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THURSDAY, APRIL 28, i5 



BACTERIOLYSIS OF SEWAGE. 

 The Purification of Sewage and Water. By W. J. 

 Dibdin, F.I.C., F.C.S., &c., late Chemist and Super- 

 intending Gas Examiner to the London County 

 Council and the late Metropolitan Board of Works. 

 Pp. XV + 248. Royal 8vo. (London : The Sanitary 

 Publishing Company, Ltd., 1897.) 



RECENTLY there has been an astonishing and sudden 

 revival of interest in the question of the action of 

 bacteria on dead organic matter. Pasteur's experiments 

 on the production of disease by morbific germs were so 

 brilliant that, for long, most workers at the subject 

 kept very much in one groove ; still there have always 

 been those who, working very quietly, have been ac- 

 cumulating knowledge concerning the action of bacteria 

 on dead material, and the part these organisms play in 

 the process of disintegration of effete matter. 



It has, however, long been known that in nature various 

 processes of purification were undoubtedly intimately 

 associated with the life-history of special groups of 

 bacteria. Certain of these organisms, moreover, have 

 been recognised as playing a most important part in 

 bringing organic material into such condition that it 

 may be readily oxidised ; and in both France and Eng- 

 land investigators have studied this action, especially 

 in connection with the organisms that are associated 

 with the process of nitrification. It is somewhat 

 remarkable that notwithstanding these numerous ex- 

 periments, and in spite of the fact that the importance 

 of the part which bacteria play in bringing about natural 

 decomposition, nitrification and similar chemical pro- 

 cesses had been so early recognised, no systematic 

 attempt on any large scale had until comparatively re- 

 cently been made to carry out, artificially, what was 

 recognised as being done on a most extensive scale in 

 nature's laboratory. When once, however, a commence- 

 ment had been made, the course of events was by no 

 means slow, and many investigators soon turned their 

 attention to the question of the disintegration of the 

 organic matter in sewage, its oxidation and " mineral- 

 isation." Amongst these later workers, Mr. W. J. 

 Dibdin has taken an important position, and, in con- 

 nection with his office as chemist to the London County 

 Council, carried on a series of experiments on the bac- 

 terial purification of sewage, which in future will certainly 

 be looked upon as constituting one of the most important 

 parts of the pioneer work on the subject that has been 

 carried out in this country. As the outcome of this 

 v/ork, Mr. Dibdin has published in book form a col- 

 lected series of articles on the purification of sewage and 

 water ; and for those who wish to obtain, in clear and 

 concise form, an account of certain of the bacteriological 

 processes involved in this purification, and who wish to 

 have a summary of the chemical changes and results 

 obtained, no better book is at present published. Now 

 that the question is looked upon as of sufficient im- 

 portance to demand the appointment of a Royal Com- 

 mission, to assist the Local Government Board to gather 

 NO. 1487, VOL. 57] 



information, some such book as that now before us comes 

 very opportunely. It is fortunate, indeed, that the task of 

 supplying such a book has been undertaken by one 

 whose knowledge of the chemical processes involved is of 

 a very wide and practical character, who has a fair know- 

 ledge of the essential details of bacteriology, but who,, 

 more important still, has had a very wide experience of the 

 actual working of biological filters. The mass of material 

 accumulated in this book does not at first sight appear, 

 as the conclusions are usually so pithily put, and in such 

 simple language, that the enormous amount of work and 

 systematic observation on which they are founded is 

 sometimes almost lost sight of. 



In order to convey some idea of the scope of this work, 

 it may be well to give a brief outline of the ground covered, 

 by Mr. Dibdin. After a couple of introductory chapters 

 on the " history of putrefaction " and of the attempts that 

 have, from time to time, been made to interfere with the 

 process of putrefaction in sewage and in river- water, and 

 after describing in some detail the various processes of 

 disinfection, deodorisation, precipitation, and ordinary 

 filtration, a short description of the now famous Massa- 

 chusetts experiments is given. Then follows a very full 

 account of a series of experiments carried out on the 

 purification of London sewage in biological filter-beds 

 at Barking, and the nature and amount of purification^ 

 brought about in these filter-beds indicated, the measure- 

 ment of the purification being taken {a) from the amount 

 of oxygen absorbed ; {b) from the amount of albuminoid 

 ammonia got rid of ; and {c) the increase in the quantity 

 of nitrates. By passing the sewage intermittently 

 through these filters, and by allowing them to rest and 

 become aerated between the charges, it was found that 

 a purification of from 41 to 85 per cent, was obtained ;. 

 the whole of the organic matter in suspension was com- 

 pletely removed, and an effluent, in most cases fit to be 

 sent into rivers, was obtained. This purification goes- 

 on at the rate of about three-quarters of a million- 

 gallons per acre of biological filter. 



An installation at Sutton was worked on somewhat 

 similar lines, but here the filtrate from one bacteria tank, 

 was passed through a second, in which the filtering 

 material was of finer grain ; by this means still better 

 results were obtained, 80 per cent, of purification being 

 about the average obtained. The final filtrates were 

 free from all objectionable odour, and remained per- 

 fectly sweet on being kept in either open or closed vessels. 

 At both Barking and Sutton the coarse suspended 

 matter was strained out and buried, and the whole of 

 the subsequent changes were supposed to be due to the 

 action of aerobic organisms. 



^ir. Dibdin then gives a description of a system 

 which has been worked out by Scott-Moncrieff at Ash- 

 stead, and by Cameron at Exeter, who both use aiv 

 anaerobic chamber in order to initiate an active pre- 

 liminary breaking-down of the organic matter in the 

 sewage before aerobic organisms are allowed to act 

 upon it. They hold that in this way a more active dis- 

 integration of the organic matter is obtained ; whilst, in 

 addition, a process of peptonisation is carried on, with 

 the result that a large quantity of the solid material is 

 quickly thrown into solution, in which form it can be 



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