Land Treatment of Sewag^e. 



Soil 

 and Subsoil. 



The Soil varies in places, the 

 surface soil consisting of 8 in. to 

 10 in. of black porous soil mixed 

 with and lying upon a layer of deeomposed peat 

 4 in. to 7 in. deep. The Subsoil is fine, white sand 

 and gravel. About one-half of the farm was 

 formerly pure bog-land (Carrington Moss), the re- 

 maining half or southern portion of the farm is 

 of a sandier nature. The actual peat land is not 

 irrigated. There is a large quantity of iron in 

 the soil, and a pan of some 3 in. to 6 in. in thick- 

 ness occurs in places. Under-drainage. — The irri- 

 gated area is under-drained, 4 yds. to 5 yds. apart, 

 with ordinary 4-in. pipes about 3 ft. 6 in. to 4 ft. 

 deep, laid parallel and joining 9-in. stoneware 

 socketted master-drains, which are connected up 

 to brick effluent manholes. Subsoil Water and 

 Floods. — There appears to be a little subsoil water 

 present in the drains in wet weather. The land is 

 not liable to floods. 



The Mechanical Analysis shows the following 

 percentage composition of the ignited soil. The 

 subsoil was not analysed. 



Treatment 

 and Cropping. 



per acre for twenty-four hours at the normal rate 

 of flow is 46,000 gallons on the average area irri- 

 gated, equal to 23,000 gallons on the whole irrigable 

 area. 



Treatment. — From the settling 

 tank the sewage passes along a 

 main carrier ; closed pipe carriers 

 are also used. The bricks in the sides of the main 

 carrier have perished badly with the frost, and 

 grease, kc, accumulates against the sides and 

 hinders the cleansing of the carriers. From the 

 main carriers the sewage either flows directly on 

 to the land or first into spade-formed subsidiary 

 carriers, as the case may be. Owing to the insuf- 

 ficient capacity of the settling tank, sewage is 

 usually run on to a plot of land banked round so as 

 to form a lagoon of 2 or 3 acres, and sufficiently 

 large to contain about one day's sewage flow. The 

 suspended matter left in the settled sewage after 

 passing through the tank is almost entirely de- 

 posited here and the surface water drawn off at 

 the foot of the plot, either direct or by earthen 

 carriers, to the plots of land to be irrigated. The 



MECHANICAL ANALYSIS. 



Fine gravel (above 2 mm.)— medium sand (above 0*25 mm.) 



Sand (0-25 - 005 mm.) - silt (0-05 - 0-01 mm.) 



Duat (O'Ol — settling from water within twenty-four hours)— clay (still finer — precipitated 



by dilute nitric acid) 



Loss on ignition (separate determination) 



14-87 

 49-66 



9-77 

 23-24 



97-54 



The approximate number of particles in 1 gramme 

 is 1,284,209,670, and in 1 c.c, 1,101,862,900. 



The Lime (parts per 100,000) dissolved by water 

 in twenty - four hours is, for soil, 0-045, subsoil 

 0'016, and dissolved by water saturated with car- 

 bonic acid in forty-eight hours, for soil 0'197, sub- 

 soil 0068. 



The total area of the farm is 

 Acreage, 



Population, &o. 



75-5 acres, and of this 35 acres 



are available for sewage treat- 

 ment. The average area under irrigation at one 

 time is 17-5 acres; the population served is 18,000 

 (Altrincham 17,500, and Dunham Massey 500), 

 which works out at 514 persons per irrigable acre, 

 or 1,028 persons per acre for the average area irri- 

 gated. The normal dry-weather flow is 44-4 gal- 

 lons per head per diem. The amount treated 



lagoon method was found not to be practicable 

 in hot weather, the scum rising from the bottom 

 of the lagoon in floating masses and creating a 

 nuisance. When the lagoon is first filled a por- 

 tion of the impounded sewage filters through the 

 soil to the under-drains, but the land soon silts up 

 and will not pass any water through. After a 

 lagoon has been used for three or four months 

 it is dried, the sludge (about 3 in.) is ploughed in 

 and a fresh lagoon made. The sewage and lagoon 

 liquor is generally run on to the same plots in- 

 termittently for periods varying from fourteen to 

 twenty-eight days, being turned on to the plots 

 continuously for about twelve hours. In winter 

 the sewage is sometimes applied to the land both 

 night and day, without intermission. At such 

 times there is considerable risk of the frost raising 



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