%o8 SEWAGE AND ITS PURIFICATION 



The basic amines are of two classes : 



(i) Non-volatile crystalline compounds known as ptomaines 

 and leucomaines. They are poisonous, but that they are 

 destroyed in the subsequent aerobic treatment is shown by the 

 fact that the final effluents are not poisonous to fish. 



(2) Volatile bases or substituted ammonias, usually of strong*] 

 odours and alkaline. These, in the ordinary method of analysis 

 by distillation, are partly put down as " free ammonia," which 

 includes not only the ammonia existing as carbonate, but also 

 that combined with the organic acids as salts, as well as such 

 compound ammonias as react with Nessler test. Many years 

 ago Young pointed out that in the usual mode of distillation 

 a great deal of volatile nitrogenous matter escaped which was 

 not recorded by Nessler test. The Wanklyn determination j 

 also gives an " albuminoid ammonia " which is far short of the 

 fixed organic nitrogenous matter, probably accounting for such 

 low figures as 0*34 (with 13*8 of chlorine) and 0*24 (with 10*3] 

 of chlorine) for raw sewages in the recent Manchester and other 

 reports. The Kjeldahl process can be made to give the whole 

 of the ammoniacal and organic nitrogen. 



In a septic tank effluent I lately found by fractionation of 

 the hydrochlorides, in parts per 100,000 : actual ammonia, 3*48 ; 

 monomethylamine (CH3NH2), 0*844; trimethylamine, traces; 

 the original having given 4*6 parts of " free ammonia " and (by 

 Kjeldahl) i*g8 parts of fixed organic nitrogen, with a chlorine 

 content of 6*2. 



Trimethylamine has a fishy smell, which is very marked 

 in some sewages. B. urece^ B. prodigiosus, and B. fluorescens 

 putridus develop this compound during putrefaction. Amy- 

 lamine and others are also found. The chief importance of 

 the group lies in — (i) their volatility and odours; (2) their 

 removing carbon as well as nitrogen ; (3) the toxic nature 

 of some, by which they hinder the subsequent nitrification. 

 These points would indicate that : — 



{a) The preliminary liquefaction should be conducted in a 

 closed chamber : 



(6) The amines must be removed by a nitrous or other 

 oxidation in the second part of the process, before reaching 

 the nitric organisms. 



4. The Formation of Organic Acids and Fermentation of their 

 Salts. — In the resolution of complex organic molecules a 

 number of organic acids are set free, and combine with any 



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