453 



NA TURE 



[March 19, 1903 



" The following book has been written in response 

 to several requests for an account of the methods of 

 analysis in use in the laboratory of the Manchester 

 Corporation Sewage Works. 



" Through the courtesy of Mr. F. Scudder, the 

 author has been able to include descriptions of some 

 of the more important processes employed in the 

 laboratory of the Mersey and Irwell Joint Committee. 



" In general it may be said that the Joint Com- 

 mittee's methods are designed for cases where 

 samples from different works have to be critically 

 examined, the Manchester methods for the analysis 

 of a large number of samples of sewage and effluents 

 of the same general character. 



" The successful application of modern bacterial 

 processes will necessitate careful chemical control. 

 It is hoped, therefore, that the following book will 

 prove of use to the increasing number of chemists 

 who are interested in the scientific treatment of 

 sewage. 



" The methods here described are such as a con- 

 siderable experience has shown to be capable of being 

 rapidly executed, and of giving results of an accuracy 

 amply sufficient for practical requirements." 



The' book opens with a very brief description of 

 the general principles of sewage purification, divided 

 under the two headings : — (a) mechanical or disposal 

 processes ; (b) biological or purification processes, with 

 regard to the second of which the author writes : — 



" The changes which take place in all these 

 biological processes are much more complex than those 

 which are effected by any of the mechanical or dis- 

 posal methods in class (a), and chemical control is 

 absolutely necessary if they are to be maintained in 

 their greatest efficiency." 



The few pages which are devoted to this section 

 might, we think, be extended with advantage in a 

 future edition. Even allowing for the fact that the 

 work is one intended to deal with analytical methods, 

 a somewhat fuller summary — so far as present know- 

 ledge goes — of the changes which take place in septic 

 tanks and bacterial filters, from the pen of one who 

 has made a special study of those points, could not 

 fail to be of direct benefit to the laboratory worker. 

 Such a summary would almost certainly stimulate his 

 interest in the methods with which the book subse- 

 quently deals. 



After a short discussion on the gauging of sewage 

 flow and upon methods of sampling, the latter a 

 point on which it is difficult to lay too much stress, 

 the author goes on (p. n) to indicate what in his 

 opinion are the chief chemical data required to deter- 

 mine the amount of impurity in sewage and effluent, 

 the working out of these data being given later in 

 the book. A further portion of the chapter is devoted 

 to the " method of recording results," and here we 

 might add that it is very desirable that some uniform 

 system of records should be adopted throughout 

 the country. The chapter closes with a section 

 on the degree of purity necessary in an effluent, some 

 of the provisional standards adopted by different 

 Rivers' Boards being quoted. This question of 

 standards is too large and thorny a one to be entered 



NO. 1 742, VOL. 67] 



into within the limits of a short review, but the author 

 rightly emphasises the point that an effluent should be 

 purified to such a degree that it will not take up 

 oxygen from the water of any stream into which it 

 may flow. 



In chapter ii. the well-known " oxygen absorbed " 

 test is discussed at length, and full directions are 

 given for carrying it out ; one advantage of this test 

 is that a simple modification of the " three minutes' ' 

 test can be applied by any intelligent workman. The 

 chapter concludes with a description of Mr. Scudder"s 

 " incubator test," which is now so widely employed. 



In the section dealing with the determination of 

 free and " albuminoid " ammonia, the methods fol- 

 lowed both in the Manchester Corporation and in the 

 Mersey and Irwell laboratories are detailed at length 

 (p. 44 ct seq.). The accurate estimation of albuminoid 

 ammonia in sewage effluents is not so simple as it is 

 usually assumed to be, and, as it is a point of much 

 importance, it would be well if some more or less 

 uniform system of procedure could be generally fol- 

 lowed. 



The determination of nitrates (p. 61) is one of the 

 most important of all estimations in a sewage effluent. 

 The Gladstone-Tribe method (reduction with the 

 copper-zinc couple), which Mr. Fowler himself uses, 

 is probably the most accurate of any, but it has the 

 disadvantage of requiring twelve to twenty-four hours 

 for completion. It is to be noted here that the author 

 recommends the preliminary expulsion of any excess 

 of ammonia present by distillation with steam — a 

 plan which is perhaps better than by simple boiling 

 in an open flask. At the same time a loss of nitrogen 

 is apt to occur here if nitrites are present in any 

 quantity — at least, this is the case with the boiling 

 procedure; it can, however, be prevented, as has been 

 shown by P. Frankland, by the previous addition of a 

 small quantity of some alkali. 



In detailing several processes for the determination 

 of dissolved oxygen in effluents, a reference to 

 Winkler's chloride of manganese method, as modified 

 by Rideal, might with advantage have been included. 



On pp. 82-85, the determination of the rate of ab- 

 sorption of dissolved oxygen by an effluent — perhaps 

 the most important of all the chemical tests — is ex- 

 plained, and various examples are cited. 



In the remaining sections of the book there are 

 to be found such important items as the determina- 

 tion of solids in suspension, of supreme consequence 

 in the case of a tank liquor and of an effluent which 

 passes directly into a stream ; the collection and ex- 

 amination of the gases evolved from septic tanks and 

 in the interior of filter beds, &c. But enough has 

 already been said to show the comprehensive and exact 

 character of this little volume. 



Before closing, two omissions may perhaps be re- 

 ferred to, viz. (1) in any book dealing with the 

 analysis of sewages and effluents, one might naturally 

 expect a reference to be made to the work of the late 

 Sir E. Frankland, Dupre and Adeney ; and (2) it is 



