AGRICULTURAL VALUE OF EFFLUENTS 331 



Peruvian guano. Tidy tabulates the components of urine and 

 faeces as follows^ : — 



The Royal Commission of 1858-1865 concluded after ex- 

 haustive experiments that sludge contained only one-eighth of 

 the value of the sewage from an agricultural point of view^, and 

 thus encouraged the principle of sewage farms, with direct 

 application to the land. The chief causes of failure were (i) the 

 very large volume of sewage that had to be continuously dealt 

 with, (2) its property of fouling or clogging, (3) the relatively 

 small amount of important manurial ingredients like phos- 

 phates, potash, and nitrogen it contained in proportion to the 

 quantity of water, (4) the unsuitable form in which the organic 

 nitrogen existed. The last difficulty suggested that if the liquid 

 was properly prepared or matured by a fermentation process 

 analogous to that by which a farmer "ripens" manure, this 

 nitrogen might be more readily utilized by plants. Mr. Davies^ 

 held out great hopes in this direction, while Mr. Daniel Pidgeon^ 

 dealing with the bacterial purification of sewage, showed 

 forcibly the practical value of highly nitrified effluents for all 

 kinds of cultivation. 



Scott-Moncrieff^ pointed out that a go% nitrification of the 

 total nitrogen in ordinary sewage would, based on the cost of 

 nitrate of soda, amount to ;f 14,000,000 per annum on the whole 

 sewage of the United Kingdom, a saving which nearly recovers 

 the waste mentioned by Sir W. Crookes. These highly 

 nitrated effluents also contain plant-food in nearly ideal pro- 



1 Journal of the Society of Arts, Oct. 8, 1886. See also " Collection and Utiliza- 

 tion of Excreta," James Ashton, Inst. San. Engineers, Wolverhampton Meeting, 

 1903. 



- Joiirn. R. Agric. Soc, Oct., 1899. 

 * Southampton Sanitary Congress, iJ 



3 Ibid. 

 J. San. Inst., vol. xx., part iv. 



