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 9491 
 
 SEWAGE UflLIZAflOK 
 
 ^v U.R.BURKE 
 
Cornet! University Library 
 
 arV19490 
 
 A handbook of sewage utilization / 
 
 3 1924 031 263 464 
 
 nfin anv 
 
The original of tliis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924031263464 
 
A HANDBOOK 
 
 SEWAGE UTILIZATION. 
 
 BY 
 
 ULICK RALPH BURKE, Esq., 
 
 E A EEtST EE- AT-L4W. 
 
 LONDON: 
 E. & F. N. SPON, 48, CHAEING CKOSS. 
 
 NEW YORK: 
 446, BEOOME STEEET. 
 
 1872. 
 
President White 
 
 Libra 
 
 '.ry 
 
 - 'ViO 
 
 LONDON : PRIKTED nV W, CLOWES AND SON&, STAMFORD STREET AND CHAHIKG CROSS. 
 
INTRODUCTORY. 
 
 The question of Sewage Utilization, together with that of 
 the drainage of towns and the purification of our rivers and 
 water-courses, has been for some years past forcing itself 
 upon public attention. Numerous Eeports have been pre- 
 sented to Parliament, all setting forth the magnitude of the 
 evils of the present system, and representing the urgency of 
 immediate reform. As far back as the year 1858, a Com- 
 mission [S. U. C, 1857], of which Lord Essex was Chairman, 
 reported to this effect, and as yet little or nothing has been 
 done. There is no doubt that what has chiefly deterred 
 Local Boards, or other governing bodies in towns from taking 
 any action in the matter, has been the difficulty of finding 
 out the most satisfactory mode of practically dealing with 
 what everyone admits to be a gigantic difficulty. Most of 
 the systems of Sewage Utilization hitherto adopted iu many 
 of our towns have proved unremunerative as speculations ; 
 the success of others has been supposed to depend upon 
 certain special conditions, unattainable in other places ; and 
 some are known to have failed to accomplish the most 
 important part of their programme, namely, that of dealing 
 with the sewage matter in such a way as to render it per- 
 fectly innocuous, both during and after treatment. 
 
 On the whole, however, the most extraordinary ignorance 
 prevails on the subject. Many towns would gladly establish 
 works which would purify and utilize their sewage, even 
 were the operations carried on at a slight loss ; but they are 
 unwilling to undertake works of whose nature they know 
 
 a 2 
 
INTKODUCTOEY. 
 
 nothing, which may involve them in considerable and unknown 
 expenses, raise their rates, and possibly in the end fail to 
 bring about the result they desire. Even many well-educated 
 engineers know but little of the comparative merits of the 
 various systems that have been already tried, and conse- 
 quently of the peculiar fitness or unfitness of any particular 
 system for the town or district in which they may be 
 interested ; they consequently hesitate to give any decided 
 opinion or advice upon the subject. Local Boards are 
 naturally unwilling to act without seeing exactly " where 
 they are going," and in the end nothing is done. 
 
 We hope that between Mr. Stansfeld and Sir Charles 
 Adderley something may be done during this session of 
 Parliament which may render it easier for local authorities 
 to take action in this matter, while at the same time their 
 responsibilities as well as their privileges are enlarged. As 
 it is, according to the Eeport of the British Association pub- 
 lished in 1870, there is " only one town in England (Carlisle) 
 " which experienced no difficulty, present or prospective," in 
 the treatment of its sewage ! 
 
 An impartial review and comparison, therefore, of the 
 various systems that have been tried in England and on the 
 Continent for some years past may, it is hoped, be of use, not 
 only in directing attention to the subject, but in enabling 
 those who are interested in it, by considering the causes of 
 the success or failure of the various systems under different 
 circumstances, to determine what system or what modifica- 
 tion of any previous system may be best fitted for the 
 requirements and capabilities of their district. In recording 
 the good or evil fortune of the various experiments that have 
 been tried, this little book lays claim to no greater merits than 
 that of a compilation, and as such it is hoped it may be found 
 a useful one. A great portion of the information contained 
 in it has been collected from the Eeports presented to Parlia- 
 
INTEODUCTOEY. V 
 
 ment by various Commissions since tie year 1858, and the 
 sources of information will be found in all cases indicated 
 for purposes of reference, and especially for the assistance of 
 those who desire to study any particular branch of the subject 
 more fully than in a general abstract like the present. To a 
 certain extent, therefore, this handbook will be found to 
 be an epitome of most of what has already been written 
 upon the subject, and as such will, it is hoped, be appreci- 
 ated by those whose time is of value, and who desire to have an 
 opportunity of judging of the relative merits of the different 
 systems in a small compass. I took up the subject without 
 any prejudices or preconceived notions. I have no theory to 
 support, no set system to advocate, and whatever may be the 
 shortcomings of the work, and I know how many they are, 
 I can at least lay claim to having been animated through- 
 out with a spirit of perfect impartiality, which will, I trust, 
 be evident in the composition of the following pages, and 
 may recommend them to the mercy of the professional critics. 
 
 1, Kinq's Bench Walk, Temple, 
 February, 1872. 
 
( vi 
 
 LIST OF ABBEEVIATIONS USED IN THE COUESE 
 OF THIS WOEK. 
 
 1st Report of the Commission appointed to Inquire into 
 the best mode of distributing the Sewage of Towns, and 
 applying it to beneficial and profitable uses, 1858, referred 
 toas 1 S. V. C. 
 
 2nd ditto, ditto, 1861, re/erred «o (M 2 S. IT. C. 
 
 3rd ditto, ditto, 1865, re/erred to as 3 S. U. C. 
 
 1st Report of the Commissioners appointed in 1868 to 
 inquire into the best means of preventing the Pollution 
 of Rivers, 1870, referred to as 1 B. F. C. 
 
 2nd ditto, ditto, 1870, re/err«ti to as 2 E. P. C. 
 
 Report presented to the Tottenham Local Board of Health, 
 by P. P. Marshall, Esq., C.E., and others, 1871, referred 
 toas Tott. Eep. 
 
CONTENTS. 
 
 PAGE 
 
 Inteoduotoey iii-v 
 
 List of Abbkeyiations i .. .. vi 
 
 I. Evils of the Present System of Sewage Tkeatment . 1 
 
 Pollution of Water 2-8 
 
 Waste of Manure 9 
 
 II. Eemedies 9 
 
 Privy and A sh-pit 10-11 
 
 Eureka System 12 
 
 Milan „ 12 
 
 Goux's „ 13 
 
 Moule's „ 13-16 
 
 III. Teeatment op Sewage by Chemical Means .. ..17 
 
 Experiments with. Lime .. .. 18 
 
 „ „ Lime and OMoride of Iron 19 
 
 „ „ Sulphate of Ammonia 19 
 
 Holden's Process .. 19 
 
 Sulphate of Alumina 20 
 
 Persalts of Iron 20 
 
 Blyth's Process .. •■ 20 
 
 Lenfs „ •• 20 
 
 Phosphate,, •• 22 
 
 ABC , 25 
 
 General Scotf s Process 30 
 
 mile's „ 30 
 
 Filtration 30 
 
 IV. Ieeisation •• 33 
 
 Croydon Sewage Farm 42-48 
 
 Appendix I. — List of Places, &c 49 
 
 „ II. — Smoke Drainage 50 
 
 „ III. — Mr. Bazalgette's Scheme 51 
 
 „ IV. — ^Law relating to Sewage Utilization 58 
 
 „ v.— Hille's Process 55 
 
 Ikdex 57 
 
A HANDBOOK 
 
 OF 
 
 SEWAGE UTILIZATION, 
 
 I.— TEEATMENT OF SEWAGE. 
 
 Although the scope of this book is strictly confined to the 
 treatment of sewage with a view to its deodorization and 
 utilization, it may be as well, before reviewing the various 
 modes of treatment which have been hitherto suggested as 
 remedies for the existing evil, to devote a few pages to a 
 consideration of the evil itself. According to the old Spanish 
 proverb, " To understand the disease is haK the cure." The 
 evil of vrhich we have to speak is of two kinds : positive and 
 negative. The one is the imperfect and dangerous manner in 
 which the drainage of our towns is removed, entailing the 
 pollution of our rivers, the destruction of fish, the defilement 
 of water for domestic, and in many cases even for manu- 
 facturing, purposes, and the contamination of both air and 
 water with a deadly poison, to which numbers of our popula- 
 tion annually fall victims. The other is the systematic waste 
 on a gigantic scale of a valuable manure. 
 
 These two evils are necessarily and intimately connected, 
 for the sewage which is so deadly in a watercourse or a cess- 
 pool, when properly distributed upon land, becomes as 
 valuable as a manure as it was previously noxious as a poison. 
 According to the late Lord Palmerston, "Dirt is a useful 
 thing, at present put in the wrong place." The most perfect 
 
i! TREATMENT OF SEWAGE. 
 
 system of sewage treatment therefore is ttat whicli leaves tlie 
 smallest amount of filth where it should not be, and conveys 
 the largest amount to where it should. 
 
 The most noxious as it is the most common effect of our 
 present system of dealing with the drainage of towns is un- 
 doubtedly the pollution of rivers, wells, and watercourses. 
 
 What account, say the Eoyal Commissioners of 1868, do 
 the various municipal bodies give of the state of the stream 
 as it comes to them ? They all complain that the water is 
 polluted by sewage .... that it is most offensive to the 
 sight and smell ; that it is unfit for use ; that even when used 
 for steam-engines it clogs up the boilers, and is injurious to the 
 machinery .... [1 JB. P. C, p. 12], Again .... when 
 taking samples at Throstlenest Weir, below Manchester, say 
 the Eoyal Commissioners of 1868, we saw the whole water of 
 the Eiver Irwell, then 46 yards wide, caked over with a thick 
 scum of dirty froth, looking like a solid sooty-crusted sub- 
 stance. Through this scum, here and there, at intervals of 
 six and eight yards, heavy bursts of bubbles were continually 
 breaking, evidently rising from the muddy bottom ; and 
 wherever a yard or two of the scum was cleared away, the 
 whole surface was seen simmering and sparkling with a con- 
 tinual effervescence of smaller bubbles rising from the various 
 depths in the midst of the water, showing that the whole 
 river was fermenting and generating gas. The air was filled 
 with the stench of this gaseous emanation many yards away. 
 The temperature of the water was 76° Fahr., and that of the 
 air 54°. [1 B. P. C, p. 16 in note. See also on this subject 
 2 S. U. C, pp. 11-13, and note.] It is not pleasant to know 
 that the water of the Thames is contaminated with the putre- 
 fying sewage of no less than 880,000 persons before it 
 reaches the spot whence our water companies draw the water 
 for the use of the metropolis ; nor to find on examination 
 that this water contains a larger amount of impurity derived 
 
TREATMENT OF SEWAGE. 
 
 from feecal matter than filtered sewage. [Tott. Bep., p. 57 ; 
 1 B. P. a, p. 66.] 
 
 Memorials and petitions to Her Majesty on the subject of 
 river pollution from Birmingham, Huddersfield, Nottingham, 
 Eotherham, Sheffield and York, will be found among the 
 Parliamentary papers for 1865 (ordered to be printed 6th 
 March — Lord Eobert Montagu). [See also on river pollution 
 by sewage generally, 2 S. JJ. 0., pp. 11-13, and notes.] 
 
 The amount of this pollution is almost incredible, and 
 will startle those who have not yet studied the statistics. An 
 analysis of the river Cornhrooh just before its junction with 
 the Irwell, ia June, 1868, gave the following results. In 
 100,000 parts of the water in the river, there were : — Total 
 solid matters in solution, 142-90; organic carbon, 4 '209; 
 organic nitrogen, • 243 ; anunonia, ■ 852 ; total combined 
 nitrogen, -994; nitrogenous nitrates and nitrites, -049; 
 chlorine, 38 • 97 ; salts of lime and magnesia, considered as 
 " hardness," 67 ■ 70 ; matter in suspension, 64 • 40. The most 
 injurious constituents of this water are, of course, the organic 
 carbon and the organic nitrogen, inasmuch as they serve as a 
 measure of the animal or vegetable matter vdth which the 
 water is polluted. A comparison of this with the composition 
 of the Mersey water near its source may be instructive. Total 
 solid matter in solution, 7 • 62 ; 0'° carbon, • 222 ; 0'° nitrogen, 
 ; ammonia, • 002 ; total combined nitrogen, ■ 023 ; chlorine, 
 • 94 ; hardness, 5 • 02 ; suspended matter, 0. The " hardness," 
 which in this latter case represents more than one-third of the 
 entire polluting matter [1 B. P. C, 15], is in no way injurious 
 to life. [See 1 B. P. C, 16, note.] 
 
 Although there can be no possible doubt as to the deleterious 
 effects of water that has been contaminated with sewage, it is 
 exceedingly difficult to obtain any exact chemical details upon 
 the subject. Thus Dr. E. P. Thome, .... examining into 
 the causes of an outbreak of typhoid fever in 1867, in the 
 
 B 2 
 
4 TREATMENT OF SEWAGE. 
 
 village of Terling, reports [Tenth Beport of Medical Officer of 
 Privy Council, 1867], that the outbreak was caused by the 
 drinking of water from certain wells ; chemical analysis did 
 not discover any noxious svhstance in the water, but the ana- 
 lytical results gave for three of the wells a previous sewage or 
 animal contamination as follows : — 
 
 "Well 1. — Previous sewage or aalmal contamination in 
 
 100,000 parts of water 24,850 
 
 Well 2.— Ditto 9,160 
 
 Pump.— Ditto 10,980 
 
 This is an amount of pollution hardly conceivable, being in 
 the case of well No. 1 nearly one quarter of the entire volume 
 .of water. Again, at Guildford, in 1867, in consequence of an 
 /^Ifutbreak of typhoid fever, Dr. Buchanan went down to make 
 investigation as to the causes, and turned his attention to a 
 ; new well which had for a short time supplied over three 
 hundred houses, many of which were visited by the epidemic. 
 It was found that a sewer ran within 10 feet of the well, and 
 that the sewage leaked through the joints of the brickwork 
 and saturated the soil just above the spring which supplied 
 the well. The water was afterwards analyzed, and although 
 no ingredient was found that could be pronounced noxious, 
 the results showed that each 100,000 lbs. of it had been 
 previously polluted with a quantity of animal matter equiva- 
 lent to that found in 7330 lbs. of average London sewage. 
 [1 B. P. G., 114. See also on this subject, Boyal Commission 
 on Water Supply, 1869 ; Evidence of Mr. Simon, Minutes of 
 Evidence, p. 167; and that of Drs. E. Parkes, Farr, Lethehy, 
 Brodie, Frankland, and other celebrated analysts. Beport, 
 pp. 73-94.] 
 
 As the evidence of these gentlemen may be somewhat diffi- 
 cult to be understood by those who are not practical chemists, 
 especially as to how water, in which no present impurity is 
 
TREATMENT OF SEWAGE. 5 
 
 to be found, may yet be pronounced to have been previously 
 contaminated with so much sewage, we will say a few words 
 in explanation of this branch of the subject, and refer such 
 of our readers as desire to find a fuller expose, at once popu- 
 lar and practical, to Professor Eoscoe's ' Progress of Sanitary 
 Science (1871),' from which we quote the following : — 
 
 " Tou will understand," we read [at page 127] " that the 
 danger lies in the water being impregnated with animal de- 
 composing matter, and with sewage matter generally. . . 
 Although no chemist can tell whether any particular water 
 contains the typhoid poison, yet he is able to tell the dif- 
 ference between pure water and a water which contains 
 animal impurity, for when the decomposition of an animal 
 body occurs, the nitrogenous portions which are thrown off, 
 that is the liquid and the solid products, get into the sewers ; 
 and if we can find in water a large quantity of this nitro- 
 genous animal matter, we may be certain that that water is 
 not fit to drink 
 
 " By a chemical analysis of water we can at once detect, 
 by the organic or albuminous nitrogen, whether it still con- 
 tains animal impurity, and by the ammonia and nitric acid 
 whether the water has heen polluted by animal matter which 
 has since been destroyed, or by the absence of excessive 
 quantities of these nitrogenous bodies, whether the water has 
 never been in contact with animal matter. It is thus possible 
 to calculate by a very simple process how much sewage has 
 come into such a water." 
 
 As to the mode of detecting impurities by the permanganate 
 of potash, see Boscoe, p. 131 ; but this test is a rough one at 
 best, and in many cases fallacious. 
 
 " There is still another means which chemists have of tell- 
 ing whether water is pure, and that is by the presence of 
 common salt. Pure spring-water ought to contain very little 
 common salt; but water which contains the infiltrations of 
 
6 TKEATMENT OF SEWAGE. 
 
 sewage brings in with it a large quantity of common salt 
 derived from the urine. Any water which contains more 
 than one part of common salt in 100,000 is almost sure to 
 have that salt brought in by sewage, and will therefore be 
 impure. This does not apply of course to water flowing 
 through salt districts." 
 
 As regards this branch of the subject, which, in the words 
 of the Eoyal Commission on Water Supply, " is beset with 
 difBculties," we cannot do better than quote the conclusions 
 to be found on pp. 116, 117 of the 1 E. P. C. :— 
 
 " 1. There is at certain times, in human excreta, some 
 material capable of producing disease of a very fatal charac- 
 ter in the human subject. 2. That this morbific matter can 
 be detected only by its specific action upon the human sub- 
 ject, and cannot be distinguished either by chemical or 
 microscopic analysis, even in the concentrated excreta, 
 much less in water mixed with the excreta. 3. That inas- 
 much as the organic matters of sewage are oxidized and 
 destroyed with extreme slowness in running water, there is 
 great probability that the morbific matter will escape destruc- 
 tion, and be conveyed to great distances in rivers and streams. 
 4. That owing to the rapid oxidation and destruction of the 
 organic matters of sewage during filtration through porous 
 soils, the passage of this morbific matter into deep wells care- 
 fully preserved from the admission of surface water is but 
 little to be feared." 
 
 But however difficult it may be to trace the existence of 
 morbific matter in water, there can be no possible doubt of 
 the deadly influence of water that has been contaminated by 
 sewage, on health. There is no need of argument upon this 
 point, and instances might be endlessly multiplied; the 
 inquirer is, however, referred to some very interesting sta- 
 tistics furnished by Dr. Farr in a letter to the Eegistrar- 
 General (printed in the quarterly return of the births, mar- 
 
TREATMENT OF SEWAGE. 7 
 
 riages, and deaths for the quarter ending 31st December, 
 1854), as to the cholera epidemic in 1849, giving details as to 
 the respective number of deaths in houses supplied by the 
 various water companies both in 1849 and in 1854. 
 
 With regard to the influence of the contamination of water 
 by sewage on health generally, see 2 S. U. C, Appendices 
 2. 3. 4. 5., and Professor Eoscoe's Progress of Sanitary 
 Science, pp. 123-8. Finally we ,give the suggestions of the 
 E. P. C. as to what is to be deemed pollution [1 B. P. C, 130]. 
 
 (a) Any liquid containing in suspension more than 3 parts 
 by weight of dry mineral matter, or 1 part by weight of 
 dry organic matter, in 100,000 parts by weight of the liquid. 
 
 (&) Any liquid containing in solution more than 2 parts 
 by weight of organic carbon, or 8 parts by weight of organic 
 nitrogen, in 100,000 parts by weight. 
 
 (c) Any liquid which shall exhibit by daylight a distinct 
 colour when a stratum of it one inch deep is placed on a 
 white porcelain or earthenware vessel. 
 
 {d) Any liquid which contains in solution in 100,000 parts 
 by weight more than 2 parts by weight of any metal, except 
 calcium, magnesium, potassium, and sodium. 
 
 (e) Any liquid which in 100,000 parts by weight contains, 
 whether in solution or in suspension, in chemical combination 
 or otherwise, more than '05 part by weight of metallic 
 arsenic. 
 
 (/) Any liquid which after acidification in the sulphuric 
 acid contains in 100,000 parts by weight, more than 1 part by 
 weight of free chlorine. 
 
 (g-) Any liquid which contains in 100,000 parts by weight 
 more than 1 part by weight of sulphur, in the condition either 
 of sulphuretted hydrogen or of a soluble sulphuret. 
 
 {h) Ajxj liquid possessing an acidity greater than that 
 which is produced by adding 2 parts by •n'eight of real 
 muriatic acid to 1000 parts by weight of distilled water. 
 
8 TEEATMENT OF SEWAGE. 
 
 (i) Any liquid possessing an alkalinity greater than ttat 
 produced by adding 1 part by weight of dry caustic soda to 
 1000 parts by weight of distilled water [1 B. P. C, p. 130]. 
 
 It has frequently been alleged that the natural flow of a 
 river, however largely impregnated with sewage matter, would 
 rapidly purify the volume of water by oxidation. It was 
 asserted [Report of Boyal Commission on Water Supply, 
 p. Ixxix.] that if sewage were mixed with twenty times its 
 volume of river water, the organic matter which it contains 
 will be oxidized and completely disappear while the river 
 is flowing a dozen miles or so. Experiment has, however, 
 demonstrated the fallacy of this vague assertion, and wo 
 find that of sewage matter mixed with twenty times its 
 volume of water, less than two-thirds would be destroyed 
 by oxidation in a flow of 168 miles at a rate of one mile an 
 hour [1 B. P. G., 21]. It is evident therefore that there is 
 no river in the United Kingdom long enough to eifect the 
 destruction of sewage by oxidation. 
 
 The destruction of the fish forms a very important con- 
 sideration in this sewage pollution of rivers, and especially 
 in Scotland and Ireland : when the fisheries represent a pro- 
 perty of large annual value to all classes of the community, 
 it is of the highest importance as population increases that 
 proper preventive measures be adopted. It is most encourag- 
 ing to learn that even where the fish have been entirely 
 banished by the pollution of the water, yet when the stream 
 has been purified by the adoption of an improved system of 
 sewage removal, the fish retiirn to their old haunts. This 
 happy result has occurred, among other places, at Leicester 
 [1 S. U. C, p. llj. It may be remarked in this place that it 
 appears to be the decomposed matter which proves so fatal to 
 the fish ; the fresh sewage, except in very hot weather, being 
 beneficial rather than injurious [2 ;S'. U. C, p II, note]. 
 
 With regard to the second branch of the evil, the waste of 
 
EEMEDIES. » 
 
 a great quantity of valuable manure, let us consider for a 
 moment how much the fertility of land depends upon the 
 amount of live stock that is kept upon it. Their excrement 
 forms, indeed, one of the most valuable sources of the farmer's 
 profit; and yet although one-third of the live stock of England 
 is mankind, human excrement is turned to no valuable 
 account. This will seem the more incredible when we con- 
 sider that as a consequence of the superior richness of the 
 food of man to that of cattle, his excrement is in every way 
 more valuable as a manure than that of any other animal. 
 Yet, notwithstanding this, we learn [1 B,. P. C, 72] that the 
 excrement of a sheep is worth at least five shillings a year to 
 the farmer, while the annual value of the excrement of a man 
 is worth (in South Lancashire) something less than fourpence 
 halfpenny ! The annual loss to the country from our 
 wanton waste of human manure amounts to many millions 
 sterling; and while we are compelled to import guano and 
 other manures from distant countries at great expense, we 
 allow our own valuable human manure not only to go to 
 waste, but to pollute our streams and spread deadly diseases 
 over the country. We should copy the Chinese in such 
 matters. A good account of their mode of treating the ex- 
 crement would be a most interesting contribution to our 
 Sanitary literature : a few words may be found on the subject 
 in Oliphant's ' China,' p. 118. 
 
 11.— EEMEDIES. 
 
 The few facts that we have gathered together with regard 
 to the evils attendant upon the present system of treating our 
 town sewage must have been sufficient to convince anyone 
 of the urgent need for reform in the matter. Although we 
 have taken a most cursory glance at the subject, we have 
 
10 KEMEDIES. 
 
 endeavoured to give such statistics and references as may- 
 direct tte mind of tlie inquirer to the nature and differences 
 of tlie various forms of evil vphich have to be guarded against, 
 so that he may be able to consider with advantage the various 
 remedial schemes which it is now our purpose to lay before 
 him. 
 
 Of these schemes there are two great classes, of which the 
 first proposes to go to the very root of the evil, and prevent 
 the sewage from getting into the drains at all ; and the second, 
 to direct, deodorize, and utilize it when it has got there. Of 
 the first class, the common privy and ash-pit system is the 
 commonest example. There are not wanting advocates even 
 at the present day for this well-known nuisance, especially 
 in Manchester, where it has been preferred, most unfortunately 
 as we think, to the water-closet [see also Birmingham Report, 
 1871]. The fallacy of the privy as a preventive system is 
 sufficiently evident from a comparison of the analysis of the 
 sewage flowing through the drains of a town like Manchester 
 and Salford, where the proportion of privies to water-closets 
 is about six to one, with that of London, where the water- 
 closet is universally adopted. These statistics may be found 
 in full on pp. 26-29 of the 1st Eep. of the E. P. C, 1870. 
 We will at present content ourselves with remarking that 
 as the " middens " are usually in some way connected with 
 the sewers, a considerable proportion even of solid excre- 
 ment, partly in solution and partly in suspension, finds 
 its way into the sewerage system. Indeed the figures show 
 a very slight diminution of the strength of the sewage of 
 a " midden " town, although the volume is somewhat less 
 in about the proportion of 1066 to 1154; the cause of 
 this difference in volume being obviously to be sought for 
 in the increased quantity of water needed under the water- 
 closet system. 
 
 The very slight difference in the volume and strength of 
 
REMEDIES. 11 
 
 the liquid sewage in "privy" towns and "water-closet" towns 
 is somewhat surprising, and is certainly an additional argu- 
 ment in favour of the water-closet system. [See also 1 B. P. C, 
 p. 30, where it is stated that the case is not substantially dif- 
 ferent when the earth-closet is substituted for the midden.] 
 But the failure in a financial point of view of the privy, and 
 the numerous ingenious modifications of it that have been 
 hitherto tried, is to be attributed to the fact that they are 
 only able to deal with the solid matter — the least injurious and 
 the least valuable part of the excreta [1 ij. P. C, 48], while 
 the greater part of the urine — so rich in ammonia — and the 
 whole of the fluid refuse from the kitchen and house generally, 
 is passed direct into the sewer. It is evident therefore that 
 by all these systems a great quantity of dangerous polluting 
 matter is suffered to flow into the sewers, not much decreased 
 either in volume or polluting power from ordinary raw 
 sewage; while that portion which is intercepted is deprived 
 of a great portion of its most valuable constituents, consi- 
 dered as a manure. Under the old-fashioned privy and cess- 
 pool system, an intolerable and dangerous nuisance is created 
 by the accumulation of sewage filth within a few yards of the 
 dwellings of the people ; and the noxious emanations con- 
 sequent upon every removal of the accumulations are often 
 the cause of various forms of disease. And this is the less 
 to be wondered at when we learn that in many instances the 
 privy refuse can only be removed by being carried into the 
 street from the back door to the front, through the very room 
 in which a large family is crowded at the time. This deadly 
 nuisance at least is guarded against in Moule's, Goux's, and 
 the Eureka system, which are all improvements upon the 
 privy. There is no doubt that some of these systems, or 
 modifications of them, may be introduced with advantage into 
 large country-houses, public institutions, or small villages, 
 and we will say a few words upon them before leaving this 
 
12 REMEDIES. 
 
 branch of the subject. Those who wish to enter more fully 
 into the question we have just been discussing will find an 
 elaborate comparison between the privy and water-closet 
 systems on pp. 23-30 of the Eeport of the E. P. C. (1870). 
 
 In the Eureka system, which was tried at Hyde, near 
 Manchester, boxes containing a small amount of deodorizing 
 mixture were fitted in at the back of every privy, and as 
 they became full, were exchanged for empty ones, after a 
 certain number of days, according to the number of persons 
 making use of the closet. The boxes when removed were 
 covered with closely-fitting lids, and carried away in covered 
 vans to the manufactory. Here the rags were first removed 
 and sold to the paper-makers. More disinfectant was then 
 added, and the matter concentrated by distillation, the dis- 
 tilled water being sold to the dyers and bleachers. The 
 residue thus thickened was then mixed with coal ashes, which 
 had previously been collected in the houses of the district 
 and finely ground, and was ready for distribution as a manure. 
 Messrs. Lawes and Gilbert, however, found by an analysis 
 that it contained scarcely two per cent, of ammonia, and would 
 obviously therefore not be worth more than its carriage beyond 
 a few miles. [See Notes on the Composition, Value, and TJtilizar- 
 lion of Town Sewage, reprinted from the Journal of the Chemical 
 Society, 1869. Sarrison.] 
 
 The great objection, however, to the Eureka system as con- 
 ducted at Hyde, was the proximity of the manufactory to the 
 town. The mode of collection of the sewage was unobjec- 
 tionable, but the works themselves were considered by many 
 to be a nuisance, and for this reason, as well as the weakness 
 of the manure manufactured, the system was abandoned at 
 Hyde. [See 1 B. P. C, 50, 51.] 
 
 The system in operation at Milan (a city of some 200,000 
 inhabitants), advocated by Mr. Gilbert Child [see ' Times ' 
 newspaper, August 29, 1867, January 2, 1868, and November 20, 
 
REMEDIES. 13 
 
 1871], consists in the collection of all the house sewage in 
 cesspools, which are frequently emptied by means of an iron 
 barrel from which the air has been exhausted, and which 
 sucks up aU the sewage through a hose without the carrying, 
 and necessary odour resulting from the ordinary mode of 
 emptying cesspools. The sewage is afterwards deodorized 
 and sold to the neighbouring farmers. [See further as to the 
 Milan system and generally as to those pursued in North 
 Italy, including the Lombard Irrigation, 1 S. U. C, 38-53.] 
 
 Gouxs System is similar in principle to the Eureka, but 
 the final treatment is somewhat different ; the manure manu- 
 factured by this process is also feeble, but inoffensive, and 
 has been adopted to a certain extent at Eoohdale. [See Report 
 of the Sanitary Committee of the Town Oovmcil of B,ochdalei\ 
 
 Of all the modifications of the privy, the best that has as 
 yet been invented is no doubt Moule's. In this system a 
 quantity of common dry eaxth is placed above the closet, 
 and after use a certain amount, about 1^ lb., of this earth is, 
 by a simple and ingenious mechanical contrivance, made 
 to fall upon the excretion, which is thereby perfectly deo- 
 dorized. The receptacle containing this dry excrement is 
 emptied from time to time without any smell or danger, and 
 after storage for as long as may be necessary in a sheltered 
 place, the mixture forms a valuable and inodorous manure, 
 worth from 21. to 31. per ton. [See Moule's Pamphlet, p. 12.] 
 If it should be desirable, this manure, when dry and pul- 
 verized, may be again used three or four times over, instead 
 of common dry earth, the value of the manure being neces- 
 sarily increased after each using. The amount of this increase 
 has not, as far as we know, been calculated, so it yet remains 
 to be seen whether using the dry fsecal matter over again, or 
 introducing new earth into the closet-cistern, is more profit- 
 able in the value of the total amount of manure produced. 
 Mi. Moule's earth-closets have been introduced with success 
 
14 EEirEDIES. 
 
 at Wimbledon Camp [see Appendix to Twelfth Annual Re- 
 port of the Medical Officer to P. Council by Dr. Buchanan^ ; 
 and has met with such success in India as to obtain for its 
 inventor a donation of 500Z. from tbe Secretary of State for 
 India, together with the most flattering eulogiums. [Pamphlet> 
 pp. 1 and 23.] 
 
 The advantages of the system have been so ably sum- 
 marized by Dr. Buchanan, that we give his words in extenso: — 
 
 " 1. The earth-closet, intelligently managed, furnishes a 
 means of disposing of excrement without nuisance, and 
 apparently without detriment to health. 
 
 "2. In communities, the earth-closet system requires to 
 be managed by the authority of the place, and will pay, at 
 least, the expenses of its management. 
 
 " 3. In the poorer class of houses, where supervision of 
 any closet arrangements is indispensable, the adoption of the 
 earth system offers especial advantages. 
 
 " 4. The earth system of excrement removal does not 
 supersede the necessity for an independent means of re- 
 moving slops, rain-water, and soil-water. 
 
 " 5. The limits of application of the earth system in the 
 future cannot be stated. In existing towns, favourably ar- 
 ranged for access to the closets, the system might at once be 
 applied to populations of 10,000 persons. 
 
 " 6. As compared with the water-closet the earth-closet 
 has these advantages : — It is cheaper in original cost ; it 
 requires less repair ; it is not injured by frost ; it is not 
 damaged by improper substances being thrown down it ; and 
 it very greatly reduces the quantity of water required by 
 each household. 
 
 " 7. As regards the application of excrement to the land, 
 the advantages of the earth system are these : the whole 
 agricultural value of the excrement is retained ; the re- 
 sulting manure is in a state in which it can be kept, carried 
 
EEMEDIES. 15 
 
 about and applied to crops with facility ; there is no need for 
 restricting its use to any particular area, nor for using it at 
 times when, agriculturally, it is worthless ; and it can be 
 applied with advantage to a very great variety, if not to all, 
 crops and soils. After the disposal of excrement by earth, 
 irrigation will continue to have its value as a means of ex- 
 tracting from the refuse water of a place whatever agricul- 
 tural value it may possess, for the benefit of such crops and 
 such places as can advantageously be subjected to the process." 
 
 There can be little doubt, however, that 10,000 is too large 
 a limit, for in order to ensure the proper and advantageous 
 working of the system, it appears to be necessary that all 
 the closets should be under the supervision of one authority, 
 which would be difficult to bring about in practice in a town 
 of 10,000 inhabitants. It will be observed also that the 
 valuable liquid filth is not in any way treated by Moule's 
 system, so that in order to prevent river pollution in any 
 district where the earth-closets have been set up, a system of 
 irrigation, filtration, or some other approved mode of dealing 
 with the liquid sewage would have to be adopted in addition. 
 Taking for granted that irrigation is the most successful of 
 them, it will be a question whether the liquid sewage, minus 
 all the valuable constituents abstracted by Moule's process, 
 could be utilized in such a manner as to pay its expenses. 
 
 We fear, however, that the difficulty of dealing with the 
 liquid sewage (apart from the solid excrement) would be too 
 great to permit of the adoption of earth-closets, in large or 
 even moderate-sized towns. 
 
 At the same time, while considering Mr. Moule's system, 
 it may be remarked that in the highly successful mode of 
 treatment of the sewage by irrigation pursued at Bedding- 
 ton (Croydon), the solid matter is separated from the liquid 
 before distribution over the land. 
 
 How far the liquid sewage may be enriched by the pre- 
 
16 BEMEDIES. 
 
 sence, even for a very short time, of tte solid faecal matter, 
 I know not how to estimate, but I should imagine that the 
 solid refuse was more likely to gain in fertilizing power than 
 the liquid ; which is borne out by the fact that although Mr. 
 Moule, in his own pamphlet, only claims a value of from 2Z. 
 to 31. per ton for the solid manure refuse from his closet, we 
 learn through Mr. Latham that the manure manufactured 
 from the solid matter .retained in the filters at Beddington is 
 worth about 31. 10s. per ton. Theoretically, then, there 
 Vfould seem to be no reason why the " dry earth " and the 
 " irrigation " system should not be adopted together in any 
 moderate-sized town or district ; but how far, in practice, 
 such a combination would be superior to the water-closet and 
 irrigation system, as has been adopted at Beddington and 
 elsewhere with so much success, has yet to be determined. 
 We confess that we are not very sanguine as to the result, 
 although we have no doubt that in villages and large public 
 buildings, especially in the country, where the liquid sewage, 
 house slops, &c., can be easily and profitably disposed of and 
 utilized on the neighbouring gardens and fields, we think the 
 earth-closet may be adopted with very great advantage. 
 
 An attempt has been lately made [1 jB. P. C, p. 50] by 
 Mr. W. J. Garnett, of Quernmore Park, near Lancaster, to 
 get the house scavenging of the town done upon a modifica- 
 tion of the dry-earth system, and to deal with the whole 
 excrement of the household instead of only the solid refuse. 
 By daily collection in tubs and pans the whole excrement 
 is collected from a large number of houses, and the pay- 
 ment of a penny per week per house is said to secure the 
 collection of the chamber slops as well as of the privy con- 
 tents. Nearly one-tenth of the town is thus dealt with. 
 Earth is sent round daily and thrown into the privy holes, 
 and when the pit is full the whole is taken to a depot, where 
 it is mixed with material derived partly from street sweep- 
 
REMEDIES. 17 
 
 ings and ash-pit refuse ; and being thereafter piled beneath 
 a shed built upon a farm near the town, the whole is soaked 
 with the collected urine. A sample analyzed proyed to 
 contain — 
 
 Organic matter and ammonia containing • 207 of tot. comb. nit. 6 • 671 
 Mineral matter containing • 326 of phosphoric acid .. .. 66 '782 
 Water 26-547 
 
 These figures indicate a practical value much smaller than 
 would have been supposed, and it is evident from the small 
 amount of total combined nitrogen, that much of the urine 
 escapes preservation. The results are certainly curious. 
 [1 B. P. G., p. 50.] 
 
 III. 
 
 The second class of remedies of which we have to speak, 
 are those which deal with the sewage after it has been passed 
 into the drains and mingled with the entire liquid refuse of 
 the houses and streets of the district, and most generally, 
 under our present system of town drainage, with the surface 
 water and unintereepted rain water of the place. There are 
 three principal ways, under this head, in which it has been 
 attempted to deal with town sewage : — 1. Precipitation by 
 chemical means; 2. Filtration; 3. Irrigation. Of these the 
 second is, in practice, only an artificial and imperfect modi- 
 fication of the last ; but we are not prepared to say that 
 under peculiar circumstances and in certain localities an 
 artificial system of filtration may not be adopted with advan- 
 tage, and we will say a few words upon the subject in connec- 
 tion with what has been called plant-filtration, or irrigation. 
 Precipitation by chemical means is certainly the most 
 attractive form of sewage utilization, and although nothing 
 has as yet been achieved at once practical and remunerative, it 
 
 
 
18 
 
 REMEDIES. 
 
 seems impossible, considering the rapid advance of scientific 
 knowledge, that we can long remain without some chemical 
 composition, which will fulfil all requirements. The pre- 
 ser-yation of the ammonia can alone render any process of 
 precipitation remunerative, but that subtle chemical enigma 
 has so far eluded the vigilance of the chemists ; and never 
 fails to fiy oif during treatment, either entirely or in such 
 large proportions as to leave nothing but a worthless manure 
 behind it. 
 
 We will now notice the principal experiments in this 
 direction, with their success or results. 
 
 1. The sewage has been treated with lime at Tottenham, 
 at Blackburn, and at Leicester. The modus operandi is simple, 
 but the treatment entirely fails to get rid of the organic nitro- 
 genous matter in the sewage, and consequently to render the 
 liquid sewage admissible into a river. We subjoin a table of 
 the analyzed results of the lime process, which may be inter- 
 esting in many ways. 
 
 Peeoipitate of Sewage by Ldie. 
 
 
 Before 
 Treatment. 
 
 After 
 Treatment. 
 
 Precipitate. 
 
 Organic matter : — 
 
 (a) Insoluble suspended . . 
 (6) Soluble 
 
 Lime 
 
 Magnesia 
 
 Soilii 
 
 Potash 
 
 Common salt . . 
 
 Sulphuric acid . . 
 
 Phosphoric acid 
 
 Carbonic acid . . 
 Silica, sand, oxide of iron, &c. 
 
 39-10 
 
 19-40 
 
 10-13 
 
 1-42 
 
 4-01 
 
 3-66 
 
 26-40 
 
 5-34 
 
 2-63 
 
 9-01 
 
 6-20 
 
 19'-'35 
 9-28 
 0-94 
 2-26) 
 3-80 
 
 24-49 ) 
 5-99 
 0-45 
 5-19 
 0-23 
 
 35-41 
 
 14-80 
 
 0-22 
 
 1-02 
 
 1-11 
 2-06 
 8-92 
 5 ■ HO 
 
 
 127-30 
 
 71-98 
 
 69-50 
 
 Ammonia 
 
 7-48 
 In solution only. 
 
 7-50 
 in solution only. 
 
 2-80 
 
EEMEDIES. 19 
 
 1st. It may be remarked that no organic matter is precipi- 
 tated except that which would have been equally separated by 
 mechanical filtration. 
 
 2nd. The ammonia in the precipitate is entirely due to the 
 same insoluble organic matter, and none of the ammonia of 
 the liquid is saved by this process. 
 
 3rd. Five-sixths of the phosphoric acid are precipitated. 
 But as this is the only element of agricultural value preserved 
 by the lime process, it may be safely affirmed that it can never 
 be profitable in an agricultural sense. [See 2 S. U. 0., p. 69, 
 and Tott. Bep., p. 10.] 
 
 2. Lime and chloride of iron have been tried without satis- 
 factory results at Northampton. The chloride of iron delayed, 
 without preventing, the putrescence of the effluent fsscal 
 matter; and the Court of Chancery at length stepped in 
 and restrained the Improvement Commissioners from dis- 
 charging any more sewage into the river after June 1, 1870. 
 [1 B. P. C, 58.] 
 
 3. At Stroud, in Gloucestershire, sulphate of ammonia has 
 been tried with partial success, but under circumstances 
 which would not warrant its adoption elsewhere ; the sewage 
 being very weak and the effluent liquid containing more solid 
 matter in suspension than the sewage before treatment. 
 [1 B. P. G., 59.] 
 
 4. A somewhat more complicated mode of treatment, known 
 as Solden's process, seems to combine all the disadvantages 
 of the foregoing system. The sewage is treated with a mix- 
 ture of sulphate of iron, lime, and coal-dust, and has been 
 tried, among other places, at Bradford. According to the 
 analysis on page 60 of the E. P. C, we find that not only is 
 the amount of the putrescible organic matter in solution in 
 the sewage absolutely increased by treatment, but that the 
 amount of solid matter in solution is also increased, and the 
 effluent water rendered in addition so permanently hard as 
 
 c 2 
 
20 EEIIEDIES. 
 
 to be very objectionable for manufacturing purposes. In 
 addition to this the solid refuse obtained may be considered 
 practically worthless as a manure. [1 B. P. G., 60.] 
 
 5. Experiments have been also tried vi^ith sulphate of 
 alumina, with results not greatly different from those of the 
 lime process [see ante, table, p. 18] ; the precipitate on the 
 whole, however, being of less value as a manure [2 S. U. C, 
 70-71] ; but see post as to the Phosphate of Alumina, pp. 
 22-25. 
 
 6. In Blyth's process, the polluting matter in the sewage 
 is precipitated by soluble phosphate of magnesia, but the 
 results of experiments are not satisfactory. [2 S. U. C, 71-72.] 
 
 7. In Lenk's process, the sewage was treated with a pre- 
 paration of alum, the deposit being valued as a manure by 
 Professor Voelcker at about 2Z. 2«. per ton dry, and 25s. to 
 30s. in a semi-dry state. The deodorizing fluid was tried at 
 Tottenham with very fair results [Totten. Sep., pp. 30-35], 
 and Dr. Voelcker reports favourably upon the disinfecting 
 power of Lenk's composition \_icl., p. 34]. 
 
 The reader is also referred to an interesting American 
 pamphlet upon this process, in which a fully detailed account 
 mil be found of the mode of treatment and results. 
 
 8. The best practical precipitants of sewage, according to 
 Messrs. Hofmann and Frankland [Be]}, add. to Met. Bd. 
 of Works, 12th August, 1859, whose opinion is endorsed by 
 the Eoyal Commissioners in this Second Eeport of 1861], 
 are the persalts of iron. Of these, the perchloride of iron 
 may be considered as the most valuable, and its high price 
 alone appears to interfere with its adoption. But it has been 
 suggested that in case of a large demand it might be pro- 
 duced " at a price suf&ciently moderate to allow of its general 
 employment in the purification of sewage " [2 S. U. C, 1861, 
 page 18, and id., Appendix 6.] We cannot do better than 
 quote the words of this Eeport as to the advantage of sewage 
 
EEMEDIES. 21 
 
 treatment with perchloride of iron. When perchloride of 
 iron is added to sewage, a precipitate is formed which rapidly 
 settles down, leaving above it a clear liquid. This precipi- 
 tate is chiefly composed of peroxide of iron, precipitated not 
 by the acids of the sewage as in the case of the alkaline 
 precipitants, but by the alkalinites of the carbonate of 
 ammonia and other compounds of the same nature which 
 exist in, or are rapidly formed from, the urine and feeces 
 of the liquid. The deposit so formed contains, of course, 
 all the suspended matter of the sewage, whether organic or 
 otherwise ; it also contains, and to a greater extent than in 
 the case of the lime process, the phosphoric acid previously 
 existing in the sewage in a soluble form ; moreover, and this 
 constitutes about all the advantage of this method of pre- 
 cipitation, in the precipitate is removed the sulphuretted 
 hydrogen, which in the case of the lime process remains as 
 a sulphuret in the liquid. The value of a precipitating 
 process depends upon the extent to which it fulfils the very 
 different, but equally necessary, requirements of a mechanical 
 clearing of the liquid and of its chemical purification. Salts 
 of peroxide of iron (or more properly persalts of iron) when 
 neutralized by an alkali give a large flocculent precipitate 
 of peroxide of iron, which is extremely well adapted for 
 the mechanical separation of the suspended particles. The 
 resulting precipitate rapidly settles down, and the clear 
 liquid is easily separated from it. In this respect, the iron 
 compounds hold a high rank as a means for the purification 
 of sewage. But moreover, in this precipitate is removed, 
 as we have before seen, the sulphuretted hydrogen in the form 
 of sulphuret of iron, a compound quite innocuous and not 
 readily decomposed by subsequent agencies. Oxide of iron 
 has also the property, like alumina, of carrying down with it 
 organic matter in solution, and we have reason to believe 
 that it does practically remove animal matter, which would 
 
22 REMEDIES. 
 
 otherwise be left in the discharged liquid. The result of 
 these conjoined actions is, that with the iron process we are 
 able to separate town sewage with great facility into solid 
 and liquid, both of which are comparatively free from 
 noxious or offensive smell, and neither of which is liable to a 
 recurrence of this evil quality. [2 S. U. C, pp. 16-17]. As 
 regards the best mode of obtaining perchloride of iron, see 
 Appendix, p. 73. 
 
 9. We have now to notice a chemical process which seems 
 likely to take the place of all those that have hitherto been 
 invented, and to play a very prominent part in sewage utiliz- 
 ation, namely, the Phospliate process. The most interesting 
 experiments upon this system have been made at Tottenham, 
 when the Lime process adopted some time ago may be said to 
 have almost completely failed ; and we refer our readers for an 
 admirable expose of the new system to a Eeport published on 
 the subject by Mr. P. P. Marshall, C.E., the engineer to the 
 Tottenham Local Board of Health. 
 
 The sewage is treated in this process with phosphate of 
 alumina, a natural product existing in large quantities on the 
 island of Altovola, near St. Domingo, in the West Indies, and 
 proem-able at about 31. 10s. per ton. The essential difference 
 between this and any other system of deodorizing sewage is 
 that the agent employed contains the most valuable fertiliz- 
 ing properties itseK, and these properties can only be made 
 available by a process of precipitation. All other methods 
 are simply precipitant, and the consequence has been that 
 the maniire made from the sewage has been little better than 
 mud. [See Analyses of Composition, pp. 18 and 28.] 
 
 The phosphate process has a twofold character, and com- 
 bines the principles of irrigation and chemical precipitation, 
 or it can be used independently of irrigation, if that course 
 be preferred. In one case, if the phosphate of alumina alone 
 is used, the sewage is defecated, the solid matter in the 
 
REMEDIES. 23 
 
 sewage is precipitated, and the water is left ; the latter, it is 
 stated, " still maintaining all its nitrogenous and valuable 
 properties, jplus any excess of phosphoric acid which has been 
 added, and therefore highly useful for the irrigation of cereals 
 and other crops, and at the same time perfectly inoffensive." 
 This application of the process would be suitable where it 
 was deemed desirable to use the water as a fertilizing agent 
 for irrigation purposes. In the case of towns where sewage 
 irrigation presents peculiar difficulties, and where it is desired 
 to render the sewage sufficiently clear and pure to mingle 
 with a river or stream, this object, it is stated, " can be 
 obtained by adding a small quantity of lime to the sewage, 
 after the treatment by the former process, by which means 
 the excess of phosphate and organic matter is precipitated, 
 and the water so clarified is rendered tasteless and harmless." 
 In either case it is claimed that the sewage is effectually 
 defecated, and rendered free from all trace of putridity. Of 
 coiu-se the precipitate or deposit has to be removed from the 
 precipitating tank and dried, in order to be converted into a 
 portable manure. This is accomplished by means of an 
 Archimedian screw, and the precipitate is dried and pulver- 
 ized in a large open shed. 
 
 Process. — The phosphate of alumina is rendered soluble in 
 water by the application of sulphuric acid in proportions of 
 about 2 to 1, and is then mixed with water until the whole is 
 reduced to the consistency of thick chocolate for driuking- 
 [Marshall, Mep., p. 7.] This composition is then applied to 
 the sewage, and afterwards run into a- series of tanks. After 
 precipitation " the water is finally passed through a filter 
 composed of coke, charcoal, or some other carbonized sub- 
 stance, so as to remove any organic matter that may remain 
 in solution. This filter is re-oxidized by exposure to the 
 atmosphere, the water being run out and the air admitted 
 every twelve hours alternately." The deposit is afterwards 
 
24 EEMEDIES. 
 
 removed into shallow pans to dry, and when of sufficient 
 consistency is made into bricks and air dried. The whole 
 process is remarkably free from smell, in consequence of the 
 phosphate in the precipitating composition. 
 
 The practical results of the process are most satisfactory, 
 and for a detailed account of them we must refer our reader 
 to Mr. Marshall's exceedingly impartial Eeport [pp. 9-18] , 
 and to Dr. Voelcker's letter or Eeport on the whole process 
 (6th April, 1871), and printed in the Appendix to Mr. 
 Marshall's work. [See also Evening Standard, December 26, 
 1871.] 
 
 Professor Voelcker's analyses show that the raw sewage at 
 the time of his visit contained 16J grains of suspended matter 
 per gallon, while the effluent water yielded " no perceptible 
 and weighable suspended matters." The gallon of raw 
 sewage held 57 grains of solid matter in solution, while the 
 eflBuent had 63 grains, there being a large increase of sulphate 
 of lime. Of organic matter the gallon of raw sewage held 
 in solution 6 ■ 35 grains, and the effluent 5 • 74. In suspension 
 the raw sewage held 11-41 grains, and the effluent none. 
 Of mineral matter the gallon of raw sewage held in solution 
 50 ■ 80 grains, and the effluent 57 • 71. In suspension the raw 
 sewage held 5-11 grains, and the effluent none. Thus the 
 total solid matter, organic and mineral, was 73 • 67 grains per 
 gallon in the raw sewage, and 63-45 grains in the effluent. 
 The total organic nitrogen in the gallon of raw sewage was 
 1-60 grain, of which 0-96 were in solution. The effluent 
 had simply 0-47 in solution. This would be equal to 
 1-94 grain of ammonia in the raw sewage, and 0-57 in 
 the effluent. The saline ammonia in the raw sewage was 
 2-66 grains, and in the effluent 3-32. Finally, the total 
 nitrogen, calculated as ammonia, was 4-60 grains per gallon 
 in the raw sewage, and 3-89 in the effluent. " It foUows 
 from these results," says Professor Voeloker, " that sewage 
 
REMEDIES. 25 
 
 by treatment with the phosphate of alumina process is 
 deprived of by far its largest proportion of nitrogenous 
 organic matter." 
 
 Theoretically, and indeed as far as the experiments have 
 so far shown, the process is highly remunerative, the value 
 of the manure having been estimated by Professor Voelcker 
 at from 21. 10s. to 71. Is. per ton. Mr. Marshall estimates 
 the cost of producing three tons of manure at Tottenham 
 at about 9Z. [Report, p. 16.] The manure which has been 
 produced at Tottenham by some experiments conducted under 
 decidedly unfavourable circumstances sells for dZ. per ton, 
 thus giving a profit of 11. per ton on the estimated working 
 expenses. The extreme simplicity of the phosphate process 
 is one of its greatest recommendations ; we cannot believe in 
 the practical success of any system that cannot be worked in 
 a rough way. As far as deodorization is concerned, the 
 phosphate leaves nothing to be desired, and speaking from 
 personal observation we can say that not only the effluent 
 water, but the deposited mud, is perfectly free from any 
 offensive odour. 
 
 10. We have now to notice somewhat more fully a process 
 which has attracted a large and we cannot but think an 
 undue share of public attention, and which is known by the 
 name of the A B G system, or Siller's patent. The following 
 is the specification filed at the Great Seal Patent Office : — 
 
 " We add to the sewage to be purified a mixture consisting 
 of the following ingredients : — Alum, blood, clay, magnesia, 
 or one of its oompoimds, by preference the carbonate or the 
 sulphate, manganate of potash, or other compound of manga- 
 nese, burnt clay otherwise known as ballast, chloride of 
 sodium, animal charcoal, vegetable charcoal, and magnesian 
 limestone. Of these substances the manganese compound, 
 the burnt clay, chloride of sodium, and magnesian limestone 
 may be omitted, and it is not essential that both animal and 
 
26 REMEDIES. 
 
 vegetable charcoal should be used. If any of the ingredients 
 named should from any cause be present in sufficient quantity 
 in the sewage it may of course be omitted from the mixture. 
 The proportions in which the ingredients are to be used vary 
 according to the nature of the sewage to be purified, as, for 
 instance, if a large proportion of lu-ine is present we increase 
 the proportion of clay ; if the sewage is much diluted, we 
 slightly increase the proportion of alum and blood ; if it 
 contains a large proportion of street refuse we decrease the 
 proportion of clay. 
 
 " For ordinary sewage the following proportions have 
 answered well : — 
 
 Alum 600 parta. 
 
 Blood .. 1 „ 
 
 Clay 1900 „ 
 
 Magnesia 5 » 
 
 Manganate of potash 10 „ 
 
 Burnt clay 25 „ 
 
 Chloride of sodium . . 10 „ 
 
 Animal charcoal 15 i, 
 
 Vegetable charcoal 20 , 
 
 Magnesian limestone 2 „ 
 
 "These substances are mixed together and added to the 
 sewage to be purified until a further addition produces no 
 further precipitate. The quantity required will be about 
 4 lbs. of the mixture to 1000 gallons of sewage. In many 
 cases it is preferable to mix the above compound with a small 
 quantity of water, and add it in a liquid state to the sewage. 
 The sewage must then be thoroughly mixed with the com- 
 pound and allowed to flow into settling tanks. The greater 
 part of the organic and other impurities will be immediately 
 separated in the form of large flakes, which rapidly fall to 
 the bottom, leaving the supernatant water clear and inodorous, 
 or nearly so. The water may then be allowed to flow away 
 
REMEDIES. 27 
 
 into a river, or be disposed of in any other way, and the 
 sediment or mud allowed to accumulate at the bottom of 
 the tank. In some cases it is preferable to add the compound 
 of manganese to the water after the sediment produced by the 
 other ingredients has been allowed to subside. The sediment 
 will be found to possess the power of precipitating a further 
 quantity of sewage ; it must therefore be pumped or other- 
 wise taken from the tank and mixed with fresh sewage, the 
 sediment being allowed to subside in the same way as before. 
 The sediment may be used five or six times over in this way. 
 When the sediment no longer possesses the power of precipi- 
 tating the impurities in the sewage, it must be removed from 
 the tank and allowed to dry ; when partially dry a small 
 quantity of acid, by preference sulphuric acid, may be mixed 
 with it, which will retain all the ammonia in a soluble form. 
 When dried the sediment will be a valuable manure." 
 
 A series of experiments were conducted, chiefly at Leicester 
 and at Leamington, upon the ABC system, and the results 
 published in the early part of the year 1870 as the 2nd Eeport 
 of the E. P. C. They were, on the whole, unsatisfactory ; 
 and the patent mixture appears to be in no way superior to 
 lime in its effect upon the sewage. The amount of organic 
 nitrogen indeed, including the most putrescent particles of 
 the sewage, the most injurious to health and the most 
 valuable as a manure, seems to be nearly as great in the 
 effluent water as in the raw sewage. Again, in consequence 
 of the ammonia contained in the alum used in the ABC pro- 
 cess, the effluent water invariably contains more ammonia 
 than the raw sewage, a result equally fatal to the purity of 
 the water and the value of the residuum as a manure. 
 
 The smell arising from the process is pronounced offensive 
 to an extent which would make it a " nuisance " whenever 
 conducted in or near a town. [2 B. P. C, p. 8.] 
 
 The results of some experiments upon the London sewage 
 
28 REMEDIES. 
 
 by the ABC process, wliicli are considered to have been 
 very accurately conducted, are summed up in p. 13 of this 
 Eeport in the following words [2 B. P. C, p. 13] : — 
 
 " We learn then from the above results : — 
 
 " 1st. That of the dissolved matters those left on evapora- 
 tion were increased in weight by nearly one-half the amount 
 of soluble ingredients added to the sewage ; for the 'ABC 
 mixture making up 100,000 parts with the sewage to which 
 it was added contained, according to our analysis, 27 '8 
 parts of soluble matters left on evaporation, whilst the 
 increase of soluble matters left on evaporation, shown in the 
 above table, amounts to 13 '2 parts. 
 
 " 2nd. That the organic carbon in the dissolved matters 
 was diminished to the extent of 37 ' 5 per cent. 
 
 " 3rd. That the organic nitrogen in the dissolved matters 
 underwent no alteration; consequently, the organic matters 
 precipitated from solution by the 'ABC mixture were 
 non-nitrogenous, and therefore valueless as manure. 
 
 ■' 4th. That the proportion of ammonia was augmented, 
 because more was added in the 'ABC mixture than was 
 precipitated by the action of that mixture upon the sewage. 
 100,000 parts of the 'ABC mixture gave on analysis 
 132' 1 parts of ammonia; there was consequently added to 
 each 100,000 parts of sewage in the 'ABC' mixture, 
 1 ■ 32 part of ammonia, whilst the augmentation of ammonia 
 shown in the above table is • 668 part. 
 
 " 5th. That no nitrates were formed in the operation. 
 
 " 6th. That the total combined nitrogen was augmented by 
 the ammonia added in the 'A B C ' mixture; consequently, 
 as regards soluble constituents, the efSuent liquid possessed 
 a greater manure value than the raw sewage, the increase 
 in value being due to the ammonia in the chemicals em- 
 ployed. 
 
 " 7th. That the proportion of chlorine remained unaltered. 
 
REMEDIES. 29 
 
 " 8th. That the matters in suspension, both mineral and 
 organic, were almost completely removed, although the de- 
 fecated sewage remained perceptibly turbid." 
 
 With regard to the manure value of the solid refuse, after 
 treatment by the "ABC" process, it seems clear that 
 unless the mud is greatly strengthened by the addition of 
 other substances valuable as manures, its practical value is 
 exceedingly small. For, although in theory, a certain num- 
 ber of tons of valuable constituents are separated daily from 
 the raw sewage, yet they are mixed with so large an amount 
 of clay and other substances of no value, as to render the 
 refuse on the whole hardly worth the carriage. Such being 
 the state of the case, we can enter into no further details 
 upon this branch of the subject, but merely refer such as 
 may desire further information as to the md;nure resulting 
 from the "ABC" system of treatment to 2 E. P. C. (1868), 
 1870, pp. 15-18. 
 
 As to the "ABC" system generally, we find the follow- 
 ing CoNCLTJSiONS at p. 19 of the 2 E. P. C. : — 
 
 " 1. The process removes a large proportion of the ms- 
 pended impurities from sewage, but on no occasion, when we 
 have seen it in operation, has this removal been so complete 
 as to render the efiluent sewage admissible into running 
 water. 
 
 " 2. The 'ABC process removes a very small propor- 
 tion of the soluble polluting matters from sewage. After 
 treatment by this process, the effluent sewage is very little 
 better than that which is obtained by allowing raw sewage 
 to settle in subsidence tanks." 
 
 "3. The manure obtained by this process has a very 
 low market value; and cannot repay the cost of manu- 
 facture. 
 
 " 4. The manipulations required for the extraction and 
 drying of this manure are attended with a nauseous odour, 
 
30 EE5IEDIES. 
 
 especially in warm weather, and would occasion a serious 
 nuisance if tlie works were situated in or near a town." 
 
 Finally, as regards the purification of sewage by charcoal, 
 see further, generally, 2 S. U. C. (1861), pp. 14-21. 
 
 11. Among the systems of treating sewage by chemical 
 means, we must not omit that recently invented by Major- 
 General Scott, E.E., and which has been tried under his 
 superintendence at Ealing. 
 
 In this process the sewage is treated with lime and clay, 
 made into a thick paste and mingled with the sewage, as it 
 flows into a tank about 60 feet in length. The precipita- 
 tion is so rapid that the effluent water is almost tasteless, and 
 the process is said to be entirely unattended with any offen- 
 sive odour. But the peculiar feature of the system is the 
 subsequent treatment of the refuse, which is dried and burnt 
 with the help of its own organic matter, and when pulverized 
 has all the properties of the best Portland cement. 
 
 This ingenious process has been in operation but a short 
 time, but has so far been perfectly successful. See Appen- 
 dix v., p. 55, as to Hille's process. 
 
 Filtration. — The process of filtration through sand, gravel, 
 chalk, or certain kinds of soil, if properly carried out, is the 
 most effective means for the purification of sewage to which 
 reference has yet been made ; indeed, irrigation, as now 
 carried out, owes no inconsiderable amount of its success to 
 the contemporaneous effect of the filtration of the sewage 
 through the soil of the irrigated fields; for it is precisely 
 in those cases in which the sewage is absorbed and disappears 
 in porous land, that we have observed, in the effluent water 
 from drains, the most complete purifying effect. 
 
 The water pumped from the shallow Wells in London is 
 nothing but filtered sewage, a large volume of which, be it 
 remarked in passing, exists in the ornamental water in St. 
 James's Park, which is supplied from the well on Duck Island. 
 
EEMEDIES. 31 
 
 Irrigation is of course the most natural way of getting 
 sewage filtered, and while its adoption has generally met 
 with success, all the more artificial systems of filtration which 
 have been hitherto tried have proved complete failures. 
 
 At Ealing, for instance, the liquid sewage is received in 
 tanks, and forced upward through filters of burnt clay, bal- 
 last, gravel, and charcoal. The process, which will be found 
 fully entered into in 1 E. P. C, pp. 60-70, entirely failed to 
 transform the soluble putrescent organic matter into innocu- 
 ous mineral compounds. This failure, we quote the Eeport, 
 is due partly to the filters being too small for the volume of 
 sewage dealt with, and partly to the circumstance that the 
 filtration is performed upwards instead of downwards. For 
 efficient purification by filtration, it is essential that the 
 atmospheric oxygen should have frequent access to the in- 
 terior of the filter, a condition which is entirely excluded in 
 upward filtration. A very interesting course of experiments 
 upon filtration will be found recorded in 1 K. P. C, pp. 60-70, 
 and Tottenham Eep., pp. 49-69. Average London sewage 
 was filtered through sand, sand and chalk, Beddington soil, 
 Hambrook soil. Barking soil, Dursley soil, and Ley land peat, 
 with various results. There is no doubt that the sewage 
 may be effectually purified by filtration through almost any 
 porous soil, when applied in quantities not greater than 5^ 
 gallons per cubic yard of soil per diem, in almost aU soils up 
 to nearly 10 gallons per cubic yard in the case of Dursley 
 soil, the most efficacious in this respect of any which were 
 submitted to experiment. In the case of peat, an application 
 of about 4 gallons per cubic yard was successful. 
 
 It is computed that the sewage of a water-closet town of 
 10,000 inhabitants could be cleansed upon five acres of land 
 drained to the depth of six feet [1 B. P. C, 65]. Upon this 
 purifying power of the soil is based Mr. Bailey Denton's 
 ingenious scheme of intermittent downward filtration, a 
 
32 EEMEDIES. 
 
 scteme for whose details we must refer our readers to his 
 recent publication, 'The Sewage Question,' 8vo, 1871. "We 
 do not, however, believe in the advantage of this artificial 
 system for many reasons, amongst others — 
 
 1. It is entirely unremunerative, the amount of sewage 
 applied to a given area of land being probably in such a 
 case too great to admit of the growth of any ordinary agri- 
 cultural crop. 
 
 2. The whole of the manure ingredients of the sewage 
 would be absolutely wasted. 
 
 3. The collection of solid fsecal matters upon the surface 
 of the soil, with no vegetation to make use of them, would 
 probably give rise to a formidable nuisance, especially in 
 hot weather. . . . The action of the filter must not be 
 considered as merely chemical. The process carried on 
 in it is also mechanical. Filtration, properly carried out, 
 results in the oxidation and transformation of offensive 
 organic substances in solution, as well as in the mere 
 mechanical separation of the suspended solid matters, 
 which, when in motion, sewage conveys with it. [ Tott. Hep., 
 pp. 67-68.] 
 
 With reference to this scheme of Mr. Bailey Denton, Pro- 
 fessor Voelcker says : — " The greater portion of the soluble 
 alkaline medicinal salts, together with the products of oxidi- 
 zation of the nitrogenous constituents of faeces and urine, 
 cannot be removed by filtration through any amount of soU. 
 The efHuent water is not fit for use until mixed with other 
 pure water." 
 
IRRIGATION. 33 
 
 IV.— lEEIGATION. 
 
 The last mettod of dealing with sewage wHcli will engage 
 our attention is Irrigation, or continuous application of the 
 sewage to cultiyated land, which is laid down by the S. U. 
 Commission in their third Eeport, 1865, p. 3, to be "the 
 right way to dispose of town sewage, and the only one by 
 which the pollution of rivers can be avoided." Although 
 this is, perhaps, going rather too far, there can be little 
 doubt that, regarded from every point of view. Irrigation is 
 on the whole the most practicable mode of disposing of town 
 sewage that has yet been tried. To obtain a maximum 
 amount and gross value of produce from a given amount of 
 sewage, it should be applied in small quantities per acre and 
 in dry weather ; but the great dilution of town sewage, its 
 large daily supply at all seasons, and its greater amount in 
 wet weather, when the land can least bear or least requires 
 more water, render it quite inappropriate for application on 
 a comprehensive scale to arable land for corn and other 
 ordinary rotation crops. As to the mistakes that have been 
 committed in adopting systems of sewage irrigation, espe- 
 cially as to the area of the land under irrigation, the use of 
 hose and jet, and the kind of crops to be manured, see 
 1 S. U. C, pp. 17-20. 
 
 Having regard to the cost of distribution, it is probable 
 that the most profitable mode of utilization would be to 
 limit the area by specially adapting the arrangements for 
 the application of the greater part, if not the whole, to 
 permanent or other grasses laid down to take it the year 
 round ; trusting to its occasional use to other crops within 
 easy reach of the line or area so commanded, but relying 
 mainly on the periodically broken-up rye-grass land, and on 
 the application to arable land of the solid manure resulting 
 
 D 
 
34 IRRIGATION. 
 
 from the consumption of the sewaged grass, for obtaining 
 other produce than milk and meat, by means of sewage. 
 
 Judging both from the results of the experiments and 
 from the experience of common practice, it is considered that 
 the most profitable utilization of town sewage will in most 
 cases be attained by the application of about 5000 tons per 
 acre to meadow or Italian rye-grass, but that the farmer would 
 not pay f d., and probably not id. per ton the year round for 
 sewage of the average strength of that of the metropolis 
 (excluding storm-water) delivered on his land. [3 S. U. C, 
 pp. 78-80.] 
 
 It is also necessary, in order to bring about the most pro- 
 fitable results, that the liquid sewage should only be applied 
 to such crops as are known to be specially benefited by it. 
 There seems to be no doubt that meadow land is the most 
 fitted for the reception of sewage ; and of all grasses, perhaps 
 the Italian rye-grass is the cto]) that derives most benefit 
 from its application. There is no doubt that many other 
 crops, such as turnips or mangold-wurzel, would be immensely 
 improved by occasional sewage dressing ; but it must always 
 be borne in mind that in order to make sewage irrigation 
 successful, it must be constantly applied to the same area of 
 ground. "We have already shown that it is most undesirable 
 to extend the operation over too large an extent of land, and 
 it is evident that if the sewage is to be applied to a small area, 
 it must be continually flowing on to the land. Now in no 
 crop can this be permitted but on grass land. A system of 
 intermittent application to various fields on a farm by means 
 of hose and jet has been tried, but the expense as well as the 
 difiiculty of applying the sewage only when it was required 
 by the crop led to its failure. Upon this branch of the subject, 
 see 1 S. U. C, 17 ; and as regards the distribution of sewage 
 in the neighbourhood of large towns, Tottenham Mep., p. 91, 
 where it is stated that the visit to Barking satisfied " the 
 
lEElGATION. 35 
 
 Committee that sewage farming near London ought to be 
 market gardening." 
 
 It will be well to bear in mind, while considering the 
 various modes of sewage irrigation, that the chief valuable 
 ingredients in ordinary sewage are : 1st, the various forms 
 of nitrogen ; 2nd, phosphoric acid. The money value of 
 these constituents in solution in 100 tons of average sewage 
 is about 15s. ; while the matter in suspension in the same 
 quantity is worth only about 2s. [Tottenham Bep., p. 9]. The 
 latter only is retained by precipitation, the former can only be 
 separated by chemical agency on the action of plants grow- 
 ing in the soil through which the sewage is filtered. The 
 advantage of plant-filtration, which retains the matter in solu- 
 tion, over merely mechanical filtration, which only retains 
 that in suspension, becomes immediately clear. 
 
 Before proceeding any farther to consider the merits of 
 sewage irrigation, we will say a few words as to the dis- 
 advantages of the system, which are chiefly : 1st, that the 
 cost of partial distribution prevents the profitable application 
 of the sewage to any but grass land ; 2nd, that a vast 
 amount of sewage is applied to land when it does not need it ; 
 3rd, that owing to the dilution, of the sewage with the 
 surface water, its application in wet weather may be positively 
 injurious. But it will be remarked : first, that these disadvan- 
 tages only touch the farmer and not the sanitary reformer; 
 and secondly, the success in an economic point of view of the 
 system in some places proves that, however much these dis- 
 advantages may detract from the benefits to be derived from 
 the application of sewage to land, irrigation can be success- 
 fully carried on in spite of them. In fact, the first difSculty 
 may be got over by laying down the farm to be sewaged almost 
 entirely with grass crops, which, as long as hay and beef and 
 milk continue to be in large demand, must always be a profit- 
 able crop. The second disadvantage can only be moderated by 
 
 D 2 
 
36 lEEIGATION". 
 
 the treatment of a proper area of land and a judicious dis- 
 tribution of the liquid sewage, and even this may be greatly 
 diminished, if not entirely done away with, by not permitting 
 the surface-water to flow into the drain with the sewage; 
 a system which is already recommended [see Baleman, Report 
 on Sewage of Oxford, 1857, and Times, Jan. 2, 1868, Letter 
 on Sewage, by Gilbert Child] in many quarters and for many 
 reasons ; at Tottenham, for instance ; and at the Broadmoor 
 Asylum, under the auspices of Mr. Menzies. There is indeed 
 another disadvantage in the application of raw sewage to 
 land, namely, that in course of time the solid particles are 
 left on the surface, interfering with the proper growth of the 
 plant and giving off an offensive odour. The remedy for 
 this is the separation of the suspended matter and deodoriza- 
 tion of the sewage, as is now done to a certain extent at 
 Croydon, but which appears to be effected in the most satis- 
 factory manner by the phosphate of alumina, which, completely 
 deodorizing the sewage, renders the effluent water as rich in 
 manurial materials as the raw sewage. 
 
 It would be beside our plan to give a detailed account of 
 the various experiments and analyses connected with sewage 
 irrigation, but an exceedingly interesting analytical exposS 
 of the whole system, based upon experiments conducted at 
 Eugby in the year 1861, is to be found in 2 S. U. C, 1861, 
 pp. 23-37, and Appendix VHI., pp. 88-133. It wiU be sufB- 
 cient for the purposes of the present work to quote the Con- 
 clusions based upon these experiments and analyses. 
 
 1. By the application of large quantities of dilute town 
 sewage to permanent meadow land dui'ing the spring and 
 summer months, there was obtained an average increase of 
 about 4 tons of green grass (which, owing to the lower pro- 
 portion of dry substance in the sewaged grass, was equal to 
 only about three-fourths of a ton of hay) for each 1000 tons 
 of sewage supplied, until the amount of the latter approached 
 
IRRIGATION. 37 
 
 the rate of about 9000 tons per acre per annum. The largest 
 produce obtained was about 33 tons of green grass per acre. 
 The period of the year over which an abundance of green 
 food was available was, with the largest amounts of sewage, 
 between five and six months. 
 
 2. Oxen tied up under cover and fed on cut green grass 
 alone, whether sewaged or unsewaged, gave a far lower rate 
 of increase than the average obtained by animals fed on 
 ordinary good fattening food ; but when, for a few weeks, oil- 
 cake was given in addition to the grass, they yielded a good 
 average rate of increase. 
 
 8. Cows tied up under cover, and fed on cut green grass 
 alone, after previously receiving oil-cake, fall off considerably 
 in their yield of milk, and about equally whether the grass 
 was sewaged or imsewaged. The cows on unsewaged grass 
 consumed more food and gave more milk in relation to their 
 weight than on sewaged grass ; but the amount of milk 
 yielded for a given amount of fresh food consumed was 
 almost the same in the two cases, though in proportion to the 
 dry or solid matter which the food contained, the sewaged"* 
 grass yielded considerably more milk than the xmsewaged. 
 Milk to the gross value of 32Z. per acre was obtained where 
 the largest quantity of sewage was applied. The gross value 
 of the milk from the increased produce of each 1000 tons of,' 
 sewage was between 51. and 61. 
 
 4. The composition of the Eugby sewage water varied 
 very much during the course of the season, being much 
 more concentrated during the drier months. On the average 
 over about seven months, 1000 tons of sewage contained 
 about 21|- cwt., or little more than 1 ton of solid matter, 
 about 212 lbs. of ammonia, or about as much as is contained 
 in 11 cwt. of Peruvian guano, and probably represented the 
 excrements of twenty-one or twenty-two individuals of a 
 mixed population of both sexes and all ages for a year. This 
 
38 lEEIGATIOjr. 
 
 average composition agrees very closely with that wliicli 
 published analyses indicate for the sewage of London. 
 
 5. On the average the sewaged grass contained, as cut, a 
 considerably lower proportion of dry or solid substance than 
 the unsewaged, but the dry substance of the sewaged grass gene- 
 rally contained a higher proportion of nitrogenous compounds. 
 
 6. Analysis shows very little difference in the quality of 
 the milk yielded respectively from sewaged and unsewaged 
 grass. The difference in composition, such as it is, is slightly 
 in favour of the milk from unsewaged grass when grass was 
 given alone, and slightly in favour of the sewaged grass when 
 oil-cake was given in addition. [2 S. U. G., pp. 36-37.] 
 
 Some experiments were made in applying sewage to oats, 
 which appear to have been very successful [3 S. U. 0., p. 78] ; 
 but various circumstances seem to have unduly favoured the 
 crops, and the results are not to be taken as indicating what 
 might be expected in average seasons. It seems probable, 
 however, that an application at the proper time of about 
 500 tons of sewage per acre to arable land might be attended 
 with the most satisfactory results, the real difficulty being the 
 expense and impracticability of an intermittent system of 
 distribution. Indeed Mr. Eawlinson considers that the 
 expense of distributing 500 tons of sewage by the hose-and- 
 jet system would be greater than that of distributing 5000 tons 
 by the open-channel plan. [Duthie, Utilization of Towns' 
 Sewage, p. 19.] In the third Eeport, S. U. C, 1865, pp. 5-28 
 and 51-65, and Appendix I., may be found the details of 
 further experiments at Eugby during the years 1861-2-3, 
 which are most interesting, and should be carefully read by 
 all who are studying the subject of sewage irrigation ; but as 
 no new principle appears to have been evolved in the course 
 of these experiments, we content ourselves with referring 
 the reader to the Eeport for the details, merely quoting the 
 summary to be found in pp. 73-74 of the Eeport. 
 
 1. As there is a daily supply of sewage the year round 
 
IRRIGATION. 39 
 
 wUcli, on sanitary and engineering grounds, it is essential to 
 dispose of as soon as it is produced ; and as passing it over 
 tte land is the best mode, both of purifying and utilizing it, 
 it should be employed for purposes of irrigation, and be 
 applied in winter when of comparatively little value, as well 
 as in summer when of more. 
 
 2. Italian Bye-grass. — By the application of sewage to 
 grass land during the winter months a very early cut or bite 
 of green food may be obtained ; but the amount of increased 
 produce due to the winter application is comparatively small 
 for the amount of sewage employed. 
 
 3. By means of sewage irrigation the period during which 
 an abundance of green food was available was extended con- 
 siderably at the end as well as at the beginning of the seasons, 
 and the more so the larger the quantity of sewage applied, 
 almost up to the highest amount employed — 9000 tons per 
 acre. 
 
 4. One of the experimental fields gave much less produce 
 per acre without sewage than the other, and analysis showed 
 its soil to be much less naturally fertUe, but it gave fully as 
 much produce per acre under the influence of liberal dressings 
 of sewage as the naturally more fertile soil. 
 
 5. Taking the average over three years, and in the twol 
 fields, the amount of produce obtained without sewage was 
 about 9J tons of green grass per acre per annum, equal to 
 about 3 tons of hay ; and with 3000, 6000, and 9000 tons of 
 sewage per acre per annum, the amounts were respectively 
 22^, 30J, and 32| tons of green grass, equal respectively 
 (reckoned according to the percentage of dry substance in 
 each) to about 5, 5f , and 6 J tons of hay. 
 
 6. The largest quantities of produce per acre were obtained 
 in the third year of the experiments and with 9000 tons of 
 sewage per acre per annum, namely, in one field 35 tons, and 
 the other 37 tons of green grass, equal respectively about 
 6 tons 12f cwt. and 7 tons 1 cwt. of hay. 
 
40 lEEIGATION. 
 
 7. The average increase obtained for every 1000 tons of 
 sewage was, when 3000 tons per acre per anntim were applied, 
 4 tons 21 cwt. ; and when 9000 tons were applied, 3 tons 
 3j cwt. of green grass. 
 
 8. The amount of increase per acre was the greater, the 
 greater the quantity of sewage applied, up to 9000 tons per 
 acre; but the amount of increase of produce obtained for 
 a given amount of sewage was the less where the greater 
 amounts were applied. 
 
 9. Experiments with rye-grass were made in one season 
 only; sewage was not applied until the end of April, and 
 comparatively small quantities were put on. The results so 
 obtained indicated much about the same amount of increase of 
 produce for a given amount of sewage as for meadow grass. 
 
 10. When cut and given to fattening oxen tied up under 
 cover, more sewaged than unsewaged grass, reckoned in the 
 fresh or green state, was both consumed by a given weight of 
 animal within a given time, and required to produce a given 
 weight of increase ; but of real dry or solid substance, less of 
 that of the sewaged than of the unsewaged grass was required 
 to produce a given effect. 
 
 11. When cut grass was given alone, the result was very 
 unsatisfactory ; but when oil-cake was given in addition, the 
 amount of increase upon a given weight of animal in a given 
 time, and for a given amount of dry substance of food con- 
 sumed, was not far short of the average result obtained when 
 oxen are fed under cover on a good mixed diet. 
 
 12. The money return, whether reckoned per acre, or for 
 a given amount of sewage, was much less with fattening- 
 oxen than with milking-cows. 
 
 13. When cows were fed on sewaged or unsewaged grass, 
 as much as they chose to eat, a given weight of the animal 
 was more productive both of milk and increase, but especially 
 of milk, on the unsewaged than on the sewaged grass. 
 
 14. From a given weight of unsewaged grass reckoned in 
 
lEEIGATION. 41 
 
 the fresli or green state, more milk was produced than from 
 an equal weight of fresh sewaged grass ; but a given weight 
 of the dry or solid substance supplied in sewage grass was 
 on the average more productive than an equal weight supplied 
 in unsewaged grass. 
 
 15. The milk-producing quality of the grass was very 
 different in different seasons, and at different periods of the 
 same season ; it was very inferior in the wet and cold season 
 of 1862, and towards the close of the seasons as compared 
 with the earlier periods. It appears probable that Italian 
 rye-grass deteriorates less towards the end of a season than 
 meadow grass. On the average, about six parts by weight of 
 fresh grass yielded one part by weight of milk. 
 
 16. By the aid of sewage, the time that an acre would keep 
 a cow and the amount of milk yielded from the produce of 
 an acre were increased between three and four fold. 
 
 17. So far as the results of the experiments afford the 
 means of judging, it is estimated that with an application of 
 5000 tons of sewage per acre per annum to meadow land, an 
 average gross produce of not less than 1000 gallons of milk 
 per acre per annum may be expected. 
 
 18. In experiments conducted with Italian rye-grass (but 
 in one season only), more milk was obtained by the use of a 
 given amount of sewage applied to it than to meadow land. 
 
 19. With an application of about 5000 tons of sewage per 
 acre per annum, an average grass return of from 30Z. to 35Z. 
 per acre in milk, at 8d. a gallon, may be anticipated. 
 
 It must be well known to everyone who is interested in 
 the utilization of sewage, that the ammonia contained in it 
 constitutes its most valuable manurial quality, and we have 
 already seen how the various systems of chemical precipita- 
 tion have failed to secure the volatile substance ; and it 
 becomes a question, in considering the advantage of the 
 irrigation system, to see how far this ammonia is liable to be 
 wasted by the conveyance of the liquid sewage in open con- 
 
42 lEEIOATION. 
 
 duits ; a mode of distribution whicli must of course greatly 
 diminish the expense and increase the practicability of all 
 irrigation operations. The experiments have been most 
 satisfactory, and show that while in twenty-four hours the 
 loss of ammonia is scarcely appreciable, after three days 
 the proportional loss amounts to little over thirteen per 
 cent. Another extremely satisfactory fact connected with 
 this loss of ammonia is that when sewage becomes putrid 
 the ammonia which it contains is diminished in quantity, so 
 it becomes the interest of the farmer as well as the public to 
 apply the sewage before it becomes offensive. For detailed 
 account of the experiments, see 1 E. P. C, 93-94. 
 
 The disposal of sewage by means of irrigation is as old as 
 it is simple and natural. As early as the year 1561 there 
 was a sewage farm near Edinburgh, and the irrigation of the 
 celebrated Craigentinny meadows was begun before the year 
 1760. The sewage of Edinburgh is still applied to these 
 meadows with great success and profit, and those who desire 
 a full and detailed account of the works and operations gene- 
 rally, will find a very interesting account by Mr. McPherson, 
 engineer to the city of Edinburgh, quoted in the Tottenham 
 Beport, pp. 72-80 ; 3 S. U. G., p. 198, and 1 B. P. C, p. 74. 
 There appears to be a great waste of sewage, owing to the 
 insufficient area of the land under treatment, and many im- 
 provements might be made in the formation of the channels, 
 yet the success of the works in a sanitary point of view is 
 most encouraging, and the profits derived from the crops 
 almost incredible ; the crops of rye-grass fetching from 251. 
 to 361. per acre. The lower end of the Craigentinny estate 
 was simply sea-shore, until the sewage was applied to it ; it 
 is now as fertile as the rest of the farm, getting richer and 
 richer every year, notwithstanding the enormous crop annually 
 taken off it. 
 
 The two most successful sewage farms in the South of 
 England are Norwood and Croydon, the clay land at the 
 
lERIGATION. 43 
 
 former place appearing to be equally successful in purifying 
 tlie sewage as the light porous soil of Croydon. As to tlie 
 value of differently constituted soils, see 1 B. P. C, pp. 65-70. 
 It must always be borne in mind that the plant or vegetation 
 has infinitely more to do with the purification of the sewage 
 than the nature of the soil itself. As to the relative success 
 of the works at Croydon and Norwood, see Tott. Beport, 
 pp. 80-90, and 1 B. P. C, pp. 85-87. 
 
 As to Barking, where a farm of about 220 acres has been 
 laid out by the Metropolitan Sewage Eeclamation Company, 
 under Mr. Martin, see Tott. Bep., 90, and 1 B. P. C, 76. The 
 land was cropped with early carrots, onions, parsnips, po- 
 tatoes, and mangold, as well as rye-grass, and the agricultural 
 result appears to have been most satisfactory, the value of 
 the crops in some instances reaching 381. per acre. At Alder- 
 shot, again, the best cabbages that come into the London 
 market are said to be grown on the sewage farm. [Tott. Bep., 
 93, and 1 B. P. G., 77.] 
 
 But perhaps the irrigation system has been carried out 
 with the greatest success at Croydon. The soil and " lie of 
 the land " are most favourable for the adoption of the system, 
 and while citing Beddington meadows as an example of the 
 advantages of the irrigation process, it is not to be supposed 
 that the results could be quite so favourable in every locality, 
 though an examination of the comparative table, 1 B. P. C, 
 94-95, will show that in many other places the results have 
 been nearly as satisfactory. The soil at Beddington is open, on 
 a gravelly subsoil, with just sufficient slope to render easy the 
 distribution of the liquid sewage over and through it, and 
 there is just sufficient fall between the top and bottom of the 
 farm to allow the tail water of the upper fields to be spread a 
 second time over the fields below before it drains finally away. 
 The works now in the hands of the local authorities were 
 planned by Mr. Baldwin Latham, whose admirable letter to 
 the ' Echo,' Sept. 29, 1871, will give as good an account of 
 
44 lERIGATION. 
 
 the past and present state of Croydon as it is possible to have 
 in a few words. He says : — 
 
 " Before the year 1849 Croydon was governed by various 
 authorities, each having a separate jurisdiction. Soon after 
 the passing of the Public Health Act of 1848 it was adopted 
 in Croydon, and a Local Board was established in August, 
 1849. Previously to this period Croydon had long been 
 known for its unhealthiness. An Act of Parliament was 
 passed in 1809, to enable the Archbishop of Canterbury to 
 alienate the site of the Palace at Croydon, the preamble of 
 the Bill stating that the site was ' damp and unwholesome.' 
 Before the formation of the Local Board little or nothing had 
 been done in the way of alleviating the sufferings which had 
 arisen from sanitary neglect. No wonder, therefore, that the 
 rate of mortality in 1848, when the population slightly ex- 
 ceeded 19,000, was upwards of 28 per thousand, and that the 
 average rate of mortality for seven years before the com- 
 pletion of the first operations of the Local Board, was over 
 23 per thousand. 
 
 " In the matter of the disposing of the sewage the authori- 
 ties were, at one time, very unfortunate. The first operations 
 for purifying the sewage consisted in the construction of filter 
 works for filtering it through charcoal and other materials. 
 These works were erected near the town, but even before the 
 whole works of sewerage were complete their insufficiency 
 became apparent, as numerous complaints were lodged with 
 the Board by those living on the stream as to the state of 
 pollution into which the river Wandle was being brought by 
 reason of the filtered sewage being discharged into it. Then 
 followed a series of experiments, with all kinds of material, 
 to attempt to precipitate and deodorize the sewage. Some of 
 the first chemists of the day were consulted, but it is rather 
 a significant fact that the more the money spent in deodo- 
 rizing, the greater the number of the complaints of the people 
 living lower down the stream. In fact, when the sewage was 
 
lEEIGATION. 45 
 
 discharged into the stream in its normal state it created a 
 great nuisance near the outfall, but a species of self-purifi- 
 cation took place, consequently the water lower down the 
 stream was not in a very bad state ; but when deodorizing 
 agents were used the sewage was preserved, or pickled, but 
 its noxious elements were not removed or destroyed. 
 
 " In the midst of their troubles they appealed from autho- 
 rity to authority, but could meet with no remedy or repose ; 
 at last, driven to extremities by the Court of Chancery, the 
 Local Board took a farm at Beddington on the recommen- 
 dation of the chairman, Mr. C. W. Johnson, F.E.S., upon 
 which to apply the sewage. The farm was subsequently let 
 to, and laid out by, Mr. John Marriage, and shortly after- 
 wards a second farm was taken at Norwood. Since the first 
 acquisition of land for irrigation purposes, the area has been 
 considerably increased, and the mode of treating and distri- 
 buting the sewage has undergone considerable improvement. 
 The sewage of Croydon and a portion of Upper Norwood is 
 conveyed to the Sewage Irrigation Farm at Beddington, com- 
 prising an area of 450 acres, of which about 400 acres are 
 now under sewage irrigation. The works at Norwood are in 
 the hands of the local authorities, and during last year they 
 received for the produce of 33 acres the sum of 888Z., or 
 211. per acre. These works, inclusive of outfall works, cost 
 the authorities about 2500Z. After paying rent at the rate of 
 lOZ. per acre, taxes, tithes, labour, purchase of implements, 
 seeds, &c., and the cultivation for ensuing year, there was left 
 a profit of 173Z., or a sum nearly equal to 7 per cent, on the 
 gross outlay for works. The rent paid for land is excessive, 
 for before the local authorities acquired the land for sewage 
 purposes it was let at 18s. per acre, and was considered dear 
 at that price. 
 
 " The works at Beddington have been worked from the 
 25th March, 1870, by the Croydon Farming and Irrigation 
 Company, Limited. The area they had under cultivation last 
 
46 IRRIGATION. 
 
 year was about 270 acres. The company paid the local 
 authorities of Croydon, during the year, 974Z. 10s. for rent of 
 land, and 900Z. for the sewage. The gross receipts from the 
 land were 4818Z. 2s. 2d., or about 181. per acre. The gross 
 outlay for rent, sewage, seed, labour, &c., was 4209Z. 7s. 2d. 
 The profit made in the year, after writing off about 12 per 
 cent, for depreciation, and one-sixth the preliminary expenses, 
 was 608Z. 6s. 6d. The capital called up by the company was 
 2028Z., the amount earned in the year being at the rate of 
 30 per cent, per annum. The total cost of these irrigation 
 and outfall works to the local authorities, exclusive of the 
 purchase of land, has not exceeded 8000Z. The 900Z. received 
 for the sewage would pay a dividend of 11 per cent, on this 
 outlay. 
 
 " The mode of dealing with the sewage consists, first, in 
 separating the solid faeces, sand, paper, &c., from the liquid 
 sewage. The liquid sewage alone, in the state conveyed by 
 the sewers, is applied in its fresh state to the land. When 
 sewers are perfectly constructed they discharge their contents 
 with rapidity, the sewage conveyed by such sewers having 
 the appearance of slightly dirty water, in which are suspended 
 fffical and other matters ; in this state sewage is by no means 
 very offensive, but if the sewers are not properly constructed 
 and become sewers of deposit, tlie decomposition of the feecal 
 and other matters takes place before the sewage arrives at its 
 outfall, and it is then discharged as a blackish, loathsome, 
 stinking liquid. At Croydon the solid sewage is removed 
 from the liquid before the decomposition takes place ; conse- 
 quently the sewage is comparatively sweet, and needs no 
 deodorizing. The apparatus used for the purpose of sepa- 
 rating the solid and liquid sewage consists of an upright 
 vertical revolving screen, impelled by the liquid sewage, so 
 that the liquid sewage in motion is made the motive power to 
 remove the solid sewage, just as fast and continuously as it is 
 
lEEIGATION. 47 
 
 conveyed to the outfall. The amount of solid sewage daily 
 removed at the Croydon outfall is about one-tenth of a pound 
 per head of the population contributing to the sewers, being 
 a greater amount than was found to be removed by the phos- 
 phate of alumina process recently tried at Tottenham. The 
 Farming Company are now about to manufacture this solid 
 sewage into a portable manure, worth 31. 10s. per ton. After 
 leaving the separating works, the sewage is distributed by 
 means of carriers over the surface of the land ; the area daily 
 under sewage treatment is about one-tenth of the whole farm. 
 All kinds of produce are grown with the liquid sewage, and 
 at the present time may be seen on the land crops of man- 
 golds, rye-grass, onions, cabbages, broccoli, celery, potatoes, 
 and parsnips, which are not to be equalled in the neighbour- 
 hood ; and so great is the repute in which the produce is held 
 in the open market, that buyers are known to wait to ascertain 
 if the Farm Company's carts are coming before they will 
 purchase from other persons. The health of the stock on the 
 farm is remarkably good ; when disease has been imported it 
 has taken the mildest type, and although the Farm Company 
 have had a large number of cattle on their farm, they have 
 not lost a single head from disease. The milk produced by 
 the dairy stock is very rich, often containing 16 per cent, of 
 cream, and is sold, unadulterated, to large customers at lOd., 
 and to small customers at Is. per gallon. 
 
 " As regards the effect of irrigation on the purification of 
 sewage, the reports of the Elvers Commissioners, who have 
 made repeated analyses of the effluent water, show that the 
 system, properly managed, is a perfect purifier of sewage. 
 The Royal Elvers Commissioners also investigated the matter, 
 and took samples of purified Croydon sewage and river water 
 for analysis, and gave the results, showing that the river 
 Wandle at Mitcham, after receiving Croydon purified sewage, 
 was purer than the Thames above Eeading. With regard to 
 
48 IRRIGATION'. 
 
 the influence of sewerage and sewage irrigation works on 
 public liealtli, the evidence on this point is conclusive. At 
 the present time the population of Croydon is close upon 
 60,000 ; the average rate of mortality, for ten years past, has 
 been under 19 in the thousand; and — what is still more 
 remarkable — the districts in closest contiguity with the 
 irrigation works have had the lowest death rate." 
 
 With regard to the last paragraph in the letter, see Eep. 
 Social Science Meeting at Bristol, Oct. 2, 1869, a paper by 
 Dr. A. Carpenter, whence we take the following statistics. 
 Death rate for Norwood population, about 5000, for six 
 years : — 
 
 1863 .. . 
 
 . .. 18-76 
 
 1864 .. . 
 
 . .. 18-89 
 
 1865 .. 
 
 .. 18-17 (Sewage Farm established) 
 
 1866 .. . 
 
 . .. 15-34 
 
 1867 . . . 
 
 . .. 14-21 
 
 1868 .. . 
 
 . .. 12-07 
 
 See also 1 E. P. C, 91, as to the entire absence of smell 
 or nuisance at the farm at Beddington ; and at Barking, Tott. 
 Eep., p. 93. 
 
 Having now concluded what is, I hope, an impartial review 
 of the principal systems of sewage utilization that have been 
 tried in this country, I bring this little work to a close, for 
 it is no part of my plan to offer any further conunent upon 
 the various schemes than is necessary for properly explain- 
 ing their mode of working. Some systems have necessarily 
 occupied more of our time than others, but in every instance 
 a reference will be found to some fuller and more detailed 
 accoimt than was possible in a handbook like the present. 
 As such, I trust it may be of use in directing and assisting 
 the labours of those sanitary reformers whose efforts are now 
 attracting so large a share of public interest, and whose 
 success is so ardently to be desired by all. 
 
( 49 ) 
 
 APPENDIX I. 
 
 A List of Places ik Ensland where Sewage Opekations have 
 
 BEEN CARKIED ON WHICH HAVE NOT BEEN EEFERKED TO IN THE 
 COURSE OF THE FOREGOING WoRK, WITH KeFERENOES TO REPORTS 
 AND OTHER SOURCES, WHERE A FULL DESCRIPTION OF THE WoRK 
 IS TO BE FOUND. 
 
 Aldershot 
 
 . .. IE. P. C, 77. 
 
 AsHB¥-DE-LA-ZorCH . 
 
 2 S. U. C, Appendix VII., pp. 75-87. 
 
 Banbdet 
 
 . . . 1 R. P. C, 80. 
 
 Barking 
 
 . .. IE. P. C, 75. 
 
 Bedford 
 
 . . . 1 E. P. C, 83. 
 
 BiLSTON 
 
 . .. 2 S. U. C, pp. 75-87. 
 
 Birmingham 
 
 .. Ditto, and Birmingham Report, 1871. 
 
 Burt 
 
 jEeport of British Association, 1870, pp 
 • ■■ 1 49-72. 
 
 Cambridge . . 
 
 . .. Ditto. 
 
 Carlisle 
 
 . . . 1 R. P. C, 78. 
 
 Chelmsford . . 
 
 . . . 2 S. U. C, pp. 75-87. 
 
 Cheltenhatvt 
 
 . . . Ditto. 
 
 Clifton 
 
 . Ditto. 
 
 Coventry . . 
 
 . . . Ditto. 
 
 Ely 
 
 . .. Ditto. 
 
 Leicester 
 
 . .. Ditto. 
 
 Leith 
 
 . . . 3 S. U. C, Appendix V. 
 
 Ldton 
 
 . .. 2 S. U. 0., pp. 75-87. 
 
 Norwood 
 
 . .. IE. P. C, 85. 
 
 Penrith 
 
 , . 1 R. P. C, 79. 
 
 Plymouth 
 
 .. 2 S. IT. C, pp. 75-87. 
 
 Preston 
 
 .. Duthie, Utilization of Sewage, pp. 31-39 
 
 
 /Report of British Association, 1870, pp 
 m) .. 1 49_72 
 
 Romford (Breton's far 
 
 Rugby 
 
 . .. 1 R. P. C, 79, and 2 S. U. C, pp. 75-87 
 
 Steoud 
 
 . . , 2 S. U. C, pp. 75-87. 
 
 Uxbridqe 
 
 . . . Ditto. 
 
 Warwick 
 
 , 1 R. P. C, 82. 
 
 Woking 
 
 . , , 1 R. P. C, 89. 
 
 Worksop 
 
 .. 2 S. U. C, pp. 75-87. 
 
 Worthing . . 
 
 . .. IR. P. C, 82. 
 
 E 
 
( 50 ) 
 APPENDIX II. 
 
 SMOKE DEAINAGE. 
 
 A VERT interesting little pamphlet was published at Man- 
 chester in the year 1857, by Mr. Peter Spence, entitled 
 ' Coal, Smoke, and Sewage.' The system advocated by Mr. 
 Spence was brought into public notice by some letters which 
 appeared in ' The Times,' ' Pall Mall Gazette,' and ' Daily 
 News' during the month of December, 1871, upon the ad- 
 visability of carrying the smoke from our house fires through 
 the drains, with a view of both deodorizing the sewage and 
 purifying the atmosphere of our great towns. It appears that 
 the amount of ammonia produced and wasted by being thrown 
 into the atmosphere in the burning of coal is something 
 enormous. Mr. Spence (p. 30) considers 22 lbs. of ammonia 
 for every ton of coal consumed a very low estimate ; and, 
 taking 2,000,000 tons of coal as the quantity annually con- 
 sumed at Manchester, we have nearly 20,000 tons of sulphate 
 of ammonia, which would be deposited in the smoke drains. 
 As the value of this sulphate of ammonia for manure is at 
 present about 20Z. per ton, some idea may be formed of the 
 value of this deposit, and Mr. Spence's figures show the most 
 golden results. There would be no doubt a very great diffi- 
 culty in adopting any system of smoke drainage in some of 
 our large towns ; in fact, a complete revolution would have 
 to be worked in our house and street architecture, but if only 
 half the practical advantages dilated upon by Mr. Spence 
 could be guaranteed to any town willing to undergo the pro- 
 cess of transformation, I am sure all would willingly submit 
 to a vast amount of preliminary annoyance for the sake of the 
 new life and health to be obtained 
 
( 51 ) 
 
 APPENDIX III. 
 
 MR. BAZALGETTBS PROPOSED SYSTEM. 
 
 As to Mr. Bazalgette's great scheme for purifying the Thames 
 between London and Windsor from sewage, a very imperfect 
 notion is all that can be given at present. A few years ago, 
 various Acts were passed to prevent the pollution of the 
 water by allowing sewage to flow direct into the river, 
 and the Eoyal Commissioners of Water Supply, in their 
 Eeport of 1869, recommended the Thames as one of the per- 
 manent sources of the water supply of the metropolis. It 
 seems that since the passing of the various Thames Naviga- 
 tion Acts, the inhabitants of the town and villages of the 
 valley of the Thames have experienced great difficulty in dis- 
 posing of their sewage, or rather that no system of sewage 
 utilization has met with sufficient favour in their various 
 localities as to lead to its permanent adoption : and in order 
 to carry away the imited bulk of the sewage to a place where 
 it may be conveniently and safely dealt with, Mr. Bazalgette, 
 the chief engineer of the Metropolitan Board of Works, has 
 devised a scheme which is to be submitted to the considera- 
 tion of Parliament this session. It would be idle to criticize 
 a scheme of which we know so little ; but it certainly appears 
 to be bold and comprehensive, and we hope it may be satis- 
 factorily worked out. The area to be dealt with consists of 
 about 100 square miles, containing a population of over 
 300,000 persons. Mr. Bazalgette proposes, in the first place, 
 to purchase and adapt about 3000 acres of almost unculti- 
 vated land, between Woking and Bagshot, which it appears 
 may be obtained for a comparatively small sum of money. 
 To this tract of land it is proposed to apply the sewage 
 
52 APPENDIX. 
 
 much upon the same principle as that at present in success- 
 ful operation at Croydon [see ante, p. 46], and of which no 
 further mention need he made in this place. The sewage 
 would be conveyed by natural gravity from Acton, Chiswick, 
 Ealing, Hanwell, Brentford, Isleworth, Barnes, Mortlake, 
 Kcw, Eichmond, Twickenham, Mitcham, Merton, Maiden, 
 Mordeu, Wimbledon, Teddington, Kingston, Hampton, Esher, 
 Thames Ditton, Moulsey, Walton, and Weybridge, to Hamp- 
 ton, where it would be conveyed by powerful puiuping engines, 
 and again flow by gravity till it arrived at Chertsey, receiving 
 ou its route the drainage from Southall, Norwood, Hasten, 
 Hounslow, Sunbury, Hunworth, Laleham, and Shepperton. 
 Other main sewers, commencing at Eton and Windsor, would 
 bring the drainage from Windsor, Datchet, Horton, Old 
 Windsor, Colebrook, Egham, and Staines, also by gravity 
 alone, to Cuertset, where a regulating reservoir would be 
 formed, and where a second pumping station would raise the 
 united voliune to a reservoir at the head of the proposed 
 sewage farm, on, to, and over which the entire sewage would 
 ultimately flow. The total cost of this gigantic combination 
 is estimated by Mr. Bazalgette at less than 700,000Z. Owing 
 to the prohibition against the mixing of storm water in the 
 sewage, the rainfall, except in particular instances, would be 
 excluded from the local sewers. To carry out this plan, says 
 'The Times ' (February 1, 1872), a Board of Commissioners 
 elected by the parishes interested, and invested with all 
 necessary powers, is proposed. The promoters allege that 
 the scheme would answer two ends — relief from the penalties 
 of the Thames Navigation Acts, and a cheap and effectual 
 mode of disposing of sewage at a distance. The cost is such 
 as to compare favourably with that of other plans, and would 
 be rapidly reduced, and ultimately extinguished, leaving a 
 large profit to the credit of the ratepayer. 
 
( 53 ) 
 
 APPENDIX IV. 
 
 ON THE LAW CONNECTED WITH THE UTILIZATION OE 
 SEWAGE. 
 
 Up to the year 1865, sewage operations could only be carried 
 on in towns or parishes in which the Public Health and 
 Local Government Acts had been adopted ; and previous to 
 1867, all sewage operations in towns or districts where those 
 Acts had been adopted could only be carried on under the 
 provisions and in the manner prescribed by them. The 
 Sewage Utilization Act of 1867 [30 and 31 Vic, c. 113] at 
 present enables all parishes or districts to carry on the neces- 
 sary operations for the removal and utilization of their 
 sewage without adopting the Public Health Acts of 1848 and 
 1858, which in some places may for various reasons be con- 
 sidered undesirable. 
 
 Sewage operations may now therefore be carried on both 
 in places where the Public Health and Local Government 
 Acts have been adopted, under the provisions and in the 
 manner prescribed by those Acts, modified and enlarged 
 by the Sewage Utilization Acts of 1865 and 1867; and in 
 places where the Public Health and Local Government Acts 
 have not been adopted, by virtue of the Acts of 1865 and 
 1867 alone. In each case, of course, the powers and provi- 
 sions are modified and controlled by subsequent legislation. 
 
 It would be out of place at present to do more than indi- 
 cate the Acts of Parliament to which reference must be made 
 by all who seek to learn how far and in what direction they 
 may go in their sewage utilization operations ; and the pre- 
 sent law upon the subject will be found touched upon in 
 
54 APPENDIX. 
 
 Glen's ' Laws relating to Public Health and Local Govern- 
 ment, 1869 ;' ' The New Sanitary Laws, 1871,' by W. G. and 
 E. Lumley ; ' The Sanitary Acts,' by W. H. Michael, and 
 other books. 
 
 It may be added that a thorough reform in the law con- 
 nected with this subject is anticipated this session of Parlia- 
 ment, to say nothing of Mr. Stansfeld's BOI for establishing 
 a local authority for sanitary matters in every parish or dis- 
 trict. Pending further legislation, therefore, we have re- 
 stricted our remarks on the present law to these few words. 
 
 Some of the most recent cases of interest connected with 
 sewage operations are: Brown, App., Eussell, Eesp., and 
 Francomb, App., Freeman, Eesp., L. E., 3 Q. B. 251 (as to 
 nuisance) ; Lord Derby v. Bury Lnprovement Commissioners, 
 L. E., 3 Ex., 121 (ditto) ; Goldsmid v. Tunbridge Wells Im- 
 provement Commissioners, L. E., 1 Eq., 161 (injunction) : on 
 appeal, L. E., 1 Ch., App. 349 ; Crossley v. Lightowler, 
 L. E., 3 Eq., 279 (pollution of river); on appeal, 2 Ch. 
 Ap. 478. 
 
( 55 ) 
 
 APPENDIX V. 
 
 HTLLES PROCESS. 
 
 In Hille's process, which has been tried with great success 
 at Wimbledon, the sewage is treated with lime, tar, salts of 
 magnesium, and the products arising from the calcination 
 of the lime, and by other chemicals, according to locality. 
 The eflBuent water is afterwards filtered on the downward 
 intermittent principle [ante, p. 31) ; the results thus obtained 
 have been found to reach the standard of purity required by 
 the Thames Conservancy, and also that mentioned in the 
 Eeports of the Eivers Pollution Commission (ante, p. 7). 
 
 The disinfecting compound is applied to ordinary town 
 sewage in the proportion of about 1 in 1000 of sewage, as it 
 flows into the works. 
 
 The thorough amalgamation of the chemical compound and 
 the sewage here takes place, after which the whole is allowed 
 to accumulate in the deposit tanks, where nearly the whole of 
 the suspended matters are deposited, together with a con- 
 siderable quantity of the various matters held in solution. 
 
 After the sewage water has risen to a height of two-thirds 
 of the total depth of the deposit tank, the liquid is drawn off 
 by means of a floating outlet through a regulating valve. 
 This outlet is formed of strong galvanized wire, the interior 
 of cage being filled with vegetable charcoal. 
 
 The maximum speed of filtration is at the rate of one 
 gallon to each superficial yard of filter, which is so designed 
 that the fi[ltering materials have time for thorough and com- 
 plete aeration. 
 
 Into the filtered effluent water carbonic acid gas is forced. 
 
56 APPENDIX. 
 
 and complete purification takes place. This gas is a waste 
 product of the lime whicli is burned on the premises. 
 
 The outlet chamber is provided with a second floating 
 outlet with a governor regulating valve. The water is then 
 in such condition as to be admissible into rivers. 
 
 The works, and everything connected therewith, are in 
 duplicate, and may be used alternatively. 
 
 The deposited sewage residue is removed daily from the 
 tanks, through valves, into a timnel constructed in the divi- 
 sional wall, and raised by the steam-engine into the hydro- 
 extractors ; from thence the semi-dried sewage is placed on a 
 drying-kiln, the gases evolved being drawn off and consumed 
 in the boiler's furnace. 
 
 It is contended that the whole process can be worked 
 without the least nuisance, and that the works may be con- 
 structed in populated parts of towns without injury to the 
 health of the inhabitants. 
 
 The value of the sewage precipitate will vary in difierent 
 districts, but it is calculated to realize on an average 26s. per 
 ton in its raw state. 
 
( 57 ) 
 
 INDEX. 
 
 A. PAGE 
 
 A B C system, or Sillar's patent 25-29 
 
 „ experiments on London sewage with .. .. 28-29 
 
 Aldershot, sewage operations at 43,49 
 
 Ammonia, loss of, from putrescence of sewage 42 
 
 „ amount of, in coal smoke , 50 
 
 Amount of pollution of river water 3 
 
 Arable land, application of sewage to 38 
 
 Ashby-de-la-Zoucli, sewage operations at 49 
 
 B. 
 
 Banbury, sewage operations at 49 
 
 Barking, sewage farm at 43-49 
 
 Bateman, report on sewage at Oxford 36 
 
 Bazalgette, great scheme for purifying the Thames ,. .. 51-52 
 
 Beddington 48-48 
 
 Bedford, sewage operations at 49 
 
 Bilston, sewage operations at 49 
 
 Birmingham, „ 49 
 
 Blackburn, treatmient of sewage at 18 
 
 Blyth's process 20 
 
 Bradford, treatment of sewage at 19 
 
 Broadmoor Asylum, „ 36 
 
 Brodie, Sir Benjamin, on pollution of water 4 
 
 Buchanan, Dr., on advantages of Moule's system 14 
 
 „ on water pollution at Guildford 4 
 
 Bury, treatment of sewage at 49 
 
 O. 
 
 Cambridge, sewage operations at 49 
 
 Carlisle, „ 49 
 
 Cases, recent, in courts of law as to sewage operations . . . . 54 
 
 Charcoal, purification of sewage by 30 
 
 Chelmsford, sewage operations at 49 
 
 Cheltenham, „ 49 
 
58 INDEX. 
 
 PAGE 
 
 Child, Gilbert, letters on Milaa system 12,36 
 
 Chinese, utilization of sewage by 9 
 
 Clifton, sewage operations at ■ 49 
 
 Cornbrook, pollution of river 3 
 
 Coventry, sewage operations at 49 
 
 Craigeutinny Meadows, irrigation of 42 
 
 Croydon, sewage farm at 43-48 
 
 D. 
 
 Denton, Bailey, intermittent downward filtration 31-32 
 
 E. 
 
 Baling, treatment of sewage at 31 
 
 Edinburgh, „ 42 
 
 Effluvia, absence of, on sewage farms 48 
 
 Ely, sSwage operations at 49 
 
 Eureka system, description of 12 
 
 F. 
 
 Farr, Dr., evidence on pollution of vfater 4,6 
 
 Filtration 30 
 
 Fish, how influenced by sewage pollution 8 
 
 Frankland, Dr., evidence on pollution of water 4 
 
 a. 
 
 Grarnet, W. J., experiments at Lancaster 16 
 
 Goux's system, description of 13 
 
 Grass, comparative value of sewaged and uusewaged .. .. 37-41 
 
 Guildford, cause of outbreak of typhoid fever at, 1867 .. 4 
 
 H. 
 
 Hille's process, description of 55-56 
 
 Hofmann and Frankland, Messrs., on the best precipitants .. 20 
 
 Holden's process ,. . . 19 
 
 Hose and jet, irrigation by 33 
 
 Hyde, treatment of sewage at 12 
 
 I. 
 
 Ingredients, valuable, in sewage 35 
 
 Irrigation 33_48 
 
 „ disadvantages of 35-36 
 
 „ antiquity of 42 
 
 Irwell, pollution of 2 
 
 Italian rye-grass, suitability for sewage irrigation 39 
 
INDEX. 59 
 
 L. PAGE 
 
 Law connected with sewage utilization 53-54 
 
 Lawes and Gilbert, Messrs., analysis of manure produced by 
 
 the Eureka process 12 
 
 Leamington, A B experiments at 27 
 
 Leicester, treatment of sewage at 18-27,49 
 
 Leith, sewage operations at 49 
 
 Lenk's process 20 
 
 Letheby, Dr., evidence on water pollution 4 
 
 Lime process 18 
 
 „ and chloride of iron, experiments with 19 
 
 Lombard irrigation referred to 13 
 
 Luton, sewage operations at 49 
 
 m. 
 
 Manchester, privy system at 10 
 
 Marshall, P. P., Esq., C.E., report on phosphate process .. 22 
 
 Mersey, comparative purity of 3 
 
 " Midden " towns, strength and volume of sewage in .. .. 10 
 
 Milan, system in operation at 12-18 
 
 Milk, effect of sewage on amount of 37, 41 
 
 Modes of detecting impurity in water 5 
 
 Moule's earth-closets 13-16 
 
 N. 
 
 Northampton, treatment of sewage at 19 
 
 Norwood, sewage farm at 43, 45, 49 
 
 „ low death rate at 48 
 
 P. 
 
 Parkes, Dr., evidence on water pollution 4 
 
 Penrith, sewage operations at 49 
 
 Perchloride of iron, value of 20 
 
 Peroxide of iron used as a precipitant 21 
 
 Persalts of iron, value of, as a precipitant 20 
 
 Phosphate process 22-25 
 
 Plymouth, sewage operations at 49 
 
 Pollution of water, what should be deemed 7 
 
 Preston, sewage operations at 49 
 
 Privy and ash-pit system 11 
 
 „ water-closet compared 12 
 
 K. 
 
 Bochdale, treatment of sewage at 13 
 
 Eomford (Breton's farm), sewage operations at 49 
 
60 INDEX. 
 
 FAGB 
 
 Eoscoe, Professor, on contamination of water 5,7 
 
 Rugby 49 
 
 Eunning water, self-oxidization of 8 
 
 S. 
 
 Scott, Major-General, E.E., system of utilization 30 
 
 Simon, Mr., evidence on water pollution 4 
 
 Smoke drainage 50 
 
 Spence, Peter, system of smoke drainage 50 
 
 Stroud, treatment of sewage at 19,49 
 
 Sulphate of ammonia, experiments with 19 
 
 „ alumina, „ 20 
 
 T. 
 
 Terling, cause of outbreak of typhoid fever at, 1867 . . . . 4 
 
 Thames contamination of water above London 2 
 
 „ purificatioD, Mr. Bazalgette's great scheme .. .. 51-52 
 
 Thome, Dr., on pollution of certain wells 3,4 
 
 Throstlenest Weir, sample of polluted water at 2 
 
 Tottenham, treatment of sewage at 18,20,22 
 
 Town sewage, most profitable mode of utilizing 34 
 
 TJ. 
 
 Uxbridge, sewage operations at 49 
 
 V. 
 
 Value of human excrement 9 
 
 Voeloker's analysis of results of phosphate process . . . . 24-25 
 
 w. 
 
 Warwick, sewage operations at 49 
 
 Wimbledon camp, earth-closets at .. 14 
 
 „ Hille's process at 55 
 
 Woking, sewage operations at 49 
 
 Worksop, „ „ 49 
 
 Worthing, „ „ .. 49 
 
 London: printed by w. Clowes and sons, Stamford street and charing cross. 
 
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 Engravings, ISs. 
 
 ELEMENTARY PRINCIPLES OP CARPENTRY. 
 
 By Thomas Teedgold. Eevised from the Original Edition, and partly Re- 
 written, by John Thomas Hukst. 
 
 CONTENTS : 
 Equality and Distribution of Forces. Construction of Partitions, ScaiFolds, 
 
 Resistance of Timber. ' Staging, and Gantries. 
 
 Construction or Centres tor iiridges. 
 Construction of Floors. Coffer-dams, Slioring and Strutting, 
 
 Construction of Roofs. ', Wooden Bridges and Viaducts, Joints, 
 
 ^ , ,. ^ T^ J ^ 1 i Straps, and other Fastenings, Timber, 
 
 Construction of Domes and Cupolas. ] T hi & & 
 
 8vo, cloth, with many hundred Wood Engravings, 12s. 6d. 
 
 ILLUSTRATED HANDBOOK OF MACHINERY 
 
 AND lEO-VWOEK, with the Cost, the Working Expenses, and the Results 
 obtained in the use of Steam and Hand Cranes, Pumps, Fixed and Poitable 
 Steam Engines, and various other Machines ; with Weiglit, Measurement, 
 &c., &c. Also Prices of Tools, Iron Works, Stores and Materials required by 
 Civil and Mechanical Engineers, Merchants, and otliers ; together with 
 numerous Tables and Memoranda. By Appleby, Bros., Engineers. 
 
 Second Edition, revised with Appendix, royal 32mo, roan, 4s. Sd. 
 
 A POCKET-BOOK OF PRACTICAL RULES FOR 
 
 THE PROPORTIONS OF MODERN ENGINES AND BOILERS FOR 
 LAND AND MARINE PURPOSES. By N. P. Bdegh. 
 
 Second Edition, Revised and Corrected, post 8vo, cloth, illustrated with numerous 
 Wood Engravings, 7s. 6d. 
 
 THE ESSENTIAL ELEMENTS OF PRACTICAL 
 
 MECHANICS, based on the principle of work ; designed for Engineer'ng 
 Students. By Oliver Bybne, formerly Professor of Mathematics, College 
 for Civil Engineers. 
 
 London : E. & F. N. SPON, 48, Charing Cross.