124 TOWN SEWAGE, AND ITS 



TOWN SEWAGE, AND ITS APPLICATIOX TO AGRICULTURE. 



By David Robie, Bedford. 



[Premium — Ten Sovereigns. ] 



With the increase of urban populations, and the introduction 

 of additional water, came the urgency for the discharge of that 

 water, and its accompanying refuse matters, in compliance with 

 the requirements of sanitary law. Pecuniary considerations had 

 to give way, for the health of man was the primary considera- 

 tion ; and the application of that sewage to manure the land 

 was a secondary, but still an important matter. A select 

 committee of the House of Commons investigated the subject in 

 1862, and sewage irrigation was mucli discussed before and 

 since that time in agricultural newspapers and other publica- 

 tions. Extreme opinions were expressed as to its agricultural 

 value, for some said it was worth 20s. per head per annum, and 

 fanciful notions were imbibed as to its produce on irrigated 

 farms. Professor Anderson, in a lecture delivered under the 

 auspices of the Highland and Agricultural Society of Scotland 

 in 1864, estimated the refuse of each head of the population at 

 6s. per annum. Sir J. B. Lawes of Eothamsted states, that 

 when the human excrements are deprived of water, they 

 amount to about 46 lbs. per head per annum. But when it is 

 considered that about 30 tons of water is supplied annually to 

 each urban resident, we realise in a great measure the enormous 

 quantity of water with which the human excreta is charged. 

 L)r Voelcker, in treating on the value of sewage, states that there 

 were about seven grains of ammonia in the gallon, which is the 

 most valuable constituent, and the amount of the other manurial 

 substances — mostly phosphoric acid and potash — rise and fall 

 with it. It is hardly necessary to explain that sewage differs 

 widely in character, according to the amount of water with 

 which it is charged. 



There are now said to be about one hundred towns which 

 have dealt with their sewage, and those have been most suc- 

 cessful who have sent it directly to land. Wasteful chemical 

 processes, settling and precipitating tanks, filter beds, &c., have 

 iDeen brought more or less into use, but generally with indifferent 

 success, and at a great cost. Some of these plans have been 

 abandoned, and recourse had to irrigation, which is really the 

 most economical way of disposing of sewage in an innocuous 

 manner. The costs, however, have been very heavy, and taking 

 into account the initiatory outlay, and the rents, rates, and 

 labour, it is obvious that sewage farms do not pay. It is indeed 

 argued, that the expense of scavenging is saved by the system of 



