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Cornell University Library 
 TD 741.D41 1885 
 
 Sewage disposal, ten years' experience in 
 
 3 1924 004 401 349 
 
Cornell University 
 Library 
 
 The original of tiiis 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/cu31924004401349 
 
SECOND EDITION, WITH ADDITIONS. 
 
 ft) 
 
 SE-WAGE DISPOSAL. 
 
 TEN YEARS' EXPERIENCE 
 
 (HOW FOURTEEN YEARS) 
 
 IN WORKS OF 
 
 INTERMITTEUT DOWNWARD FILTRATION, 
 
 Separately and in Combination with Surface Irrigation; 
 
 WITH NOTES ON THE PRACTICE AND RESULTS OF , 
 SEWAGE FARMING, 
 
 J. BAILEY-DENTON, 
 
 Thiriy-five years Principal Engineer to the General Land Drainage 
 and Improvement Company. 
 
 Chevalier du Merite Agricole (France). 
 
 1885. 
 
 E. & F. N. SPON, 125, STRAND, LONDON. 
 
 PRICE FOUR SHILLINGS. 
 
SECOND EDITION, WITH ADDITIONS. 
 
 SE\A/AGE DISPOSAL. 
 
 TEN YEARS' EXPERIENCE 
 
 (NOW FOURTEEN YEARS) 
 
 IN WORKS OF 
 
 INTERMITTENT DOWNWARD FILTRATION, 
 
 Separately and in Combination with Surface Irrigation ; 
 
 WITH NOTES ON THE PRACTICE AND RESULTS OF 
 SEWAGE FARMING. 
 
 J?^AILEY-DENTON, 
 
 Thirty-five years Principal Engineer to the General Land Drainage 
 and Improvement Company. 
 
 Chevalier du Merite Agricole {France). 
 
 1885. 
 
 E. & F. N. SPON, 125, STRAND, LONDON. 
 
 PRICE FOUR SHILLINGS. 
 
LONDON : 
 HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, 
 
 ST. martin's lane. 
 
INTERMITTENT FILTRATION. 
 
WORKS BY MR. BAILEY-DENTON, M. Inst. C.E.; F.G.S. 
 
 Honorary Member of the R.A.S.S. of Denmark, Sweden, and Hanover. 
 
 Land Drainage and Drainage Systems, 1854. 
 
 Underdrainage of Land ; its progress and results, 1855. (Society of Arts Medal.) 
 
 Road-making, 1857 ; Prize Essay. 
 
 The effect of Underdrainage on Arterial Channels and Outfalls, 1858. 
 
 The Discharge from Underdrainage, 1863. (Telford Medal, Inst. C.E.) 
 
 The Farm Homesteads of England, 1864. 
 
 The importance of Shelter and Covering at Homesteads in certain Districts of Great 
 
 Britain, 1865. 
 The Marshes of South Italy, 1865. 
 The Water Question, 1866. 
 Village Sanitary Economy. 
 The Agricultural Labourer, 1868. 
 Sanitary Works, 1869. 
 
 Sewage Farming, 1870. 
 
 Sewage the Fertilizer of Land, and Land the Purifier of Sewage, 1871. '' 
 
 Underdrainage and the steps to be taken to develop and maintain its effects, 1 872. 
 
 Intermittent Downward Filtration and Irrigation, 1873. 
 
 Sanitary Science applied to Towns and Rural Disfricfs, 1874; 
 
 Storage of Water, 1874. 
 
 Sanitary Engineering (a Series of Lectures given before the School of Military 
 
 Engineering at Chatham), 1876. 
 Lectures on the Water Economy of Great Britain ; on the Storage of Water ; and 
 
 on Land Drainage, given at the Royal Agricultural College, Cirencester. 
 Technical Teaching at Rural Elementary Schools, 1878. 
 
 Such of the above works as now remain in print can be obtained of Messrs. Spon, 
 12;, Strand. 
 
 Also, 
 HANDBOOK OF HOUSE SANITATION, 
 
 FOR ALL PERSONS SEEKING A HEALTHY HOME. 
 
 By Eardley Bailey-Denton, C.E., B.A., 
 32, Whitehall Place, London. 
 
PREFACE TO SECOND EDITION. 
 
 Intermittent Filtration having been somewhat prominently referred 
 to in terms of approval by the Royal Commission on Metropolitan 
 Sewage Discharge, and the treatise entitled "Ten Years' Experience in 
 Works of Intermittent Downward Filtration," published in 1880, from 
 which sundry quotations have been made, being out of print, its author 
 has determined to issue a second edition through the same publishers. 
 In order that the importance of the subject and its bearing on the 
 future treatment of sewage may be better appreciated than it could be 
 through the work itself only, the following portions of the Commis- 
 sioners' Report are here reproduced : — 
 
 "We have also alluded to a novel system of sewage treatment 
 which was first proposed in the Rivers Pollution Commissioners' 
 Report of 1870 on the Mersey and Ribble basins. This system 
 consisted simply in making the filtration through porous land the 
 principal instead of an incidental process of sewage treatment. 
 
 " In the course of investigations on various modes of sewage disposal 
 it seems to have attracted the attention of Dr. Frankland (to whom 
 the new process is ascribed) that in some cases where such filtration 
 naturally occurred the result was to purify the sewage in a remarkable 
 degree— in fact, that what were known as pure streams were often only 
 derived from sewage filtered in this manner. Hence it occurred to him • 
 to try whether a plan might not be devised by which this desirable 
 result could be brought about at will. With this view he instituted a 
 series of experiments, and established the fact that by passing sewage 
 through a suitably porous soil, not constantly but intermittently, a high 
 degree of purification could be ensured,/the object of the intermittence 
 being to aerate the filter and so give an opportunity for the purifying 
 action of the oxygen. It is explained that a filter so used is not a mere 
 mechanical contrivance, but a chemical apparatus for oxidising and thus 
 altogether transforming, as well as for separating, the filth of dirty water. 
 " The Report (that of the Rivers Commission) says : — 
 
 " ' These experiments on the filtration of sewage through various materials leave no 
 doubt that this liquid can be effectually purified by such processes, and that probably 
 any variety of porous and finely divided soil may be employed for this purpose. 
 
 " ' With a properly constituted soil well and deeply drained, nothing more would 
 be necessary than to level the surface and to divide it into four equal plots, each of 
 which in succession would then receive the sewage for six hours. In this way the 
 sewage of a. water-closet town of 10,000 inhabitants could, at a very moderate 
 estimate, be cleansed upon five acres of land, if the latter were well drained to the 
 depth of six feet.' 
 
 "The number of persons to an acre proposed in this passage is 
 
2,ooo, but Dr. Frankland afterwards estimated it might be increased to 
 3,000 or even more. 
 
 "The hint given by Dr. Frankland was immediately acted on by 
 one of the most experienced sanitary engineers of the day, Mr. Bailey- 
 Denton. A long and active employment on land drainage works had 
 led him to observe the absorbent and cleansing powers of aerated soils, 
 and the purity of the water issuing from deep underdrains, and he 
 established a system of sewage treatment on the intermittent filtration 
 principle at Merthyr Tydfil. The works were described in a subsequent 
 report of the Rivers Pollution Commissioners ; 20 acres of porous soil 
 drained from s to 7 feet deep were prepared to take the sewage of 16,600 
 inhabitants and the effluent was stated to be satisfactory. 
 
 "These works were complicated by being combined with broad 
 irrigation, but a few years later Mr. Bailey-Denton carried out a more 
 positive example of the new principle at Kendal. Here he allotted a 
 plot of 16 acres of very porous ground to take the sewage of 13,700 
 people, an allowance of about 900 persons to an acre. But the 
 authorities of the town, wishing to try in the first instance the larger 
 proportion, originally recommended by Dr. Frankland, began with 
 only 5 acres, proposing to increase it if necessary. The land was 
 well underdrained to 6 feet deep ; it gave an effluent perfectly colourless 
 and sweet, and it worked for some years fairly well, thus taking 2,740 
 people per acre. 
 
 " But, Mr. Denton protesting against the overtaxing of the soil, the 
 filtering land was afterwards increased to 10 acres. used intermittently, 
 and the other six acres were irrigated with sewage on the ordinary plan. 
 This, taking the whole, gives about 850 people to the acre, instead of 
 100 as allowed for broad irrigation. The effluent continues good, clear, 
 and colourless. 
 
 " It was natural that a plan differing so materially from the ordinary 
 mode of sewage application to land should be strongly criticised, and 
 that objections should be raised against it. The Rivers Pollution 
 Commissioners, in propounding the plan, suggested some objections 
 that might be made to it, and these have been supplemented by others. 
 
 " They may be briefly stated as follows : — First, that the plan is 
 wasteful, as not fitted for producing crops. Secondly, that the concen- 
 tration of so large an amount of sewage on a small area will produce 
 greater nuisance than other modes of treatment. Thirdly, that the 
 soil receiving such large quantities of sewage will, after a time, become 
 overloaded and clogged, so losing its filtering power. Fourthly, that 
 the cost of preparing the land is so great as to preclude its adoption ; 
 and Fifthly, that the success of the process would be doubtful with 
 ordinary management on a large scale. 
 
 "Mr. Bailey-Denton has given particular attention to these ob- 
 jections, and he has explained in his book of 1880 the result of ten 
 years' experience in regard to them. 
 
 " In the first place, with the view of rendering the process more 
 manageable, he has thought it expedient considerably to reduce the 
 quantity of sewage which the originators of the scheme stated might be 
 put on the land. Instead of allowing upwards of 3,000 people to the 
 acre he limits the number to about t,ooo. 
 
" The first objection is that with such a large supply of sewage it 
 would be impossible to grow crops, and that therefore the process 
 would be unremunerative. This objection has been shown by Mr. 
 Bailey-Denton to be, at least with the reduced quantity, unfounded. 
 At Kendal, for example, out of the lo acres used intermittently for 
 filtration, 4 acres grow cabbages, 2 mangolds, 2^ carrots, and the 
 remainder miscellaneous garden produce. In other places a similar 
 result has been obtained. 
 
 " The second and third objections maybe taken together. It was 
 suggested that the collection of the solid matters of the sewage might 
 give rise to a formidable nuisance, especially in hot weather, and might 
 clog the pores of the land so as to prevent proper filtration. 
 
 " Experience has not warranted these fears ; but at the same time it 
 appears to be advisable previously to separate the solids to some extent. 
 It is certain that the more the liquid approaches clarification the less 
 land will be required, and the less danger will there be of unpleasant 
 odours. For a small number of people, say under 500 to the acre, the 
 sewage may be applied as it comes, leaving the grosser matters to 
 become amalgamated with the soil. But if the number be increased, 
 the previous removal of the sludge would be desirable, and for 1,000 or 
 more it would probably become absolutely necessary. 
 
 "The fourth objection is as to the cost of preparing the land. 
 There is no doubt that the proper laying out of the land is a very 
 important element of success. Mr. Denton says : — 
 
 " ' The preparation and formation of land to receive sewage should be effected with 
 precision, and not in the careless way in which it is sometimes suggested sewage 
 farms may be laid out. There is no economy in carelessly executed land prepara- 
 tions, and it is greatly to be regretted that such views have been inculcated.' 
 
 " It follows, therefore, that the cost of preparing land for this system 
 must be greater than that for broad irrigation ; but when the tenfold 
 efificLency of each acre in doing work is taken into account, this can be 
 well afforded. Mr. Bailey-Denton considers that the cost of preparing 
 the filtration areas in the most difficult cases might amount to nearly 
 ;^i5o per acre, and in others it might be done for ;^3o ; the average he 
 puts at about ^Cio. The actual cost at Abingdon was .^^85. 
 
 "The fifth objection is a doubt whether the process would succeed 
 with ordinary management on a large scale. 
 
 "It is obvious, from the description of the process, that common 
 farming work will not do j the management must be careful and skilful 
 to ensure the proper intermittency of application and regulation of 
 quantity of flow, without which the system must act imperfectly. 
 
 "But whether this requires more than can be reasonably and 
 perfectly done at a moderate expense is a question of experience ; and 
 this, so far as it has gone, appears not to favour the objection. 
 
 " It will be now understood that the essential difference between the 
 intermittent filtration system and that of ordinary broad irrigation is as 
 follows : 
 
 " Broad irrigation means the distribution of sewage over a large 
 surface of ordinary agricultural ground, having in view a maximum 
 growth of vegetation (consistently with due purification) for the amount 
 of sewage supplied. 
 
" Filtration means the concentration of sewage, at short intervals, 
 on an area of specially chosen porous ground, as small as will absorb 
 and cleanse it ; not excluding vegetation, but making the produce of 
 secondary importance. 
 
 " The intermittency of application is a sine quA non even in suitably 
 constftuted soils, wherever complete success is aimed at. No instance 
 of failure, says Mr. Denton, can be pointed out where careful under- 
 drainage and suitable preparation of surface with proper periods of rest 
 have been adopted; whereas the cases are unfortunately becoming 
 numerous in which defective effluents are discharged, and considerable 
 nuisance is created on the surface, when large quantities of sewage are 
 poured on without regulated periodical application. 
 
 "Mr. Bailey-Denton attaches great importance to the judicious 
 combination of intermittent filtration, as a certain means of purifying 
 foul liquid, with surface irrigation as the only means of utilising sewage 
 to the full extent possible, the former serving, so to speak, as a safety- 
 valve for the latter. 
 
 " He has carried out works on this principle at Abingdon, Malvern, 
 Barnsley, and elsewhere, and has given a table in Q. 18,653 of ^ 
 number of places in which the intermittent system has been used, 
 either alone or in combination. 
 
 " In regard to this combination he says : — 
 
 " ' If instead of leaving sewage when applied to land to flow where it will, over 
 irregular surfaces in the varying quantities in which it is usually discharged from 
 towns, proper steps were taken to deliver for surface irrigation only such quantities as 
 are wanted by the cultivator, by taking advantage of the power we always possess of 
 cleansing any quantity of sewage by intermittent filtration through a small area of 
 land, not only would sanitary authorities conform to the requirements of the law in 
 relation to the purification of their sewage with a less charge upon contributing rate- 
 payers than is involved in any other treatment, but agriculture would secure a benefit 
 in its profitable utilization at present withheld.' 
 
 " He also remarks : — • 
 
 " ' That by adopting properly devised intennittent filtration areas which allow of 
 no overflow from the surface into rivers, nor any discharge but from the underdrains 
 (except in times of excessive rainfall, and then only by regulated storm overflows), 
 the constantly recurring evils due to inattention on the part of those who have the 
 care of the disposal works, are completely removed.' 
 
 "The following conclusions, drawn up by so experienced an 
 authority, will throw light on some important points connected with 
 this matter. 
 
 " ' That where agricultural land can be obtained for the purpose at a cost not 
 exceeding 50 per cent, above its ordinary saleable value, resulting in a rent-charge 
 not exceeding £,2 \os. an acre, the sewage should be applied to it on the principle of 
 surface irrigation on a wide scale, combined with intermittent filtration ; and if the 
 extent does not exceed that which will satisfy the demands of local markets for 
 vegetables and grass produced from it, an immediate retijrn may be expected 
 sufficient to pay all outgoings, including the renting charge. 
 
 " ' That where land can only be obtained at a price involving an anijual charge ot 
 ;^I0 an acre and more, a sanitary authority is only justified in acquiring just 
 sufficient land to secure a permanent cleansing of the sewage, which m^y be limited 
 to one acre for every thousand of the population, always assuming that the land is 
 quite suitable, that it is naturally or artificially underdrained to the full depth of six 
 feet, and properly prepared to receive the sewage, and Ihat the sewage is applied 
 quantitatively and intermittently. 
 
 "'In applying sewage to land for irrigation, the wider the area beyond the 
 
quantity that will meet the demands of local markets for sewage produce, the greater 
 will be the loss upon the present ratepayers. 
 
 " ' Sewage farming can never be remunerative to the Sanitary Authority who lets, 
 nor to the farmer who hires the sewaged land, so long as the latter is compelled to 
 take and cleanse the sewage at all times and under all conditions. It is therefore 
 essential that a properly prepared plot of land for intermittent filtration should be held 
 by the Local Authority to receive the sewage when not wanted by the farmer. 
 
 " ' The practice of loading land laid out for irrigation with excessive quantities of 
 sewage should be strictly avoided, as one subversive of the law in respect to river 
 pollution, and opposed to economical results from sewage utilization ; this point will 
 be g.iined by the provision of a properly prepared plot of land for the intermittent 
 filtration of the sewage which is in excess of the quantity actually required. 
 
 " ' Land receiving sewage shouW be most carefully prepared to distribute it 
 while in a fresh condition. All half and half measures result sooner or later in river 
 pollution, and loss to the ratepayers.' 
 
 " We may now compare this process with the former one of broad 
 irrigation in regard to the three questions : Will it produce effectual 
 purification 1 Will the process be in any way objectionable ? What will 
 be its cost i 
 
 "(i) As to the purity of the effluent, the Rivers Pollution Com- 
 missioners said, ' it would be difiScult to decide between filtration and 
 irrigation ;' but there are some reasons why the filtration process would 
 seem to have the advantage. In the first place, the system and motive 
 of working would be totally different, the purification being the principal 
 thing aimed at, and the vegetation only secondary and subsidiary, so 
 that the attention of the management would naturally be directed to the 
 quality of the effluent as the chief aim. 
 
 " Moreover, in filtration ground properly laid out, there ought to be 
 no communication between the influent and the effluent channels except 
 through the pores of the land, so that the sewage, in order to get away, 
 must necessarily pass through the filter. By this means the process of 
 purification becomes not optional (as in broad irrigation), but com- 
 pulsory. And supposing the persons working the farm had at any 
 time an inducement to pass away the sewage unfiltered, they could 
 hardly do so without such a derangement of the works as would attract 
 immediate attention. 
 
 " (2) In regard to the liability to objection, we believe this process 
 has the advantage over broad irrigation. For the liability of nuisance 
 would, if the sludge were previously removed, be reduced by the 
 smaller area of land exposed ; and the danger to subsoil waters would 
 be diminished by complete and skilful underdrainage. 
 
 " (3) The cost of the process is materially affected by the much 
 smaller quantity of land required. 
 
 " It would perhaps, hardly be safe to adopt Dr. Frankland's esti- 
 mate of 3,000 people to the acre, as no such number has been subjected 
 to practical trial, except on the very small experiment at Kendal. The 
 quantity will depend materially on the nature of the land, but as a 
 general estimate it would be safer to take Mr. Bailey-Denton's more 
 moderate estimate of 1,000 to the acre, which is ten times the number 
 usually allotted to broad irrigation. 
 
 "The cost of preparation per acre would, as we have already 
 remarked, be increased, as would also the cost of management, and 
 the returns of produce would be of course much less. 
 
ro 
 
 " Still on the whole, there would, no doubt, be a large saving over 
 the cost of broad irrigation. 
 
 " With regard to filtration through land, we are of opinion — 
 
 " I. That the process has great scientific merit, and offers valuable 
 practical advantages for the disposal of sewage in situations where broad 
 irrigation is impracticable, and where land suitable for filtration can be 
 obtained. 
 
 " 2. That, however, it appears desirable, when the area of land is 
 considerably reduced, that the sewage should be previously treated by 
 some efficient process for removing the sludge. 
 
 " 3. That an arrangement of this kind would be applicable to the 
 metropolis, as we shall explain more fully hereafter." 
 
 Since the publication in 1880 of the first edition of this treatise, 
 the author's firm (Messrs. Bailey-Uenton, Son, and North) have laid out 
 several additional sewage farms on the principle of Intermittent Downward 
 Filtration through natural soil, per se, and in combination with Broad 
 Irrigation, and as it is probable that a description of them would 
 strengthen the conclusions which have been already come to from 
 perusing the statements already given, the author has selected for 
 publication three representative cases to illustrate the progress made. 
 They lengthen the period of experience from ten to fourteen years, 
 and cannot fail to show what may be done by Local Authorities to 
 remove the doubts and difficulties which have resulted from the 
 indecision prevailing with the highest authorities. But before entering 
 upon these details the author has thought it better to explain the present 
 condition of the several farms which formed the subject of the first 
 edition. He will do so in the order in which they originally appeared. 
 
 1. MERTHYR TYDFIL, GLAMORGANSHIRE. 
 
 It will be remembered that in this case the District Authority had 
 committed itself to the purchase of 375 acres of land for Merthyr Tydfil 
 alone, with its population of 50,000, with the intention of utilising that 
 area for Broad Irrigation, but that in consequence of the success that 
 attended the laying out by the author of 20 acres (a part of this land) 
 for Intermittent Filtration, and the discovery therefrom that it was much 
 more economical to adopt Intermittent Filtration per se, or in combina- 
 tion with Broad Irrigation, than Broad Irrigation alone, an arrangement 
 was made to bring into combination with Merthyr Tydfil the districts 
 of Aberdare, Mountain Ash, and Treharris (Quaker's Yard), with a 
 
II 
 
 united population of 100,000. On this combination being made, 
 instead of 375 acres being required for Merthyr and its 50,000 persons 
 alone,- it was found that a less area would suffice for the combined 
 districts with their 100,000 persons. 
 
 On the 14th of June, 1884, Mr. Harpur, the local engineer and 
 surveyor of Merthyr, in reply to an inquiry, obligingly informed the 
 author that the quantity of land sewaged for the combined districts 
 was 336 acres, and that the return obtained from that area over and 
 above the expenditure upon it, and exclusive of rent, was for the year 
 ending 25th of March, 1884, ;^452 9^-. ^d. — not a bad rent. In the 
 same month (June, 1884) the medical officer of the district wrote, saying, 
 " the Troedyrhiew areas do their work thoroughly." 
 
 2. KENDAL, WESTMORELAND. 
 
 This farm, which was originally laid out by the author, and consisted 
 of only 5 acres, having been increased to io|- acres (see original state- 
 ment), with 2 additional acres used for Rye Grass, and 3I acres as 
 ordinary rheadow, still continues to do its work very well, and to the 
 satisfaction of every one connected with it. Mr. Banks, writing on the 
 26th August, 1884, says: " I have now given up being Borough Surveyor 
 here, and have discontinued the management of the farm. A committee 
 have it in hand, I, however, take great interest in it, as I think it one 
 of the most successful schemes for dealing with sewage that there is 
 in the country." 
 
 3. ABINGDON, BERKSHIRE. 
 
 On the 27 th of May, 1884, the local surveyor wrote as follows : — 
 " In reply to your letter of yesterday, I have to state that the Council 
 thoroughly approve of the mode you adopted for the disposal of the 
 sewage. We have not received at any time any complaint as to any 
 local nuisance. The whole of the farm is let for £^ 10s. per acre. 
 The tenant of the farm objected to the solid ingredients of the sewage 
 being removed from the liquid, saying that ' the richer the sewage the 
 better I like it.'" 
 
 4. FORFAR (SCOTLAND). 
 
 The account of this farm is even more satisfactory than that of 
 Abingdon. The manager, writing to the author in the early part of 
 
12 
 
 1 884, stated that there was a balance in favour of the farm for the year 
 1882-3 of ^247 6s. 2^d; adding, "the farm is giving every satisfaction, 
 and the effluent is always quite clear." For the year 1883-4 the 
 following, statement extracted from the Annual Official Statement, 
 shows the revenue and expenditure : — 
 
 Revenue. 
 
 Barley 
 
 Carrots ... 
 
 Hay 
 
 Turnips and mangolds 
 
 Grass 
 
 Sand and Gravel 
 
 Rent of Inchmacoble grass field 
 
 Half-year's rent of Orchardbank House 
 
 Total revenue 
 
 £ s. 
 
 12 6 
 
 15 7 
 
 3 18 
 
 193 12 
 
 189 I 
 
 48 8 
 
 27 o 
 
 IS o 
 
 d. 
 6 
 
 3 
 o 
 
 7 
 
 II 
 
 10 
 
 o 
 
 o 
 
 ^504 IS I 
 
 Expenditure. 
 
 
 
 £ 
 
 s. 
 
 d. 
 
 Horse labour 
 
 ... 
 
 31 
 
 9 
 
 
 
 Manual labour 
 
 ... 
 
 rSS 
 
 9 
 
 10 
 
 Seeds 
 
 
 9 
 
 3 
 
 2 
 
 Auctioneer's commission, &c. 
 
 
 14 
 
 18 
 
 7 
 
 Printing, &c. 
 
 ... 
 
 I 
 
 3 
 
 
 
 Farm implements and repairs 
 
 of tools 
 
 5 
 
 6 
 
 
 
 Painting Orchardbank House 
 
 ( • ■ • • > • • 
 
 3 
 
 5 
 
 5 
 
 Total expenditure ... 
 
 . ^220 
 
 15 
 
 
 
 Revenue 
 
 ••■-^504 15 I 
 
 
 
 
 Expenditure . . . 
 
 220 15 
 
 
 
 
 £284 
 
 " The balance of revenue over expenditure, considered as rent for the 
 farm, which extends to 38 acres, is equal to the sum of ;^7 9^. 6d. per 
 acre. As compared with the previous year, the result shows a net 
 increase of revenue over expenditure of £56 i^s. jo^d. The yield 
 from barley and carrots is less — in the one case by ;£$ 8s. ^d., and in 
 the other by ;£' 1 2 3^. 4d. ; but turnips and mangolds have brought 
 ;^23 IIS. ^d. more than last year, and grass ;^i6 os. iid. No cabbages 
 were grown on the farm this year. The income from this source was 
 ;^i7 IIS. 8d. last year. The sum received as rent from the Inchma- 
 
coble grass field shows an increase of ;!^8, and the proceeds from sand 
 and gravel have been higher by j£i;i i8s. lod. Last year £21° was 
 received as rent from Orchardbank House, but only £is, has been 
 received this year. On the expenditure side a reduction has been 
 effected of ;^8 105, The year's result of the Sewage Farm, as seen 
 from the balance-sheet, must be considered highly satisfactory." 
 
 This account, though extremely satisfactory to the author, is not 
 more so than the report of Mr. Alexander Campbell, inspecting officer 
 to the Board of Supervision, Scotland, who, having visited the farm, 
 publicly advised all Sanitary Authorities to pay it a visit and judge for 
 themselves. He says : " To ensure success it is requisite that the work 
 should be skilfully designed and executed, and afterwards properly 
 superintended. In both these respects the Local Authority of Forfar 
 have acted wisely. The engineering was entrusted to the firm of 
 Messrs. Bailey Denton and Co., who have made it a speciality ; and 
 the services of Mr. Jonas Harris, sent down by the engineers to carry 
 out the work, were permanently secured to superintend it when finished, 
 and to work the farm. ... It will be observed that the farm is 
 charged with 4 per cent, on _;^4,ooo, the purchase money of the 40 
 acres, which makes a very high rent per acre; with 4 per cent, on 
 ;^i,5oo, the expense of the engineering works, and with the ordinary 
 working expenses; and that, after paying all this, a profit remains. 
 Local Authorities with whom the financial question is all important, 
 should consider this well. They will here find a great sanitary benefit 
 obtained, and combined with it a commercial success. Lord Strathmore, 
 in forbidding the further pollution of the loch, has thus conferred a 
 benefit on the inhabitants of Forfar, and riparian proprietors may from 
 this be encouraged to take all necessary steps to secure the purity of our 
 streams and rivers by enforcing the provisions of the Rivers Pollution 
 Act." 
 
 5. GREAT MALVERN. 
 
 In this case Mr. Palmer, the local surveyor, wrote on the 29th 
 of March, 1882, as follows : — "I am glad to say the works are very 
 satisfactory — the areas are performing their work well, and the effluent 
 is all that can be desired. The income (1882) about balances the 
 expenditure." 
 
 In 1884 the District Accounts show that there was a balance in favour 
 of the farm of;^i62 15^. \d., which was carried to the credit of the 
 District Rate. 
 
14 
 
 6. HALSTEAD, ESSEX. 
 
 In this case, where an unsuccessful attempt was made to introduce 
 wind as a motive power for pumping, little is to be said beyond the fact 
 that a good rent has been obtained from the land which is not likely 
 to continue for long, inasmuch as the Board have agreed, the author 
 understands, to plant all the filtration areas with osiers, the roots of 
 which will in time fill the drains. It is needless to say, after the re- 
 marks on Osier Beds, which appear in Chapter IV of this treatise (First 
 Edition), that this proceeding is opposed to the advice of the author. 
 
 The distance of this little farm from the town, and the fact that 
 there exists no buildings upon the land, much reduces the chances of a 
 favourable letting. Nevertheless the whole of the land is now let with 
 the sewage for ;^8o a year, or more than 2 per cent, on the cost of the 
 land and preparation. 
 
 7. BARNSLEY, YORKSHIRE. 
 
 This farm, which it will have been seen in the original edition 
 consists of a loamy " clay," and is therefore not so porous in subsoil and 
 free in action as is desirable, is still satisfactory. 
 
 The manager writes on June sth, 1884 : "The farm is not yet pay- 
 ing its working expenses, but there are now no complaints whatever 
 from adjoining landlords, nor any threats of a renewal of proceedings 
 in the Court of Chancery." 
 
 This, it will be seen, is a case in which the surface waters to a great 
 extent find their way into the sewers and very largely increase the 
 quantity of liquid to be dealt with. This is very unfortunate where the 
 land is of a clayey character. Though the population is now less than 
 30,000, the quantity of liquid sewage often reaches 1,000,000 gallons in 
 24 hours. 
 
 8. HITCHIN, HERTFORDSHIRE. 
 
 The result in this case cannot be more appositely expressed than in 
 the words of the Chairman, who, in May last (1884), stated that " he did 
 not think that any town in the kingdom could show a more satisfactory 
 state of things as regards sewage disposal," followed as that encomium 
 was some months after by the following account given in the proceedings 
 of the Board : — 
 
 " Mr. A. Ransom read a comparative statement, showing the quantity 
 of liquid delivered from the town sewers at various hours of the day in the 
 
15 
 
 year 1883, and at the same season in the present year. The quantities 
 varied from two-thirds to one-half in 1884 to what it was in 1883. 
 Mr. Ransom said the land was fully equal to deal with all that was now 
 delivered to it." The account goes on to state — 
 
 " It is only due to Mr. Denton, who laid out the farm as engineer to 
 the Board, to say that he always contemplated the diversion of extraneous 
 water from the sewaged land ; but this part of his scheme was not fully 
 carried out, the consequence being that, owing to excessively wet seasons, 
 a large amount of subsoil drainage water found its way into the sewer, 
 thus deluging the farm and preventing the land doing its work. This 
 season, however, has been so dry that probably not much beyond the 
 normal quantity of sewage has found its way to the farm, and thus the 
 farm has for the iirst time had a fair chance of proving its efficiency, 
 which, according to the statement of the Committee, it has now done. 
 It is only just to Mr. Denton that this statement should be made.'' 
 
 9. OAKHAM, RUTLAND. 
 
 There is nothing whatever to add to what has already been said as 
 to Oakham and the remaining cases described in the first edition of 
 this treatise ; though it is satisfactory to state that Mr. Finch, of Burley- 
 on-the-Hill, M.P. for the county of Rutland, the owner of the town of 
 Oakham, has himself continued to cleanse the sewage on the same land, 
 and wrote to the author in June last (1884) stating that he was quite 
 satisfied with the result, both as regards the disposal of the sewage and 
 the return obtained. 
 
 The author did not execute the works. They are referred to here 
 because they exemplify what an owner has successfully taken upon 
 himself to do. 
 
 The following are the selected cases that have been dealt with since 
 the date of the first edition (1880) : — 
 
 DEWSBURY, YORKSHIRE. 
 
 This case is of considerable interest owing to the fact that Dewsbury 
 is a manufacturing town of importance on the River Calder, and that 
 " middens " (closets) are chiefly used by the inhabitants. The population 
 is about 30,000. The quantity of trade liquid of no manurial value to 
 be disposed of, either by admission into the sewers and treatment on the 
 land or otherwise, is very considerable, whilst the quantity of solid faecal 
 matter of value as manure is comparatively small. 
 
i6 
 
 The quantity of land prepared for filtration is 50 acres, with rather 
 more than 10 acres for surface irrigation ; the whole area utilised includ- 
 ing banks, roads, &c., being over 70 acres. The land here referred to 
 consists of the greater portion of Mitchel Lathes Farm. The soil, for the 
 most part, is very porous and of a sandy character, very suitable for 
 filtration. The work of preparation has been more than ordinarily 
 expensive owing to the necessity of forming the surface into comparatively 
 few horizontal areas, which involved the removal of a great quantity of 
 earth; yet the cost on the whole has not exceeded ;^i 10 per acre. 
 There has been considerable expense incurred in substituting a new 
 outfall channel for the Chickenly Beck (which before ran through the 
 farm), and in the construction of roads, besides the erection of a wall 
 as a boundary. The principal feature of this farm is its evident capability 
 of serving for the cleansing of much more sewage than is discharged from 
 Dewsbury alone if the surface waters be carefully excluded from the 
 sewers and the trade liquid properly treated. There is no doubt what- 
 ever that if the numerous chemical ingredients used in the trades of 
 Dewsbury were altogether excluded, and solid flocculent refuse properly 
 screened from the liquid before it reaches the land, it would absorb 
 and cleanse nearly any amount of liquid that could be applied to it. 
 At present, however, contrary to the advice of the author, no means 
 have been adopted to separate the solid matters from the liquid sewage, 
 and the consequence is that the furrows by which the sewage is dis- 
 tributed hold matter which is extremely objectionable without being 
 beneficial to vegetation. 
 
 The farm manager on the 25 th of May, 1884, wrote to the author 
 saying : " The sewage farm is doing better this season than before, and 
 the crops are looking very fair, but we cannot expect very heavy crops 
 as the land is very poor, some of it having been cropped four times 
 without having manure of any kind. The sewage consists chiefly of 
 dye wash ; nevertheless the effluent is very good, and every one that sees 
 it is surprised to see how clear it is. There are a great many mill 
 hands come to have a bathe at the outlet, it being the only clear water 
 for miles that they can bathe in." This fact is striking because it was 
 from this part of the River Calder that the Rivers Pollution Commission 
 took the water wherewith to write their " Memorandum " showing the 
 condition of the river. 
 
^7 
 
 WITHINGTON, LANCASHIRE. 
 
 The next case is that of Withington with Levenshulme, which 
 together present a case of some interest owing to the locality being in 
 close proximity to Manchester, our greatest commercial centre, and to 
 the River Mersey, a stream which is befouled by sewage to perhaps a 
 greater extent than any other river in the country. The present popula- 
 tion of Withington and Levenshulme, contributing sewage to the farm, 
 may be taken at 21,000; it has been proposed to add the district of 
 Rusholme with its population of 12,000, which together would raise the 
 present population to 33,000, whilst there exists a prospect of rapid 
 increase from the proximity of the combined districts to large and 
 populous towns. The whole case is one of an instructive character. 
 
 The filtration areas are designedly laid out to purify daily one million 
 gallons of sewage, — which is a very liberal allowance for a future popula- 
 tion of 40,000 persons, — with an arrangement whereby any excess of 
 that quantity in times of heavj' rainfall may be discharged into the River 
 through Osier Beds which it is hoped will secure clarification. There 
 are no manufactories in the district, and middens exist to some extent. 
 The old sewers are leaky and let in subsoil water which renders the 
 sewage now discharged more diluted than ordinarily. 
 
 The land selected for the treatment of the sewage is situated close 
 to the Mersey at the point where the Chorlton Brook joins that river. 
 Before embankment this land was subject to frequent flooding. The 
 soil is an alluvial deposit, partly of a free character, well adapted for 
 filtration, and partly of a loam inclining to clay, which, though porous as 
 clay, is very much less active than the remainder of the farm. The 
 quantity laid out in level areas and osier beds consists of 78 acres 
 separated from the main valley by a cross bank from the existing river 
 bank to that of the brook. The construction of this new bank and the 
 strengthening of the old ones have necessarily formed a considerable 
 item in the expenditure. The whole of the utilised land has been drained 
 about 5 feet deep, at intervals between the drains varying according to 
 the porosity of the soil, and the drained effluent is discharged by a 
 3 feet earthenware culvert passing under the Chorlton Brook into the 
 Ousel Brook below the Stretford (flood water) Weir. 
 
 Of the 78 acres 49 only are laid out for filtration, the remaining 
 29 acres being appropriated to Osier Beds, enbankments, and roads, 
 with some marginal land outside the embankments not utilised at all. 
 
 B 
 
i8 
 
 The total outlay in preparation has been ^i 2,887, but if from this amount 
 there be deducted the outlay on the banks, and the construction of the 
 outfall drain into the Ousel Brook, the cost per acre would not 
 exceed ^118. The outlay, moreover, was very sensibly increased by 
 the difficulties attending the position of the land and the somewhat 
 frequent floods that occurred during the operations. The farm is at 
 present in the hands of the Local Board. It is quite possible that the 
 quantity of sewage has been increased with advantage to the present 
 ratepayers of Withington, inasmuch as all parties contributing additional 
 sewage will be made to pay in relief of those who now are charged with 
 the outlay already incurred, whilst an excellent and an increasing market 
 for the produce of the farm will always be found in the city of Man- 
 chester. Thus the benefits now derived at Merthyr by the extension of 
 the contributing population may be experienced at Withington (see 
 Merthyr). It should be stated that in the design adopted at Withington 
 the system of underdrainage was so laid out as to allow of an increased 
 number of lateral drains, whenever increased capability of absorption 
 may be required, without prejudicial effect. Mr. Joseph Swarbrick, 
 Assoc. M. C. E., the local surveyor, rendered every assistance in carrying 
 out the works. 
 
 WATFORD, HERTFORDSHIRE. 
 
 The last additional instance it is desirable to give represents the 
 drawbacks and advantages which attend a very large class of works 
 where land is resorted to. It is that of the district of Watford, with a 
 population of over 12,000 persons (1884). 
 
 In the beginning of 188 1 the Local Board of Watford was subject 
 to proceedings in Chancery by Mr. Snewing, a neighbour, who sought 
 an injunction to restrain the Board from continuing to pollute the River 
 Colne by allowing the sewage of their district to pass into that river, and 
 the author was called in to advise the Board as to the best means to be 
 adopted to prevent this. The sewage was at that time treated on about 
 1 5 acres of land by ordinary irrigation, whereby the liquid with certain 
 ingredients passed over the surface and found its way into the river only 
 partially cleansed. The 15 acres were made up of 10 acres of rapidly 
 sloping arable ground, and 5 acres of flat meadow land adjoining the 
 river, whilst the soil of which the former was composed was of a very 
 irregular and mixed nature, consisting of beds of clay, gravel, and sand, 
 with the underlying chalk rising up in places to within a few feet of the 
 
19 
 
 surface, whereby any liquid penetrating the overlying earth when it 
 reached the chalk would find its way to the lower depths of that 
 formation. 
 
 It being desired by the Local Board that the area of land utilised 
 should be increased as httle as possible, the low flat land was laid out 
 (undrained) for osiers to receive flood and excess waters, and the lo acres 
 of arable already utilised, together with 4 additional acres of adjacent 
 land, were by the author's advice prepared, drained, and aerated in 
 horizontal terraces to absorb the sewage, so that that which had 
 previously run over would necessarily pass through the soil to the 
 underground channels which were laid to convey it in a purified 
 condition to the river. The area being comparatively small — one 
 acre to each 850 persons — the author, as engineer, made it a pre- 
 cedent condition that all solid matter should be separated from the 
 liquid before it was delivered to the filtration areas, and the Board 
 agreed to do this. He also required, as a sine qud, non, that all foreign 
 water that could possibly be excluded from the sewers should be 
 removed; thus rendering the liquid which had to be cleansed by 
 filtration as free from flocculent matter and as reduced in quantity as 
 possible. 
 
 The preparation of the land was duly executed, and the whole of 
 the sewage of Watford has since been cleansed by passing through 14 
 acres of land, in spite of the fact that the precedent conditions insisted 
 upon have not been fully carried out and yet require fulfilment. 
 Nevertheless the late chairman, Mr. C. F. Humbert, a gentleman of 
 great practical experience in the management of landed property, stated 
 in February last (1884), at one of the last meetings over which he 
 presided, that "when the works came from Mr. Denton's hands they 
 were a decided success," and it is indeed to be regretted that, in an 
 example of such great importance to the people of Watford and to 
 the country at large, pains should not have been most carefully taken 
 by the Local Board to develop Intermittent Filtration in accordance 
 with the principles upon which that method of treatment was founded, 
 and upon which its success depends. 
 
 The existence of chalk underlying the terraces has been made the 
 ground of declaring that the underdrainage was useless (underdrains are 
 as useful for aerating the soil as for discharging liquid), and osiers have 
 actually been planted on the drained terraces, because their cultivation 
 involves less expense than the labour incident to ordinary cropping. 
 
 B 2 
 
20 
 
 (Cultivation of the surface of filtration areas is necessary to ameliorate 
 and comminute the soil for the even absorption of the sewage.) 
 
 At Watford the solid part of the sewage, only partially removed 
 from the liquid, has been thrown out of the tanks upon adjacent ground 
 where it has been left to putrefy and dry, without any attempt being 
 made to render it fit for removal by the process of pressing or otherwise. 
 The collection of this putrescible matter is constantly giving off efHuvium 
 objectionable to the neighbourhood, and as this takes place close to the 
 land utilised for filtration, it has given the farm a character which is in 
 no way due to it ; for it can be proved to demonstration that no smell 
 emanating from the land can be discovered 50 yards from its margin. 
 
 Watford is especially a case to be studied by the sanitary engineer ; 
 the sewage of 12,000 persons has already been delivered to, distributed 
 upon, absorbed by, and filtered through 14 acres of land for many 
 months together, with only the occasional relief which has been afforded 
 in times of excess of rainfall, when the sewage has been removed 
 from the terraces and run through the osier beds, and lower land 
 prepared for the purpose. Watford is, in fact, a case where the existence 
 of a deep porous substratum, serving as an absorbent of the liquid which 
 has passed through the upper crust of soil, may become a source of 
 great evil, if the aeration due to the underdrains be checked, the surface 
 soil not cultivated nor made productive of vegetation, whilst the sewage 
 itself is applied without the required intermittency. 
 
 In publishing the second edition of this treatise, the author desires 
 to express as strongly as he can his conviction — confirmed by his practice 
 since the date of the last edition (1880) — that intermittent filtration, 
 when properly designed and executed, cannot fail in its purpose, if 
 maintained and managed with strict regard to the principles upon 
 which the process is based. At the same time he is compelled to 
 admit that it will assuredly fail, or at any rate will not be satisfactory, 
 when the filtering beds or areas, to save expense, are not prepared with 
 precision, or where the subsequent treatment, in relation to the quantity 
 of sewage applied to a given area, and its intermittency of application, are 
 disregarded. There is no economy, but absolute waste, in rejecting those 
 rules and observations which will ensure the distribution of the sewage 
 evenly over the surface, and through the soil of the beds, in quantities 
 regulated by the character of the subsoil, and the freedom with which 
 liquid will infiltrate. 
 
21 
 
 There is an observation which the author desires to add to the, 
 "conclusions" he previously arrived at and expressed (see page loi) 
 in the first edition of this treatise. It is this : that although he 
 considers that where suitable land of sufficient extent can be obtained 
 it is better and more economical to convey the finer floating ingre- 
 dients (sludge) to the land by the ready carriage of the sewage 
 itself, there is no doubt whatever that, if those floating ingredients 
 be entirely extracted from the liquid by chemical precipitation or 
 mechanical deposition, the liquid so clarified will pass through the 
 same soil— relieved as it will be of all coating matter — with very 
 much greater rapidity. It is true that " sludge " is always acceptable 
 to the sewage farmer, by reason of the manurial qualities it possesses, 
 and that the mineral ingredients (road detritus, &c.), which sludge 
 invariably contains, are valuable for improving the texture of the land 
 for filtration ; but it is equally true that clarified sewage will pass 
 through suitably constituted soil, thoroughly aerated, without any 
 impediment other than that due to the closeness of its interstitial 
 spaces, and that to secure purity the finer those aerated spaces are the 
 more certain will be the result. Reduced to figures it may be taken 
 that the same land will filter double the quantity of clarified sewage 
 liquid that it would cleanse sewage of which the finer particles have 
 not been removed. 
 
 Applying these observations to the great object to which the Royal 
 Commission on Metropolitan Sewage Discharge devoted its attention, 
 _ — the purification of the Thames, — it may be assumed without doubt, 
 that the clarified sewage of 2,000 persons may be purified on each acre of 
 suitable land to which it may be applied ; or, in other words, that if a 
 future population of 7I millions has to be provided for, it only requires 
 3,750 acres, or say 6 square miles, of suitable land to satisfy the 
 requirement. If less than 2,000 persons to an acre be taken as the 
 basis, the quantity of land will, of course, be proportionately increased. 
 
 It is further the wish of the author to express his belief that there 
 exists in the rising ground on the Essex side of the Thames Meadows, 
 between Barking and Tilbury, ample area for purifying the clarified 
 sewage of the whole of the metropolis, without causing any real nuisance 
 of any kind. 
 
 To avoid sentimental — in contradistinction to sound — objections, 
 which might be raised to Sewage Farms in the present instance, it 
 would only be necessary to purchase, under the Lands Clauses Con- 
 
22 
 
 solidation Act, a marginal breadth of clearance land, outside the 
 sewaged area, to which no sewage would be applied. 
 
 That the land pointed out is suitable for the purpose of intermittent 
 filtration has been already signally proved by what has been done in the 
 way of disposing of sewage at the Lodge Farm near Barking, where 
 London sewage was applied, and at Breton's Farm, where Colonel 
 Hope utilised the sewage of Romford. Both these farms are situated 
 on the rising ground that has been pointed out as suitable for the 
 cleansing of the Sewage of the metropolis. 
 
 In the case of the Lodge Farm, Mr. Morgan has stated in his 
 published reports that such was the porosity of some portions of the 
 farm that 451 tons of sewage had to be expended in the production of 
 one ton of grass, and that he had applied in twelve months as much 
 as 21,488 tons per acre, which is equivalent (at 20 gallons per head) 
 to the sewage of a population of 660 to the acre. At Breton's Farm 
 Colonel Hope so arranged the application of the Romford sewage to 
 the land, which was thoroughly drained, that the effluent water was 
 returned to the tanks to be re-applied with the daily outflow of sewage 
 from the town. 
 
 In both these cases the figures represent the quantity of sewage 
 absorbed where the immediate object of the application was not the 
 cleansing of sewage by filtration, but the production of vegetation by 
 irrigation ; and it may be regretted that such facts as these, which show 
 so distinctly the remarkably absorbent powers of the soil, were not 
 elicited by the Royal Commission, for they would go far to satisfy the 
 most sceptical that the land pointed out is capable of purifying the 
 sewage of the metropolis, and at the same time of securing an 
 appreciable return in the shape of vegetable production. 
 
INTRODUCTION TO FIRST EDITION. 
 
 The following treatise, explanatory of what has been done by the author 
 in the way of cleansing sewage by filtration through natural soil, is 
 intended to satisfy sanitary authorities that wherever land is to be 
 obtained, in a greater or less quantity, they have it in their power to 
 prevent the pollution of rivers, at a comparatively moderate outlay, 
 and that they may do so with advantage to the country generally by 
 increasing our food production. 
 
 At the same time he desires to impress his readers with the fact 
 that he recognises in the dissimilar conditions affecting some towns 
 and districts ample reason for difference in the treatment of the sewage 
 discharged from them, and for a varying degree of purification of the 
 effluent. 
 
 With that view he ventures to reprint here from his lectures on 
 "Sanitary Engineering," given before the School of Military Engineer- 
 ing at Chatham (1876), the following passages on the classification of 
 towns and villages according to the nature of their outfalls : — . 
 
 " All towns in this country may be placed in one of these classes, viz. : 
 (i) towns on the sea-board, (2) towns on estuaries and tidal rivers, and 
 (3) towns on inland rivers and tributary streams. I will deal with them 
 under these heads, and add a few special remarks upon the disposal 
 of sewage from villages and hamlets. 
 
 "(i.) Sea-board Towns. — In the economy of discharging sewage 
 directly into the sea, in the case of towns situated on the sea-board, a 
 good and sufficient reason exists for the adoption of that means of 
 disposal wherever it can be done without injuriously affecting the shore. 
 The probability is, however, that the floating matters will return^ and that 
 the soluble matter will mix with the sea so as to pollute the shores, and 
 in sea-bathing towns such a result should not be possible. The possi-. 
 
24 
 
 bility of discharging sewage into the sea unobjectionably only exists 
 where the shore is not used for bathing or for recreation, and where 
 the town does not extend down to the water's edge. Where it stands 
 well above the sea level, and the outfall sewer may be carried far into 
 the sea without converting such sewer into a sewage-reservoir, the arrange- 
 ment may be effected advantageously. 
 
 " In cases where the sewage is impounded within the outfall sewer 
 for a period of time during each tide, not only is the sea-shore too 
 frequently affected in a manner to prejudice the interests of a sea-bathing 
 town, but the inhabitants are injuriously affected by the generation and 
 evolution of gases from the impounded sewage which find their way by 
 the communicating sewers into the houses, and by the gullies and 
 gratings into the streets during the time the sewer mouth is closed. 
 Brighton may be taken as an illustration of this state of things. 
 
 "While the average death-rate of healthy districts is 17 per 1,000, 
 that of Brighton frequently rises above 20, and this excess is only to be 
 explained by the character of its sewerage, the detention of the sewage 
 in the outfall sewer, the mode of disposal, and the overcrowding of 
 dwellings ; for the town possesses all , the advantages due to a 
 southern aspect, an open sea, and a wide reach of downs to shelter 
 it from cold wind whilst affording to the inhabitants the means of 
 healthful exercise. 
 
 " It will have been anticipated from these remarks that, even in 
 sea-board towns, the sewage, before it is discharged, should not only be 
 clarified, but that everything should be done within reasonable limits to 
 secure a constant outflow independently of the tide 
 
 " One or other of the tried chemical precipitation processes will 
 effect the required clarification of the sewage of this class of towns 
 where land cannot be obtained. 
 
 "(2.) Towns discharging into Tidal Rivers and Estuaries. — A con- 
 siderable number of towns in this country are situated on the shores 
 of tidal waters, some of which reach far inland. The difficulty of satis- 
 factorily dealing with sewage which can only be carried to the sea by 
 the ebb of the tide, is very considerable. 
 
 "The banks or shores of these waters generally consist of mud, and 
 are exposed to the atmosphere for a sufficient time during each tide 
 to give off in extremely hot w^eather an intolerable stench, which is 
 necessarily made worse by mixture with sewage. In dealing with 
 towns on tidal rivers it becomes the duty of the engineer to treat the 
 
25 
 
 liquid refuse differently from the way in which he would dispose of the 
 sewage of either a town situated directly on the sea-board, or on an 
 inland river. 
 
 "The most rational view of the matter is that, while the sewage 
 discharged from sea-board towns directly into the sea may be simply 
 clarified : that which is discharged into tidal rivers, the waters of which 
 are not potable should be cleansed of its putrescible matters up to a certain 
 standard, which, though less stringent than that applied to inland rivers, 
 should be sufficiently high to prevent nuisance. 
 
 " The standards recognised by the Conservators of the River 
 Thames, as applicable to districts below the intakes of the London 
 Water Companies, may be adopted for this class of towns. They say 
 of the defaecated water to be discharged from these districts — 
 " ' I. It should be free from an offensive odour. 
 " ' 2. It should be free from suspended matters, or, in other words, 
 be perfectly clear. 
 
 " ' 3. It should not be alkaline to turmeric-paper, nor acid to litmus 
 paper. 
 
 " ' 4. It should not contain per gallon more than 60 grains of solid 
 matter dried at 260 deg. Fahr. 
 
 " ' 5. It should not contain more than three-quarters of a grain of 
 organic and ammoniacal nitrogen pet- gallon. 
 
 " ' 6. It should not contain more than two grains of organic carbon 
 per gallon. 
 
 " ' 7. It should contain not less than one cubic inch of free oxygen 
 in a gallon." 
 
 " It should be observed, however, that one of the eminent chemists 
 who signed this recommended standard. Dr. Frankland, — himself a 
 member of the Rivers Pollution Commission, — added these words : 
 ' The conditions under which fluid which has been contaminated with 
 sewage may be admitted into the Thames, as prescribed in the fore- 
 going report, will, I have every reason to believe, preserve the river from 
 being offensive to the inhabitants upon its banks ; but, whilst thus far 
 agreeing with my colleagues, I wish it to be distinctly understood that, 
 in my opinion, such fluid can only be safely admissible into the Thames 
 on condition that the water is not afterwards used for domestic 
 purposes.' 
 
 "These standards — which, as the Government do not recognise 
 them, are only now useful as indicating the very reasonable view taken 
 
26 
 
 by the Thames Conservancy Board— can, it is declared, be reached by 
 several of the chemical processes now in existence. In the case of tidal 
 rivers which reach far into the country, and the banks of which are 
 exposed at every tide and give off effluvia of increased offensiveness 
 when the tidal water is mixed with sewage, however, it is not only 
 desirable in many instances to separate the solid matters and clarify the 
 liquid as chemical precipitation will suffice to do, but to purify it also. 
 
 " How far the Rivers Pollution Prevention Act may affect towns on 
 tidal rivers remains yet to be seen. In Part II, section 3, it is laid down 
 that ' every person who causes to fall or flow, or knowingly permits to 
 fall or flow, or to be carried into any stream any solid or liquid sewage 
 matter shall (subject as in this Act mentioned) be deemed to have com- 
 mitted an offence against this Act. Where any sewage matter falls or 
 flows, or is carried into any stream along a channel used, constructed, or 
 in process of construction at the date of the passing of this Act, for the 
 purpose of conveying such sewage matter, the person causing, or knowingly 
 permitting the sewage matter, so to fall or flow, or to be carried, shall not 
 be deemed to have committed an offence against this Act if he shows 
 to the satisfaction of the Court having cognisance of the case that 
 he is using the best practicable and available means to render harm- 
 less the sewage matter so falling or flowing, or carried into the stream.' 
 In Part IV of the same Act it is stated that '■^'■Stream" includes the 
 sea to such extent and tidal waters to such point as may, after local 
 inquiry, and on sanitary grounds, be determined by the Local Govern- 
 ment Board, by order published in the London Gazette. Save, as afore- 
 said ' (the exceptions are the Lea and Thames, which are under special 
 control, and the sea or tidal waters the use of which for the discharge of 
 sewage has been sanctioned by Act of Parliament), ' it includes rivers, 
 streams, canals, lakes, and watercourses, other than watercourses at the 
 passing of this Act, mainly used as sewers and emptying directly into 
 the sea, or tidal waters which have not been determined to be streams 
 within the meaning of this Act by such order as aforesaid.' 
 
 " (3.) Inland Towns.— It is not only reasonable but positively neces- 
 sary that considerations altogether different from those ruling in the 
 case of sea-board towns should determine the mode of disposing of the 
 sewage of inland towns. The effluent water in such cases should indeed be 
 freed of all foul or noxious matter (PubUc Health Act, 1875, clause 
 17),- without compromise, and the law should be exercised without 
 hesitation. 
 
27' 
 
 " The influence of the opposition of manufacturers has resulted in a 
 temporary respite, and some ground has been lost by temporising which 
 had been previously gained by slow and certain steps ; but when saying 
 this it is impossible to evade the conclusion that the perfect and 
 permanent cleansing of sewage will be sooner or later insisted upon 
 by every voice in the country, and by no persons more decidedly than 
 by the manufacturers themselves. The standards suggested by the 
 Rivers Pollution Commissioners, at first adopted, then abandoned, by the 
 Government of the day, but which, nevertheless, aftbrd a very good 
 indication of what may satisfy future requirements, precluded the 
 admission of the following liquids into any stream. 
 
 "(a.) Any liquid containing in suspension more than three parts by 
 weight of dry mineral matter, or one part by weight of dry organic 
 matter in 100,000 parts by weight of the liquid. 
 
 " (6.) Any liquid containing in solution more than two parts by 
 weight of organic carbon, or '3 part bj' 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 in a white porcelain or 
 earthenware vessel. 
 
 "(d.) Any liquid which contains a solution, in 100,000 parts by 
 weight, more than two parts by weight of any metal except calcium, 
 magnesium, potassium, and sodium. 
 
 "(«.) Any liquid which, in 100,000 parts by weight, contains, 
 whether in solution or suspension, in chemical combination or other- 
 wise, more than '05 part by weight of metallic arsenic. 
 
 " (/.) Any liquid which, after acidification with sulphuric acid, 
 contains, in ico,ooo parts by weight, more than one part by weight of 
 free chlorine. 
 
 " (g.) Any liquid which contains, in 100,000 parts by weight, more 
 than one part by weight of sulphur, in the condition either of sulphuretted 
 hydrogen or of a soluble sulphuret. 
 
 " (A.) Any liquid possessing an acidity greater than that which is 
 produced by adding two parts by weight of real muriatic acid to 1,000 
 parts by weight of distilled water. 
 
 " (/.) Any liquid possessing an alkalinity greater than that produced 
 by adding one part by weight of dry caustic soda to 1,000 parts by 
 weight of distilled water. 
 
 " Where these standards have been reached for a continuance by any 
 
28 
 
 single treatment of sewage it has been efifected by recourse to land, either 
 by way of wide surface irrigation, or intermittent downward filtration. 
 When local circumstances forbid the acquisition of a sufficient area 
 of land for either of these objects, then one of the chemical processes 
 in association with intermittent downward filtration will have the 
 desired effect. By this latter combination a very small area of natural 
 soil, when properly prepared, will perfect that purification which 
 chemical treatment has failed to reach by itself. 
 
 " It is much to be regretted that chemists do not base their analyses 
 of water sewage on one fixed quantity of liquid. While some give the 
 proportions in parts per 100,000, and in grains per gallon of 70,000 
 grains, other chemists give certain ingredients in parts per million." 
 
TEN YEARS' EXPERIENCE 
 
 INTERMITTENT FILTRATION. 
 
 Public discussion has been recently renewed on that irrepressible 
 subject, the disposal of sewage, which, though frequently described as 
 nasty and offensive, still retains its position as one of the most 
 important problems in the social economy of all countries. That this 
 is the case in England has been most abundantly proved by the facts 
 that the inquiry made in the early part of the present year (1880), into 
 the sewage disposal of the Lower Thames Valley Sewerage District lasted 
 for a period of 45 days, and that no decision acceptable to the Joint 
 Board has yet been arrived at. (December, 1880.) 
 
 My motive for publishing the experiences I have gained in Inter- 
 mittent Filtration, separately and in combination with surface irrigation 
 in the last ten years, arises from no desire to discuss the proceedings of 
 the Lower Thames Valley Main Sewerage Board, but from the conviction 
 that much misapprehension as to the efficacy of land as a purifier of 
 sewage has resulted from the ex-parte statements made and the objections 
 expressed at that inquiry, which, though only bearing on the special site 
 unfortunately selected by the Joint Board at East Moulsey, on the Surrey 
 side of the Thames, have been construed by some persons as applicable 
 to the use of land generally. While abstaining from any remarks on 
 the Lower Thames Valley sewage disposal scheme, the fact that other 
 \a.nd at ITarmondsworth on the Middlesex side of the river was selected 
 by three differeni Engineers — two of whom received premiums of 200 
 guineas each* — will justify my drawing attention to the circumstance 
 that no land within the Thames Valley, other than that of East Moulsey, 
 
 * Mr. James Mansergh and Messrsi. Bailey Denton & Co. 
 
30 
 
 was made the subject of investigation, although 300 acres of the land 
 selected at Harmondsworth — the level of which was forty feet higher 
 than that of the Moulsey land, and therefore free from those physical 
 drawbacks with respect to drainage which was made a special ground 
 of opposition — were sold by public auction by Messrs. Baker and Son in 
 the early part of last year (1879) for ;^2o,ooo — not ^^70 per acre — a 
 price which if it had been taken into consideration would have shown 
 incontestably that land was to have been obtained on the Middlesex 
 side at a moderate cost, free from those residential considerations which 
 increased so largely the value of and the objections to the selected land 
 on the Surrey side. 
 
 ^Vith a view to remove as effectually as possible any false impres- 
 sions that may in consequence prevail, and which may prejudice the 
 interests of Agriculture, I propose to describe in precise terms certain 
 executed works in which Intermittent Filtration is the principal 
 feature, for the accuracy of the details of which I can personally 
 vouch, hoping to prove to the satisfaction of those who may prefer facts 
 to opinions that the particular objections dwelt upon at Kingston, and 
 so often reiterated by Counsel and witnesses at inquiries of the same 
 character — and which must necessarily have some influence on the 
 public mind — are not based on reliable data. 
 The practice In speaking of " Intermittent Filtration," I do not refer to the 
 
 downward ^° practice of crowding sewage continuously on porous land in the 
 filtration careless manner often adopted to get rid of sewage, and which 
 
 results in its collection in hollows and low places to injure growing 
 crops — to depreciate the effluent, if there be any — and to cause a 
 nuisance on the surface of the land — (a proceeding which may deserve 
 the term of "intensive irrigation,'' contemptuously given to intermittent 
 filtration by its detractors,) but I refer to the concentration of sewage at 
 regulated intervals on as few acres of land as will absorb and cleanse it 
 without preventing the production of vegetation. It is by this means that 
 the assimilative powers of growing plants are brought to bear on the 
 fertilising elements of the sewage at the same time that the percolation of 
 the sewage through the soil brings it in contact with the atmospheric 
 air prevading the soil, and renders it harmless liy oxidation, as 
 explained by the Rivers Pollution Commissioners.* 
 
 * In contradistinction to intermittent downward filtration, "surface irrigation" 
 means the distribution of sewage over as many acres as it will wet without super- 
 saturation, having in view a maximum plant growth. To run constantly sewage on to 
 
31 
 
 The particular objections I refer to as those so often repeated by Objections of 
 
 opponents to 
 opponents are : — the process. 
 
 First. That soils become after a time so overloaded with sewage 
 when subjected to intermittent filtration, that their powers of absorption 
 and percolation cease. 
 
 Second. That the concentration of sewage for filtration on a small 
 area is attended with greater nuisance than other modes of treatment : 
 and — 
 
 Third. That the cost of preparing land for intermittent filtration is 
 so great as to preclude its adoption; — this objection being generally 
 based on the erroneous figures given in the report of Messrs. Rawlinson 
 and Read, the Committee appointed by Mr. Sclater-Booth to inquire 
 into the different modes of treating town sewage. 
 
 In the interest both of sanitary science and agricultural progress, it 
 is greatly to be regretted that these objections are so pertinaciously 
 repeated without any real effort being made to arrive at facts. The 
 omission to do so is due perhaps in some measure to the circumstance 
 that the Rivers Pollution Commissioners themselves, when they published 
 the interesting results of the laboratory experiments of Dr. Frankland 
 in 1870, hesitated to recommend the adoption of the process. After 
 declaring that they deduced from the experiments, that "an acre of 
 suitably constituted soil, well and deeply drained, with its surface 
 levelled, and divided into four equal plots, each of which in succession 
 would receive the sewage of six hours, would cleanse the sewage of 
 3,300 persons," they explained that — 
 
 Such a filter was not a mere mechanical contrivance — it was a The theory 
 machine for oxidising and thus altogether transforming, as well as for of intermittent 
 merely separating the filth of dirty water. A field of porous soil irri- ^°wnward 
 gated intermittently, virtually performs an act of respiration, copying on "^^''°"' 
 an enormous scale the lung action of a breathing animal, for it is alter- 
 nately receiving and expiring air, and thus dealing as an oxidising agent 
 with the filthy fluid which is trickling through it. To this chemical 
 property must be added another cleansing agency, the actual appetite 
 for certain dissolved impurities in filthy water which soil owes both to 
 general surface attraction, and to the chemical affinities which some of 
 the ingredients possess. 
 
 A sufficient extent and depth of porous soil having periodical in- Reason of 
 tervals (jf rest during which the soil drains itself and becomes refilled *^ ^\™' 
 with air, certainly must be the best possible strainer, oxidiser, and ^°^'"''?'J 
 filterer of water, containing nauseous organic impurities both suspended sioners for 
 
 gravel or chalk beds, to be soaked in and disappear, as may be seen not far from 
 the Metropolis, is an illustration of " Intensive Irrigation " in its worst shape. 
 
32 
 
 hesitating to 
 recommend 
 the adoption 
 of the process. 
 
 How the 
 anticipations 
 of the Com- 
 missioners 
 were met and 
 removed at 
 iVIerthyr 
 Tydfil. 
 
 and dissolved, — but the adoption of intermittent filtration through land 
 they declared would be open to three formidable objections, viz. : 
 "(i) That it was entirely unremunerative ; (z) That the whole of the 
 manure ingredients of the sewage would be absolutely wasted ; and 
 (3) That the collection of solid faecal matters on 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." 
 
 It may be remembered by those who have traced the progress of 
 Sewage Disposal, that I had it in my power in the very first work of 
 Intermittent Filtration that was executed in this country — z>.,at Merthyr 
 Tydfil in 1871 — to prove that these expectations of the Commissioners 
 were groundless if the operations were modified by the lessons learnt 
 in land-underdrainage. Though my long connection with underdrainage 
 gave me the fullest confidence in the soundness of Dr. Frankland's 
 views, I determined at Merthyr, in the face of the competing processes 
 which were then before the public, to avoid all chance of overcharging 
 the land, and instead of looking to one acre of suitable soil drained 6 
 feet deep to cleanse the sewage of 3,300 persons, as the Rivers Pollution 
 Commissioners had suggested, to extend the area designed to do this 
 duty to three acres by only applying the sewage of 1,100 persons to an 
 acre, and instead of covering the whole surface of the land so utilised with 
 sewage, which would negative the power of crop production, I determined 
 to distribute it by furrows, so as the liquid sewage should reach the 
 roots of the plants growing on the ridges laterally, through the soil 
 without touching their edible parts. 
 
 The result at Merthyr was (and subsequently has been at all other 
 places), that heavier crops of vegetables, giving a better money return, 
 have been grown upon the Intermittent Filtration areas, when cleansing 
 the sewage of 1,100 persons to the acre, than upon surface irrigated 
 land receiving and cleansing the sewage of one-tenth of that population. 
 At Merthyr too (as at other places), the sewage applied being evenly dis- 
 tributed by horizontal furrows, without allowing it to touch the growing 
 crops, has caused no nuisance whatever, nor has any effluvium been 
 recognisable at a distance of 50 yards from the areas. 
 
 Thus the three objections anticipated by the Rivers Pollution Com- 
 missioners were completely removed. The treatment adopted, instead 
 of being entirely unremunerative, secured in every case large crops of 
 vegetables. No collection of solid fgecal matter took place upon the 
 surface of the ground. The sewage being distributed by furrows of 
 different depths so regulated as to feed the so'l with the liquid and 
 
keep back the solid matter in the furrows where it would afterwards 
 be of special value for mixture with the soil, no waste occurs. 
 
 I have quoted the very interesting description given by the Rivers Intermittency 
 Pollution CoQimissioners of the principles or theory upon which Inter- ^d'jS'ensaMe' 
 mittent Downward Filtration was based before describing the several 
 illustrations of the practice itself which I am about to give, because it is 
 desirable that it should be previously understood that intermittency of 
 application is a sine qua non even in " suitably constituted soils," where- 
 ever complete success is aimed at. No instance of failure can be 
 pointed out where careful underdrainage and careful preparation of 
 surface with proper periods of rest (regulated by the character of the 
 soil), have been adopted, whereas the cases are unfortunately becoming 
 numerous in which defective effluents are discharged from the under- 
 drains, and considerable nuisance created on the surface of the sewaged 
 ground where "intensified irrigation" without regulated periodical 
 application has taken the place of Intermittent Filtration in the 
 true meaning of the term, as explained by the Rivers Pollution 
 Commissioners. 
 
 It is equally desirable to remove from the minds of those who take Area of land 
 
 . . required in 
 
 mterest m the subject, any impressions that may exist in consequence different 
 
 of adverse criticism that when I considered it advisable in the first <les<:riptions o 
 
 soil. 
 
 work of the kind (Merthyr Tydfil), to increase the area of land utilised 
 in the proportion of three acres to one acre, there was any intention 
 to discredit the conclusions come to by the Rivers Pollution Com- 
 missioners, as to the cleansing capability of " suitably constituted soil." 
 I aimed at such a modification as would certainly ensure success. 
 In every case the extent of surface must necessarily depend (i) on 
 the capability of the upper soil to absorb, and of the subsoil to 
 infiltrate the liquid applied to the surface; and (2) on the depth to 
 which the land may be thoroughly drained in order to provide the 
 necessary bulk of filtering material, and it was not only to remove all 
 doubts on these points but to overcome the disturbing influences due 
 to mixed soils of nominally the same character and the difiSculties 
 imposed by nature in keeping down subsoil water, that led me to 
 recommend the increased area. 
 
 No arbitrary law applicable to all soils was intended to be laid down 
 at Merthyr. Every day's experience since the execution of that work 
 has served to prove that with the most suitable free soils it is hardly 
 possible to overcharge them with liquid, or to overtax their cleansing 
 
 c 
 
34 
 
 powers, whereas, in the less suitable clayey and peaty soils, the limit of 
 absorptive power is reached before one-fourth of the liquid that would be 
 absorbed by gravelly and sandy land is applied. If we avoid the denser 
 clays as altogether unsuitable (unless they are so altered in their condi- 
 tion by mixing, burning, &c., as to lose their natural character) and 
 regulate the application of the sewage to other soils within the limits of 
 i,ooo persons to the acre of those most suitably constituted, and 250 
 persons to the acre to those least suitably constituted, all other descrip- 
 tions of cultivatable land may be made capable of filtration ; and the 
 advantage of being able permanently to cleanse the sewage of a district 
 where any land more or less suitable is to be purchased or leased in 
 sufficient quantity to meet these limits, cannot be over-estimated. 
 
 When giving the details of the works I am about to describe, I trust 
 I shall be able not only to remove the oft-repeated objections set forth, 
 but to prove that the capability afforded by intermittent filtration, 
 when adopted separately, of minimising the quantity of land required, will 
 ensure the purification of sewage at the least cost to the ratepayer; 
 and when systematically adopted in combination with surface irrigation, 
 may be inade the means of removing the greatest drawbacks experienced 
 by the sewage farmer, and thus afford a tangible benefit to agriculture. 
 Up to this time Agriculture, which it was stated by the highest authori- 
 ties in Europe, would be immensely advantaged by the use of sewage 
 on land, has realised no gain whatever beyond the benefit of learning 
 what to avoid, and what may be looked forward to when the draw- 
 backs incident to novelty give place to facilities which practice will 
 supply. 
 
 Before entering upon these descriptions it may be desirable to 
 explain certain points which have a governing influence in the disposal 
 of sewage when land is resorted t6. They may be considered under the 
 following heads : — 
 
 I. Character, amount, and value of sewage constituting the 
 outflow of different districts. 
 II. The quantity and use of solid matters floating in the sewage 
 discharged. 
 
 III. The temperature of sewage. 
 
 IV. Storm overflows and osier beds. 
 
 V. The character of land, more or less suitable. 
 
03 
 
 I. CHARACTER, AMOUNT, AND VALUE OF SEWAGE. 
 
 The Rivers Pollution Commissioners showed with remarkable 
 clearness in their report of the i6th February, 1870, that the sewage 
 discharged from towns in which no special trades exist was the same in 
 its distinguishing qualities, and this similarity has been found to exist 
 whether the excrementitious refuse of dwellings be admitted into sewers 
 or whether it be collected separately and removed by the scavenger. 
 
 The Commissioners, after giving by numerous analyses the precise character of 
 constituents of the sewage of water-closet towns and midden towns, sewage of 
 
 ° ' waler-closet 
 
 I stated that these analytical numbers show a remarkable similarity of towns, and 
 
 . . _,, . ^ ., , . ... midden towns. 
 
 composition. The proportion of putrescible organic matter in solution 
 in midden towns is but slightly less than in water-closet towns, whilst 
 the organic matter in suspension is somewhat greater in the former than 
 in the latter. They add — 
 
 "For agricultural purposes 10 tons of average water-closet sewage 
 may in round numbers be taken to be equal to 1 2 tons of average privy 
 sewage. The average quantity of chlorine in 100,000 parts of water- 
 closet sewage is ro'66, while in midden sewage it is 11 "54. This 
 difference is very significant ; it shows that, assuming (which is probably 
 approximately the case) all the urine to reach the sewers in both classes 
 of towns, a larger number of individuals contribute to a given volume 
 of sewage in midden than in water-closet towns. Chlorine, in these 
 cases, represents common salt, and the latter again indicates the pro^ 
 portion of urine in the sewage. The proportion of chlorine, therefore, 
 ought to give the proportion of average individuals (men, women and 
 children) contributing to each kind of sewage ; and from this it would 
 follow that the population producing equal volumes of sewage in midden 
 and water-closet towns are as follows : — 
 
 In water-closet towns ... ... 1,066 
 
 In midden towns ... ... ... 1,154 
 
 " The cause of this difference in the volume of sewage per head of 
 population in the two classes of towns is obviously to be sought for in 
 the somewhat increased quantity of water needed by and supplied in the 
 former." 
 
 The liquid refuse from manufacturing works, however, may alter the As to 
 character and value of sewage, if admitted into sewers, to a great extent, trad^li^'^d' 
 It is therefore essential in designing works for the utilization of sewage refuse, 
 on land that the details given by the Rivers Pollution Commissioners of 
 the refuse liquid discharged from trades of different character should be 
 
 c 2 
 
River? Pol- 
 lution Preven- 
 tion Act, 
 1876, Section 
 7, to be con- 
 sidered. 
 
 As to 
 
 quantity of 
 trade liquid. 
 
 Of subsoil 
 water ad- 
 mitted into 
 
 Sewage 
 proper. 
 
 carefully considered, and that the facts with respect to the trades existing 
 in districts under treatment should be ascertained with precision. 
 
 By the wording of the 7th section of the "Rivers Pollution Prevention 
 Act, 1876," it will be seen that the Legislature contemplated the admission 
 of trade liquids into sewers as far as possible, for it is declared that — 
 
 " Every Sanitary or other Local Authority having sewers under their 
 control shall give facilities for enabling manufacturers within their 
 district to carry the liquid proceeding from their factories or manu- 
 facturing processes into such sewers, provided that this section shall not 
 extend to compel any Sanitary or other Local Authority to admit into 
 their sewers any liquid which would prejudicially affect such sewers or 
 the disposal by sale, application to land, or otherwise of the sewage 
 matter conveyed along such sewers, or which would from its temperature 
 or otherwise be injurious in a sanitary point of view." 
 
 It is therefore some satisfaction to know from the experience already 
 gained that the ingredients used in trade when dissolved and mixed with 
 sewage do not always injuriously affect vegetation. Some are found to 
 be harmless and others beneficial. The quantity of water used in some 
 trades, however, is so great as to be alone prohibitory to its admission 
 into sewers, for instances are not rare in which as much water is used in 
 a single mill as that consumed in a moderately sized town. 
 
 The quantity of sewage forming the constant discharge from the 
 sewers of any district depends very greatly upon the amount of dilution 
 to which the " sewage proper " is subject by mixture with subsoil water, 
 and the amount necessarily affects in the highest degree the mode of 
 sewage-proper disposal. The "sewage proper" of a district consists 
 simply of the water supply made filthy by use when passing through 
 habitations. It frequently happens that this is more than doubled by the 
 water finding its way into the sewers from the ground in which they are laid. 
 One of the greatest difficulties, in fact, with which an engineer has to 
 contend is the existence of subsoil water, inasmuch as any joints which are 
 not water-tight not only admit the subsoil water into the sewers to dilute the 
 sewage, but they allow the sewage which should be confined to the sewer 
 to escape under pressure into the surrounding soil through the same 
 interstices that would admit the subsoil water. Sewers should therefore 
 be invariably made watertight, and where underground water stands 
 sufficiently near the surface to cause injury to the health of the locality 
 it should be lowered by independent subsoil drains. All sewers jointed 
 with clay are particularly subject to much variation of outflow. Nothing 
 in truth has led more directly to unsatisfactory results than the use of 
 
37 
 
 clay for jointing under the pretence of economy, for in wet soils the 
 sewage-proper has from such causes been doubled and trebled in 
 quantity, while under other influences the discharge from the sewers 
 has been so much reduced as entirely to defeat good management. 
 
 It is now generally conceded by sanitary engineers that surface Of surface 
 waters should be excluded as far as practicable from public sewers, and "^^^"^ f^^^ 
 that a separate system of surface-water drains should exist in all towns to sewers, 
 take the rainfall to the natural streams of the watershed. Objection has 
 been raised, however, to the exclusion of surface waters, on the ground 
 that the sewers are not then so thoroughly flushed as when provision is 
 made for the admission of the rainfall. Experience, however, has shown 
 that, where separate systems are carried out, there still exists a consider- 
 able influx of rain water from the back roofs of buildings and from 
 other impervious surfaces connected with dwellings, the off-flow from 
 which cannot practically be excluded fronj the private sewers communi- 
 cating with the public ones, which affor,ds ample jjieans of flushing 
 the sewers in times of rainfall, without the addition of surface waters 
 from public roads, front roofs, &c. Where separate systems do exist, 
 and the necessary storm overflow? are provided^ the discharge from 
 the sewers will still be four^d, in west weather, to occasion great 
 derangement. To meet this difficulty Osier Beds are provided in q^j^j. g^^j^^ 
 connection with Intermittent Filtration areas, through which the excess 
 passes, and by which it is freed from solid floating matter before reaching 
 the natural outfall. It is only in this supplemental way that Osier Beds 
 can be safely used. 
 
 The last ten years have taught us that the value first put upon liquid value of 
 sewage by Chemists (from i^. to 2^(i. per ton), though arrived at by the sewage, 
 most careful analysis and computations, is quite irreconcilable with 
 tangible results. The country was, indeed, led to expect that the sewage 
 of 20 persons might be sufficient to produce heavy c;:ops, and at the same 
 time maintain the fertility of an acre of land, whilst the estimate, which 
 gained general favour was, that with systernatic distribution, the sewage 
 of 100 persons to the acre wopld be att;,ended with certain profit ! At 
 the same time the value of the solid materials existing in sewage was 
 even more exaggerated by patentees and other persons. 
 
 Instead of liquid sewage being worth even a penny a ton, and the Value of 
 solid materials worth ;£^ a ton, ^s it was often asserted had been realised, 
 we find, as will be shown when treating of sewage farming, that the 
 utmost price given for the former has not reached one-third of a 
 
38 
 
 farthing a ton, while Dr. Voelcker, F.R.S., the Consulting Chemist 
 of the Royal Agricultural Society, has incontestably shown that the 
 money value of the dried sewage — "sludge'' — offered for sale after 
 treatment at Bolton, Bradford, and Leeds varies from ^i is. id. 
 to i6s. S^d. a ton, and is often unsaleable at any price. 
 
 The report of Messrs. Eawlinson and Read, the Committee appointed 
 by the late President of the Local Government Board, contained the 
 valuable report of Dr. Voelcker, setting forth these figures. It exposed 
 with singular force the almost worthless character of sludge when 
 separated from sewage liquid. In order to ascertain the value of the 
 fertilising properties of sewage and excreta, and also of the manures 
 manufactured therefrom, and of their commercial value to the farmer, 
 the Committee collected samples at Bolton, Bradford, Leeds, Coventry, 
 Rochdale, and Halifax, and caused them to be analysed, and the 
 following is the report referred to : — ■ 
 
 Dr. Voelcker's " On the Fertilising and Commercial Value of Sewage and Night-soic 
 Report on the Manures. — The fertilising and commercial value of sewage-sludge and 
 sewaee as °^ portable manures prepared from sewage, night-soil manures, and 
 
 a manure. of common farm-yard manure, chiefly depends upon the proportions ot 
 
 phosphate of lime, potash, and nitrogen which these fertilisers contain. 
 
 "These fertilising constituents of manures can be bought at the 
 present time in the form of concentrated artificial manures, such as 
 guano, bone dust, sulphate of ammonia, &c., at the following rates : — 
 
 Phosphate of lime at ... ... ... li/. per lb. 
 
 Potash at ... ... ... ... ... id. „ 
 
 Nitrogen calculated as ammonia at ... ... 8^. ,, 
 
 I need hardly say that in such concentrated forms, phosphate of lime, 
 potash, and ammonia have a much greater value than they possess in 
 the shape of manures, the bulk of which mainly consists of materials 
 without value, and occurring in abundance in almost every kind of soil. 
 
 " I would, however, direct attention to the fact that according to my 
 own experience and that of others, sewage manures, night-soil manures, 
 and ordinary farm-yard manure contain but little ready-formed ammonia, 
 and that by far the largest proportion of the nitrogen in these manures 
 occurs in them in the shape of nitrogenous organic matters in which 
 form nitrogen is less efficacious, and in consequence less valuable, than 
 in the form of ready-formed ammonia or salts of ammonia. 
 
 " In estimating the theoretical value of manures, the nitrogen is gene- 
 rally assumed to be present in sewage and similar bulky manures in the 
 form of ammonia, or, at all events, to have the same value as the nitrogen 
 in the salts of ammonia. This, in my opinion, is a mistake, and the nitro- 
 genous constituents of sewage manures are valued at too high a rate if 
 their nitrogen is calculated into ammonia, and M. allowed for each pound 
 of the calculated amount of ammonia. In order to avoid the charge of 
 having put too low an estimate upon the fertilising constituents of 
 
39 
 
 sewage-manures, I have allowed in the estimate 8^. per pound for the cal- 
 culated amount of ammonia which the nitrogenous matters in a ton of 
 manure are capable of gradually producing under the most favourable 
 circumstances on their final decomposition. 
 
 " The following Tabular Statement shows at a glance the theoretical 
 or calculated money value of the different sewage manures which were 
 submitted to me for analysis : — 
 
 "Theoretical or estimated Money Value of one Ton of the treated 
 Sewage Sludge. 
 
 £ s. d. 
 
 (i.) Bolton sludge — from the M. and C. sewage 
 
 process* ... ... ... ... ... o 9 85 
 
 (2.) The same dried, leaving 15 per cent, of 
 
 moisture in the sludge ... ... ... i i i 
 
 (3.) Solids drained from sewage before the liming 
 
 process at Bradford ... ... ... on o^ 
 
 (4.) The same with 15 per cent, of moisture ... o 19 3 
 (5.) Bradford Corporation Sewage Outfall Works, 
 sludge from drying pits, no artificial heaf 
 being used ... ... ... ... ... o 4 8 
 
 (6.) The same with 15 per cent, of moisture ... i o o^ 
 (7.) Deposit from the sewage of Leeds treated 
 
 by the A B C process o 8 4^ 
 
 (8.) The same with 15 per cent, of moisture ... o 16 Z\ 
 (9.) Manure produced by the General Sewage 
 
 Manure Company at Coventry ... ... o 16 9 J 
 
 (lo.) Rochdale Manure ... ... ... .. o 15 11^ 
 
 (11.) Manure manufactured by the Goux Com- 
 pany at Halifax ... ... ... ... 017 7 
 
 "According to the most reliable statements the separation of the 
 suspended matters of sewage by precipitation and filtration, and the 
 production of one ton of dried sewage deposits, apart from the costs 
 of the precipitation agents which are used, entails an expense of about 
 2,0s. for each ton of portable dried sewage manure. It is evident, 
 therefore, that the cost of manufacture considerably exceeds the theo- 
 retical or calculated money value of every one of the sewage deposit 
 manures, the composition of which is given in the results of analysis in 
 Appendices Nos. i, 2, and 3. The estimated money value of sewage and 
 night-soil manures, as has been stated already, does not fairly represent 
 their real commercial value. The bulk of all the samples submitted to 
 me for analysis consists of matters which occur in abundance in almost 
 all soils, and which at any rate have no commercial value, or rather have 
 a negative value, inasmuch as carriage has to be paid for them, and the 
 application, of bulky manures necessarily is more expensive than that of 
 concentrated manures, such as guano or bone dust. It is, therefore, 
 manifestly practically wrong to estimate the money value of such bulky 
 and poor manures by the same standard of prices at which the commer- 
 
 * M. and C. are the initials of the patentees. The ingredients used are lime, 
 carbon, housg ashes, soda, apd per-chlpride of iron. 
 
40 
 
 cial value of guano, bone dust, sulphate of ammonia, and similar con- 
 centrated artificial manures are estimated. A more rational and correct 
 estimate of the true value of sewage and night-soil manures is obtained 
 by comparing them with ordinary farm-yard manure, and the price which 
 is paid for the latter. 
 
 " Good farm-yard manure, I find, contains on an average in the ton 
 6^ lbs. of soluble phosphate of lime, 8^ lbs. of insoluble phosphate of 
 lime, 13 lbs. of potash, and nitrogen equal to 17^ lbs. of ammonia. 
 
 "By allowing for soluble phosphate of lime 2d. per lb., the same 
 price for potash, \d. per lb. for insoluble phosphate of lime, and %d. 
 per lb. for ammonia, the calculated money value of a ton of farm-yard 
 manure amounts to \^s. i\d., as will be seen from the following 
 figures : — 
 
 s. d. 
 6^ lb. of soluble phosphate of lime, worth at 2d. per lb. i i 
 8^ „ insoluble „ „ \d. „ o 8^ 
 
 13 „ potash ... ... ... ,, 2d. „ 22 
 
 Nitrogen, equal to 1 1\ lbs. of ammonia, calculating am- 
 monia at 8i/. per lb. ... ... ... ... ... II 8 
 
 Total calculated money value of a ton of farm-yard manure 15 7 ^ 
 
 "It thus appears that if we estimate the money value of good farm- 
 yard manure, according to the same rules at which the principal fertilis- 
 ing constituents in the dung can be bought in concentrated manures, 
 one ton of farm-yard manure would be worth in round numbers 1 5 J. 
 However, good dung can be bought in many places at 5^. per ton, or 
 one-third its estimated money value, and practically the highest price 
 which a farmer can afford to pay for good dung, if he has to cart it even 
 a few miles, would not exceed 7^^. dd. per ton, one-half its estimated 
 money value. The difference between the estimated money value of 
 farm-yard manure (calculated at the market rate of the constituents when 
 sold as concentrated artificial manures) and the actual market price may 
 be fairly taken to represent the difference in practical value caused by 
 the greater expense of the carriage and application of farm-yard manure, 
 and the less vigorous action of organic nitrogenous compounds as com- 
 pared with ammonia salts. 
 
 " In estimating the commercial value of sewage and night-soil manure 
 the calculated value of which does not exceed j[^\ \s. per ton, precisely 
 the same circumstances have to be taken into account which affect so 
 largely the market value of ordinary farm-yard manure. Accordingly 
 the price which the farmer can afford to pay for the sewage and night- 
 soil manures, analysed by me, or their real money value, will be only 
 from one-third to one-half that of the calculated estimates given on the 
 basis of their analyses. 
 
 " The following Table shows the market price or real money value 
 of the various sewage and night-soil manures, samples of which were 
 submitted to me for analysis. 
 
41 
 
 " Practical or Market Value of one Ton of the treated Sludge. 
 
 s. d. s. d. 
 
 (i.) Bolton sludge from the M. and C. 
 
 sewage process ... ... ... 3 3 to 4 10 
 
 (2.) The same sludge, 15 per cent, of 
 
 moisture ... ... ... ...70 „ 10 6 
 
 (3.) Solids drained from sewage before 
 
 the liming process at Bradford ... 38 ,,56 
 
 (4.) The same with 15 per cent, of mois- 
 ture ... ... ... ... 6 5 „ 96 
 
 (5.) Bradford Corporation Sewage Out- 
 fall Works, sludge from drying pits 
 without artificial heat ... ... i 6 ,, 2 4 
 
 (6.) The same dried with 15 per cent. 
 
 of moisture ... ... ... 6 8 „ 10 o 
 
 (7.) Deposit from the sewage of Leeds 
 
 treated by the ABC process ... 2 9 „ 42 
 
 (8.) The same sludge with 15 per cent. 
 
 of moisture ... ... ... 5 6 ,, 84 
 
 (9.) Manure produced by the General 
 Sewage Manure Company at 
 
 Coventry 56 „ 84- 
 
 (10.) Rochdale manure .. . ... ... 5 4 „ 80 
 
 (11.) Manure manufacture by the Goux 
 
 Company at Halifax ... ... 5 10 ,, 8 9 
 
 " In my judgment this tabular statement fairly represents the money 
 value of eleven different samples sent to me for analysis at the place 
 where the manures were produced. 
 
 " Some of the products are worth a good deal less than an equal 
 weight of common dung, which fully explains the circumstances that 
 most sewage manures find no ready sale even at a low price, and 
 that in many works such manures accumulate to an inconvenient 
 extent. 
 
 " Indeed, comparatively few farmers are so situated that they can 
 afford the expense of carting semi-dried sewage sludge, containing from 
 60 to 70 per cent, of moisture, from the works to their fields. The 
 refusal to accept such sludge as a gift in not a few instances rather 
 |hows sound discrimination than ignorance on the part of the farmers. 
 
 "(Signed) AUGUSTUS VOELCKER." 
 Liquid sewage will be found to have a value as an efHuent which Other uses 
 has not y^ be«n reduced to figures nor considered by sanitary au- sewage, 
 thorities. From the experience gained at Merthyr, Kendal, Abingdon, 
 Malvern, Halstead, and other places, some of which may be charac^ 
 terised as manufacturing towns, it -may be assumed with certainty thsit 
 by Intermittent Filtration through "suitably constitut^^d soil," somp 
 descriptions of liquid trade refuse may be purified at the rate of at 
 least 100,000 gallons to an acre of land, and brought to a condition 
 
42 
 
 that will make the effluent capable of re-use for trade purposes.In- 
 
 deed, the practice of Herr von Rath of Silesia, of concentrating the 
 
 Sewage underdrainage water of the land to which the foul liquid of his factory 
 
 effluent water j^g^^ been applied, and then raising it for re-use, may in many cases 
 
 trade pur- be favourably adopted in the busy northern valleys of this country, and 
 
 poses. there is no doubt that at some future period we shall find that in 
 
 districts where mills using large quantities of water are congregated, 
 
 a combined treatment of trade liquids will be adopted, in which this 
 
 view of the subject will prevail. 
 
 I cannot do better than reprint a translation of a letter I received 
 from Baron von Liebig, very shortly before his death. He said : 
 
 "Receive my best thanks for your letter of the 3rd inst., and for 
 the paper on Intermittent Filtration through natural soil. I have 
 read this with great pleasure and real satisfaction. . . . Your 
 plan for the purification of liquid sewage, and the removal of its 
 injurious qualities, as well as the technical execution of the plan, and 
 the use of sewage as manure, are alike excellent, and I only wish that it 
 may be made use of in other places. In Silesia, for some years past, 
 the best use has been made of your principles in the Beet-root 
 Sugar Manufactory of Herr von Rath. In the neighbourhood where 
 this manufactory is situated there is a want of spring-water, and of 
 water generally, and this want has called forth the following arrange- 
 ment : — All water that has been used in the manufactory, and generally 
 all waste or foul liquids, are discharged on to a well-drained piece 
 of land close at hand, and the filtered effluent water is collected in 
 a well. It is pure and clear, and it is again raised by a pump, and used 
 in the manufactory as fresh water." 
 
 Use and value This is a good practical illustration of the use of sewage water when 
 rtf sewage purified ; and there is every probability that the power of so utilising 
 
 liquid for , ,. , 
 
 watering. effluent water may be realised at Dewsbury, where the sewage, after 
 
 passing through the filter beds laid out to cleanse it, may be seen flow- 
 
 into the Calder, cleaner than the river water itself? But there is 
 
 another use, which, though acknowledged generally to be of value, has 
 
 been so mixed up with the practice of Surface Irrigation as to lose its 
 
 speciality. There are times in the year when all farmers would value 
 
 highly the acquisition of water (apart from manure) to invigorate their 
 
 growing crops, and it is one of the objects of this treatise to show that 
 
 by a proper arrangement for distribution the use of sewage for watering 
 
 may have its place. A farmer in a dry year would pay more for a 
 
 timely watering with sewage than he would for any quantity of Hquid 
 
 manure in a wet one, 
 
43 
 
 II. THE QUANTITY AND USE OF THE SOLID 
 MATTERS FLOATING IN SEWAGE. 
 
 The quantity of the solid portions present in sewage varies con- Character and 
 
 siderably, and it is increased in proportion as trade refuse is admitted g^uj jjLf^. 
 
 into the sewers. The floating ingredients exist in three gradations of lien's of 
 
 sewage, 
 weight and size. 
 
 In the first are included the bulky substances which would interfere 
 with the valves of pumps if the sewage were raised, and would be offen- 
 sive and obstructive to plant growth if distributed on the surface of land. 
 They consist of almost every imaginable thing that could be thrown into Heavier 
 a sewer, and they are generally arrested and extracted by screening. P™ '°"^' 
 Not being of any large aggregate quantity they are readily removed when 
 screened out of the sewage. 
 
 In the solids of the second gradation are included the smaller but Road detritus, 
 heavy substances which, after passing through a screen, quickly sink by 
 their weight to the bottom of any tank or receptacle while the sewage is 
 in motion. They include road detritus or sand, which being valuable in 
 itself may be separated from the lighter substances by mechanical 
 deposition and utilised. 
 
 The suspended substances of the third gradation, frequently called sludge. 
 " sludge," comprise the organic matter and those minute inorganic sub- 
 stances, including very fine sand, which float onwards and deposit them- 
 selves very slowly even when the containing liquid is in a quiescent 
 state. When the sewage is in motion the precipitation of these 
 minute substances can only be readily effected by mixture with certain 
 chemicals. 
 
 At Birmingham, where the outflow of sewage is about 12,000,000 
 gallons daily in dry weather, and lime has been used as a precipitant 
 mixed with the sewage at the rate of 23^ cwt. per million gallons, the 
 road detritus and sludge, together with the lime, amount, on an average, 
 we are told, to about 360 cubic yards daily. Such, however, is the 
 worthless character of the " sludge " that no one will take it away at a 
 gift, and it is therefore dug into land forming part of the Saltley Farm 
 and buried out of sight, at the cost of ^i 2 per acre. 
 
 Of sludge alone the quantity would seldom exceed 100 grams per 
 
44 
 
 gallon, and it is the existence of this material in combination with more 
 or less road detritus that has been made an objection to the use of 
 land for the cleansing of sewage by representing it as " clogging " its 
 pores. 
 
 If properly distributed on carefully prepared surfaces sludge on land 
 generally does good rather than harm ; in fact, it only has an objection- 
 able effect when it is mixed with particular trade refuse. Dispassionate 
 inquiry would satisfy all persons that the difficulties stated to exist on 
 account of sludge are imaginary. Harm sonietimes occurs in surface 
 irrigation when the quantity of solid matter is large, — such as is occa- 
 sionally the case when storms wash out the sewers after accumulation 
 of solid matters during drought, — and when it is allowed to settle in 
 hollows on the surface of carelessly formed land to kill growing vegetation, 
 and, possibly, to give off effluvium. Injury to vegetation is most 
 likely to occur, under such circumstances, when solid trade refuse is 
 admitted into sewers. 
 
 As the opinion now generally prevails that artificial treatments of 
 sewage are only admissible when land cannot be obtained, it should be 
 known that experience has shown that " sludge " is not a bar to the 
 application of sewage to land. It is only necessary to remember that 
 " sludge " consists of vegetable and animal substances which are perish- 
 able, mixed with earthy and mineral substances in very small particles 
 which are not perishable, to realise the fact that they cannot possibly clog 
 land when dry. The most minute particles consist of fine road sand which 
 float on in the liquid after the heavier detritus has deposited itself. 
 When these perishable and imperishable substances find their way into 
 the interstices of the soil they must each, from their nature, obviously 
 add to its porosity, inasmuch as the perishable substances leave open 
 spaces as they decay, whilst the imperishable substances from their 
 gritty nature necessarily help to increase its filtering capability. So 
 long as the sludge is wet it impedes absorption to a certain extent, but 
 when once dried and the land broken up by the plough, the scarifier, or 
 the spade, it not only ceases to uphold the liquid, but naturally and per- 
 manently helps to let it into and through the soil. 
 
 In Intermittent Downward Filtration, the deposit of the sludge takes 
 place in the furrows, which form an essential feature in the system, and 
 we find in practice that when first used the furrows themselves absorb 
 the sewage too quickly, but that as the deposit of sludge accumulates 
 in them they resist infiltration and the sewage is driven into the ridges 
 
45 
 
 on each side and so distributes itself more equally than if the furrows 
 
 alone absorbed it. As soon as the deposit of sludge on the sides of the 
 
 furrows is sufficient to prevent infiltration in any great degree, the sewage 
 
 is withheld from the areas so affected. The sludge is then allowed to sludge bene- 
 
 dry (partially) in the furrows, and when in a fit condition it is lifted and ' / '•° " 
 
 dug into the ridges, — as can be seen practised at Gennevilliers (Paris). 
 
 The slimy matter which had appeared so considerable, and which 
 
 puddled the bottom of the furrows, when in a wet state, shrinks to a 
 
 skin of very insignificant thickness when dry, and is readily broken up 
 
 and mixed with the soil. 
 
 Experience has shown that sludge (with such fertilising ingredients 
 as it contains) cannot be more cheaply conveyed to places where it 
 would be beneficial than by the liquid sewage itself. The very trifling 
 value of the suspended ingredients renders.it all the more desirable 
 that they should be disposed of by the same means and at the same 
 time as the liquid. 
 
 The objection raised to the distribution of sewage, containing solid Objection to 
 ingredients in suspension amongst growing plants because the solid ^^^^ ^f fj^^^ 
 matters will cling to their stalks and leaves, vanishes altogether when matters among 
 
 growing vege- 
 
 furrows are made the channels of distribution, and when no more tation. 
 sewage is distributed on the surface of land than the land will absorb 
 and vegetation requires. It is only when the pernicious practice of 
 flooding land is resorted to that sewage will rise up among the stalks 
 and leaves growing upon it. At Gennevilliers the sewage never touches 
 the vegetation growing in the irrigated ground. It is distributed through- 
 out the entire breadth of the plains in furrows in precisely the same way 
 as in Intermittent Filtration designedly practised as such in this country. 
 
 III. THE TEMPERATURE OF SEWAGE. 
 
 An objection is often raised, that frost acts as a bar to the distribu- Temperature 
 tion of sewage on the surface of land in the winter seasons. Mr. William ° ^^"'^S^' 
 Haywood, the Engineer to the City of London, having carefully ascer- 
 tained the temperature of the internal air of sewers, and compared it 
 with that of the external air for a whole year, found the mean winter 
 temperature of the former to be 1 1 •6i degrees higher than the latter. In 
 summer the sewer air was 3"i2 degrees colder than the outer air. 
 
46 
 
 The following Table gives the comparative figures :- 
 
 
 Temperature in external 
 atmosphere in shade. 
 
 Temperature in 
 
 sewer. 
 
 Time of Year. 
 
 
 
 
 
 Highest. 
 
 Lowest. 
 
 Mean. 
 
 Highest. 
 
 Lowest. 
 
 Mean. 
 
 
 o 
 
 
 
 
 
 
 
 
 
 
 
 Summer 
 
 72 
 
 55 
 
 65-04 
 
 68 
 
 S6 
 
 61-92 
 
 Winter 
 
 34 
 
 30 
 
 32-37 
 
 52 
 
 ■40 
 
 43 '98 
 
 Spring 
 
 61 
 
 46 
 
 52-46 
 
 59 
 
 48 
 
 52-52 
 
 Autumn 
 
 68 
 
 48 
 
 59 '90 
 
 70 
 
 53 
 
 62-97 
 
 Average of the whole year 
 
 
 ... 
 
 50-24 
 
 
 
 55-35 
 
 The Sewage Committee of the British Association ascertained at 
 Merthyr that on the coldest day during the time the observations were 
 made, the difference between the temperature of the sewage delivered to 
 the filtration areas, and that of the air was 8 degrees, while the tempera- 
 ture of the effluent water discharged from the underdrains was found 
 to be I degree higher than sewage itself. The observations here given 
 were made for eight days in January, and in July, 1872. They were 
 recorded as follows : — 
 
 
 Temperature. 
 
 Date. 
 
 Temperature. 
 
 Date. 
 
 At Noon. 
 
 Average 
 during day. 
 
 At Noon. 
 
 Average 
 during day. 
 
 
 .is 
 <! 
 
 s 
 
 
 
 Is 
 
 < 
 
 
 
 en 
 
 
 1872. 
 
 °F. 
 
 °F. 
 
 "F. 
 
 °F. 
 
 1872. 
 
 °F. 
 
 °F. 
 
 °F. 
 
 "F. 
 
 Jan. 9 
 
 
 
 49 
 
 46 
 
 July 2 
 
 70 
 
 63 
 
 60 
 
 56 
 
 ,, 10 
 
 50 
 
 49 
 
 49 
 
 46 
 
 ,. 3 
 
 70 
 
 64 
 
 60 
 
 55 
 
 ,, II 
 
 49 
 
 48 
 
 50 
 
 47 
 
 .. 4 
 
 75 
 
 73 
 
 60 
 
 55 
 
 „ 12 
 
 48 
 
 46 
 
 484 
 
 45 
 
 » 5 
 
 69 
 
 70 
 
 60 
 
 56 
 
 ,, 13 
 
 49 
 
 47 
 
 47 
 
 4Si 
 
 ,, 6 
 
 68 
 
 70 
 
 55 
 
 68 
 
 „ 14 
 
 50 
 
 49 
 
 48 
 
 46 
 
 » 7 
 
 68 
 
 64 
 
 60 
 
 55 
 
 ,, 15 - 
 
 40 
 
 38 
 
 43 
 
 45i 
 
 „ 8 
 
 68 
 
 44 
 
 60 
 
 55 
 
 „ 16 
 
 37 
 
 39 
 
 45 
 
 46 
 
 » 9 
 
 68 
 
 50 
 
 60 
 
 55 
 
47 
 
 These and the previous figures prove that the distribution of sewage 
 on land is not likely to be much impeded by frost, and that when 
 collected in furrows, as is the case in Intermittent Downward Filtration, 
 the sewage will thaw the frozen condition of land with which it may Frost. 
 be brought in contact. This is found to be particularly the case where 
 the sewage is distributed by furrows in contradistinction to surface 
 spreading. 
 
 The Rivers Pollution Commissioners in their examination of the 
 effluent water from the Croydon Sewage Farm^ on the surface of which 
 the sewage is spread by wide irrigation, found that during frost in winter 
 it was slightly, but only slightly, less pure than at other times. 
 
 IV. STORM OVERFLOWS. 
 
 The outlets called storm overflows cannot be done without ; they storm over- 
 are the safety valves essential to all systems of sewerage and sewage ^°'"^- 
 disposal. It is not sufficient, however, to declare that when the sewers 
 of towns are overcharged by the dilution due to rainfall they should 
 come into operation as a matter of course. It is true that the volume 
 of rivers is at such times also increased by the off-flow from tributary 
 ground surfaces and that their waters cannot be made much worse than 
 they then are. Nevertheless there must be a limit to the frequency 
 with which rivers may be thus occasionally polluted. 
 
 Experience has not afforded any clue to that limit beyond establish- 
 ing the fact that no mode of cleansing sewage by tank treatment or by 
 irrigation over, or filtration through land, can be effective when the 
 sewage is diluted by rainfall beyond a certain amount. One inch of rain 
 thrown off loo acres equals 2,262,200 gallons, and if one-tenth of this 
 quantity suddenly reaches the outfall^say, in half an hour — no mode of 
 treatment yet devised can deal with such a quantity without injury or 
 defect. It is easy enough to deal with an outflow from sewers if the 
 quantity be constant and is ascertained, but it is quite beyond the powers 
 of any engineer to devise a means of treating liquids swollen by sudden 
 and extraordinary dilution. If therefore the law refuses to recognise storm 
 overflows from sewers because when called into action they cause 
 some pollution, no national advantage would be gained, inasmuch as the 
 incapability of cleansing sewage when swollen to the extent mentioned 
 
48 
 
 would involve an overflow of an equally injurious character from the 
 
 I land or works intended in ordinary times to cleanse it. 
 
 Osier beds ' Osier Beds may be usefully connected with Storm Overflows where- 
 
 deanslne of ^^^*^ ^^ latter are necessary on Sewage Farms to discharge such 
 
 storm waters, waters as are suddenly thrown down upon them in excess of what 
 
 the land has been intended to absorb. Several instances of this use 
 
 of Osier Beds will be found in the following pages, but it should 
 
 be clearly understood that they are not here proposed to do the 
 
 service suggested in the Official Report already referred to in which it 
 
 is stated that — 
 
 "A portion of each farm should be specially deep-drained and 
 prepared for land-filtering the sewage during the winter and wet 
 weather. When these filters," it is said, " are laid out in ridged beds, 
 some roots and vegetables can be raised with success, as the sewage 
 generally flows down the channels. But in times of floods and 
 storms the sewage may rise above the beds, so that perhaps osiers, 
 which would not be damaged by being flooded for days, would be 
 the safest and therefore the most profitable crops to grow upon them." 
 
 These words must have been inadvertently published, for it is 
 hardly possible that the authors of the Report could really have supposed 
 that filtration areas when growing roots and vegetables on ridges were 
 liable, under proper management, to be flooded, or that underdrains, 
 which are positively essential to filtration, would resist the ingrowth of 
 Osier roots, which have a singular aptitude for filling undergrains, what- 
 ever may be their depth. Filtration areas, properly constructed, are 
 less subject to floods than other land designed for the reception of 
 sewage, and the surest way of rendering them useless would be to plant 
 osiers over the underdrains to fill them with their roots. Underdrains 
 should be kept free of all possible obstruction. 
 
 Osier Beds, to be useful, on Sewage Farms, should be connected with 
 Storm Overflows, so that excesses may run through them. The beds 
 are formed in horizontal areas which serve to check the rapidity of flow 
 of suddenly discharged rainfall. This check causes the deposit of the 
 floating solid matters in the furrows, while the flood-water rises and 
 overflows the ridges and the osiers growing on them. These beds are 
 not underdrained in any way; their simple purpose being to clarify 
 those excess-waters which without the check afforded by them would 
 be impetuously discharged, together with everything floating in them, 
 into the natural streams of the watershed. 
 
49 
 
 Y. THE CHARACTER OF LAND MORE OR LESS 
 SUITABLE FOR SEWAGE CLEANSING. 
 
 Speaking generally, the greater the natural fertility of land the more 
 suitable it is for Surface Irrigation, inasmuch as the stimulation of plant 
 growth, resulting from a covering of liquid, can only be maintained 
 under varying conditions by natural productive power. This is evidenced 
 on every Sewage Farm, even after it has been irrigated for years, by the 
 superior growth of crop on one part compared with another receiving 
 the same quantity of sewage. Poor land can be made productive slowly 
 by the process of irrigation, but it is found that the best return from a 
 given outlay is gained from a soil naturally fertile. 
 
 The most suitable soil for both Irrigation and Filtration is a sandy Suitable and 
 loam with a small proportion of gritty gravel to quicken percolation. ™jj^' ^ ^ 
 The soils most unsuitable are very dense clays, bog peat, and very 
 coarse gravels. All soils which absorb and retain water, and which are 
 therefore subject to expansion as they receive, and contraction as they 
 part with it, will crack, and any liquid applied to the surface will descend 
 by the cracks as far as they reach. In stiff clays these cracks extend 
 to the drains and the liquid poured on the surface will pass away by the 
 drains to the rivers and streams in a condition almost as foul as when it 
 was applied. Loams with a small portion of clay are not subject Loams, 
 to the same drawback if the surface soil is mixed with burnt earth 
 and is deeply cultivated. The superior properties of loamy land, pro- 
 perly drained, consist in the affinity for ammonia which its clay consti- 
 tuents possess, and the extreme comminution to which it is reducible 
 by the action of air and water. Under proper treatment a loamy soil 
 becomes, not only more productive of vegetation, and therefore a better 
 purifier of sewage, but it constitutes a better filtering material 
 (mechanical) than either gravel or coarse sand. Clay soils are not to ciay soils, 
 be recommended for Surface Irrigation, and can only be used for 
 Filtration by an outlay in draining, earth burning and mixing, which 
 Sanitary Authorities are indisposed to expend. 
 
 The best soils for Intermittent Filtration are those of a free character 
 closely pulverised with such a proportion of alumina equally dis- 
 persed through their bulk as does not exceed 7 per cent, of their con- 
 
 D 
 
50 
 
 Absorptive 
 and retentive 
 powers. 
 
 stinients. Sewage will pass but slowly through such description of soil, 
 and they therefore require quickening by carefully designed under- 
 drainage to overcome their natural retentiveness. Soils of this descrip- 
 tion will probably contain from 80 to 90 per cent, of insoluble silicates 
 and sand by the chemist's analysis. 
 
 The capacity of soils to absorb water is no criterion whatever of their 
 cleansing capability, whilst their retentive powers exercise great influence 
 on the rate of percolation and the quality of the effluent. A coarse 
 gravelly soil thoroughly drained, for instance, will absorb and discharge 
 liquid almost as quickly as it reaches its surface and will give out an effluent 
 but imperfectly purified, whereas a loamy soil, having a sufficient pro- 
 portion of sand to render it free and to fill it with close interstitial spaces 
 for aeration, will discharge a satisfactory quantity of purified water by 
 the underdrains and maintain a very superior effluent. 
 
 Experience conclusively shows that while some soils, even in 
 their natural unmoved condition, will let sewage pass through them too 
 quickly, others have retentive powers — I speak of clay and peat soils — 
 which not only retard in an unfavourable degree the passage of 
 water through them, but in some degree injuriously affect the effluent 
 itself by rendering it cloudy or discoloured, though not chemically 
 objectionable. 
 
 The effect of pouring liquid on soils when charged by attraction is to 
 drive out by the fresh liquid that which is already in possession of their 
 interstitial spaces, and as these spaces can hardly be said to be perfectly 
 aerated (though it can only be by the influence of the atmosphere 
 existing in the soil that the water is driven out), the action is not as per- 
 fect as desirable. A peaty soil is the most retentive and at the same 
 time the most absorbent of soils. It will hold water of greater weight 
 than itself, but it readily yields when in this saturated condition to 
 the gravitating force of liquids applied to the surface. Clays of the 
 denser nature — such as the London Clay in situ, the Stiff Clay Beds 
 of the New Red Sandstone, and the Boulder Clay overlying the 
 Oxford Clay, and others absorbing water weighing as much as one- 
 third to one-half of their own weight, according to their undisturbed or 
 broken condition — will stubbornly resist its passage through them. It is 
 this condition that renders them the most unsuitable of all soils for 
 filtration, though by burning and mixing they may be rendered available 
 at a cost which though comparatively great may yet be less than that of 
 other treatments. 
 
51 
 
 Closely related to the absorptive and retentive powers of soils is their Evaporation, 
 evaporating property, the effect of which at certain times of the year is 
 so great that in cases where there is no subsoil water to dilute the 
 effluent, the quantity discharged has been less than half the quantity of 
 the sewage distributed over the surface. I make this statement having 
 heard it often observed that the measure of the effluent in such cases 
 will accord with the quantity of sewage cleansed. 
 
 1. MERTHYR TYDFIL, SOUTH WALES. 
 
 Commencing the instances I desire to describe with that of 
 Merthyr Tydfil, which has been so ingeniously misrepresented in 
 Counsels' speeches, witnesses' evidence, published papers, and official 
 reports, I trust to free the matter of much of the doubt with which it 
 has been surrounded, by the relation of facts that have been established 
 and which are still to be studied with advantage. They will fully 
 establish both the soundness of Dr. Frankland's theory of Intermittent 
 Downward Filtration, as expressed in the report of the Rivers Pollution 
 Commissioners, and the success of the works founded on that theory, 
 which were carried out at Troedyrhiew on my report to the Lords 
 Justices of Appeal in the following year (1871) at some risk to my 
 reputation as a practical man, in consequence of the hesitation to 
 recommend its adoption manifested by the Commissioners themselves. 
 
 As early as April, 1869, Mr. Samuel Harpur, the Local Surveyor of Works 
 the district, proposed to the Local Board a scheme which they approved "^^de/by 
 for utilising the sewage of the district by surface irrigation. The land Local Board, 
 intended to be taken consisted of 375 acres in the valley of the TaiF; of 
 which one block, containing about 75 acres, was situated at Troedyrhiew 
 within a quarter of mile of the village of that name, and about two miles 
 from Merthyr Tydfil, and the remaining 300 acres, eight or ten miles 
 lower down the valley, and to which the sewage was to be conducted by 
 an outfall sewer of a very costly character. It was in consequence of 
 the heavy character of the irrigation works and outfall sewer, and the 
 time which would be taken to perfect them, that proceedings in 
 Chancery were taken by certain riparian owners who desired that the Proceedings 
 pollution of the River under which they suffered should be prevented ^.ncery. 
 
52 
 
 Interim 
 remedy 
 adopted. 
 
 Cost of 
 interim works 
 misrepre- 
 sented. 
 
 during construction, and the appearance of the writer on the scene was in 
 consequence of his being appointed by the Lords Justices to effect the 
 remedy. The treatment suggested for this temporary rehef was Inter- 
 mittent Downward Filtration as propounded by the Rivers Pollution 
 Commissioners. The writer selected for this purpose 20 acres of 
 the free soil, of which he found the 75 acres at Troedyrhiew to consist. 
 The population of the Merthyr district was stated, in 1871, to be 
 about 50,000, of which the sewage equivalent to that from 25,000 
 persons found its way into the sewers discharging at Troedyrhiew. The 
 total dry weather outflow at the same date varied from 700,000 to 
 upwards of 1,000,000 gallons daily, increased in wet weather to 
 2,000,000 gallons. 
 
 The selected 20 acres were divided into four areas of five acres each, 
 which it was intended should be drained seven feet deep, but which 
 depth, owing to the work being imperfectly done, was not quite gained. 
 The mean depth, however, gave two cubic yards of drained, but not 
 necessarily perfectly aerated, soil for every square yard of surface. 
 Thus every plot of five acres contained 48,400 cubic yards of filtering 
 material. 
 
 To convey the sewage of Merthyr from the tanks which then 
 existed to this land (the 20 acres) involved the construction of a delivering 
 conduit of considerable length, available also for the remaining 55 acres 
 of land forming the Troedyrhiew Farm. The drainage of the land 
 and the preparation of the surface were undertaken by a contractor 
 not specially acquainted with land operations, and were therefore so 
 unsuitably executed in the first instance that, upon complaints 
 being made, the writer was called upon by the Lords Justices to 
 take the work under his own immediate supervision and to rectify 
 and complete it. It need hardly be said that a long length of delivery 
 conduit designed for the service of the whole farm of 75 acres and the 
 re-execution of a considerable part of the drainage and levelling 
 increased considerably the cost of the works of preparation; — and that the 
 amount should hardly have been charged against the 20 acres only. 
 Reference is made to this because the large outlay involved has been 
 published, and is often quoted by opponents as a reason why Intermittent 
 Downward Filtration should be avoided. It is, consequently, necessary 
 in the interests of sanitary science that the facts should be known, 
 particularly as from some inexplicable cause no opportunity was given 
 the writer by Messrs. Rawlinson and Read of explaining the facts when 
 
53 
 
 in the course of their inquiry into the several modes of treating town 
 sewage they visited Merthyr, and having obtained certain figures, sent 
 them forth to the public without stating the attendant circumstances. 
 
 For five months the sewage, equivalent to that of 25,000 persons, Effluent 
 was put on the 20 acres, and it was so effectually cleansed, that when ^"^'y^^f^- 
 Dr. Frankland analysed the effluent on the 20th of October, 1871, the 
 amount of organic nitrogen was found to be -012, and the amount 
 of ammonia "025, of one part in 100,000 parts. In 1872 the same 
 eminent chemist, confirmed by Drs. Benjamin Paul and Russell, found 
 the amount of organic nitrogen to vary from "014 to -033, and the 
 ammonia from '060 to '095. See Standards previously given. 
 
 The filtration areas, though laid out as a temporary expedient. The 
 did their work so completely that it soon became apparent that if the parnf am'!"' 
 whole of the comparatively small farm of Troedyrhiew (75 acres) had sufficient of 
 been properly prepared it would have been ample in itself to have Merthyr alone, 
 cleansed the whole sewage of Merthyr for the next 30 years without 
 recourse to the 300 acres of distant land.* 
 
 * Extract from Evidence given by Mr. Harpur, before the Rivers 
 Pollution Commissioners, in 1872. 
 
 Q. What do you suppose to be the population draining out of your exit (at 
 Troedyrhiew), what number of people? A. The number of people directly con- 
 nected with the sewers is about 20,CXX), but they are increasing now, and we are just 
 extending the drains. — Q. As regards the drainage from the other 30,000 or 40,000, 
 what proportion of their drainage, under this unconnected system, also finds its way 
 into the exit? A. As far as the bulk or quantity of drainage goes, I believe it will 
 be found, when the drains are connected, that the increase will be comparatively 
 slight. — Q. What proportion of the personal waste of this unconnected population at 
 present finds its way into the sewers, do you suppose ; I mean of the excrementitious 
 matters ? A. \ daresay a third of the excrementitious matters of the population not 
 connected directly with the drains gets into the sewers. — Q. The excrementitious 
 matter from 30,000 people ? A, Yes. — Q. Do you agree with Mr. Bailey-Denton, in 
 supposing that the filtration works below Troedyrhiew are incapable of dealing 
 with more than one-third of additional inhabitants ? ^. I do not agree with that, 
 I do not think that Mr. Bailey-Denton puts it as a matter of course, but he merely 
 gives that to keep himself within safe limits. — Q. How much additional waste do you 
 think the whole of the land is capable of defecating? ^. I do not think we can 
 suppose that the zo acres and the 50 acres are capable of taking more than they are 
 taking now, I think they are sufficiently sewaged. — Q. You mean sufficiently in the 
 interest of the crops? A. Yes. — Q. Did you notice when the whole of the sewage 
 was being passed on to the 20 acres, any tendency for the land to choke up ? A. No. 
 — Q. You have said that you thought the 2C acres would not cleanse much more than 
 
54 
 
 In fact it is certain that iiad not the notice of purchase been already 
 served on the Landowners, and the works themselves commenced, the 
 Local Board of Merthyr would, as soon as the effect of the filtration 
 works was seen, have limited their operations to the Troedyrhiew Farm 
 alone. 
 
 That I am justified in stating this will appear from the following 
 figures : — 
 The effect on From the best information I can collect, I am led to believe that 
 
 payers ^of ^^^ actual outlay in preparing the Troedyrhiew Farm (75 acres) was 
 
 Merthyr. _;^6,ooo, including the delivering conduit, the preparation of 20 acres 
 
 for filtration (some of the work being done twice over) and the 
 subsequent laying out of the 55 acres for irrigation. To repay this 
 outlay, the annual charge would be ;!^3oo a year. It is quite certain 
 that if the filtration work had not been subject to the disadvantages 
 to which I have referred, the outlay might have been much less ; — in 
 fact the whole 75 acres might have been drained, and laid out for 
 intermittent filtration for no greater sum than was unfortunately expended 
 in the combined arrangement. The rent (or annual charge) paid by the 
 Board for the 75 acres, I was given to understand would not exceed 
 £,Z1S to ;^38o a-year. Putting the land and works together, the total 
 annual charge upon the ratepayers of Merthyr if the expenditure had 
 been confined to the 75 acres at Troedyrhiew would have been at this 
 moment ;^68o a-year, or nearly J[^() an acre. The return of money from 
 the crops raised from the whole of the Troedyrhiew Farm may be certainly 
 taken to have reached an average income of ;^2o per acre, or ;£^i,Soo 
 a-year, owing to the local demand for grass and vegetables being quite 
 equal to the supply produced by the farm. The net return, after 
 payment of seeds and labour, which maybe taken at ;^io an acre, would 
 in such case certainly meet the outgoing of ;^68o a-year, required to 
 discharge the cost and preparation of the land. By this course of pro- 
 ceedings the ratepayers of Merthyr Tydfil might have been saved the 
 whole of the rates they have now to meet in consequence of possessing 
 
 the quantity you put upon it as a maximum ; on what grounds do you say that 1 A.\ 
 say that under the present arrangement it might be so, because if we put much more 
 on than we are now using, we should damage the vegetation instead of improving it. 
 — Q. But suppose you decided upon sacrificing the vegetation, what would your 
 opinion then be ? A. Then I think that we might cleanse the whole of the sewage of 
 the town. — Q. I think you have stated that you had not noticed any sign of the land 
 being overdosed. A. No, not so lar as the cleansing is concerned. 
 
55 
 
 the distant land, and "sewage farming" would not have another 
 instance of failure recorded against it, which, in the interests of 
 agriculture, is so much to be regretted. 
 
 It has been attempted to disparage the results arrived at by 
 asserting that there exists in the Valley of the Tafif a large 
 quantity of subsoil water which dilutes the infiltrated sewage, and that 
 the analyses do not therefore represent a condition of effluent which 
 would generally be found issuing from the underdrains of intermittent 
 filtration areas. There is no doubt that there is some truth in this 
 statement, but inasmuch as there is very little valley land in Great 
 Britain, by which sewage could be cleansed, which is not subject to 
 subsoil water in a greater or less degree, the fact of its existence rather 
 favours than disparages the adoption of the process, for the more the 
 filtered sewage is diluted, the more nearly it approaches a condition 
 admissible into rivers. 
 
 That the success of the works at Merthyr is not to be set aside Remarkable 
 by disparagements of this sort has been very appositely proved the°uccess 
 by certain circumstances very recently communicated to me by achieved. 
 Mr. T. J. Dyke, the Medical Officer of the district of Merthyr Tydfil, 
 whose interest in sanitary science is only equalled by his earnest desire 
 to represent the true facts of the case. He states in his letter, dated 
 the 9th September, 1880, that " the filtration areas," which have been 
 so persistently stated to have merged in the surface irrigated farm, in 
 spite of the assertion of Mr. Jones, the Chairman, to the contrary, " are 
 constantly used." 
 
 " On more than one occasion during the last three years the 20 acres 
 prepared by you have had to take the whole of the sewage of 40,000 people 
 for two, three, or more weeks together. The necessity for this has been 
 on each occasion caused by the breakage of the sewage channels which 
 were devised for the conveyance of the sewage to the lands below 
 Navigation Junction. On each of these occasions the areas did their 
 work thoroughly." 
 
 Upon my asking the writer, subsequent to the receipt of this letter, 
 whether he did not mean that the sewage of the 40,000 people was 
 filtered through the 75 acres constituting the Troedyrhiew Farm, he 
 replied : 
 
 " I mean that the 20 acres virtually took the sewage in emergencies 
 from the sewers above Troedyrhiew. Some portion might be sent over 
 the other 55 acres, but this must have been small, as those portions of 
 the land at Troedyrhiew are let out for grazing and for the growth of 
 
56 
 
 Italian rye grass, so that virtually the bulk of the sewage had to be dealt 
 with by the 20 acres." 
 
 But complete as this proof is of the value of Intermittent Filtration 
 as a safety-valve, the most unquestionable evidence of the efficacy of 
 filtration through natural soil is to be gained from the circumstance that 
 the Sanitary Authority of Merthyr Tydfil has admitted or has arranged 
 to admit the sewage of the several neighbouring districts of Aberdare, 
 Mountain Ash and Treharris (Quakers Yard), with a joint population 
 equal to that of Merthyr itself (making the aggregate population amount 
 to nearly 100,000), on to a less area of land than was designed in 1869 to 
 take the sewage of Merthyr Tydfil alone ! I state this on the authority of 
 Mr. Harpur, who, in the evidence he gave at the Lower Thames Valley 
 Main Sewerage Inquiry, stated that the combined authorities of Merthyr 
 Tydfil, Aberdare, Mountain Ash, 5z:c., with the population already stated, 
 was being dealt with on 212 acres, including the 75 acres at Troedyrhiew. 
 At the same time he showed that the whole of the 212 acres was not 
 laid out for Intermittent Filtration, but was partly utilised for surface 
 irrigation ! By this combination of districts and reduction of area 
 (which would never have been attempted but for the experience gained 
 in Intermittent Filtration at Troedyrhiew) the charge upon the rate- 
 payers of Merthyr, though still great in comparison with what it would 
 have been, had the Troedyrhiew land only been utilised, will be reduced 
 to less than half what it would have been had the original intention of 
 1869 remained in force, thus affording the most tangible evidence that 
 could be produced of the true value of Intermittent Filtration which in 
 the first instance was regarded with derision and which is still held up 
 by its opponents as an object for public distrust. 
 Treatment o( It is not long since Mr. Norman Bazalgette, in a paper he read at 
 
 the Institute' ^^^ Institution of Civil Engineers, made use of these extraordinary 
 ofC.E. expressions: 
 
 " Surely it is time that the Merthyr fallacy is stamped out, and yet 
 the advocates of Intermittent Downward Filtration seem unwilhng that 
 it should die. The statements with regard to Merthyr are without 
 foundation or justification." 
 
 How strangely will these words read side by side with the experiences 
 just related ! Having commenced my apprenticeship to agriculture 
 more than fifty years back, and having joined the Institution of Civil 
 Engineers nearly forty years back, — during which term I have not been 
 idle in engineering works of the kind criticised, — I shall be exonerated 
 from unworthy egotism if I meet expressions aimed so directly at 
 
57 
 
 myself by declaring that I esteem the opportunity I have had at 
 Merthyr Tydfil of giving substantial evidence of the soundness of 
 Dr. Frankland's views on Intermittent Filtration through natural soil as 
 the most fortunate incident of my life. This satisfaction is based 
 on the conviction that it will be only by the adoption of the process in 
 one shape or other, that the reproductive value of human refuse will be 
 realised for the benefit of the country. That the people of Merthyr 
 do not partake in Mr. Bazalgette's opinions is evident by the last words 
 of Mr. Dyke's recent letter. He says : — 
 
 " The feeling in Merthyr " (after ten years' observation) " is that the 
 filtration areas at Troedyrhiew were an engineering success. They did 
 the work designed for them perfectly. The process you devised is the 
 right one, and I earnestly hope the authorities of towns will adopt it." 
 
 With these facts recorded it is unnecessary to ask whether they 
 do not incontestably prove that the sewage of i,ooo persons may 
 be permanently cleansed on an acre of suitable land properly laid out 
 and properly drained 6 feet deep in spite of the opinion of Mr. 
 Harpur, often quoted by detractors though unsupported by any proof 
 whatever, that the capability of soil to cleanse sewage is limited to 500 
 persons to the acre. 
 
 To enable the readers of this treatise to form their own opinion, I 
 append an extract from a letter written by Mr. Harpur to me on the 
 9th of March, 1872, before he became committed to the opinion referred 
 to, in which he says : — '■ 
 
 " You know my objections to your Merthyr scheme were due 
 chiefly to its interference in some measure to my plans, but all that is 
 passed, and having carefully watched the process of Intermittent 
 Filtration in operation here and observed its marked success, I should 
 be fostering a prejudice if I hesitated to give evidence in its favour." 
 
 It is simply in the interest of Sanitary Science that I publish this 
 extract, and refer my readers to the evidence of Mr. Harpur which I 
 have previously given as a footnote. 
 
 2. KENDAL, WESTMORELAND. 
 
 At Kendal, the Council of the borough running in the opposite 
 course to that followed by the Local Board of Merthyr Tydfil instead of 
 preparing a large farm for surface irrigation, as they had been advised to 
 
58 
 
 Mode of 
 disposal. 
 
 Quantity of 
 land recom- 
 mended. 
 
 Quantity 
 actually pre- 
 pared and 
 used for fil- 
 tration. 
 
 Results. 
 
 do, determined to cleanse their sewage by intermittent filtration through 
 as small an area of land as possible. When the writer was called in by the 
 Council in 1873, he found the population to be about 13,500, the number 
 of houses 2,700 (having about 450 water-closets) the water supply about 
 400,000 gallons a day, and the quantity of sewage diluted with subsoil 
 water (exclusive of surface waters) varying from 750,000 gallons to 
 1,800,000 gallons daily, the mean dry weather discharge being 975,000 
 gallons daily. In wet weather the outflow from the sewers reached 
 5,000,000 gallons in 24 hours. With these details before him he 
 recommended the use by Intermittent Downward Filtration of 16 acres of 
 " suitably constituted soil" which had already been purchased by the 
 borough, and could be reached by gravitation, and which was capable of 
 underdrainage to the full depth of seven feet. The writer did so in con- 
 sonance with the view he had already adopted at Merthyr, i.e., that in 
 order to secure permanency of effect it would be well to limit the sewage 
 of 1,000 persons to an acre. The Council, bearing in mind the report 
 of the Rivers Pollution Commissioners that the sewage of 3,300 persons 
 might be cleansed by Intermittent Filtration through an acre of land, 
 however, rejected his advice and determined to limit the area to be 
 utilised to one-third of the 16 acres, and for seven years five and a half 
 acres of land have served, though not very perfectly, the purpose. As if to 
 reduce as much as possible the capability of so small an area to do such 
 an extreme duty, the Council took the earliest opportunity of letting the 
 land to a tenant who naturally considered the production of crops of 
 primary importance. The result of limiting the area in the way 
 mentioned and of letting the land to a tenant, who naturally regulates his 
 management by self-interest, is that the intermittent rest which all land 
 should have to prevent nuisance arising from the collection of solid 
 matter upon the surface has been withheld. Nevertheless, Mr. Banks, 
 the local Surveyor of the borough, wrote as recently as September 8th, 
 1880 (after seven years' trial), that — • 
 
 " The land at present is as you left it in regard to area, except that the 
 lower part of the field in which the filtration areas were formed has 
 been levelled, and for the last two or three years has been used as rye 
 grass plots, taking of course three or four times the sewage it formerly 
 did. By such use of the 11 acres outside the areas, the latter have been 
 relieved to the extent of one-fifth of the sewage." 
 
 Mr. Banks confirms in 1880 the views expressed by me in 1873 
 
 when he stated that — 
 
 " This outside land can be used as filtration areas with very little 
 
59 
 
 expense, and if I can prevail upon the Corporation to keep it in their 
 own hands we should free the areas for a year, and afterwards work the 
 whole together. As far as the purification is concerned it is perfect, and 
 I am convinced that with the 15 acres we have" (16 acres), "we shall 
 always be able to deal successfully with the sewage as far as the purity 
 of effluent and absence of nuisance is concerned. It was a great 
 mistake to let the land ; no farmer can make any profit where you have 
 such an enormous volume to deal with on such a small area of land. 
 The tenant has not been applying the sewage intermittently, but running 
 it on to the beds for days at a time, he only works it so as to make 
 his crops pay if he can, never caring if the land becomes less capable of 
 allowing the sewage to pass through it or not. Looking at the whole 
 scheme I think it has worked even more favourably than you expected." 
 
 It need hardly be said that although the required purification is so 
 completely secured, and has incontestably proved the soundness of Dr. 
 Frankland's views and the practice I founded upon them, it will not 
 be until the additional 11 acres are properly laid out and used, as 
 Mr. Banks says, in connection with the five and a half acres already 
 prepared, that the treatment of the land at Kendal can be offered as an 
 example to be copied by other authorities. 
 
 Owing to the River Kent forming the boundary of the sewaged land 
 on three of its sides, and the land being very porous, the discharge from 
 the underdrains is not constant, and therefore no analysis is given. 
 When the river is low the effluent finds its way through the subsoil 
 into the river itself independently of the underdrains. The advantage 
 derived from the underdrainage is to be found in the fact that the level 
 of the water in the land is maintained at a level no higher than that of 
 the water in the river under all meteorological conditions. Supersatu- 
 ration, that might occur in times of continued rainfall, is thereby 
 avoided. 
 
 It was with respect to the works at Kendal that the committee Report of 
 appointed by the President to the Local Government Board (December, RawUnson 
 1876) went out of its way to represent the cost of Intermittent Filtration and Read, 
 on the ratepayers of Kendal to be i,d. in the pound ; and to compare 
 it with the cost at Banbury and Bedford where Surface Irrigation has 
 been adopted and which they showed to be \d. in the pound ! At 
 Rugby they stated the cost to be -i.\d. in the pound ! Such comparisons 
 made in an official report must have had the effect on its readers of 
 disparaging the results at Kendal while exalting those of the three 
 other places referred to. In that Report the cost of the Kendal 
 "Sewage Farm" is stated to have been ^16,371, and the cost of 
 laying out the filter beds ;^i,4oo ; the charge of 4^. in the pound being 
 
statements. 
 
 60 
 
 based on these figures. Now, what are the real facts? The land 
 for which the ;^i6,37i was paid consists of 66 acres in the immediate 
 Inaccurate vicinity of the borough, and was bought by the Council at a price of 
 ;:f 248 per acre. Fifty acres out of the 66 acres lying above the main 
 sewer outlet, and costing upwards of ^^13,000 out of the ;^i6,37i, have 
 never for a single day been used for sewage purposes. If, instead of 
 charging the cost of the whole of the 66 acres against the disposal of the 
 sewage the proportionate amount paid for the 16 acres which alone 
 received the sewage had been made the basis of calculation the result 
 would have been \\d. in the pound instead of 4//. 
 
 Turning to the facts relating to Banbury, Bedford, and Rugby, we 
 find that no land whatever^ has been purchased in either case, but the 
 land utilised has been leased at very moderate rents, viz. : — at Banbury, 
 130 acres has been obtained for less than ^^5 an acre = £,(122 a 
 year; at Bedford, 181 acres at ;^5 an acre = ;^9i7 a year; and at 
 Rugby, 57 acres at ^6 loj. = ^£^360 a-year. By reference to Messrs. 
 Rawlinson and Read's report it will be seen that Banbury, Bedford, 
 and Rugby are only charged with these rents, while at Kendal it is 
 made to appear that "the Sewage Farm" of 16 acres has cost the 
 borough ;£iT,t6i, including its preparation ! 
 
 In the same report it is stated that the cost of preparing the five 
 acres and a-half laid out by me at Kendal for Intermittent Filtration 
 was ";^28o an acre." Here again I may fairly ask, what were the 
 facts? The sum of ^^ 1,400 was laid out not in preparing the five and 
 a-half acres only,* but in paying for an expensive conduit for the 
 delivery of the sewage to the whole of the 16 acres, and for the partial 
 underdrainage of the outside 1 1 acres as well. An acreage calculation 
 was therefore altogether inappropriate, inasmuch as the eifect on the 
 ratepayers of reducing the area of application is not to be measured 
 by the cost per acre of the works executed on the 5^ acres, but by the 
 ioial outlay, and the rateable contribution of the inhabitants towards its 
 repayment. At Kendal the current outlay in distributing the sewage 
 and in managing the sewaged land is more than met by the produce ; 
 the return for which in the shape of rent or profitf goes in reduction of 
 the charge for land and preparation. 
 
 * See descriptions of works given in the "Transactions " of the Institution, C.E., 
 Vols, xlviii, p. 205, and xlix, p. 197, 
 
 t As an earnest believer in the benefit to be gained by the country at large by an 
 accurate statement of facts relating to land filtration, I protest against the injurious 
 influence of such official misstatements as are here exemplified. 
 
6i 
 
 As a proof of the prejudicial influence of official misstatements it Official 
 may be pointed out that in a publication entitled "Water Carried ^n^ation 
 Sewage,'' intended '■'■for the guidance of Corporations, Boards of of facts. 
 Health and Sanitary Authorities" the authors, Messrs. Robinson and 
 Melliss, basing their statement chiefly on this report, declare circum- 
 stantially — 
 
 "That the farm to which the sewage of Kendal flows by gravitation 
 is 65 acres in extent ; of a sandy loam upon a gravel bed. Eleven 
 acres of this are used for Irrigation ; five for Filtering Beds ; and the 
 remaining 49 acres are used for the disposal of the solid matter and 
 sediment from the Tank. The amount paid for the land was ;^i6,37i 
 14.S ^d., or about ;^2S2 an acre." 
 
 Upon these data Messrs. Robinson and Melliss point out that the 
 charge on the population is ii^d. per head. They add that which the 
 opponents of Land Filtration will do well to study : 
 
 " The filtration areas are cultivated and the average annual working 
 expenses during the years 1874 and 1875 have been ;^223, and the 
 average annual return by sale of produce during the same periods have 
 amounted to ^^512." 
 
 The facts in relation to the land, as already shown, are the very 
 reverse of what is here declared ; the only land that is commanded 
 by gravitation consists of 16 acres out of the 66 acres. No sewage 
 touches the remaining 50 acres, and it is no more correct to charge 
 as expenditure on Sewage disposal the cost of the 50 acres not utilised, 
 than it would be to charge one district with the outlay made on 
 another. If, instead of utilising for filtration only 5 acres as here 
 stated, the whole of the i6 acres were laid out for that purpose, no 
 interception of the solid floating matter by tanks would be required. 
 The same 16 acres that would cleanse the liquid might beneficially 
 receive the floating matter. The only substantial objection I have 
 yet heard made to the Kendal works has been that raised to the 
 emptying of the Tanks which existed before the filtration areas were 
 made. This emptying takes place probably twice a year, which would 
 not be necessary if the screening operations were confined to 
 the removal of the coarser and heavier constituents only, and the 
 remainder was allowed to flow to the land, and there dug or 
 ploughed in. 
 
62 
 
 Mode of 
 Disposal. 
 
 Population, 
 6,000. 
 
 Extent of 
 Land pur- ] 
 chased, 48 ;; 
 acres (34 acres : 
 only sewaged). 
 
 Daily Outflow 
 of Sewage, 
 diluted with 
 subsoil water, 
 absorbed by 
 ij acre. 
 
 3. ABINGDON, BERKSHIRE. 
 
 At Abingdon, where the soil is very open and porous, the sewage 
 is cleansed by Surface Irrigation in combination with Intermittent Fil- 
 tration in the proportion of four acres of the former to one of the 
 latter. The works have been completed four years. 
 
 The population of the Borough is close upon 6,000, and the 
 quantity of sewage discharged daily approximates to 200,000 gallons in 
 dry weather, increased to double that quantity in wet weather, the 
 excess being due to the fact that the private sewers communicating with 
 the public sewers in the town receive the rain run oif the back roofs and 
 impervious surfaces connected with the houses. The number of acres 
 constituting the farm is 48 acres, of which 27^ acres were actually 
 laid out for Surface Irrigation, whilst the quantity devoted to Filtration 
 was 6^ acres, but the ground is so extremely porous that the filtration areas 
 are only resorted to when from some special reason the tenant finds that 
 the sewage cannot be advantageously applied to any other part of the 
 farm.* The capability of " getting rid " of the sewage on the filtration 
 areas when it is not wanted on the irrigation land is, however, such an 
 advantage that the Council of the Borough have been enabled 
 to let the land, with the sewage, at ^4 10s. an acre, its agricultural 
 value as ordinary farming''land being about half that amount. Instead 
 of finding the sewage too much for the land, the tenant has applied 
 to the Council to allow him to discontinue the application of sewage 
 to about eight acres out of the 27^ acres devoted to Surface Irrigation 
 which he proposes to lay down to permanent pasture. The land 
 laid out for filtration is divided into five beds containing nearly 
 an acre and a quarter each, and such is the absorptive powers of 
 the soil that the 200,000 gallons forming the daily outflow has been 
 applied to one area only for several weeks together, without overfilling 
 
 * It is to be regretted that the tenant does not maintain more perfectly than he 
 does the furrows of the filtration areas, and use them in the way intended, for he 
 suffers from the injury done to his growing crops by " flooding " his other lands and 
 by the accumulation of solid matters on their surface. 
 
63 
 
 the furrows. A deputation from Salisbury, indeed, paid a visit to the 
 
 farm in May last (1880) and reported that — 
 
 " Half an acre will take the day's sewage, and seven acres of rye 
 grass will take the sewage during the summer." 
 
 ( — a fact which may be readily abused if intermittency is neglected). 
 
 Experience at Abingdon indeed has incontrovertibly shown that, with 
 the most favourable soils, the liquid refuse of 3,300 people may be dealt 
 with successfully on a single acre as suggested by Dr. Frankland, the 
 only condition essential to success being that intermittency of application 
 shall be adopted. 
 
 The effluent from the sewaged land of Abingdon, which is mixed Effluent. 
 with a good deal of subsoil water, having been analysed by Doctors 
 Tidy and Woodforde, and by Professor Attfield, has been declared 
 " equal in purity to some waters used for drinking.'' The quantity of 
 albuminoid matter (yielding 10 per cent, of nitrogen) was found by the 
 last-named chemist to be "07 of a grain in a.gallon and the ammoniacal 
 matter (yielding 10 per cent, of nitrogen) "02 of a grain in the same 
 quantity. See Standards previously given. 
 
 The absence of smell from the surface of the land is so perfect Absence of 
 that, although a public footpath runs directly through the farm, the 1^^. °" 
 Town Clerk, Mr. Bromley Challoner, wrote me very recently (after 
 three years' experience) that " no complaint whatever of nuisance has 
 ever been heard." 
 
 The cost of preparing the land for Irrigation has been a trifle over Cost of pre- 
 jC^^o an acre, whilst that of preparing the filtration areas has been ;^85 P^'^^t'°° P^"^ 
 an acre. These figures include the delivering conduits, carriers, cham- 
 bers, roads, iron fencing, quick fencing, and other incidental expenses, as 
 well as engineering charges, and should be compared with the " reported " 
 outlay at Merthyr and Kendal. The total outlay in preparing the 34 
 acres of land to receive the sewage, and in the building of a farmstead 
 and cottage for Bailiff, has amounted to ^^3,470, making with the cost 
 of the land (48 acres in the whole) a total outlay of ;!£"io,64o. The 
 farm (48 acres) being let on lease for ;^2 25 a year, yields an income Income from 
 equal to 2\ per cent, on the cost of land and preparation, which goes in '^^^ ^""^ 
 
 reduction of the district rate ; and all expense in distribution is saved to2|^per 
 » ii. Tj u cent, on total 
 
 to the Borough. outlay. 
 
 It will be observed that, as the preparation of the land, including the 
 
 erection of cottage and farm buildings, costs ^£^3,470, the total acreage 
 
 outlay only just exceeded ;£i02 an acre, which is not half the 
 
64 
 
 amount stated to have been laid out at Merthyr Tydfil and Kendal, 
 without any buildings whatever ! 
 Sludge. At Abingdon there is no separation of the " sludge " from the 
 
 liquid before it is applied to the land for purification. Whatever passes 
 the screens, and is raised by the pumps, is distributed over the surface 
 by contour grips when the sewage is used for irrigation, or by the furrows 
 when it is used for filtration, and no difficulty whatever is experienced 
 in either case, nor is any smell perceptible at a distance of 20 yards. So 
 far from any difficulty or objection having been experienced from the 
 retention of the " sludge " in the sewage, the tenant has complained 
 that he has not sludge enough, and that the liquid is absorbed by the 
 land too quickly. Two hours after the cessation of pumping, no sewage 
 liquid is to be seen on the farm. 
 
 It has been observed in this case — as it has also been in the cases 
 of Merthyr and Kendal — that the soil utilised is exceptionally free and 
 percolative. This, however, is not the case, for in nine cases out of ten 
 the same rapidity of absorption, and the same results as to quality of 
 effluent, have atteaded the operations. It would be difficult to find 
 in England a parallel instance where the rent obtained for land and 
 sewage has been equivalent to 2^ per cent, on the total cost of land 
 and its preparation. 
 
 Population 
 12,500. 
 
 Mode of dis- 
 posal. 
 
 Quantity of 
 Sewage. 
 
 4. FORFAR, SCOTLAND. 
 
 This Burgh is the principal town of the County of Forfar in Scotland. 
 It has a population of about 12,500. The mode of disposing of its 
 sewage is that of Intermittent Filtration combined with Surface Irriga- 
 tion in the proportion of one acre to three. It was the first operation 
 of its kind in Scotland. Previous to the adoption of this treatment the 
 sewage flowed into the Loch of Forfar, the property of the Earl of 
 Strathmore, who, to protect his Estate from injury by the pollution of 
 the Loch, took proceedings through the Court of Session and com- 
 pelled the Sanitary Authority (the Commissioners of the Police) to adopt 
 a means of cleansing its sewage. The quantity of sewage discharged 
 in dry weather, varied from 400,000 to 600,000 gallons daily. 
 
 In 1877, Mr. Willet, C.E., of Aberdeen, was employed to effect 
 the sewerage of the town, whilst Messrs. Bailey-Denton and Co., of 
 Whitehall Place, London, were called in to advise as to the disposal of 
 the sewage,— which resulted in the adoption of the treatment men- 
 
65 
 
 tioned. The Commissioners purchased for the purpose, at a cost, with Extent of land 
 
 purchased, 
 expenses, of ;£^4,ooo, " Orchard Bank Farm,'' contaming about 40 40 acres. 
 
 acres of land adjacent to other property belonging to the Burgh, which 
 
 may ultimately, if required, be utilised for sewage purification. 
 
 The disposal works were executed in 1878 and 1879, at a cost of 
 
 ;£'i,45o, or ^60 an acre, and when accepted from the hands of the 
 
 engineers, were described in the local paper in the following terms : — 
 
 " The quantity of land prepared at Forfar to receive and cleanse Acreage 
 the present sewage is confined to about 24 acres only out of the 40 acres, Sewaged, 
 and the mode of treatment adopted is Intermittent Downward Filtration, ^4 °"' °' '^^ 
 combined with Surface Irrigation. The area of land devoted to Inter- '^° ^"^^" 
 mittent Filtration is seven acres, leaving 1 7 acres for Surface Irrigation. 
 The soil is of a free and open character, sandy and gravelly in parts, 
 though occasionally partaking of a somewhat loamy character. The 
 land may be described as admirably suited for the filtration of sewage, 
 but in order to avoid all chance of supersaturation, a main underdrain, 
 with subordinate drains, has been laid, which will keep down the sub- 
 soil water, and secure aeration, and so allow of perfect percolation of 
 the liquid distributed over the surface of the ground. 
 
 " The filtration areas are laid out in a series of terraces, each terrace 
 being on a perfect level, to be intersected by main furrows traversing 
 their whole length, with branch furrows cut at right angles to the main 
 ones. The main furrows are deeper than the branch furrows, in order 
 that they may receive the solid matter floating in the sewage, which will 
 deposit itself in them, and allow the liquid to be distributed by the 
 branch furrows evenly through the soil. The intermediate ground 
 between furrow and furrow is planted with vegetables, the roots of which 
 help themselves to what they require of the sewage, and will yield 
 abundant crops. 
 
 " The terraces forming the filtration areas, and the delivery of the 
 sewage to them, are so arranged that each terrace can receive its 
 quantum of sewage separately from the rest, or two or three can be 
 served at the same time according to the quantity of sewage to be dis- 
 posed of. After they have received 'their fill,' the sewage will be 
 turned on to other terraces, which in their turn will receive their quantum. 
 By this means that intermittency of application and consequent aeration, 
 upon which the oxidation of the putrescible ingredients of sewage 
 depends, will be effected. 
 
 " The fields laid out for wide irrigation are prepared very differently 
 from the filtration areas, inasmuch as the sewage is distributed over 
 them on the 'catch water' system, without any great alteration of 
 surface configuration. The distributing carriers follow the natural 
 contour of the land. When filled the sewage overflows their edge and 
 runs down the natural slope of the land towards the next carrier, which 
 is again filled to overflowing. The whole will be under the charge of 
 the 'waterman,' who controls and distributes the sewage in suitable 
 quantities by means of ' stops,' which he places in the carriers when 
 required to check the flow." 
 
66 
 
 Crops and 
 return. 
 
 The land was partially sown and planted in the year 1879. After 
 more than 1 2 months' experience the convener of the Water and Sewage 
 Committee, Mr. Whyte (now Provost), i.e., on the i8th day of October, 
 1880, reported to the Police Commissioners that from the experience they 
 had gained it was evident that the Sewage Farm would not only pay itself, 
 but perhaps the charge for the pumping station besides. In support 
 of this he laid before them the following tabulated statement of the 
 year's produce : — 
 
 Sev/aged Land. 
 East Field — Rye Grass. 
 
 Crop No. I — 21 tons 14J cwts. 
 
 2 — 26 
 
 }} 
 
 Si 
 
 )» 
 
 3—34 
 
 JJ 
 
 7i 
 
 )» 
 
 4—34 
 
 3) 
 
 3, 
 
 )j 
 
 5— 9 
 
 JJ 
 
 si 
 
 )j 
 
 5 acres 6 poles, 125 tons isf cwts., 
 or ;^i9 I'^s. i^d. per acre. 
 
 West Field— Rye Grass. 
 
 Crop No. 
 
 I — 21 tons i2| cwts 
 
 )j j» 
 
 2—28 „ 14I „ 
 
 jj )> 
 
 3—34 ,, 19 .- 
 
 >! » 
 
 4—25 » 9i ,. 
 
 S^ acres, no tons 15! cwts., 
 or ;^i6 135. td. per acre. 
 
 Filtration Areas. 
 
 Per Acre. tons. cwt. lbs. 
 
 Crop No. I — Cabbages ,.. 10 3 4 
 
 „ „ 2 — Carrots ... 55 6 8 
 
 „ „ 3— Turnips ... 12 13 o 
 
 „ „ 4 — Mangolds -.21 o o 
 
 „ „ 5— Swedes ... 13 6 9 
 
 £ 
 
 s. 
 
 d. 
 
 20 
 
 S 
 
 4 
 
 19 
 26 
 
 13 
 12 
 
 4i 
 8 
 
 25 
 
 6 
 
 12 
 19 
 
 3 
 4 
 
 19 7 
 24 14 
 29 o 
 19 2 
 
 ;^99 2 9 
 
 92 4 4 
 
 13 3 " 
 29 2 9 
 6 12 10 
 43 17 10 
 18 S 9 
 
 Cz/!/tfr Lands Sewaged, &=(. 
 
 2f acres of turnips, ;^8 per acre ... ... 22 2 11 
 
 Potatoes, 5 tons Myall's Kidneys, -^4 per 
 
 ton ... ... ... ,,, ... ... 20 o o 
 
 Carried forward 42 2 11 302 10 2 
 
£ 
 
 .f. 
 
 d. 
 
 £ 
 
 .f. 
 
 (/. 
 
 42 
 
 2 
 
 II 
 
 302 
 
 10 
 
 2 
 
 •■ 15 
 
 
 
 
 
 
 
 
 •• 30 
 
 
 
 
 
 
 
 
 2 
 
 10 
 
 
 
 89 
 
 12 
 
 
 
 
 
 II 
 
 .. 30 
 
 
 
 
 
 
 
 
 .. 2b 
 
 2 
 
 7 
 
 so 
 
 2 
 
 
 
 
 I 
 
 7 
 
 ... 
 
 442 
 
 5 
 
 8 
 
 67 
 
 Brought forward 
 Potatoes, 5 tons Regents and Champions, 
 
 £z 
 
 Savoys — say i^, £20 
 Barley, 2 qrs , 259. 
 
 Rent — Mr. Mount, Farm House, &c. 
 Rent — Mr. Graham, Land not sewaged 
 
 Total receipts from Farm 
 
 Mr. Whyte, continuing, said " they might reasonably look forward to 
 even better results from the filtration areas. Coming to the debit side 
 he took the cost of Orchard Bank and the expenses, ;^4,ooo, at 4 per 
 cent. — and £^60 was the rent of the farm. The expenditure for laying 
 out the farm amounted to ;^i,45o, to which some little additional expense 
 had had to be added, and he put the total at ;£^i,5oo, or at 4 per cent., 
 £()o. All the expense of working did not apply to the crop, but he 
 had put down ;^i5o, which he believed would cover the expense. 
 There was then a total of ^^370 as the cost of the farm. There was 
 thus a balance oi ^'^2 5^. Zd. in favour of the farm on the season." 
 
 At the same meeting the Commissioners came -to the following 
 resolution, which was signed by the Provost of the Burgh and forwarded 
 to the Engineers : — 
 
 Forfar Sewage Disposal. 
 
 "After the experience we have now had of the sewaged land at Preparation 
 Orchard Bank, we have pleasure in expressing our entire satisfaction '^°^' -^^° P^"^ 
 with the manner in which you have designed and carried out the works Road™'^ ^'^'"^ 
 for the disposal and cleansing of the sewage of this Burgh. With Fencing, &c. 
 respect to the actual cost of the works we find that you have prepared 
 seven acres for Intermittent Filtration, and 17 acres of hilly land for 
 Surface Irrigation, and have distributed the sewage over the whole by 
 glazed stoneware and iron pipes connected with chambers of masonry 
 for the sum of ;^i,45o. This amount includes the wages of Mr. Jonas 
 Harris, the Clerk of Works, for more than a year, during which time he 
 has attended not only to the cultivation of the farm, in addition to the 
 work of preparation, but to sundry matters connected with the sewerage 
 of the Burgh. It also includes the construction of roads, the alteration 
 of fences, the purchase of weighing machine, and the payment for seeds 
 for land, as well as other acts of husbandry. The filtration areas are 
 capable of absorbing and cleansing the whole of the sewage of the 
 Burgh when it is not distributed over the land laid out for Surface 
 Irrigation. Vegetable crops of considerable weight are grown on the 
 
 E 2 
 
68 
 
 former, while rye grass occupies the latter, and a fair return is to be antici- 
 Effluent. pated. The effluent is always most satisfactory. 
 
 " Passed at a meeting of the Local Authority of the Burgh of Forfar, 
 held on the i8th day of October, 1880, and signed for and on behalf of 
 the said Local Authority by me, 
 
 "JOHN LAWSON Junr., 
 
 " Provost." 
 
 These particulars so thoroughly confirm the views already expressed 
 that it is unnecessary to add any further explanation, but they may 
 serve to show that with a combination of the two treatments — Inter- 
 mittent Filtration and Surface Irrigation— not only may ratepayers be 
 relieved of loss in the disposal of sewage, but that a profit may be 
 gained after payment of interest on outlay, 
 
 Position and 
 Rainfall. 
 
 5. GREAT MALVERN, WORCESTERSHIRE. 
 
 Here Surface Irrigation had been in practice for some years before 
 the present treatment was adopted. Up to the year 1874 the sewage 
 was discharged from that portion of the district known as Great Malvern 
 on to land in the Pool Brook Valley, which was partly devoted to 
 permanent pasture, and partly to the growth of Italian Rye Grass, 
 without that careful preparation of the surface which is necessary if 
 sewage is to be absorbed by the soil and those abuses avoided which 
 are due to the overflow of sewage from the surface of the land into the 
 outfall streams. At Malvern the overflow was greatly increased by the 
 heavy and sudden downfalls of rain which characterise the locality. 
 
 The land upon which the sewage was treated in the way mentioned 
 was held by a tenant who found it impossible to avoid the collection of 
 fsecal matter in slacks and hollows of the surface and the washing off of 
 such solid substances into the brook on occasions of heavy rainfafl. The 
 consequence was that Sir Edmund Lechmere, Bart., M.P., living at the 
 Rhydd, on the banks of the Severn, at the junction of the Pool Brook 
 with that river, found that the off-flow from the sewaged land polluted 
 his water supply and brought down to his residence unmistakable signs 
 of sewage. On his representation of the facts the Local Board decided 
 to alter their mode of sewage disposal. 
 
 The town of Great Malvern stands upon the somewhat precipitous 
 
69 
 
 slopes of the hills known as the Malvern Hills, and the locality being 
 
 subject, as stated, to heavy falls of rain, a large quantity of water is 
 
 thrown off the surface, the greater part of which had been admitted into 
 
 the sewers to find its way by them to the sewaged land at the time 
 
 when Sir Edmund Lechmere's complaint was made. More than two 
 
 inches of rain have not unfrequently fallen in 24 hours, and as much 
 
 as 8,000,000 gallons have been thrown off the area covered by Great Water thrown 
 
 Malvern. °ff- 
 
 The Local Board having sought advice from the writer's firm 
 it was determined to separate, as far as practicable, the surface waters 
 from the sewage proper, and to exclude the former from the sewers. 
 It was further determined that in lieu of Surface Irrigation alone 
 as previously practised, the process of Intermittent Filtration in 
 combination with, and as a safety-valve to, Surface Irrigation should 
 be adopted, and that more pains than had hitherto been taken 
 should be taken to prepare the surface over which the sewage was 
 distributed in order that it might be absorbed rather than thrown off. 
 The work of separation, however, could not well be extended to the 
 whole of the surface tributary to Pool Brook. The proportion to 
 which a means of interception could be favourably applied was 
 limited to about two-thirds of the whole tributary area, or about 
 230 acres, — leaving rather more than one-third still discharging its 
 surface waters into the sewers. 
 
 By this separation at least 5,500,000 gallons of surface water have Quantity of 
 
 been removed from the sewers in times of storms, and the land now used ■^^'"f?'^^ intet- 
 
 cepted and 
 
 for the cleansing of the sewage has been relieved to that extent without excluded from 
 depriving the outfall stream of the district of its natural supply for 
 any length of its course. 
 
 The resident population contributing sewage to the sewers of this Population, 
 portion of Malvern was estimated in 1874 at 4,000, increased in 
 certain months constituting "the season," to about 6,000, but as 
 the popularity of the district as a place of health-resort is very 
 great it was necessary to make a large provision for the future disposal 
 of the sewage. 
 
 The present quantity of sewage proper measured by the water Present dry 
 supply amounts to 150,000 gallons a day, but in looking to the dilution ^^^"^^"^ °"'" 
 due to subsoil water which raises it to 350,000 gallons, and to the 
 future increase of population, it was considered desirable to provide 
 for four times the water supply, as the dry weather discharge, whilst it 
 
70 
 
 Quantity of 
 land utilised 
 in cleansing 
 40 acres. 
 How divided. 
 
 Character of 
 soil. 
 
 Intermittent 
 
 Filtration 
 
 areas. 
 
 Further land 
 can be 
 sewaged by 
 gravitation, if 
 hereafter 
 found desir- 
 able. 
 
 was assumed that in wet weather the discharge might exceed 2,000,000 
 gallons in 24 hours, after the separation referred to. 
 
 To provide for such discharges the Local Board purchased 40 acres 
 of land about a mile lower down the Pool Brook Valley than the land 
 which had hitherto been utilised, at a cost of;^7,ooo. Of this quantity 
 11^ acres have been laid out for Intermittent Filtration, 24 acres for 
 Surface Irrigation, and 2^ acres for the growth of Osiers, through which 
 to pass the surplus water (beyond that which the land is intended to 
 cleanse) in times of rainfall ; leaving the remainder (2 acres) to cover 
 the space taken up in roads, barrow paths, tanks, &c. The land is of 
 a mixed character on the New Red Sandstone formation, consisting of 
 marl and clay intermixed with a free rubbly earth or gravel, of a 
 sufficiently hard texture to supply the material for the roads on the 
 farm. The filtration areas are 11 in number, and together form a 
 square block in the centre of the 40 acres where the freest de- 
 scription of its soil exists, each area approximating one acre in extent ; 
 and such is the absorbent character of the soil now that it is thoroughly 
 drained that the whole of the present dry weather sewage (350,000 
 gallons) has been disposed of for several days in succession on a single 
 area only, and an effluent of a superior character obtained at the same 
 time. With this fact established and the power of applying the sewage 
 intermittently to any of the 1 1 areas it soon became manifest that the 
 quantity of land devoted to filtration would be of itself sufficient to 
 cleanse the sewage to be dealt with for many years to come. Having, 
 however, the command of 24 acres of Surface Irrigation, which wilL 
 take the sewage whenever it will be 'profitable so to apply it, the 
 Board will be made doubly secure ; and if it should be desired here- 
 after to concentrate sewage from other districts on the same land (as 
 has been done at Merthyr Tydfil) this object can be accomplished with 
 certainty also. 
 
 Beyond this combined arrangement there exists the capability of 
 applying the sewage to other land, outside the 40 acres, which exists at a 
 level to receive it by gravitation. The main delivering conduit, in fact, 
 has been laid at a height to command additional land if the Board 
 should determine either to increase the size of their sewage-farm, or to 
 sell the sewage for use on neighbouring farms. Moreover, the great 
 advantage of having filtering ground sufficient of itself to cleanse the 
 whole of the sewage will be experienced in the present case in the 
 capability of withholding sewage from the irrigation land whenever it 
 
71 
 
 is desired to grow cereal crops, hops, or any other plant or vegetable 
 which would better answer the purpose. 
 
 The cost of preparing the whole of the 40 acres for the reception of Cost of pre- 
 the sewage has not exceeded ;^3,3oo. This includes the underdrainage i^^^^ 
 and the surface formation of the whole, as well as the construction 
 of tanks, delivering conduits, and distributing chambers, the formation 
 of roads, and osier beds, iron fencing, entrance gates, osier planting, 
 the flushing arrangement of the underdrains, the charges of the Engineers, 
 and wages of Clerk of Works. The total cost of land and preparation 
 has not exceeded ;^io,ioo. 
 
 The difficulty of carting over land of which clay and marl are con- Roads, 
 stituents in winter and spring, when heavy loads of savoys and 
 other cabbages have to be removed to market, has rendered it neces- 
 sary to form roads of a somewhat expensive character. 
 
 A sample of the effluent from the underdrains was taken and Effluent. 
 
 submitted for analysis — after the sewage had been on one area for 
 
 several days, considering that such would be a very severe test of 
 
 the character of the effluent. The following is the analysis of Professor 
 
 Attfield :— 
 
 ^^ Analysis of ^Effluent from Great Malvern.^ 
 
 " 17, Bloomsbury Square, London, W.C, 
 
 "December i6tk, 1880. 
 
 " The appended data show that the amounts of impurities in this 
 effluent are well within official limits, and hence that it is admissible 
 into any ordinary river. 
 
 " The first of the following two columns of figures shows parts per 
 100,000, the second column parts per 70,000 parts (grains per gallon) 
 of the respective substances contained in the effluent. 
 
 
 Parts per 
 100,000 parts. 
 
 Parts per 
 
 70,000 parts 
 
 or grains per gal. 
 
 Total solid matter, dried at 212° F. 
 
 37-2 
 
 26- 
 
 Nitrogen (as ammoniacal matter) 
 
 ■33 
 
 ■23 
 
 Nitrogen (as organic matter) 
 
 •024 
 
 •017 
 
 Nitrogen (as nitrates, and much nitrites) ... 
 
 •24 
 
 ■16 
 
 Chlorine (as chlorides) 
 
 3-3 
 
 2-3 
 
 Temporary hardness (as chalk grains or 
 
 
 
 degrees) 
 
 II' 
 
 8- 
 
 Permanent hardness (as chalk grains or 
 
 
 
 degrees) 
 
 13- 
 
 9' 
 
 Total hardness (as chalk grains or degrees) 
 
 24- 
 
 17- 
 
 Lead or copper 
 
 none 
 
 none 
 
 ' The effluent is fairly clear and almost bright. 
 
 "(Signed) JOHN ATTFIELD." 
 
Storm water 
 osier bed. 
 
 72 
 
 It will be seen" by tlie accompanying map that Osier Beds for 
 the cleansing of such storm water as may be suddenly thrown down 
 on the farm in excess of the quantity the land will absorb, are situated 
 at the lowest margin of the land, next the outfall stream. They were 
 formed out of ground of uneven surface. The object of these Osier 
 Beds is not that of filtration through the soil, but simply to arrest 
 the solid matter floating in the storm water on its way to the outfall 
 stream, to effect which the osiers are planted on ridges in areas 
 formed on several levels, descending by steps to the outlet. By 
 this means the storm water passes from one level to another and 
 deposits such solid matter as it may contain in the furrows. 
 
 This example of Malvern is given to show that in a district where 
 it cannot be said that the conditions are in any way exceptional, 
 the combined treatment may be adopted with a certainty of success, 
 and at no unreasonable charge on the ratepayers. The farm is, at 
 present, in the hands of the Board, who intend to erect farm buildings 
 upon it for the housing of milch cows, pigs, &c. 
 
 Should the income after payment of current expenses of labour, 
 seeds, &c., reach ,^^5 an acre only, the return on the cost will be 
 ;^2 per cent. There is every reason to believe that as the distribution 
 is so arranged as to involve the least outlay in labour, the net income 
 will be much greater. 
 
 6, HALSTEAD, ESSEX. 
 
 Population The Urban District of Halstead has a population closely approach- 
 
 ,000. jj^g 6,000, and therefore resembles in that respect the condition 
 
 Mode of "-"^ Abingdon. The mode of disposing of its sewage is that of 
 
 Disposal. Intermittent Filtration combined with Surface Irrigation, and the use of 
 
 Osier Beds as a means of cleansing storm waters in times of heavy 
 rainfall when sudden excesses would overcharge the land, 
 from The daily dry-weather outflow from the town barely exceeds 
 70,000 gallons, but — although the sewerage was designed on what was 
 termed the separate system to exclude surface waters — the discharge from 
 the sewers in wet weather occasionally far exceeds 1,000,000 gallons in 
 the 24 hours. 
 
 Extent of The land to which the sewage is applied is of a mixed character, the 
 
 Outflow 
 
 Sewers. 
 
soil consisting of clay, gravel, and sand. The extent is iKi acres, of land utilised, 
 
 154 acres, 
 which rather more than 6 acres are devoted to Intermittent Filtration, 
 
 the same quantity to Surface Irrigation, and i^ acres to the growth of 
 
 Osiers. The remainder covers roads, banks, paths, and a spoil-bank to 
 
 be used for seed beds. 
 
 The sewage discharged from the town flows by gravitation to the Intermittent 
 
 ^, . , . , ^ . , , . ^ Filtration, 
 
 filtration areas, which are five in number, and vary m extent from an ,. j t. j 
 
 ' -^ Land reached 
 
 acre and a half to less than one acre. They are laid out perfectly level, by simple 
 
 at heights differing from one another according to the form of the 5 acres. ' 
 natural surface ; the highest area, as finished, being 4I feet above the 
 lowest. 
 
 The land laid out for Surface Irrigation occupies sloping ground Surface 
 
 rising gradually from the filtration areas, and a wind engine working a g aaes. 
 
 Noria has been erected to lift the sewage to the top of the slope, Wind used as 
 
 which is 20 feet above the invert of the sewer mouth. This engine i;ftin„ the ^ 
 
 necessarily only comes into action when the force of the wind is sewage for 
 
 ■ .1 , , Surface 
 
 sufficient to work it. Pains have been taken to make the most of the irrigation, 
 wind, and whenever it raises the sewage, or part of it, the filtration 
 areas are correspondingly relieved. With a fair wind the whole of the 
 sewage should be raised, and then the filtration areas will be freed from 
 the sewage altogether. It is calculated that for at least 100 days in 
 the year, the wind will relieve the areas of sewage, and if so it will be a 
 cheap motor. Its use will accord with that intermittency of appUcation 
 which is so essential to the purification of sewage, inasmuch as although 
 it will only be when the wind is sufficient to lift the sewage that the 
 filtration areas will be relieved, yet the aggregate number of days 
 when that power will be called into play being at least equal to one 
 day in four, a very material respite will be gained : — and such advan- 
 tage will occur precisely in that way which will most economically 
 conform to the process of Intermittent Filtration. 
 
 The use of wind for the raising of sewage to land* is a feature, 
 
 * In spite of the fickle character of this power it may also be found of value as a 
 motor in the supply of water to small communities wherever there exists a sufficient 
 quantity which can be lifted from a water-bearing stratum beneath, and stored in 
 reservoirs on the surface. It is seldom that a week passes at any time of the year 
 without a recurrence of sufficient wind to raise some, though it may be but a little, 
 quantity of water, and it is not too much to say that with an ample amount of storage, 
 many a village now dependent on polluted ponds and shallow wells might be supplied 
 with the best potable water at a comparatively small cost. 
 
74 
 
 Osier beds for 
 clarifying 
 storm waters. 
 
 Cost of the 
 preparation 
 of the land. 
 
 Cost of wind 
 engine and 
 tower. 
 
 Effluent 
 
 therefore, to which attention may be well given in all cases where a 
 part of the land to be utilised may be reached by gravitation, whilst 
 the remainder must be served, if reached at all, by pumping. 
 
 The Osier beds, intended to clarify storm waters, when they dilute 
 the sewage beyond the quantity which the land is intended to cleanse, 
 occupy a narrow strip of land running alongside the river from the lowest 
 filtration areas to the main outlet. These Beds are severally laid out 
 (see Map), as at Great Malvern, in levels, and so arranged that the 
 storm water, having passed through them consecutively and deposited 
 such solid matter as will be arrested in the furrows, will reach the outlet 
 into the river in a clarified state — the intention being to check, as far 
 as possible, by the successive levels, the onward rush of the water and 
 so encourage deposition in the furrows whenever the beds come into 
 use. 
 
 The delivery of the sewage to the filtration areas is so designed that 
 when the full quantity they are intended to purify is exceeded by sudden 
 storms the excess will pass onward to the river through the Osier Beds 
 instead of into the Colne direct. 
 
 From the experience already gained in the use of the combined 
 system here adopted, it would appear that the six acres of land devoted to 
 Intermittent Filtration might be found of themselves, if properly managed 
 with strict regard to intermittency of application and the maintenance of 
 the furrows at the different depths prescribed, sufficient to cleanse the 
 whole of the dry-weather outflow. Relieved, as the filtration areas 
 will be at times when the wind engine comes into action — equal in the 
 aggregate to one quarter of the year — all doubt of their constant and 
 future efficiency is removed. 
 
 The purchase and the preparation of the land, including the under- 
 drainage, the construction of screening tanks, delivering conduits, and 
 distributing chambers, embanking the land against river floods, fencing, 
 osier planting, road making, engineering, payment of the wages of the 
 Clerk of the Works, and other incidentals, has cost on the whole 
 _;^3,5oo. When giving this cost it should be stated that the earth 
 work in levelling the areas and osier ground has been very con- 
 siderable. 
 
 The outlay on the wind engine and tower, with well, pumps, &c., 
 has been ;£2 75, but this should not be charged to the disposal works, 
 but to the sewerage of the town. 
 
 A sample of the effluent taken from the underdrains before the 
 
75 
 
 ground was perfectly consolidated, and when it was considered to be 
 in its worst condition, and affording the severest test, was analysed 
 by Professor Attfield, F.R.S., and the following figures show in parts in 
 100,000 parts, the respective substances contained in the effluent : — 
 Total solid matter dried at 212° F. ... 63' 
 
 Nitrogen (as ammonia) ... ... ... "190 
 
 Nitrogen (as organic matter) ... ... '033 
 
 Nitrogen (as nitrites and nitrates) . . . -49 
 
 Chlorine (as chlorides) ... ... ... 9*4 
 
 At present, the land is in the hands of the Board. Should the 
 net income equal ;£$ an acre, the return to the ratepayers will be 
 ■£2 per cent, in the cost of land and its preparation. 
 
 Having supported the cases of Merthyr and Kendal by four cases 
 selected from my own practice taken from the north (Forfar), the south 
 (Abingdon), the east (Halstead), and the west (Malvern), where the 
 land operated upon has been of that character which would come within 
 the definition of " suitably constituted soil," I will now describe two 
 cases which, though successful, the soil utilised cannot be considered 
 equally suitable. 
 
 The four instances, from 3 to 6 inclusive, if fairly considered, will not 
 only have proved the soundness of Dr. Frankland's views and have 
 justified the works carried out at Merthyr Tydfil and Kendal, but will 
 satisfy engineers that these latter works, which have been so often de- 
 scribed as "exceptional," are in no way deserving that character, inas- 
 much as the four cases by which they have been here supported are 
 illustrations of what has been done in four of the widest surface for- 
 mations known to exist in the geology of Great Britain, viz. : the super- 
 ficial soils or drifted matter covering (1) the primary formations, (2) the 
 oolitic beds, (3) the London clay, and (4) the marl of the New Red 
 Sandstone. 
 
 7, BARNSLEY, YORKSHIRE, 
 
 The instance now about to be described — Barnsley — is one which character 
 will be interesting to many, because the land there utilised for Inter- °^^°'' utilised, 
 mittent Filtration would be commonly called "clay," consisting as it 
 
76 
 
 Population 
 25,000. 
 
 Number of 
 houses and 
 trades. 
 
 Quantity of 
 
 sewage 
 
 discliarged. 
 
 Land 
 
 purchased to 
 cleanse the 
 sewage. 
 How pre- 
 pared. 
 
 does of a loam, with a certain proportion of alumina in it, from the 
 whole of which bricks, pipes, and pottery have been made. 
 
 The population of Barnsley in 181 1 (70 years back) was 5,000. It 
 had increased from that time up to the time when the present mode 
 of sewage disposal was decided upon to 25,000. As Barnsley is a 
 manufacturing town it may be useful to state that the number of 
 houses at the present moment probably amounts to 5,000, and that 
 there exist in the Borough 25 factories, 8 collieries, besides Dye Works 
 and Bleach Works, several foundries, and a tannery. A considerable 
 quantity of trade refuse is discharged into the sewers. 
 
 The quantity of sewage in dry weather issuing from the sewers was 
 found, when gauged in 1874, preparatory to the works afterwards carried 
 out, to vary from 600,000 to 700,000 gallons per diem, whilst on occa- 
 sions of storms the quantity of water thrown off the impervious surfaces 
 of the town into the watercourses traversing it amounted to several 
 millions of gallons. 
 
 In devising the sewage disposal works it was considered that if 
 provision was made for the cleansing by Intermittent Filtration of 
 1,000,000 gallons as the dry weather outflow, increasing to 1,500,000 
 gallons in 30 years, it would be ample, assuming that steps were taken 
 to exclude, as far as practicable. Surface Waters from the sewers, and 
 that means were taken by overflows to discharge from the sewers into 
 the River Dearne those excesses which the land could not absorb in 
 times of heavy rainfall. 
 
 This design has been carried out, and the quantity of sewage 
 which has actually been delivered to the selected land in dry weather 
 has been found to amount to rather less than 700,000 gallons, whilst the 
 quantity which has passed the Storm Overflows in wet weather and 
 reached the land, has been found to approach 2,000,000 gallons in 
 24 hours 
 
 The land purchased by the Corporation amounted to 78 acres, for 
 which a very high price was paid, but as it was the only land that could be 
 reached by gravitation, some compensation for the high price was gained 
 by this advantage. Of the 78 acres, 30 were divided into 3 areas of 10 
 acres each, and laid out for Intermittent Filtration, — about 20 acres for 
 Surface Irrigation, and rather more than 2\ acres for the growth of 
 Osiers for cleansing those sudden excesses brought down to the farm, 
 but which the land would not absorb in times of rainfall. The remainder 
 of the property is made up of a water-mill and adjacent land. A'con- 
 
soil. 
 
 77 
 
 siderable portion of the last may be utilised for sewage cleansing here- 
 after, if and when necessary, and the motive power of the mill may 
 be applied to the lifting of a portion of the sewage to higher ground 
 should it be found desirable so to relieve the farm. 
 
 The sewage, as it is discharged from the town, passes through screen- Sludge, 
 ing tanks which arrest coarser and heavy matters only, and allow the 
 
 smaller particles to float on with the sewage to the land, where, after its 
 
 ,...,, How dispose 
 
 collection in the furrows prepared to receive it, it may be thrown out on of. 
 
 the surface of the ridged land and ploughed into the soil. When once 
 
 dry it assists in improving its percolative powers. 
 
 The soil was analysed by Dr. Voelcker at three different depths and Analysis of 
 
 was found to contain the following ingredients :— 
 
 "Analysis of the Soil used at Barnsley for Intermittent 
 
 Filtration 
 
 Analytical Laboratory, 
 
 II, Salisbury Square, Fleet Street, 
 November 26th, 1878. London, E.G. 
 
 Soils dried at 212° F. Marked — 
 A 
 Organic matter and water of combination 
 Oxide of Iron and Alumina 
 Carbonate of Lime 
 Magnesia and Alkalies, &c. 
 Insoluble Silicates and Sand 
 
 (Signed) AUGUSTUS VOELGKER." 
 
 After the sewage had been on the land, and the soil had been As to the 
 fully performing its filtering functions, a sample of it taken a foot ^le^s^ilf ° 
 below the surface was sent to the same eminent chemist, and he 
 reported that — 
 
 He "could not recognise any indication of clogging by sewage 
 matter," and added, " there is no excess of sewage matter, or, I should 
 rather say, there is no sewage matter, as such, in the two samples of 
 earth you sent me,— there is not a trace of offensive matter in either 
 sample." 
 
 In order to test the absorptive capability of the soil, a series of Exijerinienis 
 
 testing the 
 
 t 2 feet. 
 
 4 feet. 
 
 6 feet. 
 
 6-85 
 
 6*41 
 
 5-27 
 
 i3'3i 
 
 i3'36 
 
 13-10 
 
 1*29 
 
 •74 
 
 •44 
 
 I'OI 
 
 I '40 
 
 •95 
 
 77-54 
 
 78-09 
 
 80-24 
 
 1 00 '00 
 
 lOO'OO 
 
 loo-oo 
 
78 
 
 absorptive 
 powers of the 
 land. 
 
 Effluent 
 analysed. 
 
 Outlay. 
 
 experiments were made before the analysis last referred to was made r— 
 the quantity of sewage delivered to the land was gauged daily for ten 
 weeks and five days and a record kept of the extent of land to which 
 the sewage was applied daily. The result is shown on the accompanying 
 diagram, which distinguishes (i) the three different areas which received 
 the sewage during the whole period; (2) the quantity of sewage 
 discharged from the town each day ; (3) the number of acres receiving 
 it; and (4) the proportion absorbed per acre. Crops were growing 
 on the surface. At no time did the sewage overflow it. 
 
 The effluent water from the underdrains during the period of time 
 embraced by these experiments was analysed by both Professor Attfield, 
 F.R.S., and Dr. Meynott Tidy; the former found the proportion of 
 albumenoid organic matter yielding 10 per cent, of nitrogen to be '14 of 
 a grain in a gallon, and the latter "12 of one part in 100,000 parts. 
 
 By increasing the number of underdrains, so as more perfectly to 
 aerate the subsoil, the percolative powers of any land may be in- 
 creased; and these experiments have served to prove that with 
 additional drains in the filtration areas at Barnsley, a larger quantity 
 of sewage may be passed through them than at present; great care 
 being" necessary when applying sewage to effect even distribution and 
 to avoid, as far as possible, running it directly over the drains. 
 
 At Barnsley, where the soil, though clayey, is not dense, having 
 been found by analysis to contain in its natural condition about 80 per 
 cent, of insoluble silicates the sewaged land was rendered more porous 
 by mixing with the surface soil a large quantity of ashes made by 
 burning a proportion of it when the filtration areas were laid out and 
 levelled. It is therefore not so liable to crack when properly used 
 as many loamy soils. 
 
 The cost of preparing the 52^ acres of land laid out for Filtration, 
 Surface Irrigation, and Osier Beds, has been ^,^5,3 13 14^., including 
 drainage, service conduits, and distributing chambers, roads, embank- 
 ments, outfall cut, bridges, and incidental works. This sum covers 
 money spent in clearing the River Dearne, as well as the construction 
 of the screening tanks and the rebuilding of the Mill Weir. The out- 
 lay in incidental works, independent of the actual preparation of the 
 land, has, in fact, been almost as much as the land preparation itself. 
 
 The land is at present in the hands of the Board. 
 
 Since this treatise has been in the press, the following satisfactory 
 analysis of the effluent has been made by Professor Attfield : — 
 
79 
 
 " The first of the following two columns of figures shows parts per Effluent. 
 100,000 parts, the second column parts per 70,000 (grains per gallon) of 
 the respective substances contained in the effluent : — 
 
 Total solid matter, dried at 212° F. 
 
 Nitrogen (as ammoniacal matter) ... 
 
 Nitrogen (as organic matter) 
 
 Nitrogen (as nitrates — no nitrites) 
 
 Chlorine (as Chlorides) 
 
 Temporary hardness (as chalk — grains or 
 ' degrees') 
 
 Permanent hardness (as chalk — grains or 
 'degrees') .. 
 
 Total hardness (as chalk — grains or ' de- 
 grees ') 
 
 Lead or copper 
 
 Parts in 
 100,000 parts. 
 
 44' 
 
 •017 
 
 "012 
 •83 
 
 17- 
 23' 
 
 none 
 
 Parts in 70,000 
 
 parts (or grains per 
 
 gallon). 
 
 31" 
 •012 
 '008 
 ■58 
 2-8 
 
 4" 
 12' 
 
 i6- 
 
 none 
 
 " The effluent is inodorous and fairly clear — almost bright. 
 
 "(Signed) JOHN ATTFIELD." 
 
 8. HITCHIN, HERTFORDSHIRE. 
 
 This case, which was attended with several drawbacks, resulting from Local circum- 
 the character of the sewerage of the district as well as from the nature fg^'^f^ ' 
 of the land utilised, presents some important considerations, for it Hitchin. 
 shows that in spite of the difficulties experienced, an effluent admissible 
 into running streams may be secured with certainty from filtration 
 through peat of a boggy nature. 
 
 Hitchin is situated geologically at the base of the northern escarp- 
 ment of the London basin, — at the junction of the chalk with the Green- 
 sand formation. The River " Hiz " takes its rise in this escarpment, 
 and runs through the town. The land on each side of this river 
 consists for the most part of peat mixed, where shallow, with gravel, 
 sand and clunch, and the land selected for the cleansing of the sewage 
 was situated on its banks. The sewage flows by gravitation to this 
 land, which is about half-a-mile below the lower end of the town. 
 
 Hitchin was one of the earliest places sewered after the passing of 
 the Public Health Act, 1848, at a time when the ruling principles upon 
 
8o 
 
 Report as to 
 mode of 
 sewage dis- 
 posal, 1874. 
 
 Population 
 8,000. 
 
 Water supply. 
 
 Land required 
 for the cleans- 
 ing of the 
 sewage. 
 
 which sewerage works should be conducted were not as well under- 
 stood as now. The sewers of the whole town, consisting of glazed 
 socket pipes of various sizes, were jointed with clay, whilst the main 
 sewer, with no other sort of jointing, was laid for nearly the whole 
 distance through the town under the river itself. The surface waters 
 from roads, roofs, and paved surfaces were purposely admitted into the 
 sewers, for flushing, and as the ground upon which the town 
 stands was exceedingly wet, owing to the geological features to which 
 reference has been made, it only required "the pressure due to the 
 sudden influx of surface waters into the sewers to disturb the jointing, 
 and admit copiously the subsoil water. The streets and roads contri- 
 buting surface waters have rapid inclinations, and the sewers laid in 
 them necessarily partake of the same condition. The effect of this 
 state of things upon the outfall sewer was to cause rupture at its joints 
 and to admit water from the river into it. 
 
 In 1874, when the Local Board sought advice on the disposal of 
 the sewage, it was explained that this defective condition of the main 
 outfall sewer would be rectified by the substitution of a new sewer 
 following a course independent of the river. At the same time it was 
 understood that the rain falling on impervious surfaces within the town, 
 as well as other foreign waters (such as those from the public baths and 
 private springs), would be excluded from the sewers, leaving tributary 
 only such subsoil water as found its way into the branch sewers of the 
 town, and which could not practically be withdrawn. 
 
 The present population of the town is between 7,000 and 8,000, 
 and a somewhat rapid increase may be expected. 
 
 Exclusive of the water consumed in one important trade, that of a 
 fellmonger, who takes what he uses direct from the river, the general 
 supply of the town by public service and from private sources amounted 
 in 1874 to between 100,000 and 120,000 gallons a-day, and this con- 
 stituted then, as it does now, the " sewage proper " of the district. 
 
 It was with these considerations before him, and with a desire to 
 make ample provision for the future, that the writer recommended the 
 Local Board to acquire by purchase 30 acres of land, of which 27 acres 
 might be used for the disposal of the sewage, which, in dry weather, he 
 considered, might amount, with the subsoil water, to 175,000 gallons, 
 and be augmented by increased population to 350,000 gallons per day, at 
 the end of 30 years; in wet weather, the writer considered that the 
 outflow might fairly be taken at 500,000 gallons per day. Of the 
 
8i 
 
 27 acres, he proposed that 9 acres should be devoted to Intermittent 
 Filtration, and the rest to Surface Irrigation. The Local Board 
 rejected this advice, and determined not to prepare 30 acres, but to 
 restrict the quantity to be utilised to certain lands bounded by the 
 river, containing 2'2 acres, of which a portion which could not be 
 reached by gravitation formed a part, leaving only about 19 acres 
 available for use. And it is more than probable that if the expecta- 
 tions formed at the outset as to quantity of sewage and character of 
 soil could have been realised, this extent of land would have sufficed 
 for the cleansing of the sewage of Hitchin for thirty years to come. 
 
 The 22 acres of land cost, with legal expenses, nearly ^4,000. 
 
 It turned out, however, when the time came for executing the works, 
 that only two-thirds of the length of the main outfall sewer could be 
 replaced by another sewer independent of the river, without derange- 
 ments of a very serious character. It was therefore determined not to 
 fulfil this part of the undertaking, and the water which found its way 
 from the river into the remaining third of the length still remains to 
 dilute the sewage discharged on to the land. 
 
 The constant addition to the " sewage proper " from this source and Dry weather 
 from the subsoil in which the internal sewers of the town are laid augment 
 amounts to more than the whole of the water supply of the town, and, 
 therefore, to more than the "sewage proper" itself. The water ab- 
 stracted from the river and turned into the sewers by the Fellmonger, 
 under his legal rights, serves also to augment the outflow already 
 increased by the subsoil water. 
 
 The quantity of sewage, diluted with these subsoil and foreign waters, Actual outflow 
 which actually finds its way on to the sewaged land in dry weather varies sewers, 
 
 in some measure according to the season, but it is never less than 400,000 
 gallons in the 24 hours, which is 50,000 gallons more than the writer 
 anticipated when he recommended 30 acres as the quantity of land to 
 be provided for the disposal of the sewage 30 years hence. 
 
 When the removal of the surface waters from the sewers came to be 
 considered by the Board, it was found too that the work of separation 
 was so difficult that it could only be partially effected. The result has 
 been that so much tributary surface still remains to throw off the rainfall 
 into the sewers that if only a quarter of an inch falls on the town, the 
 outflow from the sewers is suddenly increased to an amount quite 
 equal to that of the sewage proper, and such is the rapidity with which 
 this extra discharge is delivered to the land, owing to the great fall 
 
 F 
 
82 
 
 Difficulties to 
 be contended 
 against. 
 
 Outlay. 
 
 Effluent 
 analysed. 
 
 the sewers possess, that no arrangement for distribution can meet the 
 difificulty. 
 
 While these facts were being discovered and the decision of the 
 Board to reduce the area of land from 30 acres to 22 acres was 
 being acted upon, it was found that the extent of boggy peat, a soil 
 which repeals, in a measure, percolation, formed a much larger proportion 
 of the land than previous examinations had led the writer to anticipate. 
 
 Thus, whilst the quantity of diluted sewage to be cleansed amounted 
 to more than it was expected would be the case 30 years hence, and it 
 was found that the larger part of the land consisted of soil which 
 could not be termed " suitably constituted," the total area utilised was 
 very considerably reduced by the decision of the Board. At no very 
 distant time, however, it may be assumed that the Board, following the 
 example of Kendal, will extend the sewaged land from the 22 acres 
 to the 30 acres originally recommended, and so bring into use eight 
 acres of land of a more suitable character, when the difficulties which 
 have now to be contended against will be completely overcome. 
 
 The total expenditure on the land, with screening tanks, roads, 
 and fencing, as well as the construction of a very expensive outfall 
 underdrain to take the effluent water under the river to the tail of a mill 
 below, has been ;^2,3oo, including all incidental expenses. For this 
 sum nearly the whole of the land has been laid out for Intermittent 
 Filtration, instead of nine acres only, as originally intended. 
 
 The land is let to the writer at ^£'55 per annum, and the charge on 
 the ratepayers is 3^. in the pound to repay cost of land and its 
 preparation.* 
 
 In spite of the difficulties that have been experienced in this case, 
 owing to the excessive dilution of sewage and the existence of so large 
 a proportion of peat in the land utilised, the effluent from the under- 
 drains having been analysed by several chemists of eminence, has 
 
 * Being a resident in the neighbourhood of Hitchin the writer holds this small 
 farm with a view of testing the capabilities of a peaty soil to cleanse sewage when sub- 
 jected to the extreme drawbacks of great dilution of sewage (by both subsoil and 
 surface waters) and a reduced area of land. The result in relation to the cleansing 
 of the sewage is given in the text. The capability of a soil consisting chiefly of a 
 boggy peat to yield heavy crops of roots and vegetables while acting as a filter is 
 proved by the facts that the gross returns amounted in 1879 to £z2S 9s. loo?., and 
 in 1880 are estimated at ;£'420. One of the disadvantages attending the use of peat is 
 that it must be cultivated by spade husbandry, and that the tenant's expenditure is 
 thereby increased. (December, 1880.) 
 

 been declared by them to be well within the standard suggested by the 
 Rivers Pollution Commissioners. Professor Attfield gave the following 
 results : — 
 
 "Analysis of Effluent Water taken, April ist, from Underdrain 
 from Soil which is principally Bog Peat : — 
 
 London, April ^th, 1878. 
 
 One gallon contains the following number of grains and decimal 
 parts of a grain of the respective substances : — 
 
 Total solid matter, dried at 212" F 40' 
 
 Ammoniacal matter yielding 10 per cent, of 
 
 nitrogen 0*45 
 
 ^ Albumenoid organic matter yielding 10 per 
 
 cent, of nitrogen ... ... ... ... o'03 
 
 Nitrites Traces. 
 
 Nitrates containing 17 per cent, of nitrogen ... 3-4 
 
 Chlorides, containing 60 per cent, of chlorine 4*2 
 
 "(Signed) JOHN ATTFIELD." 
 
 Professor Wanklyn gave the following results of an analysis made 
 by him of a sample taken without knowledge of the writer by the 
 Surveyor of the Croydon Local Board. The copy here printed was 
 politely supplied by order of the Croydon Board. 
 
 "ANALYTICAL REPORT. 
 
 Laboratory, 7, Westminster Chambers, S.W. 
 
 
 Sample of water, 'Effluent \ 
 water from the Sewage f 
 Farm at Hitchin,' sent by X 
 the Croydon Local Board ) 
 
 Grains per Gallon 
 
 Parts per Million 
 
 
 Solids. 
 
 Chlorine. 
 
 Free 
 Ammonia. 
 
 Albumenoid 
 Ammonia. 
 
 1879 
 
 8th 
 Oct. 
 
 36-3 
 
 3-3 
 
 5-00 
 
 i-oo 
 
 " This is not drinking water ; but it may be discharged into a stream. 
 "(Signed) J. ALFRED WANKLIN." 
 
 Having in the preceding Eight instances of Sewage Disposal shown 
 what has been done with " suitably constituted soils " and with those of 
 a less inviting character, the following cases are added to show what has 
 been done in smaller cases of varying character. 
 
 F 2 
 
 1878. 
 
 1879. 
 
84 
 
 Oakham, 
 3.0O0. 
 
 Mode of 
 disposal. 
 
 Cost and cur- 
 rent outlay. 
 
 Return. 
 
 General 
 Result. 
 
 9. OAKHAM, RUTLAND. 
 
 Oakham is the county town of Rutland, and has a population of 
 3,000. The town — which has been recently sewered by Mr. C. W. 
 Whittaker, C.E., of Great George Street, Westminster, is for the most 
 part, together with the land surrounding it, the property of Mr. G. H. 
 Finch, of Burley-on-the-Hill, M.P. for the county. In consideration of 
 the improvement the sewerage of the town would be to his estate, 
 Mr. Finch undertook at his own expense to dispose of the sewage 
 (though much diluted by subsoil water) on his own land. 
 
 Under the advice of the writer (given in 1878), the method of 
 disposal adopted was Intermittent Filtration through land, three acres 
 in extent, with Surface Irrigation over some adjacent land. The site 
 selected is on the marlstone of the lias formation. The rock of this 
 stratum here comes to the surface, and the cost of forming the land, 
 which has a rapid slope into level terraces, was, therefore, very con- 
 siderable. 
 
 Mr. Finch himself directs the mode of treating and cropping these 
 filtration beds, and employs to work them one man, whose wages amount to 
 ;^44 4.S. per annum. It has been found, after two years' use, that the whole 
 of the sewage of Oakham may be cleansed on the three acres of filtra- 
 tion ground, though it has been found advantageous to apply some of 
 the sewage in irrigating about five roods of land immediately below the 
 beds. 
 
 This year the money return from 2J acres of mangold and from 
 half an acre of cabbages grown on the filtration areas, and the five roods 
 of Rye Grass, has been ;^85 $s., leaving a balance, after payment of the 
 water-man's wages (^44 4s.), of ;^4i is. This pays Mr. Finch his rent 
 for the land and the current outlay in seeds, &c., as well as about 2^ 
 per cent, on his expenditure in preparation. If, at a future time, he 
 desires to extend the use of the sewage on his estate, he has it in his 
 power to do so at very little cost. 
 
 Mr. Finch, writing to the author (December ist, 1880), says :— 
 
 "The Oakham Beds work capitally, though they have occasionally 
 been overburdened with Storm Water during some of the heavy rains 
 
85 
 
 this summer. The analysis of the effluent last year was everything that 
 could be desired. The great point I had in view when I undertook the 
 construction of the Oakham Sewage Beds was the purification of the 
 sewage, and this object I seem thoroughly to have obtained." 
 
 l?;il5^!rR?.''} WARWICKSHIRE. 
 
 These two cases, Earlsdon and Radford, are bracketed together Populations, 
 because they are both Suburban Villages in the near neighbourhood of 
 Coventry. They contain present populations of i,ooo and 600 respec- 
 tively. The sewage is collected in each instance in a " Self-acting Sewage 
 Regulator" tank, discharging, when full, by means, in the one case Regulator 
 of a "syphon" and in the other of a "float outlet." The "Self-acting 
 Sewage Regulator" is an invention to discharge, automatically, the 
 quantity of sewage or other liquid which may be applied to land, either 
 for the purpose of utilization or purification. One of the most prominent 
 difficulties which presents itself in the utilization of sewage, is the very 
 different quantity which is discharged from sewers at different times. 
 In many towns and villages the flow will be diminished, at certain 
 periods, to a mere dribble ; while at other times there will be a copious 
 discharge. Hence, as it is essential to economy in sewage farming that 
 the crops should receive only that quantity of sewage which will 
 produce the most fruitful growth, and as it is equally essential to success 
 in Intermittent Filtration that the soil used to purify the sewage should 
 receive only the quantity which it is capable of purifying, it is very 
 desirable, as already pointed out, to have a means of regulating the 
 quantity of sewage to be dealt with. " The Self-acting Sewage Regu- 
 lator" performs this service in the most simple and perfect manner, 
 during the night, as well as during the day, and without any supervision. 
 The sewage is made to flow into a tank of such capacity that when the 
 liquid rises to a given level, the tank holds the precise quantity it is 
 desired to deliver to a certain area of land at one time. This tank is 
 provided with a syphon, or other self-acting outlet, which is brought 
 into action as soon as the liquid rises to the given level. When this is 
 reached, the liquid flows out of the tank ("automatically"), and con- 
 tinues flowing until the level of the liquid in the tank has fallen to its 
 lowest limit. The sewage flowing into the tank then fills it again, — 
 
86 
 
 Earlsdon, 
 
 population 
 
 i,ooo. 
 
 Acreage used. 
 
 Radford, 
 
 population 
 
 600. 
 
 slowly or quickly, according to the rate of influx, — and, as soon as it is 
 full, the automatic discharge will be repeated, and the liquid can be 
 applied either to the same area of land, or to another, as desired. 
 The coarser matters floating in the sewage are intercepted in a 
 separate chamber, called " the intercepting chamber," the finer particles 
 being carried forward with the liquid through the strainer into the tank. 
 If it be desired to eff'ect a precipitation of these finer particles, the 
 space in the Meter-tank below the mouth of the outlet is increased in 
 depth, so as to form a receptacle for any amount of deposit which 
 it may be determined to precipitate. In such case the space above 
 the mouth of the outlet will be occupied by clarified liquid, to be 
 discharged on to land automatically as already described, while the 
 space below will serve as a receptacle for the deposit, means, in some 
 cases, being provided by a duplicate tank for draining off the liquid, so 
 as to allow of the consolidation of the deposit for removal. These 
 Regulator Tanks are duplicated or not, according to the quantity of 
 sewage under treatment and the use to which the precipitated matter is 
 to be applied. Where the quantity of deposit is trifling, it can be 
 flushed out periodically without consolidation, and applied directly to 
 the land. 
 
 The quantity of land purchased by the Sanitary Authority for Earls- 
 don, which consists of clay of the New Red Sandstone intermixed with 
 sand and gravel, was 35 acres, of which rather less than 2 acres 
 were prepared for Intermittent Filtration, while the rest remains in 
 an unprepared condition for sewage appropriation as required. The 
 two acres have been in use for sewage cleansing since 1875, discharging 
 an effluent of a superior character during the whole of that time. 
 The whole of the land {i\ acres) is let for £,\o a year, and although 
 such a return in itself is insignificant the advantage is really con- 
 siderable, inasmuch as the tenant relieves the Local Authority from all 
 current outlay as well as all trouble in the matter. 
 
 In the case of Radford, Intermittent Filtration on a less area was 
 adopted by the same Authority in 1879, after the success at Earlsdon 
 had been assured. Here i\ acres were purchased, while if acres were 
 utilised for filtration. The land (2^ acres) is now let for ;^7 \as. a-year, 
 the tenant taking upon himself the distribution of the sewage. 
 
 In both instances the land utilised is not far from habitations, yet 
 no objection has been raised on the ground of nuisance. 
 
87 
 
 12. CONVALESCENT HOSPITAL, WALTON, SURREY. 
 
 This case is given as one showing what may be done unobjection- Convalescent 
 ably with sewage in the case of Public Institutions and Isolated ^^^ ^ ' 
 Dwellings. Here the land devoted to the cleansing of the sewage 
 daily discharged from the hospital forms the vegetable garden attached 
 to it. The number of inmates varies from 250 to 400 persons. The 
 disposal works were executed in 1869. 
 
 The tank in which the sewage is collected is discharged by means of 
 a sluice which the attendant raises in the evening or early morning once 
 in the 24 hours. The area of land devoted to the purpose of cleansing 
 is rather more than an acre, and although it immediately adjoins 
 the hospital and has been in use for more than 10 years, no nuisance 
 has at any time been experienced. It will be observed that this in- 
 stance of sewage treaament by filtration was executed before the pub- 
 lication of the Report of the Rivers Pollution Commissioners, in which 
 "intermittent downward filtration" was first suggested, and it is some- 
 what remarkable that the efHuent was analysed for the Managing 
 Committee of the Hospital by an eminent chemist and declared to be 
 excellent " potable water," which is in some measure to be explained 
 by the fact that the effluent when discharged is diluted by the subsoil 
 water drained out of the land. 
 
 Standing Rules to be observed when adopting 
 Intermittent Filtration. 
 
 Having selected from works designed and executed by the writer's 
 firm, a dozen cases of Intermittent Filtration, varying in size and 
 character, as illustrations of what may be done in different localities, 
 it may be well to state, in the order of their importance, the govern- 
 ing rules essential to the successful {i.e., profitabli) disposal of sewage 
 when recourse is had to land as the cleansing medium. 
 
 I. Foreign waters — subsoil water, surface water, and liquid trade 
 refuse — should be, as far as practicable, excluded from the sewers of 
 
88 
 
 all districts, inasmuch as it matters not what the precise treatment of 
 the sewage be — irrigation or filtration in combination or otherwise, — it 
 is certain that if the sewage proper be diluted to such an extent that 
 the modus operandi is at times deranged, failure or injury results. 
 
 2. The preparation and formation of land to receive sewage should 
 be effected with precision, and not in the careless way in which it 
 has been suggested sewage farms may be laid out. Irregular surfaces 
 and steep slopes should be avoided even more carefully than clay 
 soils, for all liquids will run down sloping surfaces and collect in 
 the lowest places, to the injury of crops and the creation of nuisance, 
 and the more sewage is diluted with foreign waters, the greater will be 
 these evils. There is no economy in carelessly executed land-pre- 
 parations, and it is greatly to be regretted that such views have been 
 inculcated. 
 
 3. Intermittency of application and regulation of quantity should 
 take the place of the haphazard distribution which prevails on most 
 sewage farms, for it is the want of these desiderata which brings dis- 
 credit to the engineer and loss to the farmer. With sewage intermit- 
 tently distributed in quantities apportioned to the extent of surface to 
 which it is applied, the best results are obtained. Intermittency of 
 application is positively essential to a continued good efHuent. Where 
 an inferior effluent from underdrains is found it is invariably due to 
 constant filtration through the same land. 
 
 When Intermittent Filtration areas are properly laid out on a 
 perfect level, and intersected by furrows dug at different depths, the 
 liquid sewage will convey to the land, where it is most wanted, those 
 floating solid particles which are not arrested by ordinary screening. 
 The furrows being designedly dug at different depths and in selected 
 positions, the deeper ones become the receptacles of the solid in- 
 gredients called " sludge," which having passed through the screens 
 deposits itself in them, while those at less depth serve to distribute 
 the liquid evenly through the soil. It will be found that by resting 
 the sewaged areas, one after another, as soon as this wet sludge has 
 accumulated in- the furrows, it will there solidify and dry, and may 
 then be removed and spread upon the land without any -difficulty 
 whatever. Being afterwards dug in it mixes with the soil and renders 
 it more percolative than before, and thus all necessity for separating the 
 solid from the liquid portion of sewage is avoided,— except possibly in 
 the case of certain trade refuse which may require special treatment. 
 
89 
 
 It is quite a mistake to suppose that land may be made too rich by 
 sewage where plant growth is regarded as one means of rendering the 
 soil a purifier. , 
 
 5. Where Intermittent Filtration areas form part of an irrigation 
 farm a sufficient proportion of the areas should be always ready to 
 receive the sewage when it cannot be beneficially applied to the 
 remainder, or to receive so much of it as may be in excess of what the 
 remainder will absorb with advantage. 
 
 6. The underdrainage of both Filtration areas and surface irri- 
 gated land should be laid out as carefully as practical science will 
 suggest so as to avoid drawing the liquid sewage down from the surface 
 
 ,to the drain without passing through the undisturbed ground on each 
 side of it. 
 
 7. Means should be taken in connection with the screening to 
 intercept road detritus as far as possible, as it will be apt to fill up 
 the furrows quickly. 
 
 To arrive at the actual cost of disposing of Town Sewage, by recourse Pumping 
 to land, or indeed by any means, it is necessary that the calculations ^la^ed in the 
 should be quite free of any outlay connected with the sewerage of the cost of the 
 
 Sewerage, and 
 
 district or with the liftmg or delivery of the sewage to the disposal not in that, of 
 
 -orks. Sewa.^^ <i- 
 
 The delivery of the sewage in some cases may involve pumping, 
 whilst in others the sewage may flow to the works by direct gravitation. 
 In the former instance, the cost of pumping forms a part of the cost of 
 the system of sewerage, and not of the disposal of the sewage. 
 
 Land Treatment compared with Chemical precipitation. 
 
 With the foregoing particulars recorded, it may answer a useful purpose 
 if the cost of the treatment by land is compared with that of chemical 
 precipitation in tanks, taking for the purpose those instances of the 
 latter mode of disposal as may be fairly put forth as examples of 
 well received processes. 
 
 I will compare Aylesbury, where the Native Guano Company have Aylesbury 
 relieved the Local Authority of treating the sewage of their district, and ^°^^^^^'^ 
 are exhibiting the ABC process (alum, blood, clay, and charcoal) in the Abingdon, 
 best form to recommend its adoption, with Abingdon, the mode of dis-. 
 
90 
 
 Hertford 
 compared 
 with 
 Halstead. 
 
 posing of the sewage of which has been described in these pages ; and 
 I will further compare Hertford, — where the Rivers Purification Company 
 (sulphate of alumina) occupy the same position in relation to the 
 Sanitary Authority of that borough as the Native Guano Company do 
 with the Local Board of Aylesbury, — with Halstead. The following 
 results are arrived at: — 
 
 
 Aylesbury. 
 
 Abingdon. 
 
 Hertford. 
 
 Halstead. 
 
 Population 
 
 7,200 
 
 6,000 
 
 7,250 
 
 6,000 
 
 Cost of tank arrangements 
 Cost of land and prepara- 
 tion 
 
 £ 
 7,265 
 
 £ 
 10,640 
 
 £ 
 3,3°o 
 
 £ 
 
 3,500 
 
 Interest on outlay 
 
 Add payment of subsidy to 
 the Companies after de- 
 ducting rent of premises 
 
 363 
 200 
 
 532 
 
 i6s 
 600 
 
 175 
 
 Total annual charge 
 Deduct rent or income 
 from land 
 
 563 
 
 532 
 225 
 
 765 
 
 175 
 
 so 
 
 Amount chargeable on the 
 rates of the districts 
 
 563 
 
 307 
 
 76s 
 
 125 
 
 From these figures it will be seen that in the two towns, Aylesbury 
 and Hertford, where tank arrangements are used, the annual charge on 
 the ratepayers is severally is. ^d. and 2s. \\d. per head, while in the 
 two towns, Abingdon and Halstead, where land treatment has been 
 adopted, the charge on the ratepayers is severally \s. o\d. and 5^. per 
 head of the populations. 
 
 The comparison of Aylesbury with Abingdon is one that cannot 
 be impeached on any ground of difference in conditions, though it is 
 possible that the outlay of ;^7,26s expended by the Local Board in 
 tank arrangements is m excess of what the Native Guano Company 
 would themselves have laid out for the prosecution of their own 
 process ; but against this proposition there stands the liability of the 
 Aylesbury authority to repay the Native Guano Company any sum 
 that they may have expended for their own purposes by valuation at 
 the end of their present lease. It may be assumed, therefore, that 
 so far as outlay in works or land goes, the relative figures represent 
 
91 
 
 fairly the facts in each case. On other grounds the cases demand 
 consideration. Should anything occur to lead to an abandonment of 
 the present works at Aylesbury, it will be found that the pfoperty 
 belonging to the authority will have no renting value, but will consist 
 of the materials of which the tanks and works are made with the com- 
 paratively small area of land upon which they were constructed, for 
 which but little money would be given if sold, whereas at Abingdon, if 
 the present mode of disposal were given up, the borough would 
 possess a property consisting of Cottage, Homestead, and 48 acres of 
 land which would at any time let for ;^i7o a year, and if sold would 
 realise ;£^5,ooo. Moreover the present charge on the ratepayers at 
 Aylesbury is ^^d. in the pound, whereas that at Abingdon is 4^d., in 
 respect of the respective outlay for sewage cleansing. 
 
 With regard to Hertford and Halstead the same observations will 
 apply with a wider difference between the two. At Hertford the charge 
 on the ratepayers (irrespective of the contribution of the New River 
 Company) is T^d. in the pound, whereas the charge at Halstead hardly 
 reaches as much as 3^. in the pound. It is true that at Hertford the 
 sewage is diluted with subsoil water to an extraordinary extent, whereas 
 at Halstead there is an absence of any sensible dilution, showing 
 distinctly the effect of an influx of foreign water and the necessity 
 of water-tight sewers, if economy is to be considered. It must 
 not be supposed that the quantity of liquid regulates the quantity of 
 land required for purification if the land is of a " suitably constituted " 
 character. If reference is made to the descriptions given of the opera- 
 tions at Merthyr, Kendal, Abingdon, and Malvern, it will be observed 
 that the quantity of water absorbed per acre day after day has exceeded 
 200,000 gallons. Wherever detention on the surface takes place it is 
 found to be due to the sludge deposited wMk wet, which forms a puddle 
 to resist infiltration. This resistance is very trifling in suitably constituted 
 soils. 
 
 At Hertford the sewage of 7,250 people is daily mixed with upwards 
 of 1,000,000 gallons of subsoil water. Still, if we have regard to every 
 day's experience in Intermittent Filtration, we shall be assured that 
 20 acres of the free soil surrounding Hertford would be amply sufficient 
 for the perfect and constant purification of the sewage of 7,250 persons 
 though it may be diluted by mixture with more than a miUion gallons 
 of subsoil water. 
 
 Should exception be taken to these Comparisons it would be well for 
 
92 
 
 the reader to examine the facts relating to the disposal of the sewage 
 of Birmingham. There one-third of the sewage is cleansed by treat- 
 ment on land, and two-thirds by chemical precipitation. The former 
 showed in 1878 a balance of annual receipts over annual expenditure 
 (exclusive of rent of the purchased land) of ^\,o6if iZs. "jd., whilst the 
 cost of the latter process (the chemical treatment) was ;^i 1,987 15^. 3^. 
 (See Journal of the Royal Agricultural Society of England. Second 
 Series, vol. xv'i, part i.) 
 
93 
 
 SEWAGE FARMING. 
 
 EXPERIENCES AND RESULTS. 
 
 It is not many years since several of the leading chemists in 
 Europe held out to the followers of the twin arts of agriculture and 
 horticulture the prospect of enormous returns from the use of human 
 refuse in their occupations ; the farmer and the gardener, in fact, were 
 alike told that though it might call forth a new class of cultivators as 
 " sewage farmers," they would each have it in their power by the use of 
 excretal matter to increase the production of food so rapidly and so 
 largely that it was difficult to limit the profit they severally would gain. 
 The benefit that such increased production would be to the world at 
 large was at the same time pointed out with equal force. 
 
 Boussingault showed that an adult gives off in his excrements as 
 much as 1 6 lbs. of nitrogen yearly, which is a quantity sufficient to 
 yield 800 lbs. of wheat and 900 lbs. of barley, while Baron Von Liebig 
 went so far as to say that each unit of the population can, on an average, 
 supply with nitrogen absorbed from the atmosphere, sufficient manurial 
 matter to raise from an acre of ground " the richest possible crop each 
 year;" — and no doubt of the accuracy of these statements has ever 
 been recorded on sufficient data to cause disbelief. 
 
 Somewhat more appositely to the utilization of sewage, Messrs. Chemists' 
 Lawes and Gilbert, the eminent chemists, whose efforts in the cause 
 of agriculture are so highly appreciated in this country, have shown, 
 that 8s. 4d. represents the intrinsic value of sewage per head of the 
 inhabitants of water-closet towns, whilst other equally well known 
 authorities on the subject have arrived at figures, some above and some 
 under this estimate. The consulting chemist of the Royal Agricultural 
 
 sewage. 
 
94 
 
 Society of England, Dr Voelcker, by taking the value of ammonia at 
 <)d. per lb., and that of phosphates at 2d. per lb., has declared the total 
 value of human excreta per head to be 9^. per annum. 
 
 These estimated values were doubtless well based on true analyses, and 
 are abstractedly correct, but it has been found in the practical utilization 
 of sewage that when the fertilising elements are diluted with 61 tons of 
 water per annum (the average quantity contributed by each individual 
 to the outflow from towns, i.e. — 25 gallons of sewage proper + 50 per 
 cent, of subsoil water x by 365 (days) H- by 224 gallons = 61 tons — ) 
 not only does the productive value shrink to a very small amount, but 
 that such a bulk of diluted sewage, if compulsorily applied (which too 
 often means inappropriately), actually causes mischief rather than benefit. 
 Instead of \\d. being the value, as it would appear to be by dividing 
 8^. 4if., the chemist's value of sewage per head, by 61, the number of 
 tons which it has been already explained represents the diluted quantity 
 of liquid per head to be dealt with, it is actually reduced by attendant 
 drawbacks to the present mode of application to much less than one 
 farthing per ton. 
 
 Even with such a greatly diminished value as a farthing a ton, how- 
 ever, the country has a valuable property which it is our duty to 
 preserve. Yet such a difference between estimated chemical value and 
 actual realisable value is a satire upon our practical character which 
 we should do our best to remove, for it is certain that \\d. is as much 
 too high as a farthing per ton is too little. To appreciate the quantity 
 of sewage at command, and to arrive at the true productive value of the 
 property at stake, it should be remembered that in England alone there 
 are 1 3 towns — excluding the Metropolis— which have populations above 
 100,000, 19 between 100,000 and 50,000, 178 between 50,000 and 
 10,000, and 549 between 10,000 and 2,000 ; and that if only half of these 
 towns, with an aggregate population of 5,000,000, ultimately determine 
 to utilise their liquid refuse by application to land, the annual quantity 
 at disposal will be 305,000,000 tons. This quantity at a farthing a ton 
 will amount to upwards of ;^3oo,ooo a-year which may be taken to 
 represent the annual value of upwards of 200,000 acres of unsewaged 
 land, or that of the farmed land of Huntingdonshire. 
 
 Setting on one side the chemist's estimate of i%d. per ton, the Uquid 
 sewage of 100 persons seems to have been adopted by common consent 
 as the average quantity that may be advantageously applied each year 
 to an acre of land. Upon what data this conclusion has been come to 
 
95 
 
 it IS difficult to say, for the sewage of loo persons would in quantity 
 amount to 6,ioo tons, which at the chemist's value would, be worth 
 upwards of ^£2$. 
 
 It can be readily understood that no tenant farmer if obliged to take 
 6,100 tons per acre, which is equivalent to a superincumbent depth of 
 5 feet, or 2^ times the average annual rainfall, would give even a farthing 
 a ton for it, — which would amount to ;^6 75. i-d. per acre, — though he 
 would gladly give a price calculated after the full rate of T.\d. per ton 
 if he could have what he wanted just at such times as he wanted it. 
 
 No single dressing of liquid, to be productive of benefit, should Depth of a 
 exceed an inch in depth, and directly the quantity applied to an acre of ^'^fs^j,™ 
 land exceeds that depth, which is equal to 100 tons, the surplus is 
 positive waste, which should not be paid for. All land laid out for 
 irrigation has sloping surfaces which cause the liquid to run down to 
 the lower portions of the surface and to rest there in slacks and 
 hollows until it is absorbed or evaporated, doing mischief in the mean- 
 time. The farmer paying rent for land with sewage soon finds this out. 
 He knows that he cannot profitably apply more than 20,000 gallons at 
 a dressing except to fallows, bare of vegetation, which no sewage farmer 
 ought to have in the growing seasons. 
 
 Experience, in fact, goes to prove that sewage, let its intrinsic value 
 be what it may, directly it is delivered to land by way of Surface Irriga- 
 tion, without that systematic arrangement which will secure regularity of 
 distribution in the quantities that will be beneficial, ceases to be of any 
 value at all. Without system the distribution of sewage on the surface 
 becomes what has been termed " intensive irrigation," or in other words 
 the "getting rid of the sewage in the quickest way," with an 
 indefinite chance of turning its fertilising ingredients to some account at 
 the same time, when harm rather than good is frequently done. 
 
 If we turn to the best examples of sewage farming we shall find 
 these statements exemphfied in different degrees. 
 
 The figures very accurately given by Mr. Morgan, when managing Lodge farm, 
 the Barking Farm for the Essex Reclamation Company in the last year Barking, 
 in which he published a Return, showed that he expended as much as 
 21,488 tons of sewage per acre on one crop of Italian rye grass, which 
 at \d. a ton, the least amount at which sewage has been valued by 
 chemists, would amount to ;^89 loy. %d., and at a farthing a ton to 
 ;^22 1$. 8d., which every practical farmer or gardener knows to be 
 unreasonable, and quite inconsistent with profit, because a very large 
 
96 
 
 proportion of the liquid must necessarily be unproductive of any 
 return whatever. 
 
 Leamington. Turning to what has been so patriotically done by the Earl ox 
 
 Warwick on the Heathcote Farm and on adjacent farms on the same 
 estate (the largest illustration of sewage utilization in England) upon 
 which the sewage of Leamington is applied, we find that whilst his 
 lordship pays the Corporation less than one-third of a farthing a ton, 
 it has been retailed to his tenants at a much less price, an arrange- 
 ment which is not surprising, seeing that the sewage was distributed 
 among them (in 1878) after the rate of 11,583 tons per acre irrigated. 
 
 Doncaster. On the Doncaster Farm, which has the advantage of excellent 
 
 management, as much as 17,505 tons per acre was applied in the 
 same year (1878) to rye grass, 6,455 to"s to mangolds, and 4,505 tons 
 to permanent pasture, which at a farthing a ton would amount to 
 upvirards of ;i^i8 4s. 8^d., jCfi 14^-. 5f(/., and jQ/^ tJi^. \od. re- 
 spectively. These figures are not quoted with the intention of prov- 
 ing that the sewage was not worth the sums set forth j — they are 
 given to show that so long as irrigation is conducted in the manner now 
 followed, an estimate of even one farthing a ton cannot be justified, and 
 if sewage is not worth a farthing a ton it may be well asked, how can 
 agriculture benefit by its use ? In fact these figures prove incon- 
 trovertibly the absurdity of placing any value at all on sewage distributed 
 in irregular quantities, and show distinctly the necessity of a different 
 treatment if the nation is to be advantaged in any sensible degree. 
 
 There is no disguising the fact that the constantly repeated attempts 
 to reconcile, in one operation, the two objects ol cleansing ^.vlA. profitably 
 applying sewage have brought the mind of the country into such a state 
 of confusion and disbehef in the power of obtaining any profit from 
 sewage utilization, that it will be almost impossible to re-establish a 
 different view. This is greatly due to the fact that up to this time 
 some of our most able men have been using the great influence of their 
 voice and pen in advocating the application of sewage to "ordinary 
 farming," with plough-made furrows and such like expedients, and have 
 declared — 
 
 " That sewage farming should not be dealt with as a distinct branch 
 of husbandry, but that in order to make it successful it must be 
 engrafted on ordinary agriculture !" 
 
 It is the object of the present treatise to show that if our fields are 
 really to benefit by the liquid refuse of our towns we ought to do just the 
 
97 
 
 reverse, assuming that by engrafting sewage farming on ordinary 
 agriculture it is meant that the hquid should continue to be distributed, 
 as at Leamington and Doncaster,* in irregular quantities at times when 
 it is not wanted. In neither of these cases has it been proved that a 
 tenant farmer could afford to pay one farthing a ton for the sewage 
 applied. All experiences tend to prove that the obligation to "get 
 rid" of a large quantity of sewage under all circumstances and condi- 
 tions, at night as well as day, on Sundays as well as week days, on 
 cropped lands as well as fallows, and at all stages of growth, from seed- 
 time to harvest, puts it beyond the reach of man to gain any real profit 
 from it. 
 
 Fortunately for the ratepayers of urban districts the last lo years 
 have conclusively shown, as I hope the instances given in this treatise 
 will further confirm, that a comparatively small extent of land deeply 
 drained and properly prepared, varying in extent, as already explained, 
 fiom I acre to i,ooo to i acre to 250 people, according to the nature of the 
 soil, will, if treated by Intermittent Filtration, under good management, 
 suffice for sewage purification per se, and allow of the growth of heavy 
 crops of grass, roots or vegetables at the same time. 
 
 Fortunately, too, for agriculture, it has been made equally clear that 
 it is quit© practicable to prepare and use as a safety-valve, a proportion 
 of any sized farm for Intermittent Filtration whilst delivering to the 
 remainder of the farm only so much sewage as the occupier would deem 
 desirable, so that in fact, if he requires a large quantity as a dressing for 
 Rye Grass or other artificial grasses, or a comparatively small quantity 
 for roots or cabbages, he can have just what he wants and no more. 
 
 It can only be by some such "safety-valve arrangement" that the 
 true value of sewage can be realised ; not that a sewage farmer may ever 
 be able to pay i\d. per ton for what may be delivered to him, though, as 
 already stated, it is certain that he will be better able to pay even that 
 price for what he actually requires than a farthing per ton when the 
 liquid is crowded upon him in such quantities and at such times 
 as he cannot utilise it. In asserting this, the writer speaks from 
 a lengthened experience, first as an ordinary farmer, and afterwards 
 as a sewage farmer. 
 
 * The experience at Cheltenham does not help to solve this question. There the 
 sewage is cleansed by surface irrigation over land which is let by tender annually 
 subject to the distribution of the sewage as the Sanitary Authority thinks well to 
 apply it for its own purpose. The return for the sewage after the rent of the land is 
 paid is reckoned to be i\d. per head per annum of the population. 
 
98 
 
 Qualifications 
 of a sewage 
 farmer. 
 
 As sewage farming is now conducted, with irregular supplies of liquid 
 and surfaces ill-formed,- — under the supposition that it is economical to 
 adopt the rough-and-ready style of preparation and distribution amidst 
 obligations and drawbacks of the formidable character already mentioned 
 — it is found that the greater the width of land laid out to receive sewage 
 by way of irrigation the greater is the loss to those who pay for the sewage 
 used, showing distinctly that from an agricultural point of view the pre- 
 sent mode of irrigation with sewage is the reverse of what it should 
 be in the interests of the nation. In fact at the present time there are 
 various sewage farms to be hired at rents less in amount than would be 
 given for the same land without sewage. Can anything more con- 
 clusively prove that the mode of distributing the sewage is at fault? 
 With the intrinsic value of sewage, if^. per ton, it could hardly have 
 been supposed that we should be obliged to acknowledge this fact. 
 
 Among the instances given in the preceding examples that of Great 
 Malvern may best serve to show what may be done in the way of com- 
 bination of Intermittent Filtration with Surface Irrigation in order to 
 obtain from sewage a satisfactory return. At Malvern the daily dry 
 weather overflow, amounting to 350,000 gallons, may be concentrated on 
 any one of the 1 1 areas devoted to Intermittent Filtration, consisting of 
 a little more than an acre, and the 35 remaining acres forming the 
 cultivation of the farm relieved of sewage altogether. By judicious use 
 of the filtration areas any part of the farm may receive that quantity of 
 sewage for fertilising or watering as may best conduce to the largest 
 money return, and in this case provision is made for sewaging adjacent 
 lands whenever it may be found profitable to do so. Special arrange- 
 ments, too, are made for dealing satisfactorily with surplus (storm) 
 water. 
 
 The same experiences that have made it manifest that to secure 
 any chance of profit in sewage farming, the liquid must be distributed 
 in regular quantities and at proper times, has also satisfied all practical men 
 that the early expectations entertained as to the general applicability of 
 sewage to ordinary farm crops cannot be realised and that a sewage 
 farmer to qualify himself for success must serve a special apprenticeship 
 to the occupation. Moreover, it has been made clear that an ordinary 
 farmer is no better qualified to deal with sewage without such apprentice- 
 ship than a gardener, for not only is it necessary to know what grasses 
 and vegetables can be best treated by sewage and to regulate the 
 frequency of application and the quantity of liquid to gain the best 
 
99 
 
 return, but it is absolutely essential that he should be able to effect the 
 
 best and readiest sale of his crops when fit for market and so to 
 
 conduct his operations with reference to the demands of local markets 
 
 and of such other markets as he can best reach, as will conduce to the 
 
 growth of only such crops as he can most readily sell. By this means 
 
 he will reduce to a minimum the losses incidental to all food production. 
 
 for it is quite certain that in the long run the man who sells the most at 
 
 the right moment, and who aims at converting into milk or meat what he 
 
 cannot sell, is the person who will make the most money. To do Buildings 
 
 this it is absolutely requisite that every sewage farm should have upon 
 
 it sufficient buildings to house a proper number of milch cows and 
 
 pigs to consume a portion of each season's produce. 
 
 It is essential, in fact, that a tenant of a sewage farm should combine 
 in his own capabilities the practical qualities of a farmer, a gardener, 
 and a market salesman, which will induce him to avoid all treatment 
 of a dilettante character and lead him to embrace in his management the 
 growth of such crops only as will keep him most favourably before the 
 markets he serves. Many of the ordinary farm crops are injured by 
 the application of sewage to them. Cereal and pulse crops, instead 
 of being benefited by its direct application to them while in growth, 
 are damaged by the increase of straw at the expense of the grain ; — 
 potatoes and turnips are also injuriously affected in a like manner. 
 Kohl Rabi seems to do better. 
 
 It is equally true that heavy crops of both grass and vegetables may Rye grass, 
 be produced without the capability of selling them. Not many years 
 back the possibility of growing Italian rye grass without the certainty of 
 sale or conversion was ridiculed as an absurdity, yet the last few years 
 have satisfied all sewage farmers that it is not only possible to grow more 
 rye grass than can be sold but that if retained for conversion either 
 into milk or into hay, it is very problematical whe);her ip one way or 
 another, some loss does not attend the operation. Still there are crops 
 which when advantageously selected cannot fail to yield a profit if the 
 liquid is rightly applied. 
 
 Up to a limited extent rye grass of all productions is that which 
 best responds to the use of sewage unless it be prickly comfrey, 
 which is an excellent forage plant for horses and may be profitably 
 consumed with rye grass by cows. Moreover, it would appear that 
 it can never be overdosed with sewage. 
 
 All the cabbage tribe are also greedy of sewage and although in Cabbages. 
 
 G 2 
 
lOO 
 
 Mangolds. 
 
 Carrots and 
 parsnips. 
 
 certain seasons it is very easy to have too many for market, there is no 
 doubt that in the long run they pay well, particularly if pigs are kept on 
 the farm to consume any unsold surplus. The Enfield Market, Colewort, 
 and Ox-heart cabbages, if they stand through the frost of winter, realise 
 a good return in early summer, while savoys and drumheads— which 
 latter, though more frequently treated as the food of cattle, sell remarkably 
 well to the inhabitants of the manufacturing and mining districts, — are 
 generally very saleable in late autumn and winter. Under good 
 management the two crops of cabbages of summer and winter are 
 grown in the same year on the same land, — that is, the summer 
 cabbages planted in October are cut in May or June, when the land 
 is again prepared for savoy and drumhead cabbages, which may be 
 planted in sufficient time to be cut the following winter and the ground 
 cleared in time for a succession of roots. 
 
 But on the whole, mangolds (long red, tankard and globe) form the 
 best crop for the sewage farmer if the selected seed is good and it is 
 carefully sown, and advantage is taken of a command of sewage for 
 timely watering to secure a plant. The weight of crop will always vary 
 with the temperature of the summer, but under any circumstances the 
 crop from a sewage farm will, compared with that from an ordinary 
 farm, surpass it in both weight and quality. It would appear that if 
 the land is well drained so that the liquid readily percolates, mangolds 
 of all roots will flourish best with a superabundance of liquid. This 
 year (1880) the writer has grown on 13 acres of land, forming part of 
 the filtration areas at Hitchin, 400 tons of these roots, which is equal to 
 31 tons to an acre. These 13 acres have received, perhaps twice a 
 week, 100,000 gallons per acre. These mangolds were raised, carried 
 from the peaty soil, and clamped ready for sale at a cost of ;^45, so 
 that if they should sell in April or May at ;^i a ton clear of carriage, 
 they will realise ;^2 7 6j'. an acre. 
 
 Carrots and parsnips do equally well in a free sandy soil. At Forfar 
 this year (1880) a price equal tO;^56 an acre was gained by the growth 
 of carrots on the filtration areas. On inferior free soils, the Intermediate 
 Red Carrots are best, but on naturally deep sandy loams the Altringham 
 Reds yield the greater weight. White Carrots for cattle pay well in 
 suitable soils, but with them and all other sorts of carrots — as well as 
 with parsnips — no amount of sewage will make an unsuitable soil 
 productive of heavy crops. 
 
 Sewage farmers as a rule should avoid the growth of crops which 
 
lOI 
 
 have not been well tried. Much money is lost by experiments in 
 
 refined vegetable gardening, such as the growth of Lettuces, Parsley, 
 
 Vegetable Marrow, Sugar Beet, &c. 
 
 Probably onions, if the soil is compact and suits them, and good Onions. 
 
 judgment is used in watering them, pay better than any other crop, but 
 
 there are few places where this root will succeed. They are altogether 
 
 unfit for the superabundant watering of filtration ground. 
 
 To a small extent rhubarb and celery may be advantageously Rhubarb, 
 
 Celery, 
 grown. 
 
 CONCLUSIONS. 
 
 This Treatise would fail in one of its purposes if it were brought to 
 a close without an expression on the part of the Author, both as an 
 Engineer and as a Farmer, of the conclusions to which he has been 
 brought by the experiences of the last lo years in relation to the difierent 
 modes of sewage disposal now practised in this country, and the effect 
 they have had in promoting the production of food for our rapidly 
 increasing population. 
 The conclusions are — 
 
 First. — Excluding from consideration sea- board towns, the sewage of 
 which it may be expedient on all grounds to discharge direct 
 into the sea, the instances are few in which the liquid refuse 
 discharged from human habitations may not be more econo- 
 mically cleansed by recourse to land than by any chemical 
 precipitation. 
 Second. — That the exceptions are only those where land cannot be 
 
 obtained. 
 Third. — That the more minute floating solid matters, generally 
 called "sludge," which cannot be separated from the liquid 
 by screens designed to arrest the larger solids, form no bar 
 to the use of land as a purifier. Such ingredients when con- 
 veyed to land, where they are always wanted, instead of 
 clogging it, help to make it more percolative and more pro- 
 ductive than it would be if such materials were withheld. 
 Fourth. — That if, instead of leaving sewage when applied to land 
 to flow where it will over irregular surfaces in the varying 
 quantities in which it is usually discharged from towns, proper 
 
I02 
 
 Steps were taken to deliver for Surface Irrigation only such 
 quantities as are wanted by the cultivator by taking advantage 
 of the power we always possess of cleansing any quantity of 
 sewage by Intermittent Filtration through a small area of 
 land, not only would Sanitary Authorities conform to the 
 requirements of the law in relation to the purification of 
 their sewage with a less charge upon contributing ratepayers than 
 is involved in any other treatment, but Agriculture would secure 
 a benefit in its profitable utilization at present withheld ; and 
 Fifth. — That by adopting properly- devised Intermittent Filtration 
 areas, which allow of no overflow from the surface into rivers, 
 nor any discharge but from the underdrains (except in times 
 of excessive rainfall, and then only by regulated "Storm 
 Overflows "), the constantly recurring evils due to inattention 
 on the part of those who have the care of the disposal works, 
 are completely removed. 
 
INDEX. 
 
 Abingdon. Works described 
 
 Cost ofWorks 
 
 Intermittent Filtration 
 
 Wide Irrigation... 
 
 Character of Effluent 
 
 Result on the Ratepayers 
 
 No separation of Sludge 
 
 Rent of Farm 
 
 Absorptive powers of soils ... 
 Agriculture, benefit to be derived by 
 Analjfsis of Effluent at Abingdon . . , 
 
 Barnsley 
 
 Halstead 
 
 - — • Hitchin 
 
 -Malvern 
 
 Merthyr Tydfil 
 
 Analysis of soil at Barnsley 
 
 Page 
 
 62 
 
 Attfield, Professor, Analyses 
 
 B 
 
 63, 
 
 SO 
 102 
 
 63 
 79 1 
 • ■• 75 
 ... 83 
 ... 71 
 .- S3 
 ... 77 
 7>. 75, 
 79.83 
 
 Barnsley. Works described 
 
 Cost of Works ... 
 
 Effluent, character of 
 
 Analysis of soil 
 
 Diagram of Sewage cleansed 
 
 daily... 
 Buildings on Sewage Farms 
 
 75 
 
 99 
 
 Chemists' value of sewage ... 37,93 
 Chemical precipitation compared 
 
 with land treatment 89 
 
 Clayey loam at Barnsley, analysis of 77 
 Clay soils to be avoided or specially 
 
 treated ... 49 
 
 Clogging of soils by sludge refuted 44, 88 
 
 Convalescent Hospital at Walton ... 87 
 Cost of Sewage Disposal Works at 
 
 Abingdon 63 
 
 Barnsley 78 
 
 Forfar 67 
 
 Halstead 74 
 
 Hitchin 82 
 
 Kendal 60 
 
 Malvern ... 71 
 
 Merthyr Tydfil 54 
 
 Crops for .Sewage Farms 99 
 
 Crops at Hitchin, value of 82 
 
 Cost of Intermittent Filtration, ex- 
 aggerated 52, 
 
 D 
 
 Detritus, Road 
 Distribution of Sewage 
 
 59 
 
 43 
 97 
 
 Page 
 Distribution of Sewage, prevailing 
 
 mode repugnant to profit 98 
 
 Doncaster Farm. Quantity of sewage 
 
 used 96 
 
 E 
 
 Earlsdon. Description of Works 
 
 Sewage Regulator 
 
 Effluent, Analysis of, at Abingdon 
 
 Barnsley... 
 
 Halstead 
 
 Hitchin 
 
 Malvern, Great 
 
 Merthyr Tydfil 
 
 Forfar, Description of Works 
 
 Cost of Works 
 
 — — Intermittent Filtration . . . 
 
 Return from Crops 
 
 Sewage Farm, Profit from 
 
 H 
 
 Halstead. Works described 
 
 Cost of Works 
 
 Intermittent Filtration... 
 
 Surface Irrigation 
 
 Effluent, character of ... 
 
 Effect on Ratepayers ... 
 
 Wind Engine used 
 
 Osiers 
 
 Hitchin. Works described . . . 
 
 Cost of Works 
 
 • Intermittent Filtration... 
 
 Effluent, character of ... 
 
 Charge on Ratepayers . . . 
 
 Tenants' crops ; yield . . . 
 
 Subsoil Water ... 
 
 Surface Water 
 
 Peaty Soil 
 
 85 
 
 63 
 79 
 75 
 83 
 71 
 S3 
 
 64 
 
 •/ 
 
 72 
 
 79 
 
 So 
 
 Intermittent Filtration at Abingdon 62 
 
 Barnsley 76 
 
 —Forfar 65 
 
 Halstead 73 
 
 Hitchin 81 
 
 Kendal 58 
 
 Malvern ... 70 
 
 Merthyr Tydfil 52 
 
 Intermittent Filtration defined 30, 31 
 
ro4 
 
 K 
 
 Kendal. Works described . . . 
 
 Cost of 
 
 ■ Result of Intermittent Filtration , 
 
 on Ratepayers 
 
 • Cliaracter of Effluent . . . 
 
 Official misrepresentations 
 
 Page 
 
 57 
 
 Land treatment compared with 
 
 chemical precipitation ... ... 89 
 
 suitable ... ... ... ... 49 
 
 unsuitable 49 
 
 always resaleable if treatment 
 
 altered 91 
 
 extent required 33 
 
 M 
 
 Malvern, Great. Works described... 1 
 
 . Cost of Works ... 
 
 Intermittent Filtration as 
 
 Safety Valve i-68 
 
 Surface Irrigation 
 
 . Effluent, Analysis of ... 
 
 Osiers for Storm Water ... ^ 
 
 Mangolds as a sewage crop 
 
 Merthyr Tydfil.' Works described... ' 
 
 Cost of Works ... 
 
 Remarkable Result of Inter- 
 mittent Filtration [-51 
 
 . ■ Surface Irrigation 
 
 Effluent, character of . . . 
 
 Official misrepresentations 
 
 Midden Towns, character of Sewage 
 from 35 
 
 O 
 
 Oakham. Mode of disposal 
 
 Return from crops 
 
 Overflows, Storm, indispensable ... 47 
 Osier Beds for cleansing Storm 
 
 Waters 48 
 
 Official misrepresentation at Kendal 59 
 Merthyr Tydfil 52 
 
 Prickley comfrey ... ... ... 99 
 
 Profit from Sewage Farming ; how 
 to begained... ... ... 98,99 
 
 Qualifications of a Sewage Farmer ... 98 
 R 
 
 Radford. Sewage Regulator Tank ) „ 
 
 ■^ Mode of Disposal at \ 5 
 
 Regulator, Sewage, for Villages, De- 
 - scription of . . : 85 
 
 Page 
 Read and Rawlinson's, Messrs., Re- 
 port _ 31.38, 52. 59 
 
 Retentive powers of soils, Influence 
 
 of ... ... 50 
 
 Rivers Pollution Commissioners j j •'^ ' 
 
 Suggestion of Intermittent 
 
 Filtration 3°. 31 
 
 Standards proposed by 
 anticipated Objections to 
 
 Intermittent Filtration removed ... 
 
 Road detritus 
 
 Rules to be observed in Filtration 
 
 Works 
 
 Rye Grass, Italian, as a Sewage 
 
 Crop 
 
 S 
 
 Sewage Disposal Works necessary at 
 sea-board towns 
 
 Towns on Tidal Rivers ... 
 
 Towns, Inland 
 
 at Abingdon 
 
 Barnsley '. 
 
 Convalescent Hospital, Walton 
 
 Forfar 
 
 Halstead 
 
 Hitchin ... 
 
 Kendal ... 
 
 Malvern, Great 
 
 Merthyr Tydfil 
 
 Oakham... 
 
 Radford and Earlsdon 
 
 Sewage, character of . . . 
 
 Temperature of. 
 
 Quantity of 
 
 Actual value of... 
 
 Chemists' value 
 
 Sewage Farming 
 
 Experiences and Results of the 
 
 Author 
 
 profit from 
 
 Intermittent Filtration the safety 
 
 valve of 
 
 Present mode of distribution ir- 
 reconcilable with profit 
 
 Effect on Agriculture 
 
 Sewage Farmer, Qualifications of ... 
 
 Sewage Farm at Abingdon 
 
 Barnsley 
 
 Barking 
 
 Doncaster 
 
 Forfar ... 
 
 Heathcote Farm, Leamington 
 
 Halstead 
 
 Hitchin ... 
 
 Kendal 
 
 Malvern 
 
 . Merthyr Tydfil 
 
 Oakham 
 
 Sewage Farms, Cultivation of 
 
 Saleable crops for 
 
 Buildings indispensable to profit 
 
 27 
 
 32 
 43 
 
 87 
 
 99 
 
 23 
 
 24 
 
 26 
 
 62 
 
 75 
 
 87 
 
 64 
 
 ■■ 72 
 
 .. 79 
 
 •■ 57 
 
 .. 68 
 
 •• SI 
 .. 84 
 .. 8s 
 ■• 35 
 • • 45 
 .. 36 
 41, 94 
 37,93 
 93 
 
 93 
 100 
 
 97 
 
 97 
 98 
 q8 
 62 
 75 
 95 
 96 
 64 
 96 
 72 
 79 
 57 
 68 
 
 51 
 84 
 
 99 
 99 
 99 
 
lo5 
 
 Sewage for watering crops 
 
 Sewage Effluent, when available for 
 
 re-use in trade 
 
 Soils suitable 
 
 unsuitable 
 
 Analysis.of at Bamsley... 
 
 Standards of purity recommended by 
 
 Rivers Pollution Commissioners .. 
 adopted by the Thames Con 
 
 servators 
 
 Subsoil Water... 
 
 Surface Waters ... 
 
 Sludge beneficial to land 
 
 no bar to Irrigation or Filtration 
 
 value of 
 
 Solid matters distributed amongst 
 
 growing vegetation 
 
 Storm Overflows 
 
 with Osiers 
 
 Surface Irrigation combined with In 
 
 termittent Filtration at Halstead. 
 
 at Malvern 
 
 at Abingdon 
 
 Salesmen of Sewage produce 
 
 Temperature of Sewage 
 Thames Valley Sewage Disposal 
 Tidal Rivers, Towns upon ... 
 Towns classified 
 
 Page 
 
 42 
 
 42 
 49 
 49 
 77 
 
 27 
 
 25 
 
 36 
 
 37 
 45 
 
 44 
 
 45 
 47 
 48 
 
 73 
 70 
 62 
 99 
 
 45 
 29 
 
 24 
 23 
 
 Towns Inland 
 
 Trade liquids 
 
 Trade, Sewage Effluent available for 
 
 Page 
 26 
 
 35 
 
 42 
 
 Value of Sewage, chemical and ac- 
 tual ' 
 
 at Abingdon 
 
 at Barking 
 
 at Cheltenham 
 
 at Doncaster 
 
 at Leamington ... 
 
 Value of Sewage Farms, letting 
 
 How it may be increased 
 
 Voelcker, Dr. A., F.R.S. Report 
 
 on Sludge and Sewage Manures . . . 
 
 Analysis of Soils at Barnsley ... 
 
 W 
 
 Walton Convalescent Hospital 
 Wanklyn, Analysis of Effluent at 
 
 Hitchin, by Professor 
 
 Water Closet Towns, character of 
 
 Sewage from ... 
 
 Watering by Sewage 
 
 Wind as a Motor 
 
 Engine at Halstead 
 
 1 94 
 64 
 
 95 
 96 
 96 
 96 
 62 
 99 
 
 38 
 77 
 
 87 
 
 83 
 
 35 
 42 
 
 73 
 73 
 
 INDEX TO THE ADDITIONAL MATTER OF 
 SECOND EDITION. 
 
 Abingdon. Reviewed (1884) 
 
 Barnsley. ,, ,, 
 
 Commission (Royal) on Metropolitan 
 Sewage Discharge on Intermittent 
 Filtration 
 
 Dewsbury. Works described and re- 
 sults given 
 
 Forfar. Reviewed (1884) 
 
 Halstead. „ „ 
 
 Hitchin. „ „ , 
 
 Intermittent Filtration suggested for 
 the disposal of the Metropolitan 
 Sewage by the Royal Commission 
 on Metropolitan Sewage Discharge 
 
 Kendal. Reviewed (1884) ... 
 
 Malvern, Great. Reviewed (1884)... 
 
 Management or mismanagement of 
 Filtration areas 
 
 Page 
 II 
 14 
 
 15 
 II 
 
 14 
 
 II 
 13 
 
 Merthyr Tydfil. Reviewed (1884) ... 
 
 Metropolitan Sewage. Purification 
 by Intermittent Filtration feasible 
 
 Oakham. Reviewed (1884) 
 
 Results of four years' further expe- 
 rience in works of Intermittent Fil- 
 tration ^ 
 
 Royal Commission on Metropolitan 
 Sewage Discharge. Observations 
 on Intermittent Filtration 
 
 Separation of solids in connection 
 with Intermittent Filtration 
 
 Watford. Works described and re- 
 sults given 
 
 Withington. Works described and 
 results given 
 
 Page 
 
 15 
 
 20 
 
 18 
 
 17 
 
 HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN'S LANE. 
 
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 HANDBOOK OF HOUSE SANITATION, 
 
 FOR ALL PERSONS SEEKING A HEALTHY HOME. 
 
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 This Work describes the latest approved Sanitary Arrangements 
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 Methods of Ventilating and Draining Houses, and of Raising, 
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