Land Treatment of Sewagre. 



being added at a rate, first of all, of 15 grains per 

 gallon ; subsequently this amount was reduced to 

 11, 10, and finally 8 grains per gallon. This treat- 



The Mechanical Analysis shows the following 

 percentage composition of the ignited soil and sub- 

 soil : — 



ment was, however, eventually abandoned in 

 November, 1898, as it was found that the farm was 

 rapidly being choked for filtration purposes. The 

 Subsoil is a compact stratum of gravel and sand 

 overlying the gault clay, which is found at a depth 

 of 7 ft. to 12 ft. below the surface. About 2 ft. to 

 2ft. Gin. from the surface soil a vein of sand, im- 

 pregnated with iron, occurs in parts. Under-drain- 

 age. — The entire farm is under-drained, and the 

 pipes are laid at a depth of from 3 ft. 6 in. to 6 ft., 

 and about 50 ft. apart. On plot 4 the drains are 

 only 16 ft. 6 in. distant from each other, and on 

 plot 11 (3^ acres) 14 ft., with a view of increasing 

 the rate of filtration. The feeder drains are ordinary 

 4-in. butt agricultural pipes, laid herring - bone 

 chiefly, and are connected np to 12-in., 18-in. and 

 21-in. socketted stoneware master-drains, which in 

 turn flow into a 24-in. main effluent drain. Subsoil 



The approximate number of particles in 1 gramme 

 is for soil 614,122,600, subsoil 176,087,960 ; and in 

 1 c.c. for soil 880,665,516, subsoil 3-20,657,693. 



The Lime (parts per 100,000) dissolved by 

 water in twenty-four hours is for soil 0085, 

 subsoil 0-058 ; and dissolved by water saturated 

 with carbonic acid in forty-eight hours, for soil 

 0-530, subsoil 0-582. 



Acreage, 

 Population, &o. 



The total area of the farm is 

 102"5 acies, and of this 74 acres 

 are available for sewage treat- 

 ment. The average area under irrigation at one time 

 is 18'5 acres ; the population served is 50,000, which 

 works out at 676 persons per irrigable acre, or 2,703 

 persons per acre for the average area irrigated. The 

 normal dry- weather flow is 45 gallons per head per 

 diem. The amount treated per acre for twenty-four 



Water and Floods. — The subsoil water in dry 

 weather lies at a depth of 6 ft. to 7 ft. from the 

 ground level. The farm is not liable to floods. 



honrs at the normal rate of flow is 121,600 gallons 

 on the average area irrigated, equal to 30,400 gallons 

 on the whole irrigable area. 



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