34 BOAED OF AGEICULTURE. 



delay and litigation, the city bought 120 acres of land, and 

 on the advice of an eno^ineer constructed a new reservoir of 

 deposit, where they treat the sewage with thirteen tons of 

 lime each day. This clarifies the water to a certain extent 

 by causing a deposit of about 300 tons per day, which is 

 carted out and buried on the land. 



It has been an easy matter to separate material in suspen- 

 sion from drain water by filtration, but as this represents 

 only about one-seventh part of the value of sewage for 

 fertilizing purposes, the process, though simple, has never 

 proved remunerative, and chemists have been employed to 

 suggest agents which would precipitate the soluble matter, 

 which represents six-sevenths of the value. Lime has been 

 employed at Tottenham, Blackburn and Leicester, but the 

 Royal Commissioners report of each a failure, inasmuch as 

 the drain water, after being thus treated, contains a large 

 amount of putrescible matter. 



Treatment by Lime and Chloride of Iron at Northampton, 



England. 



To 250,000 gallons of sewage is added about 100 quarts 

 of lime and six quarts of chloride of iron, which are thor- 

 oughly mixed, and afterwards passed, by upward filtration, 

 through a layer of calcinated iron eight inches thick. The 

 ■water comes out without color or odor, and is then allowed 

 to flow into the river. At first there was no complaint, 

 notwithstanding the presence of a large amount of putres- 

 cible matter, but later the river became offensive, and the 

 court enjoined the discharge there. 



The Complicated ''ABC Method of Sillar" 

 produces a valuable fertilizer. But the residuary water still 

 contains putrescible matter, and notably more ammonia 

 than the sewage before being treated. 



Precipitation hj Chemical Mean<i at Coventry, England. 



Population 40,000. Five thousand water-closets are con- 

 nected with the sewers, which discharged 2,289,000 gallons 

 of sewage in the river Sherburne. Complaint and litigation 

 was the result. A reservoir of deposit was constructed. 



