source if at all feasible. We would be distraught if we believed that our milk came from diseased cattle living in filthy barns even though we know that dairies have the technology to pasteurize the milk adequately. Accepting highly polluted waters or wastewaters as sources of drinking water supplies may have been acceptable sixty years ago when the only con- taminants of concern were bacterial pathogens and we were certain that treatment and disinfection would assure their destruction. However, today the quality problems of water supply are no longer so easily managed. The destruction of viruses is uncertain and the large number of chemicals emanating from modern industrial operations are little reduced and certainly not eliminated in conventional wastewater and water treatment practice. Treatment plants are not likely, in any reasonable time in the future, to be designed for removal of these chemicals, some of which are carcinogenic, mutagenic and/or teratogenic (4) . Public Health Service Drinking Water Standards do not apply to the direct reuse of reclaimed wastewaters for drinking, because (1) the poten- tial for toxic substances is high and variable, (2) fail-safe devices have not yet been developed, and (3) the monitoring for these low levels of toxic substances is not adequate for quality control (3) . In California, where water is severely limited, officials have stated that "...the economics of treatment, quality control, monitoring and assured safe operation presently preclude the production of a suitable water from wastewater for certain purposes where quality requirements are high", and therefore no standards have been established for the direct reuse of waste- waters for domestic purposes although standards for the reuse of wastewaters for non-potable purposes have been established (5) . A proposal by the Public Health Service in 1965 to augment New York City's water supply which comes from well-protected upland impounding reservoirs, by adding reclaimed wastewaters directly to the distribution system has apparently passed into limbo. In that report it was stated that the augmented supply would meet or exceed every requirement of the Public Health Service Drinking Water Standards and would be a completely safe, reliable and aesthetically acceptable supply. The author of this proposal had given no attention to the potentially toxic chemicals that are inevit- ably present in the wastewaters from a major urban area. The current Drinking Water Standards do not address themselves to the presence of specific organic chemicals that have potential for toxic effect when very large populations are exposed to them continuously. Although this proposal to augment New York City's water supply with its own wastewaters has not been revived, there is a revival — as there has been many times before — of the proposal that additional water supply for New York, to augment the high-quality upland source, be obtained from the Hudson River, the drain for much of industrialized New York State. This selection among alternatives, a more-expensive high quality source versus a cheaper poor quality source, is one that many cities are faced with. Even in Germany where water resources are extremely limited, particu- larly in the industrial regions of the country, it has been agreed that because of both health and psychological problems "wastewater cannot be used directly for drinking and other domestic purposes" (6) . In Germany, filtration, dilution and time in underground percolation and storage have 33 been used for many years to help render a polluted surface water acceptable. Accordingly, direct surface waters provide only 9% of the total municipal supply in Germany while 26% is taken from surface sources via percolation and passage for from 40 to 100 days in the ground. In Britain, "...the direct recycling of sewage effluent is not con- sidered desirable because of the possible intensification of risk to public health" (7) . There, the reclamation of treatment plant effluents for industrial use is receiving high priority. To cite the one well-known instance in the United States where, for several months as an emergency measure, wastewaters were recycled for water supply, in Chanute, Kansas, according to Haney, "The public accepted the situation but rejected the water" (8) . A Scientific Group of the World Health Organization, in its evaluation of direct reuse of wastewaters for human consumption, pointed out that "...not enough is known of the long-term effect of certain of the trace chemicals found in wastewater, and there is still much to be learned con- cerning the removal of the more persistent forms of microbiological pollution such as some of the enteroviruses" (9) . If there is not to be direct use of wastewaters for domestic water suppl what is the prospect for water reclamation in urban areas that are rapidly exhausting their current supplies of high-quality fresh water? These waste- waters can be used directly for purposes that do not require the high quality that is necessary when the water is to be used for drinking. Every urban center has within it and in its immediate environs many water needs that can be met with water of lesser quality, such as industrial use for process and cooling, irrigation, large-scale cleansing operations such as for streets and automobiles, recreation and the creation of aesthetically pleasing water bodies in recreational areas. To the extent that high-quality drinking waters are now used for any of these purposes, and this amounts to virtually all urban irrigation, indus- trial process use and cleansing, to that extent are scarce fresh water resources being squandered. In only very few instances, where fresh water has been in extremely short supply and its value high, has there been any planned attempt to utilize reclaimed wastewaters for these purposes even though the precedent was established decades ago in Baltimore where its treated wastewaters have been purchased by the Bethlehem Steel Company. However, it is good to know that the situation is rapidly changing. The City of Los Angeles has studied the use of reclaimed water for ground water recharge, for the prevention of sea water intrusion, for irrigation, for the creation of recreational and ornamental lakes, and for industrial water supply for oil refinery process water and cooling. The City of Pomona Water Department is distributing reclaimed waste- water from the Los Angeles County Sanitation District for agricultural irrigation, including citrus and walnut grove irrigation, highway land- scaping, and highway construction. An unheralded but most appropriate development has been that at Colorado Springs, where about one third of the biologically treated waste- waters is given rapid sand filtration on mixed-media filters, disinfected and then stored and distributed through an extensive second distribution system for sale as irrigation water to college campuses, cemeteries, golf courses, and other large users. Part of this reclaimed wastewater is given lime coagulation and sedimentation for phosphate removal and then passed through rapid sand filters and carbon beds for removal of organic chemicals, 34 and sold as industrial water. Supply of the reclaimed wastewater is limited to customers using more than 10,000 gallons (38,000 liters) per day. The reclaimed wastewater sells for only 2/3 the price of potable water. By 1980, 90% of Colorado Springs wastewaters are expected to be reclaimed, putting off major investments that would otherwise be required for additional water supply to be obtained by tunneling through the continental divide. A discriminating pricing policy can encourage the use of reclaimed wastewaters, with a high unit price for high-quality potable waters, and a lower price for reclaimed wastewaters. Something along this line has been suggested in the Soviet Union, where 43 per cent of the pure high-quality water supplied to Russian cities is used by industries that do not require water of drinking water quality. It is proposed to price this pure water beyond the reach of those who use such waters for industrial purposes. Wastewater Reuse for Public Water Supplies Utilization of reclaimed wastewaters for industry, agricultural irri- gation, and for recharge has a long way to go before their full potentials are realized. However, when all such needs are met, or in situations where industrial, agricultural and recharge opportunities are not available, as in strictly residential communities in metropolitan areas, another alterna- tive may very well become attractive. This is the utilization of reclaimed wastewaters for municipal uses that do not require water of a high quality, such as for household and urban watering, for cleansing, and for toilet flushing. Dual water supplies had been proposed earlier (10) , (4) . The image that is created by a proposal for a dual water supply is the exten- sive requirement for a second water system and the high costs that result therefrom, as well as the possibilities of cross-connections. However, when we recognize the order of magnitude of present and future housing programs, with their high population densities in multi-family structures of all sorts, the prospects for what might be considered an "industrial housing water supply" for non-potable purposes do not appear to be much different from those for providing a reclaimed wastewater supply for any other industry. The design of modern urban centers is little different from the design of industrial facilities, with service corridors and shafts that permit carry- ing many utilities readily to a wide number of users in a relatively small space. The provision of two water supplies in such settings is not any more incongruous than two or more supplies for an industrial complex, or separate sanitary and storm sewers. One objection to such dual supplies is the danger of cross-connections, or of accidental drinking from the lower class system. Adequate disinfec- tion would assure that inadvertent use would not lead to infectious disease. An accidental ingestion of the chemical contaminants in the second supply, at the concentrations that are likely to be present in wastewaters, would not be harmful. It is the lifelong ingestion of chemicals from polluted waters, chemicals not removed in conventional water treatment, that is potentially dangerous. The Application of Reclaimed Wastewaters to the Soil Following the first public outcry against pollution in London in the mid-nineteenth century, the solution was the application of London's waste- water to the soil for treatment and disposal. Although the "sewage farm" 35 has fallen into disfavor, the application of reclaimed wastewaters for irrigation as well as wastewater disposal is once again finding a place. Water supply costs will be increasing substantially in the future, and the need for water will be matched by the need for fertilizer. At current prices for ammonium nitrate, triple superphosphate and potassium chloride, the value of the nutrients in reclaimed wastewaters amounts to some 5.5 cents per thousand gallons (3800 liters) not including the value of the water (11) . The assimilative capacity of soils for wastewaters is only now beginn- ing to be studied intensively. The U.S. National Academy of Science has pointed out that "... (Soil) has a great capacity for receiving and decom- posing wastes and pollutants of many kinds" (12) . The assimilative capacity of soils for the decontamination of wastewater results from filtration, biodegradation, and physical and chemical absorption (13) . The assimilative capacity is a function of the chemical character of the wastewater, the character of the soil, and the nature of the soil-wastewater reactions. Soils must be examined in the future for their assimilative capacity just as receiving waters were assessed for their assimilative capacity, although the establishment of parameters for the assimilative capacity of soils is far more difficult. In the case of soils, the wide variations in soil characteristics, not only from place to place but within a specific area, the non-isotropism and the heterogeneous character of most soils make it mandatory that each situation be studied intensively before any large-scale program of application of wastewater to the soil is undertaken. Hopefully, as information is gathered from widely varying situations, useful guide- lines for wastewater disposal by land application may be developed. However, rates of application that can be attained even under the best of circumstances with the most assimilative soils and the highest level of wastewater treatment are such that land disposal is only likely to be appropriate in certain locations, generally where suitable land is available Where population densities are high, only relatively small portions of the total wastewater could be applied to the soil. However, even minor efforts at recharge with wastewater may help redress the growing loss of ground water resulting from urbanization, where permeable fields give way to impermeable membranes of asphalt and concrete. Characterization of Wastewaters Regardless of how successful we may be in consigning polluted waters and wastewaters to second class non-potable uses, a substantial portion of the population will be obliged to use polluted waters for their potable supplies for years and even generations into the future. The simplistic characterization of wastewater quality by means of BOD, COD, and even TOC is no longer adequate where wastes find their way into drinking water supplies. Treatment plants, whether for wastewater or for water supply, are not adequate to remove or even substantially reduce the concentration of most organic chemicals and their metabolites or the heavy metals that are likely to be of concern. Studies in England revealed that wastewaters from municipalities contained two well-established carcinogens, 2, 4- benzpyrene and 1, 2-benzanthracene. These chemicals have also been identi- fied at concentrations greater than 700 micrograms per cubic meter in samples from the Rhine River which is extensively used as a water source in Germany and the Netherlands (14) . 36 If we are not to be continuously surprised by so-called "new" pollution problems such as arose with pesticides and mercury, surprises that almost inevitably result in hasty, ill-considered legislative and regulatory responses, we must ourselves initiate programs of surveillance that will anticipate problems. This must be handled from at least two widely dis- parate vantage points: (1) Intensive water quality surveillance programs must be insti- tuted in an attempt to identify and quantify all suspected contaminants in water. A protocol for examination needs to be developed and more sophis- ticated tools are required both for the concentration of these trace chemi- cals and for their analysis. The carbon chloroform extract is entirely inadequate for the purpose, as it misses an unknown portion of wastes that are not absorbed on the carbon column and because the analysis of the absorbed material is not well structured. Another approach that should be investigated is the use of selective membranes in series or in parallel to concentrate contaminants, a procedure which would help assure that no chemicals of likely significance would escape the analytical process. After the contaminants are concentrated, the increasingly sophisticated tools of modern analytical chemistry must be used so that analyses can be made routine and reproducible. Data must be amenable to continuous recording on computer tape so that sudden changes in quality are detected and so that the masses of data can be analyzed for trends in water quality improvement or deterioration. (2) Comprehensive "sanitary surveys" must be conducted. Because of the very large number of chemicals that may be in a major river that serves as a water supply, it is virtually impossible to attack a water sample with any confidence that all potential contaminants can be identified, unless there is prior knowledge of the materials that are discharged to the water in the first place. What in the early days of water quality manage- ment was called the "sanitary survey" must now constitute a comprehensive materials balance so that all materials coming into the watershed can be measured and their disposition determined. This would give presumptive evidence of the contaminants likely to be present and would be a guide to the analyst as to what he should be seeking in his analytical water exami- nation. Without knowing what we are looking for it would be impossible to detect the presence of many troublesome constituents, much less to design facilities for their removal. Such surveys of materials that enter into industrial processing do threaten the confidential nature of industrial enterprise, but there is no alternative. Arrangements must be made for administrative protection for industry, in much the way that tax agencies provide secrecy for proprietary information. Chemical Treatment Until high degrees of treatment than can be accomplished by conven- tional biological treatment are required, and this is now beginning to be the case, there has been no incentive for developing the more sophisticated chemical processes that would be expected to remove specific contaminants. Modern biological processes are relatively inexpensive, and it is not likely that new sophisticated chemical processes will replace them for the bulk of the waste treatment that needs to be accomplished. However, in those instances where specific contaminants, be they toxic substances or nutrients, 37 need to be removed, chemical treatment offers new opportunities. These chemicals include not only the conventional coagulants and conditioners, but also pure oxygen, oxidants such as bromine and ozone in addition to chlorine, and a wide range of organic chemicals many of which may be designe for specific uses in water or wastewater treatment. Others in this seminar are discussing new technological approaches to wastewater treatment. Treatment in Sewerage Systems The increasing use of certain chemicals may make attractive what has been a long-neglected opportunity to utilize existing facilities for improve wastewater treatment, namely, treatment in the conveying conduits of the sewerage system. At a velocity of two feet (0.6 meters) per second, one kilometer of sewer provides a detention period of almost half an hour. A system would not need to be large to provide detention within the sewerage system of the same order or magnitude as the detention in the treatment plan itself. Some imagination might very well go into encouraging stabilization or treatment of the wastes within the system. One small step in this direction has been the proposal that additives might increase the carrying capacity of the sewers (15) . The addition of 40 to 60 milligrams per liter of a chemical additive increased the flow-carrying capacity of a sewer by 80 per cent, while 100 milligrams per liter increased the flow 110 per cent. Ancillary benefits allegedly included up to 40 per cent increase in sedi- mentation efficiency and improved dewatering qualities of the sludge as the dosage of additive was increased. While no cost data are yet available, the possibilities seem interesting indeed, particularly where long lines would reduce unit costs of the chemicals. The addition of nitrous oxide gases at the head end of a sewer system has been claimed to reduce the BOD of the treatment plant influent substan- tially as well as helping to reduce grease collections in the sewer system and avoiding septicity. The possibilities for treatment within a sewer system have not really begun to be explored. They include not only chemical treatment, but bio- logical treatment as well. Air or oxygen might be introduced into the larger intercepting and truck sewers, or biological floe might be recircu- lated or affixed to media in the conduit. Sewers of the future might be enlarged to provide surfaces for biological growths without interfering with flow capacity. The additional cost might be small compared to that required to accomplish the same degree of treatment at the plant. Similar efforts might be appropriate in the wet wells of pumping stations, which are now used only as flow regulators. Pressure Conduits Extensive studies have been made of the feasibility of using pressure sewers to replace conventional gravity sanitary sewers (16) . In typical urban areas, pressure systems have been estimated to be costlier than con- ventional sewer systems, mainly because of the costs of grinders and pumps required for individual households in the system. In only one instance, to this writer's knowledge, has a pressure system been used, and this because of special topographical conditions (17) . Again, while it may be too adventuresome to introduce so major a 38 :hange in sewerage system design throughout an existing community, pressure sewers would appear to be entirely justified and likely to be economically feasible for new systems serving densely populated buildings whether they ire hotels, multi-family housing units, office buildings or commercial complexes such as shopping centers. In such circumstances, the pumps required for a pressure system, and even the provision of standby power, ;ould not be unreasonable, and a substantial saving would accrue from the ise of smaller size sewers and the relaxation of grade construction. Adoption of pressure sewers would be appropriate in sprawling metro- politan areas with new densely populated satellite communities, particu- .arly where the terrain is flat or where the topography and the land use >lans are not hospitable to gravity sewers. Of course, pumping stations ind force mains are now widely used in sewerage systems, but they are .ncorporated only as a reluctant alternative to gravity flow rather than is a studied part of an overall design. With the rapid improvement in >umping technology and the relative lowering in power costs as compared /ith construction costs, the utilization of pumping and smaller-diameter 'orce mains will become increasingly attractive as an alternative to .arger size gravity conduits. And in the provision of utilities for :ities of the future, the pressure sewer will be much more compatible with he utility tunnel, or utilidor, than the gravity sanitary sewer. lanpower and Womanpower Wastewater treatment facilities at present are recognized to be inade- [uate both in their number and in the degree of treatment they provide. !ven under these circumstances, the personnel required to operate these acilities is insufficient and largely inadequate in competence to meet rurrent requirements. It has been demonstrated that the revenues per unit >f capital investment in the water and wastewater field are far below those : or the other utilities (18) . Payment for wastewater facility operating iersonnel is far below that for other utilities. Accordingly, many waste- 'ater treatment plants, particularly those serving medium and small size lommunities, are operating far below their intended efficiencies because if the lack of qualified supervision and also because of insufficient egulatory control. A facility may be visited only once every few years »y regulatory officials and even where reports are required regularly, he manpower in the headquarters or the regional offices of the regulatory organizations is insufficient to review their content. We will need an rder of magnitude increase in manpower, nor should we forget womanpower, ,f an appropriate benefit from the increasing capital investment in water ollution control is to be obtained. However, in the U.S. the portents are not good. The number of students intering engineering is not keeping pace with increased population. In ,965, only 9.5 per cent of college men were engineering students as compared dth 13.7 per cent in 1955 (19). Men's interest in engineering has been leclining, and women have not shown any increase in interest. While only hree of 100 engineers in the United States are women, the figure in the loviet Union is more than 30 per 100. In the USSR, the enrollment of women .n engineering schools is more than double the total enrollment of men and 'omen in engineering schools in the United States. (The number of women >articipating in these seminars in Warsaw and Bucharest is encouraging) . 39 Even when likely candidates are found in the engineering schools, a good many of those who go on to practice have not had the graduate study which provides the special competence required for the field of water pollution control. The increasing generalization of undergraduate curricula requires that, if an individual is to be properly prepared, he or she must plan to go on the specialized graduate study. Some 85 per cent of practicing engineers surveyed in the U.S. felt that they should have taken graduate study. The National Council of Engineering Examiners is recommending that one year of graduate study be a requirement for licensing in the future. Of all specialties in engineering, except for nuclear engineering, a larger percentage of sanitary or environmental engineers in the U.S. has completed the master's degree than any other specialty in engineering. However, the total number is still small. In Western Europe, the preparation of specialized environmental engi- neers is far less extensive than in the U.S. The well-known European Course in Sanitary Engineering at the Technological University in Delft, and the few well-known institutions such as those at Stuttgart, Zurich, Naples, and Vienna prepare far too few engineers to meet the needs of grow- ing programs of water quality management. The situation in Eastern Europe is far better, but still not adequate. And the training of specialized technicians for plant operation, and for water monitoring is entirely unsat- isfactory. The World Health Organization has taken some initiative in education, but this is only a beginning (20) . The situation is not bleak, however; with the increasing interest in the quality of the environment, and the growing commitment on the part of young people towards devoting their lives to socially useful pursuits as contrasted with simply materialistic objectives, the opportunity for increased recruitment to work in the field of water quality management is great. We have seen this in the numbers and in the quality of those apply inc for graduate study in the Department of Environmental Sciences and Engineer- ing at the University of North Carolina, and I am confident that the same situation prevails at other educational institutions. It behooves us to build upon this newly developed interest to make prospective engineers aware of the opportunities in this field, and to increase the resources for specialized education and training. With industry's growing responsibility in water quality management both in solving their own pollution problems and in providing the hardware for water pollution control generally, industrial. organizations should sponsor training for their own personnel and assist educational institutions with their programs. The ultimate hope for the changes that represent the appropriate response to societal needs rests with our young engineers and scientists, and we must encourage them. References 1. Daniel A. Okun, "Regrouping of Water Supplies in the United Kingdom", Public Works . 98, 153, June, 1967. 2. "Regional Management of Wastewater Utilities", Journal, Water Pollution Control Federation , Vol. 23, 1-29, 1971. 40 3. C. A. Hansen, "Standards for Drinking Water and Direct Reuse", Water and Wastes Engineering . Vol. 6, No. 4, 44, 1969. 4. Daniel A. Okun, "Alternatives in Water Supply", Journal, American Water Works Association. Vol. 61, 215, 1969. 5. Herbert B. Foster, Jr. and William F. Jopling, "Rationale of Standards for Use of Reclaimed Water" , Journal. Sanitary Engineering Division . Proceedings . ASCE, SA3, 503, June, 1969. 6. Reuse of Wastewater in Germany, Organization for Economic Cooperation and Development, Paris, 29 pp., 1969. 7. D. G. Miller and D. H. Newsome, "Conservation of Water by Reuse in the United Kingdom", Chemical Engineering Progress Series . AICHE 63, pages 13-31, 1967. 8. Paul D. Haney, "Water Reuse", Journal. American Water Works Association . Vol. 61, 73-78, 1969. 9. Treatment and Disposal of Wastes . Report of a World Health Organization Scientific Group, Technical Report No. 367, Geneva, 1967. 10. Paul D. Haney and Carl L. Hamann, "Dual Water Systems", Journal . American Water Works Association . Vol. 57, 1073, 1065. 11. Lawrence Hirsch, "Irrigation with Reclaimed Wastewater", Water and Wastes Engineering . Vol. 6, No. 4, page 58, 1969. 12. National Academy of Science, National Research Council , Waste Manage- ment Control . Publication 1400, Washington, D.C. 1966. 13. B. F. Hajek, "Chemical Interactions of Wastewater in a Soil Environ- ment", Journal, Water Pollution Control Federation . Vol. 41, 1775-1786, 1969. 14. Robert A. Baker and Bernard A. Malo, "Water Quality Characterization — Trace Organics", Journal. Sanitary Engineering Division. Proceedings . ASCE. SA 6 . 41-54, December, 1967. 15. J. J. Overfield, et al, "Increasing Wastewater Flow Velocity by Using Chemical Additives", Journal. Water Pollution Control Federation . Vol. 41, 1570-1585, 1969. 16. M. B. McPherson, Reports on Studies of Pressure Sewers, Am. Soc. Civ. Eng. , New York. 17. Mortimer A. Clift, "Experience with Pressure Sewerage", J. San. Eng. Div. Proc. Am. Soc. Civil Eng. SA5 . 849, 1968. 18. Daniel A. Okun, "Tomorrow's Methods to Provide Tomorrow's Service", Journal, American Water Works Association . 58, 938, 1966. 41 19. Martin R. Van Eyck, "The Manpower and Educational Crisis in Water Pollution Control — Consulting Engineering" , Journal. Water Pollution Control Federation , 41 . 16, 1969. 20. The Education and Training of Engineers for Environmental Health, World Health Organization, Geneva, 1970. 42 NEW TECHNOLOGY FOR WATER POLLUTION CONTROL By David G. Stephan, Assistant Commissioner and John J. Convery, Special Technical Assistant Research and Development Water Quality Office Environmental Protection Agency Washington, D.C. USA If the decade of the seventies is truly to be the "Age of Aquarius," it must be a decade of action to control and prevent water pollution and to restore the quality of the waters of the world. President Nixon has recommended that the United States spend $12 billion for the construction of municipal pollution control facilities during the next several years with a re-evaluation of the resource requirements to be made in 1973. The costs involved in controlling all sources of water pollution, municipal, industrial, agricultural, mining and other sources, have been estimated to be on the order of $60 billion in the United States. While these sound like, and in fact are, tremendous investments, they represent, in perspec- tive, capital expenditures of only some $60 per capita for municipal sources and about $300 per capita for all sources put together. These investments would also be spread over a number of years. These costs can, and, in fact, should be compared with the current per capita investments in other utili- ties such as gas ($125/capita) , phone ($310/capita) , electric ($433/capita) and in federal highways ($618/capita) . A national commitment of this magnitude and an international commitment of significantly greater magnitude present a unique new challenge to indi- viduals involved in environmental quality control and particularly in re- search. The challenge is to go one step further and not just do research, but actively promulgate research findings to the users of this technology — and, moreover, not just promulgate isolated research results of limited scope but to transfer complete "packages of technology" to the user community. Packaged technology would include an array of process alternatives available for treating a specific waste, cost and performance information on the total wastewater treatment system, including consideration of the ultimate dispo- sal of brines and sludges, operating requirements and design guidelines. The most cost-effective technological developments possible for application in the immediate and near-term future must be identified. In October of 1970 a special program was announced in the United States to transfer, not just disseminate, the results of research to the potential users of new pollution control technology. This "technology transer pro- gram" is designed to demonstrate convincingly the technical and economic practicability and the reliability of research findings. The audience is composed of both the technician, i.e., the design engineer, the treatment plant operator, etc., and the non-technician decision-maker, i.e., the mayor, the legislator, the regulatory official, etc. Our objective is to insure that the latest techniques are incorporated into the design of 43 treatment and control facilities which will be constructed in the next sev- eral years. The technology transfer program utilizes a variety of communi- cations techniques: large presentations for general audiences, technical seminars for federal, state and local officials, design workshops for small groups of consulting engineers, publication of design manuals, use of film- strips and video tape presentations plus tours and lectures at demonstration facilities across the country where advanced waste treatment and pollution control methods are in full-scale operation. Primary emphasis is currently being given to the municipal sewered waste problem since this is the area where the greatest "Action-Effectiveness" (i.e., a qualitative assessment of pollution problem areas which combines the relative cost of control, ac- complishment in meeting standards, availability of technology and willing- ness and ability to proceed) can be achieved. Municipal Wastewaters Municipal wastes include combined domestic and industrial wastewater discharges which characteristically are a large source of degradable organ- ic material, bacteria and viruses and which contain nutrients that acceler- ate eutrophication of lakes and estuaries. Major emphasis in this area has been directed toward demonstration of lower cost and more efficient methods of removing organics, phosphorus and nitrogen. More than a dozen chemical treatment systems for the removal of phos- phorus as well as BOD and suspended solids are available today for full- scale application. System alternatives include the choice of chemical co- agulant (iron, alum or lime) and the point of chemical addition (to primary, secondary or tertiary processes) . Factors affecting the choice of chemical and point of addition are influent phosphorus level, effluent discharge re- quirement, wastewater characteristics such as alkalinity and pH, plant size, local cost of chemicals, sludge handling facilities, ultimate disposal al- ternatives and the conventional process utilized. Generally, a system utilizing iron or alum added before the primary clarifiers or aerators is selected where an effluent requirement of 1-2 mgle phosphorous is desired and the influent phosphorus concentration is low to moderate ( 10 MG/L) (Figures 1 and 2). An effluent phosphorus concentration of 0.5 MG/L can be achieved if a supplemental dose of coagulant is added prior to a terti- ary filtration step. Total operating costs for chemical addition to the primary or secondary step, including amortization of the chemical feeders and expanded sludge handling equipment, will be $0. 06-$ . 08/1000 Gal. In some locations, iron salts are available very cheaply as waste pickle liquor; a substantial reduction in chemical costs can be achieved if a reliable source of waste pickle liquor is available (Table I and Figure 3) . Lime treatment of raw sewage or secondary effluent would often be utilized in larger plants ( 10 MGD) where the economies of scale are signi- ficant and recalcination is economically practicable. Lime treatment is particularly advantageous when the influent alkalinity is low and the in- fluent phosphorus concentration is high. Effluent phosphorus concentrations of 0.5 MG/L are attainable without filtration and 0.05 MG/L can be achieved with filtration. Total operating cost, including amortization of the capi- tal investment, for a 10-MGD two-stage lime clarification system is about $0.09/1000 Gal. 44 A novel chemical treatment system which has recently been demonstrated is the moving bed filter (MBF) . The filter media, sand, is mechanically pulsed countercurrent to the direction of flow. The accumulated solids and the sand are mechanically guillotined at the filter surface, washed to sep- arate the filtered solids and the sand is recycled to the base of the filter. The removed solids are gravity thickened and can be dewatered in a rotary precoat filter. MBF has been successfully applied to alum-coagulate secon- dary effluent, unsettled trickling filter effluent, primary effluent and even raw sewage. (Figure 4) The filter is capable of handling high and variable suspended solids loads on a continuous basis. A 5-MGD plant in Manville, New Jersey, using the MBF with alum coagulation is in operation to significantly up-grade the trickling filter effluent quality and achieve 95% phosphorus removal (Table II) . Additional development work is being conducted to evaluate the concept of a single unit physical-chemical system using the MBF and powdered activated carbon. The Environmental Protection Agency has contracted for the preparation of a design manual which will present, in one document, design guidelines and cost information on all the alternative phosphorus removal techniques currently available. How extensively is chemical treatment being applied in the United States? A partial list of full-scale plants utilizing chemical treatment is shown in Table III. The total operating costs reported for chemical treatment cannot be at- tibuted entirely to phosphorus removal since a substantial improvement in the removal of organics and suspended solids is achieved simultaneously. Chemical clarification of raw wastewater will remove from 70-80% of the or- ganics and 90-95% of the suspended solids (Figures 5 and 6) . These results have stimulated a great deal of interest in the concept of independent physical-chemical (IPC) treatment utilizing chemical clarification and gran- ular carbon adsorption. IPC treatment is capable of removing 95-98% of the organics from municipal wastewater (Table IV). The product, containing 6-12 MG/L of total organic carbon, is suitable for reuse as a high quality irrigation supply, industrial supply or perhaps, even for body-contact re- creational purposes. The total operating costs for a 10-MGD IPC treatment facility are estimated to be $0.22/1000 Gal. which compares favorably with the cost of a conventional secondary treatment plant with phosphorus removal. Moreover, IPC treatment offers several distinct advantages over conventional primary and secondary treatment: Reduced land requirement — 1/4 to 1/2 of land area for conventional treatment. Greater flexibility in design and operation. Reduced sensitivity to diurnal flow and load variations. Immunity to substances toxic to biological systesm. A design manual on granular activated carbon adsorption presents pro- cess design guidelines, cost and performance information and discusses equipment considerations of interest to the design engineer such as mode of contacting (upflow, downflow, static bed, fluidized bed), materials of construction (concrete, steel), and mode of operation (gravity, pressure). A list of full-scale plants which will be using independent physical- chemical treatment is shown in Table V. Nitrogen removal capability can be incorporated into the treatment scheme of a physical-chemical plant by utilizing one of the recently- developed ammonia removal techniques such as breakpoint chlorinat ion, or 45 ammonia air stripping at elevated pH. The largest demonstrated nitrogen removal plant in the United States is the 3.5 MGD, cross-flow ammonia stripping tower at Lake Tahoe, California (Figure 7). Air stripping, when used in conjunction with lime precipitation of phosphates, is a relatively inexpensive physical-chemical ammonia removal technique which requires a capital investment of only about $700,000 for a 10-MGD facility. Total oerating costs for a 10-MGD plant are approximately $0.04/1000 Gal. Because large air flows (200-400 ft^/Gal) are required, the process is temperature- sensitive and freezing is an operational constraint limiting process appli- cation to warmer climates. In addition, the process not without operating difficulties because of the formation of calcium carbonate scale. Breakpoint chlorination is also a broadly-applicable alternative. This technique can produce an effluent with 0.5 MG/L of NH3-N from a feed concen- tration of 20 MG/L NH3-N at a cost of $0.04/1000 Gal. (assuming chlorine at 3C/lb) • The technique will increase the total dissolved solids in the ef- fluent, primarily chloride ion (7.6 parts CL/Part NH3-N) but will oxidize the bulk of the NH3 to N2 which does not represent a potential air pollution problem. The recent successful demonstration, at 2.5 MGD, of using high purity oxygen in the activated sludge process has the potential to significantly extend the utility of the current investment in activated sludge facilities and reduce the capital requirement for future plants of this type (Figure 8 and Table VI) . A conventional 10-MGD activated sludge plant will cost some $0,135/1000 Gal. to operate, including capital amortization. Cost reduc- tions of 15% or more appear to be attainable for new plants utilizing oxygen. Percent savings are portentially greater for conversion of existing over- loaded plants to oxygen. These cost savings are attributable to the reduced detention time required for the oxygen system to achieve BOD removal. In full-scale tests, for example, the oxygen system has achieved a 92% reduc- tion in BOD in a detention time of 2 hours compared to the 6 hours required by a conventional diffused air system. A list of full-scale plants which are being designed for oxygen aera- tion is shown in Table VII. Nitrogen removal can also be incorporated into a treatment scheme based on biological processes. A three-stage biological system has been developed which provides excellent process control for the attainment of high effi- ciency removal of carbon and nitrogen. This system, if augmented with chem- ical addition to the aerator, can provide control of both phosphorus and nitrogen nutrients (Figures 9 and 10; Table VIII) . Carbonaceous materials are oxidized in the first stage followed by nitrification of the ammonia in the second stage and denitrif ication in the third stage, a carbon source, such as methanol, is required for the third- stage denitrif ication. Over-all nitrogen removal efficiencies of 90% are obtainable. The incremental cost for achieving nitrification in a 10-MGD facility is between 3C and 4C/1000 Gal. and, for denitrif ication, between 4C and 5C/1000 Gal. Five full-scale demonstrations of this technology, at plant flows as high as 25 MGD, are expected to be initiated next year. While much new process technology has been developed for municipal pollution control applications, these same techniques are finding applica- tion in the areas of industrial, agricultural and mining pollution control. 46 Industrial Wastes Industrial wastes are, of course, highly diverse in nature. Industrial waste components include acids, alkalies, salts, nutrients, toxic materials, organic and inorganic solids, oil and grease and even heat. Even with re- gard to BOD, however, in the United States industrial wastes represent a greater BOD load than do all municipal wastes combined. the BOD^ population equivalent for U.S. industrial sources exceeds that of 400 million people. We are seeking to develop and demonstrate better methods of treatment and control for wastes from industry. Part of this goal, and a part of ever- increasing importance, is to develop closed- loop systems for recovery and reuse of the water in individual industrial processes or in industrial com- plexes. Under its industrial pollution control research program, the Environ- mental Protection Agency assumes part of the risk of developing new tech- nology and promotes and demonstrates improved methods for industrial pollu- tion control through a program of grants direct to industry. There are over 170 completed or on-going projects in this EPA industrial waste control demonstration program. It is beyond the scope of this paper to discuss progress in all of the industrial categories. Highlights of major accom- plishments are presented. When a beneficial use for waste pickle liquor, such as utilizing it for phosphorus precipitation from municipal wastes, is not economically practicable, the waste can, nonetheless, be treated economically. A tech- nique for treating the acid rinse waters produced by the HCL pickling of steel strip preparatory to cold rolling has been successfully demonstrated at a scale of 2.2 MGD. The acid rinse waters are neutralized by limestone and the ferrous iron is then oxidized to ferric iron in aeration tanks (Figure 11) . Polyelectrolytes are used to facilitate the sedimentation of the ferric hydroxide floe. The effluent from such a system is clear and of neutral pH but it still contains high levels of chloride (perhaps 1,000 MG/L) . The settled solids from the sedimentation step can be dewatered on a vacuum filter and disposed of by land fill. This treatment system costs about $0.20/1000 Gal. or less than $0.05 per ton of steel. This system should find increasing application in the United States in view of the trend of the steel industry to convert to HCL pickling. One of the most widespread and intractable problems of the chemical industry is phenolic wastes. Phenol is a serious problem because of its widespread occurrence, toxicity to many biological species and the waste it can impart to fish and other seafood. For the chlorobenzene process for the manufacture of phenols, a unique, closed-loop system for treating and recovering phenolic wastes has been demonstrated at one quarter of full- scale (Figure 12) . The effluent from the phenol production facility is passed through a steam stripper to recover benzene and acetone and is then cooled in a heat exchanger before being applied to two activated carbon ad- sorption columns in series. Phenol is removed in the -first column from (15-200 MG/L down to 4 MG/L) . The effluent is then acidified to a ph of 3 with HCL and then acetic acid is adsorbed on a second carbon column. Phenol and acetate are recovered from the carbon by chemical elutriation with caustic and are recycled for reuse. The effluent brine from the car- bon columns is also recycled as a feed stock for chlorine cuastic produc- tion. Final phenol concentration in the return flow is as low as 0.1 MG/L. 47 Not all forms of pollution are as invisible to the eye as the toxic effects of phenols. Some pollutants, such as color bodies are much more visually evident and are aesthetically unacceptable. Kraft pulping and paper making produce effluents with as much as 1,400 platinum cobalt units of color. Lime clarification of this effluent can achieve and 85-90% re- duction in color at a cost of about 36C/1000 Gal. (Figure 13) . This is equivalent to around $4 per ton of pulp processed. This cost could be sig- nificantly reduced if a system of recalcination, similar to that used to recover and reuse lime-phosphate sludges from municipal treatment plants, were developed. Developmental efforts are now underway. The development of alternative methods of sludge disposal is an essen- tial ingredient to providing "packaged technology. " Some recent and inter- esting applications of sludge recovery and reuse concepts have been devel- oped. The primary sludge from a pulp and paper mill plant, for example, can be dewatered on a pressure drum filter (technology borrowed from Europe) and used as (1) a supplemental fuel ("hog fuel") for conventional steam boilers, (2) a dry mulching material for highway slopes, or (3) an agricul- tural soil conditioner (Figure 14). In the food processing area, the peel, seeds and low-grade molasses wastes from a citrus juice concentrating plant can be dried, pellet ized and sold for as much as $80/ton as a cattle feed supplement. Moreover, the waste activated sludge from the biological treat- ment plant at this location is being dried and sold at $240/ton as a chicken feed supplement which is high in protein and vitamin B-12. The revenues from the sale of these "by-products" are more than adequate to cover the cost of the entire wastewater treatment plant. The demonstration plant at Winter Garden, Florida, is being expanded to meet the increasing demand for these "by-products" which has been generated by the local farmers. The disposal of sludge from an API separator (a unit developed by the American Petroleum Institute) , tank bottom sludge and spent caustic has always been a serious problem in the petroleum industry. Pit storage, burial and open burning have been partial and, frankly, unsatisfactory so- lutions in the past. A 70-barrel/day fluid bed incineration system for the treatment of refinery chemicals and oil sludges has been successfully dem- onstrated. The facility is actually a modification of a commercially-avail- able process which was originally designed to process sulfite wastes from the paper industry. At least three major oil companies in the United States are installing similar waste control facilities at several of their plant sites . The methodology discussed so far has focused on "treatment" as the pri- mary pollution abatement technique. Control of pollution at its source or control of water use are also important pollution abatement techniques. An excellent example of in-process control has recently been demonstrated in the canning industry. A dry, caustic peeling technique, capable of elimina- ting 90% of the water-use requirements and associated BOD from the peeling operation, has been demonstrated at full scale for potato processing and is now being evaluated for sweet potato and table beet processing. The pota- toes are dipped in a lye bath and transported on a conveyor, at a controlled speed to regulate the penetration of lye, to an infrared gas-fired burner. The burner bakes the peel off and residual flakes of peel are cleaned by a series of rubber-tipped rollers. The potatoes are then given a minimum volume high-pressure rinse as a final polishing step. Such a dry caustic peeler costs approximately $98, 000/Line (20,000 lbs/hr) compared to 48 $29,000/line for conventional peeling equipment. However, activated sludge treatment of potato wastes costs about $0.06/lb. BOD5 removed and, based on the reduced hydraulic and BOD load to the treatment plant and the savings in caustic and operating costs for the peeling operation, the dry caustic peeler will pay for itself in less than four months. There are over 15 in- stallations in the United States today using this technique with an addi- tional 35 on order. A modification of the dry caustic peeling technique which eliminates the infrared burner is being evaluated for the peeling of peaches, pears and apricots with the potential of reducing the water-use requirements by 95%. Peeling is, of course, only one step in food processing. The other two major water-use steps are transport and blanching. We have demonstrated, at 8.6 MGD, the treatment, recovery and reuse of beet transport water and are now evaluating various types of steam, hot water, microwave and hot air pilot blanchers in an attempt to reduce the water-use requirements for this operation by 50% or more. Agricultural Wastes Agricultural pollution includes nutrients from fertilizer runoff, salts and pesticides from irrigation return flows and BOD and solids from confined animal feedlots. Feedlot wastes are of increasing concern in the United States. The BOD5 from a confined animal production operation can range from 10,000-50,000 MG/L. To a large degree, the management techniques of confined animal feeding have increased the severity of the pollution problem from these sources by concentrating the wastes in local areas. One important approach toward solving the animal feedlot problem involves the techniques of housing or ar- ranging the animals in a manner which will minimize or eliminate the waste collection and transport problems. For example, a technique of caging hens and syspending them over an oxidation ditch has been demonstrated for a 250-hen operation (Figure 15) . The wastes are biologically stabilized in the oxidation ditch prior to land disposal of the sludge. The operation is superior to the alternative of dry conveyor collection both in terms of odor control and of producing a stabilized sludge. The cost of the oxidation ditch treatment is between 1£ and 4C per dozen eggs produced. An interest- ing observation has been that swine can be trained to walk over a separate slotted floor area to deposit their wastes directly into an oxidation ditch below (Figure 16) . The judicious placement of their food supply directly across the slotted floor from the pen area provides the needed inducement. Unfortunately, cattle are not quite so cooperative. Open feed areas with tight soil and proper runoff collection facilities can, however, provide adequate control. Loose soil and poor drainage are not only undesirable from a waste management standpoint, but also from a beef production perspec- tive. Cattle can lose 50% or more of their normal weight gain during the summer months by walking around in unconsolidated muddy soil. Several al- ternative collection systems are available for confined cattle feedlots. These include mechanical scrapers, slotted floors and sloped floors. Biologically stabilized feedlot wastes can often be disposed of by land spreading the sludge and spray irrigating the effluent (Figure 17) . Where the size of the operation or the local soil conditions preclude use of land disposal, advanced waste treatment nutrient removal techniques, 49 similar to those used for municipal pollution control, can be used prior to discharge. The nutrient concentration of animal feedlot wastes as for BODc, is significantly higher than municipal waste concentrations. For example, phosphorus concentrations as high as 110 MG/L AS P are not uncommon in poultry wastes. Chemical costs to achieve 80% phospherous removal from poultry wastes are $0.40 to $0.53 per 1000 Gal. for lime and alum respec- tively. Dosing requirements average almost 1100 MG/L for alum and 4,400 MG/L for lime. Lime treatment has the added advantage of providing superior color removal but increases the sludge handling requirements. Irrigation return flows are another significant source of agricultural pollution. The increase in silt and total dissolved solids is significant but the increase in nitrates may often be of special importance because of potential health effects in drinking water supplies. At Firebaugh, Cali- fornia, denitrif ication of irrigation return flows, by adding methanol and passing the flow through a coarse media upflow contactor, has been success- fully demonstrated. The nitrate concentration can be reduced from 25 MG/L to 2 MG/L. Application of this technique in the San Joaquin Drainage Basin, for example, would reduce the nitrate load to San Francisco Bay by 125,000 lbs per day. Denitrif ication technology utilized in municipal pollution control is similar. Other Urban Wastes The category, "Other Urban Wastes," includes storm and combined sewer discharges, urban runoff and unsewered municipal wastes. Other urban wastes have many of the same adverse effects on water quality and water use as mu- nicipal sewage. They contain high concentrations of bacteria, solids, or- ganics and inorganics. The primary difference between these wastes and municipal sewered wastes is their frequency and unpredictability of occur- rence and their variability in hydraulic load. Separation of storm and sanitary sewers, once thought to be the ultimate solution to the combined sewer problem, is of questionable applicability in many locations because of cost, physical disruption of normal urban activities during construction periods and the realization that even separated storm flows may have high pollution potential due to suspended solids, BOD and bacteria. One solution is to build optimized storm flow collection and treatment systems. Because of the intermittent nature and magnitude of flows typical of these wastes (1 to 100 times greater than dry weather flows) , the utilization factor of capital invested in facilities will be less than for systems where waste flows approach steady-state conditions. Techniques which are relatively lows in capital cost, in spite of relatively high operating costs, are pre- ferred for these applications. There is a real premium to be gained by using unit processes capable of high flow rates such as microstraining , fine screening, dissolved air flotation or high rate (20 GPM/FT 2 ) media filtra- tion (Figure 18) . For example, in Philadelphia, Pennsylvania, the potential utility of microstraining of combined sewer flows at 45 GPM/FT 2 was demon- strated. Microstrainers, rotary drum screens often used for algae removal in water treatment, have also been demonstrated to have real value for ter- tiary solids removal from treated municipal sewage. In fact, a 15-MGD facility is now under construction in Chicago, Illinois. Using a 23-micron screen, the suspended solids removal efficiency in this application has ranged from 62% to 96% and has averaged 80%. Volatile suspended solids 50 removal averaged 71%. Estimates of the cost of microstraining and chlori- nation (5 to 20 PPM dose) of storm runoff are on the order of $9,000 per MGD or $11,000 per acre of drainage treated. This cost, while high, is only 40-50% of the estimated cost of separating storm and sanitary sewers which has been estimated to be $20, 000-$23 , 000 per acre. Fine screening (297 microns) and dissolved air flotation with alum and polymer coagulation of combined sewer overflows was demonstrated at 5 MGD in Milwaukee, Wisconsin. Reductions of up to 98% suspended solids, 79% BOD and 92% of the phosphorus concentrations in the wet weather flow were mea- sured. The capital cost of this type of installation is about $12,000 per MGD of capacity (approximately $.01 per daily gallon) or $9, 000-$14, 000/acre, Operating costs are 3C-4C/1,000 gallons treated. Control techniques are also a very vital part of abating pollution from storm and combined sewers. Control techniques include the physical aspects of routing, diversion and containment of either stormwater or com- bined sewage (Figure 19) . In-line and off-line storage during storms with subsequent discharge to treatment facilities has merit and is an excellent way to improve the utilization factor of the capital investment in collec-' tion and treatment facilities. In Detroit, Michigan, a monitoring and re- mote control system is being demonstrated to maximize the storage capacity of the existing sewer system. New power-operated diversionary overflow structures and automatic control instrumentation have been installed to measure wastewater flow, quality, conduit liquid levels, and to control remotely diversion gate operations. Telemetering is provided to transmit and record data collected and to provide feed-back data relative to the status of the remotely controlled units. Another possible solution to part of the non-sewered municipal waste problem is being demonstrated at Grandview Lake, Indiana, and Albany, New York. Individual grinder-pumps have been installed in each house. Wastes are then discharged into small diameter, plastic pressurized sewers (Fig- ure 20) . The sewage from a small group of houses is collected and treated in a package plant. This kind of system may be applicable where distantly- separated homes or rock excavation costs make the construction of conven- tional sewers prohibitively expensive. Oil Spills Oil spill problems are related primarily to transportation activities since adequate overflow channels, secondary diking and alarm systems can readily be designed to minimize spills from stationary facilities. During the last several years over 150 million gallons of oil have been released in major spill incidents costing tens of millions of dollars to clean up, and the potential insults to the environment from accidental spills are increasing as ships get larger (16,000-30,000 DWT tankers in the 1950' s compared with 200,000-350,000 DWT tankers in the 1960's and 70' s) and as pipelines which have served us well in the past are getting older and fail- ing more frequently. A great deal of research effort in the United States is currently being focused on methods of containment (booms) , mechanical harvesting techniques (air, water, mechanical sweeps) , pickup, separation and disposal methods. A 30,000-Gal. per hr. oil skimming and separation system capable of producing a discharge water of less than 100 PPM and a recovered oil con- taining less than 5 percent water has been successfully demonstrated. The 51 oil content of the discharge water could be reduced to less than 20 PPM if required by recycling it through the centrifuge a second time. The skimming device is a twin-hulled barge with a partially louvered bottom appropriately baffled to attenuate wave action. Skimmed oil is collected by a floating weir and pumped to a centrifuge (4,000G) capable of handling inlet emulsion concentrations up to 5,000 PPM (Figure 21). The over-all system efficiency is 99% when operating at 0.5 knots and 80% at 5 knots under smooth sea con- ditions. The system will operate under conditions up to and including sea state 4 (moderate waves, wind velocity 20 knots, wave height 5 ft.), but with some loss in efficiency. This system, together with booms and an oil storage tank, constitutes a complete ocean oil spill recovery system (Fig- ure 22) . What can be done when an oil slick has already been washed on-shore and contaminated the beaches? Early attempts to clean contaminated beaches were often slow, tedious and expensive operations. A technique capable of clean- ing 4.5 miles of contaminated beach in one working day has recently been demonstrated. The beauty of the operation is that the equipment, or suit- able substitutes, is almost universally available for contingency spill clean-up operations. The equipment involves a grader, an elevating scraper and an imaginative systems approach (Figure 23) . The operator of the grader (modified with half-tracks to improve traction in the sand) starts his first pass furthest inshore with the moldboard set at a 40 degree angle with re- spect to the direction of travel. The last pass is made at the surf line with the moldboard angle changed 100° to reverse the direction of cast from seaward to landward. The elevating scraper picks up the resulting windrow (material deposited from the trailing edge of the grader blade) . The pro- cedure can be used to clean sections of beach 200-300 yards at a time. This is an excellent example of utilizing commercially-available equipment and reminding us that pollution control techniques need not be unique or novel, just effective. Another facet of the over-all pollution problem is the disposal of used motor oils. A system employing vacuum distillation and fractionation, capable of handling 9,000,000 gallons per year has been demonstrated during the last year and a half. The used crankcase oil provides No. 6 fuel oil (28.4%), No. 4 fuel oil (36.8%), No. 4 diesel oil (20.8%), No. 2 fuel oil (5.5%), gasoline additive (0.5%) and process fuel for plant use (5%). The remainder is water. The recovered products are supplemented with first grade materials at a cost of $0,003 to $0.24/Gal. to meet U.S. market spe- cifications for products which have a retail price of $0.05 to $0. 10/Gallon. Direct operating costs for the plant are $0.04/Gal. Changes in the oil industry to multi-grade motor oils with much higher additive contents and the trend of automobile manufacturers to greatly in- crease the mileage and time intervals between recommended oil changes has significantly changed the composition of crankcase oil in recent years. Pretreatment steps of centr ifugat ion , solvent extraction and chemical treat- ment will have to be incorporated to remove the spent and degraded addi- tives, sludge and tar-forming materials produced by piston blow-by. Since process changes are still being implemented to handle the more difficult feedstocks, accurate figures on future equipment requirements cannot be made at this time. At the present, however, the recovery and reuse of used motor oils appears to be marginally profitable. Process optimization to increase the yield of products with a higher resale value could improve the economics . 52 Mining Wastes Every year mining and related operations cause some 500 billion gallons of mine drainage containing millions of tons of acid and acid salts to de- grade over 10 thousand miles of surface streams and 15 thousand acres of impounded water in the Appalachian region of the United States. Several interesting procedures for abating acid mine pollution have been developed in the last two or three years. The first involves the use of a permeable plug to neutralize and seal acid mine drainage sources in one operation. Pulverized limestone is pneumatically placed in the mine portal to provide a contact time of appoximately 25 minutes* to effect neu- tralization of seepage (Figure 24) . Iron hydroxide (and possibly calcium sulfate) precipitated during this neutralization gradually fills the pores of the plug and seals the mine opening Field tests of this technique have indicated a reduction in flow from 7 GPM to 0.5 GMP in 55 days and the pH of the acid mine water was raised from 3.1 to 5.8. A finished seal in an actual mine with a 4-1/3' by 12* drift having 25 feet of roof contact and 36 feet of length on the base was placed at the rate of 850 pounds per minute at a cost of $3,048. The flow of 3 GPM has been essentially stopped and the plug is currently withstanding a hydrostatic head of 6.3 ft. Anal- yses indicate that the pH of the acid mine water increased from 3.0 to 6.9 with a simultaneous change from 300 MG/L of acidity to 160 MG/L of alkalin- ity. A potential breakthrough in mine drainage technology has recently been developed. The process, "Neutrolosis , " utilizes neutralization and reverse osmosis in combination. Mine drainage is pre-filtered and then passed through a multi-stage reverse osmosis unit The concentrated brine is neu- tralized with lime and clarified. The clarified effluent can be recycled and blended with the feed to the R.O. unit. This process recovers 98% of the drainage water, produces a sludge suitable for disposal by simple land- fill and completely eliminates the brine disposal problem. Over-all rejec- tion efficiencies of 97-98% have been obtained for calcium, magnesium, sul- fate, iron and aluminum along with 79% reduction in conductance and 82% reduction in acidity. Average water recovery for the R.O. unit was 91% at a water flux of just over 11 Gal/FT 2 /Day. A flux decline of less than 2 Gal/FT 2 /Day was noted in 100 hours of operation but the membrane fouling was not irreversible and could be controlled by rapid pressure changes and a flush cycle. Larger-scale, long-term evaluations are currently being made to determine membrane life and obtain accurate cost information (Fig- ure 25) . In addition to transferring technology we must all be on the look-out for technology from other disciplines which can be adopted for environmental protection. Our mine pollution control research program has, for example, looked to space technology for a possible answer. One very desirable way of attacking the acid mine drainage problem is to prevent the formation of the acid drainage in the first place. We are currently evaluating the con- cept of mining coal in an oxygen- free atmosphere. Miners are equipped with modified "space suits" complete with their own life support systems includ- ing an emergency rebreather, radio transmitter/receiver and an umbilical hose which is connected to either a portable rebreather or a fixed rebrea- ther-ciller module. The suit has three layers, an undergarment to absorb body moisture, a gas-tight middle garment and a heavy-duty outer work 53 garment. The mine, equipped with a gas lock curtain at the mine portal, is filled with inert gas, e.g., nitrogen or methane. Modification of existing conventional mining equipment will be minimal for such an operation The completed feasibility study indicates that the cost of equipping a 5,000- ton-per-day underground coal mine with inert gas blanketing would not in- crease the installed cost of the mine by more than 12%. In a non-gassy mine, the operating costs of inert gas operation may increase the operating costs of the mine by a few percent but in the case of a gassy coal mine, operation in an inert gas atmosphere may actually decrease the cost of the mine operation by as much as 20% when credit is applied for the methane gas that is collected and sold. While this mining concept must still be re- garded as in an exploratory stage, it holds substantial promise for ultimate practicability, especially considering the advantages in health (elimination of black lung disease) and safety (elimination of explosion hazard) which the approach may offer. Conclusion A variety of newly-developed, cost-effective treatment and control techniques are available to abate pollution from many major sources. Many of these techniques have already been demonstrated at full scale and are ready for wide-scale application. Many new techniques, which incorporate the very desirable aspects of by-product recovery and reuse, are also avail- able which can stimulate new industrial activities and change the economics of various product lines. Pollution control activities, in some instances, are even profit-making and resource conservation opportunities in addition to being an increasingly necessary part of man's responsibility to himself and his children to preserve the environment. Man has the ability to control pollution and future prospects for achieving a clean environment through technology transfer and imagineering are bright. Hopefully, history will record that in the same decade that man first reached and explored the moon he also realized the finite nature of the earth and its environment; that he "returned" to protect it and that he succeeded'. 54 REFERENCE MATERIAL The following Research, Development, and Demonstration Grant, Contract, and in-house project reports which relate to the subjects discussed are available from The National Technical Information Service, Department of Commerce, Springfield, Virginia 22151, (paper copies - $3.00 and $6.00, microfiche copies - $0.95) or at the Government Printing Office, Washington, D.C. 20402, at the designated sale price. Further inquir- ies concerning these reports should be directed to the Project Reports System, Office of Research and Development, Water Quality Office, Environmental Protection Agency, Washington, D.C. 20242. Report Number Title/Author Source 10000 04/70 Research, Development and Demonstration Projects — Division of Applied Science and Technology; by FWQA, Washington, D.C. PB 192 091 11000 01/70 Storm and Combined Sewer Demonstration Projects — January 1970; by Storm and Combined Sewer Branch, Division of Applied Science and Technology, FWQA, Washington, D.C. PB 190 799 11020EK010/69 Combined Sewer Separation Using Pressure Sewers; by American Society of Civil Engineers, Cambridge, Mass. PB 188 511 11023EV006/70 Microstraining and Disinfection of Com- bined Sewer Overflows; by Cochrane Div. Crane Co. , King of Prussia, Pa. GPO — 70* 11024 06/70 Combined Sewer Overflow Abatement Tech- nology; Storm and Combined Sewer Pollu- tion Control Branch, Division of Applied Science and Technology, FWQA, Washington, D.C. GPO — $2.50 12000 01/70 Projects of the Industrial Pollution Control Branch; by Industrial Pollution Control Branch, Division of Applied Science and Technology, FWQA, Washing- ton, D.C. PB 189 766 12000 07/70 Projects of the Industrial Pollution Control Branch, July 1970; by Indus- trial Pollution Control Branch, Divi- sion of Applied Science and Technology, FWQA, Washington, D.C. GPO — $1.75 55 Report Number 12060 10/69 12060 04/70 12060FAD10/69 13030ELY12/69 Title/Author Source Current Practice in Potato Processing GPO — $1.00 Waste Treatment; by University of Washington, Seattle, Washington. Proceedings First National Symposium on (at press) Food Processing Wastes; by FWQA, USDA, National Canners Assoc. , and Northwest Food Processors Assoc. Aerobic Treatment of Fruit Processing PB 188 506 Wastes; by Snokist Growers, Yakima, Washington. Collected Papers Regarding Nitrates in GPO — $1.50 Agricultural Waste Waters; by FWQA, San Francisco, California, U.S. Bureau of Reclamation, and California Department of Water Res. 14010DM003/70 14010DYK03/70 14010DZM08/70 14010EIZ01/70 15080E0S10/70-1 17010 01/70 17010DHT09/70 New Mine Sealing Techniques for Water GPO — $1.50 Pollution Abatement; by Halliburton Company, Duncan, Okla. Treatment of Acid Mine Drainage by GPO — 55 C Reverse Osmosis; by Rex Chainbelt, Inc., for the Commonwealth of Pennsylvania Feasibility Study of Mining Coal in an GPO — $1.50 Oxygen Free Atmosphere; by Island Creek Coal Co., Holden, W.V. and Cyrus Wm. Rice Div. , NUS Corp., Pittsburgh, Pa. Limestone Treatment of Acid Mine Drain- GPO — $1.25 age; by Bituminous Coal Research, Inc., Monroeville, Pa. Evaluation of Selected Earthmoving GPO — $1.50 Equipment for the Restoration of Oil Contaminated Beaches; by URS Research Co. , San Mateo, Calif. Treatment Techniques for Removing (at press) Phosphorus from Municipal Wastewaters; by J.J. Convery, Advanced Waste Treat- ment Research Laboratory, FWQA, Cin- cinnati, Ohio. Methanol Requirement and Temperaturre (at press) Effects in Wastewater Denitrif icat ion; by Gulf South Research Institute, New Iberia, La. 56 Report Number 17010DRD07/70 17010ED006/70 17020 12/68 Title/Author Source A Study of Nitrification & Denitrifica- GPO — $1.00 tion; by Aerojet General Corp., El Monte, Calif. Phosphorus Removal Using Chemical Coagu- GPO — 65 -l'lt».ui.'. l J''f-) I' I • \ "■•iK-il>J 'Vu\'i I ,1 iM''i ;/i W I, /•(',•'• ; WASH WATER EDUCTOR LUDGE WASTE SLUDGE Figure 4 65 C9 C_3 . 1 CARBON REGENERATION "111 i — i i CO CO CD ■ CD GO M ■H fa CD e/i 66 LU I— < _ lu Q- LU SrfLU LU /*■ ^ CO CO >- o o II D O O U L ■ ■ ■ ■ ■ ■ ■ {■■■■■■■■■■■•■■■l ■ ■■■■■■■■■■a ■ ■ ■ ■ a. ■ ,»,-■- JL&A AAA ■■ to u en ■H fa ivAOwaa % 3AiivnnwnD 67 k— -J» 1 - in Figure 7: Ammonia Stripping Tower at South Lake Tahoe , California 68 SCHEMATIC DIAGRAM OF MULTI-STAGE OXYGENATION SYSTEM AERATION TANK C0VER ^ AGITATOR GAS RECIRCULATION COMPRESSORS OXYGEN FEED GAS WASTE LIQUOR FEED RECYCLE SLUDGE EXHAUST GAS MIXED LIQUOR EFFLUENT TO CLARIFIER PRIMARY HIGH RATE C— C0 2 Al or Fe SLUDGE Figure 8 NITRIFICATION NH 3 — N0 3 SLUDGE DENITRIFICATION NO3— N 2 Al or Fe METHYL ALCOHOL SLUDGE THREE SLUDGE SYSTEM FOR NITROGEN REMOVAL SCHEMATIC OF THREE SLUDGES SYSTEMS FOR NITROGEN REMOVAL Figure 9 69 rdered to reduce its BOD5 by 87 percent (8) . Laboratory bench-scale tests •evealed that either activated sludge or activated carbon could achieve the •equired BOD5 removal and that each could assure high removals of oil and >henol. Therefore, bench-scale tests were conducted to develop design >arameters for alternative treatment systems. The use of these design larameters revealed that a sand filter, activated carbon, centrifuge sludge, lewatering system was more economical than activated sludge. This was due irimarily to space limitations in the refinery and the lesser space require- lents of the activated carbon system. The economics of the activated carbon ;reatment system justified the use of the new technology. However, in the :ase of another oil refinery in the same river basin the conventional ictivated sludge system proved to be the more economical and preferable ystem. A wood products plant had a highly-colored, high BOD5 effluent equiring about 95 percent BOD5 removal (9) . Because of anticipated future equirements on color removal, studies were initiated to determine the easibility of using bark and waste wood products for manufacturing activated arbon and then using the activated carbon for wastewater treatment. The .ctivated carbon could achieve the required BOD5 removal and could produce . substantially colorless effluent. However, the high activated carbon equirements and the new technology involved in activated carbon manufacture nd regeneration made the application of this new technology both uneconomical nd risky. Therefore, activated sludge was provided even though the treat- ent does not provide significant color removal. In this case, the waste ctivated sludge was very difficult to dewater. Bench-scale and pilot-plant est data indicated the technical feasibility and economic advantages of sing the new electrolytic cell type of sludge thickening. Although initial ull-scale operating results were disappointing, the equipment is now meeting ts performance guarantees. ollution Abatement The technology of pollution prevention is not new. The first draft of manual on the subject for the petroleum industry (in behalf of the American etroleum Institute) was prepared by the author nearly 20 years ago. Although he basic concepts are not new, it is believed that a new technology is merging for industrial pollution control. This new technology is predicted because of: Higher costs for waste control due to more restrictive regulatory requirements on all aspects of environmental protection (water, air, and land) and escalating construction and operation costs. 85 2. The possibility of Federal law that will require a detailed evaluation of the potential impact of waste materials on the environment prior to approval of construction and/or operation of facilities manufacturing new products. 3. The possible establishment of raw waste and effluent standards for different manufacturing process operations based on a standard of "good practice" such that those producing raw waste greater than that of "good practice" must provide a higher degree of effluent treatment to meet the effluent standards and those producing raw waste less than that of "good practice" may provide a lower degree of effluent treatment to meet the effluent standards. Higher pollution control costs, the likelihood of more stringent pollution control requirements, and possible incentives for in-plant control of pollution are each forcing more industries to look at the entire pollution generation-effluent treatment system rather than at effluent treatment alone. In the case of new facilities, the escalation of the costs of handling, treating and disposing of process losses and by-products from practically nothing to a very significant positive value is changing the economic criteria controlling the details of industrial process and plant design. The emerging new pollution prevention technology will be based on the following concepts : 1. Minimize process losses and by-product formation at the source. 2. Maximize the recovery and reuse of those product and by-product losses that cannot be eliminated. 3. Provide effluent treatment only for that which can be controlled or handled in no other way. The ultimate objective of preventive measures is the establishment of a closed loop system producing no wastewater discharge. Several industries in the United States have recently achieved this objective (10). The wood products plant, referred to earlier, has conducted its pollution abatement program in accordance with the above concepts. Today they are recovering and marketing materials that just a short time ago created serious water pollution. Most industries will be unable to achieve the closed-system objective; however, all have the potential of significantly reducing pollution by preventive measures. The various preventive (i.e., in-plant) measures that can reduce pollution are: 1. Process design modifications, (e.g., overall economics vs. unit operations economics; continuous vs. batch processing; loss-control devices; reagent substitution; surface condensers vs. barometric condensers) . 2. Recovery and utilization, (e.g., downgraded use of chemicals; product recovery and reuse) . 86 i. Engineering design considerations, (e.g., water conservation; waste segregation; used-water recycle; leakage control devices and systems) . [. Local equalization, pretreatment , or disposal. i. Operation control, (e.g., automatic vs. manual control). ). Good housekeeping, (e.g. , employee relations programs) . Industry is in a unique position in that it has numerous and varied ilternatives available for solving its pollution control problems. It has uch alternatives because it has control of its system from source to isposal. Industry can control what it produces, where it is to be produced, ,he process that it uses for production, the manner in which it handles its rocess losses and by-products, the reliability of process and mechanical esigns, and how it handles and disposes of its wastes. Thus, industry may hoose to minimize pollution control costs by being selective about the ocation for its plants or special processes. It may choose to control ollution at its source by choice of basic process, by choice of continuous s. batch processing, by loss recovery and recycle, by by-product utilization, r by special process and/or mechanical designs. It may choose to simplify r minimize costs by segregating wastewater streams, by utilizing separate ewerage systems, by providing used-water recycle systems, by equalization, r by pretreatment. It may control losses by providing operational aids and y enforcing good operation practices. It may choose to treat and dispose f its wastes utilizing its own on-site facilities, or it may utilize a ublic system. The kind of pollution control facilities provided depends on the nature f the problem, the permissible quality of the effluent, and the required eliability of performance. The best system can be evolved only if the nterrelationships of the entire system, including the manufacturing facili- ies, are properly considered and evaluated. It must be remembered that air ollution control may result in a water pollution control problem and that he correction of the water pollution control problem may create either an ir pollution or water pollution problem, and so on "ad Infinitum." Thus, the potential for the development of a new technology for ndustrial water pollution control should be apparent. In order to identify the potential of pollution reduction by one or ore of the measures above, it is necessary to conduct detailed in-plant urveys to identify the source, quantity, quality, mode of occurrence, and ariability of wastewater sources. The in-plant studies for the Humble Oil nd Refining Company at their Baton Rouge, Louisiana, refinery (11) is a pod example of the kind of program needed to accomplish in-plant pollution ^eduction objectives. Pollution prevention at the source is not as well adapted to sanitary jastewater as to industrial wastewaters. However, the conversion of "hard" lynthetic detergents to "soft" biodegradable detergents is equivalent to eagent substitution for industrial processes and indicates the trend of he times. 87 Environmental Protection The technology of Environmental Protection can be enhanced significantly if current trends in the United States continue. These are the development of new technology for integrated river basin water quality management and im- provement in the technology of governmental pollution control administration The development of objectives, goals, and tasks and of master plans for both immediate and long-range implementation for inter- and intra-state river-basin agencies show considerable promise for optimizing the use of water resources in the United States. Preliminary studies (12-16) have es- tablished a methodology for evaluation of alternatives and indicate that there is, in fact, a least-cost regional or basin solution to the water quality preservation problem. The more widespread use of this emerging new technology may be universally beneficial. The administration of pollution control law must be reasonable, equit- able, and credible. The deficiencies of past practices in this regard are being recognized. Reasonableness, for instance, is demonstrated by requir- ing only that which is attainable and enforceable. Equity is demonstrated by establishing and enforcing policies such that each polluter bears his fair share of the burden of attaining and maintaining clean waters. Credi- bility is demonstrated by persistently and consistently enforcing that which is attainable and enforceable. The reasonableness, equity, and credibility of enforcement is intimately related to the technical aspects of pollution control. Therefore, the ad- ministrative policies should be carefully considered and clearly defined so that their technical relationships can be understood and uniformly applied by all administrators. Some States in the United States are preparing comprehensive adminis- trative manuals to assure consistency in administration of enforcement policy (17) . Those who pass new legislation and those who must administer pollution control law should carefully consider the fundamental concept of incentive There should always be incentive to control pollution as close to its source as possible. There should be incentive, other than drastic shut-down of operations, to abate rather than create pollution. It is believed that the incorporation of new pollution control technol- ogy in process design and control is essential to attain and/or maintain desired water quality. Therefore, the development and use of new technology should be encouraged. There is no substitute for knowledge of fundamentals, for the experi- ence and skills required to apply that knowledge, and for sound judgment in the incorporation of new pollution control technology in process design and control. Nevertheless, the availability of a methodology for minimizing the risk in incorporating new technology should encourage the development and use of such new technology. The concepts and guidelines discussed herein have been very useful to the author in incorporating new technology in process design and control. It should be understood that the specific steps to be undertaken and the thoroughness of the effort should be controlled by the magnitude and com- plexity of the project. It is hoped that these concepts and guidelines will be helpful to others and in doing so will stimulate progress. 88 References 1. Roy F. Weston. "The Role of the Consulting Engineer in Introducing Technological Innovation in Water Pollution Control." Proceedings, 17th Southern Water Resources and Pollution Control Conference, University of North Carolina, Chapel Hill, North Carolina, 1968. 2. Robert K. Shaw and J. H. Dougherty. "Generation of a High Quality Effluent at Whippany Paper Board Co., Inc." Presented at 6th TAPPI Water and Air Conference, Jacksonville, Fla., April 1969. 3. A. F. Thompson and D. M. Whitney. "A Comparative Evaluation of Two- Stage and Single-stage Activated Sludge Processes". Presented at the Conference of Texas Water Pollution Control Association, Houston, Texas, July 1970. 4. W. F. Milbury, C. H. Hawthorne, and D. McCauley. "Operation of Conventional Activated Sludge for Maximum Phosphate Removal". Presented at the 43rd Annual Meeting of the Water Pollution Control Federation, Boston, Mass., October 5-9, 1970. 5. "Phosphate Study at the Baltimore Back River Wastewater Treatment Plant" Water Pollution Control Research Series, 17010DFV09/70, Contract No. 14-12-471, Environmental Protection Agency, Water Quality Office, Wash. , D. C. 6. Roy F. Weston, V. T. Stack, Jr., A. F. Thompson, Jr., and R. A. Evangelista. "Automatic Control of the Activated Sludge Process". ISA Transactions, 9 (l):22-7, 1970. 7. Roy F. Weston, Inc. "Combined Sewer Overflow Abatement Alternatives for Washington, D. C." Report for the Water Quality Office, Environ- mental Protection Agency, Wash., D. C, August, 1970, Contract No. 14-12-403, Program No. 11024-EXF. 8. P. Krishnan, R. F. Peoples, and R. N. Simonsen. "Use of Sand Filter Activated Carbon System for Refinery Wastewater Treatment". Presented a the 26th Purdue Industrial Waste Conference, Lafayette, Ind., May 4-6, 1971. 9. P. H. Woodruff and W. C. Parsons. "Pollution Control—Conservation, Recovery and Treatment." Presented at the 6th TAPPI Water and Air Conference, Jacksonville, Fla., April 1969. .0. Closed Loop Water Treatment Systems—Material Presented by the Johns- Manville Corp., Owens Corning Fiberglas Corp., and Certain-Teed Products Corp. in competition for The Sports Foundation, Inc. 1970 Gold Medal Award. .1. D. S. Diehl, R. T. Denbo, M. N. Bhatla, and W. D. Sitman. "Effluent Quality Control Program at a Large Oil Refinery". Presented at the 43rd Water Conference of The Water Pollution Control Federation, Boston, Mass., October 1970. 89 12. Roy F. Weston, Inc. "Tocks Island Region, Environmental Study." Report for Delaware River Basin Commission, April 1970. 13. Roy F. Weston, Inc. "Water Quality Report, Miami River Basin, State of Ohio." Report for Miami Valley Water Quality Committee, Dayton Area Chamber of Commerce, February 1967. 14. Roy F. Weston, Inc. "Oswego River Basin Water Quality Management Study. Report for New York State Conservation Department, Division of Water Resources, April 1969. 15. Roy F. Weston, Inc. "Feasibility and Implementation Report, Advanced Wastewater Treatment." Report for Neshaminy Creek Basin, June 1969. 16. Roy F. Weston, Inc. "Feasibility of Joint Treatment in a Lake Watershed. Published by FWPCA, Department of the Interior, DAST 17, Program No. 11060 FAE, Grant No. WPRD 66-01-68, November 1969. 17. J. F. H. Walker, et al. "Guidelines for Implementation Control of Wastewater Discharges." Report for State of Wisconsin, Dept. of Natural Resources, March 1971. 90 o o CO • f PETROCHEMICAL PLANT VARIABILITY OF WASTEWATER BOD, 3000 2500 2000 1500 1000 500 2 5 10 20 30 40506070 80 90 95 98 PROBABILITY OF OCCURRENCE OF OBSERVED VALUE EQUAL TO OR LESS THAN GRAPH VALUE Figure 1 PETROCHEMICAL PLANT VARIABILITY OF BIOLOGICAL TREATMENT RATE .0100 z s O z UJ .0010 .0001 20 30405060 70 80 90 95 98 PROBABILITY OF OCCURRENCE OF OBSERVED VALUE EQUAL TO OR LESS THAN GRAPH VALUE Figure 2 91 PHOSPHATE REMOVAL IN FULL-SCALE ACTIVATED SLUDGE WITHOUT CHEMICAL ADDITION 25 20 10 TEST SECONDARY EFFLUENT — <^^ COMMON PRIMARY EFFLUENT^ ••• \ • \ ••• k 1 • 1 • 1 • •* 1 L *\ * ••'■* J • *• ft * *. 1 9 • 1 CONTROL ** I SECONDARY J EFFLUENT^ A J L • •• i • * I •• • i I L* 1 * \ * ' ' 1 TEST DISSOLVED \OXYGENt o xoX°°x''ift°x°xox\ * am m mm ^7 o »^»c tTBfcif n*n r ^1 » o "oXoXoXS^fci^^ 11/11/69 11/12/69 11/13/69 11/14/69 TIME HOURLY SAMPLES Figure 3 100 S 70 BO 50 0.5 1 2 5 10 20 30 40 50 60 70 80 90 95 98 99 99.5 PERCENT OF OBSERVATION EQUAL TO OR LESS THAN GRAPH VALUE CONTROL ACTIVATED SLUDGE SYSTEM PHOSPHORUS REMOVAL VARIABILITY Figure 4 92 EVALUATION OF NEW WATER POLLUTION CONTROL TECHNOLOGY By Walter A. Lyon Director, Bureau of Sanitary Engineering Department of Environmental Resources Commonwealth of Pennsylvania, USA Government has a primary responsibility to correct environmental injur- ies and plan for a wholesome environment. This is why it must play a key role in evaluating and advancing new water pollution control technology. Pollution problems are largely due to technology which is planned and land development which is allowed to proceed without considering environmental effects. This means that government also has a role to help reshape tech- nology so as to make it more harmonious with nature. This paper touches on recent improvements in water pollution control technology that have shown promise, and then discusses government's role in evaluating and reshaping technology. Industrial Wastes Coal Mine Drainage --Recent revisions in Pennsylvania's water pollution control law which placed drainage from coal mines on the same regulatory basis as other kinds of industrial wastes has resulted in the construction of treatment facilities to reduce pollution from coal mine drainage Lime treatment for pH adjustment, precipitation, aeration, and clarification are used in order to remove acidity and iron from mine drainage. State standards require the discharge contain no net acidity and a total iron con- tent of less than 7 mgle. Table I shows performance data concerning five typical plants. Some mine drainage treatment systems use novel approaches. In search- ing for neutralizing agents less expensive than lime, some mine operators have turned to limestone. But, the ferrous ion in the mine drainage pre- cipitated on the limestone, coating it and rendering it inactive. To over- come this problem, the limestone chips were placed in horizontal rotating cylinders which provided sufficient attrition to keep the limestone "clean. " Where lime is used as a neutralizing agent, significant quantities of unreacted lime appear in the sludges. To eliminate this waste and reduce chemical costs, some mine operators have begun recirculating sludges. Re- circulation of sludges works very well and has an added benefit of concen- trating the sludge. Typical solids concentration in non-recirculated sludges is about 5% by volume. The concentration of solids in recirculated sludges is about 30% by volume. In some locations treatment plants are used to neutralize the entire flow of streams which had been polluted by acid and iron discharges from abandoned coal mines. On the North Branch of Slippery Rock Creek in Penn- sylvania the entire stream is passed through a treatment plant (during periods of normal flow) for neutralization and clarification and in other ceases, lime feeding equipment is installed over the stream and lime is 93 discharged directly into the stream. The precipitate is removed in earthen basins. Water Pollution from Solid Wastes Disposal — The increasing attention to the environmental effects of solid waste disposal has led to the finding that many solid waste disposal sites cause water pollution, particularly ground water pollution problems' 2 ^. Sanitary landfills using earthen cells which surround the compacted refuse are used frequently. In a number of instances collection and treatment of leachate from sanitary landfills is re- quired in order to allow the use of the landfill site. In some instances synthetic membrane liners for the landfill are required in order to inter- cept and collect the leachate. Spray Irrigation — Spray irrigation as a means of organic industrial waste disposal is being practiced widely^ ''. It has been highly success- ful where careful consideration is given to soil characteristics, hydroge- ology, vegetation, and spray field management in order to prevent surface and ground water pollution. The fertilization characteristics of some waste effluents has provided a substantial supplement to cattle pasture productivity. Pulp and Plating. Wastes — The activated sludge treatment process has been important in the successful treatment of pulp and paper mill wastes (5,6. and phenolic wastes. In the management of plating wastes, the development of integrated systems where wastes are treated at the source has been found increasingly successful'''"^. These systems minimize the need to discharge heavy metals from plating plants and have been effective in reducing pollu- tion from this source. In these systems chemical are added to rinse waters as a part of the process allowing for more extensive reuse before rinses are exhausted and sent to the waste water treatment system. Pollution Incident Prevent ion --In spite of the application of wide- spread successful industrail waste treatment practice throughout Pennsyl- vania, there continue to be a significant number of pollution incidents caused by human, maintenance, or operational failures. In order to prevent this problem, the state has implemented a Pollution Incident Prevention Program which requires industrial plant management to study production and waste management systems in order to make sure that plant design, opera- tional procedures, and personnel training programs designed to anticipate and prevent pollution incidents ^ 9/ *- ' . The study and report required of each water-using industrial plant must include an analysis of possible accidents which might occur during transportation, storage and processing of raw materials, intermediate, and finished products, materials and fuels(H). The possibility of breakdown of treatment plant equipment must be considered. The plan must include a program of routine inspections and preventive maintenance, personnel train- ing, procedures for minimizing damage from possibe pollution incidents and an analysis of past pollution incidents. Experience so far has shown that 1/3 of the pollution incidents during the past five years in Pennsylvania were caused by production process failures and not treatment systems fail- ures . Deep Well Disposal — The disposal of wastewaters in deep wells has' 12 ^ been practiced on a limited basis and found to present many problems. Pre- treatment costs and system maintenance are expensive and some wells have already been abandoned. 94 Sediment Control — There is an increasing amount of interest in sedi- ment control from construction and agricultural operations. Technical and government program methods are being developed and have been quite success- ful in some instances (13 , 14) > Municipal Wastewater Treatment Tertiary Treatment — Increasing water usage and population growth in and around urban centers have made it necessary to provide tertiary-level treatment, particularly in cases where municipal sewerage systems discharge to small high-quality streams. In many instances, tertiary treatment is necessary, not only to reduce the organic wasteload on the streams, but also to remove phosphates from the effluent of the wastewater treatment plant to control the growth of aquatic plants (15 , 16) < Eighty percent (80%) phos- phate removal is required in a number of instances throughout the state. Chemical treatment with lime or alum for phosphate coagulation with clari- fication is the most common process used. Detroit, Michigan plans to use pickling liquors from a nearby steel mill as a coagulant Aerobic Digestion — Waste activated and increasingly primary sludge, aeration, has been adapted from package plants to provide for more nuisance- free solids disposal (1°» 1") Larger plants, such as Denver, Colorado and the Hyperion plant at Los Angeles, are currently practicing aerobic sludge digestion to soluble-ize approximately 40% of the sludge solids with a waste liquor that can be effectively reprocessed. Tube Settlers — The installation of tube settlers in existing clarifiers has been found quite successful in improving the efficiency and capacity of clarification systems (20) . The Use of Polymers — Chemical polymers have been used successfully as coagulant aids in wastewater treatment processes, particularly in cases where existing treatment efficiency both in terms of BOD and suspended solids removal needed to be upgraded significantly. In most cases, experi- ments with various types of polymers was necessary in order to select the ideal polymer for the specific treatment plant. Polymers have also been found successful for increasing the carrying capacity of sewers. Plastic Media — The use of plastic rather than stone media in connec- tion with trickling filters has allowed significant economies and savings in space when installed in specially designed units and has in some in- stances increased efficiency of existing filters. Spray Irrigation — Experiments with spray irrigation of secondary ef- fluent has been successful (21) . The success of the process is largely due to suitable soil and geologic conditions which provide significant bacter- ial action and exchange capacity for the removal of phosphates and other pollutants. The process has resulted in enhancement in growth rate of forest and agricultural crops as well as providing recharge of local ground water. Joint Treatment — Joint treatment of industrial wastes with domestic wastewaters has gained increasing favor. In some treatment plants the in- dustrial waste load exceeds the municipal waste load. When such combina- tion of treatment is being applied, careful analysis is necessary in order to determine the effect of the industrial waste on the collection system and the wastewater treatment process. Pre-treatment prior to discharge to the sewage system is necessary in the case of some wastes. 95 Plant Operation and Waste Load Monitoring —Increasing attention is being given throughout the United States to operator training and certifi- cation as the expertise of the operator is crucial to the success of the waste treatment process. Twenty-seven states now have mandatory operator certification and twenty more have voluntary programs. Many treatment plants have become hydraulically and organically over- loaded as a result of rapid urban and industrial growth. Increasing em- phasis is being placed on careful monitoring of waste load trends arid advance planning to provide needed conveyance and treatment plant capacity on a timely basis. Water Pollution Control Systems Techniques — The use of modern systems techniques has greatly enhanced water pollution control practice in the United States (22) _ Systems techniques are now used in the simulation and modeling of treatment plant design and assimilative capacity of estuaries and streams. Data systems to improve state-wide water pollution control management are being used and ex- panded in Pennsylvania, Michigan, New York and an increasing number of states. Government water pollution control programs can primarily be viewed as information processing efforts. The methods used to handle this information are usually antiquated and as a result there are significant delays in re- sponding to pollution problems. Pennsylvania is in the process of carrying out a demonstration water quality management information system research and development project under the sponsorship of the Environmental Protection Agency which is designed to overcome these defects and use modern systems techniques in the management of water pollution control programs (23 , 24) t Figure 1 shows the systems modules which are in the process of being de- signed, programmed, and implemented. The shortest response time between the recognition of pollution prob- lems in a major water body and its solution is between fifteen and twenty years. Adequate forecasting systems should shorten this response time in the future to prevent interim degradation. Most waters remain polluted because of this long response time. Comprehensive water quality management information systems will greatly enhance the speed and precision with which decisions may be made in the water quality management field. Such systems provide the water quality man- ager with current and accurate data and permit forecasting of water quality problems and the execution of "before the fact" preventive actions or plans. In Pennsylvania it recently became necessary to manage 200 miles of river on a real-time basis (25) # ^ sudden release of impounded water from an abandoned coal mine resulted in the discharge of 150 tons of acid per day into the West Branch of the Susquehanna River. By use of mobile labor- atories equipped with radio communcations , state water management personnel were kept in constant touch with water quality conditions. They were able, by the addition of lime and sodium hydroxide at various river stations and management of dam releases, to effectively manage the quality of the river over a period of six months, preventing serious water quality degradation. The Role of Government in the Development of New Water Quality Management 96 Technology While the historical role of government in water pollution control has been in the regulatory field, it is essential that government also provide an important stimulus for developing and implementing new technology by mak- ing known research needs and funding research programs and projects (26) . one of the regulatory functions is the review of engineering designs of collec- tion and treatment systems. In carrying out this review function, standards based on existing technology are established and used which are usually quite conservative to assure soundness of investment and performance. At the same time, government has a continuing responsibility to evaluate new technology and modify standards as adequate pilot and prototype data become available. Problems often arise when someone proposes a new untried process and hopes to experiment with public (non research) funds to determine its feasibility. In Pennsylvania we have taken the postion that research and demonstration funds should be used for purposes of experimentation, but we have occasionally found that the proponents of new concepts have wanted to experiment with the funds of municipalities which were in the process of de- signing a sewage treatment plant in order to abate pollution. We have per- mitted such experimentation as long as the experimenter is willing to bear the financial risk of the experiment by placing funds into escrow which might be needed to convert the process to a conventional process should the experiment fail. Under this policy, a number of new processes have been developed. The Role of Production and Service Technology in Pollution Control One of the major reasons for the increase of pollution problems in in- dustrialized countries is that production and service technology have been allowed to develop with minor, if any, consideration given to their effect on the environment. The imposition of pollution control on production pro- cesses will often cause changes in production technology designed to mini- mize pollution problems. Many industries are learning to recycle their wastes to minimize the use of water and to recover or reuse materials which are previously dis- charged in the form of pollution. An outstanding example of such a pro- duction change has been the complete revamping of the pulp and paper pro- cesses at the Hammermill Paper Company in Erie, Pennsylvania. At the cost of approximately $30 million this plant changed its process to increase production of pulp by 50% and (at the same time) reduce by approximately two-thirds its organic and color waste loads. As a result of this change the Hammermill Paper Company will be sending its reduced waste load to the City of Erie Sewage Treatment Plant for treatment where the municipal wastes will provide the nutrients necessary for treatment and the treatment process provides for a very high degree of treatment prior to discharge to Lake Erie. As pollution control programs expand and affect an increasing number of industries, it is likely that we will see similar responses in industrial production and service technology in industrialized countries. The Need to Blend Water Pollution Control, Production, Service Technology, and Land Use Planning and Control The Waste Impoundment Problem — Unless water pollution control activi- ties are conducted in harmony with industrial and urban needs they can 97 generate their own adverse externalities by creating new forms of pollution problems. One example is the rapid growth of waste impoundment lagoons as a result of Pennsylvania' s water pollution control program. Between 1937 and 1970 Pennsylvania' s industrial waste control law and program were geared to eliminate pollutional discharges . While this program has been quite suc- cessful in eliminating a great deal of fisible pollution from our surface waters, it did result in the growth of lagoons throughout Pennsylvania to the point where we now have approximately 2,000 of them. Many contain toxic chemicals, petroleum products, and other substances that may either cause ground water pollution or surface pollution incident hazards. A number of these waste impoundment structures have recently failed and caused serious pollution incidents. One such failure caused pollution of approximately 50 miles of the Allegheny River and another lagoon containing wastes recently failed causing oil pollution along 35 miles of the Schuylkill River and 13 miles of the Delaware River. The 1970 amendment to Pennsylvania's law has now allowed the state to initiate a program to eliminate these hazardous lagoons. This will make it necessary for many industrial processes to be modified to minimize the production of toxic or otherwise harmful wastes or else provide for a more satisfactory process for treating them. The Effect of Municipal Wastewater Charges — The imposition of charges for industrial wastes discharged to municipal sewer systems has in some cases been helpful in modifying the processes used within an industry which have produced wastes. In any case, industries should be expected to bear their fair share of the cost of handling their wastes in municipal systems and where a significant share of plant capacity is reserved for any indus- trial plant, financial protection must be provided in the event the indus- try moves or ceases to use its portion of the system. Waste Load Control — The state has recently imposed sewer extension and connection bans as a result of the uncontrolled expansion of sewer systems which result in overloaded treatment plants and hence more pollution. This is a new form of land-use control related to the control of pollution. Bans on sewer connections and extensions have been imposed on sewerage sys- tems tributary to treatment plants which have become overloaded. In order to prevent this problem in the future, each Pennsylvania municipality has been asked to submit an annual report showing organic and hydraulic waste load trends. When the plant is within five years of reaching its capacity, the municipality must submit a schedule showing how it will proceed to provide the needed additional capacity within five years. If such a sched- ule is submitted, approved, and adhered to, additional extensions and con- nections are allowed — otherwise a ban is imposed. Regional Systems — The state now has the authority to consider the es- tablishment of regional wastewater management systems in the issuance of permits for sewage and industrial waste systems. A great deal of fragmen- tation in waste treatment has occurred because water pollution control programs have in the past emphasized the abatement of pollutional discharges Increased attention is now being given in the United States and Canadian provinces to the regionalization of waste collection and treatment sys- tems (27) . This will result in improved economies, more efficient use of facilities, better supervision and service, and greater harmony with water use requirements. Such systems should be planned considering water supply and water development needs jointly and should support and enhance economic and social plans for the region. In order to control the fragmentation of 98 waste management problems and reduce the response time between the issuance of orders by the state and construction of pollution abatement facilities by municipalities, the state is now considering legislation which would allow it to install and, if necessary, operate wastewater treatment facil- ities in the case of municipalities that do not wish to build them. These facilities will be financed by user charges in the same manner as locally constructed municipal systems. Water pollution technology is rapidly growing to meet the challenge of a more wholesome and pleasing environment throughout our nation. Inasmuch as technology is largely the cause of pollution problems, its intelligent and discriminate application can and will eliminate and prevent pollution problems of the future. 99 REFERENCES 1. Heine, Walter N. and Giovannitti, Ernest F. — "Treatment of Mine Drain- age by Industry in Pennsylvania" — Journal of Sanitary Engineering Divi- sion, ASCE, Vol- 96, No. SA3 (June 1970). 2. Hughes, G.M. , R. A. Landon and R. N. Farvolden — "Hydrogeology of Solid Waste Disposal Sites in Northeastern Illinois" — Progress report to De- partment of Health, Education and Welfare on Demonstration Grant No. 5-D0100006-02, prepared at Illinois State Geological Survey (1968). 3. Flower, W.A. — "Spray Irrigation — A Positive Approach to a Perplexing Problem" — Proceedings 20th Purdue Industrial Waste Conference, 679 (1965). 4. Parsons, W. C. --"Spray Irrigation of Wastes from the Manufacturer of Hardboard" — Proceedings 22nd Purdue Industrial Waste Conference, 602 (1967). 5. Gillespie, W. J. — "Recent Paper Industry Waste Treatment Systems" — Journal of Sanitary Engineering Division, ASCE, Vol. 96^, No. SA2 (June 1970) • 6. "Joint Municipal and Semichemical Pulping Waste Treatment" — Federal Water Quality Administration, 11060 EOC, WPRD 223-01-68, Washington, D.C. (1969). 7. Lancy, L. E.--" Integrated Treatment for Metal Finishing Wastes" — Journal Water Pollution Control Federation, Vol. 26, 9, 1117 (1954). 8. Schreur, N. — "The Lancy Integrated System for Treatment of CN and Chromium Wastes in Electroplating Plants" — 22nd Purdue Industrial Wastes Conference 310 (1967). 9. Lazarchik, D.A. — "Pennsylvania's Pollution Incident Prevention Pro- gram" — Proceedings 25th Purdue Industrial Waste Conference (1970) . 10. Dawson, G. W. , Shuckrow, A. J., Swift, W. H. — "Control of Spillage of Hazardous Polluting Substances" — Environmental Protection Agency, Washington, D.C. (1970). 11. "Industrial Waste Manual" — Bureau of Sanitary Engineering, Pennsyl- vania Department of Health, No. 14, 27 (1970). 12. Manning, J. C. — "Deep Well Injection of Industrial Wastes" — Proceed- ings 23rd Purdue Industrial Wastes Conference, 655 (1968). 100 McCullough, C. A. — "Control of Water Pollution During Dam Construc- tion" — Journal Sanitary Engineering Division, ASCE, Vol. 97, SA1 , 81 (February 1971) . Powell, M. D. , Winter, W. C. , Bodivitch, W. P. — "Community Action Guidebook for Soil Erosion and Sediment Control" — National Association of Counties Research Foundation, Washington, D.C. (March 1970). Nesbitt, J. B. — "Phosphorus Removal — The State of the Art" — Journal Water Pollution Control Federation, Vol. 41, 5, 701 (May 1969) Part 1. Spiegel, M. , Forrest, T. H. — "Phosphate Removal: Summary of Papers" — Journal Sanitary Engineering Division, ASCE, Vol. 95, No. SA5 , 803 (October 1969) . Remus, G. J. — "Management of the Detroit Metro Water Department" — Journal Water Pollution Control Federation, Vol. 43, 1, 17 (January „ 1971) . Smith, A. R. — "Aerobic Digestion Gains Favor" — Water and Wastes Engi- neering, Vol. 8, No. 2, 25 (February 1971). Randall, C. W. , Koch, C. T. — "Dewatering Characteristics of Aerobically Digested Sludge" — Journal Water Pollution Control Federation, Vol. 41, R215, Part 1 (May 1969) . Culp, G. L., Hsiung, K. , Conley, W. R. — "Tube Clarification Process, Operating Experiences" — Journal Sanitary Engineering Division, ASCE, Vol. 95, No. SA5, 829 (October 1969) . Parizek, R. R. , Kardos, L. T. , Sopper, W. E. , Myers, E. A., Davis, D.E., Farrell, M. A., Nesbitt, J. B. — "Waste Water Renovation and Conserva- tion" — Penn State Studies No. 23, Pennsylvania State University (1967). Proceedings, National Symposium on Data and Instrumentation of Water Quality Management, Water Resources Center, University of Wisconsin, Madison, Wisconsin, p. 2 (July 1970) . Murdock, G. B. — "A System Approach to Water Quality Data Management" — Proceedings, National Symposium on Data and Instrumentation of Water Quality Management, Water Resources Center, University of Wisconsin, Madison, Wisconsin, p. 57 (July 1970) . "Report on Comprehensive System Design for Water Quality Management Information System" — Price Waterhouse Co. , Philadelphia, Pennsylvania (June 1970) . Sawin, H.S. — "The CPA* s Role in Restoring the Ecological Balance" — American Institute of Certified Public Accountants, Management Adviser, 23 (Mar-Apr. 1971) . 101 25. "The Battle to Save the Susquehanna" — Pennsylvania's Health, Pennsyl- vania Department of Health, Harrisburg, Vol. 31, No. 4, 21 (Winter 1970) . 26. "A Strategy for a Livable Environment "--Report to the Secretary of Health, Education and Welfare by the Task Force on Environmental Health and Related Problems, Superintendent of Documents, Washington, D. C. (June 1970) . 27. Cleary, E. J. — "Institutional Innovations for Water Quality Manage- ment" — Journal Water Pollution Control Federation, Vol. 42, 2 157 Part 2 (February 1970) . 102 Water Quality Management Information System (system modules) Reports data and analysis of past, present, and projected water use. Information file on field and lab analyses of samples. Compares sample results to performance and stream standards. Reports data on single pollution incidents such as fish kills and complaints. Figure 1 10 3 A CO W CO >H Si 00 J ^D < CTi U rH H 2 01 w w E CQ u o E-i Eh U a O M < 1 ^ I W 04 tf ►H w 3 Eh m H g w S E-< Eh O4 < W a w Eh >h W w >. O 05 < O £ CO H a -p c h O H •tf CO in (1) CO ^D CN 00 O O CN CO ro c-H P 3 . • • • • • • • • • • • T3 • ro C rH co cn m 000 ■^ O HO O O rH O 0000 C ^~. id m rH < CN rH tO 5-4 , rH m S S 1— 1 ^D ^f rH CN U d> 04 W P P + ■— 1 P S3 C -H rH -p p ro co C G m m C^ -Tj< 00 O ^ n CJ (U fd p X> O CO in CN V£> CN O O U3 rH 00 mo b rH m < H H p p 1 rH >i (D P P ■rl -H 'O rH P ■H -H c ^ O ifl O t rQ rH P (U OJ ^ ro rH m m P. rH C 3 • • • It! • • • • 3 -H CN tO rH a> co co in in OOO CO O O rH O O O rH O +J _E rH

in in OOO cn 00 O O CN O X a; rH m < < in m CO "HH rH in v£> rQ H p p rH P. (0 <* C 04 ^ rH g 4-> • ro m cn CO Q> rH to 3 • • • • • • CO SH O4 SH rH CO r^ ^ r^ 0) tr 0) m rH CD p in cn r^ ^0 cn 00 r^ cn O ro OOO (0 +j C 3 • • » • ■ (0 tO rH LTl r^ m ■* -h; O O O O H r~ co cn O m CO co u rH MH r-\ CN CO O CTi O 00 CD < P , 0) rQ (0 ^- 01 ^ T3 P > T3 tc ft CO w P C -H H ID H to rH -H SH rH c •H T3 co (0 ft P p H C 5 10 rQ r^ ^t U •H O 3 0J rH Eh CO CO Eh CN + < ffi 0) -H X ffi rH O 3 O cn C rH C H^ 11 HI p U (0 CO u < .. 04 ft E- a, < CO Eh CO S N < S S O4 fa b-i W Eh § crcaid AH0J.VH03YT 10 3B o u I I 3 w w CO < CD < CTi U r-( M s « w w m m u o En U O I I Oh OS w e-i « a s w w s Eh Eh >h W W £ O PS !=> CO H S g CD i-H P T> --. c O O 00 o o 00 o C P P CD C 3 CO O O oo m o o o o o m O O O tO CD U P (0 rH i£> <7> vD (*■» * o >1 p CD **-\ rH CN 4J -H in H -H c 3 e -p •P CD co o m r- O -p *-* c (0 fO 3 P <-t >£> co r- ^0 -h- O .» to rH CD MH rH CN X TJ Hi < C ft -H H rH •P ft co CN CD -P 0) • c X r-H CD rt o m O O in o CD rQ fO p eg 55 3 h o m CTi "tf 00 o o o O O 00 O rH O i — 1 TJ MH i£> r- in vD ^D o o o o o CO O O CN O O ^0 O O vO O 0> i—i C C rH in in >x> O v£> in rH <; r^ P P H CN O rH T3 -P CN 00 in oo ft C C 00 CN V£> 00 o o a) -P CD co m oo CN CO c d • • • i o o O O O ^r o o rH O O rH o O O 00 o e - fO rH ijO in o r^ ^f r» rH ^D 00 o CN rH P Oi Oh 4H + rH CN en T3 W •r-l fO ^t r-l H rH U P ■iH -H • CD e -p N -P CO CO ijO CN CN c S3 -r-i C • • a . • • C 0) rH CD 1JD rH CO r~ CN 00 CN H p c m 3 P rH rH O U3 T3 CO fO p m + CD CD rH 3 MH CO cr )H CU Q< T3 -p X *- c O o in o CU -P CD i>d co m rH ^f co o in oo rj< UO rH rH 01 c d • • • • CU P fO rH CO rH <7\ ro o o o o o o -* H 00 H O O li)H O O 00 o P 3 rH *P rH CN O 00 O CO -* oo rH (0 P 0H C CN o o rH fO M 1 rH CN CO u P i CD A e -p OS 3 TJ P > TJ tO (0 w P Oi ■rH P C CD ■ rH p - Eh (0 > C -rH rH CD rH fO to ^ PJ p rH q ■rH T3 CO fO ft -P -P a CO 5 X ollution resulting from inhabitants, provided natural chlorides contents of •he receiver is known. 115 ORP potential. The value of this potential depends on the concentratior of either reducing or oxidating agents. ORP measurements in surface waters lead to the evaluation of the degree of their pollution with substances of reducing properties, which with simultaneous determination of other para- meters — iron being the most important—becomes a measure of the concentratior of reducing organic compounds. Among the latter are aldehydes, ketones, amines and unsaturated hydrocarbons. On the basis of numerous studies '■*-' ■** 12, 13, 19, 31) ^ t y ias ;b een found that ORP calculated for pH 7 is equal to 400 - 500 mvolt for clean surface waters. It follows from 1969 all-year studies at the automatic water quality monitoring station on Odra river at Wroclaw cross-section that ORP was equal to 250 - 420 mV. This would indicate, with simultaneous low concentrations of iron, the presence of reducing organic substances. Physical and chemical parameters of water are presented in form of daily variations graphs. From these graphs maximum, minimum and average values are evaluated for all water parameters. In case of observing significant changes in water level within a given day the flow rates will also be evaluated — corresponding to these levels--and they will be assumed for further computations. Thus obtained maximum, minimum and average values are compiled. From the knowledge of maximum, minimum and average daily concentrations and f lows--average, maximum and minimum loads are evaluated. Data from daily reports form a basis for monthly compilation of concentrations and loads of pollution. Due to the technical difficulties each parameter is presented in a separate table. Results from AWQMS may be also processed taking into account character- istic periods depending on rate and time of flow, water temperature and course of ice-cover phenomenon and state of water pollution. Generally, following characteristic periods are assumed: a. Summer period including months: July, August and September when usually low water levels and low flows occur, with high temperatures and intensive oxygen utilization processes. b. Winter period including months: January and February when ice- covers stops reaeration completely and low temperature of water does not favor self-purification. c. Autumn period including months: October, November, December — when the river is subject to pollution from seasonally operating factories of such industries as sugar, distilleries, starch industry, etc. d. Spring period including months: March, April, May and June when high water levels and flows are observed — favorable conditions for the river. For impounded rivers periods connected with the methods of utilization of the water course may also be taken into account, e.g. e. Navigation period including months: March, April, May, June, July, August, September, October and November --when river is impounded. 116 f. Post-navigation period including months: December, January, February when the river is not impounded and inland navigation is not going on. The navigation period may also be subdivided into periods of spring, summer and autumn navigation. It follows from the above that choice of characteristic periods depends on various factors and is connected with natural features of the drainage area and climate and with the hydrotechnical characteristics of the given stream. Elaboration of data from the AWQMS for the period of year is performed on the basis of individual monthly reports from which for individual months observed highest, average and lowest values are selected. On the basis of data contained in the annual report compilation of characteristic concentrations is made for a' given year. Frequency histograms. Characteristic concentrations presented above define extreme and average water quality in a river, giving however no evidence as to the frequency of their occurrence and their duration. Thus., ithey do not characterize the hydrologic and sanitary conditions of a stream iand its catchment. Frequency of occurrence of concentrations of individual quality para- meters and their duration result from hydrology characteristics of the stream, rhythm of hydrologic phenomena, heterogeneity of municipal sewage and industrial wastes discharges to the stream and from the varying intensity of 'self-purif ication processes in the reach above the monitoring station. Frequency computations and time duration graphs for individual parameters callow for comparison of changes of water composition in various years and observation periods. Frequency of these concentrations is presented in tables according to the hydrologic principles^ 4 '. Range of variations of concentrations in the period of time is sub-divided into equal compartments depending on the kind of parameters. For chlorides — for example, in case of Odra river at Chalupki, the compartments assumed were equal to 25 mg/1. Chlorides frequency curve is presented in Fig. 7. Heterogeneity of the frequency curve indicates that water composition is not only under the influence of hydrologic phenomena but is the result of heterogeneity of wastes discharges to Odra river. From the frequency computations one can easily construct a time- duration curve, presented in Fig. 8 which the statisticians call a summation frequency curve. Time-duration curves of individual parameters allow for drawing conclusions concerning possibilities of water utilization on the reach below the monitoring cross-section. In case of having turbidity and color measurements one may easily assess the number of days in the year when chemical precipitation is needed for color or turbidity removal. Moreover this relationship allows for assessment of annual cost of chemicals required for water purification, taking into account known dose of the coagulant. If the natural water composition has been deformed by wastewater discharges located above the monitoring cross-sections, then on the basis of time-duration curve of color concentrations or turbidity one may easily assess compensation that should be paid to those located along the down- 117 stream reach of the polluted river. Similar conclusions may be drawn in case of water intakes for municipal and cooling purposes. The knowledge of the time-duration curves for calcium and magnesium acid carbonates or calcium and magnesium sulphates and other compounds contained in water, will allow for assessment of relative costs of water softening in a given period. From the above relationships one may also conclude whether the construc- tion of the water softening plant is purposeful for a given industrial plant. If, for example, it follows from the curve that time duration of high hardness water within a year is only 10 days, then the softening plant is certainly not needed at all. Time-duration curves of water temperatures may be helpful in the design of water intakes for cooling cycles in industrial plants. Suspended solids time-duration curves should allow for deciding on expediency of construction settling taks prior to filters at water treatment plants . Method for computing and interpretation of waste loads. Full characteri- zation of water pollution required computations of loads of pollutants. Com- putations of daily loads passing a given monitoring cross-section are made as for concentrations. Finally, characteristic loads are obtained and plotted as needed. Determination of relationship between the concentration of pollutants and flow. Determination of relationship between the rates of flow and concentra- tions of studied pollution parameters, i.e.: chlorides, conductivity, turbiditi ORP, dissolved oxygen and parameters from the expanded programs of AWQMS is based on statistical regression analysis. The regression curve allows, by means of extrapolation or interpolation, for evaluation of the indicative con- centration on the basis of observed concentrations for a whole range of flows, Indicative concentrations obtained this way are more impartial than those cal- culated according to any method which takes into account only part of the observations . Summary and Conclusions As a result of studies conducted within fellowships abroad and time con- suming research conducted in the Water Pollution Research Laboratory WERI in Wroclaw a method for processing and interpretation of data from automatic water quality monitoring stations has been elaborated. The method is based on initial processing of data from W-20 monitors and particularly on evaluation of daily values of concentrations and loads: minimum, maximum and averages, anc characteristic values of concentrations and load in the period of month, year and in characteristic periods. Elaboration of data for the annual period of observation is based on establishment of characteristic concentrations and loads of individual pollution parameters and on preparation of frequency histograms, time-duration curves of these parameters and pollution loads, and curves of summary loads as well as relationship between concentration of pollution parameters and rate of flow. Results of studies for individual years and for individual cross-sections controlled by AWQMS are published in form of hydrochemical annual reports. These annual reports contain: description of the program of studies and analytical methods, description of automatic equipment with check-up data on each sensor, general hydrologic characteristics in each AWQMS cross-section and results of interpretation of the data. An example of the annual report prepared for the Odra river at the 118 halupki cross-section is Mahczak's paper entitled: "Degree of water pollu- ion in the Odra river at Chalupki monitoring cross-section— in 1960" ( 23 > . References Allgeier, R. J., Hafford, B.C., Juday, C, Oxidation-reduction potentials and pH of lake waters and of lake sediments. Trans. Wis. Acad. Sci. Arts Lett., 33, 115 (1941). Bee S., Manczak H. , Murawski T., Final Report on Study Tour to the United States, Great Britain, France, German Federal Republic, Sweden and Denmark, Sept. 30 - Nov. 8, 1969. Within "Poland oo26" Project — typed copies at the UN DP Project Of f ice— Warszawa 1969, and WHO Copenhagen. Deevey, E. S., Limnological studies in Connecticut and New York lakes, Ecol. Monogr., 11, 413 (1941). Debski K., Hydrologia kontynentalna. Wydawnictwa Komunikacyjne. Warszawa 1955. Federal Water Pollution Control Administration, STORET SYSTEM — Training Manual. Washington 1968. Florczyk H., Studies on the state of pollution of Upper Odra and Wisla rivers by means of automatic water quality monitoring stations. Interium Report on Theme 1.4.4.: Physical-chemical studies by means of instrumental analysis. WERI--Water Pollution Research Laboratory-- Wroclaw (English summary) . Florczyk H. , Comparison of water quality in Odra river in years 1964 and 1967. Gospodarka Wodna, 1969, No. 6. (English summary) Florczyk H., Study on location of automatic water quality monitoring stations. WERI--Water Pollution Research Laboratory—Wroclaw, typed copies, 1969 (English Summary). Hoak R. D., Bramer H. C, Natural sediment as factor in steam pollution control. Sewage and Industrial Wastes 28.311.1956. Hock B., Determination of flow and quality correlations by means of electronic computer. VITUKI Budapeszt 1966. Husmann W. , Vorf lutf ragen chemisch gesehen. Die Beinhaltung der Gewasser-Vortrage der Arbeitstagung der Fachgruppe Bauwesen im NSBDT — Archiv fur Wasserwirtschaf t des Reichverbandes der Deutschen Wasser- wirtschaft des Reichverbandes der Deutschen Wasserwirtschaf t, 1941. Hutchinson, G. E., Deevey, E. S., Wollack, A., oxidation-reduction potential of lake waters and its ecological significance. Proc. nat. Acad. Sci., Wash., 25,87 (1939). 119 13. Hutchinson, G. E. : A Treatise on Limnology. J. Wiley Sons, Inc., New York, 1957. 14. Internationale Kommision zum Schutze des Rheins gegen Verunreinigung . Bericht uber die physikalisch-chemische Untersuchungen des Rheinwassers| 1967 No. 2. 15. Jarmolinska K. : Sprawozdanie z wyjazdu stazowego do Niemieckiej Repub- liki Federalnej w ramach stypendium Swiatowej Organizacji Zdrowia. Maszynopis w Instytucie Gospodarki Wodnej we Wroclawiu. Wroclaw 1968. 16. Kolaczkowski St., Jankowski A., Kostrzewa E. : Rzeka Odra. Instytut Gospodarki Komunalne j , Zaklad Badawczy w Poznaniu. Poznan 1960. 17. Kolaczkowski St., Kniat J.: Rzeka Lutynia i jej doplywy. Prace In- stytutu Gospodarki Komunalne j, 1959 Nr 13. 18. Kredba M. , Knybel F. , Sole J. : Navrh ceskoslovenskych ekspertu na spusob prepostu koncentrace znecistenii z jistenych primyi merenimi na koncentracepri prutocnem mnozstui 355 denni vody. Maszynopi, Praha 1961. 19. Kusnetzow, S.J.: Microbiological researches in the study of the oxy- genous regimen of lakes. Vash. int. Limn. Ver., 7,562/1935. 20. Manczak H. : Zastosowanie metody statystyczne j do oceny stopnia zani- eczyszczenia wod rzecznych na podstawie wynikow periodycznych badan wody w przekroju pomiarowo-kontrolnym. Prace Instytutu Gospodarki Wodnej 1963, torn II, zeszyt 2. /English Summary/. 21. Manczak H. : Einige Merkmale der Selbstreinigungsvorgange als Grundlage der Gewasserklassif izierung . Fortschnitte der Wasserchemie und ihrer Grenzgebiete, Heft 6, Akademie-Verlag Berlin, 1968. 22. Manczak H. : Uber die Auswertung von Gewassergute Untersuchungen. Vom Wasser XXXV, Band 1968. 23. Manczak H. : Stopien zanieczyszczenia wody rzeki Odry w przekroju pomiarowo-kontrolnym w Chalupkach w roku 1960. Prace Naukowe Instytutu Inzynierii Sanitarnej i Wodnej Politechniki Wroclawskie j . Nr 2, 1969. 24. Manczak H. : Przebieg procesu samooczyszczania rzek skanalizowanych na podstawie kryterium tlenowego i wynikow badan rzeki Odry. Prace In- stytutu Gospodarki Wodnej 1970, torn VI, zeszyt 1. /English Summary/. 25. Meinck F. : Darstellung der Wassergute fliessender Gewasser durch gute- pegel und Profile. Kleine Mitteilungen fur die Mithlieder des Vereins fur Wasser-Boden und Lufthygiene. 18 Jahrgang No 1/3. 1942. 26. Natermann E. : Das Gutedauerbild. Die Wasserwirtschaft 40. Jahrgang No. 11. 1950. 120 7. Novotny V.: Ke korelacni zavislosti kvality vody w tocich na prutoku. Vodni hospodarstvi 1966. No 9. 8. Ohio River Valley Water Sanitation Commission. ORSANCO — 1967. Nine- teenth Yearbook — Cincinnati 1967. 9. Ohio River Valley Water Sanitation Commission. ORSANCO — 1968. Twen- tieth Yearbook—Cincinnati 1968. 0. Oleszkiewicz J./1968/: Final report on WHO fellowship to the United States. WERI — Water Pollution Research Laboratory—Wroclaw, typed copies — Wroclaw and WHO Copenhagen. 1. Pearsall, W. H. , Mortimer, C.H. : Oxidation-reduction potentials in waterlogged soils, natural waters and muds. J. Ecol., 27,483 /1939/. 2. Petru A. , Kredba M. : Priklad prpoctu hodnot koncentrace znecisteni zjistenych primymi merenimi merenimi na rece Odre w profilu Chalupki, na koncentrace pri prutocnem mnozstvi 355 denni vody. Maszynopis. Ministerstwo Rolnictwa, Lesnictwa i Gospodarki Wodnej. Praga 1961. 3. Popel F. , Hunken K. : Der Lastverteilungs plan und die Gutedauerlinie der Gewasser. Das Gas- und Wasserfach 1957, z. 36. 4. Praca zbiorowa: Stan zanieczyszczenia rzek w Polsce. Opracowanie syntetyozne. Wydawnictwo Arkady, Warszawa 1965. 5. Stangenberg, K. : Sklad chemiczny wod rzecznych na Dolnym Slasku. "Kosmos" Seria A, t. LXVI , rok 1948-1951, z. IV. 6. Stangenberg, M. : Stanzanieczyszczen wod biezacych dorzecza Odry. Zeszyty Naukowe WSR, Wroclaw, Zootechnika III. 1957. 7. Stangenberg, M. : Ogolny opglad na sklad chemiczny wod rzeoznych Polskie Archiwum Hydrobiologii 12/25/1964, Nr 1. 8. Tarasiewicz, W. , Surowiec, S. , Rybicki, Z. : Prawo wodne. Wydawnic- two Prawnicze, Warszawa 1965. 9. The Yorkshire ouse and Hull River Authority, Second Statutory Annual Report for the Period ended 31st March 1967. 121 Table I Example of Monthly Report on Water Quality in Ohio River at Stratton Cross-Section, February 1968 Parameter Maximum hourly value Average maximum value Average monthly value Average minimum value Minimum hourly value % value below per- missible Dissolved oxygen mg O2/I 15.26 13.93 11.22 7.17 7.02 100 Temperature °F 38.5 37.5 35.2 32.7 32.0 100 pH 6.99 6.89 6.56 6.26 6.01 100 Conductivity m /cm/2 5°/ 425 420 299 246 228 100 Chlorides mg CI /l 70 70 46 19 9 100 Rate of flow ft3/secxl000 - 160 51 13 - 100 122 Table II Definition and Nomenclature of Water Levels, Rates of Flow, Concentrations and Characteristic Loads No. Definition Symbols used for determining: Height xx/ Rate Concentration Loads of of stage of flow of pollutants mg/1 Pollutant g/sec 1. Highest from the highests HHH HHF HHC HHL 2. Average from the highests AHH AHF AHC AHL 3. Lowest from the highests LHH LHF LHC LHL 4. Highest from the averages HAH HAF HAC HAL 5. Average from the averages AAH AAF AAC AAL 6. Lowest from the averages LAH LAF LAC LAL 7. Highest from the lowests HLH HLF HLC HLL 8. Average from the lowests ALH ALF ALC ALL 9. Lowest from the lowests LLH LLF LLC LLL 10. Indicative - ALF JS JL 11. Permissible - - PS PL xx/ According to Debski's systematics the sign HHH denotes water level highest from the observed highest, while symbol HHF denotes flow rate highest from the highest. In this paper similarly, for denoting highest concentration from the highest symbol HHC is used to denote highest load symbol HHL. 123 400 350 3 300 O a 250 c o TO E 200 150 c o 100 90 80 364 355 270 180 90 30 -time duration of flow, days 99.64 97.18 73.91 49.21 24.63 8.21 0. -time duration of flow, %% correlation standard ■— — ^— limits of extreme values of concentration total median interval medians O extreme values Fig. 1. Correlation between time-duration of flow and concentration ot pollutants. (18). TYPE II TYPE III Fig. 2. Basic types of curves representing concentration of pollutants and rate of flow type I - for heavily polluted rivers type II - for clean rivers type III - for intermediately polluted rivers. 124 704 60 50 40 30 20 - 10 - _ RIVER ODRA AT CHAIUPKI 1967 VO-10°C = 213. 9 +8.2 x V1M5°C = 182.2 +6.2 y=15°C =70.8 +8. S x 0-10°C 11-15°C 7-15°C 20 40 60 80 100 120 140 160 180 200 220 240 Fig. 3. Relationship bilwun BOD5 and rat* of flow in Odra F,ow m3 />« c rivers at Chalupki, taking into consideration the effect of temperature 10 9 8 M 7 " * 0) E 5 m ^ 4 D 3 2 1 OLAWA RIVER AT OLAWA 1965 0.1144x y=1.8630e Fig. 4. Relationship between BOD5 andflow in Ola- wa river, with no ac- count for temperature 12 3 4 5 6 7 8 9 10 11 12 Q m 3 /sek 125 60 50 10 RUHR RIVER AT WILDHAUSEN ROK 1966 t% • • Fig 10 20 30 40 50 60 70 80 90 100 Qm 3 /sek 5. Relationship between BOD5 and Flow in Ruhr River at Wildhausen /GFR/ ° 100 I RIVER CALDER AT KIRKTHORPE 1966/67 • 20 •\ V = 88.2-4960 > 1 1 1 1 1 1 1 Ux 1 , RIVER AIRE AT LEEDS BRIDGE 100 1966/ 67 80 IT* 60 \ y= 94.3- 3022 40 ^— X 20 l 1 I 1 1 ._. W Hi . - RIVER ODRA AT CHALUPKI 1967 • •• " 10 «• •*••»■ I |TT II -9 c 8 c 7 -2r * • •• " #\ • • • • o> 6 • *y>fw» • >. 1 5 - J PV\*« • • • ■v 4 Lw • *\ • 1 y y= 100- 86.7 > 3 2 2 » • • X 1 X - * J- 1 1 —1 1 L-J 200 400 600 800 Flow m. g. d. 100 200 300 400 500 Flow m. g. d. 20 40 60 80 100 Flow m3/sec Fig. 6. Relationship between dissolved oxygen content and flow , for rivers with different caoarities for reaeration: Calder and Aire (Great Britain) and Odra (Poland) 126 Monitoring cross-section CHALUPKI River ODRA Year 1968 250 225 1 200 <_> >s 175 O) E c 150 o 'SZ 125 c 41 100 C o /5 41 -o 50 25 3 / the range of chlorides' concentration variations 1 1 i i i E 21 1" 40 172 M ill» most freqi of chloric! in I 75 21 o o w 20 40 60 80 100 days ig. 7. Frequency of occurrence curve of chlorides con- centrations in Odra river at Chalupki, 1968. Monitoring cross-section CHALUPKI 600 300 30 suoo 200 CO E 200 c o o O100 River ODRA Year 1968 a- time duration curve of chlorides concentration b- time duration curve of chlorides load c- time duration curve flow average annual Cl-concentration average annualflow 100 200 300 days 50 Fig. 8. Time duration curves of chlorides concentration loads and tlow in Odra river at Chalupki, 1968. 100% 127 THE PREVENTION AND CONTROL OF WATER POLLUTION IN ROMANIAN SOCIALIST REPUBLIC By eng. Mihai Lazarescu National Council of Water eng. George Rusu National Council for Science and Technology To prevent and control water pollution is one of the steps present soci ety is required to take and to develop, in order to limit man's endangering his evironment through demographic and economic development. This develop- ment requires the use of increased quantities of water supplied almost en- tirely by surface and underground sources of fresh water, which are known to be of a limited, not very large quantity and unevenly distributed on earth. Parallel with the decrease of available water supplies is the increased danger of ground and underground water pollution, due both to the ever- increasing quantities of wastewaters and to the complex substances they in- clude. Under these conditions, it is obvious that in Romania one of the most important problems of environmental protection is water pollution prevention and control. Our country, deeply committed to social and economic develop- ment, has to face particularly difficult problems in the field of water pol- lution prevention and control, as a result of the increased demands by agri- culture, industry and population, of the increasing quantities of wastewater discharged and of their high toxicity as well as of the spreading on the groups of larger quantities of fertilizers and pesticides. Water pollution is also increased by a reduction in the dilution flow of the water courses as a consequence of increased use of water. In our country, both the quantitative and qualitative aspects of water resource management are considered and dealt with so as to satisfy them adequately. A systematic concern in water quality control made it self particularly visible in the last 10 years and resulted in a series of administrative, technical and juridical measures meant to remove the causes of pollution and abate it. As a first step, general information on actual water quality and on its causes was obtained and we got acquainted with the methods more experi- enced countries are using to prevent water pollution. In 1963, taking as a basis this information, special legislation was adopted to prevent further pollution. This legislation laid the basis for co-ordinated endeavors aiming to gradually provide wastewater treatment plants and to ensure their proper operation. Steps have therefore been taken to carry out research and de- sign work for the facilities required in wastewater treatment, to reduce quantity and toxicity of trade effluents by in-process techniques, to work out standards and standard-designs, and to use the reclaimed effluents as well as the sludge originated in these wastewaters in agriculture. Research 128 md control institutes, training of specialized personnel and directions to coordinate water quality control within the different industrial ministries ire other achievements in the same direction. Simultaneously, special leg- slation was adopted which established penalties in the water pollution field. In this relatively short period since legislation was adopted, efforts j/ere directed in carrying out both the implementation program of wastewater treatment plants and in preventing pollution by in-process techniques so as :o reduce toxicity of wastewater. The efforts required a substantial co - zribution by the research and design institutes. These institutes for water management work within the National Water Council but research has also been provided by laboratories working within Ihe industrial ministries in their special fields. The institutes of hy- Ijiene, belonging to the Medical Science Academy and attached to the Health jlinistry are deeply concerned in public health and environmental protec- lion connected with water use and pollution. The Universities also develop brograms of research in this direction. Researches so far in water quality protection and wastewater treatment lave had the following main objectives: To determine the evolution of water quality of the main hydro- jraphic basins in our country, by studying their physico-chemical, biologi- cal and bacteriological characteristics. To study the natural phenomena of self-purification which contri- outes to improved polluted groundwater quality. To establish correlations between water quality and organisms (Living in water; to study the sources of toxicity to fauna and flora and the jLimits of toxicity for certain pollutants; to establish some biological characteristics for the waters of our country; to determine the proper nethod of analysis for different pollutants at concentrations found in watercourses and establish their toxicity. To work out the principles concerning mean organic wastewater discharges into watercourses, under the special conditions of our country. The studies and research done on the main hydrographic basins in Ro- nania have led to a knowledge of the groundwaters of our country (from the water quality point of view) to their classification (from the qualitative standpoint) to working our programs for multiple use of the hydrographic Dasins in Romania, as well as to developing lines of the water protection activity. Thus, e.g. evaluation of water quality in a river course at the intake point takes into account dilution and self-purification processes and the leed to satisfy properly the water user, as well. Therefore, the ground- waters, in term of users, have to correspond to one of the three quality categories for which quality characteristics were established. Other research done or in progress is concerned with the influence chemical fertilizers, pesticides and agriculture and sylviculture have on water. The multiple use of hydrographic basins and the construction of reservoirs have required research on the eutrophication and the most effi- cient methods for its control. Special consideration has been given to the protection and pollution control of Black Sea waters concerning both the discharge of industrial and domestic wastewaters from the different communities of the litoral. 129 Research regarding treatment of wastewaters aim at: Supplying the necessary parameters for the design of treatment plants, by determining the flow and the physico-chemical characteristics of wastewaters, their diurnal variation in flow and composition. Establishing the treatment techniques and the design parameters for treatment plants facilities by checking treatment processes on models, at laboratory, pilot or full scale size. Working out instructions and standards on discharging conditions of industrial wastewaters into town sewers. Studying a possible use for irrigation with municipal wastewaters! Improving the construction of wastewater treatment facilities, including improvement of aeration and use of more economic and efficient media for biofilters. Using new coagulants, extracted from industrial wastes (metallur- gical slag) for water clarification, etc. The investments involved in the last decade in abating water pollution amount to more than two thousand million lei ($100 Million) , while the num- ber of operating wastewater treatment plants increased from 400 to over 1,400. The measures taken to construct and ensure proper operation of indus- trial and domestic wastewater treatment facilities are developing in para- llel with measures taken to control pollution at its source. The effort to reduce wastewater quantity and toxicity resulted in reuse of coal processin effluents, reuse of rinse waters from sugar factories, recovery of useful substances from wastewater, such as fibers from pulp and paper mills, non- ferrous metals from the metallo-chemical plants, oil residue from distil- leries, ferrous sulphate from pickling processes of iron and steelworks, and lanolin from wool rinse waters. Wastewaters from some pulp and paper mills and fiber building board factories are recovered by extracting forage yeasts. Some toxic reagents are replaced by less toxic ones, e.g. phenol re- agents in mining processing. In oil extraction processes, underground salt water injection has been extended as a method for wastewater discharge, while in distilleries water use is being substantiall reduced, in order to facilitate treatment. Wastewater treatment is designed according to each specific case, taki: into account technical and economic factors. Domestic and industrial waste discharges are treated combined or separate. Separate water circuits withi: the plants are used when technology requires this solution to increase treatment efficiency. Important technical forces concentrate on water pollution prevention and control. This activity is coordinated by The National Water Council and carried out by local as well as its own authorities. The former are equipped with laboratories that enable them to verify and implement the measures planned, to collect and process the necessary information for co- ordinating and directing the general activities, as well as to provide state inspection and apply penalties when state discipline in the water field is infringed under the present legislation. If wastewater discharges cause damages to the national economy or endanger health, it is possible to order the plants that had caused the inconveniences to stop operation. The measures undertaken have not kept pace in all sectors with the in- dustrial and urban development of recent years. As a result on some water- courses, water quality did not meet the demands, difficulties being reportec 130 Ln the operation of certain users. Water pollution results in heavy damages for the national economy by requiring additional expenditure for water sup- ply treatment, by reducing or altogether stopping production in some plants, oy losses of useful substances discharged into wastewaters, by destroying fish, etc., damages evaulated to hundreds of millions a year. Alongside chese direct damages are the social effects, namely the impact on the public lealth, decrease of the economic and social development of polluted areas, 3estruction of aquatic fauna and flora, etc. Water resources being rather limited in our country, further develop- nent of production would very likely result in a deterioration of the pres- ent situation, leading to increased financial efforts and to difficulties Ln water use on more and more watercourses. For these reasons the program for the construction of treatment plant facilities assigns about 350 hundred million lei ($200 Million) for the period 1971-1975, which is more than double the investments made between L965-1970. The planning of pollution control works in our country is based on the. following principles: For new pollution sources the investments required by the indus- prial or urban objectives compulsorily include the wastewater treatment at :he very commissioning of the facility. For existing pollution sources, implementation of wastewater treat- nent plants or improvement of those inadequately equipped are to be made gradually, taking into account the importance and the state of the receiv- ing watercourses. Industrial and urban development is not to deteriorate riverwater juality beyond the limits required by water use and the self-purification )ossibilities , whereas for degraded watercourses a reduction of pollution las to be obtained. To establish the discharge conditions of wastewaters into river courses he general situation of the hydrographic basin is taken into account, pres- nt users as well as those required by the national long-term plan, present is well as future wastewater discharges, dilution and self-purification phe- nomena, the need to ensure at least a 3 rd river category, the minimum water 'juality on all watercourses. Such an analysis of a drainage basin results in the water quality man- agement plan, the tool which direct the whole activity of water quality jrotection in that basin. The water pollution control program implies an increased care in cor- relating the industrial techniques to water quality protection requirements Dy adopting new technological solutions for various industrial processes and an intensified reuse of wastewaters. Research in the field because of its complexity and its belonging to several departments requires the working out of a unique priority plan ■/hich would coordinate and direct the efforts to solve the problems, ac- cording to their economic and social importance. To this effect in March L971 a priority research program was developed for the period 1971-1980 concerning "Water resource protection and development." With regard to the water pollution prevention and control this program recommends: To determine the causes of water pollution and its effects on vater use and public health, as well as the tolerable pollution limits. To reduce the quantity and toxicity of industrial wastewaters oy in-process techniques. 131 To control pollutants in the natural environment by determining the self-purification and the artificially improving parameters of ground- water quality. To establish new wastewater treatment techniques (advanced physi- cal-chemical treatments, new highly-efficient coagulants extracted from in- dustrial wastes, new media for biofilters, etc.). To improve techniques in construction of wastewater treatment facilities. To process and remove concentrated wastewaters and the sludges resulted from wastewater treatment (improvement of digestion and dewatering methods and facilities, sludge and industrial wastes incineration, sludge and domestic refuse composting, etc.). To recover useful substances from industrial wastewaters and re- use of reclaimed water for land irrigation. In 1970 the "Air and water pollution control and personnel training program" was begun in collaboration with the United Nations Program for De- velopment through the agency of the World Health Organization. As far as water pollution control is concerned, the main provisions made in the project program are the following: Surface water quality protection (The Danube and the Arges river basin) and automated water quality monitoring. Soil and underground water pollution control, due to infiltration from sludge, garbage and industrial waste deposits. Working out of techniques, construction and facilities for muni- cipal wastewater and sludge treatment. The project provides also training of personnel by granting fellow- ships and technical advice by foreign consultants. To increase the efficiency of the measures to be taken new legislation is planned which will provide an adequate framework for the development of the water pollution control program. According to this legislation it will be strictly forbidden to put in- to operation new industrial plants or to extend others which would be water pollution sources because of their lacking wastewater treatment facilities or not meeting the requirements asked for by water management. Industries discharging wastewaters are obliged to reduce to the least possible quantity their effluent, to reduce its toxicity and reuse valuable substances. A study is in progress which will enable water management authorities to impose a tax on water use and discharge of wastewater into rivercourses or underground waters. Considering the complexity of the problems involved in water pollution prevention and control, the measures recently taken by our State are going to provide adequate background and promises to reduce further water pollu- tion by a constant effort of research, design, construction, operation and control, thus ensuring a rational use of water resources. 132 NEW PLANNING APPROACHES TO WATER POLLUTION CONTROL By Emanuel Blitz Head of Water Supply and Sewage Chair Civil Engineering Institute of Bucharest Water protection problems deriving from water requirement due to an in- reasing industrial development and better conditions for the growing popu- ation, involve a closer relationship between various compulsory operations. The most important of the existing protection works have been carried ut based on the collection and purification of effluents coming from local fewer systems. As compared to 1950, 1970 has brought about an increase of ' times the initial number of the local sewer systems. The number of the jreatment plants at municipal locations has also grown from 400 in 1960 to bout 1400 now. In view of the execution of these works, very large investments, stock nd man-power have been mobilized, while a wide operational program, meant o provide for its implementation by keeping up with the latest achievements f progress has been worked out. A comparison between various layout types of the last 20 years and the ost recent planning schemes reveal a quite different manner of approach to he standards of projects adopted. This rapid development had to be stead- ly backed up by means of legal measures and a suitable management framework esulting in substantial progress, even in the occurrence of temporary or artial slowdown, whenever technical or financial resources were unavailable. The process of planning waste systems regards them as determining ele- ents of local and industrial development, leading to efficient environmen- jal protection. Consequently they have to limit the operations within the ater management plan to have in view the perspective layout for urban and ndustrial systematization, to ensure protection to surface and groundwaters, n order to keep active means for further sanitation and new water applica- ions. The planning has closely followed up the requirements for the develop- ent of the country taking into account financial criteria, the economy, mailable materials, practical and mechanical data as well as facilities, echniques and performance. In the choice of the best scheme some of the following determining ele- ents have to be taken into account: separate or combined sewerage, allow- ing urban centers to join adjacent industrial units, possible linking to earby centers; available outlets for sewage discharge; phasing of works ut gradually into service — according to stage of execution; commissioning f facilities; and cost of water canalizing. A unique canalizing system integrating effluents as well as industrial astes (depending on their chemical contents) is offering good results, his approach may occasionally prove more profitable to treatment plants, ometimes however it may be related to the integral sewerage system or, ventually, to a given section of the network. The town of Pitesti located on the Arges River, a source of water sup- ly of the city of Bucharest, has its industrial wastes collected, after 133 partial treatment, in the main system of Bucharest, the achievement of better effluent standards resulting from simplified waste control tech- niques. The planning of a system in the Jiu Valley has required a great many variants. The best layout has brought into effect a sewerage net stretch- ing over a 35 km wide area all along the two branches of the river. The main treatment plant is receiving an inflow of 0.880 rn^/s by way of the sewerage network. The scheme, belonging to a microxonal layout, marks an important step into the fundamentals of sewerage problems having reference to our country. The first of these systems serves about 500,000 inhabitants of several seaside locations at the Black Sea and was carried out in 1955. Its grad- ual development turned into 3 large local systems. The collecting network of these stations surpasses 300 km while the discharge piping of the pump- ing stations reaches over 50 km. In practice we operate on the treatment of wastewater, that is on keep- ing in the treatment plant those matters which could be detrimental to nat- ural water quality. But in the actual technical conditions even wastewater treatment was not sufficient to protect certain valuable waterways. Hence the adopted solutions in such cases are different: some of them concern water quantities, others the means to ensure a certain purification degree, and at other times it is necessary to use outlets other than those to be expecially protected. The diminishing of the disposed water quantities constitutes one of the main approaches to river protection and as such facilitates the establish- ment of the methods of waste disposal. But the realization of this goal of reducing waste quantities, applica- ble to industrial wastewaters, involves on the one hand the use of some "dry" technological methods and on the other hand the adoption of some water recycling or reuse schemes. Thus the disposal of industrial wastewater is influenced by the inner water supply scheme adopted in the respective indus- try from the four possible groups of schemes: in open circuit , with reuse in steps (or in series) , with normal recycling respectively with joint cir- cuit or with intensive recycling in closed circuit (a scheme without waste disposal into an effluent sewer) . The means to ensure the necessary degree of purification are of criti- cal importance for the choice of the outlet and hence for the planning of the whole scheme. Until recently satisfactory treatment was "mechanical treatment," rea- lized most frequently by a small number of multistage cleaning tanks of Imhof f-Emscher type. An important improvement provides for biological treatment of wastewater which may involve one or several steps. The realization of such treatment plants is based on modern equipment designed and manufactured in this country, the range of equipment for me- chanical and biological treatment being relatively wide and — in any case — at an increasing development rate. There are nowadays currently designed nat- ural and artificial mechanical-biological plants such as: the biological treatment by irrigation fields at Palas-Constanta and Eforie-Sud, the waste- water treatment by biological ponds at Focsani, biological treatment by aer- ation tanks with activated sludge at Pitesti, Sibiu, Cimpina, Suceava, etc. For industrial wastewater, physical, chemical, physico-chemical and biological treatment — according to the circumstances — are used. In the near 134 future, the use of physico-chemical treatment as a clarifying stage for urban wastewater is foreseen. Changing points of effluent discharge to protect valuable waters is often needed. Thus wastewater from the new refinery of Pitesti is no longer discharged in the Arges River because its self-purification capacity was completely used up by the town wastewaters. As a result it was dis- posed into the Dimbovnic River, that flows also into the Arges River, but downstream of the water inlet for the water supply of Bucharest. The Black Sea shore is one of the beauties and riches of our country. The width of the beaches, their exposure to sun, the suitable fineness of the sand, the saltness of the water and its temperature during the summer constitute elements classifying the Black Sea coast among the most appre- ciated beaches in Europe. To maintain the cleanliness of this unique re- source, the wastewater is disposed of between April and October on the irrigation fields of Palas-Constanta and only during the period outside the bathing season is the wastewater disposed to sea after previous treat- ment. Special protection steps are taken for certain industrial wastewater discharges by homogertization and control basin arrangements. Thus in the case of the refinery of Pitesti where treated water is received into the Dimbovnic River through a pond with a 10-day holding period, sufficient respite to control and to take steps when water isn't adequately treated for disposal. The possibility to space at intervals the works under the conditions of putting into service the different parts as they are completed consti- tute a basic element in the actual concept of design. There are used for treating urban wastewaters gravity sedimentation tanks with mechanical cleaning, biological treatment by aeration tanks with activated sludge, the aeration being made by the classical method INKA and — in the last year — with aerators with a rotor designed and produced in this country; less used are biological filters that require frequently to pumping of the whole discharge of wastewater and give difficulties in oper- ation in cold regions and seasons. For the digestion of the sludge retained in the treatment plants, 10-15 years ago two-story tanks were used. Now, tanks for methane fermen- tation are used on a large scale with a modest beginning of aerobic stabi- lization of sludge. The economy of digestion tank design was much improved by passing from size determination on the basis of the served inhabitants to the dimensioning on the basis of the quantity of organic matters. De- vices for heating the sludge and stirring were improved too. The dewatering of the digested sludge from urban wastewaters is achieved on drying beds, a method that — in this country — is still most advantageous. Mechanized systems of rabbling and loading dewatered sludge were introduced. For industrial wastewater where the sludge quantities are large or the industrial process requires it, mechanical dewatering systems are used as: vacuum filters (in the pulp and paper industry) , pressure filters (in the coal industry, etc. ) . There is a trend to using existing basins for pretreatment of the in- flow along the sewerage network. For that purposes clarification plants with mechanically cleaning facilities have been employed, allowing the sludge to pass separately, either to the pumping station, or to independent 135 treatment facilities. New devices meant to increase the capacity of treatment plants or to improve existing facilities are built inside the treatment plants. At any rate, the decision to abandon an existing treatment unit has to be thor- oughly justified: one of the main reasons adopted in order to justify such a solution would be the needs for local extensions. The importance of these problems is steadily growing — more manurac- tured goods will gradually be produced and larger quantities of water will have to be treated. More careful attention is being devoted to the deter- mination of the main directions required to best meet the technical and economical requirements of our national economy and environmental protec- tion in our country. 136 INCREASED EFFICIENCY OF WATER TREATMENT BY FLOCCULANTS By T. Ionescu and S. Constantinescu Ministry of Agriculture, Food Industry, Forestry and Water Bucharest, Romania The practice of water supply for populated centers has proved that surface water clarification by flocculants is absolutely necessary, espe- cially in case of subsequent use of rapid filters. Flocculation is neces- sary also in certain types of wastewater treatment. Experiments proved that active silica as a flocculation — aid, increases the rate of reaction, enlarges dimensions and density of floes, and there- fore improves the sedimentation and clarification of treated water. Among the flocculation accelerators there have been recently used anionic and cationic polyelectrolytes , butyl or natural polyampholytes of polysaccaride type. The utilization of flocculants for water treatment is at present how- ever limited because the flocculants proper and the flocculating accelera- tors very expensive, having a great influence on the price of water treat- ment. The specific flocculating reagents are produced also in limited quantities and they are used only when strictly necessary. Starting from these considerations, first at the inorganic chemical technology department of the Polytechnic Institute Gh.Gheorghiu Dej, Bucharest, and then at the Food Research Institue, Bucharest — Baneasa, work has been done to produce flocculants with rapid and efficient clari- fication action, starting from raw material, accessible in rather unlimited quantities and having a very low price. Thus, a series of flocculants (T.I.) have been found, using as raw material natural and artificial sili- cates, metallurgical slags, used coal slags, fly ash from thermoelectric power stations, etc. The T.I. flocculants allow a practical application of the metallurgi- cal slags, fly ash and other useless industrial wastes. The T.I. flocculant preparation is based on the partial leaching re- action of the above-mentioned materials by means of diluted solutions of mineral acids; such acid solutions are obtained from aluminum, iron and manganese salts, etc., and from valicylic acid (partly in solution, partly colloidal), which acts as a flocculating accelerator. The above-mentioned metallurgical slags contain Si0 2 (3.4 - 60%), Fe 2 3 (13.7 - 45%), CaO (2 - 52%) , Al, MnO, etc. The T.I. flocculant preparation can be made under the same condition by replacing the mineral acid solutions by acid wastewaters from metal pickling facilities or by various industrial wastewaters with a mineral acid content. The content in active compounds of the T.I. flocculants, (a) from metallurgical slags at "Neferal" works, Bucharest, and (b) from fly ash at the termoelectr ic power plant of Craiova is 137 as follows: For (a) : R 2 3 — 22% Si0 2 — 27% For (b) : R 2 3 — 9.2% Si0 2 — 4% Owing to their composition (flocculant plus flocculating accelerator) , the T.I. flocculants produce extensive water colloid destabilizat ion. The principal conditions in which flocculation is produced and the characteristics of floes formed in surface water or wastewater treatments with T.I. flocculants are: (a) reaction time: 2 minutes. (b) floe dimensions: 1--3 mm. (c) floe sedimentations time: 15--35 minutes. (d) field of temperature for flocculation: natural temperature of water. (e) Turbidity after flocculation (slury content): (1) river water — max 2 — 3°, SiO? o (2) wastewater — max 10 , Si0 2 Results Obtained by Using the T.I. Flocculants After many experiments in treating water by means of T.I. flocculants, we can conclude that their action leads to the following performance: (a) Physical efficiency, consisting in turbidity decrease of sus- pensions in raw water: 90 — 99%. (b) Chemical efficiency, consisting in organic matter concentra- tion decrease from raw water: 80 — 95%. (c) Bactericidal efficiency, consisting in decrease of total bacterial number, including coliform: 75 — 95%. (d) Efficiency in removing organic micro-pollutants (mono hydroxyl phenols and synthetic anion-active detergents) : 50 — 75%. (e) Efficiency in radioactive water decontamination, consisting in removal of radioactive isotopes: over 94%. (f) Economical efficiency, consisting in reducing the cost of usual flocculating reagents: 1/4 — 1/5. The use of T.I. flocculants decreases considerably the investments for sedimentation units, as a result of detention time shortening by 50 — 70%, and for biological treatment plants, taking into account the physical, chem- ical, bactericidal and organic micro-pollutant removal efficiencies. Application of T.I. Flocculants According to studies and researches made in laboratory and pilot-plants, the T.I. flocculants have been introduced at the water supply of the Podari- Craiova sugar plants on Jiu River. The following projects have been made: wastewater treatment plant at Salonta slaughterhouse; wastewater treatment plant at IAS "30 Decembrie," Bucharest; the utilization of T.I. flocculants at the reef, pulp and paper combine, Chiscani (Braila) and at the procines complex, Caracal. At present, researches are being made for application of T.I. floccu- lants at many water treatment plants for urban water supplies. According to the circumstances, water treatment by T.I. flocculants 138 and lime solution can achieve other effects, as: (a) Reduction of temporary hardness of water before ion exchange treatment. (b) Decrease of certain negative phenomena produced by sapro- phytic micro-organisms. (c) Production of sludges with organic matter content, suitable for agricultural fertilizers. In case of slaughterhouse wastewater, the sludge attains a yield increase for tobacco, sugar-beet and tomatoes of 33 — 36%. In case of the sludge from porcine complex wastewater, the in- crease is approximately 30%. (d) Production of treated water to be used for irrigation or re- circulation for industrial processes. In some cases, wastewater treatment by T.I. flocculants need not be subsequent to biological treatment. In case of wastewaters containing great quantities of organic slurries, pre-treatment by a T.I. flocculant, followed by a biological treatment is recommended to decrease the BOD^ to accepted limits. 139 APPROACHES TO PREVENTION OF WATER POLLUTION By Mircea Negulescu, Lidia Vaicum, Vetena Ghederim Margareta Wlezek, Alexandru Cicei, and Angela Eminovici Deputy Director and Staff Members Research and Engineering Institute for Water Management Bucharest, Romania De-termination of Toxicity and Biodegradability of Some Pollutants Frequently Met in Wastewaters Owing to industrial development, especially of chemical and petrochem- ical industries which are producing various goods on a large scale, many organic chemical pollutants quite different from natural organic matter have appeared in industrial and municipal wastewaters. In many cases, these pollutants are biologically nondegradable or quite toxic for microorganisms in biological treatment plants or rivers, resulting in inhibition of the biochemical treatment or of self-purification in streams. Owing to their capability of metabolic self-regulation depending on conditions in the medium, microorganisms react against the occurrence of these pollutants by assimilation and detoxification processes. During these reactions, the cellule components can be modified, especially in the event that the final product has not become inoffensive for microorganisms. In the same processes, certain poisonous organic substances stimulate the admission of enzymes induced into cellules or can result in genetic mutations leading to adaptation of microorganisms either in the sense of survival in the presence of the poison or of a partial assimilation. In this latter case, the poisonous substance can be transformed into a biode- gradable substance. Starting from these considerations, our research concerning the cri- teria in determination of toxicity and biodegradability has been centered on the idea of detecting the modifications induced in the microorganisms of activated sludge. Toxicity Determinations The research was conducted using activated sludge obtained in contin- uous-flow laboratory units and being a model of industrial treatment plants, Some biochemical characteristics of activated sludge developed on easy as- similable subtrates have been determined as have the modifications produced by contact with pollutants having a more or less important toxic action. Studies have included the proteins, the glucides, the activities of some respiratory chains, enzymes and the cellular respiration, these being cor- related to some classical indicators of treatment efficiency, such as re- moval of COD and sludge index. The following conclusions have been drawn: The indicators investigated are constant for the sludge supplied under the same conditions (composition of nutritive substrate, air imput , organic load on the activated sludge) . 140 Short-period intoxication tests of activated sludge (made by acrylo-nitrile, methylene, violet, trichlorpropane) have demonstrated modi- fications of the studied, indicator values. Particularly sensitive have appeared proteins, microorganism respiration and dehydrasic activity. The least sensitive indicator for short-time intoxication intervals has been the COD treatment efficiency. From the quantitative point of view, modifi- cation of proteins has been the decrease of concentration; from the qualita- tive one — the change of proteic pattern obtained by sephades gel-filtration was followed by recording of transmission in ultraviolet of the esuated fractions. The oxygen uptake of microorganisms, and the dehydrasic activ- ity are lowered due to intoxication. By means of the indicators, one can follow the recuperation of activated sludge or the possibility of its acclimation to the given poison. The study of biochemical characteristics of sludge can lead to identi- fying the toxic traces in wastewater subject to biological treatment, before the effects of these poisonous substances are irreversible. Biodegradability Determinations In assessing biodegradability, three criteria have been used: Microorganism respiration, determined in Warburg apparatus and in the presence of testing substrate. Removal of this substance in the activated-sludge treatment plant, under standard operating conditions. Ecological characteristics of treated effluent, determined by its influence on aquatic organisms higher than bacteria as daphnies fish, etc. The degradation efficiency has been controlled either by substrate removal proper (when analytical means permit) or by percentage decrease of chemical oxygen demand. It has been stated that among parameters in respiration namely: Veloc- ity of respiration, hourly oxygen demand and concentration or organic matter in tested solution, there is an equation of type y= S— x, where: y represents the microorganism velocity of respiration in the presence of test solution compared to reference sample; x represents the ratio between oxygen uptake increment in % and COD, after allowing 24 hours to ascertain if a substance is more or less biodegradable. Moreover, between the respiration velocity of a standard activated sludge in the presence of pollutants and the treatment efficiency obtained in laboratory units there is a close relation which permits, by rapid respirometric determination, to estimate the removal of organic matter accomplished in the plant (COD %) . Respirometric methods have given very interesting results in determin- ing the biodegradability and toxicity of many synthetic substances such as chlorinated compounds, but there are some cases in which certain special physical properties of substances have not permitted -correlation between respirometric results and those obtained in activated-sludge units. One example is given by detergent biodegradability research for which respir- ometric methods did not yield adequate results, due to surface active properties of tested substances. The criteria for toxicity and biodegradability cannot be generalized. Besides biochemical and classical investigations to assess treatment effi- ciencies, specific criteria should be introduced dependent on circumstances. 141 Dewatering of Sewage Sludges The problem of sludge treatment has reached major importance within th«l general technology of sewage treatment. The treatment methods for sewage sludges are numerous. Dewatering has an important place. The natural de- watering processes (drying beds) tend to lesser applicability than mechan- ical processes (vacuum-f ilter , filter-press) , particularly for space saving and process-duration. The correct application of sludge dewatering processes is conditional on the knowledge of filtration characteristics of the material subject to treatment. These are the specific resistance to filtration and the coef- ficient of compressibility. In order to know the filtration characteristics of sewage sludge and to promote dewatering processes, it was necessary to elaborate a unitary methodology of determination and calculation, taking into account the existence of several variants. Among the known processes, the vacuum- filtrate volume measurement at different time intervals has been chosen. The effected researches have led to clearing up some aspects of the operating method and of the expression of f ilterability value. The deter- minations effected on different sludges of municipal and industrial sewage treatment plants in our country have permitted the following sludge classi- fication, according to the specific resistance criterion: Difficulty filterable sludges, having a specific resistance of 10 — 10 cm/g ; in this category one can include the raw and digested mu- nicipal sludges. Medium filterable sludges, having a specific resistance of 10 12 cm/g or less; in this category one can include some inorganic sludges and those resulting from feed water treatment. Easy filterable sludges, having a specific resistance of the lO^ cm/g; in this category one can include the sludges resulting from mechano- chemical treatment, fibrous sludges and conditioned sludges. In order to apply dewatering processes efficiently the difficultly fil- terable sludges must be previously conditioned for improving the specific resistance. Among the known conditioning processes, research has been made on thickening, elutriation, conditioning with inert materials and chemical conditioning . Previous research yields uncertain f ilterability improvement by sludge thickening. Our research revealed that thickening up to 8 — 10% solids con- tent improves the specific resistance of municipal digested sludges and also of some sludges resulting from mechano-chemical treatment. The elutriation of disgested sludge is recommended for sludges of spe- cific resistance over 1000. 10 10 cm/g. Research has shown the treatment op- portunity also for sludge of smaller specific resistance, since it leads to the decrease of coagulant consumption by about 40% and an efficiency in- crease of vacuum filters of 50%. Research has established a relationship for determing the elutriation ratio depending on the initial specific resistance, applicable for digested sludge under 1000. 10 10 cm/g specific resistance. The conditioning with inert material is taken into account in special cases (to improve the coefficient of compressibility) or combined with chemical conditioning to reduce the coagulant consumption. Our research recommends the use of thermo power plant slag combined with an efficient 142 material. Research concerning the chemical conditioning of raw and digested sludges led to certain recommendations of methodological character concern- ing the coagulant dose determination under laboratory conditions, on mix- ture, duration, intensity, and the determination of the technical limit in conditioning. The general equation of filtration with precipitate deposit on a porous medium and the knowledge of filtration characteristics of sewage sludges have helped to establish certain realationships which can be taken as basic for sludge dewatering plant dimensioning and for optimum operating condi- tions. Thus, equations have been established for determining the sludge dewatering duration in filter-press, the vaccum-f ilter efficiency and sludge dewatering duration on drying beds. Certain technical criteria in the choice of dewatering method have been established: 500 — 2000. 10 10 cm/g drying beds. 500 — 100. 10 10 cm/g vacuum filters. 500 — 50. 10 10 cm/g filter-presses. These criteria, which take into account economic considerations (dura- tion of dewatering, efficiency) offer the possibility that, depending on sludge characteristics, the proper dewatering method should be chosen. Quantitative and Qualitative Forecase of Municipal Effluent The preoccupation for experimental establishment of a specific pollu- tion index for municipal wastewater has been evidenced recently by continu- ous research activity in most countries. The great interest in tackling this problem must be explained by the need for realistic forecasting concerning the quantity and quality of waste- water discharged by different populated centers, i.e. the principal factors which dictate the size of treatment facilities and have a direct influence on costs. In forecasting the quality and quantity of municipal wastewater, we must foresee the future as a dynamic system with a complex structure. Industrial wastewaters vary in different localities leading to the use of analytical methods for forecasts concerning the quality of wastewater from populated centers. One difficult problem to be solved is that of the reliability of fore- casts. The solution of this problem cannot be obtained excepty by applying a probabilistic forecast model, which should permit expressing quantitively the degree of reliability. This way of touching on the problem creates the premise of a possible application of the modern prediction and decision theories belonging to the operational research and strategic games. In European countries, the values established by Imhoff a few decades ago are still utilized, despite opinions which contest their applicability. Although the notions of definition and the measurement methods used to de- termine the solids in municipal effluents shows a satisfactory homogeneity, the experiments have not lead to results certifying the homogeneity under experimental conditions. The main disturbing factors are related to the industrial wastewater and storm water. Although less generalized, the methods generated by the idea that measured magnitudes are statistical var- iables are more and more frequently used. This opens a large field of 143 application for mathematical statistical theories in organizing information and processing and interpretation of experimental results. The results als yield important modifications of the values established by Imhoff, especial the pollution index for suspended matter. The research has had the aim to furnish values of specific indexes to applied in the quantity and quality forecast process of the municipal efflu ent, these forecasts having a greater accomplishment probability and thus satisfying the exigencies with the confidence necessary for designing the treatment plants. The experimental basis has been a residential quarter whose population amounts to 15,700 inhabitants. The program of sampling was established before the beginning of the in vest igat ions. The experimental measurement volume was forecast depending o the main objective of the work, determination of the confidence interval of the average of each variable, measured at most with a departure * 10%, corr< sponding to a threshold of sensitivity = 0.05. The secondary objectives of the research have been to find the charac- teristic differences between the mean values of the variable which define the quantity and quality of wastewater depending on week days and daytimes, and also to find relationships betweeen these variables. The processing of analytical data has made evident the principal stati; tical parameters for each investigated variable. Their analysis has permit- ted the following: The forecast based on the necessary information volume proved to be true. The variable averages are characteristically differentiated de- pending on the laboratory treatment of the sample (raw settled water, fil- tered water) . The graphical and analytical tests have led to accepting the dis- tribution normality hypothesis for a great part of investigated variables. The departures from normality shown by certain variables (sus- pended matter and biochemical oxygen demand) can be attributed to certain displacements due to adoption within the sampling program of a certain sample type. The comparison of the values obtained by different experiments are converging into indicating important mutations in suspended matter structure and quantity produced per inhabitant, as compared with the Imhoff values. The experimental results are close to results obtained in experi- ments made in the F.R.G. and the Low Countries. The new values obtained for the decantable slurry led by their appli- cation in design to a more correct dimensioning of the facilities for sludge treatment, important savings being possible, estimated to be 10 — 15% of the total investment. It appears rational, from all standpoints, to utilize the new values of specific indexes after experimental substantiation and leadinc to a more adequate dimensioning of treatment facilities. Acquirement of Forage from Excess Activated Sludge Protein need in animal food is at present one of the great problems of the world, because of the important shortage in proteinated forages. In order to cover the necessities of proteinated forages, researchers from everywhere try to use the organic debris (mainly wastes from the food 144 ndustry) as such or as working material in acquiring forage yeast by means , f selected microorganism culture. Activated sludge, a heterogeneous culture of microorganisms with a high rganic matter — can represent also proteinated forage of high quality. One opes to resolve also the problem of removal of excess activated sludge, ctivated sludge represents a microorganism culture of very complex biochem- cal composition, among the principal constituents being: proteins, glucides, ipids, essential amino-acids, and vitamins. The principal problems in research into use of this proteinated forage re the following: Determination of sludge chemical composition and conditions which an improve this composition. Study of nutritive values and of acceptability by animals. The experiments have been initiated by means of activated sludge de- eloped in continuously fed laboratory units using sodium acetate. The biochemical analyses have indicated the following composition: 0-50% proteins, involving all essential aminoacids, 14-25% glucides, 7-13%' ipids, B2, Bg, PP, B-L2 vitamins, folic acid, pantothenic acid and nucleic .cids. In comparison with forage yeast, activated sludge contains more lipids, L and B-L2 vitamins, but less B2 and PP vitamins. Other activated sludges can have relatively modified compositions, de- fending on the substrate and on the operating parameters of the plant. Small rganic loads of activated sludge and large detention times in treatment lead o a decrease in protein percentage. Another problem has been the study of nutritive value and of activated ;ludge acceptability by chickens. For this purpose, sludge developed on ;odium acetate is used because, owing to laboratory conditions, the chemical imposition was constant and optimum with regard to protein concentration. Dry activated sludge, ground and sterilized by pasterurization, was :ubject to bacteriological control and then given as food in 5% ratio to a i-day chicken lot. The results have been positive. The chicken have accepted the sludge is a fodder showing a 10% weight increase against the reference lot. The above-mentioned data are our experiment results and they lead to :he conclusion that the excess activated sludge can be successfully used as >roteinated forage. The economical conditions of processing (drying, irinding, sterilization, etc.) are to be determined. 145 AIR POLLUTION CONTROL 146 AIR POLLUTION AND ITS CONTROL By Arthur C. Stern, Professor Department of Environmental Sciences and Engineering University of North Carolina Chapel Hill, N.C. U.S.A. There is not just one air pollution problem requiring control. Rather there are five separate categories of problems — Global, Continental, Na- tional, Urban and Local (Table I) — each quite different in scale and control requirements. Their common denominator is that all are caused by emission of gaseous and particulate contaminants into the air from sources; all are dependent upon the vagaries of wind and weather for the transport of contam- inants from sources to receptors; and, in all, there are one or more classes of receptors, human, animal, vegetable, material, structural, or the atmos- phere itself, that are adversely affected. Global Our global concern is that a change in the average chemical and physi- cal composition of the atmosphere may affect the temperature of the earth. The earth could be cooled, conceivably to the point of initiating another ice age, if atmospheric contaminants sufficiently reduce the amount of solar energy that can penetrate the earth's atmosphere. Conversely, the earth could be heated, conceivably to the point of melting presently existing po- lar ice, raising the sea level and inundating coastal cities, if these con- taminants sufficiently reduce the amount of the earth's heat that can escape from the earth into space as infra-red radiation. The contaminants whose build-up in the atmosphere could hypothetically cause reduction of penetra- tion of solar energy are suspended particulates, which have the ability to absorb and scatter solar energy, thereby preventing it from reaching the earth. The contaminants whose build-up in the atmosphere could hypotheti- cally cause reduction in infra-red radiation from the earth are gases such as carbon dioxide which have the ability to absorb infra-red energy and be heated in so doing. We know from measurement that the carbon dioxide and suspended partic- ulate matter content of the atmosphere has been increasing for the last sev- eral decades; and that the temperature of the earth has decreased slightly over the same time period. This may be interpreted as meaning that the op- posite effects hypothesized for CO2 and particulate matter increase may be counterbalancing each other, with the hypothetical effect of particulate matter to a slight extent prevailing. The implications these matters have with respect to air pollution con- trol are both unclear and disturbing. They imply that a major effort to decrease the particulate matter content of the atmosphere without a simul- taneous decrease in the C0 2 content of the air might tip a precarious bal- ance in one direction, and that the same could apply to any major effort at unilateral CO2 reduction without concurrent particulate matter reduction. 147 Since build-up of either particulate matter and gaseous contaminants alone is undesirable, it does not seem to be desirable to allow them both to build-up because we are unsure of what will happen if we disturb the bal- ance between them. Because the world's temperature is presently changing at such a slow rate, we are not now in a crisis situation where decisions have to be made and implemented rapidly. We have time to test the hypotheses from which the above noted implications ensue and, by improvement of theory and by ex- periment to refine our understanding of the effect of changes in atmospheric! composition on global ecology. We also have time to find out how to reduce • atmospheric carbon dioxide and particulate matter on a worldwide scale if it becomes imperative to do so. We certainly do not know how to do so now, either scientifically or politically. Scientifically, we are embedded in a technology that burns fossil fuel to carbon dioxide for energy and we see no clear path to a non-CC^ producing technology. Likewise, we are a long way from a technology that will restore the particulate matter level of the f atmosphere to that of a century or more ago. Finally, action to reduce the CC>2 and particulate level of the world's atmosphere must be a collaborative effort of all nations of the world; and as yet we do not have effective in- ternational political machinery to accomplish this. The only international organizations that we can look to for help with our global problem are the United Nations and its affiliated organizations; the World Meteorological Organization and the World Health Organization. The United Nations will have this problem on the agenda of its Conference on Problems of the Human Environment in Stockholm in June 1972. Background material on this subject is already in preparation. The World Meteorologi- | cal Organization has taken the initiative in coordinating a worldwide net- work of measuring stations which should give us better information as to long term trends of atmospheric carbon dioxide, suspended particulate matter and temperature. Continental The continental scale air pollution problem of greatest concern is the transport of pollution across international boundaries. The best documented example of this is the alleged transport of sulfur oxides from Great Britain and Germany to Scandanavia where it is apparently washed out of the air as "acid rain," resulting in decreased pH of water bodies and soil. An earlier example on a smaller scale was the Trail smelter in Canada, whose plume of sulfur oxides crossed the border to cause extensive crop damage in the United States. Transport on the scale postulated by the Scandanavian scientists studying the acid rain problem involves a large number of sources in one country combining to contaminate an extensive air mass which then moves to another country. This type of problem appears to be associated partcularly with the use of tall stacks to release untreated gases from the burning of sulfur-containing fuel or the smelting of sulfur-containing ore. The Cen- tral Electricity Generating Board of the United Kingdom has made a particu- lar effort to convince the people of the U.K. that its use of high stacks are alone a sufficient means of protecting them from high ground level sul- fur oxide concentrations in the vicinity of the stack. Questions are now being raised as to whether this use of high stacks, while safeguarding those 148 Lving in the U.K. , merely transfers the U.K. sulfur oxide problem to other iropean countries. For total control of sulfur oxide emission from large purees, tall stacks need to be supplemented by either the use of low sul- ar fuel or ore; the use of a system for removal of sulfur oxides from the Lue gases; or both. Low-sulfur fuel is transported from country to coun- ty as a highly prized item of international trade. Plants to reduce the jlfur content of both oil and coal prior to international shipment are coming more and more common. Likewise, the search for commercially racticable processes for sulfur oxide removal from flue gas is truly in- ernational. Among the nations having organizations known to be engaged in |=search and development of sulfur oxide removal processes are Czechoslo- akia, Federal Republic of Germany, France, Japan, Rumania, United Kingdom id United States. The matter of possible transport of sulfur oxides to Scandanavia from ther countries is on the agenda of the Organization for Economic Coopera- tion and Development, of which all the countries presently involved are Ambers. An international project to study the problem has been initiated, |ith the Norwegian Institute for Air Research as the lead agency. The transport of pollution across the Canada-United States interna- ional boundary has been under almost continuous study for the past several ecades by the International Joint Commission (U. S. -Canada) . Several such roblems have been brought under control; others maintained under interna- ional surveillance. ational On the national scale our concern is with what's happening to the air f places we normally consider unpolluted. We usually think of air pollu- ion as an urban problem from which we can escape by getting away from the ity into the clean air of the hinterland. Unfortunately, the air of the interland is becoming increasingly contaminated by urban air. The non- rban air masses moving into cities to flush tern is increasingly the dilu- ed air from the same or another city. The only control that can possibly educe non-urban background pollution concentration is the reduction of the rban pollution that causes it. There are also a class of pollution sources found only in non-urban reas. These include the burning of fields and agricultural wastes, crop praying, the tilling of soil, the disposal of animal excreta and of the astes from processing animal and vegetable products. As the world popu- ation increases, food and fibre production will increase. The only way we an prevent these kinds of pollutants from increasing in proportion is to hange the practices that cause them. It was noted that diluted urban pol- ution forms the background level of non-urban pollution. Where there are ppreciable non-urban sources, the converse situation occurs, i.e. the air dvected into urban areas is diluted non-urban pollution. At this point in our discussion, the distinction between primary and econdary pollutants becomes important. Primary pollutants are those emit- ed into the air from sources. Secondary pollutants are those produced in he atmosphere by chemical reaction among the primary pollutants. Many of he substances we call primary pollutants when emitted from man-made sources n urban areas, are emitted to the air from natural sources in non-urban reas. Where these primary pollutants react in an urban area, we call the 149 resultant secondary pollutants "smog." When these same kinds of substances react in a non-urban area we call the resultant secondary reaction products "haze." The necessary ingredients for the production of haze were present long before the present levels of urban pollution existed This is attested by the fact that all over the world there are mountains and forests that in antiquity were given names such as smoky or blue because of the natural haze so frequently observed above them. For both urban smogs and non-urban hazes to form, the primary reactants must be present in react able quantity and proportion for a long enough time and with a sufficiency of activating solar energy. There is a limited fre- quency of time during which the reactants emanating from an urban area meet these criteria; and, in a non-urban situation, during which those solely of non-urban origin do. The mixing of urban and non-urban air most likely has the effect of continously making-up reactant deficiencies, and therefore of increasing the frequency of time primary reactants will be present in reac- table quantity and proportion. With particular regard to the hydrocarbon- nitrogen oxide secondary reaction, one may hypothesize that mountain and forest air should be relatively rich in hydrocarbons and relatively defi- cient in nitrogen oxides; and that urban air should be relatively rich in nitrogen oxides but sometimes deficient in hydrocarbons. Any urban-non- urban air interchange that would enrich non-urban air with nitrogen oxides and urban air with hydrocarbons, would not only increase the frequency of occurrence of smog in cities and haze in the mountains, but also create con- ditions conducive to haze formation in the intervening hinterland We can- not prevent the evaporation of hydrocarbon vapors from trees and other vegetation, nor can we prevent urban-non-urban air exchange. The only things we can do in this situation is to decrease urban and non-urban man- made emissions. Urban The global, continental and national scales of the air pollution prob- lem heretofore discussed have been concerned mainly with the transport and diffusion of pollution produced in urban areas. However, the urban air pollution problem can be resolved only in the context of national and inter- national trade and commerce. Urban areas depend for their existence upon importation of fuel, energy, raw materials, food, water and manufactured goods, and on the export of goods, services and wastes. Restraints on quan- tity, quality and cost of any of these can affect the ability of an urban area to plan and carry out a long-term strategy to clean up its air pollu- tion. If each urban area were to plan and carry-out such a strategy inde- pendently, conflict would soon arise among their demands on national and world resources. Some measure of national and world planning and resource allocation is therefore required. Reduced to its simplest dimensions, a long-term strategy to reduce urban air pollution is the adoption and enforcement of limitations on emis- sions from each individual source within the urban area; the limitations being so chosen as to their time of application and severity as to achieve definite levels of air quality at definite future dates. During the time between now and that future date, the urban area must protect itself against the short-term occurrence of a level of pollution high enough to cause di- sease and death among its inhabitants. 150 Such short-term excursions are called "air pollution episodes" and can ccur when there is cessation of the normal wind movement that ventilates a ity for a period of several consecutive days. We call the simultaneous bsence of both horizontal wind movement and vertical convective air move- ent a "stagnation." Under conditions of stagnation, pollution concentra- ions build-up in the air over the city. The obvious tactical resolution f this situation is to rapidly and substantially decrease emissions for a eriod of several days until nature restores normal urban ventilation, uch tactical resolution requires some form of meteorological forecasting o warn in advance when a stagnation will occur and a well-developed sce- ario as to what steps the community will take once an episode emergency as been declared. l ocal The urban and larger scales of the air pollution problem are charac- ,erized by lack of ability to identify the specific source or sources of Ihe pollution received by any receptors. At these scales the receptor re- eives a mixture of pollution from so many sources that only by adding a nique tracer to the emission from a specific source can its transport to ihe receptor be demonstrated. The local scale of the air pollution problem s that for which the source or sources affecting a receptor can be identi- fied without the necessity of specifically adding a tracer. Abating the dentified source will abate its adverse effects on the receptor. Generally •here a single source or group of sources can be traced to one specific re- jeptor, it also can be traced to other receptors to which its effluent will >e transported under different wind conditions. The most common form of ocal problem is where the source of a unique odor can be identified Con- rol consists of reducing the odorous effluent to the point where it can no onger be smelled. Similarly, sources of unique particles or droplets 'ailing in a neighborhood can be identified and abated. It can be readily lemonstrated that street level carbon monoxide concentration is proportional :o traffic density along the street. Immediate abatement is to decrease ;raffic density; long term abatement is to decrease emissions from vehicles. lir Pollution Instrumentation An analysis of the market for air pollution instrumentation for 1970 :o 1980 was recently completed for the Air Pollution Control Office of the Invironmental Protection Agency of the U. S. Government. Although it de- fined only the American market, the levels and trends forecast have rele- r ance to levels and trends in other industrialized nations. The market is ihown to consist of three areas: instrumentation to measure air quality .evel, to measure emissions from stationary sources of air pollution, and ;o measure, emissions from automobiles. The principal findings are shown in ? igure 1 and Table II The conclusion is that most instruments pres- i ntly being made measure air quality, but that by the end of the decade tost instruments will be made to measure emissions from stationary sources Lnd automobiles. Concurrent with the above study of the instrument market, the research ind development needs for air pollution instrumentation were also studied foe findings of this study are summarized in Table III. The implications 151 of Table III are that unless and until the required new instruments are de- veloped and present instruments are improved, the market potential of Figure I and Table II will not be realized. Processes for Air Pollution Control The poorest method of air pollution control is to first produce a gas- eous effluent laden with contaminant vapors, mists or dusts and then apply a collection device to remove the contaminant from the gaseous effluent. The best method of control is to so design the process that it does not produce a contaminated effluent gas stream, i.e. to provide the desired product or service without the production of air pollution. There are numerous examples of alternate services and products that produce less pollution than those they replace. If the service is to heat a residence, and prior practice was to provide a fuel-fired furnace, stove or fireplace, the alternatives include heating by electricity, steam or hot water from a central plant. If the service is to provide transportation, and prior practice was to use individual motor vehicles, the alternatives include electrified vehicles on rails or railless; underground, or separate rights of way, or on streets and highways. An example of an alternate pro- duct is the substitution of a gas generated by gasifying solid or liquid fuel for the burning of that solid or liquid fuel. Other types of altera- tion that can be made to a process are changes in raw material, process chemistry, temperature, pressure and flow. Although a few processes are proprietary and can be obtained only from their developers, most processes are in the open literature and can be in- corporated into design by any competent engineering group. However, even when this can be done, it should be recognized that certain design and con- struction organizations are experienced with specific processes in which other organizations are novices. The experienced organizations have had the opportunity to learn from their mistakes and, presumably, will avoid them on the project in hand. The novice organization can expect its share of mistakes, but, unfortunately, these may occur on the project in hand. Air Pollution Control Equipment The term "Air Pollution Control Equipment" has come to mean dust col- lectors for removing particulate matter from an effluent gas stream; and scrubbers, adsorbers and afterburners for removing gases and vapors from an effluent stream. This is an unfortunate use of words because, as has been indicated, these devices are only a part of the resources available to the air pollution control engineer. In the United States, there is a trade as- sociation known as the Industrial Gas Cleaning Institute (IGCI) to which the bigger manufacturers of this kind of equipment belong. The greatest number of installations of simple devices such as settling chambers and cy- clone collectors are made by local tinsmiths, but the larger and more ex- pensive installations such as electrostatic precipitators, fabric collec- tors, and scrubbers are usually made by IGCI members, most of whom are licencees of European manufacturers, and who, in turn, have European licen- cees for their own proprietary designs. 152 Conclusion What stands out most significantly from even so brief a review as this, is that the air pollution problem is worldwide and that its solution will require a maximum of international collaboration and interchange of informa- tion and expertise. Certainly no one nation can by itself solve the global and continental aspects of the problem. Even when the scale of the problem diminishes to compatibility with the political boundaries and jurisdiction of one nation, we find that the search for the necessary control technology transcends such boundaries. One can comprehend the motivation of individ- ual nations each to duplicate the efforts of others in matters of national security. However, where the security of the world's atmosphere is at stake, the scarce supply of professional air pollution control talent, re- search and production resources should be shared on a worldwide basis. NOTE: Portions of this paper have been incorporated in the paper, "Air Pollution — A Worldwide Problem Requiring Worldwide Solution," the author is presenting at the Session on Air Pollution Control of the Technical Meeting, Pro Aqua-Pro Vita 71, (Noise Control — Air Pollution Control — Water Economy), June 9, 1971, Swiss Industries Fair Halls, Basle, Switzerland. REFERENCES 1. R.R. Bertrand, The Market for Air Pollution Instrumentation 1970-1980 Journal of the Air Pollution Control Association, Vol. 20, No. 12 pp 801-3 (December 1970) . 2. R.R. Bertrand, A Study of the Market for Air Pollution Instrumentation 1970-1980 under Contract No. CPA 22-69-154 for the Air Pollution Control Office, February 1971, Table 6. 3. H.J. Hall, N.L. Morrow and R.S. Kirk, Research and Development Needs for Air Pollution Instrumentation, Journal of the Air Pollution Control Association, Vol. 20, No. 12, pp 804-7 (December 1970) GENERAL REFERENCES Air Pollution Technical Information Center (APTIC) Office of Technical Information and Publications (OTIP) Air Pollution Control Office Environmental Protection Agency, P.O. Box 12055 Research Triangle Park, North Carolina 27709, USA This office has published approximately 90 paperbound publications in its AP series; approximately 68 paperbound publications in its APTD series; and others in its PB and FS series. A few of these are also available in hard cover editions. Lists of these publications and their availability may be obtained by writing to APTIC. APTIC also publishes "Air Pollution Abstracts," which abstracts the world's air pollution literature. 153 Air Pollution Control Association 4400 Fifth Avenue Pittsburgh, Pennsylvania 15213, USA This association publishes a monthly journal and other publications relevant to air pollution. From 1955 to 1971, it published "APCA Abstracts," which abstracted the world's air pollution literature. American Industrial Hygiene Association 25711 Southfield Road Southfield, Michigan 48075, USA This association publishes a monthly journal and other publications relevant to air pollution. American Public Health Association 1740 Broadway New York, New York 10019, USA This association publishes "Health Laboratory Science," in which journal are published the Standard Methods of Ambient Air Sampling and Analysis of the Intersociety Committee of eight American pro- fessional societies. Academic Press, Inc. Ill Fifth Avenue New York, New York 10003, USA This company publishes "Air Pollution" (Edited by Arthur C. Stern) 2nd Edition — 3 Volumes (1968) which is the most complete air pollu- tion reference and text book published in the United States. 154 TABLE I Categories of the Air Pollution Problems Category- Vertical Scale Temporal Scale Global Continental National Urban Local The Atmosphere The Stratosphere The Troposphere The Lowest Mile The Height of Stacks Decades Years Months Days Hours 155 TABLE II Estimate of Air Pollution Instrumentation Market Total Value 1970-1980 (2) Millions of Dollars Initial Market Purchase Replacement Total Ambient level Agencies* Continuous Air Monitors Agencies* (Non-automatic Devices) Stationary Source Emissions Industry Agencies* Auto Emissions Agencies Service Area Industrial (Assembly line testing) 25 17 42 10 6 16 168 46 214 12 5 17 47 19 66 88 18 106 2 1 3 ♦Agencies = Air Pollution Control Agencies Total 464 156 TABLE III (3) Research and Development Needs for Air Pollution Instrumentation A. Instruments Exist But Need Improvement or Modification 1. Stationary Source Emission Measurement (a) Portable Isokinetic Samplers (b) Simple Flow Detectors (c) Emission Factor Determination 2. Mobile Source Emission Measurement (a) Certification Testing (Particulates) (b) Simple Package for Service Stations (c) Real Time Analysis of Hydrocarbon Type (d) Odor Measurements 3 . Ambient Air Quality Measurement (a) Sensitivity of Integrating Instruments (b) Selectivity of Instantaneous Instruments (c) Global Pollutant Mapping (d) Particulate Mass (Instantaneous) B. Need Exists But Instruments Do Not 1. Stationary Source Emission Measurement (a) Analysis at Stack Conditions (b) Particulate Average Across Stack (c) Integrating Flow Detectors (d) Referee Methods for Emission Factor Determination 2. Mobile Source Emission Measurement (a) Standard System for Inspection Testing (b) Portable Package for Spot Compliance 3. Ambient Air Quality Measurement (a) Simple Cumulative Collectors (b) Long Path Analyzers (c) Multicomponent Gas Analyzers (Instantaneous) 157 1 1 1 1 \ o»- \ CO ^ \ CO LU \ ^ UJ \ uj a: \ y^ SOURCE ^ MEASU ^r _i r LU > UJ _J I— UJ CD UJ UJ (X, ID CO 1 < # UJ # ■2. O CO CO LU AUTO EMI UJ QC Z> CO < UJ 1 1 1 o CO CO < UJ o in o ■p x u at a c o -p ■P C | 9 u ■p w c P. o u fa e •H P. en •H 1*4 ^ CO CVJ i-H dV3A d3d suvnoa Nomiw 158 ESTABLISHING THE EXTENT OF AIR POLLUTION CONTROL REQUIRED By Arie Jan Haagen-Smit Division of Biology- California Institute of Technology- Pasadena, California USA Air pollution, one of the trademarks of our technological culture, is the result of several factors acting in concert. Emissions from natural and man-made sources provide the polluting substances. Meteorological fac- tors such as wind and temperature inversion, together with topography pre- scribe the dilution volume that is available for the dispersal of these substances. In certain instances, the sun plays a part in the formation - of an air pollution problem by providing the requisite energy to convert innocuous substances to materials that can damage vegetation, irritate the senses, impair visibility, and affect the health of humans and animals. The natural forces, man can do very little to modify; he can only prevent or reduce emissions resulting from his own activities. If polluting activities could be eliminated, there would not be the air pollution problem that is being experienced worldwide. Unfortunately, many of these activities must be retained because they are essential to our comfort and well-being. There is a delicate balance between our preference to retain these activities, and our desire to protect the air environment. An essential step in maintaining this balance is a careful determination of the extent of air pollution control that is required. Air Quality Goals The first step in determining the extent of air pollution control re- quired is the setting of air quality goals, which are usually stated as a series of ambient air quality standards. In California, such a standard is defined as "a specific concentration and duration of an air pollutant which reflects the relationship between the intensity and composition of pollution to undesirable effects." Recently, the United States federal government, in recognition of the differences in effects, has separated air quality standards for each air pollutant into two classes: primary and secondary standards. A primary air quality standard specifies the concen- tration and duration of an air pollutant which should not be exceeded as a "requisite to protect the public health," including allowance for an ade- quate margin of safety. A secondary ambient air quality standard should not be exceeded as a "requisite to protect the public 1 welfare . " In this sense, public welfare includes "but is not limited to, effects on soils, water, crops, vegetation, man made materials, animals, wildlife, weather, visibility, and climate, damage to and deterioration of property, and hazards to transportation, as well as effects on economic values and on personal comfort and well-being." Air quality standards, in order to be most useful in the control of air pollution, must be based on scientific information that describes 159 conditions of exposures versus effects. The standards must not be arbi- trarily established, although a safety margin may be prescribed when the basic data are incomplete or when there are uncertainties regarding the scientific findings. In practice, however, air quality standards have not always been established so ideally. In 1959, when ambient air quality standards were first considered by California, the Health Department, and its scientific advisors discussed in depth the theory and bases for such standards The factors that were considered pertinent in setting standards were summarized in a technical report (*■> . These important considerations are briefly summarized as fol- lows : Let us consider a standard based on effects of human health. The re- sponses of a single homogeneous population would be as represented by the response curve in Figure 1. The value Xt is the threshold or minimum con- centration at which any individual in the population will feel an ill effect. The standard should be set at no higher concentration than this level. If we were to define two separate homogeneous populations, one being more resistant than the other, our response curves would be as in Figure 2 with two separate threshold concentrations, X^^ and X.)-^. However, when the two groups are combined and not distinguishable, the lower value, X t ^^ is the threshold. In a complex population of an entire community, consisting of people with a wide range of susceptibility, the response threshold falls lower and lower as more people are observed. Even at extremely low levels there may be hypersensitive people who will feel an ill effect. The response curve of such a population would appear as in Figure 3. The threshold would be low and difficult to specify With some pollutants there may be no concentration level that affects absolutely no one. Therefore, in the real situation, zero effects do not appear to be a good basis for setting an ambient air quality standard. One approach that could be used would be to select a concentration level as a maximum which would have no effect on a large portion of the population, say 99 percent. Such a standard based on this concentration would protect 99 percent of the population. Protection of the remaining 1 percent would be an individual responsibility involving medical care through the individuals' physicians. Let us now consider "cost" in its broad concept in setting ambient air quality standards. Air pollution is costly in terms of damages to materials of discomfort, ill-health or inconvenience. While damages to materials can be assessed in monetary terms, it is difficult to do likewise for the other effects. However, there will be a "cost," and the sum of these costs in- creases with the concentration of the pollutant. The control of air pollution is also costly, and the cost of control generally increases with the amount of control or prevention needed. It would be logical to choose a control program where the total cost is a min- imum. In Figure 4, the costs of air pollution, and control are plotted against pollutant concentration. The additive curve which shows the net cost, indicates that there is a pollutant concentration where the net cost is a minimum. Another aspect of air pollution that should be considered in setting ambient air quality standards is that a single pollutant may have many 160 =parate effects. Figure 5 shows the complexity of the effects of such a ollutant, sulfur dioxide. Some pollutants at concentrations generally found in the atmosphere, 3 not cause undesirable effects directly. Such pollutants may react in tie air to form substances that irritate the senses, damage vegetation and aterials. Hydrocarbons and oxides of nitrogen, for examples, participate n photochemical reactions that lead to smog manifestations of which eye rritation is one. Laboratory studies, however, indicate that the rela- ionship between eye irritation and irradiated mixtures of hydrocarbons and sides of nitrogen is not one which can be simply and clearly defined, igure 6 is a graphical representation of laboratory data showing the ob- ferved eye irritation intensities versus hydrocarbon and oxides of nitrogen (Dncentrations. The eye irritation severity zones are separated by iso- jesponse lines which represent the times in seconds it took the test subject p notice eye irritation after being exposed to the irradiated mixtures. he data show that a given level of eye irritation is not attributable to last one particular mixture, but that different mixtures may produce eye rritation of equal intensity. The complex relationships between pollutant concentration and effects iake selecting a basis for ambient air quality standards difficult. Diffi- ulties notwithstanding, standards must be considered for all pollutants aving either direct or indirect undesirable effects. l ata on Air Quality The next step in establishing the extent of air pollution control re- uired might be to determine the existing ambient concentrations of the arious pollutants for which air quality standards have been set. For this, ollutant concentrations need to be measured. The information obtained is sed to determine how much it will be necessary to reduce the pollutant evels, and in turn how much emission control is needed, to reach the air uality standards. Adequate air monitoring is also costly. Each set of instruments that easures just the principal pollutants may represent an investment of thou- ands of dollars. This does not include the technical staff that is required o operate, maintain and calibrate the instruments. Because the concentra- ions measured are in the order of a few parts per million for some pollu- ants and a few parts per hundred million for others, the accuracy and re- iability of the instruments are particularly important. For the pollutants that must be monitored by spot sampling, there is he drawback that samples must be analyzed in the laboratory. Hence, the nalytical results are not immediately available. These measurement pro- edures are for a long period; they yield no knowledge of how the concen- rations in the atmosphere varied during the sample period. With particu- ate matter there is the additional factor of particle size, which is losely related to possible adverse health effects. Most of the measure- ent procedures currently used are based on total sample mass and gives no ndication of particle sizes. The large investment, both in terms of capital outlay and manpower, equired to maintain a continuous monitoring station limits the number of ocations where measurements of pollutant can be made. In order to fulfill heir objective, the few stations must each be placed in strategic locations, nd must produce data which represent exposure condtions prescribed in the 161 standards . Sources of Air Pollutant Emissions We have set ambient air quality standards, measured the actual pollu- tant concentrations in the air, and we know something about how much control will be required. Now, we need to determine the sources of pollutant emis- sions, which of these should be controlled, what control technology can be applied to specific types of source and to what extent. The type of information obtained in such surveys is shown in Figure 7. These data are for the South Coast Air Basin in California, which includes the large metropolitan region in the Los Angeles area. This basin covers about 8600 square miles and has a population of about 9.8 million. If resources technology and authority for control were unlimited, air quality prescribed in the ambient air quality standards could be achieved quickly. But of course this is not the case. Therefore, it is necessary to establish control priorities, considering the largest source of the major pollutant, and those for which control technology is available and can be applied. The source inventory such as shown in Figure 7 can provide a guide for determining of such priorities. This area, indeed all of California, uses very little coal. Therefore, the area is relatively free of sulfur dioxide and particulate matter emis- sions which are typical of a coal burning area and constitute the major air pollution problems of such an area. On the other hand, the frequent periods of low wind speeds and of atmospheric temperature inversions produce per- sistant atmospheric stagnation. These conditions coupled with a high inci- dence of solar radiation are ideal for atmospheric photochemical reactions. Consequently, the most serious air pollution problem is a photochemical one, produced by the action of sunlight on hydrocarbons and nitrogen oixides in the area. High oxidant concentration is one of the manifestations of photo- chemical air pollution, and this area experiences regularly the highest oxidant concentrations known. Referring again to Figure 7, we note that motor vehicles are the major source of both hydrocarbons and nitrogen oxides. Therefore, to reduce oxi- dant levels in the South Coast Basin we must control emissions from motor vehicles. The next largest source of hydrocarbons is organic solvent usage. The next largest source of nitrogen oxides is fossil fuel power plants. If a high degree of control is needed to reach the adopted air quality stand- ards, controlling motor vehicle emission alone is not enough. We must also consider controlling these other sources. Another problem in the South Coast Basin is carbon monoxide. As Fig- ure 7 shows, motor vehicles are almost the sole source of this pollutant. Methods for Determination of the Necessary Reduction in Emissions The simplest method of determining the degree of control needed is through "rollback" calculations. For example, consider sulfur dioxide. The basic equation for this calculation is c j 8 x 100 = percent reduction required, where c is the maximum measured concentration, and s is the air quality standard. The ambient air quality standard (s) for sulfur dioxide in California is 0.04 parts per million, 24 hour average. The maximum at- mospheric (24 hour average) concentration (c) recorded by air monitoring 162 in the South Coast Basin was p. 14 parts per million, Therefore, to avoid exceeding the standard, we need to reduce the atmospheric concentration by 0. 10 parts per million, or by 70 percent. To do this we must reduce sulfur jdioxide emissions from all sources by the same percentage. This method can also be used for estimating control needed of pollu- tants that cause smog effects indirectly. In Figure 6, where the resulting ieye irritation intensities are shown against various starting mixtures of jhydrocarbon and oxides of nitrogen, the areas close to either axis are in ;the no-or-slight-eye irritation zone. To eliminate eye irritation, the two pollutants must be controlled to levels within this zone. To estimate the degree of control needed for either or both of these pollutants, it is essential to know their pre-reaction concentrations on smog days and on non-smog days. In Los Angeles, typical morning concentra- tions for the days thusly categorized are represented by the two elliptical I areas shown in Figure 8. The dotted line through these two areas approxi- mates the ratio of the two pollutants as determined from emission estimates. The laboratory data represented in Figure 6 and the air monitoring and ;emission data shown in Figure 8 could be combined into one figure for the purpose of determining the required degree of control. This is shown in ; Figure 9, which indicates that about a 70 percent reduction of both pollu- tants is required to go from "smog days" to "non-smog days." As the approach is based on the maximum concentration, the calculated degree of control will be more than adequate for less polluted areas. '"Rollback," however, has several drawbacks. First, each monitoring station records the pollutant concentration at its location. There is no assurance > that the true maximum concentration is being recorded at any station, re- igardless of how many stations there are. Second, by this procedure we are (requiring a degree of control that is more than adequate over large portions of the Basin. This may be wasteful of the resources for control which might be better spent on controlling some other pollutant. Third, we may not be able to reduce emissions from some sources by 70 percent because they are already being controlled to near the maximum degree possible. Another method for estimating control requirement is to consider that the air over the basin has a certain dilution capacity which is limited by the height of atmospheric temperature inversion and the boundaries of the basin. This approach is the "box model" (2) ( illustrated in Figure 10. The air over the basin is considered as a box of volume V. The height is h, the height of the inversion; the wind is assumed to be of constant speed v and direction. The box is oriented with one face of length L-- perpendicular to the wind; the source emission rate within the box is S mass per unit time, assumed constant. The following are also assumed: (1) instantaneous perfect mixing within the box, so that pollutant concen- tration C mass per unit volume is uniform in the box at any time, (2) uni- form and constant air pressure and temperature throughout the box, (3) reactions involving the pollutants are ignored, and (4) the wind blows only clean air into the bos at the rate of Q = hLv, and dirty air of concentra- tion C leaves the box at the same rate Q. The differential equation of the model and its solution are as shown in Figure 10. This model provides estimates of concentrations of pollutants that are emitted throughout an area at a known rate. The reliability of the esti- mates depend on the closeness the situation is to the assumptions listed. In actuality, mixing within the box is far from instantaneous and perfect; the air pressure and temperature and wind velocity and direction are 163 not uniform throughout; and finally, most pollutants are not inert, others are produced from reactions in the atmosphere. A serious deficiency in this approach is that it provides an average concentration and misses the high values which a control program should be designed to prevent. Rather than combining the emissions from all sources and uniformly dis- persing them over the basin, a more sophisticated method would be to treat individually the effect of each source on the air quality in a given loca- tion, and sum these effects into one total. The dispersion of a plume from a point source over an area has been described by nonlinear partial differ- ential equations^'. An approximate solution to these equations is known as the Gaussian dispersion model: . r( * -2. (_ I (h - z) 2 H C(x,y,z) = ffucJ a exp( 2 2 z y I a z I where C is the calculated concentration at the point x,y,z (g/m3) Q is the point source emission rate (g/sec) u is the wind speed (m/sec) o z , o y are the vertical and horizontal diffusion parameters (m) x is the distance from the source in the downwind direction (m) y is the crosswind distance from average centerline (m) z is the height of the receptor above ground (m) h is the effective source height above ground (m) For application under certain assumed conditions, including ground level (z = o) and at the plume center line (y = o) . The dispersion model is simplified to 20 f C(x,y,o) = exp' 2 x ud 2* z 16 The equations can be further refined by evaluating the constants, in- troducing the limiting parameter of the inversion height and assuming it equal to the mixing depth, applying factors to account for the relative frequencies of various wind speed, and introducing parameters to account for atmospheric stability conditions. However, when the model was applied to an actual case, the relationship between the measured and calculated concentrations was not conclusively established. This may be due to inade- quate meteorological data, variations in elevation of the terrain, roughness of the terrain, inaccuracies in the model and the transport of pollutant into the area from outside. Even with these difficulties solved, this model might suffice only for isolate point sources. It lacks provisions for considering the interactions of the numerous sources in a large area, and the effects of the photochemi- cal reactions. If the model can be verified against actual air monitoring data, it can be a powerful tool in advanced planning to locate future resi- dential, urban, or industrial expansions. Conversely, the model can indi- cate the necessity of removing existing installations from their present locations. 164 :ontrol Options Options that are available for control also have an important bearing n deciding the extent of control. These options are selected according to he type of sources, the kinds and quantities of emissions from these sources, leasibility of control, alternatives, and sometimes public pressure. Some >ptions are exercised without first quantifying the benefits of the options, jithers are aimed at achieving a calculated reduction in emissions. Within :he spectrum of options, there are: a complete ban on emissions, equipro- >ortional control, selective source control, and prevention of new sources. A complete ban on certain activities can be enforced in some cases /here there are suitable alternatives to the practice being banned. Open turning and waste disposal in inefficient incinerators, for examples, have >een banned in many places. Such a ban requires that the material which had seen burned be collected and disposed in another way. Equiproportional control is practically suitable for a number of closely ;imilar individual emitters. Having estimated the degree of reduction on :he average, the degree of control if imposed on all similar sources. An example of this is the control of emissions from gasoline-powered motor ve- licles, where every unit in an applicable model year is required to comply /ith a given set of emission standards. Selective source control is practiced in cases having a number of di- verse source types. Selective control may be taken according to area, sason and atmospheric conditions. Sources in areas where the problem is severe may be more stringently controlled than those in other areas. Regu- .ations may be established for a specific season or for uncertain meteoro- .ogical conditions. In this option, a high degree of judgment is required, )ut it provides the greatest opportunity for minimizing costs to society. Honsideration must be given to a number of factors, which include: (1) Source types — major, or of secondary importance; individual sources are large or small. (2) Source locations — sources are isolated and have small envi- ronmental effect, or are located so as to have a relatively large effect. (3) Possible seasonal source characteristics. (4) Practical and technical feasibilities of optional control methods . (5) Ease of imposing controls. (6) Public acceptance of controls. The control of photochemical air pollution in California is an example 3f selective source control. Photochemical air pollution, the main problem Ln metropolitan California, results from reactions involving hydrocarbons and nitrogen oxides. By far the major source of pollutants is the motor /ehicle. Therefore, to reduce the effects of photochemical air pollution, :ontrol vehicle emissions must be curtailed. For hydrocarbons, the next Largest source after motor vehicles is organic solvent usage, such as in surface coating and degreasing operations. It is practically and techni- :ally feasible to replace some highly reactive hydrocarbons in solvents tfith those having low reactivity in photochemical reactions. It is also *asy to impose such controls, and hence regulations on solvent usage re- flect this approach. The combustion of fossil fuel for heat and power account for about 165 half of the nitrogen oxides emissions from stationary sources. Here we have a choice between controlling a few large power plants and hundreds of thousands of home space and water heaters, and small commercial boilers. Again, because it is easier to control large power plants, stringent emis- sion requirements are imposed on these sources. Small domestic sources, although collectively accounting for a sizable quantity of oxides of nitro- gen emissions, are not controlled. Prevention of new sources is the last control option. This option could be used in heavily polluted areas that cannot tolerate any addi- tional sources. In the future, prevention of new sources may include changes in transportation system, population limitations and other measures that will limit additional polluting activities from entering an area in which the diluting capacity of the atmosphere is already exceeded. Power generating plants can be located away from metropolitan areas. Fossil fuel plants can be replaced by nuclear reactors. Implementation of Controls Control requirements, however sensibly and firmly established, produce no benefits until they are implemented. Air pollution problems cannot be mitigated by enacting a law, or by adopting rules and regulations alone. Regardless of the pressure of demand, emission reduction cannot be realized if the control technology does not exist. Even when technology is available and can be readily applied, a continuing adjustment of the program is neces- sary to assure that the controls are effective and adequate. Figure 11 illustrates the fact that emission control envisioned today will not be adequate in future years. Control requirements must undergo continuous assessment, and must be tightened as new technology is developed. The figure shows the estimated nitrogen oxide emissions in the California South Coast Basin from 1940 to 1990 based on the present control program. By 1990, the miscellaneous small sources will have increased to account for more than half of the total emissions. Power plant emissions will remain about the same, although there are good possibilities that they can be de- creased by control measures currently being investigated and by replacement of fossil fuel plants with nuclear ones. Motor vehicle emissions decrease markedly until about 1985, and thereafter decrease further by another small increment until 1990. After this time, despite the fact that emissions from individual vehicles will have been reduced by over 90 percent, total vehicular emissions will again increase due to the increase in the vehicle population which has steadily gone on year after year. Summary The factors that must be considered in the establishment of control re- quirements are numerous and complex. These include goals for air quality, the sources of air pollutants, control options, program implementation, and plans for the future. A control official does all this with the certain knowledge that his decisions, regardless of how carefully made, involve some uncertainties and a possibility of his objectives not being accomplished. It should be obvious by now that the role of an air pollution control official is unending and difficult. Too often he is accused, perhaps in the same breath by the same people, both for being too lenient and therefore 166 ineffective and neglectful of the public welfare, and for being too strict in requiring unnecessary controls therefore inconsiderate of the public welfare. His principal mission is one of protecting the health and welfare of the community as a whole. In his earnest effort to achieve his objec- tive, he may succeed in pleasing very few people. REFERENCES 1. California State Department of Public Health, "Technical Report of California Standards for Ambient Air Quality and Motor Vehicle Exhaust," 1959. 2. Stanford University — Ames Research Center, "Air Improvement Recommenda- tions for the San Francisco Bay Area," October 1970, prepared under NASA Contract NGR-05-020-409. SUGGESTED AIR POLLUTION REFERENCES Meteorology — Helmut Landsberg , Ph.D., "Physical Climatology," Gray Printing Co., Inc., DuBois, Pa., USA. Air Pollution — Arthur C. Stern, editor, "Air Pollution," 2 ed. , 3 volumes, Academic Press, New York and London (1968) . Air Pollution — Periodicals a. Atmospheric Environment--Pergamon Press, England. b. Air Pollution Control Association Journal, 4400 Fifth Avenue, Pittsburgh, Pa. 15213, USA. c. Air/Water Pollution Report, Business Publishers, Inc., Silver Spring, Maryland 20910, USA. Diffusion Models — "Proceedings of Symposium on Multiple-Source Urban Diffu- sion Models," U.S. Environmental Protection Agency, Air Pollution Control Office, Research Triangle Park, North Carolina, USA. 167 POPULATION RESPONSE VS. POLLUTION CONCENTRATION (One homogeneous group) CONCENTRATION OF POLLUTANT Figure 1 POPULATION RESPONSE VS. POLLUTION CONCENTRATION (Two separate homogeneous groups) CONCENTRATION OF POLLUTANT Figure 2 COST VS. POLLUTION CONCENTRATION POPULATION RESPONSE VS. POLLUTION CONCENTRATION (Complex population) CONCENTRATION OF POLLUTANT CONCENTRATION OF POLLUTANT Figure 3 Figure 4 168 u POPULATION RESPONSE TO VARIOUS EFFECTS OF SULFUR DIOXIDE CONCENTRATION OF SULFUR DIOXIDE Figure 5 OBSERVED EYE IRRITATION AT DIFFERENT OXIDES OF NITROGEN AND HYDROCARBON CONCENTRATIONS (Laboratory Fumigation Data) Hydrocarbons — ppm Figure 6 169 Percentage of Emissions From Major Sources in South Coast Basin 1968 Notor Vehicles Motor Vehicles NITROGEN OXIDES 1370 TPD HYDROCARBONS 3500 TPD Others k'^ Petroleum Others Power Plants Others 3^ Organic Solvents CARBON MONOXIDE 13500 TPD Motor Vehicles Motor Vehicles Minerals & Chemicals PARTICULATES* 200 TPD Others Minerals & Chemicals Power Plants and Other Fuel Combustion SULFUR DIOXIDE 380 TPD Motor Vehicles Petroleum Power Plants * Photochemical Aerosols not Included TPD = Tons Per Day- Figure 7 170 o < z CD s o o en •H fa uidd — sapixQ ua6oj>!fj UI O O (A O — i oc UI H > ^ UI Z -1 u. O 0) z o > < Q Ui < O (J o « z 5 o ° HI o * 5 » s ss< 2 OC a H < o < o s O OC " UI O > > oc z UI (0 Q CD Z o < \ ill \ \ \ e -" E a a I 00 0) u •H fa iudd — sapixo u»6ojjin 171 FIGURE 10 BOX MODEL Q = hLv L = length of face perpendicular to wind h = height of inversion v = wind speed Q = volumetric rate of air movement S = source emission rate Let Ct = concentration in box at time t C = concentration in box at time t = o T = V/Q, average residence time of pollutant Then by mass balance, we have or The solution is y dc - s - QC dt dc = S - C dt V T C (t) = S (1 - e" t/T ) + C e _t/T Q As t» T, C (t) S/Q 172 Estimates of Oxides of Nitrogen Emissions in The South Coast Basin >-, 03 P V ft w a o c ■H w CI o ■H a W •H S 1U00 1200 1000 8oo 6 00 400 200 I960 1970 1980 1990 Year End Figure 11 173 THE CONTROL OF AIR POLLUTION FROM COMBUSION SOURCES By John H. Fernandes Coordinator, Pollution Control Systems Industrial Group Combustion Engineering, Inc. Windsor, Connecticut USA "Man has applied a great deal of his energy in the past to exploring his planet, now we must make a similar commitment in order to restore that planet... The unexpected consequences of our technology often work damage to our environment, now we must turn that same technology to the work of its restoration and preservation." President Nixon has given this challenge to the people of the United States where, as elsewhere in the world, air pollution control has increased in importance with the growth of population and industrial and commercial activity. In the past, science and technology have been encouraged to produce goods and services, while experiencing little restraint. Now, however, the ground rules have changed. In many cases, protection of the environment, so as to maintain biological and ecological balances, has become a major design parameter. This paper will describe various systems and equipment being marketed in the United States today which minimize pollutants emitted from combustion sources. Air pollution, as defined in this paper, is any man-made contami- nation of the atmosphere which harms the natural environment. There are two major categories of air pollution: particulate matter and gaseous pollutants. A further breakdown into sub-categories can be made; however, these two general categories are sufficient to properly dis- cuss air pollution and its control. There are three general methods of controlling air pollutants. They are: reducing pollutant production by process modernization or modifica- tion, collecting the pollutants before they are emitted to the atmosphere, and introducing the pollutants into the atmosphere in such a manner as to properly disperse them so that no harmful concentrations can build up. Minimizing Pollutants by the Use of Modern Systems and Processes Where possible and practical, plant management should first consider a revamping or modernizing program to minimize offending pollutants. This should be investigated before control equipment is considered since the best solution to pollution control is not to generate pollutants in the first place. In keeping with this theme, if proper attention to detail is taken during design, most combustion processes can be operated with a min- imum of pollutants generated. Figure 1 shows a large modern steam generator. It is designed to gen- erate 5,587,000 pounds of steam per hour. Units of this type have the most advanced fuel preparation, fuel burning, furnace, and control systems to 174 insure a minimum of air pollution while reliably meeting steam demand. Another means of limiting air pollution from combustion sources is the selection of nuclear power generating plants (Figure 2) in place of conven- tional fossil-fueled plants. This selection is basically a matter of eco- nomics. Before a final choice is made, many lengthy and complex evaluations are usually made. Of course, air pollution control equipment and systems are available for installation on fossil-fueled plants. These will be dis- cussed later. Normal heating and process steam can be supplied in a very efficient manner with industrial shop-assembled steam generating units. When properly designed, these units can burn a variety of fuels in a manner not offensive to the environment . There are, in fact, 23 solid, liquid, and gaseous fuels in addition to coal, oil, and gas which can be burned in standard industrial boilers. Most of these fuels are considered wastes. Examples are refinery gas, blast fur- nace gas, coke over gas (gases); tars, pitch, sulfite and black liquor (liquids); and bark, bagasse, cellulose (solids). Fuel burning equipment, used to fire these fuels include burners for liquid and gases, Loddby fur- naces, and stokers. Some of these fuels, because of their low heating value, are burned with a supplementary fuel. Figure 3 shows an arrangement for burning one of these waste fuels, sulfite liquor, in a standard shop-assembled boiler. In this application, a Loddby furnace is mounted in place of the regular burner. The Loddby furnace is a cylindrical, refractory-lined unit designed to burn high-moisture content liquid wastes without or with a minimum of aux- iliary fuel, depending on the heating value of the waste being burned. Ca- pacities range from 50 to 150 million Btu per hour. In operation, the wastes are sprayed into the combustion chamber through a burner nozzle and air is admitted tangentially along the length of the furnace creating a cy- clone effect. A differential pressure between the wall and the center of the furnace results in recirculation of a portion of the hot gases back to the burner area, thus completely drying the liquid wastes before they reach the wall area. Another application of the Loddby furnace is shown in Figure 4. Mate- rials such as phenols, cresols, tars, acrylic paints, solvents, waste oil, grease, and a variety of other liquid wastes can be burned in the unit. Besides the Loddby furnace, this system incorporates an incinerator for solid waste burning and an afterburner and spray chamber for stack effluent control. One of the industrial processes long considered a major contributor to the pollution of our environment is paper making. Paper mills give off offensive odors and have many atmospheric discharges which have been known to carry pollutants. To reduce odor and properly clean the stack of a paper mill recovery boiler, Combustion Engineering has developed the air- contact evaporator (ACE) system (Figure 5) . The ACE system minimized odors by eliminating flue gas contact with black liquor. In the system, hot gases leaving the recovery unit econo- mizer are cooled in a regenerative-type laminaire air heater. Incoming clean air is heated in the laminaire heater, then is routed to the cascade evaporator to concentrate the black liquor. From here, it is ducted to the furnace where it is used as combustion air. 175 Air pollution resulting from incineration is a major offender that comes to mind when one thinks of the combustion process. Open burning in dumps and inefficient incinerators are quite common. Because of this, ther^ are those who will react negatively to the proposal of incineration, claim- ing that it is not a true solution in this environmentally conscious societ but merely a transfer of the problem to another media, such as water or air This is a legitimate reaction. In the past, incineration has left a great deal to be desired. Open burning dumps and inefficient incinerators have built a legacy which will be difficult to live down. Equipment is available however, to efficiently and cleanly incinerate solid wastes with only a sterile ash remaining. Figure 6 is an example of a pollution- free small in- cinerator. This incinerator is available in 200 to 1200 lb per hour capac- ities. It works on the principle of pyrolytically reducing the refuse and passing the gaseous effluent through an afterburner to control emissions. For larger capacities, the 3-ton per hour modular unit shown in Figure 7A is available. A detail of the incinerator and scrubber is shown in Figure 7B. In this incineration system, the unprepared refuse is fed onto a reciprocating grate where it is burned in a vigorous manner to a nearly sterile ash with a minimum of putrescibles. The efficient combustion pro- cess minimizes smoke and odor. Combustion gases are routed either to a wet scrubber or to a cooling tower and electrostatic precipitator (where a stear plume my be a problem) for gas cooling and particulate matter removal before being released to the atmosphere. The ultimate in a large and efficient waste disposal system is illus- trated in Figure 8. This unit is installed at a large eastern U.S. indus- trial firm. The plant produces not only large quantities of solid wastes, but also industrial waste sludge. The sludge from the liquid waste clean-uj process is introduced into the flash drying system which uses some of the hot gases from the furnace to dry and prepare the sludge for burning. This drying gas is then re-introduced into the furnace for deodorization. The unit uses prepared refuse as the main fuel. The refuse is passed through a shredder and reduced in size. It is then pneumatically conveyed to the tangential burners located in the four corners of the furnace. The tangential firing method promotes rapid flash drying and ignition which in- sures complete and efficient combustion. The hot gases leave the furnace and pass through the various convection surfaces generating steam for use in the plant. The gases are thoroughly cleansed by an electrostactic pre- cipitator to remove particulate matter. Another similar system is being designed which will fire up to 20 per- cent refuse in a central station utility boiler. For a 125-Mw unit firing 10 percent refuse, for example, this would amount to approximately 250 tons per day of refuse. For the unit under design, the refuse will be conveyed pneumatically to the tangential firing system for suspension burning along with pulverized coal, the normal fuel. The advantages of this system are a reduction in the cost of refuse disposal and a saving in fossil-fuel cost. Use is made of the existing burners, furnace and boiler, fans, air pollution control devices, and ash removal equipment. Additional savings are realized through the use of existing plant facilities such as laboratories, offices, security, parking, etc. The effects of burning ten percent refuse should ve very slight, if not negligible. No significant increase in slagging or corrosion is anticipated there may even be a minor reduction in the potential for low-temperature 176 corrosion due to the reduced sulfur input. Comprehensive tests will deter- mine the exact effects. Collection of Pollutants It is not possible to burn fuel without some pollutants being gener- ated by the combustion process. This section of the paper will discuss the /arious means of collecting pollutants, beginning with the particulate mat- ter. This category includes dust, dirt, ash, and other like pollutants 3efore the problem of collecting these pollutants from the plant effluent :an be really appreciated, one must develop a feel for the size of particles Involved. The commonly used measure of size in particulate collection is ;he micron. Most particulate emissions are much smaller than 44 microns (smallest practical screen size). It becomes quite clear, then, that the naterials under discussion are extremely small, much less than the diameter >f human hair, and they have a very low settling velocity. These particles must be removed from the gas or they will be carried 7ith the gas and dispersed over the countryside. Figure 9 will assist the' reader in understanding the difficulty of settling this material. A ten- nicron particle settles at a velocity of 18 inches per minute in a perfectly »till chamber when acted upon by only gravity and viscous drag. It should je noted, however, that in most combustion processes, this ten-micron is .arge when compared to the average particle. The particles might be a tenth >r a hundredth this size. Mechanical Cyclone Collectors — Mechanical collectors have a long his- :ory of service. The principal representatives of this class of equipment ire the familiar involute cyclones and tubular cyclones. These are devices ;hat achieve particulate removal by means of centrifugal and gravitational forces. As shown in Figure 10, an involute cyclone collector, dust-laden jas enters tangentially thus creating a high-velocity vortex in the cylin- irical portion of the device. This high-velocity, downwardly directed vor- :ex is reversed at the bottom below the cylindrical section. The reversal .s accomplished in such a manner that the separated particles are injected .nto a dust hopper at the bottom of the unit. The reversed gas has an ixially upward component which carries the clean gas to the outlet pipe at :he upper center of the unit. Since this collector, like all mechanical :ollectors, is primarily dependent upon differential inertia, efficiencies rary with particulate size and density, gas temperature, and pressure drop. Figure 11 is a cutaway of a very high-efficiency, controlled-vortex, :ubular mechanical separator. In this unit, the dirty gas enters axially )ver the dual-plane nozzles, proceeding down the cylindrical portion in a peripheral vortex where the majority of the material is transferred to the /all's boundary layer. At the reversing bowl, the axial direction of the rortex is reversed and the particulate matter is stripped to the settling :hamber below. The reversed flow forms a core vortex over the deflecting )ulb and proceeds axially upward to the outlet tube. This core vortex is it a smaller radius and at essentially the same velocity as the peripheral rortex, therefore, it has a greater centrifugal force. This, coupled with :he regenerative skimmer at the top which directs the particles separated )y the core flow to the peripheral vortex for removal, makes this an ex- iremely efficient mechanical collector. The particulate collection effi- :iency for mechanical collectors is normally quite high on larger than 177 20-micron particles, but drops off rapidly as particles in the 10-micron range are encountered. The unit shown in Figure 11 has about the ultimate I in efficiency for mechanical collectors. It maintains a high efficiency well below the 10-micron range. Pressure requirements for mechanical collectors in normal operation are from two to five inches of water. If accurate particulate size data are available, the manufacturer's fractional efficiency curve can be used to predict collection efficiency on a given dust for this class of collec- tor. This value of efficiency can be guaranteed now that the ASME sizinq standards^' have been accepted and are in widespread use in industry. Scrubbers — Scrubbers probably have the widest range of application of the various dust and mist collectors. The dust scrubbing process is ex- tremely complex and no proven theoretical analysis of it has been derived as has been done for the other type of collectors. Many workers have in- vestigated the configurations and methods used in scrubbing particulates from gases and certain important facts are known. First, the dust particle must impact on the water droplet to be removed, and the impaction efficienc is essentially a direct function of the relative velocity between the gas and water droplet and an inverse function of the droplet diameter ^ 2/ ■*' . Therefore, collection efficiency is a function of the power supplied to the unit. This has been verified by Semrau(2) w ho found that efficiency has little relation to scrubber design or geometry, but is primarily dependent upon the properties of the dust and on the contacting power. As true as this is, a properly designed scrubber takes maximum advantage of the power supplied. The scrubbing action is a turbulent, friction-simulating type of action and can easily cover up losses. With proper allowance for the re- quirements of a high relative velocity and the impaction of the particles and droplets, a maximum collection efficiency can be gained for a given amount of energy expended. Figure 12 shows two types of scrubbers. One is the high-velocity cy- clonic spray scrubber where the dust laden gases are introduced into the cyclonic cylindrical section at high velocity and are impinged with a spray from a central manifold. The circulating gas rises through this curtain of water, losing its particulate matter to the water droplets which are slung to the wall and recirculated. The gas proceeds to the neck of the unit where a mist eliminator and anti-spin vanes are installed to dry the clean gas and exhaust them from the system. In the packed scrubber, contact between the gas and the water is a- chieved by passing the dirty gas through a bed of material with water spray entering the packed bed from the top. The gas forces its way through the bed of wet material towards the clean gas exit at the top. The venturi scrubbers illustrated in Figure 13 are examples of very high efficiency scrubbers. A high velocity gas stream is formed at the throat of the venturi where the water is introduced. This breaks the water into very fine droplets for efficient scrubbing. These units would be fol- lowed by some form of droplet collector and mist eliminator to complete the gas cleaning cycle. There are many other types of scrubbers. The ones illustrated here, however, are typical and show the basic scrubber operating principles. Experience has shown that scrubbers can effectively remove dust from gas streams. The wet scrubber also has the ability to remove some of the gaseous pollutants (S0 X , N0 X , etc.) from the effluent if the scrubbing 178 : quid is chemically adjusted to do this. The energy requirements can ex- ed six inches of water for acceptable collection of pulverized coal fly h. In the past, this pressure drop has compared unfavorabley to the much wer values for electrostatic precipitators used on many boilers. Electrostatic Precipitators — The electrostatic precipitator has been ed for over 50 years and has built an enviable reputation. In general, e electrostatic precipitator is one of the most efficient collection de- ces in use today. It operates on a seemingly simple principle, although no means as well understood as might be expected from its simplicity and ng history of use in industry. In the process, the dust particles in a s stream are electrostatically charged by a high-voltage corona discharge BJd are then passed through an electrical field where they are attracted to aigrounded collecting surface (Figure 14) . The performance of precipita- tes, however, is affected by complex relationships with a large number of iterrelated parameters. A review of some of the controlling features of the precipitator indi- cltes that the gas must flow through the unit at low velocity, thereby re- cjiring a fairly large device. One of the significant factors influencing collection efficiency is the strength of the electric field. A voltage flom 50,000 to 100,000 volts is required. Other factors which effect dust Deration to the collecting plates include dust resistivity, gas tempera- tire, sulfur and moisture content of the gas, percentage of design flow, flow distribution, and carbon content of the fly ash. Once the charged particles have been deposited on the collecting fiates, several processes may be used to remove them to the hopper. These i.clude washing, vibrating, and rapping. The dislodged particles are ag- :omerated into lumps of dust and readily settle into the collection hopper, Precipitators can be designed for nearly any efficiency and they can aerate over a broad spectrum of particulate concentrations. The precipi- tator requires a minimum draft loss of only about 1/2 to 1 inch of water =Ld, if operating properly, has the potential of collection over 99 percent :,':' the dust emitted from a combustion process. Sub-micron size particles :m be collected with nearly the same facility as 100-micron particles. j;ius , the precipitator can effectively remove entrained particulate matter I any degree desired and the purchaser can match size and cost of the unit I control requirements. Figure 15 is an illustration of a commonly used electrostatic precipi- tator. The gases enter through the screen on the left, proceed between the :Lates which are arranged vertically, and exit out the right side. Spaced :?tween the plates are the charged wires. The plates are rapped to remove lie particles which fall into hoppers below. Filterhouses — The filterhouse is one of the original cleaning devices, le gas to be filtered passes through fabric filters which are usually ar- inged in a tubular form. The accumulated filter cake on the fabric filter amoves the particulate matter from the gas stream. Various methods are sed to clean the filter, such as mechanical shaking, reverse jet blowing, ig collapse, and reverse flow backwash. Filter efficiencies approach 100 ?rcent, but the overall pressure drop may be as high as 5 to 7 inches of iter. Referring to Figure 16, the dust laden gas enters at the lower left, asses through the filter giving up the dust, and the clean air proceeds p the stack. This particular fabric filter uses the air blast nozzle type 179 of cleaning. The air nozzles at the top are sequenced to blow air which i:| dispersed over a jet deflector and causes the bag to vibrate and lose the collected particulate matter which falls to the hopper and screw conveyor at the bottom. In other types of bag cleaning, such as back flow, there i a temporary cessation of flow in the compartment and the air is reversed through the fabric, causing the vilter cake to be released and dropped to the hopper below for removal. Cloth filtration has the ability to remove 99.9 percent of the partic ulate matter insuring practically complete elimination of plume capacity, thus making it a very desirable air pollution control system. The filter- house has not been considered for application on combustion processes be- cause the cost of the initial filterhouse and bag replacements have been prohibitive. Newer bag materials with longer guaranteed life at higher temperature may eventually open the way to boiler applications. Gaseous Pollutants- -Even after exhaust gases are completely cleaned oj particulate matter, they may still contain offensive gaseous pollutants. These pollutants include SO2 , S03, and No x - There are a number of systems under development in the United States for the removal of sulfur oxides from stack gas emissions. The principal methods being explored are dry anc wet absorption, wet and dry adsorption, and catalytic oxidation. In this discussion, only the most advanced systems will be covered. A fairly obvious solution to the reduction of SO2 and SO3 emitted fronj combustion processes is the use of sulfur-free fuel. The fuel suppliers, however, have not found economical methods of removing sulfur compounds from oil and coal. They have been much more successful in "sweetening" natural gas. Where it is possible to burn this clean fuel, the SO2 problert is eliminated. With oil and coal, the economics justify a thorough review 1 of the methods of collecting pollutants after combustion rather than their 1 removal from the fuel before combustion. Also, there are process modifications which can be explored to further! reduce emissions of harmful gases. Various researchers (4) have found that | low excess air and low flame temperatures reduce the amount of sulfur di- oxide and oxides of nitrogen formed. This can be considered a partial solution to control of these pollutants. In addition, tests (5) have indi- cated that the introduction of inexpensive additives into the furnace with the fuel can reduce the formation of sulfur oxides. At the present time, the Tennessee Valley Authority, as part of the U.S. Air Pollution Control Office's program to demonstrate the feasibility j and cost of processes for reducting sulfur oxide emissions, is conducting s 1 $3 million, 18-month test at their 150 , 000-kilowatt Shawnee generating unit' Powdered limestone is being injected into the combustion chamber where it combines with the gaseous SO2 and SO3 to form solid particulates which can I removed by the unit's electrostatic precipitator along with the fly ash. Tests done by Combustion Engineering indicate that it is possible to remove 20 to 30 percent of the sulfur oxides in this manner. Another program similar to this one was conducted by C-E Air Preheater a subsidiary of Combustion Engineering, in conjunction with the U.S. Depart ment of Health, Education and Welfare. In these tests, an alkaline earth material was fed into the gas stream ahead of a filterhouse. The fly ash and alkaline earth material collect on the fabric filter. The sulfur oxide in the gas, in passing through the filter cake of alkaline material, react with this material, thereby removing S0 2 and SO3 from the gas stream. Re- sults have not been published, but it was possible to remove a meaningful 180 ercentage of the SO2 and SO3 from the gas stream if the filter is operated bove the equilibrium temperature which is just over 600 F. Unfortunately, he success of this particular program must await the development of fabric ilters that can successfully operate at temperatures in excess of the .00 F. Alkalized Alumina Process (Bureau of Mines) — This process^' 7 ' removes ulfur dioxide from flue gas by dry absorption at 625 F. Alkalized alumina ellets, flowing countercurrent to the gas, are used as the absorbing agent. he spent absorbent is regenerated by reduction at 1200 F with hydrogen or eformed natural gas, yielding H2S which is converted to element sulfur in Claus furnace. Work reported to date has been done using a small furnace burning one four pounds per hour of pulverized coal and a pilot plant burning 165 lb f coal per hour. Present estimates indicate capital costs of $10 per kilo- att and net operating cost of 70C to $1.50 per ton of coal. The operating Dsts include overhead charges and a credit for sulfur of $20 per ton. A amber of engineering problems associated with the development of inexpen- ive absorbent preparation methods and reducing gases need to be resolved. Catalytic Oxidation Process — This process involves high-tempera- are flue gas cleaning to prevent catalyst fouling, catalytic oxidation of Z>2 to SO3 at 950 F, and cooling of the SO3 rich flue gas to just above the ew point in an economizer followed by an air preheater. The gas then titers a packed tower and shell and tube heat exchanger where the condensa- ion of the sulfuric acid takes place. There, a stream of cool sulfuric did contacts the gas lowering its temperature to 225 F. Further cooling d 110 F follows. A Brink mist elininator removes the remaining entrained alfuric acid mist. On-stream washing of the mist eliminator removes fly sh build-up. The manufacturer reports that a total pressure drop of 41.5 inches of ater is needed to accomplish 90 percent removal of SO2 while recovering an 2id with a concentration up to 80 percent. The operating costs are based on the sale of 70 percent sulfuric acid, his could involve a considerable marketing problem, depending on the plant Dcation. Appreciable quantities of diluted H9SO4 are used in fertilizer anufacture, but transportation cost may prohibit shipment of dilute acid ore than 25 to 50 miles. The acid could be concentrated but this would ntail additional cost. Combustion Engineering Process --Combustion Engineering has developed nd sold systems to utilities for flue gas desulfurization * ' ' 10, ■ L1 ^ . Two f these units are presently undergoing demonstration. The following ob- ectives for the process were established: A system not dependent upon the sale of a chemical. Reduction of S0 2 and particulate matter to such a level that the stack height and cost could be reduced. Use of a less expensive dust collector than presently used. The potential of increased boiler thermal efficiency without corrosion through lower exit gas temperature levels. 181 5. Reduction of high temperature fire-side coal-ash or oil-ash corrosion. The system developed by Combustion Engineering to fill these require- ments is shown in Figure 17. This system involves the feeding of an alka- line earth additive into the furnace and wet-scrubbing the flue gas leavinc the air heater. The pulverized additive fed into the furnace is calcined, producing a more reactive compound. The calcined particles react with the combustion gases to form compounds of calcium and magnesium, removing 20 tc 30 percent of the sulfur oxides including all of the SO3. The flue gas containing the unreacted SO2 and calcined additive then passes into the wet scrubber. In the scrubber, the calcined additive that has not yet combined with S0 2 in the furnace reacts with the water and re- maining SO2 to form sulfates and sulfites of calcium and magnesium while the water entrainment of the fly ash results in particulate matter removal. The solution containing the reacted materials drains out the bottom of the scrubber to a settling tank (clarifier) or pond. Here the particulate matter settles out. The cleansed flue gas passes through a demister for removal of the remaining water in the gas and is then reheated for induced- draft fan protection. Operation has revealed problems and information not evident during ini tial pilot plant operation. Modifications to these systems have been made in the area of additive injection, gas distribution, and water control. Operation has confirmed that a SO2 removal efficiency equivalent to burning a coal with less than 0.5 percent sulfur can be attained and greater than 99 percent particulate matter removal can be achieved when firing 3.4 per- cent sulfur coal. Oxides of Nitrogen- -Combustion Engineering has done much work in the area of oxides of nitrogen reduction. Oxides of nitrogen are formed at high temperatures by the reaction of the nitrogen in the fuel and the oxy- gen and nitrogen in the combustion air. The concentration of N0 X in flue gas depends on many factors involving burner and boiler design and opera- tion. No generalization can be made regarding the effect of these variable and extensive studies of N0 X emissions^ ' have shown that the exact level of emission from a particular unit cannot be accurately predicted. Most research on oxides of nitrogen emissions has been done with oil and gas fuels. The general ranges for these fuels with horizontal and tan- gential firing are listed in Table I. Data obtained at several plants for oil and gas firing are shown in Figures 18 and 19. At the 2 levels present during conventional operation, a decrease in excess air produces a decrease in N0 X formation. The effect is particularly pronounced for horizontal firing. In recent years, there has been a trend towards operation of oil-fired units at low excess air levels of 2 to 5 percent (0.4 to 1 percent 2 ) insteand of the conventional 10 to 20 percent (2 to 4 percent 2 ) • This has been done to minimize prob- lems associated with the formation of SO3. However, as indicated above, low excess air operation is also beneficial from the standpoint of reducing N0 X . In addition to these methods of limiting N0 X formation, other methods such as overfire air, water injection, recirculation of combustion gases, 182 md combination of these techniques, which reduce flame temperatures, have i favorable effect. Design features found to influence N0 X production are jurner configuration, location, and spacing; furnace configuration; and the !ombustion method used. Control of Air Pollution by Dispersion Once the polluting process has been examined for possible modification ;o reduce pollutants and collection techniques have been applied, the waste jas and remaining pollutants must then be properly introduced into the at- nosphere. If the contaminants are introduced into the atmosphere in such a aanner that local concentrations are not harmful, the atmosphere, which po- ssesses a tremendous capacity for self-purification, will dispose of this jnaterial. This atmospheric cleansing provides particulate fallout as either pree material or the nuclei of water drops, while gases may be absorbed by particulate matter, dissolved in water drops, or condensed before returning :o earth. All of this takes place during the normal movement of air and is* ijuite effective if the atmosphere is not overloaded. Stack height and plume rise, as well as the- amount of pollutant emitted, are important parameters ;Ln determining peak surface concentrations Contrary to popular belief, the tall stack, as compared to a short stack, does not "dump" the same amount pf pollutants onto someone else farther away. Assuming the same mass emis- ision rate, surface concentrations are lower at every point downwind, as the stack height is increased. On the other hand, even a tall stack may be over- Loaded in terms of meeting air quality standards if the amount of polluting ffluent is excessive. The stack is, then, an important part of any system for controlling air jollution. Some researchers have indicated that stacks are the only econom- ically acceptable solution to the SO2 and SO3 problem^ 5 ). High level dis- bersion and dilution is no problem at the present time and this is an effec- :ive solution when coupled with other methods of control. If the quantities }f material requiring disposal continue to increase, a problem may develop and the high stack may prove to be only an interim solution. The concept of atmospheric dispersion may be questioned by those who lave heard of the effects of air pollution during a thermal inversion and Dther adverse meteorological conditions. Thermal inversion of the atmos- phere is one of the most severe natural "road blocks" to proper dispersion, rhis atmospheric condition is defined as a temperature increase with height rather than the normal decrease. (See Figure 20.) This restricts the ver- tical dispersion of the polluted air parcel, and since this condition is learly always accompanied by low wind velocity, it tends to trap and con- centrate pollutants. Normally, this is a natural phenomena occurring in- frequently, and is somewhat peculiar to certain geological locations, al- though they are found in all parts of the United States. Valleys are most susceptible. During clear weather, the earth's surface responds rapidly to ooth daytime heating and radiation of heat from the surface at night. At light, the surface cools qaickly, lowering the temperature of the surface air. Cold air accumulates at ground level causing an inversion because of the warm air trapped above. (See Figure 21.) This type of inversion is established in early evening and can persist for varying lengths of time. Material that is introduced into the atmosphere below the inversion level can be trapped and reach dangerous concentration. If sufficient stack 183 height is used, the plume will break through the inversion emerge above it, and the surrounding countryside will be protected by the isolating effect of the inverted layer. There are many factors to be considered in designing stacks for proper dispersion. Hill tops always present a problem (Figure 22) because air flow patterns about them can cause the pollutant to be returned to the floo: of the valley as well as polluting the area at the top of the hill. In ad- dition to this, the top of the inversion will frequently be at or near the height of the surrounding hill tops. High stacks are very popular today as a means of insuring the disper- sion of pollutants from combustion processes. Stacks 1000-feet high are presently under construction by utilities and this height is augmented by a high efflux velocity of about 75 feet per second. These factors, coupled with the buoyancy of the hot flue gas, produce an effective stack height which is substantially greater than the physical stack height (Figure 23) . (The effective stack height is the sum of the actual stack height plus the height effects due to velocity and buoyancy.) If the effective stack height is great enough, the effluent can "punch through" the inversion and disperse at higher elevations. The ability to pierce the inverted layer and to flow aloft above it and parallel to the earth's surface is a highly effective means of insuring adequate dispersion If extremely severe pollution conditions exist, temporary correction can be made by changing fuel. With a sufficiently high stack, such correction would be needed only occasionally for brief periods. Referring again to Figure 23, it should be noted that minor low-level sources of pollution may be much more serious offenders than plants with high effective stacks. Conclusion Air pollution is emitted to some degree from nearly all combustion activities. The pollutants include the following: particulate matter and gaseous pollutants. These can be controlled to an acceptable degree if modern technology is applied. The first consideration when seeking solutions to an air pollution problem is to evaluate the possibility of revamping the offending combus- tion process. If it is suspected that a new plant will be a polluter when erected, the designers should take advantage of the systems and components that are available today to minimize or eliminate air pollution. Many of these are discussed in this paper. With the exception of some of the sys- tems to control gaseous pollutants, the state of the art is sufficient to limit air pollution. Of course, the equipment must be of good design and properly installed, operated, and maintained. Efforts are constantly being made to improve air pollution control equipment and reduce costs. 184 REFERENCES 1. "Determining the Properties of Fine Particulate Matter," ASME Perform- ance Test Code 28, 1965. 2. Semrau, K. T. , "Dust Scrubber Design — A Critique on The State of the Air," APCA Journal Vol. 13, No. 12, December 1963, p. 587-594. 3. "The Fundamental Mechanism of Dust Collection by Impingement and Dif- fusion," Stairmand, C. J., Heating & Ventilating Engineering & Journal of Air Conditions, Feb. 1953. 4. Fernandes, J. H. , Sensenbaugh, J. D. , and Peterson, D. G. , "Boiler Emissions and Their Control," Presented at the Conference on Air Pol- lution, Mexico City, Mexico, April 28, 1966. 5. Reese, J. T. , Jonakin, J., and Caracristi, V. Z. , "Prevention of Re- sidual Oil Combustion Problems by Use of Low Excess Air and Magnesium Additive," ASME Paper No. 64-PWR-3. 6. Bienstock, D. , Field, J. H. , and Meyers, J. G. , "Removal of Sulfur Oxides from Flue Gas with Alkalized Alumina at Elevated Temperature," Journal of Engineering for Power, Series A, 86, 353 (1964). 7. Maurin, P. G. , and Jonakin, J., "Removing Sulfur Oxides from Stack Gases," CHEMICAL ENGINEERING, April 1970. 8. Bavier, R. F. , "Sulfur-Smoke Removal System," American Power Confer- ence Proceedings, 26, 138 (1964) . 9. Glen, R. A., and Zowadski, E. A., "Catalytic Gas Phase Oxidation and Removal of Sulfur Oxides from Flue Gases," National Power Conference, Cincinnati, Ohio, Sept. 22-25, 1963. L0. McLaughlin, J. F. , and Jonakin, J., " S0 2 Trapped in Full Scale System,' Electrical World, November 13, 1967. LI. Miller, D. M. , and Jonakin, J., "Kansas P & L to Trap Sulfur with Flue Gas Scrubber," Electrical World, March 4, 1968. L2. Sensenbaugh, J. D. , and Jonakin, J., "Effect of Combustion Conditions on Nitrogen Oxide Formation in Boiler Furnaces," ASME Paper No. 60-WA- 334. L3. Report No. 2 of Joint Project on Emissions of Oxides of Nitrogen from Stationary Sources in Los Angeles County, 1961. 185 14. Bartok, W. , Crawford, A. R. , and Skopp, A., "Control of NO Emissions From Stationary Sources," Chemical Engineering Progress, Vol. 67, No. 2, Feb. 1971. 15. Perry, H. , "Methods of Reducing Emission of Oxides of Sulfur from Coal," Proceedings of the American Power Conference, Vol. 27, p. 107 (1965) . BIBLIOGRAPHY Air Pollution, (three volumes) edited by A. C. Stern, second edition, Academic Press, 1968. Recommended Guide for the Control of Dust Emissions--Combustion for In- direct Heat Exchangers, ASME Standard APS-1, second edition, November 1968. Recommended Guide for the Control of Dust Emission of Oxides of Sulfur- Combustion for Indirect Heat Exchangers, ASME Standard APS-2, November 1968. U.S. Department of Health, Education and Welfare Control Techniques, AP Series. 186 TABLE I Fuel Firing ppm N0 X Oil Horizontal 500 to 700 Oil Tangential 200 to 400 Gas Horizontal 300 to 500 Gas Tangential 100 to 200 187 Figure 1: Side Elevation of Modern Steam Generator 188 Figure 2: Palisades Nuclear Power Generating Plant Figure 3: Shop-Assembled Boiler with Loddby Furnace 189 Figure 4: Liquid and Solid Waste Disposal System -S — ► OPEN DAMPERS -M ► CLOSED DAMPERS LAM INAIRE I. P . FAN HEATER AIR — -*» GAS AIR F. D. FAN "Q. EVAPORATOR FURNACE Figure 5: Schematic of Air Contact Evaporator (ACE) System 190 Figure 6: Combustall™ Incinerator Figure 7A: Combustopak™ Incinerator General Layout 191 .REFUSE STORAGE BUILDING OFFICE INCINERATOR STACK SCRUBBER RESIDUE DISCHARGE SETTLING TANK CONVEYOR BUCKET Figure 7B: Combustopak™ Incinerator Detail of Incinerator and Scrubber &■ CYCLONE VENT GAS n. 77.000 LB/HR JL " STEAM, 400 PSIA BOILER l-UHNACt ECON- OMIZER REFUSE 15,000 LB/HR 7,300 BTU/LB ■FLUE GAS TO PRECIPITATOR Figure 8: Flash Drying and Burning System to Dispose of Refuse and Sludge 192 ex. O o o o c_> o > H 1 r-l < 3 o^ Oq: a> -■3r c c^t ii i — o i— p-l ■ r— q 0) O O > to o UJ CO to UJ X o to o o o d CM CM m CM o 6 r ^- ^ ir> ip o — ' o o o o »o o o o ro O 00 O CD o o o CD Ul M CO CO O to UJ to UJ X o z T] DC o u. c/> a. x co CO UJ z -J 2^£ l_ u. CNJ I > O ro O O O O * N O * CO o CNJ O ro c\J ro O O O O =1 o o o < oc _l < LU 0- *x >- CO t < o .-» o o ro O O > < O u. o UJ 0. CD ro o UJ >< ?5 jUJ to I- x ~ t- a. UJ CO CO I LU N CO to ■H -C to C o •H id £ >i -P ■H o H c -r-l r-i ■P +J 01 CO CD N •r-l CO at u 01 •H 193 DUAL PLANE NOZZLE REGENERATIVE SKJMMER TO SETTLING CHAMBER REENTERING CONVEYING FLOW PERIPHERAL VORTEX DEFLECTING BULB REENTRY PORTS Figure 11: Twin Cyclone Mechanical Dust Collector ANTI-SPAN VANES AND MIST ELIMINATOR CYCLONIC SPRAY SCRUBBER ENTRAINMENT SEPARATOR BAFFLES DUSTY GAS IN- — CLEAN GAS OUT TYPICAL PACKING BED TYPICAL WATER SPRAY .— WATER INLET DIRTY WATER OUT PACKED SCRUBBER Figure 12 Cyclonic Spray Scrubber (Top) and Packed-Bed Scrubber (Bottom) AIR INLET WATER INLET AIR ^OUTLET AIR INLET WATER INLET AIR OUTLET WATER OUTLET DRY VENTURI Figure 13 WET VENTURI Venturi Scrubbers 194 COLLECTOR ELECTRODE AT POSITIVE POL ARITY <$ INLET DIRTY GAS FLOW UNCHARGED- PARTICLES ELECTRICAL FIELD , UAO , Pn CHARGED PART DISCHARGE ELECTRODE AT NEGATIVE POLARITY CLES 00 /^V ,*? ,?SP i\ CLEAN CZ/GAS EXIT PARTICLES ATTRACTED TO COLLECTOR ELECTRODE AND FORMING DUST LAYER HIGH TENSION SUPPLY FROM RECTIFIER Figure 14: Principle of Electrostatic Precipitator Operation Figure 15: Cut Away of Typical Precipitator 195 PLENUM CHAMBER BAG CLAMPS ,> JET DEFLECTOR' COLLECTOR HOUSING FILTER BAG DUST LADEN AIR > ^^-—^ AIR NOZZLES -. ^ INLET T III ::jf /\ l OUTLET FILTER ASSEMBLIES! ,g " . ■ S SCREW CONVEYOR AIR-LOCK VALVE CLEAN AIR BAG CAGE MAGNEHELIC DRAFT GAGE HOPPER o" Figure 16: Ray-Jet Fabric Filter Dust Collector LIMESTONE SUPPLY COAL SUPPLY PULVERIZER RECYCLE SYSTEM IS MAKE UP WATER TO ASH DISPOSAL POND Figure 17: Schematic of C-E SO and Dust Removal System 196 EFFECT OF EXCESS AIR, OIL FUEL EFFECT OF EXCESS AIR, GAS FUEL 700 PLANT C HO *IZOt> ITAL FIRING oOO 500 — a/ A PLA NT G TANGEN TIAL FIRING ^ m* 1 00 700 2 a. 300 PLANT FIRING A — Q HORIZONTAL D- O HORIZONTAL F — ^ TANGENTIAL r 0^ ^ * n PERCENT 2 PERCENT Q, Figure 18: Effect of Excess Air, Oil Fuel Figure 19: Effect of Excess Air, Gas Fuel INVERSIONS NORMAL LAPSE RATE 5.5 F PER 1000 FT. 20 40 60 TEMPERATURE- F HOW INVERSIONS ARE FORMED ON CLEAR NIGHTS IN VALLEYS RADIATION COOLS EARTH S SURFACE MORE RAPIDLY THAN UPPER AIR COOL AIR FLOWS DOWNWARD ALONG SLOPES AND ACCUMULATES IN THE VALLEY WARM AIR COLD AIR LAYER OF'WARM AIR IS TRAPPED BY COLDER AIR ABOVE AND TRAPS COLO AIR BELOW, CAUSING AN INVERSION Figure 20: Inversions Figure 21 How Inversions are Formed on Clear Nights in Valleys 197 ■.-3>V WIND DIRECTION I I I I I I I ' o I I I I I Figure 22: Effect of Hills on Air Flow Patterns VELOCITY AND BUOYANCY HEIGHT EFFECTIVE HEIGHT WIND DIRECTION Figure 23: Effective Stack Height Equals Actual Stack Height Plus Velocity and Buoyancy Factors 198 THE CONTROL OF INDUSTRIAL AIR POLLUTION SOURCES By Alleu D. Brandt, Manager, and David M. Anderson, Assistant Manager Environmental Quality Control Division Bethlehem Steel Corporation Bethlehem, Pa. USA Air pollution control from industrial sources in the U.S.A. was prac- ticed sparsely until about 20 years ago. The early application of air pol- lution control facilities related principally to isolated sources having huge emission rates which created severe problems of local nature. The problems were either because of odor, surface discoloration or some other * particularly objectionable characteristic such as denuding the nearby coun- tryside or creating tremendously high dust fall rates. There is no need here to recount those episodes; suffice it to mention the Trail BC smelter case v 'as one of the very early incidents, and the many paper-making commu- nity odor problems which have been of concern during more recent times. In our judgment, it was the Donora^' incident in 1948 which alerted all segments of society in the U.S.A. to the serious health hazard that can be created whenever severe meteorological conditions exist over a local area which includes major sources of pollutants, the principal ingredients of which frequently are sulfur oxides and fine particulates. To be sure, that episode was unique, but it made many, many persons in the U.S.A. conscious of the potentialities that exist in numerous locations if adverse meteoro- logical conditions should persist for days. The anticipated result has come to pass. Society, government, indus- try, public health-oriented personnel and many other groups became concerned, and active . The degree of concern and rate of activity was further acceler- ated by the realization that conditions were becoming rapidly worse as a result of the combination of a population explosion and an unprecedented in- crease in the standard of living in the U.S.A. Both the population explo- sion and the increase in the standard of living promised ever-increasing air pollutant emission rates, including previously unheard of types of pollutants from more and more sources. The past 20 years in the U.S.A. have seen major changes take place. Laws relating to air pollution control have been enacted and amended rapidly by and at all levels of government; society has become conscious that the private citizen as well as industry, the automobile and the municipal incin- erator all contribute to the problem. One important result has been that the rate of application of air pollution control facilities and process changes to achieve emission reduction have catapulted to new highs year by year, especially during the past three to five years. Much remains to be done, but the need to do and the will to do even more now are evident to a degree never experienced previously in the U.S.A. Even though industry in the U.S.A. continues to be as competition-minded as ever, industrial cap- tains across the nation have made it abundantly clear in the past year or two that continued degradation of the environment must be stopped, and that 199 the well-being of society — the quality of the environment—has top priority even if it conflicts with other business considerations. Significantly, efforts to control air pollution have increased in the past two years, a period during which profits have fallen. According to a recent Federal government pro jection ^' , the total investment required to control air pollution from the major process industries between 1970 and 1976 is approximately 3.9 billion dollars. The annualized cost, including operating and maintenance costs, is approximately 1.1 billion dollars (see Table I). These figures do not include, however, the untold expenses in- curred before 1971. Let's take a look at the major pollution sources in the United States. Table II shows the relative quantity of total air pollutants (particulate and gaseous combined) , emitted from the major pollutant classifications in 1968^ 4 '. Note that the industrial portion, 30 million tons, is only 14% of the total quantity of emissions. This emission rate, and the other emission rates mentioned in the table, are the amounts still to be controlled and do not include the great amounts of potential emissions which currently are being controlled. Particulate matter^' 5 ' is the major pollutant released from most in- dustrial processes (see Table III). Gaseous pollutants, such as sulfur di- oxide , hydrocarbons , and carbon monoxide , are problems for a few specific industries (see Table IV) . Fluoride (particulate and gaseous) emissions are also a problem for some industries. Because particulates are the number one industrial problem, we will describe the control efforts of each major industry in order of decreasing emission rate as estimated for 1967 (see Table III) . The year 1967 is used as the baseline year to compare pollution control efforts in the United States in conjunction with passage of the 1967 amendment to the Clean Air Act. Efforts to control gaseous emissions will be described where applicable to a specific industry. Particulate emissions occur in a variety of forms including dusts, fumes, mists, and smoke. Dust particles are relatively large as compared to fumes, some mists, and smoke, and generally are released from material crushing and handling operations. For the purpose of this paper, fumes are condensed metallic vapors; mists are liquid particles suspended in gas (us- ually air) ; and smoke is small particles of carbon suspended in the gaseous products of fuel combustion. In discussing air pollutants from industrial sources it is important to always keep in mind the nature of the source, whether it be a captive source such as the stack from a metallurgical furnace or the vent from an enclosed chemical process, or whether it be a fugitive source such as a stream or cloud of dust-laden air or gas which is not contained. Typical examples of fugitive sources are dust from blasting operations in quarries and smoke from the charging of conventional vertical-slot ovens used in the by-product method of making coke from coal. When one is dealing with a captive source of air pollutant, control can be achieved by removing the pollutant from the confined or contained gas (or air) stream of which it is a part. Thus controlling a captive source is purely a problem in gas (or air) treatment, the technology for which fre- quently is available, especially as regards the removal of particulate mat- ter from stack and vent gases. However, control of a fugitive source is much more evasive because technology is frequently not available for captur- ing or containing certain fugitive sources. Before such clouds of fugitive 200 amissions can be cleaned, they must be converted from fugitive to captive sources. Keeping haulageways or roadways from dusting in freezing weather; preventing settled dust from being refloated by wind gusts; containing the smoke, other particulate matter and gaseous pollutants which escape during charging of coke ovens; and preventing dust clouds from being generated tfhen blasting or when farming during dry weather are problems still needing much improved control technology before they are amenable to control. Control of particulate emissions from captive sources may be achieved through basic process changes and operational changes, or through particu- late removal equipment. Treatment facilities include centrifugal separa- tors, fabric filters, scrubbers, and electrostatic precipitators. Centri- fugal separators (and some types of scrubbers) act as primary collectors and have low collection efficiencies for particles smaller than 5 microns. Fabric filters, high-energy (venturi) scrubbers, and electrostatic precipi- tators, on the other hand, are high efficiency collectors which can be made effective even against submicron particles. In many cases adequate control jof industrial sources can be attained only through use of the high effi- ciency collectors. Sometimes, depending upon the nature of the source, com- binations of process- changes or of collectors are needed to achieve a satis- factory effluent. It may be useful at this point to review the basic control mechanisms of the various collectors. Centrifugal collectors utilize centrifugal force created by spinning a particulate-laden gas stream to separate the particu- lates from the carrier gas Fabric filters remove particulates mostly by interception and impaction of the particulates initially with the fabric and later with the resultant dust cake formed on the upstream face of the fabric while the carrier gas passes through the fabric. Venturi scrubbers remove particulates by impacting the particles on water droplets and removing the particulate-laden water droplets in a mist eliminator. Electrostatic pre- cipitators charge the particles with electrostatic charges and collect them on grounded surfaces. Table III lists the major industrial particulate emission sources in the U.S.A. Surprisingly, the stone, sand and gravel industry is the largest single industrial source of particulate (dust) emissions. The dust occurs mostly during crushing and grinding and also during quarrying, transporta- tion of materials, and size classification. In many cases the sources are not stationary and the emissions often occur intermittently, both of which conditions increase the difficulty of control. Fugitive sources can often be reduced by changing plant layout and material handling practices. The use of water sprays at critical points is the simplest and least expensive method of controlling dust from these sources, though this procedure is fraught with difficulty in sub- freezing weather. Crushing and grinding operations in many industries other than the stone, sand and gravel industry also create problems. Most are amenable to control by proper hooding or other enclosures, exhaust ventilation of the sources and appropriate collectors. Where applicable, water sprays often provide the easiest solution. The grain milling and handling industry which processes grain into flour, livestock feeds, and cereals is the second largest industrial source of particulate emissions. The dust emitted at the cleaning, milling, and handling operations of grain terminal elevators constitutes the majority of the problem. In many cases the value of the collected dust is suffi- cient to pay for the collection facilities. Dust generated from milling 201 and handling of livestock feed often is uncontrolled because the feed is less valuable. The dust can be captured by exhausting air from hoods at transfer points and from grain elevators and cleaning the exhaust streams in fabric filters. The iron and steel industry is the largest single industrial source of captive-type particulate emissions. Consequently, we will treat it in greater depth than any other industry source and it will serve as an example! of the complex problems which industries face in controlling air pollution. Iron and steel industry particulate emissions include dusts, fumes, smoke and mists. Dust is generated from some fugitive sources such as pre- viously described, and from plants which sinter a mixture of ore, flue, dust, lime, iron scale, and coke breeze into a product acceptable for charging into the blast furnaces. In the process, the mixture is located on a moving grate, and the air which is pulled through the mixture to burn the fuel becomes hot, and laden with dust, moisture, and some sulfur dioxide The resultant windbox effluent is corrosive and abrasive and until recent years has been cleaned almost exclusively by centrifugal separators, elec- trostatic precipitators having been used in only a relatively few instances. Precipitators installed in recent years often have performed rather poorly. Consequently, scrubbers and fabric filters now are being investigated for sinter plant windbox application. They were not considered previously largely because fabric filters are susceptible to clogging by moisture, and scrubbers create water pollution problems in addition to being susceptible to corrosion and abrasion. The decision as to what type of collector is most suitable is not yet clear. It will vary from plant to plant depending upon the nature of the feed materials. Control of the dust released from the discharge ends of the sinter strands in sinter plants and certain subsequent conveyor transfer points and accessory processing operations has been accomplished reasonably well with available technology. Only within the past year or two has the dust generated by air-cooling the hot sinter come under consideration. While technology is available for controlling such dust the magnitude of the dust-laden air streams is so large that the cost of control of these dust- producing operations will be very high in terms of dollars per unit of par- ticulate pollutant per hour recovered. Fume is generated in ironmaking and steelmaking furnaces. Iron is produced in blast furnaces by smelting iron ore. Particulates contained in the off gas from the blast furnace operation are now and have for years been controlled well in order to permit using the blast furnace gas as a fuel, even though it is a very low grade fuel. Venturi scrubbers and/or wet-type electrostatic precipitators are utilized as the final stage in the gas- cleaning systems of blast furnaces. Steel is produced in open hearth, basic oxygen, and electric furnaces. The raw materials are principally iron, either hot metal or "pigs," and scrap. Limestone, iron ore and alloying materials are used as required. Scrap is the principal raw material in most electric furnaces and in many "cold charge" open hearths. Every basic oxygen furnace constructed in the U.S.A. has been provided with effective air pollution control systems in which precipitators or high- energy scrubbers serve as the particulate collectors. For the second half of 1970, more than half of the steel made in the U.S.A. was made in basic oxygen furnaces. The stack gases from all except a very few oxygen-lanced 202 jpen hearth furnaces are now being cleaned effectively. However, because ;onventional and frequently "cold charge" open hearth furnaces create a com- paratively small amount of particulate matter, and because of economics, such furnaces have seldom been controlled in the past. Many are now being retired or replaced by more up-to-date furnaces such as basic oxygen fur- iiaces and electric furnaces. Particulate emissions from electric furnaces are more difficult to con- trol satisfactorily than from other steelmaking furnaces, because practically all electric furnaces can be charged only when the furnace top is swung aside. Since fume control during melt down, refining, etc. is achieved in many fur- naces by direct evacuation of the furnace chamber through a connection in the furnace top, that system is inoperative during charging. As a result, the trend today is toward complete building ventilation (evacuation) , usually [through large compartmented hoods rather high above the furnaces (so as not to interfere with the bridge-type service cranes) . While this solution to the problem is an effective one, it is inherently very inefficient and costly. All of the pollutants that are permitted to escape into the build- ling housing the furnaces are diluted rapidly in the room air. Consequently, the amount of dirty air exhausted from the buildings which must be cleaned before discharge to the outside air is many times what it would be if con- trol could be applied at the source. For example, a system having a capac- ity of about 100,000 cfm will control effectively the fumes generated in several electric furnaces during melt down, refining, etc., but the capac- ity of the system for the same furnaces must exceed 1,000,000 cfm if open furnace top charging is done, during which time the particulate pollutants escape from the furnace into the building. This large increase in capacity is needed even though the charging operation may account for less than 10% of the total particulate matter generated by the furnaces. Baghouses with glass fabric filters are the collectors normally used for direct evacuation systems, and baghouses with dacron fabric filters are normally used for building ventilation systems. A combination of coal dust, hydrocarbon vapors, particulates, mists and smoke is emitted from coke plants, most of which in the U.S.A. are owned by iron and steel companies. Coke, a primary fuel for the blast furnace, is produced in vertical slot ovens through the destructive distillation of bituminous coal. Usually between 50 and 100 slot ovens constitute a coke oven battery which is shaped somewhat like a loaf of bread, each slice rep- resenting an individual oven. Coal is charged through openings in the top of each oven and coke is pushed from one end out the other. Emissions occur from leaks, coal charging and coke pushing. Adequate control of these emis- sions is not possible with today s technology. We are confident, however, that coke oven emission control will be technically feasible within the next few years. The entire steel industry, separately and trhough the American Iron and Steel Institute jointly with the federal government, is currently building or completely modifying several full-scale coke batteries with sim- ilar, though each somewhat different from the other, pollution control sys- tems . The kraft (sulfate) pulp industry emits particulates in the form of process chemicals. Pulp is manufactured from wood for use in making paper and related products. Wood chips are cooked in a liquor which separates the cellulose from the lignin. Pulp is then produced from the cellulose. The lignin is burned as a fuel in the recovery furnace and the chemicals 203 are recycled. Process chemicals are released from recovery furnaces and smelt dissolving tanks, lime is released from recovery kilns, and char is released from bark boilers. Particulate emissions from recovery kilns are controlled with electrostatic precipitators; emissions from smelt dis- solving tanks and recovery kilns are controlled with scrubbers and particu- late emissions from bark boilers are reduced with centrifugal separators. The asphalt batching industry is also an important source of particu- late emission. Asphalt batching is the production of a road surface paving mixture made from hot asphalt and stone aggregate. Most of the particulates (dust) are emitted from the rotary dryers which pre-dry and pre-heat the stone aggregate before mixing it with the hot asphalt prior to the batching process. The drying and heating is normally done in rotary kilns which are rotating horizontal cylindrical furnaces slightly sloped so that the stone rolls by gravity from the charging to the discharging end. General practice is to reduce emissions by 80% or more with centrifugal separators. Scrubber are necessary in order to accomplish adequate control. New plant capacity must be greater than 400 to 500 tons/day to economically allow for scrubber control. The cement and lime industry are similar prcesses with similar emission problems. For both cement and lime, limestone or other calcium-bearing rock is calcined to produce calcium oxide. Both cement and lime are calcined in rotary kilns similar to those used by the asphalt industry. The capacity of cement kilns is as much as 10 times greater than the capacity of lime kilns. For both industries a large amount of dust entrained by the kiln gases must be controlled. For lime kilns, fabric filters or scrubbers are normally used, while for cement kilns, fabric filters or electrostatic precipitators are the usual choice. The difference in selection is a result of compara- tive economics for large cement kilns vs. small lime kilns. The iron foundry industry, a large, diversified and scattered industry, produces castings such as machine and automobile parts, and in doing so, generates large amounts of particulate emissions. Over 90% of all the iron used by the industry is produced in cupolas. Cupolas are vertical cylin- drical furnaces in which coke is burned in direct contact with the metal charge. The cupolas emit a large amount of particulate matter which consists of coke, oil, fume and lime dust. Most cupolas are adequately controlled in the U.S.A. Proper control equipment for cupolas in many instances is more expensive than the cupolas themselves. Some jobbing foundries which operate cupolas intermittently cannot afford to adequately control emissions and are, therefore, going out of business. Many foundries of larger industries are consolidating or centralizing cupolas operation in order to eliminate many of the cupolas. Furthermore, some cupolas are being replaced by elec- tric arc and electric induction furnaces. Although both high efficiency scrubbers and fabric filters have been considered as effective collection devices for cupolas (where economically feasible) , to our knowledge only scrubbers have been used on cupolas without difficulty. Cupolas also emit large quantities of carbon monoxide. This gas can be eliminated at comparatively little cost by afterburners. The coal cleaning industry is an important source of particulate (dust) emissions. The coal is cleaned of undesirable materials found in raw mine coal by washing the coal with air or water. The major amount of dust comes from either flash driers, f luidized-bed driers, or pneumatic cleaners. Scrubbers rather than fabric filters are preferred as control devices to avoid the fire and explosion hazard which exists with coal dust. 204 The petroleum refining and storage industry is a source of particulates, arbon monoxide, sulfur oxides, and hydrocarbons. Particulates, carbon mo- Dxide, and hydrocarbons are emitted from the catalytic cracking units. The articulates are catalyst fines which are entrained in the off gases from ne catalyst regenerator. Particulate control is best accomplished by elec- trostatic precipitators. The carbon monoxide and hydrocarbons released in tie exit gas of regenerators are generally burned in waste heat boilers. Large amounts of sulfur oxides are emitted from the refineries' prac- ice of burning, as fuel, the low-grade, sulfur-bearing gas and liquid fuels hich are generated in the refining processes. Sulfur oxides emission con- rol can best be accomplished by removing the sulfur compounds from the fuel rid feed stock by catalytic hydrogen treatment. Hydrogen treatment produces ydrogen sulfide which can be scrubbed from the gas stream, stripped from jhe scrubbing solution by heating, and converted to sulfur by conventional rocesses . Most hydrocarbon emissions are evaporation losses from storage tanks nd from the loading of tank trucks. Evaporation losses during storage are educed trhough the use of floating storage tank roofs, pressure tanks and - ecovery systems. Vapors emitted during the loading of trucks can be col- ected and recovered in a vapor recovery system. The sulfuric acid industry is a source of particulate (in the form of ulfuric acid mist) and sulfur dioxide emissions. Most sufuric acid is pro- ceed by burning sulfur or pyrite to produce sulfur dioxide which is cata- lyzed to sulfur trioxide which in turn is absorbed in weak acid. Acid mist mission can be readily controlled with either an electrostatic precipitator ;r mesh type mist eliminators. Sulfur dioxide which remains unconverted and ubseguently is emitted, can be controlled by a secondary absorption column. Particulate control practices of the non-ferrous metallurgical indus- ries which produce aluminum, copper, zinc and lead need not be described ere inasmuch as the fume sources and control techniques are similar to hose of the iron and steel industry. The primary non-ferrous metallurgical industry, however, is the largest ndustrial process source of sulfur oxides, and the second largest source of luorides. The sulfur oxide emissions result from the smelting of copper- ;inc, and lead-containing ores. Sulfur oxides can be significantly reduced y passing the captured gas through a sulfuric acid plant. Sulfur oxide •missions from the acid plant, however, may still be significant and require further scrubbing. Fluoride emissions (a combination of particulate and gaseous fluoride) 'esult from the production of primary aluminum in reduction cells. The :ell gases are captured either at the point of evolution by separate hoods iver the individual cells, or at the roof monitor by one large hood which :aptures the entire cell room ventilation flow. In the past, fluoride emis- sions have been reduced by greater than 90% by passing the captured gas hrough centrifugal collectors followed by low-energy scrubbers. The fluor- .de problem is completely controlled in new plants, however, by cleaning the lases in a fluidized bed followed by fabric filters or floating bed scrub- iers. The brick and tile industry is the largest source of fluoride emissions n the U.S.A. Gaseous fluorides are emitted during heating the brick and :lay products in burning kilns. Emission data are sketchy and fluoride con- rol has not been practiced. Emissions can be reduced to very low levels, towever, by scrubbing the kiln gases with water. It should be noted that 205 fluoride emissions do not occur, of course, where the clay does not contain fluorides. Other less important industrial sources of particulate emissions in the U.S.A. include the phosphorous and phosphate fertilizer industry, the rubber! industry, and many other less significant sources. Furthermore, there are many local problems resulting from a variety of specific pollutants such as lead and a variety of malodorous chemicals. Many of these sources must also be controlled. There is a very good chance that most of the above-mentioned pollution sources in the U.S.A., with the possible exception of certain problem sources for which control technology is not currently available, will be controlled to a much greater extent than today within the next five to ten years. Great strides have already been made, and by the year 1980 it is expected the emis- sion rate from industrial air pollution sources in the U.S.A. will be reduced by at least 90% from 1967 levels. 206 TABLE I Projected Control Costs Between 1970 and 1976 Industrial Process Sources- Control Costs 2 (Millions of Dollars) Investment-' Annual^ Unknown Unknown 463 164 981 507 73 30, 15 12 110 30 11 15 317 108 13 5 162 7 1,080 176 41 62 22 321 127 39 13 2 1 41 12 1 1 Stone, Sand and Gravel 5 Grain Handling and Milling Iron and Steel 6 Kraft (Sulfate) Pulp Asphalt Cement Lime Iron Foundries Coal Cleaning Petroleum Refineries Petroleum Products and Storage Sulfuric Acid Manufacture Secondary Non-ferrous Metallurgy- Primary Non-ferrous Mettalurgy Elemental Phosphorous and Phosphate Fertilizer Rubber Brick and Tile 7 Varnish Total 3,867 1,095 1 See Reference 3. 2 Estimated for 298 selected metropolitan areas. The costs should not be considered as the total cost for achieving clean air, neither in the 298 areas nor in the nation. ■a J Total expense of purchasing and installing control equipment. 4 Includes interest on funds, taxes where applicable, insurance premiums, depreciation, operating expense, and maintenance costs. 5 See Reference 5. 6 Does not include the cost to control coking emissions and blast furnace emissions . 7 Cost to control fluoride (particulate and gaseous') emissions. 207 TABLE II Air Pollution Emissions in the United States, 1968 1 Transportation Fuel consumption in stationary sources INDUSTRIAL PROCESS Solid waste disposal Forest fires Miscellaneous Emission Rate (tons/year x 10 6 ) 90 45 30 11 17 21 214 Percent of Total 42 21 14 5 8 10 100 See Reference 4, 208 TABLE III Estimated 1967 Particulate Emission Levels and Projected 1976 Particulate Emission Levels Industrial Process Sources- Quantity of Emission (thousands of tons/year) 1967' 1976 Stone, Sand and Gravel- 5 Grain Handling and Milling Iron and Steel Kraft (Sulfate) Pulp Asphalt Cement Lime Iron Foundries Coal Cleaning Petroleum Refineries Sulfuric Acid Secondary Non-ferrous Metallurgy Primary Non-ferrous Metallurgy Elemental Phosphorus and Phosphate Fertilizer Rubber 600 952 490 633 522 400 344 217 160 96 72 12 10 6 1 Unknown 59 89- 119 40 24 28 31 17 32 55 3 2 See Reference 4. ^ 1967 is used as the baseline year in conjunction with passage of the 1967 amendments to the Clean Air Act. •* See Reference 5. Also, year of listed emission rate unspecified. 209 TABLE IV Estimated 1967 Gaseous Emission Levels and Projected 1976 Gaseous Emission Levels Quantity of Emission (thousands of tons/year) Industrial Process Source- 1 - 1967 2 1976 Sulfur Dioxide: Primary Non-ferrous Metallurgy - Copper 2 940 - Zinc 263 - Lead 642 Petroleum Refineries 2 100 Sulfuric Acid Manufacture 750 Carbon Monoxide: Petroleum Refineries 6 200 Iron Foundries 3 200 Hydrocarbons : Petroleum Products and Storage 1 100 Petroleum Refineries 932 Varnish Manufacture 2 294 16 96 1,270 129 331 205 407 528 1 See Reference 4. 2 1967 is used as the baseline year in conjuction with passage of the 1967 amendments to the Clean Air Act. 210 REFERENCES 1. Lathe, F. E. and McCallum, A. S. "Effect of Sulfur Dioxide on Vegeta- tion," Chapter 7, p. 154, National Research Council of Canada, Ottawa, 1939. 2. Stern, A.C. "Air Pollution," 2nd ed., Vol. I, Academic Press, New York, 1968. 3. Report of the Administrator of the Environmental Protection Agency to the Congress of the United States, "The Economics of Clean Air," U.S. Government Printing Office, Washington, March 1971. 4. First Annual Report of the Council on Environmental Quality, "Environ- mental Quality," U.S. Government Printing Office, Washington, August 1970. 5. Midwest Research Institute, "Handbook of Emissions, Effluents and Con- trol Practices for Stationary Particulate Pollution Sources," National Air Pollution Control Adminstration Contract No. CPA 22-69-104, Novem- ber 1, 1970. 6. National Air Pollution Control Administration, "Control Techniques for Particulate Air Pollutants," Publication No. AP-51, U.S. Government Printing Office, January 1969. 7. National Air Pollution Control Administration, "Control Techniques for Sulfur Oxide Air Pollutants," Publication No. AP-52, U.S. Government Printing Office, January 1969. 8. National Air Pollution Control Administration, "Control Techniques for Carbon Monoxide Emissions from Stationary Sources," Publication No. AP-65, U.S. Government Printing Office, March 1970. 9. National Air Pollution Control Administration, "Control Techniques for for Hydrocarbon and Organic Solvent Emissions from Stationary Sources," Publication No. AP-68, U.S. Government Printing Office, March 1970. 10. The assistance of T. E. Kreichelt, Assistant Air Pollution Control Engineer, Bethlehem Steel Corporation, in the preparation of this paper is gratefully acknowledged. GENERAL REFERENCES Air Pollutant Emission Factors, U. S.D. H. E.W. , Environmental Health Service, NAPCA, Washington, D.C., April 1970. Anderson, F.G. and R. L. Beatty, "Dust Control in Mining, Tunneling, and 211 Quarrying in the United States, 1961 through 1967," United States Depart- ment of the Interior. Kiesner, J., "GFDNA Air Pollution Symposium Studies Dust Emission, Con- trol," Feedstuffs , January 21, 1968. Lownie, H. W. , and J. Varga, "A Systems Analysis Study of the Integrated Iron and Steel Industry," Battelle Memorial Institute, Contract No. PH 22- 68-65, May 15, 1969. Barnes, T.M., and H. W. Lownie, "A Cost Analysis of Air-Pollution Controls in the Integrated Iron and Steel Industry," Battelle Memorial Institute, Columbus, Ohio, May 1968. Dancy, T. E. , "Control of Coke Oven Emissions," 78th General Meeting of American Iron and Steel Institute, May 27, 1970. Kreichelt, T. E. , D. A. Kemnitz and S. T. Cuffe, "Atmospheric Emissions from the Manufacture of Portland Cement," U. S. Public Health Service Pub- lication No. 999 AP-17 (1967) . Hildebrant, P., et al., "Air Pollution from the Kraft Pulping Industry," A Report to Washington Air Pollution Control Board, prepared by Office of Air Quality Control, Washington State Department of Health, Seattle, Wash- ington, May 1969. Landry, Joseph E., and Daniel H. Longwell, "Advances in Air Pollution Con- trol in the Pulp and Paper Industry," TAPPI, June 1965. Lewis, C. J., and B. B. Crocker, "The Lime Industry's Problem of Airborne Dust," Journal of the Air Pollution Control Association , 19, p. 31 (1969). Systems Study for Control of Emissions — Primary Nonferrous Smelting Indus- try," Final Report, Contract PH-86-65-85, National Air Pollution Control Administration, Arthur G. McKee & Company, June 1969. "Air Pollution from the Primary Aluminum Industry, " A Report to Washington Air Pollution Control Board, Office of Air Quality Control, Washington State Department of Health, Seattle, Washington, October 1969. "Atmospheric Emissions from Wet-Process Phosphoric Acid Manufacture," National Air Pollution Control Administration Publication No. Ap-57, Raleigh, North Carolina, April 1970. Friedrick, H. E. , "Air Pollution Control Practices and Criteria for Hot- Mix Asphalt Paving Batch Plants," Air Pollution Control Association, Paper No. 69-160, June 1969. American Foundrymen's Society, Foundry Air Pollution Control Manual , Des Plaines, Illinois, 1967. Kane, John M. , "Foundry Air Pollution A Status Report," Foundry , Novem- ber 1968. 212 THE STATUS OF INSTRUMENTATION IN AIR POLLUTION CONTROL By Robert E. Neligan Acting Director, Division of Applied Technology Bureau of Stationary Source Pollution Control Air Pollution Control Office Environmental Protection Agency Research Triangle Park North Carolina, U.S.A. ntroduction Instrumentation used in air pollution control activities may be ivided into three broad areas of activity: aerometric, that is the easurement of pollutants in the ambient air, source emission testing, the ampling or monitoring of emissions from stationary sources; and the measure- ;ent of pollutants from mobile source, automobiles and trucks. Surveillance of air quality and the measurement of emissions from tationary sources has become an increasingly important function of any air ollution control agency. Initially the agency must determine the magni- .ude and scope of its air pollution problem, i.e., the extent to which air uality standards are being exceeded. This data and data collected through .n emission inventory may then be used to fit a diffusion model, or used in roportional reduction or roll-back techniques. Either technique must be :sed to develop an effective emission control plan. Following the adoption f emission regulations, atmospheric surveillance is required to evaluate he progress toward the attainment of air quality goals. Additionally for hose areas prone to the occurence of periods of high air pollution (epi- odes) surveillance becomes a vital part of any Emergency Action Plan. Newly enacted Federal legislation in the United States requires that he Federal Government establish air quality standards for air pollutants, his has been accomplished for six pollutants: particulate matter, sulfur xides, carbon monoxide, hydrocarbons, nitrogen oxides and oxidants. Now hat these air quality standards have been established, each State must .evelop a state-wide plan to control these air pollutants to the level dictated by the air quality standard. The plan must include provisions for he establishment and operation of appropriate devices, methods, systems ind procedures necessary to monitor, compile and analyze data on ambient iir quality. Thus, in the United States, air pollution control agencies at all evels of government are now conducting atmospheric surveillance activities o measure a wide range of particulate and gaseous pollutants. A survey of hese activities (Table I) provides an estimation of the types of pollutants >eing measured as well as the number of devices presently in operation, his listing includes devices classified as static, mechanized and automatic. r e define static devices as equipment that passively depends upon the natural lovement of air currents to bring pollutants to the collector. Mechanized :ollection devices accumulate samples continuously or intermittently for 213 I subsequent laboratory analysis. Automatic devices are continuously operatiij sampler-analyzers that produce results directly in numerical or visual form.' 1 or both. For the purposes of this report we will only consider continuous automatic instruments as most of these instruments use the same basic chemical technique as utilized by the mechanized devices. Prior to discussing the status of aerometric technology, the objective!) of air quality monitoring require elaboration. Recently, Morgan and Ozolins^ 2 ' presented four major objectives which are summarized as follows: Documentation of Progress Toward Attainment of Air Quality Standards The mechanism of controlling air pollution is through emission regu- lations imposed upon individual sources. No certainty exists that the adoption and enforcement of a set of emission regulations will result in a sufficient reduction in emissions to attain the air quality standards. Air quality monitoring provides the only means of ascertaining that suffi- cient progress is being made to achieve the air quality goals within the desired time period. Thus the air quality monitoring stations should be sufficient in numbers and geographical distribution to provide represen- tative data for the entire region. In addition, where major point sources are likely to unduly affect a given area, it becomes necessary to locate monitoring stations which are primarily source-oriented. Determination of Air Quality in Nonurban Areas The primary emphasis in a program of emission control is to improve air quality in those areas where standards are not being met. Within most areas there are large areas of undeveloped land where ambient concentrations of most pollutants are well below levels specified in the standards. It is important that the quality of the air in these nonurban areas not be per- mitted to deteriorate to any significant degree. Of equal importance is the requirement to measure background concentrations of the air moving into a region. Thus some air sampling on the periphery (especially in the upwind direction) of the AQCR is necessary. Information on Air Quality During Episodes Control agencies are required to develop an action program to avoid the occurence of an air pollution episode. The heart of such a program is the emission-reduction plan. The enforcement of emission reductions must take into account the seriousness of the impending episode. Too little or too much of a reduction can result in a serious economic hardship upon the area. Therefore it is important to have immediate access to ambient concentrations data and follow a predetermined emission reduction plan consistent with the changing pattern of air quality. In order to provide the necessary data in "real time" to the control officer, most AQCR's will find it necessary to have at least one monitoring station equipped with continuous analyzers. Improvement in the Reliability of Diffusion Models Diffusion modeling has been found to be an effective tool in the management of air resources on a regional basis. Modeling can be used to 214 supplement air quality measurement data to provide a better indication of jzhe geographical distribution of air pollution. Additionally, and perhaps tiore importantly, modeling provides a means for evaluating the probable effectiveness of a set of control regulations prior to their actual adoption. With the present state-of-the-art of diffusion modeling it is necessary ;o verify model estimates against actual air quality measurement data. This diffusion model verification which is nothing more than fitting a linear regression model, requires air-monitoring data from a number of Locations within the area. The success of recent attempts to utilize these nodels has for the most part been a function of the amount of measurement lata available. Again, these activities have demonstrated the need for air quality monitoring throughout an area and not merely in one major munici- pality. Continuous Aerometric Monitors — Gaseous Pollutants Aerometric techniques in standard use today are based upon classical „ analytical techniques both chemical and physical. The following operational principles are commonly incorporated in continuous air monitoring instru- nentation for gaseous pollutants. Conductivity . The principle for conductometry , that is, electric con- ductance by soluble electrolytes, has had wide application as an analytical procedure. The electrical resistance of electrolytes in solution is inversely proportional to the conductivity, which in turn is proportional to the number of ions present and their mobilities. In dilute sample solutions, the measured conductivity can be directly related to the concen- tration of ionizable substance present. Sulfur dioxide has been measured 3y this procedure in continuous recording instrumentation for more than 15 ('ears. The basic concept involved absorption of sulfur dioxide in de-ionized \/ater (or a very dilute reagent) to produce an acid having conductance sufficient to be detected by a conductivity cell. Monitors employing de- Lonized water as the reagent result in the formation of sulfurous acid (H2SO3) . Interferences from carbon dioxide, salt, aerosols, acid mists and oasic gases are common. Most sulfur dioxide analyzers use distilled or 3e-ionized water reagent modified by the addition of hydrogen peroxide and a small amount of sulfuric acid. This modified reagent results in the formation of sulfuric acid (P^SO^) upon reaction with sulfur dioxide. The acidic property of this modified reagent reduces the solubility of carbon Jioxide gas within the reagent and minimizes this interference. Figure 1 displays, in schematic form, a conductivity-type analyzer. While instru- nents employing this principle have predominated the field in the past, instruments using either colorimetric or coulometric techniques have gained tfide acceptance in the past few years due to their specificity. Colorimetry . Colorimetry can be defined as a mode of analyses in which the quantity of a colored constituent is determined by .measuring the relative amount of absorption of light passing through a solution of the desired constituent. The constituent may itself be colored and thus be determined directly, or it can be reacted with a substance to form a colored compound and determined indirectly. Figure 2 is a block diagram of a typical colorimetric analyzer. As shown, an atmospheric sample is drawn into the air-reagent flow system, first entering the absorber or contactor where the desired constituent is reacted with the appropriate reagent. The air sample then passes to the 215 upper portion of the absorber where it is separated from the reacted reagenl then passes through a flowmeter where the rate is indicated and controlled, thence to the air pump and discharged to the atmosphere. The reacted reager passes from the bottom of the absorber into the continuous flow colorimeter where the optical absorbance of the solution is measured. In many cases a dual-flow colorimeter is employed whereby the absorbance of the unreacted reagent is initially measured. This measurement is used as a reference source. This principle is commonly employed for the continuous measurement of three air pollutants: sulfur dioxide, using the West-Gaeke technique or a modification; nitrogen oxides by the Saltzman method; and oxidants using the neutral KI procedure. Coulometry . Coulometry is a mode of quantitative analyses wherein the quantity of electrical current required to oxidize or reduce a desired constituent is measured. This measured quantity of current, expressed as coulombs, is proportional to the mass of the reacted material. Coulometric titration cells for the continuous measurement of sulfur dioxide, oxidants, and nitrogen dioxide have been developed as a result of this principle. One class of cells generally employed in continuous air monitoring are designed to respond to materials which are oxidized or reduced by halogens and/or halides as the case may be. Low concentration of the halogen and halide are maintained at equilibrium within the cell by means of competitive reactions at the cathode and anode. Upon introduction of a reactive material the halagen-halide equilibrium is shifted. The system is returned to its equilibrium conditions by means of a third electrode which regener- ates the depleted species. The current required for this generation is measured and is directly proportional to the concentration of the depleted species, which in turn is proportional to the quantity of desired consti- tuent. This mode of analyses can be classified as secondary coulometry usually employing a dynamic iodometric or bromimetric titration. These systems are designed to respond with a sensitivity in the lower part-per- billion range. Most commercial coulometric systems are made specific by' the use of pre-f iltration and/or chromatographic techniques that retain interfering compounds and permit passage of the desired constituents. Another type of coulometric cell (Fig. 3) designed for ozone analyses, employs amperometric coulometry. Ozone is permitted to react with an iodide solution within the cell releasing iodine which depolarizes the cathode, thus permitting current flow which is proportional to the ozone concentration. By utilizing dynamic reagent and sample flows over the cathode and anode a continuous measurement is achieved. This type of coulometric monitor, like the first one described, is subject to inter- ferences. Materials which undergo oxidation will appear as negative inter- ferences; positive interferences with those which undergo reduction will be observed. In some cases such interferences can be overcome by the selection # of chemically treated filters which are placed in the coming air stream. Flame Photometry . Flame photometry is based on the measurement of the intensity of specific spectral lines resulting from quantum excitation and decay of elements by the heat of a flame. Volatile compounds are intro- duced into the flame by mixing them with the flammable gas or with the air supporting the flame. Non-volatile compounds are aspirated from a solution into the flame. The specific wave length of interest can be isolated by means of narrow band optical filters, diffraction gratings, or by means of 216 prism. The intensity of the specific wavelength can be quantified by ans of a simple photo-tube or photo-multiplier tube and related electronics. Recent development of flame photometric detectors (4,5) having a semi- ecific response to volatile phosphorous and sulfur compounds has led to eir use in continuous monitoring of gaseous sulfur compounds. This flame otometric device consists of a photo-multiplier tube viewing a region ove the flame through narrow band optical filters. When sulfur compounds e introduced into the hydrogen rich flame they produce strong luminescence tween 300 and 423 mu. A specificity ratio for sulfur to non-sulfur com- unds of approximately 20,000 to 1 is achieved with a narrow band optical Iter of 394 + 5 mu. The detector response is a straight line relation- ip between 5 ppb and about 0.9 ppm on a log-log scale for sulfur com- unds having a sulfur content in excess of 50% by weight. Positive inter- rences from other sulfur compounds are common while monitoring for SO2, nee the detector responds to all sulfur compounds. Discretion should be ed in interpolating data obtained from this detector located in areas ere other sulfur compounds exist. Separation of part-per-billion levels of SO2, f^S, cs ?> an< ^ CH SH has cently become feasible through the use of chromatographic techniques' ' . is mode of separation followed by flame photometric detection of the parated sulfur compounds has led to the development of a new type of semi- ntinuous monitor for sulfur containing gases which is specific and free om interferences. Flame Ionization . Instrumentation employing flame ionization detectors, iginally designed for gas chromatographic detection of organic compounds, s had wide application as a continuous monitor for hydrocarbons. The ame employed in this detector results from hydrogen gas combusted in air, th the subsequent formation of water vapor. The hydrogen is mixed with mple air which is introduced at a steady, controlled rate, before the two ses reach the burner tip. When an organic compound is present in the air ream, the flame produces ionized carbon atoms. These ions produce an ion ow between the flame and the collecting electrode suspended above the ame. This small current flow is amplified and measured. The response for drocarbon is linear and generally proportional to the weight percent of rbon present in the compound. Advantages inherent in this detector are that it is: free from inter- rences resulting from inorganic gases, has a rapid response time, and has low "noise background" level. Recent investigations involving automated gas chromatographic ('' sep- ation of the air sample into three fractions had led to the development semi-continuous monitors for CO, CH4, and total hydrocarbons. A gas romatographic column provides separation of CO and CH. while flushing 1 other gases. The CH4 is measured directly, while the CO fraction dergoes conversion to CH4 in a controlled-temperature reactor containing nickel catalyst and is subsequently measured by the flame ionization tector. The total hydrocarbon measurement is made directly without romatographic separation. Total hydrocarbons less CH. provides an index reactive hydrocarbons. Nondispersive Infrared Photometry . The infrared absorption charac- ristics of several gases and vapors make possible their detection and alysis in continuous analyzers. For this purpose nondispersive infrared otometry rather than dispersive infrared spectrophotometry is used, rbon monoxide as an air contaminant is uniquely suited to this method of 217 analysis, and its absorportion characteristics and typical concentrations make possible direct sampling without pressurization. A typical analyzer (Fig. 4) consists of a sampling system, an infrared source, sample and reference gas cells, detector, control unit and amplifier and recorder. The reference cell contains a non-infrared absorbing gas whil the sample cell is continuously flushed with the sample atmosphere. The detector consists of a two-compartment gas cell (both filled with carbon monoxide) separated by a diaphragm whose movement causes a change of elec- trical capacitance in an external circuit, and ultimately an amplified electrical signal which is suitable for input to a servo-type recorder. During analyzer operation an optical chopper alternately exposes the reference cell and the sample cell to the infrared source. At the frequency imposed by the chopper a constant amount of infrared energy passes through the reference cell to one compartment Of the detector cell while in varying amount of infrared energy, indirectly proportional to the carbon monoxide concentration in the sample cell, reaches the other detector-cell compart- ment. These unequal amounts of residual infrared energy reaching the two compartments of the detector cell are reflected by unequal transformation of infrared energy to heat and thence to mechanical energy in the form of detector gas expansion. This unequal expansion is the force which causes variation in detector-cell diaphragm movement and the resulting variation in the electrical signal described earlier. Continuous Aerometric Monitors — Particulate Pollutants The various approaches to particulate measurement include: high-volume and low-volume filtration sampling, measurement of individual particle density and optical characteristics, measurements of aerosol opacity and light scatter, and settling rates. Measurements of the allergenicity and infectivity of aerosols are also frequently made. However, this presen- tation will be limited to those devices in general use and considered to be continuous monitors. Suspended Particulates . The recommended instrument for sampling large volumes of air for suspended particulate matter is the high-volume sampler. This sampler consists of a specially housed vacuum motor to which is attache a filter holder or adapter. It is evaluated and described by Robson and Foster I**) # While this device is not truly a continuous-automatic instrument it is at present the only device that has received wide acceptance in the United States for the determination of total suspended particulates between 0.3 and 100 microns in size. The adapter may be of one of two types: a circular 4 in. -diameter filter holder or a larger 8 by 10 in. rectangular adapter. The former is normally used in industrial-hygiene studies and will not be considered in this report. The latter adapter consists of two parts: the coneshaped stainless steel filter-support screen and an open rectangular face plate of case iron with a sponge-rubber gasket. In sampling, a filter is placed between the filter-support screen and the gasket face plate. When the adapter is screwed onto the blower unit, a circular rubber gasket is used to make an airtight seal. Air drawn through the filter is measured with a "visa-float" flowmeter which must be calibrated. Samples are usually collected for about 24 hr., with a flowmeter reading at the beginning and end of each sampling period. The average rate of flow is then determined from a calibration chart for 218 iach instrument. If desired, this device may be modified for continuous flow measurement ind recording. The modification consists of an orifice meter assembly attached to the •xhaust end of a high-volume blower unit. A bellows-type pressure trans- lucer is connected to the differential pressure tap of the orifice meter, he pressure developed across the orifice is continuously recorded on a :ircular chart and is converted to corrected airflow by means of appro- bate calculations. The filter material is generally glass-fiber although inert plastic later ials are used in special samplings for certain metallic compounds, he filter with the collected particulate is routinely sent to the laboratory "or not only the determination of the total particulate loading but for iubsequent analysis by emission spectroscopy for the following metals: Cr, lu, Fe, Pb, Mn, Ni, Sn, Ti, Zn, Sb, Bi, Cd, Co, Mo, Y. In addition analysis or sulfates, nitrates, and polynuclear hydrocarbons may be performed. Soiling Particulates . The tape sampler measures the fine suspended ^articulates in the atmosphere. Air is drawn through a section of white ilter paper, measuring one inch in diameter, at a pre-set rate (normally .5 cubic foot per minute) for a specific period of time. Generally, either ine hour or two hour sampling periods have been used. The darkness of the pot on the tape is a function of the particulate matter in the air and onsists of particles filtered out of the air. At the end of the sampling ieriod, the tape advances automatically by means of a timing mechanism, lacing a clean section of filter tape at the sampling port. The collected pot is automatically positioned under a photoelectric reflectance or trans- lission head which evaluates the density of the spot by measuring the light eflected from or transmitted through the spot to the cell. The greater he amount of particulate matter filtered out of the air, the darker the pot and the smaller the amount of light reflected or transmitted. The uantity of air sampled is expressed as lineal feet and the final result eported in either of two units of measurement, the reflectance unit ensity (RUD) or the coefficient of haze (COH) , per 1000 lineal feet of ir. The COH unit can be defined as that quantity of particulate matter hich produces an optical density of 0.01 when measured by light trans- .ission at 400 mu. The transmission of a clean filter is used as a refer- nce and is set at 0.0 O.D. The RUD is the percentage reflectance obtained fter passing 1000 lineal feet of air through a filter paper. The reflec- ance of a clean filter paper is set at 100% on the reflectance meter and .s used as a reference. Nephe lome try . A common effect of particulate air pollution is the eduction of visibility. Small particles suspended in the air scatter ight out of the line of vision, making distant objects appear less distinct, 'isibility can be defined as that distance at which the difference in :ontrast between the background and the object being observed is too small o perceive. Suspended particulates in the size range of 0.2 to 0.8 microns scatter ays of light in all directions. The amount of light scattered in any one tirection depends on the size, quantity and composition of the particles, herefore, to measure the amount of light lost by scattering, it is necessary :o measure the scattering of all angles' 10 '. The air sample is drawn into the detection chamber where it is illumi- lated by a pulsed-flash lamp. The scattered light is measured over all 219 scattering angles by means of mirrors and photo-multiplier tubes. The signal produced by the photo-multiplier is averaged and compared with a reference voltage from another phototube looking at the flash lamp. Calibration is performed by introducing clean filtered air and Freon-12 as reference sources. This device is designed to provide a reading of light scattering which can be defined as the reciprocal of the distance in which 63% of the light is lost from the source. The amount of light scattering is proportional to the mass concentration (ug/m 3 ) of suspended particulates if the mass and size distribution of the particles is assumed constant. Measurements of suspended particulates with' this device affords the user a "real-time" continuous measurement. Piezo - e lee trie Sensor . This relatively new device delivers "real- time" measurements over a particle size range from 0.01 — 15.0 microns at concentrations up to 100,000 ug/m 3 . It is quite versatile, applicable to monitoring the ambient atmosphere, stack effluents, and motor vehicle emissions. The air to be tested is drawn through the unit by a small accessory vacuum pump. As the gas enters a teflon chamber, particles are electro- statically charged. The flow is directed over a piezo-electric sensor (S^) and an electric field forces all of the particles into contact with the sensor. The adhering particles lower the resonant frequency of the sensor in direct proportion to their mass. A second piezo-electric sensor (S2) mounted in the chamber is connected in a bridge circuit with S^. It is not electrostatically charged, so particles do not adhere to it. It serves as a reference for S]_, that is, it is exposed to the same influences (temper- ature, pressure, etc.) as S-,, so any change in the relationship between the frequencies of the sensors will be caused only by particles accumulated on St . The output signal of the device is generated by mixing the fre- quencies of S-^ and S2 so that the measuring sensor frequency is subtracted from the reference sensor frequency. The rate of change of this output frequency is directly proportional to the mass concentration of the particl Mass concentration equals the change in frequency during a given period of time divided by a sensitivity constant. The instrument can be connected to a digital frequency counter display, a timer, and a printer, and its output can be transmitted from a remote station to a central location. The Beta absorption tape monitor has also recently been used in the measurement of total suspended particulate. This monitor uses Beta radiati< attenuation for the measurement technique. A sample of the particulate is deposited on a paper filter tape for a present period of time. The tape spot is then exposed to a stream of Beta particles from a small radioactive source. The Beta particles interact with the sample's electrons and the decrease in the Beta particle count as sensed by the detector is directly proportional to the number of electrons present in the sample. Thus the technique measures a parameter which is directly proportional to mass. Current Developments in Continuous Aerometric Monitors The most promising instrumentation developments for the measurement of air pollutants are based upon the application of well known spectroscopic quantitative-analytical methods in new configurations and combinations. All of these developments have the two main purposes: (a) the increase of instrument sensitivity in order to obtain sufficiently large signal-to- noise ratios for reliable and sufficiently accurate measurements of the 220 lommonly low air pollutant concentrations, and (b) the achievement of good .nterferences with the measurement of a particular pollutant species by ther atmospheric or pollutant species and compounds. The physical methods vailable and the instrumental details required toward these aims have been xhaustively discussed and referenced in a recent NASA Report by Ludwig' 1( ^) ; herefore, here only a brief description of the basic principles involved rill be given, together with representative and primising developments which ire relevant for continuous and/or remote measurements of gaseous air jollutants. These developments can be subdivided into two major areas which leal with the application of spectroscopic and interferometric devices on he one hand and with the adaption of laser techniques on the other. Spectroscopy . The main drawback of conventional spectroscopy — low ensitivity and low selectivity — can be overcome in principle by a method :alled correlation spectrometry. The basic concept utilized is the well- nown technique of conventional quantitative spectroscopy of gas mixtures, 'or developmental applications several modifications of this principal iave been considered in which either the spectrum is moved periodically cross the exit slit array or vice versa, and in which the resulting lternating light signal is collected on a photodetector and processed lectronically . Recently, a commercial instrument (Barringer Research, .td.) has become available. In this instrument, instead of an exit lit-array, a correlation mask is used which, for a portion of a pectral band of the gaseous species to be monitored, matches the spectral eatures both with respect to the wavelength and the relative intensity listrubitions of the lines (wavelength and intensity correlation) \H> . For aerial air quality assessments, for example, the instrument can be tounted in a vertically downward looking configuration in an aircraft and onitors sunlight reflected and scattered from the pollutant in the air ayers underneath. The monitored species content in the atmosphere is .etermined in terms of an integrated optical depth in ppm-m (concentration imes height of the line-of-sight in units of parts per million times meters) nd, for example, can be converted to an average concentration by assuming i uniform species concentration over the height of the inversion layer, he calibration of the instrument is this application depends strongly on he local elevation of the sun and, in particular, by the local and temporal cattering properties of the atmosphere which is affected by the presence if aerosols and their distribution in the air-layers monitored. Thus far inly NOp and S0 2 have been monitored successfully in spectral regions where legligible interferences by other gaseous pollutants occur, and the adaption >f the instrument for field measurements of the pollutant species NO, CO, £>2, and O3 is still in the development stages. Therefore, further research is required in the area of medium-to ligh-resolution spectroscopy of gaseous air pollutants and in the area of .ight scattering and absorption by aerosols in narrow and/or limited spec- ial regions which are of interest to correlation spectroscopy? at the same :ime, further development and test work is needed on instrument designs rtiich would allow the simultaneous remote measurement of several pollutants ilso in cases where partial or complete overlapping of spectral bands occurs. Laser Developments . The extensive application of absorption spectro- scopy to pollutant analysis in the past has been limited by the degree of .ight-beam collimation and the amount of light energy available from ordinary .ight sources for medium- and long-path measurements through the atmosphere. 221 Hence, any development of light sources which will alleviate the problems of beam divergence and will increase the radiation energy available in spectral intervals where pollutants are strong absorbers, will allow signi- ficant improvement of pollutant measurement techniques. The most important new development in light sources is the laser (short for light amplification' by stimulated emission of radiation) which inherently can provide light beams of very small beam divergence and high spectral intensity. Typical optical arrangements for both laboratory and atmospheric transmission applications are shown schematically in Figure 5. It should be noted that for atmospheric transmission measurements, the collimation of laser beams is limited primarily by the diffraction effects of the optica! system used and by the beam-spreading effects of atmospheric scattering and turbulence. Although at the present time no satisfactory experimental data are available about the propagation characteristics of narrow and wide cross- section laser beams as a function of the beam-interfering atmospheric structure, content and motion, it seems reasonable to expect that atmospheric beam spreading will not seriously limit the application of low power and continuous laser sources to remote pollution measurements by aerial, medium- and long-distance methods. At the present time a multitude of gas lasers are commercially avail- able and more are in various development stages. They can emit at several or many wavelengths in the near ultra-violet, and visible and the infrared regions of the spectrum by stimulated emission of gases like neon (Ne) , argon (Ar) , iodine (I~) , carbon dioxide (CO ) , carbon monoxide (CO) , nitric oxide (NO) , nitrous oxide (^0) and others. Furthermore, various successful techniques have been introduced by which the wavelengths for peak power emission of multi-line gas lasers can be changed or shifted. For example, refracting prisms and diffraction gratings have been introduced into the optical cavities of noble gas and nitrogen as well as carbon dioxide lasers and are becoming commercially available standard accessories. Recently a new method for the wavelength-shifting has been developed for the carbon dioxide and the recently discovered iodine laser; in a separate compartment of the optical cavity a special gas sample is intro- duced by which the laser output energy as a function of wavelength is changed from different pressures of the gas sample. (See Fig. 6) . In particular, it has been shown at C0 2 ~lasers and l2~lasers can be made speci- fic by this method and by the introduction of isotopic laser gases for five major pollutants: ethylene, ozone, carbon monoxide, nitric oxide and sulfur dioxide. In addition to these five pollutants, many others can be detected in principle by the absorption of laser radiation, and the sensitivity for practical measurements will depend on the strength of the useful pollutant absorption lines, the intensities of the useful laser lines, the stability of the laser output energy, the beam fluctuations caused by atmospheric turbulence and the refinements built into the electronics of the detector system. Representative estimated sensitivities for infrared measurements of some gaseous pollutants by different gas lasers are shown in Table II. The rapid evolving new physical methods of correlation and laser spec- troscopy for the remote and the local monitoring of air pollutants by their very nature possess inherently the very promising potential for instrumental simplicity, good durability and reliability, high sensitivity, easy adapt- ability to automation and electronic interfacing, and excellent mobility when compared with the presently common techniques employed by local 222 onitoring stations. Although their application to measurements in the Leld is still in its infancy, it appears eminently reasonable to expect iat these methods can be developed to a practical degree of perfection lich will make them superior to any other procedures for accurate and wide- oread air quality monitoring. Accurate, specific and flexible-monitoring techniques for large areas E population, industry and farmlands, as well as for particular local pplications, are mandatory for both the realistic and rational control of ir pollutants and the realistic and rational setting of sound air quality tandards. The superiority of these over other methods is further ampli- ied by the fact that they can be adapted easily to a vast amount of ifferent pollutant species while leaving unchanged the basic instrumentation rinciples and concepts. Hence, one can envision the emergence of new streamlined" and standardized pollutant-monitoring systems for large areas, he systems would be based upon a relatively small number of similar or ven equal basic instruments with relatively cheap interchangeable access- ries. These could be used in stationary or mobile modes of operation for he measurement of many more air pollutants than is possible at the present , ime by the vast variety of individual monitoring instruments which are ommercially available for the measurement of a relatively small number of ollutants. For example, the price of 100 new and fully automatized air nalyzers for the measurement of five gaseous pollutants by presently common echniques is about $2.5 million and requires an additional amount of at east about $250 thousand per year for operating costs. These figures do ot include salaries of highly qualified and diversified technicians and taff members. Thus an equal number of correlation spectrometers for local nd remote, short- and medium-distance measurements of two or three gaseous ollutants would cost about $1.2 million to $1.5 million and would presumably equire a much lower yearly operating budget. Similar or much lower price anges may be anticipated in the not too distant future for local, short- nd medium-distance analyzers which operate on the basis of frequency shifted, ow-power CO2- and n^-lasers. Low-power, interchangeable helium-neon laser ubes are advertised now for less than $50. tationary Source Measurements Stationary source emissions monitoring has been virtually ignored until he past several years. With the passage of the Clean Air Act Amendments f 1970 new emphasis has been placed on the development of such instrumen- ation. The Act requires the establishment of performance standards for tationary sources and the monitoring of stationary source emissions. The monitoring of particulate emissions in the past has been attempted hrough the use of transmissiometers or smoke density meter and tape samplers hich exposed a white paper surface to the effluent and measured the decrease n light reflectivity. The major problem with both techniques is that they easure a change in light intensity. Unfortunately, this intensity change s affected by particulate size, number, shape, color, index of refraction, hemical composition and in some cases deposition characteristics. Numerous attempts have been made to produce transmissometers which ill accurately reflect the mass of particles. The "best" correlation ound thus far is a unit which was shown to be in error by no more than 200 ercent under typical conditions. The techniques which appear to be viable at this time are Beta absorp- 223 tion with semi-continuous paper-tape sampling and a piezoelectric quartz crystal microbalance with electrostatic precipitation or cyclone collectors. The Beta radiation attenuation technique uses an extracted sample whicl is deposited on a paper filter tape for a preset period of time. The tape is indexed into a stream of Beta particles from a small radioactive source. As some of the Beta particles interact with the sample's electrons, the decrease in the Beta particle count as sensed by the detector is directly proportional to the number of electrons present in the sample. Therefore, the technique measures a parameter which is directly proportional to mass. Hence the identification of this technique as a potential usable mass monitor. Problems to be overcome are to produce a higher counting rate and therefore a more real-time monitor and improvement in reproducibility. The application of the piezoelectric quartz microbalance is relatively recent. The basic principle uses the piezoelectric effect to make a small quartz crystal vibrate in a horizontal plane. The frequency of this vibrati is very constant and is determined mainly by the size or mass of the crystal and to a lesser extent by the temperature. The temperature effects can be minimized and compensated by the use of an identical crystal in a bridge circuit. The particles are deposited on the sample crystal by electro- static precipitation, cyclone, impactor, etc., for a period of time. The increased mass of the crystal plus particles lowers the natural vibration frequency. This change in frequency is directly proportional to the mass of particles on the crystal. The sampling and analysis times are variable depending on the amount of particulate matter being sampled, and the accurac desired. High accuracy may require a longer frequency counting period. Vei low particulate loadings require longer sampling periods to collect a measurable amount of particulate. A typical monitor sampling at 1 liter/ minute at 0.0 5 gr/SCF can collect enough matter for analysis in under 1 second. Potential problems in this device at this time are concerned with larger particles not remaining firmly seated on the crystal during each vibration, problems encountered in precipitating the particles onto the crystal, and problems of cleaning the crystal after the measurement. One manufacturer uses a light adhesive coating to make larger particles adhere to the crystal better but this will probably necessitate more frequent cleaning. The usual electrostatic precipitation problems can be countered by the use of impactors or cyclones but at the sacrifice in ability to measure the smaller particles. The PQ device has not been extensively tested in a stack environment at this time. The emission monitoring for sulfur dioxide is somewhat advanced over that of particulates. The continuous monitoring for sulfur dioxide has been accomplished using ultraviolet detection principles. There is present] available on the commercial market an instrument which has operated satis- factorily for over a year on a large coal-fired boiler. In addition, such monitors have been used to measure sulfur dioxide emissions from sulfuric acid plants. In both instances there were some initial problems to overcome with sampling systems and sample pretreatment. However, these difficulties have been solved and the units are reportedly operating satisfactorily. Other measurement techniques have been employed such as the galvanic or fuel cell and electroanalytic methods. Preliminary reports on the fuel cell device indicate that there are problems still to be resolved with this technique such as a short-life time (30 days) for the sensing element and random drifting of the unit. 224 Instruments utilizing the non-dispersive infrared principle have been and are being used to some extent. The major problem with this procedure is that the stack gas sample must be conditioned to remove water vapor (100 ppm H~0 vapor = 1 ppm SO2) . Such conditioning also removes approxi- mately 5 percent of the sulfur dioxide in the sample stream. This problem has been partially overcome by the close control of the condensation temperature. Monitoring of oxides of nitrogen has been accomplished by the use of ultraviolet instrumentation. Since nitric oxide is essentially transparent in the visible and ultraviolet, quantitative conversion to nitrogen dioxide is required for measurement by the instrument. This conversion is achieved by reacting the sample containing nitric oxide with oxygen at elevated pressure. The reaction is both rapid and reproducible. Normal operation allows for the instrument to scan the incoming gas stream for its nitrogen dioxide content. The time interval for this scan is 1 to 3 minutes. The incoming gas stream is then contained in the sample cell and pressured to approximately 5 atmospheres with oxygen. The nitric oxide is thereby oxidized to nitrogen dioxide and a reading made. Time sequence for this * operation is usually. 5 to 7 minutes. By this alternate operational mode the gas stream concentrations of both nitric oxide and nitrogen dioxide are obtained. This instrumental technique has been used in the monitoring of nitric acid plant effluents as well as combustion sources. Galvanic or fuel cell technology has also been used for the monitoring of oxides of nitrogen in stack gases. Presently there are other chemical and physical techniques being utilized to monitor diverse pollutants from stationary sources. Among these one should include gas chromotography followed by electrometric titration or microcoulometric detection for the measurement of hydrogen sulfide, sulfur dioxide and various organic sulfur compounds from various sources within Kraft pulp mills. The fluoride-specific ion electrode has been reported to have been used to monitor fluorides in stack gases. Mobile Source Measurements The measurement of pollutants from motor vehicles has centered around three pollutants: hydrocarbon, carbon monoxide and oxides of nitrogen. As these pollutants vary in both concentration and rate of flow as a function of engine speed and load, monitoring instrumentation or sample collection methods have had to be designed to meet these circumstances. In the past, in order to determine the true mass emissions from a motor vehicle, it has been operated on a dynamometer using a driving cycle which simulated actual road use. The instrumentation used to follow this sequence of events has been connected directly to the exhaust pipe of the vehicle and therefore a short-time response was required to monitor the rapidly changing concentrations. Non-dispersive infrared instruments were utilized to determine the carbon monoxide and hydrocarbon concentrations. The hydrocarbon analyzer was sensitized with n-hexane. Hence the analyzer responded more strongly to paraffinic hydrocarbons, less to olefinic and least to aromatic and therefore was strongly dependent upon fuel composition. Under new Federal standards and regulations promulgated for 1972 model year vehicles, the measurement of hydrocarbon emissions will be accomplished using the flame ionization detection technique. In addition, the driving 225 cycle has been changed to more truly represent driving patterns in major metropolitan areas and the exhaust gases are collected in a large plastic bag after dilution with air. Carbon monoxide is still measured by the non- dispersive infrared method. The flame ionization method gives a more accurate measurement of the hydrocarbon emissions as it will detect any organic molecule that has a carbon-carbon or carbon-hydrogen bond. It is therefore not as fuel sensi- tive as the infrared method. Recently Federal motor vehicle standards have been proposed for nitro- gen oxides. The proposed method of measurement utilizes the chemilumines- cence technique. Basically the instrument operates on the principle that nitric oxide reacts with ozone to give nitrogen dioxide and oxygen. Approximately 10 percent of the nitrogen dioxide is electronically excited to higher energy levels. The transition of excited nitrogen dioxide to the ground state yields a detectable light emission at low pressure. The inten- sity of this emission is proportional to the mass flow rate of nitric oxide into the reactor. The light emission can be measured utilizing a photo- multiplier tube and associated electronics. As the standard is for nitrogen oxides, any nitrogen dioxide present in the exhaust gas must be converted to nitric oxide. This is accomplished by utilizing a nitrogen dioxide converter which is connected into the inlet gas stream. The conversion is accomplished by thermal decomposition of nitrogen dioxide to nitric oxide and oxygen. Substances which cause positive interferences with this method are ammo- nia, low molecular weight amines, nitrates nitrites, nitriles and nitro compoun Fuel cell technology has also been used in instrumentation for nitro- gen oxides measurements. It is reported that such devices have proved to be reliable in service. Interferences from side-chain aromatic compounds have also been cited. A comprehensive bibliography of recent papers, extending over the entire field of pollutant measurement activities, is issued biannually in the publication Analytical Chemistry . The reader is referred to the most recent publication in April, 1971. References 1. "1969 Inventory of Air Pollution Monitoring Equipment Operated by State and Local Agencies," Publication No. APTD 0588, U. S. Environ- mental Protection Agency, Air Pollution Control Office, Research Triangle Park, North Carolina, March 1971. 2. Morgan, G. B., and G. Ozolins, "Air Quality Surveillance." Presented at the 11th Methods Conference in Air Pollution Industrial Hygiene Studies, University of California, Berkeley, California. March 30- April 1, 1970. 3. Bryan, R. J. "Air Quality Monitoring," in Air Pollution Vol. II, A. C. Stern, Ed. Academic Press, New York, N.Y., 1968. 4. Crider, W. L. Analytical Chemistry , Vol. 37, p. 1770 (1965). 226 5. Brody, S. S., and J. E. Chaney. J. Gas Chromatography , Vol. V, p. 4 2 (1966) . 6. Stevens, R. K. , A. E. O'Keefe, J. D. Mulik, and K. J. Krost. "Gas Chromatography of Reactive Sulfur Compounds in Air at the ppb Level." Presented at the 157th Nat. A. C. S. Meeting, Minneapolis, Minnesota (1969) . 7. Stevens, R. K., A. E. O'Keefe, and G. C. Ortman, "An Automated Gas Chromatographic Procedure to Measure Atmospheric Concentrations of Carbon Monoxide and Methane." Presented at the 11th Methods Con- ference in Air Pollution Industrial Hygiene Studies, University of California, Berkeley, California. March 30-April 1, 1970. 8. Robson, C. D. , and K. E. Foster. "Evaluation of Air Sampling Equip- ment." Presented at the Annual Meeting of the American Industrial Hygiene Association, Detroit, Michigan (1961) . 9. Charlson, R. J., N. C. Ahlquist, H. Selvidge, and P. B. MacCready, Jr. "Monitoring of Atmospheric Aerosol Parameters with the Inte- grating Nephelometer. " APCA Journal, Vol. 19, No. 12. December 1969. .0. Ludwig, C. B., R. Bartle, and M. Griggs, "Study of Air Pollution Detection by Remote Sensors," Report GDC-DBE68-011 ; December 1968, NASA Scientific and Technical Information Facility, P. 0. Box 33, College Park, Maryland 20740. .1. Barringer, A. R., Newberry, B. C, "Remote Sensing Correlation Spec- trometry for Pollution Measurements," 9th Conference in Air Pollution and Industrial Hygiene Studies, Pasadena, California, February, 1968. 227 Table I Estimated Number of Air Surveillance Devices in Routine Operation in the United States ' ' (June, 1970) Pollutant and method Nonfederal APCO Total agencies Static Gases: sulfation rate 2,933 214 3 ,147 Particulates : Settleable (dustfall) 3,220 3 ,220 Windblown (sticky paper) 897 Mechanized 897 Gases : Aldehydes 271 271 Ammonia 262 262 Nitrogen dioxide 362 200 562 Oxidants 395 395 Mercury 50 50 Sulfur dioxide 515 200 715 Hydrogen sulfide 153 153 Particulates : Suspended (Hi-Vol) 2,074 293 2 ,367 Membrane filter 55 55 Cascade-fractional 15 15 Soiling (spot tape) 461 Automatic 10 471 Gases : Aldehyde 16 16 Carbon monoxide 218 10 228 Carbon dioxide 10 10 Hydrogen sulfide 83 83 Nitric oxide 117 17 134 Nitrogen dioxide 189 17 206 Oxidants 122 14 136 Sulfur dioxide 235 44 279 Particulates : Soiling (automatic tape) 367 7 374 Total 12,900 1,146 14 ,04 6 228 Table II Representative Details for the Detection of Some Pollutants by Laser Radiation in the Infrared \±Q) Pollutant Source Location or ir band centers (u> Laser line to be used Concen- tration in parts per million to give 5% signal change over a 1 km path (estimated) Remarks Marsh gas 3.35, 7.7 He-Ne-3.39 0.03 Naturally in the air. '2*2 Auto ex- haust com- bustion 13.7 Ne? Very strong absorption. '2 H 4 Auto ex- haust com- bustion 10.52 CO -5-10. 53 0.02 Distinctive spec- trum, strong Q- branch. Many, in- cluding auto exhaust 3.4 12-3.43 0.05 C-H band is a measure of total organics. Atmos- pheric photo- chemis- try 5.4, 7.8 He-Ne? 0.05 Other bands are available. Auto ex- haust com- bustion 5.3 I 2 -5.5 0.5 Iodine line will penetrate humid atmosphere. Auto ex- haust com- bustion 3.4, 6.2 Rare gas? A difficult case due to water interference . Auto ex- haust com- bustion 4.7 I 2 -4.86 2.0 Some other laser line could make detection more sensitive. Atmospheric photo- chemistry 9.6 COo-9.5 0.05 One of the simplest cases. 229 Table II (continued) Representative Details for the Detection of Some Pollutants by Laser Radiation in the Inf rared HO) Concen- tration in parts per million to Location give 5% of signal change ir band over a 1 km centers Laser line path Pollutant Source V to be used (estimated) Remarks so 2 Burning of sulf ur- cont . 7.3, 8.7, Needs work to find fuels 18.5 Ne-7.4 0.03 better laser line. NH 3 Organic wastes, Very strong lines at about 10 . 3 and industry 10.5 CO 2 -10.7 0.02 10.7. 1 H 2 S Industry 2.6, 7.7 Kr? HF Burning of plastics 2.3 Kr? HC^ Burning of plastics 3.6 Xe? D 2 Atomic energy install- | i ations 3.7 Xe I 230 CABUATV uquo MfTHMO TUM L_ ~ J TEMPERATURE-CONTROLLED CABINET Figure 1: Schematic Diagram of a Conductivity-Type Monitor (3) K1AL KX.UTIOH ITO»AQt Figure 2: Schematic Diagram of a Color imetric-Type Monitor (3! 231 3 J < 3 o cc D O CO or < a: Oo0 OoOo»o0 Oo » 0^ J ■■■■■■■■ ■■ ■> ■ • ■ 1133 31dVWS )■■■■ ■■■■■■■■■■ ■ 1133 33N3H3J3U > o or < cr C/1 UJ CE cr> o cu > •iH M M CU U) •H TD C — M S rd M rd CJ ■H •P id e cu CJ CO cu M d en ■H fa P O P •H c o £ CU a >i Eh TJ Oi M (0 M m C H 1 1 o c 2 < SMALL ANNULUS WIRE CATHODE ^ ELECTRODE SUPPORT PLASTIC BODY WIRE ANODE AIR DISCHARGE < \ \\ \\r- | 1 ^ \ \ \ X \ 1_ 1 \ \ \ \ ; J=< iiiiiiiiiiiiiiiiiiiimiMiiiiiiih- - T— i i I 3 | 1 1 z < "iT or UJ O UJ >- Q£ UJ _ - '1 1 1 o O CJ ■M U P a: p. en 0, UJ rd >1 I/O •H H or Q I z o U ■H P t— +J (I) id £ o e on r-l UJ xs 13 t— u <. w u < u en ■H fa 232 a. DETECTION SYSTEM LASER AIR IN MULTIPLE PASS CELL DETECTION SYSTEM I SMALL RECEIVING TELESCOPE LASER -AIMING TELESCOPE RETROFLECTOR POLLUTED AIR ^ Figure 5: Typical Optical Arrangements for Pollutant Absorption Measurements by Lasers: a. Folded Laser Beam, b. Retroref lected Laser Beam PULSING GAS WAVELENGTH SELECTION ARTMENT GAS COMPARTMENT jg^,^/ FLAT MIRROR SPHERICAL GROUND GLASS JOINT, OUTPUT GAS MIRROR RESERVOIR Figure 6: Laser Light Source for Specific Pollutant Detection 233 THE EFFORT FOR CLEAN AIR IN THE NETHERLANDS By N.J. A. Groen Chief Public Health Officer State Inspectorate for Public Health Leidschendam, The Netherlands It is said that the late King Edward I, who was reigning over England at the end of the thirteenth century, received a formal complaint concern- ing air pollution. The complaint was forwarded by a number of noblemen, accusing their subjects of using coal fires which caused smoke and soot and defaced their properties. Although the King died in 1308, we— as fighters for clean air-- consid- er him as immortal because, one year before his death, he issued the first decree against air pollution; in fact a decree against the use of coal as a fuel in London. There were successive sanctions in his decree: first of all a fine and, for recidivists, destroying of their furnaces. Although it may not have been in these particular sanctions, it is well known that in the same era a man was tortured in public because the smoke from the chim- ney of his house heavily contaiminated the environment. Since John Evelyn, walking in the Royal Place at Whitehall in 1665, described a tremendous smoke invading the Court, we can conclude that things seem not to have improved much during the succeeding four centuries. Evelyn suggested a quite modern solution: the creation of green spaces and a better town planning. However he was ahead of his time; it took a couple of centuries more before the Clean Air Act came into force in the United Kingdom. Air pollution in that period was not restricted to England. In The Netherlands, the City of Haarlem issued a decree in 1608, prohibiting the use of English and Scottish coal by breweries because of the smoke coming from this kind of fuel. The issue of this decree possibly had a political background since the bleachers in the town polluted the water that the brew- eries needed for preparing beer, and for that reason, some years before, bleaching had been prohibited in certain areas. Although the complaints of the brewers and the revenge of the bleachers perhaps didn't result from pure reason, they lead to an improvement of the water and air situation in that region. In this respect we must confess that this kind of reasoning has been for too long a leading principle in the battle against environmental pollu- tion. On the other hand we must be aware that success in this battle is closely connected with progress in science, and the availability of better means for pollution prevention. This holds, as far as I can see, for the whole world and for Holland as well. General The Netherlands is a relatively small, but very densely populated country, especially in the western part. The population is still growing. More than 55% of the population lives in the big cities; only 22% lives in 234 small villages. The concentration of industry in some areas has grown con- siderably, especially since the second World War. Rotterdam is considered to be the biggest port of the world, with a turnover of more than 160 million tons per year. Near Rotterdam are five big oil refineries with a total capacity of 62 million tons per year. The Netherlands is a flat country without important mountains or val- leys. Our highest hill, at the point where Germany, Belgium and Holland meet, reaches 321 meters. The climate is a moderate sea climate. Wind is, on the average, rather strong and variable. Near the coast, where most of industry is situated, it is stronger than near the eastern border. However there are periods of several days with very low wind velocities and espe- cially in wintertime, with fog. Sources of Air Pollution The oldest source of man-made air pollution is the use of fuels for heating. Before the second World War the fuel normally used for domestic heating was, in contrast with some other countries, a good quality of an- thracite or coke, burned in closed furnaces. The use of open fires or bituminous coal was rare. After the war the use of oil and kerosene emerged as a more convenient and cleaner way of heating. However, during the last five years the use of natural gas, found in this country in enor- mous quantity and almost without sulphur, has increased very rapidly for domestic heating. The government's aim is to completely change to natural gas for domestic heating in our cities in a period of approximately five years. In presenting a new law against air pollution to the parliament in September 1968, the government noted that the increasing availability of natural gas gave reason to expect a decrease of that part of the nation's air pollution caused by domestic heating. Since that time the concentra- tion of sulphur dioxide in our cities has, in fact, shown a decrease, and it may be expected that this decrease will continue. There are, in certain areas, e.g. in the area between Rotterdam and The Hague, an important number of glasshouses for growing fruits and vege- tables, which have been, until now, mainly heated by high sulphur content fuel oil. With significant financial aid from the government and other official institutes, the way is being cleared to use natural gas instead of oil for this purpose. It is expected that within three years the majority of glasshouses will be heated by gas. This change will undoubtedly lead to an important decrease of sulphur dioxide concentration in cities like The Hague, Delft and Rotterdam. Industry and power plants are still using coal, as well as natural gas and oil. Here, too, there is an increasing use of gas. It is estimated that in 1970, the total national energy supply was 11% by solid fuel, 65% by liquid fuel and 24% by gas. The availability of natural gas has caused another improvement. Gas- works, present in most larger cities, with their dust and bad odors have completely disappeared. Transportation is the second and newer cause of air pollution in Hol- land. Our railways exclusively use electric or diesel electric drive, causing almost no air pollution. However the number of motor cars is in- creasing rapidly. It now amounts to nearly 3 million and by 1975, that number will rise to 5 million. Though we can be proud of ouj? — single — motorcar industry, it is clear that we are not in a position to make 235 regulations for cars from other countries. Therefore restrictions for new cars are worked out jointly with other European countries; and will be put in force before the end of this year. The maximum carbon monoxide content during idling will be fixed at 4.5%; and the total amount of carbon monox- ide and hydrocarbons, emitted during a European driving cycle, will be re- stricted. Industry is the third source of air pollution in our country and is developing very rapidly. The chemical and petrochemical industry espe- cially is increasing, not only in size but also in diversity. Every indus- try needs a license before coming into operation. This license, until now given by municipal authorities, is granted under certain conditions. Lack of staff in most of our municipaities during past years has underlined the necessity for better supervision by central governmental authorities. Work- ing along these lines, it has been possible to restrict air pollution caused by new industries. Our new law, accepted by Parliament during the past year,! and probably coming into force this year, will improve control of industrial air pollution. Aspects of Air Pollution As measured by the usual parameters and expressed as sulphur dioxide and smoke, air pollution in The Netherlands is relatively moderate. Smoke concentrations are far below those in the United Kingdom, measured by the same method. Average sulphur dioxide concentrations during the winter months in Rotterdam are below 300/ug SC^/m . These concentrations are still decreas ing , but occasionally rather high concentrations occur, and there have been 14 days with an average concentration of 500 /ug/SC^/m 3 or more during the winter of 1966/67. The concentrations of polynuclear hydrocarbons are very small, much lower than those found in other European countries: the average concentration of 3 .4. -benzpyrene in Rotterdam in the winter of 1967 was only 5/ug/1000 m 3 . Adverse effects of air pollution on plants and vegetation are frequently observed, but normally are restricted to a small area. Damage by sulphur dioxide, hydrogen fluoride, photochemical smog, ethylene and nitrogen oxides, have been observed. A number of investingat ions in this field have been carried out the Institute for Plant-Disease Research (Instituut voor Plan- tenzicktekundig Onderzoek, "IPO-TNO") at Wageningen. Special investigations concerning the influence of air pollution on health have not given significant results. A careful study by Dr. K. Bier- steker on health effects during a period of heavy air pollution in December 1962 in Rotterdam indicated a small increase in mortality, but this increase was not significant, and its relation with air pollution could not be proven. Another investigation, comparing health conditions of school children in a polluted and a non-polluted part of Rotterdam, gave results indicating dif- ferences, probably more due to different social conditions than to air pol- lution. An important investigation, concerning the incidence of chronic non-specific respiratory diseases in a polluted and a non-polluted part of the dountry, did not show any significant influence of air pollution. The polluted region chosen was the town of Vlaardingen, in the Rotterdam area. The non-polluted area chosen was a village (Vlagtwedde) and a small town (Meppel) , both in the northeast of the country. Nevertheless we have had periods of increased air pollution that have caused much public concern. Some of these periods were clearly due to 236 iccidents in industry; others by a combination of high emission from one or nore industries and unfavorable meteorological conditions. For the evalua- :ion of such situations — and for normal situations as well — we receive in- lispensable help from the Royal Netherlands Meteriological Institute (Konin- clijk Nederlands Meteorologisch Instituut — KNMI) at De Bildt, near Utrecht. There is increasing public concern about air pollution in our country md a fear of the influence of air and water pollution on health. The num- ber of complaints about bad odors or other observable effects of air pollu- :ion is increasing. This does not prove that malodors occur more frequently ;han some years ago, but the population is more aware of these unpleasant situations and no longer accepts situations that would have been accepted 10 or 15 years ago without complaint. This attitude may be helpful for those that have to control air pollu- tion, but it is not without certain disadvantages. It may hamper a well balanced policy that on a long term basis will give best results. yaw Against Air Pollution As already noted, a special act against air pollution has been accepted )y the Parliament and is now partly in force. As the result of this law the government is authorized to promulgate regulations to control air pollution ;:aused by apparatuses, fuels or other activities. Among the apparatuses that ran be regulated are large and small installations in industry, motor vehi- :les, furnaces for domestic heating, airplanes and domestic chimneys. One of the first regulations applicable to apparatus will probably be :he obligation to have new types of motor vehicles tested. Possibilities in ;he fuel sector are the prohibition of the use of certain fuels, for instance ;hose with a high sulphur content, perhaps limted to more polluted areas in :he country. On the other hand we can envision limitation on the composition )f fuel for motor vehicles. However, for the time being, we are not yet ready to do all these things and must wait for the future to learn how to Implement this new act. The Inspectorate of Environmental Hygiene was established in 1962 as an Independent part of the organization (under the Minister for Social Affairs and Public Health) charged with the supervision on public health (Staatstoe- 2icht op de Volksgezondheid) . This inspectorate has an important part in :he preparation of the above noted regulations as well as in the supervision and execution of the entire law. Until the passage of this law, when an industry needed a license, it «ras granted by the municipal authorities. Both the regional officer for en- /ironmental hygiene and the regional labor inspector were asked for advice. Under the new law the provincial authorities will have the responsi- bility for giving licenses for those industries that have an important air pollution potential, since significant air pollution doesn't stop at the Dorders of license-giving municipalities. Therefore, granting the license Dy the province can give better protection against air pollution to sur- rounding municipalities. Under the new law, the regional publich health officers and labor in- spectors will still advise the provincial authorities. This gives an essen- tial role to officers who are experts on environmental and industrial hygiene tfe expect that in general their advice will be followed by the licensing au- :horities, both because of their competence, but also because, if the advice 237 is not followed, there may be an appeal to the Crown. The Council of State, acting for the Crown, is in fact the ultimate authority with respect to the granting of licenses and the restrictions applied. Not all licensed industries are of equal importance. In the present transition period--before the enforcement of the new act — a number of smaller industrial pollution sources can remain under the existing legal rules. For these smaller sources a number of general directives, based on practical experience, will be framed. These directives may apply to classes of apparatus or to special industrial groups. Under the new act such direc- tives will attain official status. The attainment of an official status also applies to air quality and emission standards which, until now, have not been official. Such standards will be handled very carefully to prevent them from becoming licenses for freely polluting the air up to a stated limit. Especially for industrial air pollution, such a result could occur. Under the new act such undesirable outcomes can be prevented in two ways. Firstly, industry can be compelled to use the best available tech- nology, the best practical means to avoid air pollution. Secondly, a plant's emissions can be limited by taking account of other, nearby, emitters, which together are not allowed to surpass the established emis- sion limit. Such limits should not be looked upon only as values which should never be exceeded. The probability of transgression should also be consid- ered. It will be clear too that the limits need not be applied everywhere, but that they may differ according to the region. In an industrialized region they need not be the same as in a recreational area. Even when all its details of the new act have been worked out, it will not be possible to handle air pollution by simply applying the assessed rules. In contrast to the quarrels between the bleachers and brewers in former days in Haarlem, our recent experience with the establishment of new, big industries has taught us that consultation in an early stage of planning gives the best results. Above all an appreciation of the govern- ment's efforts for clean air for the sake of public health, and prepared- ness by industry to collaborate in these efforts is necessary. We in The Netherlands are fortunate that there is a growing awareness of the existing problem by Dutch industry, even when the measures to be taken will require considerable sacrifice. New industries have to look at such sacrifices simply as a part of their condition for establishment. For existing, older factories which have to apply for a license on account of the new act, the situation may be more difficult. In some cases, depending on special conditions, such an undertaking may get financial support from a fund built up from contribu- tions by all air polluters. The general rule that the polluter has to pay applies in The Netherlands to air pollution as well as to other froms of environmental contamination. Beside all the implications of the air pollution act, it is necessary to point to the legislation for town and country planning which obliges municipalities to establish plans in which special areas can be indicated for industry, preferably outside residential areas. In general we must more and more strive in the future, as John Evelyn pointed out, for a situation with separated areas for industry, housing and recreation, not because we couldn't get the air pollution problem as such in hand, but 238 rather because accidents and human faults will be unavoidable, whatever we do for the prevention of such events. Although industry can be compelled to perform its own control measure- ments, the just-mentioned air pollution fund will also have to supply the resources for financing the general costs of the enforcement of the act. These costs may apply to man-power, not merely for the central government but also on regional levels where the amount of expertness is still rather scanty at this moment. Most importantly, the fund has to finance the mea- surements and measures for controlling air pollution. Those measurements are the responsibility of the licensing municipal and provincial authori- ties. The task of the central government is "to supervise the supervisor." In order to get acquainted with the trend of the air pollution, a start has been made for establishing a national monitoring system. It will consist of 150 to 200 sampling stations, scattered over the country, for continuous automatic monitoring of sulphur dioxide with telemetering of data to one central point, the State Institute of Public Health (Rijks In- stituut voor de Volksgezondheid) at Bilthoven. It is intended that the monitors will in the future also measure other components, such as nitrogen oxides and ozone. The complete system is supposed to be in operation with- in five years. It is being developed as an integrated system which does need to be serviced at only three month intervals. The results will be continuously available at the central institute. It is intended that regional and local monitoring systems be connected with the national network. Some of these smaller systems, with a greater sampling density, are already in operation. Of course the new act has its sanctions. Of the penalties, created by King Edward I, we don't think any longer about confiscation of goods, but the closing down of an undertaking is still possible. As to today's desire of some people to torture the managers of some polluting factories, we hope to sublimate these aggressive feelings into a better and more adequate un- derstanding of the existing problems. For that purpose, more research will certainly be necessary. The Or- ganization for Applied Scientific Research (T.N.O.) has already made a significant start on such work and important investigations are well under way. Other institutes are doing the same and there is close cooperation with industry as well as with institutes abroad. International cooperation is indispensable for a small country like The Netherlands. Our country takes part in many international commissions and a start has been made for close cooperation with the adjacent countries, West Germany and Belgium, first of all, for laboratory research. Our Queen, when she opens the discussions in our Parliament on the third Tuesday in September, every year, always ends her speech with the prayer that God may give wisdom and power. We all are facing a heavy task and a great responsibility for which we too will need wisdom and power. 239 EVALUATION OF THE PRESENT SITUATION AND THE GENERAL TRENDS OF ACTIVITY IN THE PROTECTION OF THE AIR IN POLLAND By Jacek Janczak Director of Air Pollution Control Office Central Water Resources Administration Warsaw, Poland The protection of atmospheric air against pollution occupies a key- position in the complex of problems related to the protection of man's en- vironment. A skyrocketing growth of the negative effects can be seen when speci- fied size of production is exceeded, and, along with it, the volume of sub- stances issued into the atmosphere by the power, chemical and metallurgical industries concentrated in relatively small industrialized areas. Motor traffic makes things still worse. The adverse effects of the contamination of the air appear on a large scale in highly industrialized countries, par- ticularly in the United States, but also in the Federal Republic of Germany, Britain, France, the German Democratic Republic and elsewhere. The disaster- ous smog that hit London in 1962, killing no fewer than 4,000 people is well known; similar cases were reported in Los Angeles, Donora, and other indus- trial centers. In highly industrialized countries the protection of the environment has become an economic and political issue. Statesmen and pol- iticians pay particular attention to combating the contamination of the atmosphere and waters by industries. Equally well known is the report of the United Nations Secretary General U Thant of May 1969, some statements by President Nixon of the United States, Premier Chaban-Delmas of France, or by representatives of the governments of Holland, Sweden and other coun- tries. In Poland, the Polish Committee for the Protection of Human Environ- ment was set up at the Council of Ministers in 1970. Throughout the world intensive research is going on with a view to limiting the emission of dust and poisonous gases into the atmosphere, to finding new production technol- ogies to eliminate the emission of pollutants, new methods of desulphurizing fuels and to developing highly efficient installations for reducing the pollution . The Pollution of Atmospheric Air in Poland The course of events in Poland corresponds to the mechanisms observed elsewhere in the world. It should be noted that weather conditions in Poland are generally less advantageous than in other countries. This is so because of the relatively high duration of meteorological calms (15 to 20 per cent in an average year) and the frequency of inversions (which occur every two to three days) that promote the growth of concentration of pollu- tants in the air. The problem of air pollution is particularly acute in big industrial centers, chiefly in the Cracow-Silesia Industrial District and in the vi- cinity of huge industrial projects, such as the Lenin and the Bierut Iron and Steel Works, the Turoszow power plant, the Nitrogen Works at Pulawy, the 240 Plock refineries and petrochemical industries, the Aluminum Plant at Konin, the cement mills at Nowiny and Chelm, the sulphur basin in the region of Tarnobrzeg, and a score of other places. The situation in the Upper-Silesian Industrial District and on the adjacent areas is becoming particularly serious in view of its rapid indus- trial development combined with the continued operation of many outdated industrial establishments, often built in the 19th century (some coke plants, zinc plants, iron and steel works, steam-engined hoisting machines in colli- eries, etc.) , as well as with the fact that most houses in that region are heated by means of coal stoves. The chief fuel used in that region, both in industry and in homes, is coal with a high sulphur content. The degree of insolation in that region is smaller than elsewhere in the country. A rapid growth of damage can be seen in the area since 1962-1964. Previously obtained knowledge of the degree of air pollution in Poland is unsatisfactory because of the small amount of reliable data, caused first of all by the lack of adequate measuring equipment. We do not yet have full economic and statistical data for determining the influence of air pollution on the environment. The observations that have been made and the measurements we do have at our disposal testify nevertheless to the increas- ing gravity of the problem of air pollution in this country. A survey carried out in 1967 by the Ministry of Forestry and the Timber Industry indicates that 240,000 hectares of woodland, or three per cent of the total forest area in Poland, was damaged by air pollution. No data have been obtained as yet regarding the degree and scope of the adverse effects of industrial pollution on agricultural production. In this domain it is particularly difficult to make an inventory of the losses be- cause the life of agricultural plants is short when compared to forest flora. Nevertheless, on the basis of observations made it can be assumed that the scope of adverse effects of industry on agriculture is also considerable. Pollution can directlv cause a reduction of yields (the region of Olkusz) , a decrease of the value of products from the point of view of consumption or processing (the region of Konin), or a destruction of crops (e.g., in the neighborhood of zinc plants, as in Miasteczko Slaskie) . The concentration of some elements emitted by industry in the tissues or on the surface of plants can also lead to diseases and deaths of animals (fluorosis in the regions of Konin and Lubon) or even cause grave diseases in man (poisoning by food containing excessive quantities of nitrogen compounds) . The damage caused by industry is therefore serious, and will show an upward trend as industry continues to develop. The problem is becoming in- creasingly important from the point of view of the economy. On the basis of a 1967 study embracing 14,000 industrial establishments it was possible to define the regions of the country in which there was a concentration of works which worst affect the environment. Over 300 fac- tories were selected as the main sources of air pollution which should be the subject of anti-pollution moves prior to other establishments. These three hundred works are believed to be responsible for 50 to 60 per cent of the total emission into the atmosphere, which is estimated at 4 to 5 million tons of dust and 2 to 3 million tons of sulphur dioxide per annum. These selected establishments are being inventoried annually with respect to their emission of pollution. They emitted an estimated 2,339,000 tons of dust in 1967 as against 2,062,000 tons in 1970; whereas the amount of gaseous pollu- tants, chiefly sulphur dioxide, was defined as 1,159,000 tons in 1967 and 241 1,656,000 tons in 1970. With the investment plans for the current five-year period it is esti- mated that the installed dedusting devices will be able to retain annually some 600-650 thousand tons of industrial dust. In other words, dust emis- sion will be cut down by about five per cent every year despite a concurrent growth of industry. However, industrial growth will cause an increase in the emission of noxious gases, chiefly sulphur dioxide, of about 6 per cent annually. Throughout the world there are no know efficient and economical methods of curbing the emission of SO2 produced during burning. The con- siderable growth of industrial production envisaged for the present five-year period will cause the appearance of this problem in more regions of the coun- try. While it is estimated that the emission of dust by the examined works will be cut down by some 17 per cent (or 360,000 tons) as compared to 1970, despite significant growth of industry during that period, the emission of gaseous pollutants will rise by nearly 31 per cent over the 1970 figures. In 1969 the Central Water Resources Administration outlined the general directions of activity in the field of air pollution control and for combat- ing the effects of air pollution. This complex program of activity will be carried out as rapidly as resources allocated for the purpose will permit. The protection of the atmosphere is no simple matter and positive results can be obtained only by means of simultaneously solving of the problems discussed below. Legislation The first legal regulations concerning the protection of atmospheric air issued in 1954 authorized the setting up of appropriate bodies in the state sanitary inspectorate. The next step in this domain was the resolu- tion of the Council of Ministers of 1961 concerning the lowering of air pollution in Poland, particularly in the Upper-Silesian Industrial District. Organized activity on a broad scale, however, began only when the Council of Ministers decreed in 1965 the setting up of the Bureau for the Protection of Atmospheric Air in the Central Board of Water Economy. During the first period attention was focused chiefly on the prepara- tion of a bill for the protection of atmospheric air against pollution, which was adopted by the Seym in 1966. Also a number of executive regula- tions were issued which established: permissible concentration of pollutants in the air; protection zones; the obligation to make measurements; permissi- ble emissions; the principles of administering fines when the permissible level is exceeded, etc. However not all parts of the bill have been fully implemented, because of limited means of action. No new legal acts are to be introduced in the immediate future, other than amendments to previous norms setting permissi- ble levels of concentration of pollutants in the air, width of protective zones, etc. Diagnosis A knowledge of the concentration of pollutants in the air (immision) , based on measurements, is the point of departure for the pursuit of a proper policy with regard to air pollution control. Exception within the protective zones of individual works, measurements of pollution of atmospheric air are made by units subordinated to the Ministry 242 I: Health and Social Welfare. Factories are obliged to examine the concen- Jration of pollutants in the air within their protective zones and measure lie emission of pollutants. Units of the Central Water Resources Adminis- tration measure emissions for sake of control. The Ministry of Health and Social Welfare has designed a nation-wide ;asuring network, which has so far embraced chiefly the areas of towns and ?ttlements. At the moment this network, which is oriented mainly at mea- lring pollution from the point of view of the health of the population, is ide up of some four thousand measuring posts scattered all over the country. Measurements made so far consist in determining the amount of dust in le air at 2,500 places (using the sedimentation method) and the concentra- Lon of sulphur dioxide (using the contact method) in about 1,500 places. ;iis has made it possible to obtain initial knowledge regarding the state f pollution of some regions of the country. However the methods employed, lid the very diversified measuring equipment used, mostly home-made, do not How the determination of short term concentration of pollutants nor of jianges in concentration with time. The scope of measurement will be broad- lied as modern equipment is acquired. The existing measuring network has so far not been adapted for signal- ing the occurence of pollution in excess of permissible concentration, ich as may take place in highly industrialized areas during unfavorable gather. Neither is it able to supply information that will make it pos- sible to lower the emission of pollutants in a critical situation. There- 3re a special measuring network, a so-called alarm network, is to be set •p and connected with the existing network. The new network is to be based n instruments which continuously determine the pollution of the atmosphere y dust and gases and which measure actual weather parameters. This will ake it possible to forecast the level of air pollution. The alarm network, which will be run by the State Institute of Hydrol- gy and Meteorology, is planned to be set up in the worse polluted areas, uch as the Silesia-Cracow Industrial District, and the regions of Plock r Konin. The system will signal the anticipated excessive concentration f pollutants, mainly of sulphur dioxide, which chiefly occur during still eater, inversions and fog. When these conditions appear it will, for xample, be necessary to cut down the emission of sulphur dioxide from ower stations by shifting temporarily to coal with a lower sulphur content r by lowering power generation while increasing it in plants situated out- ide the alarm area. As for the measuring of the emission of pollutants in factories, the atter are obliged to measure the emission twice a year to provide a basis or checking the effectiveness of pollution control installations and for stablishing the amount of pollution emitted. At the moment this obliga- ion is not being met in full, if only for the lack of appropriate equip- ient ; hence the amount of pollution is often determined on the basis of stimates. Air protection units have been set up at fifteen voivodship labora- ories for the examination of water and sewage, the aim of the units is irst of all to take control measurements of the emission of pollutants rom factories; further such units are being organized presently, but so ar they are experiencing a scarcity of indispensable apparatus. At present time, only two kinds of instruments for measurements of ust emission in stacks are manufactured in small quantities by the Auto- lation and Mechanization Works at Kety. There is an urgent need to start 243 in this country large-quantity production of fifteen more types of measuring instruments to meet the demand in this domain. Investments Aimed at Curbing Pollution Investment outlays in industry aimed at the protection of the atmos- phere were first included in the National Economic Plan for the years 1966-1970 and amounted to 2,520 million zlotys. This included first of all the building of dedusting equipment and of installations for reducing some gaseous pollutants. This activity was concentrated in about two hundred works of five basic industries: mining and power, heavy industry, chemis- try, engineering industry, and the building materials industry, which pose the worst threat to the environment, and which are situated in the five worst polluted voivodships: Katowice, Cracow, Opole, Wroclaw, and Lodz. Air protection in those regions accounted for nearly 62 per cent of the national total. The inventory of factories requiring special investment to prevent air pollution is updated every year by the Chairman of the Plan- ning Commission at the Council of Ministers. The proposed investment plan for the years 1971-1975 indicates the ne- cessity of spending 4,000 million zlotys, or about 180 per cent of the sum actually spent in the period 1966-1970. Anti-pollution investment projects will be carried out in 216 factories. For the first time the plan also em- braces light and food industries. The concentration of outlays in the worst affected voivodships listed above will continue and again about 62 per cent of the total outlay will be earmarked for these regions. Other Means of Air Protection During the last four years, i.e. since the law was enacted, a number of other undertakings aimed at limiting the amount of pollutants emitted into the atmosphere were started in addition to the installation of anti-pollutior equipment. Worth mentioning here is the air-tightening of some production lines and plants; the shift from coal to gas or liquid fuel in some power generating installations; the replacement of steam engines by electric or diesel traction; and the introduction of central sources of heat. Besides this, high chimneys are being built to disperse pollutants, particularly sulphur dioxide, to a greater degree. Although this activity has produced some effects, such as the decrease of emission and of the concentration of pollutants in the atmosphere, indus- try should nevertheless put greater emphasis on a broader introduction of changes to the techniques of production that cause high emission of pollu- tants. This trend can be observed throughout the world. A considerable improvement of the quality of air in urban agglomera- tions is attributed to the development of central heating systems, develop- ment of gas supply and electrification of railways. As was mentioned earlier, the development of motor traffic causes new problems connected with protecting the atmosphere. It seems absolutely necessary to solve the problem of desulphurizat ion of oil and to improve the quality of petrol. Siteing Policy The conflict between technology and the natural environment, which 244 grows in parallel with the progressing industrialization of the country, is caused among other things by errors in siteing industrial projects. The sharpness of the conflict may be reduced by a proper siteing policy, which requires proper knowledge of the existing background of air pollution (emis- sion and imission) , of geographical environment, the influence of physio- graphic conditions on the spread of pollutants, etc. Until 1966 no consideration for problems of air protection against pol- lution was given while approving the siteing of new industrial projects. Consequently a number of big projects were improperly situated and the errors resulted in the devastation of the environment in their vicinity, for example the Nitrogen Works at Pulawy. But from 1966 on, the principle of studying the plans for construction of factories for potential pollution of the at- mosphere has been the rule, although in some cases lack of necessary mea- surements has been an obstacle. Such knowledge, backed by the results of study of the state of pollu- tion, can serve as an argument for or against a proposed site for an indus- trial project. An improvement in this respect has been noted lately. It -is intended that there be set up at the State Institute of Hydrology and Meteor- ;ology a special center for the elaboration of siteing expertise on air pro- tection at new or developing industrial establishment sites. [ Production and Use of Dedusting Equipment Production of dedusting equipment is coordinated by the Ministry of Heavy Industry through "Klima-Went" Amalgamated Producers. The draft plan for the years 1971-1975 envisages a nearly twofold growth in the production of dedusting equipment as compared to the previous five years. This growth will result from the commissioning of new production centers and the develop- ment of an improved dedusting technology. As a result, the home demand for dedusting installations should in principle be met around 1973. The program of development of this production can be viewed as adequate. On the other hand, the production of equipment designed to reduce the emission of gaseous pollutants is not sufficiently developed, particularly with regard to equipment for chemical industries. In order to improve the efficiency of dedusting equipment, it is plan- ned to intensify control activity. Fines are administered to factories that do not fulfil their duties. These fines contribute to the incentive for reduction of the emission of pollutants. Research and Science Base About forty research units, subordinated to individual ministries or to university schools, are presently engaged in research concerned with the protection of atmospheric air. Most of them, though, can hardly be classi- fied as independent scientific units because of small staff (one to three specialists) and inadequate laboratory equipment. In 1969 the coordination of research work was entrusted to the Presi- dent of the Central Water Resources Administration, and this allowed an evaluation of research plans for the years 1971-1975 by the Council for the Protection of Atmospheric Air. At present the main trends of research include problems of determining the conditions of dispersion of pollution in the atmosphere, of methods and 245 installations for curbing the emission of dust and gases into the atmosphere, with particular emphasis on sulphur and nitrogen compounds, methods of mea- surements; and of designing measuring equipment. The necessities for the coming period include concentration on development of a scientific base, and improvement of the situation with regard to modern equipment and specialized instruments. Outlays for this research are to multiply ten times in the years 1971-1975 as compared to the previous five-year period. Training A proper staff of specialists is one of the basic needs for combating air pollution. The Central Water Resources Administration has worked out a program of postgraduate studies. Such training is already going on in the Silesian Polytechnic at Gliwice, at Warsaw Polytechnic and at Wroclaw Poly- technic. So far forty-eight persons have completed the course and ninety more still are undergoing training. The organizational and curriculum as- sumptions for a two-year school for graduates of secondary general educa- tion schools to be opened in 1971 has also been elaborated. A program of senior courses for those responsible for air protection in industry, and supervising this protection on behalf of people's councils, has also been worked out, and training begun in 1970 in the Central Water Resources Ad- ministration training center at Debe , with some seventy persons partici- pating. Another program for the years 1971-1975 takes into account the needs of all branches of the economy and voivodship pollution-control bodies. All in all, the programs will provide additional training for 280 engineers in postgraduate studies and for 570 engineers and technicians in senior courses. A forecast of the demand for engineers and technicians skilled in pollution-control is being prepared for the period up to 1975 and up to 1985; it will serve as a basis for the organization of a network of schools. Conclusion In coming years, the protection of atmospheric air against pollution in Poland will concentrate on the following issues: To acquire better knowledge of the pollution of atmospheric air, and To reduce the emission of gaseous substances, particularly sulphur compounds. Full knowledge of problems of dispersion of pollution will create a foundation for the pursuit of a proper industrial siteing policy and physi- cal development of the country. Measurement of the degree of air pollution will provide the basis for the elaboration of a program of improving the situation in the worst affected areas, which will allow concentration of technical and financial resources. The creation of the alarm system will help to control the most polluting industries, among other things through burning fuels with low sulphur contents in unfavorable weather. In view of the very limited possibilities of obtaining low-sulphur fuels it is demand necessary to undertake research into economical methods of desulphurizing exhaust fumes. A replenishment of present equipment and the training of specialists will be indispensable in carrying on complex research into the aforemen- tioned problems. 246 THE IMPACT OF ATMOSPHERIC CONDITIONS ON THE DISSEMINATION OF SULPHUR DIOXIDE By Regina Hryniewicz State Hydrological-Meteorological Institute Warsaw, Poland The state of pollution with sulphur dioxide of the atmosphere of an area under investigation depends, on the whole, on the amount of emissions of this gas in that area. However, the concentration of sulphur dioxide, neasured in the near-soil layer, is determined by a number of other factors ; as well, such as meteorological and topographical conditions, and the occur- ence in the atmosphere of substances that may react with sulphur dioxide. «• It is not always easy to define the impact of meteorological conditions on the concentration of sulphur dioxide, especially when the sources of emis- sion are numerous and their characteristics are different, for example, short and tall chimneys, varying intensity of emissions and their location in the investigated area. As a rule, such a variety can be found in big urban ag- glomerations, where there are a lot of chimneys of home fireplaces, as well jas industrial chimneys. Since the measurements of sulphur dioxide carried out by the State Hydrological-Meteorological Institute are fragmentary, they do not permit full definition of the impact of atmospheric conditions on the state of pol- lution of a given area. At present, it is even difficult to know what nethods should be applied in sampling air, in order to obtain a full account b,£ the state of pollution of the atmosphere of a given area with minimum effort. Sulphur Dioxide Concentrations Measured in the Near-Soil Layer 1 Measurements were carried out twice a day in one place in Warsaw over a period of 5 years. It has been found that sulphur dioxide concentrations changed in cycles within one year, from maximum values in the winter to min- imum values in the summer. Similar changes in concentrations very often have been registered in other regions, for example, in Katowice, Cracow and Zakopane. A chronological course of average monthly concentrations in War- saw-Bielany is presented in Table I, separately for 8 AM and for noon. Such a course of monthly concentrations seems to be obvious because of the increased emissions of sulphur dioxide in the winter. However, the dif- ferences between summer and winter are greater than one might expect them to be, judging by the differences in emissions. The meteorological conditions in the winter are less conducive to the diffusion of pollution and to sulphur dioxide changing into other sulphur compounds, e.g. to serosols. As docu- mented by measurements carried out in Warsaw in the winter, only abour 10 per cent of sulphur occurs in the form of sulphates. In the summer, however, this percentage increases to reach 30 per cent. In our climatic conditions, precipitation is higher in the summer. Therefore, sulphur dioxide is eluted by precipitation more effectively in the summer than in the winter, in spite of diminished emissions. On the basis of measurements of sulphate concen- trations in precipitation, it has been found that the average amount of 247 sulphur washed out of atmosphere by precipitation totals 5 kgs per hectare in the summer, and only 4 kgs per hectare in the winter. All these factors cause sulphur dioxide concentrations to be many times smaller in the summer. In Warsaw, summer sulphur dioxide concentrations are four times smaller in the morning, and five times smaller at noon, than those in the winter. It has been found in Katowice that a measurement station surrounded by a large number of sources of emissions registers greater differences between concen- trations in both winter and summer, than a station located on the outskirts of the town. In the former this ratio is 3 to 4, and in the latter 2 to 3 . The data obtained in Katowice indicate indirectly that sulphur dioxide moves from the sources of emissions faster in the summer than in the winter. In the atmosphere, sulphur dioxide is not only dissipated mechanically, but also is absorbed intensively by basic dust particles, as well as oxidized, as a result of the influence of physico-chemical factors. Thus, when sulphur dioxide covers the distance from its sources of emission rapidly, more of it gets through than when it moves more slowly. Even if the phe- nomenon of mechanical elution of sulphur dioxide in the atmosphere did not exist, its concentration would gradually diminish, as a result of the in- fluence of physico-chemical factors. Laboratory experiments and estimates show that in industrial regions the half-life of this gas varies by several hours . The daily cycle of sulphur dioxide concentration depends, first of all, on the character of emissions in a given area. In Warsaw, concentrations are lower at noon than in the morning. In the winter, the noon concentra- tion is about 78 per cent of that measured in the morning; in the summer, about 60 per cent. These figures for Cincinnati, U.S., are 80 per cent for the winter and 50 per cent for the summer. Thanks to favorable atmospheric conditions, the noon concentrations are lower than the morning ones. These differences are smaller in the winter than in the summer. In Katowice, how- ever, a noon decrease in average monthly concentrations is observed only in the summer. In other seasons, the noon concentrations are the highest. This is due to a large increase of emissions from industrial plants and home fireplaces during the day. Measurements in Zakopane, where there are only chimneys of home fireplaces, indicate the existence of close interdependence between concentrations and the period of heating the ovens. Average hourly concentrations in two-week periods in Zakopane are presented in Table II. The fluctuations of concentrations measured in Warsaw in the morning are illustrated by the distribution of concentrations presented in Table III, The distribution of concentrations is, more or less, logarithmic-normal. The differences of concentrations measured at short intervals of time in one place are very large from to 700 micrograms per cubic meter. Such great differences occur during the whole measuring period, and not only in Warsaw. Even in Katowice, in a place surrounded by a large number of sources of emissions, measurements carried out at several-hour intervals revealed con- centrations varying from zero to hundreds of micrograms per cubic meter. It can be said that change of sulphur dioxide concentration with time is a characteristic feature of these measurements. Similar fluctuations were observed in measurements carried out simultaneously in places situated sev- eral or ten-odd kilometers from one another. And again, it is a character- istic feature of the spatial distribution of sulphur dioxide concentrations. For example, the co-efficients of correlation of ranks for hourly concentra- tions were measured in three places in Katowice at the same time, on three 248 different dates (Table IV). They vary from the value of +0.8 to -0.7 and are usually the highest at noon. This is probably due to more intensive air circulation, as a result of which sulphur dioxide mixes with the air better. In two places in Zakopane, situated 2 kilometers from each other, the co-efficient of average daily concentrations measured in February 1970 was 0.665, while the co-efficient of correlation for average fortnightly concentrations in terms of one hour increased to 0.91. Co-efficients of correlations of ranks between average daily concentrations in various places in Brussels varied from 0.4 to 0.8 and changed from month to month. It follows from the above considerations that it is not easy to know which measuring stations in a given area are the most representative. Neither is it easy to define the indispensable minimum number of stations because of the extremely irregular distribution of sulphur dioxide concen- trations in time and space. The Interdependence of Average Monthly Concentrations of Sulphur Dioxide and Climatological Parameters The average monthly concentrations in the morning in Warsaw have been analyzed based on measurements carried out over a period of 5 years. It can be assumed that between 1966 and 1970 no major changes took place in sulphur dioxide emissions in Warsaw. It should be stressed that the inflow of this gas from other regions is out of question because sulphur dioxide concentra- tions diminish very quickly as the gas moves away from the sources of emis- sions. For each month, an average concentration over a period of 5 years has been calculated: C^ and £\ c i~^i~"^i5 > where "C^ is the average concentration for a given month in a given year. The results are presented in Table V. 2\Ci is the highest for winter months and the lowest for summer months. In Warsaw, because of the very low level of sulphur dioxide concentrations in the summer, as well as because of the small fluctuation in these concen- trations, their analysis seems to be useless, taking into account meteoro- logical conditions. It can be assumed that, with the existing level of emissions in Warsaw, meteorological conditions cause the gas to be spread well in the summer, and that fluctuations of meteorological parameters cause unimportant changes in concentrations, not very different from the generally low level. Only in December, January, February and March, are average con- centrations higher, and fluctuations of these concentrations larger. In the winter of 1966-1967, the lowest sulphur concentrations were re- corded, and in the winter of 1968-1969, the highest. For these two periods, the results of analyses of certain climatological parameters will be pre- sented. Deviations of average monthly values from the 5-year average have been calculated in similar manner to those for sulphur dioxide concentra- tions. The results of these calculations for temperature; monthly precipi- tation; number of days with precipitation; and average wind speed are pre- sented in Table VI. In the winter of 1966-1967, the deviations of temperature, monthly precipitation and the number of days with precipitation are positive, and in the winter of 1968-1969, negative. The deviations of the wind speed are small and no irregularities have been observed The deviations of the directions of the wind from a 5-year average are presnted in Table VII. 249 In the winter of 1966-1967, there were more winds from the western quadrant and less from the eastern one; in the winter of 1968-1969, there were more winds from the eastern quadrant and less from the western one. The data presented allow us to state that in certain periods climatol- ogical indices may indicate the influence of meteorological conditions on the state of atmospheric pollution even when they act in one direction only For example, in the winter of 1968-1969, lower temperatures, lower precipi- tation, smaller number of days with precipitation and a high proportion of winds from the direction of the main sources of emissions resulted in an increase of sulphur dioxide concentrations. In the winter of 1966-1967, meteorological factors acted divergently: the temperatures were low, but the amount of precipitation and the number of days with precipitation were large. The Influence of Meteorological Conditions on Average Hourly and Daily Con- centrations of Sulphur Dioxide The state of pollution of the atmosphere of a given region with a givei emission is determined, first of all, by the dynamic state of atmosphere in the near-soil layer, characterized by the vertical temperature gradient and the vertical profile of wind speed. However, not many of these data are available. For example, in the vicinity of Warsaw, the above-mentioned parameters are measured only twice a day. In Zakopane, where measurements of sulphur concentrations are carried out, aerological measurements are not conducted. However, there are two synoptic stations, one located about 1,200 m. higher than the other, as well as two climatological stations located at intermediate altitudes. Our fragmentary measurements of sulphur dioxide concentrations in Zakopane illustrate, to a certain extent, the influence of the vertical temperature gradient on the spread of pollution. During one of the measurement periods, from December 22, 1969 to Jan- uary 3, 1970, almost laboratory meteorological conditions occured. During that period, almost total calm prevailed, and there was no precipitation. The fluctuation of the vertical temperature gradient was the most important meteorological parameter that influenced the fluctuation of concentration. The gradient was established on the basis of observations at the above- mentioned synoptic and climatological stations rather than by the classic method. The dependence of sulphur dioxide concentration, in morning and evening hours, on the temperature in the place where air was sampled, as well as on the difference of temperatures measured at latitudes differing by 200, 700 and 1,200 m. , were investigated. The method of selection of predicting variables worked out by Professor Z. Kaczmarek was applied. The highest co-efficient of correlation was obtained for the gradient of temperature occuring when the difference of altitudes was 200 meters. The co-efficient rose insignificantly when the vertical gradient of temperature at the altitude of 1,200 meters was included. Other parameters were of no meaningful importance. The joint co-efficient of correlations for two var- iables was 0.854. In another measurement period, from January 18, 1971 to February 3, 1971, entirely different meteorological conditions existed. There was thaw, no inversion, nearly no precipitation, with several (ten-odd hour) periods of calm and or strong winds. In that period, winds had decisive 250 .nfluence on the state of pollution of the atmosphere. The dependence of he average daily concentration of sulphur dioxide on the number of hours )f calm on that day was defined. A very close relationship was found, ex- >ressed by the rank correlation a co-efficient equal to 0.895. Daily analyses of concentrations in Warsaw show that the negative jradient of temperature at altitudes not higher than 500 meters very often _s accompanied by an increase in the sulphur dioxide concentration. This s confirmed by the fact that average concentrations in the period of in- version in a given month are always higher than average monthly concentra- ions at that time of the day. To illustrate this, concentrations during i period of inversion, measured in the morning, are compared with monthly iverages in the winter of 1968-1969 as in Table VIII. As it results from j;he data presented, the differences are considerable. However, temperature inversion is not always accompanied by an increase 3f sulphur dioxide concentration. For example, between October 13 and 17, L969, inversions occured during the day (October 15 and 16) but no increases Ln sulphur dioxide concentrations were registered. At that time, there were ■|rlouds in the sub- inversion layer, it drizzled from time to time, and there vere long periods of mist. There was a visible increase in dustiness, and an analysis of dust revealed a very high content of sulphates, reaching 25-30 micrograms per cubic meter, which was as much as the content of sul- phur dioxide in air. An analysis of particles of mist and drizzle disclosed a. concentration of sulphates reaching 150-400 milligrams per liter. More- over, an increase of ammonium concentration in air was recorded. All this shows that in the period discussed mechanical elution was not effective, out there existed a number of conditions causing intensive transformation of sulphur dioxide into sulphates. This confirms observations made in the Soviet Union that in sub- inversion clouds the content of sulphates in urban areas is very high. It can be said that the clouds in a sub-inversion layer are a "broom" which sweeps sulphur dioxide out of the layer. The pressure field exerts great influence on the state of pollution of the atmosphere. An introductory analysis of synoptic situations in a period of increased sulphur dioxide concentrations in Warsaw has shown that these are periods of barometric stagnation on the edges of cyclones, in cold fields, or in zones before approaching fronts after a period of stable barometric (situations. A study of the statistical relationship between hourly sulphur dioxide concentrations measured in Warsaw and certain meteorological parameters, calculated according to Professor Kaczmarek's method of selection of pre- dicting variables, did not yield promising results. Joint co-efficients of correlations are not very high. In addition, different factors have decis- ive influence during different periods of measurement, and their number changes. For example, for a sample chosen at random from a three-year period, the joint co-efficient of correlation was 0.75 'with 0.25 for 6 par- ameters. On the other hand, the joint co-efficient of correlation for the winter of 1967-1968 was 0.54, and only for three meteorological elements. These results of statistical studies become understandable in the light of measurements in Zakopane, where, in the same year, fluctuations of sul- phur dioxide concentrations were determined by inversions in one month, and by winds in another. Of greatest importance for sulphur dioxide fluctuations in the period under investigation is the meteorological parameter which undergoes greatest 251 fluctuation during that period. On the other hand, the level of concentra- tions at which fluctuations occur depends on the stable level of one or another meteorological paramenter that influences the spread of pollution. Again using the example of Zakopane, January 1970, when the temperatures were low and there was no precipitation or wind, the average sulphur diox- ide concentration over a two-week period was 254 micrograms per cubic meter, while in the corresponding period of 1971, with no inversion or precipitation and with the temperatures above degrees Centigrade, the average concentration over a two-week period was 64 micrograms per cubic meter. During the first period, average hourly concentrations ranged from 50 to 1,500 micrograms per cubic meter, and during the second, from to 500 micrograms per cubic meter. Quantitative relationships between meteorological conditions and sul- phur dioxide concentrations are not easy to define. In the years to come it will be necessary to carry on measurements of sulphur dioxide in order to define the state of pollution of the atmosphere. Meteorological fore- cast still does not allow quantitative determination of sulphur dioxide concentration in the atmosphere. 252 TABLE I Average Monthly Sulphur Dioxide Concentrations in Micrograms per Cubic Meter in Warsaw-Bielany Month Year Hour I II III IV V VI VII VIII IX X XI XII 1966 8 oo 57 57 30 32 17 7 14 13 27 34 31 36 , U 30 51 41 21 21 11 6 12 8 15 25 34 31 1967 g00 54 41 55 56 37 22 17 31 35 38 66 81 ll 30 50 38 37 54 37 17 12 21 20 30 47 74 1968 8 oo 108 68 52 38 24 9 16 44 23 66 43 119 1X 30 101 70 42 19 14 5 16 30 23 41 35 67 1969 8 oo 152 138 114 40 32 25 20 23 23 21 41 63 ll 30 96 84 49 32 27 12 11 12 11 17 35 53 1970 8 oo 88 108 63 36 15 22 20 12 17 13 20 29 ll 30 75 76 52 12 5 11 6 8 13 27 19 25 253 TABLE II Average One and Two-Hour Sulphur Dioxide Concentrations in Micrograms per Cubic Meter in Zakopane in the Periods: Dec. 22, 1969 Jan. 3, 1970 and Feb. 7, 1970 Feb. 19, 1970 Hour Average sulphur cioxide concentrations in the period 22.12-1969 3.1-1970 7.02-1970 19.02.1970 Rownia Krupowa Rownia Krupowa Sanatorium im. Chalubin 1 212 95 92 2 182 3 111 99 70 4 140 5 161 91 84 6 170 7 259 174 91 8 283 9 354 111 61 10 373 11 321 70 52 12 248 13 204 66 52 14 209 15 223 91 51 16 263 17 323 229 131 18 348 19 346 241 155 20 299 21 288 154 102 22 256 23 228 115 92 226 254 TABLE III The Distribution of Sulphur Dioxide Concentrations from Hourly Measurements at 8 AM The period investi- gated Sulphur dioxide concentration in micrograms per cubic meter r , E e ■H c ■rA Distribution in per cent e £ •rH a 2 Arithmeti average 10 30 50 70 90 95 98 Autumn 1965 3 2 15 20 28 30 40 45 16 1966 8 19 33 84 115 171 199 31 Winter 65 4 12 32 42 69 120 270 280 284 56 66^ 7 19 61 130 154 176 193 44 Spring 66 2 9 15 30 60 95 110 118 27 67 6 38 47 59 83 91 134 197 50 Summer 66 3 8 13 40 43 45 64 11 67 2 10 16 31 38 56 118 120 24 Whole 1.9-66 year 31.8-67 10 | 26 46 87 117 155 199 37 255 TABLE IV The Co-Efficient of Correlations of Ranks for Sulphur Dioxide Concentrations Measured in Three Places in Three Hourly Periods in Katowice 1-Warszawska 2-Planetar ium 3-Airport Measurement Points 1 2 1 3 2 3 The date of Month/measure 7 oo 12 oo 7 oo 12 oo 7 oo 12 oo 19 oo I 1969 0.585 0.774 0.512 0.501 0.601 0.356 II 69 0.727 0.485 0.632 0.516 0.590 0.694 III 69 0.454 0.496 0.216 0.708 0.450 0.535 0.383 IV 69 0.597 0.609 0.629 0.446 0.378 0.316 -0.171 V 69 0.632 0.646 0.433 0.807 0.470 0.880 0.091 VI 69 0.479 0.249 -0.048 0.343 0.514 0.325 0.335 VII 69 -0.092 0.173 0.478 0.597 0.152 0.059 0.077 VIII 69 0.442 0.502 0.183 0.277 0.234 0.259 0.089 IX 69 -0.103 0.127 -0.086 0.436 0.032 0.535 0.439 X 69 0.424 0.510 0.059 -0.082 0.434 -0.752 0.011 XI 69 -0.071 0.567 0.020 0.593 0.110 0.169 0.445 XII 68 0.290 0.512 0.248 0.461 0.248 0.385 256 TABLE V Deviations of Average Monthly Concentrations from Monthly Average in 5 Years Month C i5 Average sulphur dio- xide concentration in 5 years in micro- grams per cubic meter A C i = c i - C i5 Difference between average monthly sulphur dioxide concentrations and and average concentrations in 5 years in micrograms per cubic meter 1966 1967 1968 1969 1970 I 91.5 -34.7 -38.0 + 16.2 +60.0 -3.7 II 82.5 -25.1 -41.6 -14.5 + 55.7 + 25.4 III 62.7 -32.5 -7.6 -11.0 +51.0 +0.3 IV 40.2 -8.2 +16.1 -2.7 -0.4 -4.6 V 24.9 -8.4 + 12.5 -1.0 +6.7 -9.6 VI 16.9 -9.6 + 5.4 -8.1 +7.8 +4.6 VII 17.5 -3.7 -0.1 -1.2 +2.3 + 2.8 VIII 24.6 -11.6 +6.6 + 18.9 -1.2 -12.6 IX 25.1 -2.3 +9.9 -1.8 -1.9 -8.6 X 34.6 -0.8 + 3.8 +31.8 -13.8 -22.2 XI 39.9 -8.5 +25.7 +3.0 +0.6 -20.4 XII 65.9 -29.4 + 15.3 +53,6 -3.0 -36.2 257 H > W e o S-I m en G o ■H +J id ■r-l > QJ Q C rd in >-i (13 01 -p to (U M P rO Sh QJ CU id e q id QJ -p QJ (U CO c c - - •H C C IS O O CO QJ en id M > < 0) 0) tT O id -i u a, fn .G Q> ,G ■P 10 -P C OJ c jQ -G o \ o> CTi (N r^ rH qj 'D CO VD • • • > in u to C vd cn O O o O ■r-l c 4-1 T> S-I a; i_i C OJ , — i C QJ Id >-l CT 1 QJ -P OJ u OJ r-l ■H 1 a> IW 5 U -p OJ T5 QJ S-i E K£> ^D • • • • i QJ S-I VD CTi o O o o ■r-4 01 > o Q, -r-1 > c QJ CTl rH + + 1 Q rQ id E CO 5 in id •r-l Q r-l QJ >1 4-1 o C to S-I QJ m r-l •r-l U 1 Ck >o m X 'V id qj C UD o> rH CN in m -p OJ -a qj E to • • • • -H QJ c OJ c in S-I U CN CM 00 ro l> > < o E en •H c 5 m -h OJ -p (0 S-I \ <^ -tf -tf CO O qj i id CO VO • • • • II m u 4-1 x id qj 4-1 & i CTl rH ^-i 1 1 1 mic QJ C >i -r-l r-l QJ rH | ■ r-| j_i QJ r-l )-! 5 ■H (C )_l C 1 QJ -G OJ Oi \ r- >£> iX) CN o <- 4-4 4-1 -P P c -§ CO >1 O C s-i QJ Qj -§ CO vD VX) > VD C?i 3 id , (0 , G to CT rH u >i a S-I >i ^ ^f CO o in id X QJ Id ■H -H 01 OJ id • • • • ■H Sh -P | tJ £1 u -P in s-i ^ -o CO r^ 3 4-1 •H Sh -P G QJ 3 4-1 < g C 2- Cu ■M -H >i !3 \ cn m CO CT CN ai 1 to CO >x> • ■ • • in V rC S-I 1 >i) ^0 m CN II -H c -P r a w id •rH rH ro CN rH rH US •H qj M c QJ r-l ■H Oh c (13 >i QJ QJ r-l to rH 1 1 1 1 £ 1 QJ QJ .c ■H .G id ■H S-I \ l> l> r^ rH CN 4-1 5 -p U c -P s-i in E QJ VO U3 • • • • CO o O O ■H QJ >-l -h > C c OJ CTl rH rH I CN CN Q rQ E Qi -P E id -h -r-l E rH + + + QJ >1 , c 1 to S-I fT r-l a rH QJ rH CN CT ro in id x ■--1 ■i-l 0) -rH -P E • • • • -H u •p u ■p in m E QJ g P- O rH irC QJ > < c E OJ V-l C4 id id -P C OJ ■H -H >i C •H E r-l ^f ^D CN ro o> en U X 1 rG CO v£) • • • • u id 3 •p in M -P 1 ixi en rH r-4 CN -* in c u -P c QJ G •rH CTl rH | 1 1 I II "H S-I id O E 4-J rH l-p sn qj > S-i X c ■H qj OJ (d OJ -P 4-1 QJ OJ \ l> v£> l> iX> CN ■P 1 IH 5 a cd S-I CO U T3 M3 ^D • • • • < "H IW ■p QJ E TD id qj m id lO o> CM o CN oo •H QJ rC QJ 4-1 G qj en £1 c S-I (Tl rH + + + + l-P Q A P -P A3 >i id +j ■r-l cr rH OJ >1 1 | QJ CT r-4 >-i CO c TS CTi CTi QJ 10 OJ id • • • • ■h s-i -p a, s-i in u u >-l U CN in ro o HP OJ > < c E E QJ 4J 2 id -P G QJ id -r-l N c •rH CTl o •H -P ' l ' + -G -P C H M H H H £ X H M H 258 \* * a •o do oo\ CM « \ + 1 ' ' it m \ o-'V \-o »r o » CM -o\ o o CM < u oo\ o- cm CM _ o *r CO CO * < * •0 \ •0 \ T + + + 1/1 » CM K o IS m * CO •o \ 0> CO o CM o *n K o o O ■0 \ + + II m k/> X K \«0 o m ,_ 00 <•> i m O CM ,J •*• CM CM CM \ * - o •o _ IS CM * ^ CM If) 00 \ 00 CM -6 m •o CM •0 X + + + + ii Iz \ .- \* m ■<»■ *\ o CO CM CM •n * s + 1 1 1 m K 00 o 0- |Ui — TT m CM \ O" O- \>0 o m 09 \ r- CM •— II uT -Iz ■O \ + V . UJ Z uT *\* CM CM 6 o CM — .. \o o ^! m z z M>\ + o < * \ ' , m m o 0> m 'zf - CM o o -c c £ X ~" = = 259 TABLE VIII Average Concentrations Within Month and During Periods of Inversion of Temperature at an Altitude Not Higher Than 500 Meters Month and Year XII. 68 1.69 11.69 III. 69 Number of days with in- version at altitude not higher than 500 meters 10 16 8 6 Average sulphur dioxide concentrations in periods of inversion of tempera- ture 174 201 258 278 Average monthly concentrations mg 50 2 /m 108 152 138 114 260 PERIODICAL MEASUREMENTS OF ATMOSPHERIC POLLUTION AND THEIR INTERPRETATION By Andrzej Kasprzycki State Hydro-Meteorological Institute Warsaw, Poland Introduction In meteorological conditions causing the highest increase of the con- centration of pollution in a given area, there arises the need to conduct periodical measurements of pollution immissions in the lower layer of the atmosphere. The aim of these measurements should be to gather the greatest possible amount of information on pollution at the lowest possible cost. Let us assume that we are given a set of measurements of atmospheric pollution X]_, X2 , X , obtained in a certain area at a definite date, forming an n-element random sample. The question is what the scatter diagram of such a set should be like, in order to obtain maximum information about the investigated phenomenon, with fixed index n (the number of mea- surements) . Introducing in the analyzed diagram statistical measure of information I (Z) equal to (3) : I (X,,X 2 ,..X n ) = H(X,)+ H(X 2 )+..+ H(X n )-l(X 2 I X,)- (Eq.l) — ...— I (X n |X|, X 2 ».. X n _|) where: H(X' )= entropy of the set, from which the element X-, has been selected i I I » Xg , . . Xp_ I )= statistical measure of information about the set from which the element X«[ comes. The information has been obtained as a result of observations of the X-^, X2, . .X -, sequence of elements. It is evident that the X^, X2,..X n obtained from the random sample will be maximal, when all conditional measures of information I (X^ X^,..Xj^_l) will equal zero, or when the random sample will be independent in space and time. On the basis of the results of numerous experiments made so far, it can be said that meteorological conditions, as well as concentrations of atmospheric contaminants constitute a random field in space, and a stochastic process with continuous parameters in time. Thus the temporal-spatial field of atmospheric pollution at each point has a definite, normalized correlation function r(t-t ',/o). one that: r (0;0) = l X (00 ;"]5)= r (t~ \ Q \ <» ) =0 We arrive at the conclusion that both in space and time, there exists a radius of correlation of the considered measuring sequence, which may be defined by the following relationships, sufficient for the task set: The radius of correlation of stochastic process T - Km r(t-t ;0)<0,2 ( Eq 2) t-t ~T 261 The radius of correlation of random field R limr(O-J) <0,2 \~p I = V(x-x )2 +(y-y )2 +(z-z )2 ( Eq . 3) ' l/> I — R" Drawing practical conclusions from the above considerations, it can be stated that: Measurements of instantaneous values of the concentration of atmospheric pollution at a fixed measuring point should be carried out at time intervals t, bigger than the radius of correlation T of the stochastic process formed by this measuring sequence. Measurements in a selected threatened area should be carried out at distances exceeding the radius of correlation of the random field R. Summing up, it can be said that for control of the air quality of a region, when an instrument for continuous measurement of the concen- tration of atmospheric pollution is available, it is useful to carry this instrument from one place to another during the period of periodical measure- ments. The Interpretation of Permissible Norms of Pollution of the Atmosphere Adherence to the permissible norm of concentration of atmospheric contaminants in a region can be ensured only by never exceeding both normalized average daily concentrations and average 20 minute concentrations. Control measurements should seek to find out whether these concentrations have been exceeded and if they have, in how many cases. The confidence interval of the results obtained is dependent on the weight of the problem considered. For example, in the case of emissions of highly dangerous substances to the atmosphere, the measurements of immissions in the pro- tected area should be conducted continuously, in order to ensure an almost 100 per cent confidence interval. The establishment of a permissible annual distribution function and estimation of the percentage range of the normalized quantile do not ensure a high enough degree of atmospheric pro- tection for the following reasons: The concentrations of contaminants in the atmosphere constitute temporal sequences with a high degree of auto-correlation (-T">0.5). Thus, when the permissible norms are exceeded, the phenomenon is not sporadic, but of long-lasting character. Yearly distribution functions do not fulfill the requirements of the ergodic process, that is, their expected value in time is not equal to the expected value in the space of variability of pollution concentrations in terms of probability calculus. Yearly statistical time series are not statistically homogenous, that is, they are determined by the random variability of the investigated phenomenon only. The Statistical Distribution of Pollution Concentrations in the Near-soil Layer of the Atmosphere Let us support that/* (X ,Y , Z ) denotes the concentration of any passive atmospheric pollutant in the point of the spatial field X ,Y o ,Z , and that 262 ~i means any random fluctuation that causes a change in concentration of a given pollutant in the discussed point in space. In the case of the field of atmospheric pollution in an area without sources, the following relation- ship, limited to the terms of the first order, is evident: ($/>(x , y ,z ,t) t J\ £i//>(x,y,z,t) (Eq.4) Thus, the change of the concentration of the pollutant can be considered as proportional to the random value ~T and the concentration of the substance in the atmosphere P(x,y,z,t) in this point of the field, in which, as a result of random fluctuations, there occurs the transformation of the sub- stance dr to the point of the field with the coordinates X ,Y ,Z in the time dt. Taking account of the fact that the local time derivative OP (X Q> y n> Z nt i) in the field of the meteorological element is connected \i with the time derivative of the particle 0/)(X > y > Z > t) by the relationship ' dt ^p(x 0> yo,ZQ t t) dp(x,y,z,t) — , . r at s d t ~ v ' grad p (x »y» z » f) (E< ^' 5) where v - wind spead, v qrad p (x,y,z,t) convective derivative, we obtain: c v dt d />(x,y,z,t) />(x,y,z,t)+I7grodp(x,y,z,t) (Eq.6) We will notice that in the case of the field of atmospheric pollution generated by point sources, increase of wind speed causes a diminution of pollution concentration and of the gradient of this concentration in a given point of the field, which is evident intuitively. Taking further into account that "^ and grad p (x,y,z,t) are always collinear, we arrive at the conclusion that in a fixed point of the stationary field of pollution, the convective derivative, exact to terms of the second order, can be considered as a constant quantity, characteristic for this point of the field. On the strength of the central limit theorem, proved in elementary statistics, the sum of the sufficient quantity of random variables influencing the investigated phenomenon has a normal distribution. Thus, in the case considered, it will be the function £j ~J that will have a normal distribution in a given point of the field, which results directly from the limiting qualities of the expression: n dp n=co y=| 'p+c * v^w (Eq. 7) where c = lT.grad p (x t y,z,t) = const. It follows from the above considerations that passive pollution of the atmosphere has a logarithmic-normal distribution. This has also been confirmed by experiments of numerous authors, for example^ ' '. Such a distribution can be sufficiently defined by three parameters: m - mathe- matical expectation, or the expected value of the logarithms of concen- trations, 6^ c the variance of the logarithms of concentration, C constant. 263 Estimation of the Parameters of the Distribution Function of Atmospheric Pollution on the Basis of Measurements Having at our disposal the results of measurements of immissions of atmospheric pollution in a given area, it is possible to estimate the distribution function of pollution concentration if the following require- ments, resulting directly from the above considerations, are fulfilled: 1. All measures have the same averaging time, that is, are 20-minute measurements, one-hour measurements, etc. 2. They come from a period meteorologically homogenous, that is, do not exceed a monthly time interval and are obtained under, more or less, the same meteorological conditions, for example, in a period of drought, with winds prevailing from one direction during a period of stagnation, etc. 3. They come from the same time of day, or if from individual times of day, their number is the same (e.g. in the case of the 24 -hour average concentration of pollution, on the basis of 20-minute measurements) . 4. They cover an area which can be regarded as homogenous from the point of view of the statistical distribution of pollution, that is, having similar vegetation and relief, and spatial dimensions much smaller than the distances from the basic sources decisive in a given meteorological situation (for example, a fixed wind direction) on immissions in a given area. In the remainder of this paper, I will confine myself to a presentation of a method for estimating the parameters of the log-normal distribution function of atmospheric pollution with the application of electronic com- puting techniques. A detailed analysis of the method of estimation of the parameter /MO.^, & t C is presented in reference 5. We introduce a new variable, determined by Equation 7, that means Z=log(^ + C) . Later we postulate that variable to possess a normal distribution, determined by the density function: ft) 2 ,(z)= ^b eX "(- ( S-)^ ( z;A^ From 7 and 8 it follows, that the three parameters m, £ , C completely determine the statistical distribution of the random variable p . Now we estimate these parameters by the method of moments. By the definition of population moments we have: CO £(/>)=/ pQ(p)dp (Eq.8.1) -CD ^ E(p-n\f= f (p-mfgip)dip -co where g(^) is the density function of the random variable. We now make a simplifying assumption; g(/o)=0 for pz-C (Eq. 8.2) 264 where C any positive number. That means we assume the random variable f> + C to be positive at all times. According to the postulate of the method of moments, we accept as the estimation of proper moments of a general population, the moments computed by random sampling. Taking into account assumption 8.2, we can write : 'P'-H&^JWWP (Eq.8.3) N -c where fT\^ S^ According to the postulated thesis the following equation is valid: g[ / )(z)] /J '(2)=N(z;A;3-)=f(z) (Eq.8.4) which immediately results from the general rules of the formation of the density function of transformed random variables (KACZMAREK 1970) . The change of variables in Equations 8.3 corresponding to the inverse relation to Equation 7, implies X=e - C, using Equation 8.4 after integration for the first order moment, and for the central moments of second and third order, yields following relations: y5 = exp(m + -l£2)-6 (Eq.8,5) S 2 =exp(2A+2d- 2 )-2(^ + C)exp(Ai + l H H ts&fJn T7£ exp i 26-2 — j 6p (E * ,0 > (5) As previous experience shows v , in an overwhelming majority of cases, Equations 9 proves to be sufficient for measuring atmospheric pollution. However, it sometimes happens that a negative value of parameter C^ results from calculations, with a modulus exceeding the smallest element of the random test. In this case, it is necessary to assume that C=0 and use in further calculations the following estimators: ■"42'oort ^=J_| (log/0r s )2 (Eq(|) The Estimation of the Rank of the Normalized Quantile on the Basis of the Distribution Function As was said at the beginning, the confidence level of conclusions to be drawn from measurements should be assumed initially, in accordance with the aim they are to serve. Passing to the confidence intervals of the parameters of the logarithmic-normal distribution function, we shall notice that, as it was proved in Reference 5, the exact Equations are practically useless. For large random samples the two first parameters can be estimated with the help of the normal confidence interval: a tao- t a |j + C) H ' J ' J-1.2. — k is determined by the frequency function N(zjlTlI* ) / which is a direct «/72 result of statistical properties of the distribution function of a mean of random variables, with the assumption that the size of the sample is 24 60 m i k i N Of course, a_ I 57 - ' ^7 > where, in the case of continouus measure- ments N=72k. The percentage rank of the average daily normalized quantile, estimated on the basis of a distribution function defined as above, should not be greater than: P 24 n= (t xj 0; I) (Eq.15) where tv = 7f {|0Q (A + C) — mf and ( t ; J I ) is the function of the normalized normal distribution, (with the expected value and the variance 1) . When the results obtained allow us to state that the normalized con- centration of pollution has not been exceeded, the following equations must be satisfied: For the 20-minute norm: P ( p< p 2 Q™) = $ (t^O™ *, 0\ I) < 0.9861 (Eq. 16) 267 where p^m the normalized 20-minute concentration of the pollutant, log^om + C)-^- ^~) t^m- N *-»■* For the 24 -hour norm of the pollutant: P(/>24n)»^(t^ 4 n;0;l)/72 V?2 ^N To allow us to state that the permissible norms of atmospheric pollution are exceeded at the assumed confidence level, the following inequalities must be fulfilled: P(/>0.986l (Eq, 18) log(/> 2 om+g)-(m+ffi ) where t' ' m = 20 A * J" For the 24 -hour norm where f ' ' n = P( / o< / o 24 n)=^(t^ , 4 n;0;l)>l- 1 [- (Eq.19) log(/024n+C)-fm+-^=r r J >/72 -/fZVTN In Equations 16 through 19, t^L mean absissas of the normal standardized distribution in the case of sample size N bigger than 100, or the absissas of the students "t" distribution for N-2 degrees of freedom in the case of a sample size smaller than 100, for the confidence level 1-*. If, on the basis of the parameters estimated through m, o, C measurements, it is not possible to determine that the inequalities 16 and 268 3.7, as well as 18 and 19 are fulfilled, then, at the assumed confidence level, the data do not permit us to decide whether or not the permissible norms of the concentration the pollutant in the atmosphere have been exceeded. It should be also stressed that, in the case of exceeding the normalized concentration of atmospheric pollution, the left side of the inequality 18 or 19 also defines the level of danger to the atmosphere, which can be interpreted as certain at the assumed confidence level. Conclusion The above considerations lead to the following important conclusions: 1. Control measurements of immissions of pollution in protected areas should be conducted only when meteorological conditions are unfavorable in the investigated region. 2. Areas in which measurements are to be conducted should be selected on the basis of a cartographic-mathematical analysis^', when meteor- ological conditions are definitely considered to be dangerous. 3. It is advisable to carry out mobile measurements in selected areas in order to minimize the time series correlation and to maximize the representativeness of measurement series for a given area. 4. The confidence level of the results obtained should be determined only by the degree of harmfulness of the investigated pollutant and by economic effects connected with exceeding the normalized quantities of atmospheric pollution. 5. A comparison of the results of measurements of immissions of atmos- pheric pollution in the form of distribution functions, as well as the hypothesis about the statistical logarithmic-normal distribution should be limited to periods of time in which the meteorological conditions can be regarded as qualitatively the same, (in a given region) , and to areas homogenous with respect to the expected average immission of a given pollutant. A comparison of results in the form of a yearly distribution function of atmospheric pollution distorts the true picture of emissions in a given area and has no justification from the point of view of statistics. 6. In case the conditions defined in conclusion 5 are met, the use of the 2-parameter logarithmic-normal distribution is permissible only in the first approximation. When applying electronic computing techniques, it is necessary to introduce the 3-parameter logarithmic-normal distribution, as described earlier in this paper. 7. Permissible norms of atmospheric pollution should not be allowed to be exceeded a certain percentage of time in a 1-year period. In principle, the normalized concentrations of immissions should never be exceeded. Percentage ranks of normalized concentrations of atmospheric pollution, estimated in control measurements, define the degree of danger to the atmosphere in a given region in definite meteorological conditions when these values are exceeded. Annotations 1. We have in mind continuous measurements, not correlated, which hypo- thetically can be carried out by moving the measuring instrument to the 269 next point of the polluted area and then returning to the initial point after a period of time equal to the radius of correlation of the time series considered. We have in mind the definition of regions of maximal concentration of pollution, on the basis of the solution of the diffusion equation for given meteorological conditions and the main local emitters. References 1. K. Haman - Introduction to the Physics of the Atmosphere, Warsaw, 1963. 2. J. Juda - The Planning and Interpretation of the Results of Measure- ments of Concentrations of Atmospheric Pollution, Bulletin of the Sanitary-Epidemiological Service of Katowice Voivodship No. 3, 1968. 3. Z. Kaczmarek - Statistical Methods in Hydrology and Meteorology, Warsaw, 1970. 4. A. Kasprzycki - The Influence of Meteorological Conditions on Average Daily Concentrations of Dust in the Lower Layer of the Atmosphere. The Publications of the State Hydrological-Meteorological Institute, Volume 97, 1969. 5. A. Kasprzycki - The Estimation of Parameters of Statistical Distri- butions for Certain Cases of Hydrological and Meteorological Random Variables. The Publication of the State Hydrological-Meteorological Institute, 1971, No. 102. 270 DRY AMMONIA PROCESS FOR SULPHUR OXIDE NEUTRALIZATION By Romuald T. Chrusciel Vice-Chief Coordinator for Abatement of Sulfur Oxides Emissions Power Research and Testing Organization " Energopomiar " Gliwice, Poland Contrary to the information spread by different firms and organizations, a technological process permitting sulphur oxides emission from large boilers to be effectively reduced has not been elaborated so far-*-. All the industrialized countries are carrying out studies aimed at the solution of this pertinent problem. A necessity of independent research being carried out even by the countries of lower economic potential arises from the fact that the economics of the process will depend on the whole complex of conditions such as the site selection and weather conditions, raw materials and costs applicable individually to each power plant. The experience gathered so far shows that the increase of nuclear power plant contributions to the total world balance of electrical energy production will not reach anticipated values within the nearest decades^. A lot of attention has been paid to the problem of SO2 emission in Poland, where bituminous coal is the basic fuel used in power generation. Since our own research program was initiated four years ago we have been devoting considerable means for this purpose. All of the research and experiments conducted in this field in Poland are coordinated by the Power Research and Testing Organization "Energo- pomiar" in Gliwice. Among the technologies recognized throughout the world as most suit- able for full scale application, the so-called "throw away" processes will be considered first (i.e. the method used by Combustion Ltd., dry additive method etc.^). This approach results from detailed cost analyses carried out for the processes designed as cost-returning as the size of the pilot plant increases. New conceptions of the basic combustion process are considered next. In these the flue gas is obtained without toxic sulphur compounds (advanced gas — turbine steam — power cycles; combustion in fluidized bed^) . In the third instance processes of flue gas desulphurization with the recovery of commercially valuable sulphur are considered. Final concern is for various processes for coal desulphurization. The purpose of this paper is to present the principal results of studies on the original Polish technology for the "throw away" category. This technology can be used intermittently as a means of intervention in case of particularly unfavorable weather conditions. Polish air quality standards specify that the maximum average daily concentration of SO2 in the atmospheric air should not exceed 0.35 mg/iri^, 271 and the maximum average concentration over a period of 20 minutes 0.90 mg/m^ The meteorological conditions leading to such concentrations occur in the climatic conditions of this country rather seldom and never over a period longer than 10% of the power plant annual operation time. The necessity to decrease the SO2 emission, in the periods of excessive emission rate, arises first of all from the toxic influence of this pollutant on vegeta- tion 5 . On the basis of the conclusions drawn from the references it may be expected that vegetation will be sufficiently protected if the occurence of concentrations, greater than the values specified by the standards can be prevented. From the economic point of view it is apparent that the process of intermittent SO2 limitation in the power plant must have low investment costs, as the installation is not operated on a continuous basis and the capital return period is consequently short. The operating costs of such an installation can be relatively high as they will not greatly affect the overall cost of electrical energy produc- tion, due to the short operating periods. To render its application technologically feasible the intermittent process must be as follows: 1. Flexible — short and easy start up and stopping 2. Reliable — little risk of maloperation 3. Should not result in major technological difficulties such as: circulating a large volume of solution or gas in the system; production of waste products — difficult to store; engaging additional staff, etc. Our intervention method meets all the requirements stated above. It is based on an introduction of ammonia into the flue gas and the emission of the reaction products together with the remaining components of the flue gas into the atmosphere. At the temperature and water vapor concentration conditions as well as acid anhydride concentrations occuring in power boiler flue gas, the formation of the reaction products in the form of crystals is not possible. The phenomenon of ammonium salt aerosol formation takes place at a certain distance from the stack outlet after the plume has been diluted with an appropriate amount of cold air. After lowering the temperature below the cyrstallization point a process of ammonium sulfite particle formation begins in the diluted plume. Particles of the order of 1/u size are formed. The water vapor present in the plume facilitates the oxidation of sulfite to sulfate which takes place particularly fast in a solution. Investigations carried out in many fields included: 1. The influence of ammonia flue gas neutralization products on animals. These experiments, conducted by a team of specialists from the Silesian Medical Academy, consisted of: a. introduction of the reaction products through the respiratory system of test animals (exposure to an atmosphere containing neutralization product aerosol) b. introduction with food 272 c. introduction by means of injections directly into viscera with a physiological salt solution. The results obtained so far indicate that a marked protective action of flue gas neutralization by ammonia has been observed in the animals subjected to tests. Table I presents the results of specialized experiments carried out on animals tested by inhalation (introduction of the agent to the body through the respiratory system) . Attempts to determine the mechanism of protective action have led to discovery of another advantageous effect i.e. the neutralization of nitro- gen oxides present in flue gas. Some of the studies conducted so far have been published — references °'''°; This year further tests are being carried out using real flue gas in one of the Polish power plants. 2. The influence of ammonia flue gas neutralization products on vegetation. The experiments- on the influence of ammonia flue gas neutralization products on selected kinds of vegetation were conducted by the Institute of Agriculture in Lublin and have included garden plot and test pot experi- ments. Table II illustrates the protective effect of SC>2 ammonia neutraliza- tion in case of rapseed and sunflower plants. The investigations conducted this year included exposure of vegetation to SO2 concentrations simulating as closely as possible real conditions. Constant background SO2 concentration value of 0.2 mg/m^ was maintained in the exposure chambers; apart from that the concentration was increased by 1 mg SC^/nW for eight hours a day. Only eight-hour peak values were subjected to neutralization. Table III shows the neutralization effect obtained for clover. 3. Study of the influence of ammonia flue gas neutralization products on the physio-chemical properties of selected soils. After the first successful experiments with chemically pure products of neutralization the investigations are going to be continued this year. The Environmental Protection Department of the Polish Academy of Sciences feels that it is justified to extend the research to the total balance of sulfur in the soil-plant-atmosphere system. 4. The influence of ammonia flue gas neutralization products on biological life in the waters. Studies of the influence of flue gas neutralization by ammonia on biological life in the waters were carried out using reaction products obtained from real flue gas. The reaction products of ammonia and real flue gas have had an effect similar to artifical fertilizers. In experiments conducted on fish appro- priate doses of ash with ammonium sulfite have displayed no toxic action 273 even after eight days of application. 5. The influence of ammonia flue gas neutralization products on the atmos- pheric corrosion processes. Unexpected results were obtained in testing the influence of ammonia neutralized flue gases on atmospheric corrosion, even in the case of copper alloys. Table IV illustrates the extent of the protection giving brass type M-60 as an example. Good results of all the preliminary experiments served as a basis for the design of a full scale experimental installation for two power sets of 260 MW total rating. The investigations carried out with the help of this installation were aimed at resolution of our doubts whether the remnants of fly ash particles passing through the electrostatic precipitator will not build up, gathering ammonium salts. Such a phenomenon might lead to considerable changes in the dust distribution in the vicinity of the power plant. Samples of dust contained in the plume were not different both for original flue gas and for the ammonia neutralized one. The measurements of the neutralization products spreading in the atmosphere made in different atmospheric conditions have shown that moist snow stimulates the greatest ammonium salt fall out. The maximum fall out assumed for continuous neutralization over a period of one month and unvarying wind direction would result in 20 kg of ammonium fertilizer per hectare. It is less than doses used in agriculture. The results described above were obtained in an installation neutral- izing flue gas from boilers using bituminuous coal of 2.5 to 3.5% sulfur content. Similar experiments were carried out in Turow power plant in order to corroborate the results of tests for boilers using lignite. Fuel used in this power plant contains only 0.5% of sulfur, but as the calcri-ic value of the lignite is low (2000 kcal/kg) the sulfur emission to the atmosphere is equal to about 1 t/hour per 200 MW set. The experimental installation permitted us to neutralize flue gas from a common stack for two power sets of 400 MW total rating. The longest period of neutralization run continuously was 11 days in weather conditions termed as "an autumn drizzle" . The good results obtained for this installation made it possible to plan the conceptual design of an experimental installation for an entire 2000 MW power plant. The problem to be solved, is what criteria should be applied to the start of intervention and its extent. There are two kinds of weather for which excessive SO2 concentrations may occur in the lower layers of the atmosphere: a. periods of little mobility of a large volume of air, with an inversion layer forming above the stack outlet level (a toxic cloud of S0 2 builds up over the power plant stack its base reaching ground level) . b. periods of considerable turbulence of the air layers near the ground occuring at relatively high wind velocities (whirls of poorly diluted flue gas "roll" on the ground) . Each of the types of weather described above will require different operation of the process. 274 Though the weather of the "a" type may be very dangerous for the biosphere it occurs rarely under our climatic conditions. The second type of weather occurs more often and the conditions created by it are respon- sible for the influence of S0 2 on vegetation in the neighborhood of indivi- dual sources of emission. The installation erected in Turow power plant will be equipped with a network of automatic SO2 analyzers capable of monitoring the concentrations existing in the power plant vicinity. A special meteorological station located near the power plant will conduct an appropriate measurement program including all the meteorological para- meters important for the distribution of pollutants in the boundary layers of the atmosphere. The experience gathered during this research program should provide data permitting us to determine the intervention programs for individual power plants with less cost. Our dry ammonia method which has been tested on a larger scale than other methods compares very well with these other methods from the economic point of view. Taking into consideration the advantages of loss prevention in the forests and perhaps some fertilizing effect in agriculture and comparing them with the costs of interventional method operation it may turn out that the final economic balance is favorable. References 1. Abatement of Sulfur Oxide Emissions From Stationary Combustion Sources; Washington D.C. 1970, National Research Council. 2. U.S. Atomic Energy Commission, Division of Industrial Participation "The Nuclear Industry — 1969", Washington, U.S. Government Printing Office, 1969. 3. Control of Sulfur Oxide Emissions by Lime — Based Scrubbing Process, R.E. Harrington — NAPCA, ECE Seminar on the Desulphurization of Fuels and Combustion Gases. Geneva — November 1970. 4. Capturing Sulfur with Calcined Dolomite, R. Graff, R. Pfeffer and A. Squires; Second International Clean Air Congress of the IUAPPA, Washington, December 1970. 5. R. Zahn: Untersuchungen ttber die Bedeutung kontinuierlicher und intermittierenden Schwef edlioxideinwirkung fur die Pf lanzenreaktion, Staub 23, 1963, 343-352. 6. S. Kosmider: Ocena metody wiazania SO2 gazowyra' amoniakiera w aspekcie toksykologicznym, Biul. Sluzby San.-Epid., 1970, 2, 179. 7. S. Kosmider: Ocena toksycznosci produktow powstalych w wyniku wiazania dwutlenku siarki gazowym amoniakiem, Biul. Sluzby San.- Epid., 1970, 3, 245. 275 8. Enzymatische und Saurebasen Gleichgewichtsstorungen nach experimenteller Schwefeldioxid Vergiftung sowie Schutzwirkung von Ammonxakdampfen, Int. Arch. f. Arbeitsmet., 1970, 26, 316 276 fl Eh > •H P ■P o P Oh C ■H en P •H ro a N •H ro H ro c M •H -P 3 3 Cn 0) C a; fl CN-P o CO ip, ro •H c 03 ra p u ro C •H ip c 03 •H 0) P H O 0, ro a ro X T3 CD P U -H to 03 - P -P 03 C P o <£> l> T3 1 a 3 = IT) H CTi -P -P CO = 1 CD U ro IP C g o C\) m CD 1 v£> i> •H P CN • , <£> Q g O r-» H 03 - P P 03 C CD in CD P CN a in T3 rH • 3 = CM i> -P -P CO = 1 CD CD U ^ rH CD CO c o ^D 03 o •H ^r in • • m a CN CN Q, CO. +1 o £ + 1 +1 co O m o in CO H >i 03 (N m H # a CO -p ro o, CTi H g iH +1 +| »£> ro -H g 00 r- + | CD C t g p fl rH O -P U 3 fl c ■H C P rH c ro CO to ih ro ro ■H fl u ro g fl 3 fl CO H p p H .H g p 1 -H & -P 3 T3 ro p p TS P g -P •p > p U3 •H fl ro co o a) •rl U -H X rH -H H £h jtI .w -.A (U M W TI A 277 Table II Protective influence of SO2 neutralization by ammonia on rapeseed and sunflower Type of Vegetation Crop in qrams interval of confi- dence for P = 0.05 Relative values so 2 S0 2 +NH 3 so 2 S0 2 +NH 3 Rapeseed Sunflower 26.88 11.85 22.41 8.96 28.81 12.56 3.30 1.62 100 10C 83.37 75.61 107.18 105.99 Table III Influence of SO2 neutralization by ammonia on clover No. Reference test S0 2 back- ground so 2 peak S0 2 +NH 3 1 Mean plant height /cm/ 2 Dry mass /g/ 3 Green mass /g/ 33.92 27.39 134.91 32.10 27.06 137.51 29.17 20.51 105.01 37.17 30.80 142.25 Table IV Corrosion of brass type M-60 in a chamber with SO2 and with S0 2 + NH3 Time of exposure Mean loss ; of weight Surface corrosion index V c g/m 3 day so 2 S0 2+ NH 3 so 2 SO2+NH3 274 521 825 969 0.0046 0.0061 0.0085 0.0085 0.0046 0.0051 0.0066 0.1775 0.124 0.1094 0.091 0.178 0.103 0.070 278 AIR-POLLUTION PREVENTION AND CONTROL IN ROMANIA — GENERAL ASPECTS OF THE PROBLEM By Matei Nicolau Engineer, National Council for Science and Technology Bucharest, Romania It is known that nowadays the intensive rate of industrialization, urbanization, farming mechanization and the growth of transportation is bringing about in all countries an intensive air pollution problem which every day becomes more serious and raises particularly intricate problems ' from many a point of view such as: technical, economic, juridical, meteor- ological, biological and social-sanitary. Air pollution effects can be reflected in the general health condition of the population, in the natural, biologic frame of the polluted area; in the service life of buildings; in plants, transportation means, and also in other material goods subjected to contaminants. To improve the protection of the environment in Romania, a number of important steps have been initiated in an attempt to provide an organized solution for the present or future problems raised by air pollution. Among these steps we may count the elaboration by the National Council for Science and Technology of a priority basic research program, the object of which is to devise new means and procedures for air pollution prevention and control so as to cope with the urgent character of the problem. The main goals of the program are: To maintain and improve the health condition of the population; To reduce the damage produced in the national economy as a consequence of air pollution by implementing the research carried out on plants, tools, devices, and air pollution supervision, prevention and control systems; To train specialized staff whose special task is to deal with problems related to air pollution prevention and control; To develop and update the technical and material basis of the scientific research work carried out to improve the man-environment rela- tionship; To develop and expand at an international level, technical and scientific cooperative efforts for solving problems related to clean air; and To inform and educate the population with a view of stimulating its participation in the general effort. The priority program of scientific research aims at air pollution pre- vention and control and is to be given life through well defined actions closely related to present and prospective needs of the Romanian economy. This program carries on scientific research work on air pollution and environmental protection initiated during the last years by a number of research institutes and specialized centers working in the field of chemical engineering, metallurgy, electrical engineering, and the building material, food, and consumer goods industries. This research has resulted in the 279 design and building of efficient plants, equipment, aggregates and facili- ties dedicated to air pollution supervision, prevention and control. The scientific research work included in the program is centered on problems of a technical, economic, juridical, meteorological and social- sanitary character. Among these problems, we mention: Cleaning of hot gases containing suspended particles; Cleaning of industrial sulphurous anhydride gases; Desulphuration of liquid and solid fuels; Improvement of processes applied for dry cooling of incandescent coke in ferrous metallurgical works; Smokeless charging of metallurgical coke furnaces; Cleaning of hydrogen sulphide from industrial gases; Fluorine trapping and recovery in super-phosphate and aluminium production works; Catalytic burning of residual gases generated by petrochemical refinery plants; Trapping and cleaning of residual gases generated by works producing carbon black; Cleaning of noxious gases evolved by technological processes applied for metal surface coating; Cleaning of odorant gases; Cleaning of gases evolved from lead and zinc producing processes and recovery of non-ferrous metals from these gases; Cleaning of gases discharged by motor-cars; Dust trapping in foundries, ore processing plants, coal prepara- tion plants, refractory and building material production factories, ore sintering plants, etc. ; Establishment of quality characteristics for the environment in various areas and working sites; Effects of contaminants on environment quality and permissible limits for their action; Establishment of air self -cleaning parameters; Improving understanding of turbulent diffusion of contaminant gases by the atmosphere; Recovery of useful substance from industrial residual gases; Study of noxious effects of contaminants on the natural biolo- gical environment; and Studies of the effects of environment pollution on the human organism. In addition to these missions of a scientific character, an important concern is also felt in Romania for the organizational and quality control aspects of the air pollution problem. Thus the big contaminant producers (i. e. industrial plants and aggre- gate works) have been required by the rules in force to revise their gas cleaning plants and their waste plants, and to improve their plants with a view to avoiding air pollution exceeding the limits adopted. Staff training and specialization in problems related to the atmos- pheric environment are to be taken care of within the priority research program already mentioned. Thus, staff training and specialization programs will include both postgraduate training courses organized within the frame of high technical institutes, and refresher courses held within specialized research organizations. 280 In parallel with the efforts for staff education and specialization, the organizational steps recommended for environment protection in Romania include important actions involving education, information and active and wide participation of the population to air-pollution control. Education of the population takes the form of training on general and town hygiene and on the bases of technical and sanitary education in the framework of secondary education. The education of the population in the field of air pollution protec- tion will be carried out in the people's universities, as well as through periodically organized lectures and symposia, particularly within large industries and urban centres. The laws in force on hygiene and public health have educational character and, as a consequence, the efforts displayed by our government for the protection of the atmospheric environment results in a wide parti- cipation of the population. The population of our countries is well informed of the causes and effects of air pollution and of the latest achievements of scientific and technological research carried out on the - supervision, prevention and control of environmental degradation, both in Romania and abroad. Radio and television broadcasts are always available to those respon- sible for public information about environmental protection. At compara- tively short time intervals, special programs are broadcast through these channels, describing the main technical, economic and sanitary aspects of our air pollution control program in the context of the intensive indus- trialization under way in our country. Moreover, the press devotes a large amount of space in the newspapers to problems related to environmental protection and, through a number of scientific and technical journals and wide circulation, the latest news in this field is widely disseminated. We feel that the strong actions now in full progress in our country directed toward air protection, favoured by a wide participation of the population and of an important number of central and local state, economic, scientific and public organizations, are in full accord with the goals of the U.N. which includes this problem among its most urgent concerns. At the same time, these actions set up the basis for wide cooperation with the technical, economic and scientific efforts of all countries concerned by this problem, the United States of America included. 281 BASIC CRITERIA OF THE NORMS FOR MAXIMUM ADMISSIBLE POLLUTANT CONCENTRATION IN THE ATMOSPHERE OF TOWN AREAS By M. Barnea Head of Laboratory Institute of Hygiene and Public Health Academy of Medical Sciences Bucharest, Romania It is known today, on theoretical and practical bases, that to obtain good results in the protection of the atmosphere and to avoid the dele- terious effects of pollution, it is necessary to apply quantification methods, useful for appraising the effects of pollution and the efficacy of the measures taken for controlling pollution. General concensus exists concerning the use of limits on pollutant levels in the atmosphere of town districts as a basis for pollution control. The complexity of the phenomena involved in air pollution is one of the main causes of the delay with which the norms of protection based upon maximum admissible concentrations are being drawn up, in spite of the importance attributed to this problem throughout the world. Another cause of delay is the absence of a unitary concept of the principles for establishing thresholds of damage. A generally accepted criterion, substantiating pollution control measures, is the pathologic effect upon humans and upon animal organisms in general. Numerous proofs of toxic risks have been made evident in the form of acute diseases and even of deaths, or by an increase in chronic morbidity. Local, regional and worldwide econologic hazards, that may have indi- rect implications upon the health of humanity, may likewise represent important reference points for the orientation of control methods. An instance of a mechanism of action of this kind is the hypothetical conse- quence of a change in the natural radiant regime and consequently in the earth's climate, with harmful effects upon human society in its entirety, caused by pollutants considered until lately as almost harmless — carbon dioxide and non-toxic dusts, in apparently anodyne concentrations but generalized throughout the atmospheric ocean. Another instance is the action of substances with deleterious properties, such as carcinogenic hydrocarbons, heavy metals, radioactive substances, etc. For the human society of today and of the future, the effects upon the biosphere may be of primordial importance, such as the degradation of artificial, lifeless structures, for instance that caused by corrosion, especially when they affect the fine mechanisms of complex automatic machines, computers, etc. Of all the effects of pollution, those that affect the health of mankind must be considered the most important. In most cases, on adopting the thresholds of action upon man as reference points of protection, a benefit is also incurred in other sectors. Mixed public health and economic considerations are sometimes taken into consideration in estab- 282 lishing norms of protection. The health criteria of pollutant norms and air purity indices, accepted in 1964 by the W.H.O. Committee of Experts (Technical Reports Series no. 271) is an oustanding guide in this connection. 1. The basic criteria of air purity indices are the tests accord- ing to which the order of magnitude of the effects of air pollution on man and his environment can be determined. 2. Air purity indices indicate the concentrations and duration of exposure corresponding to the specific effects that various degrees of air pollution may have on humanity, animals, plants and the general environment. 3. At the present level of our knowledge, air purity indices may be defined by four categories of concentrations, duration of exposure and corresponding effects. These four categories are characterized by limit values that may vary for a given pollutant in terms of the effect taken into consideration, the criteria applied, the nature of the other substances present and the meteorological factors, also taking account of the diversity of reactions in different groups of people. The participants to the W.H.O. Symposium agreed to define the four categories by the following levels: Level I . The concentration and duration of exposure are equal to or less than the values which, as far as we know, have no direct or indirect effect, including change in the reflexes or in the modification of protective reactions. Level II . The concentration and duration of exposure are equal to or greater than the values at which irritation to the sense organs, noxious effects upon the vegetation, reduced visibility or other unfavorable effects upon the environment, may be noted. Level III . The concentration and duration of exposure are equal to or greater than the values at which impairment or alteration of vital physiologic functions that risk production of chronic disease or premature "death, probably take place. Level IV . The concentration and duration of exposure are equal to or greater than the values at which an acute or chronic disease, or premature death would probably occur among vulnerable groups of the population. The W.H.O. Committee expressed the wish to establish without delay international indices of the purity of the air, on the basis of these principles . However, these levels recommended by the Committee at present, do not define an admissible limit. Rather, they emphasize air pollution by deleterious biologic substances that result from man's activity should be avoided as' much as possible. The fact that no precise criterion has been adopted by the Committee in its recommendations and that the introduction of norms of maximum admissible concentration into practice have encountered many difficulties and have differed from one country to another, shows that at present no readily applicable method exists for the drawing up of air protection norms. The generally accepted criterion, thatof acute or chronic disease, is not fully satisfactory from the viewpoint of hygiene, since a series of changes in the health status may develop before they manifest pathologic symptoms, which, once they have set in, may be irreversible. Correct pre- 283 vention implies evidence of preclinical changes, and no general consensus exists concerning them. The utility of certain indicators of preclinical alterations is also demonstrated by the high morbidity rate attributed to pollution by epidemiologic studies carried out in zones of moderate pollution. It is hard to confirm these effects experimentally because of the infinite difficulty of reproducing in animals the complex situation in which a popu- lation lives in a polluted area. The duration of the action upon humans cannot be realized with animals and the response of man is different from that of animals, etc. Moreover, in order to establish the threshold and mode of action of air pollutants a great number of experimental variants are necessary, involving single substances and mixtures, in combinations in which various aspects, linked to organic or environmental-dependent adjuvant factors, interfere. On putting into concrete form the norms of maximum admissible concen- trations, an important contribution would be to quantitatively correlate the results of epidemiologic studies with the concentration of pollutants in the air. On the basis of correlations heretofore established, it was possible to determine the role of mean concentrations over a long interval (one year or more) at particularly low values (for instance, non-toxic particles and mean sulfur dioxide concentrations of tenths of milligrams) . Such results were found in air basins with well known pollution, where morbidity from respiratory disease is high, as for instance in certain industrial regions in England and U.S.A. This has led the bodies respon- sible for drawing up protection norms to take epidemiologic criteria (well conceived, and applied in terms of long duration, medium concentrations) into consideration. This procedure must be complemented by, and be in agreement with, short duration concentration norms — 1 month, 1 day, 8 hours, 30 or even 5 minutes. As shown by Stern and other authors, a long duration medium concentration also includes larger concentrations, in a smaller and smaller proportion of cases. The norms of maximum admissible levels previously elaborated refer in most cases to short intervals of 24 hours and 30 minutes. Complete norms should keep account of a wide range of values, establishing the maximum admissible concentrations for all time intervals. For a single time interval the special properties of the respective substance must be borne in mind. For instance, with substances that act by an acute mechanism, such as most toxic irritants which have an effect upon the nervous system, short term norms should not be overlooked. For substances that act by accumulation, such as heavy metals, chronic effects and mean levels over a long term (a year or more) must be taken into consideration. It is recommended that mathematical methods be applied, at least for extrapolation. It appears pertinent that these methods may have to be adapted to the physiochemical properties of the respective substance. Countless variants are necessary to confront the experimental results with reality, and these could only be covered by broad international cooperation. A foremost impediment is the multiple standard conditions under which exper- imental investigations have to be carried out. A difficult question concerning which there is no general agreement is that of the threshold of noxious action. According to some workers this threshold is exceeded only when a lesion or signs of disease appear; according to others it is sufficient to note alteration of certain impor- tant functions, representing the preliminary phase of the lesion or of the 284 disease. Although the two opinions seem divergent, some of the results converge towards maximum admissible concentration values. Practice has shown that for the sake of safety it is necessary to adopt lower values of the norms. It seems more difficult to reach an agreement concerning sub- stances with an exceptionally low olfactory threshold, for which this pro- perty alone is considered a reference point for substantiating the norms of maximum admissible levels. This viewpoint has not been accepted by all authors. From our experiments, we find that, in order to establish threshold effects, it is useful to carry out complex investigations on the four categories of functions which have an important role in the reaction of the organism to air pollution: -metabolic (e.g. body weight curve and oxygen consumption); -neurologic (motor and optic chronaxie, conditioned reflexes, adaptometry and electroencephalography) ; -enzymologic (especially blood catalase and hepatic enzymes — transaminase, aldolase, succindehydrogenase) ; -immunologic (resistance to infection and antibody genesis) . In some cases it is necessary to investigate other systems as well, especially the blood (morphology of the white and red cells, proteinemia, etc.) . For many toxic substances, it is recommended that the loading of the body with the respective toxic substance or its metabolites be determined by biochemical, histochemical and other methods. For this type of inves- tigation, it is necessary to establish corporeal loading norms for the healthy subject; and here, too, there is no general agreement. As a rule, in order to establish the deleterious effects of experi- mental pollution at threshold and higher toxic doses, it is recommended that a complex set of investigations concerning general reactions on the one hand and specific responses on the other be carried out. The results should be interpreted complexly taking into account the several reactions at the same toxic level. The experimental models by means of which the deleterious effects of air pollution are studied are closer to reality when the combined effects of two or more toxic substances are investigated, and when the physical and biologic parameters of the experiment are varied. We obtain good results in our experiments by determining the separate and combined actions of the toxic metals CI + S0 2 ± Pb. Selection of the tests and interpretation of the changes produced are of paramount importance in establishing the standards of maximum admissible concentrations. The results of our experiments are interpreted in comparison to the behavior of controls, by calculating the statistically significant differences for as great a number of tests as possible. The results of one of a few positive tests (in terms of their importance) are considered insufficient to establish thresholds of deleterious effects or norms of maximum admissible levels. It is recommended that tests on animals be complemented by tests on humans, especially when the risk of threshold doses is minimal. However, the results of these investigations are only partial if we bear in mind the prolonged and complex action of pollutants in town districts. Therefore useful conclusions, closer to the actual facts, should be obtained by epidemiologic study of the complex statistical changes 285 brought about by pollution among the population constantly exposed to certain pollutants, under the concrete conditions of populated centers. For this purpose it is necessary to study under separate conditions the phenomena that interest us; especially to exclude toxicomania and occupational intox- ication as interfering factors and to select carefully the subjects exposed for a long time to atmospheric pollution. In establishing the norms of maximum admissible levels, it is obligatory that we determine air pollution systematically in the area where the population whose health status we are studying lives, and as mentioned previously, calculate the mean values over varied intervals of time. We also must use adequately chosen controls. In our epidemiologic investigations, in the absence of biologic norms for healthy subjects, we use as controls, results obtained in similar groups of people living in pollution-free areas. As the conditions required by such investigations are seldom found in the field, the results can only be considered as partial. However, con- clusions may be confirmed by the investigations other researchers working under similar or nearly similar conditions elsewhere. Particularly interesting in this connection are the reports and graphical representations drawn up by D.H.E.W. in the U.S.A. referring to sulphur oxides and other pollutants. Practice has shown that although the possibilities of substantiating maximum admissible air pollutant levels are reduced, it is necessary to develop and apply provisional legal norms, and to use as low values as possible. 286 THE ACTION OF ATMOSPHERIC DUST AND GAS POLLUTANTS ON INFECTIOUS PROCESSES By Hie Ardelean Professor, Corresponding Member of the Academy of the Socialist Republic of Romania Head of General Hygiene Chair Medicine and Pharmacy Institute Bucharest, Romania Investigations Concerning the Action of Dusts and Gases on Infections of the Respiratory Tract In studies concerning the effect of polluted air on infectious processes, increasing emphasis is laid on the important role played by pollutants in the increase of morbidity from respiratory infections. Foremost of all are the statistical investigations regarding the relation- ships between the incidence of chronic bronchitis and the level of air pollution. In this connection recent statistical studies have shown a marked rise in the incidence of chronic bronchitis and the frequency of acute attacks of the disease in the towns with polluted air, the correlation being established especially with sulphur products and dusts in the air. At present, air pollution with irritating substances is considered, next to smoking, one of the main etiologic factors in chronic obstructive bronchitis. Similarly, an increase was found in the frequency of acute infections of the respiratory tract. Douglas and Waller found a close relationship in children between deep respiratory infections and the level of air pollution. Curtis Dohan found an evident correlation between morbidity from respira- tory infections and the concentration of sulfur compounds in 8 towns in the United States, with various levels of pollution. Among the diseases which can be correlated to air pollution he mentions influenza and other viral respiratory diseases. In Romania the statistical investigations carried out show a corre- lation between the degree of air pollution in populated centers and the incidence of acute and chronic diseases of the respiratory tract. Our studies, started in 1960, have been carried out under experimental conditions, and have concerned the action of various dusts (silicon dioxide, coal and calcium carbonate) and gases (sulfur dioxide and chlorine) on infectious processes (pneumococcus and influenza virus) . The Action of Silicon Dioxide, Coal and Calcium Carbonate on Pneumococcal Infection The size of the silicon dioxide particles used in the experiment was 90.5% less than 5 /u; 6.5% between 5-10 /u; 2% — 10-20 /u; 1% over 20 /u; that of calcium carbonate 88% less than 5 /u; 7% — 5-10 /u; 2% — 10-20 /u; and 3% over 20 /u; that of coal particles was 73% less than 5 /u; 14% — 5-10 287 /u; 6% — 10-20 /u; and 7% over 20 /u. As the pathogenic agent was used a pneumococcal strain, type XIX. The dusts were mixed in 0.5 mg amounts together with different pneumococcus dilutions, and administered to mice by intraperitoneal, subcutaneous and nasal routes. Intraperitoneal administration of the silicon dioxide mixture gave a mortality rate of 61.5%, the coal mixture 61.5% and calcium carbonate 50.0%, as against a mortality rate of 44.9% in the control lot. Following subcutaneous inoculation, the mortality rate in the experi- mental lot receiving silicon dioxide was of 93.7%; in the lot with coal 89.6%; and in that with calcium carbonate 83.3%; as against 58.3% recorded in all the animals of the control lot. In the lots inoculated by the nasal route, a higher mortality rate was found in the lot receiving silicon dioxide, i.e. 31.1%, and in the lots with coal and calcium carbonate 33.9%, than in the control lot 21.4%. The anatomic lesions in the lungs of the mice sacrificed 10 days after inocu- lation were far more extensive and frequent that in the control lot. The Action of Dusts on Experimental Influenza Infection Influenza virus, strain PR8, together with the silicon dioxide, coal and calcium carbonate dusts, administered by the nasal route under the same conditions as pneumococcus gave a mortality rate of 80.5% in the group receiving coal, of 75% in that with silicon dioxide and of 73.6% in that with calcium carbonate, as compared to 45.8% in the control lot. No differences were noted between the extent and frequency of the lesions of influenza pneumonic type in the dead mice of the lots receiving the dusts tested and those of the control lot. However, there was a sharp difference between these lots and the mice sacrificed 12 days after inocu- lation. The lot receiving silicon dioxide exhibited pulmonary condensations in 55.5% of the cases, that receiving coal in 28.5%, and the lot with cal- cium carbonate 26.3%, as against 17.9% in the control lot. These results show that dusts, and especially silicon dioxide aggra- vate experimental influenza and result in prolonged forms of the disease. Lowered Resistance to Infection Due to Chronic Sulfur Dioxide Intoxication Mice were kept in a sulfur dioxide atmosphere for 6 hours a day, during 106 days. Average sulfur dioxide levels in the air circulating through the pollution chamber was of 16-28 mg/m^. After this period the animals received an infectious pneumococcus XIX dose my intranasal route. The pathologic process was influenced by the action of sulfur dioxide, the frequency of pulmonary condensations being higher and the tendency to lengthening of the infectious evolution more marked. The Action of Low Chlorine Concentrations on Experimental Influenza Infection Investigations were carried out concerning the action of chlorine on influenza in mice exposed for 21 days, during 7 hours a day in the intoxi- cation chamber, to a concentration of 4.0 mg of gaseous chlorine/m 3 of air. After the intoxication period the mice received an influenza virus PR8 suspension by the intranasal route. 288 The mortality rate in the intoxicated lot was of 42.6% as compared to 21.6% in the control lot. Similarly, the influenza pulmonary lesions in the animals sacrificed 12 days after inoculation were more frequent, i.e. 77.4% in the lot exposed to chlorine and 20.7% in the control lot. It may be concluded from the results of our experiments that pollutants influence the respiratory infectious process to various degrees in terms of the physiochemical characteristics of the dust or gas. Under the influence of these agents, morbidity from pneumococcal or influenza infec- tions increase in the experimental animals, producing a greater number of pneumonic lesions. Experimental Investigations on the Phagocytosis Capacity and Bactericidal Activity of Leukocytes in the Presence of Dust Pollutants Starting from the pathogenic mechanism of pneumoconiosis, and especially silicosis, in which fibrosis is the result of complex cellular and humoral reactions to the toxic action of dust, we attempt to develop an in vitro " method by means of which it would be possible to determine the toxicity of these physicochemical agents. The principle used was testing of the phagocytic activity of leukocytes. The phagocytic test, or microcinematography, consists in the injection of a dust suspension in the peritoneal cavity of an experimental animal, preferable a rat. Within a few hours the injection induces an afflux of mobile cells — leukocytes — that phagocytize the dust particles. At this time, collection from the peritoneal cavity content and examination of the vital preparation in the microscope, under accurately defined optical conditions, will reveal the influence of the dust on the behavior of the cell, especially the migrations and movements within the cytoplasm. It thus becomes possible to study the behavioral and structural changes that take place in the phagocyte. The general condition for applying the test is to use very small dust particles. Particles larger than 5 /u cause a special reaction, known as a "foreign body reaction", i.e. the large particles cannot be ingested by a single cell but only by several cells which cluster together forming a giant cell. This phenomenon is produced both by inocucous and by noxious dusts. Because of this, these tests should be carried out with dust particles measuring 3-5 /u. The dust phagocytosis test was applied by us in a more complex way, since we considered that the toxic action of dust particles on the cyto- plasm of polynuclear leukocytes — the main defense elements of the organism — may be established not only directly by measuring changes produced in the cell, but also indirectly by measuring the reaction potential of the phagocytic system, blood cells and plasma to microbes, after their prior contact with the dust particles. Otherwise stated, we tried to determine the phagocytic and bactericidal complimentary capacity of the blood after being subjected experimentally to the toxic effect of dusts. This method and technique, introduced by us, permits both a qualita- tive and a quantitative appraisal of the influence of dusts on the phago- cytic system. Human blood obtained by venous puncture, and from animals by cardiac puncture, is defibrinated by stirring, or prevented from coagulating by adding heparin. In order to raise the number of blood leukocytes up to 5,000, 10,000 or 20,000/mm3, pure leukocytic exudates are prepared in the 289 peritoneal cavity of the rabbit by twice injecting 150-200 ml normal saline within the cavity. After the second injection the peritoneal exudate is collected in a 1.5% sodium citrate solution. The concentration of the leukocytes is determined and then the mass of centrifuged leukocytes is added to the defibrinated blood and adjusted to the respective concentration per mm^ blood. The microbial suspension is prepared from young cultures in a fluid medium, washed by centrifugation and suspended in simple broth so as to obtain approximately 100 million microbes/ml. A o.l ml amount of the microorganism emulsion, in a dilution of 10~1 to 10~6 is distributed into each glass vial, together with 10 mg of dust. SiC>2 and C granulometry showed a dispersion of 95% below 5 /u. The dust was first put in contact with the phagocytic system, and after 30 minutes the microorganisms were added. The vials with the accurately measured ingredients are fixed in a rotating device, at 37°C. The phagocytic index and bactericidal activity were determined at 10 and 30 minutes, 2, 6 and 24 hours. The phagocytic index was calculated on the one hand, by determining how many of 100 leukocytes ingested microorganisms, and, on the other hand by counting the number of microorganisms ingested per 100 leukocytes. At the same time, the number of non-ingested microorganisms was counted in 10 microscopic fields and marked + up to +++, according to the number of 1-10 microorganisms outside the leukocytes in one field. The bactericidal index was calculated by the total number of colonies that developed in a blood gelose medium poured into dishes and inoculated with a standard bacteriological loop with a blood+leukocyte_dust_micro- organism. Here are some of the results obtained with SiC>2, C and calcium carbo- nate, using as control a normal saline solution and immune serum against by respective microorganism, in this instance pneumococcal antiserum. Results 1. Immune serum . Very intense phagocytosis, with rapid digestion of the pneumococci. Phagocytic index was 35% at 30 min. There were no non-phagocyted pneumococci. The bactericidal activity of the system was very marked: at 6 h, no pneumococcus cultivated from 1 mm^ blood. 2. Normal saline . High intensity of phagocytosis, with a phagocytic index of 35% but with prolonged digestion of the pneumococci as compared to the immune serum samples. Bactericidal activity of the leukocytes was of medium intensity: at 6 h, 50 pneumococci developed on 1 mm3 blood; and at 25 h, 100 pneumococci developed. 3. SiO ?. Phagocytosis of low intensity. Phagocytic index was 22% after 30 min. contact with SiC>2 dust and pneumococci, and remained low at 6 h. It increased to only 41% at 24 hours, when the non-phago- cyted pneumococci began to multiply. Bactericidal activity was close to but less than, that of the normal saline samples at 6 h. At 24 h the number of pneumococci increased to 11,000 per mm3 blood. These results show that silicon dioxide particles inhibit the phago- cytosis and bactericidal activity of leukocytes, without definite action upon the viability or multiplication of the pneumococci. 290 4. Coal . Coal particles produce a powerful phagocytic action, the phagocytic index at 30 min. being 44%, is still high at 6 hours, and attains 80% at 24 h. Outside the leukocytes at 24 h there were a large number of non-phagocyted leukocytes, whose number was of the order of dozens of pneumococci on the single microscopic field. Although the bactericidal activity of the leukocytes was not inhibited by the coal particles, owing to multiplication of the pneumococci in the system, there were a large number of live pneumococci — at 6 h 600 pneumococci being counted; and at 24 h 200,000/mm3 blood. Therefore, coal particles are considered inert and, with little effect upon the leukocytes, favor the multiplication of pneumococci. 5. Calcium carbonate has an effect similar to that of coal, the phagocytosis index of 30 min. being 32%, but not exceeding 50% at 24 h, so that a large number of pneumococci are found in the system. The leukocytes that ingest calcium carbonate crystals have a hyaline aspect and phagocyte pneumococci to a small extent. Leukocyte bactericidal* activity, appraisable at first, i.e. 500 microorganism cultivated at 6 h falls sharply at 24 h, the number of pneumococci reaching 1 million/ mm 3 blood. Calcium carbonate strongly favors the development of pneumococci. Conclusion The results obtained with this experimental model supply data that confirm the conclusions obtained in experiments on animals. Dust particles, even those considered as slightly toxic or inert, aggravate the infectious process. 291 AIR POLLUTION CONTROL ON THE WORKING PLATFORMS OF COAL CARBONIZATION PLANTS By Matei Nicolau, Engineer National Council for Science and Technology- Bucharest, Romania On the coal carbonization installations of siderurgical combines, three types of technological processes have been evidenced which cause air pollu- tion. These processes directly affect the working platforms of the coking batteries, as well as the surrounding zones. In decreasing order of their noxious potential, these technological processes are: Lateral charging of the coal blocks into the pyrogenation chambers of the coking batteries; Quenching the incandescent coke; and Tar removal from the raw coke gas collectors. Besides pollution generated by the above three technological processes, the coking battery working platforms are polluted also by other air pollu- tion sources, for instance during discharging the coke mass from the oven, or during transport of the incandescent coke, etc. The present paper contains some contributions to the problem of fighting air pollution on the working platforms of coking batteries, in connection with the above-mentioned three technological processes, causing pollution of the surrounding atmosphere. Technological Process of Charging the Coal Blocks into the Coking Battery Chambers The technological process of charging the coal block into the coking battery chambers may be performed either over the top of the coking bat- tery, or laterally, on the side of the charging machine. The technological coal charging process over the tope of the coking batteries is accomplished in "loose" charges, for which only high quality coking coal can be used. This charging operation of the coal into the coking oven may be per- formed without the generation of raw coke gas. Therefore this process is known as "smokeless charging of coal pyrogenation ovens." Smokeless charging of coking ovens is performed frequently with the aid of a charging machine, traveling on the top of the coking battery, and with the aid of raw coke gas collecting and purification installations, using various hydromechanical systems. Unlike the charging of the coking battery from the top, lateral charging of the coal pyrogenation chambers — common to many coking plants throughout the world — is achieved with the aid of compacted charges, while raw coke gas is generated right during the introduction of the coal block into the oven, through a degassing process of the coal in contact with the incandescent walls of the oven. 292 Evacuation of these gases from the oven during the coal block charging operation is achieved the natural way, both through vertical discharge flues provided in the roof of the coking battery, and as well through the inter- stices created between the coal block and the walls of the oven, which are about 1.2 — 1.5 mm wide between coal block and side walls, and about 4 — 5 mm wide between the upper face of the coal block and the roof of the pyrogena- tion chambers. These raw coke gases, with a pronounced cancer igeneious character flood the working space of the charging machine and the upper coking battery platform, creating--on the one side — extremely hard working conditions for the coking plant workers — and on the the other side—causing severe pollution of the atmosphere of the siderurgical combine, as well s.s of the entire environments outside the combine, up to a distance of 1 — 2 km. The main difficulty encountered by the smokeless lateral charging of the coal block into the coking chambers is primarily due to the fact that any mechanical equipment connected to the vertical flues for the evacuation of the raw coke gas, will create under-pressure operating conditions in the interstices between coal block and roof of the oven. This under-pressure condition facilitates the influx of an important amount of fresh air into the plant, which, when mixed in certain proportions with the raw coke gas, will cause an explosion hazard. However recent investigations in this field have revealed the possibil- ity of solving the lateral smokeless charging problem of coking batteries, but up to the present, no optimum solution, both from the point of view of air pollution control, as well as from the point of view of economic require- ments (minimum investments and low operating costs) , and of the possibility of integral recovery of the raw coke gas, has yet been elaborated. Nevertheless, among some of the solutions suggested for the smokeless lateral charging of coking batteries, the following solutions may be taken into consideration: Blowing the raw coke gas into an additional collector with the aid of a steam ejector; Blowing the raw coke gas into the regular collector, also with the aid of steam ejector; Blowing the raw coke gas into a neighboring oven, where the pyro- genation process is yet incomplete; Burning the raw coke gas in a vertical fire chamber, built in the shape of a Laval nozzle, where the raw coke gas is moved with the aid of a central steam jet under a pressure of 10 — 12 atms ; and Natural evacuation of the raw coke gas into the atmosphere through the aid of specially designed stacks placed on the top of each vertical flue on the upper coking battery platform. The Technological Process of Quenching the Incandescent Coke The second main problem deriving from the coal carboinzation technol- ogy, causing pollution of the coking battery working platforms, is the quenching of the incandescent coke. The quenching of the incandescent coke in a siderurgical plant presents two separate aspects: One connected with the pollution of the atmosphere; and An important economic aspect. Under the conditions of conventional coke quenching, the incandescent coke delivered from the coking batteries into trucks, is hauled to the 293 chilling tower, where the quenching operation takes place. The quenching operation is performed with the aid of phenol containing water resulting from technological processes in the chemical plant, through direct contact between coke and water. After cooling, the quenching water is collected in a pit, from which it is recirculated into the quenching installation. The quenched coke is transported to the drying platform from which it is taken to the sorting selection by means of belt conveyors, and then shipped to the various users (blast furnaces, steel plants, mineral agglom- eration plants, etc.). It is well known that 4 cubic meters of cooling water are required for the quenching of each ton of incandescent coke. During the cooling process of the coke, about 0.8 m^ of phenol con- taining water for each ton of coke goes into the atmosphere of the plant, as vapors. These phenol containing vapors posess cancerigeneous properties, and through their settling-down on the surface of the ground, they produce nox- ification of the coking plant environment, as well as of the entire sur- roundings of the mill. Moreover, during cold weather, these vapors impede visibility on the working site of the plant, which may cause traffic accidents within the area of the mill. On the other hand, through evaporation of residual phenol bearing water particles from the quenched coke, a foggy atmosphere is created around the coking batteries, particularly on the final coke cooling plat- form. These vapors on the final coke cooling platform, resulting from resid- ual particles of phenol bearing quenching water, pollute the atmosphere to a particularly high degree, reducing the visibility in the working area of the coke handling machine and in the zone of the railway track situated between the coking battery platform and the final cooling platform to zero. Besides these serious inconveniences, the pollution of the atmosphere in this area, through the noxious character of the cancerigeneous vapors emanated, represents a serious hazard to the health and life of the workers employed in the operation of the coking batteries. At the same time with the above social and sanitary inconveniences, the coke quenching process also presents a serious economic disadvantage because it facilitates dissipation into the atmosphere of the physical heat of the incandescent coke. Owing to all these disadvantages presented by the coke quenching method it appears necessary to realize a dry cooling method for incandescent metal- lurgical coke. The technological process of dry cooling incandescent coke eliminates air pollution and, as compared to the conventional coke quenching method, presents two important economic advantages, i.e.: The possibility of recovering the physical heat of the incandes- cent coke subjected to cooling; and Qualitative improvement of the cooled coke. Dry cooling of the coke is achieved with the aid of inert gases (as N 2 ,c0 2' etc -)' resulting from the combustion of a very small percentage of the incandescent coke charge placed in the cooling trough. 294 By shutting down the admission of air into the cooling trough, the com- bustion process is interrupted, while the remaining combustion gases, now inert, are recirculated in a closed circuit over the charge of incandescent coke in the trough- Thus they gradually take over the physical heat of the coke, delivering it in turn, in a heat exchanger, to the inert gas cooling agent, for instance water, which is transformed to superheated water, satu- rated or superheated steam. Through recovery of the physical heat of the incandescent coke, a min- imum amount of at least 400 kgs of steam per ton of cooled coke may be ob- tained. With regard to the improvement of the qualitative properties of the coke through dry cooling, it should be mentioned that the water content of the coke decreases while the heat output increases. Due to the slow cooling process of the coke, through dry cooling, the possibility of the formation of internal stresses in the coke is eliminated. Dry cooling of the coke results in a more uniform coke grain size and in a higher mechanical strength of the coke. Owing to the multiple economic and social-sanitary advantages pre- sented by the dry cooling method, as compared with conventional quenching methods, investigation of this new process has appeared necessary in recent years in the scientific research programs of specialized research institutes in the S.R. of Romania, with encouraging theoretical and practical results. The world over, the dry cooling of the coke is accomplished through the use of inert gases (N 2 , C0 2 , etc.), while the recovery of the physical heat of the incandescent coke is achieved by passing the gas which has flowed over the coke charge to be cooled, through a heat exchanger, through which a cooling agent, for instance water, is circulated. During recirculation of the hot inert gases through the heat exchanger system, particles of non-combustible mineral substances and coke particles entrained by the inert gas, settle down on the surfaces of the heat ex- changer thus impeding efficient heat transfer between the cooled agent (in- ert gas) and the heated agent (water) . Another disadvantage presented by known dry coke cooling methods, the rapid deterioration of the heat exchanger system and premature breakdown of the inert gas recirculation equipment is also due to dust particles entrained by the hot inert gas. Solutions, proposed in Romanian patents, eliminate the above disadvan- tages by first cleaning the hot inert gas before it enters the heat transfer system. The Technological Process of Tar Removal from the Raw Coke Gas Collectors The third air pollution problem of importance on the working platform zones of coking batteries consists of removing tars from the raw coke gas collectors. For the chemical and energetic utilization of the raw coke gas pro- duced by the coal pyrogenation process, these gases are collected with the aid of a collector placed on each coking battery. During the coal carbonization process, the raw coke gas generated con- tains, besides other components, water and tar vapors, which partially settle out in the collector as condensed matter. Moreover, these gases, while tra- versing the charge, entrain small size coke particles (under 15 mm in size), which together with the condensed tar acting as a binder form agglomerate 295 deposits (coke dust and tar) , called tar mass, which settle out in the raw gas collector. Repeated deposition of tar masses, without their routine removal, may- lead to the plugging of the raw coke gas collector, constituting an impor- tant problem in the operation of coal pyrogenation plants. At present, at some coking plants, the removal of tar masses deposited on the inner walls of the raw coke gas collector is achieved manually with the aid of steel bars introduced through the collector inspection holes. These inspection holes are provided on the upper side of the collector and are placed at intervals of about 1000 mm from each other. Owing to the fact that inside the raw coke gas collector there exists an overpressure (of about 6 — 12 mm water column) , during the removal of the tar mass from the inner walls of the collector, raw coke gas discharges through the inspection holes into the atmosphere, causing intense air pol- lution in this zone of activity. This problem has not yet found an optimum solution on a worldwide scale. The removal of tar masses from raw coke gas collectors has been at- tempted with the aid of ammonia-containing water under pressure- (20 — 25 atms) , but this procedure has not lead to the results anticipated, because under the usual operating conditions, a stable emulsion is formed between the tar and the ammonia-containing water. The components of this emulsion are very difficult to separate by conventional means (settling out, etc.). On the other hand, the process requires considerable energy which results in increased coking plant operating costs. Taking into account the inconvenience presented by the hydraulic ammo- nia-water method for removing tar masses from raw coke gas collectors, it is evident that for an optimum solution of this problem, other methods have to be found. Treatment of the problem through a purely thermal method, by adoption of a tar and tar mass removal procedure using steam jets, does not reveal positive prospects for solution of the problem, because of the following disadvantages : Owing to the thermal operating regime of the collector, at a temperature of below 95 C, the steam introduced will condense, thus the entire problem is reduced to the above-mentioned hydraulic method using ammonia containing water; and Owing to the overpressure created by the water vapors inside the collector, these vapors may penetrate into the coal charge to be carbonized, thus prejudicing the pyrogenation process. A sealed mechanical collector, tar cleaning and removing system cannot be considered because of the difficulty of cleaning such mechanical systems. Thus, taking into account the above considerations, an optimum instal- lation leading to the solution of the problem must fulfill the following conditions : It must achieve efficient cleaning of the tar masses and tars and their optimum removal from the raw coke gas collector, while maintaining perfect tightness of the entire system. It should use an auxiliary fluid medium, circulating through the collector, and which should be easily recoverable. It is to be mentioned that raw coke gas and "condensate", are circulating through the collector. This condensate contains tar, water and coke particles. The tar derives from condensed tar fumes contained in the raw coke gas while water comes 296 partially from the condensation of pyrogenation water and from the initial coal hydration water, and partially from the water used for cooling the gas. The installation must present complete operating safety. It should not compromise the coking process. It should require but minimum investments and operating costs. It should enable the automation of the entire tar mass cleaning and removal process from the collector. Owing to the particular social-sanitary and economic importance of this problem concerning removal of tar masses from the raw coke gas collec- tors in coal pyrogenation plants in siderurgical combines, the investigation in this country for an optimum solution of this problem constituted in recent years an important preoccupation for scientific research by our specialized institutes. Encouraging results have been obtained. BIBLIOGRAPHY Aurand, K. — Continuous determination of dust concentration in polluted air. In: Staub Reinhaltung der Luft, F.R. of Germany, nr. 10, Oct. 1970. Benforado, David — Combustion method applied to the solvent vapor emission control . In: Air Engineering, U.S.A., 10, nr. 9, Sep. 1968. Benforado, David — Economic side of heat recovery in case of smoke incinera- tion in direct flame systems. In: Air Engineering, 9, nr. 3, Mar. 1967. Bennet, K.W. — Prevention of air pollution by siderurgical plants. In: Iron Age, U.S.A., 202, nr. 21, Nov. 1968. Economic Commission for Europe: Special meeting on air pollu- tion, Feb. 10-14, 02. 1969. Hatin, L.E. — Industrial tests of smokeless charging coking batteries. In: Koks, Himiia nr. 4, Apr. 1964, U.S.S.R. The technical fight against dust in the siderurgical industry. Hot gas purification. Air pollution in the siderurgical industry. 297 OU. S. GOVERNMENT PRINTING OFFICE : 1971 481-326/72