Land Treatment of Sewage. 



hours. Part of the Sludge (about 35 tons, wet, 

 weekly) is sold and part used to fill up holes in a 

 disused brickyard on the farm. The Analyset, both 

 chemical and bacteriological, of the sewage will be 



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

 in twenty-four hours is for soil 0'073, subsoil 0020; 

 and dissolved by water saturated with carbonic acid 

 in forty-eight hours, for soil, 0382, subsoil 0076. 



MECHANICAL ANALYSIS. 



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



Sand (0-25 -0-5 mm.) -silt (0-05 - 0-01 mm.) 



Dust (O'Ol mm. - settling from water within 24 hours) - 



dilute nitric acid) 



Loss on ignition (separate determination) 



clay (still finer precipitated by 



415 

 52-30 



25-29 

 1203 



93-77 



found at the end of this section compared with those 

 of the effluent and of the stream. 



Aoreage, 

 Population, &o. 



Soil 

 and SubMll. 



The Soil, stiff and heavy, is 

 from 6 in. to 10 in. deep, and has 

 been lightened in one or two parts 

 by the digging in of ashes. The Subsoil is also stifE 

 and heavy, partaking more of the nature of a brick- 

 earth, resting on the London clay. The Under- 

 drainage extends over about 25 acres. The drains 

 are 4-in. and 6-in. socketted pipes, and are laid at an 

 average depth of about 2 ft. They are about 12 yds. 

 apart, and were put in to assist waterlogged plots to 

 dry. Subsoil Water and Floods. — There is no subsoil 

 water on the farm, and the land is not liable to floods. 

 The Mechanical Analysis given above shows the 



The total area of the farm is 

 191 acres, and of this 152 acres 

 are available for sewage treat- 

 ment. The average area under irrigation at one 

 time is 51 acres; the population served is 21,000, 

 which works out at 138 persons per irrigable acre, 

 or 415 persons per acre for the average area irrigated. 

 The normal dry-weather flow is 285 gallons per 

 head per diem. The amount treated per acre for 

 twenty-four hours at the normal rate of flow is 

 12,000 gallons on the average area irrigated, equal 

 to 4,000 gallons on the whole irrigable area. 



Treatment. — The sewage is 

 treated on separate plots, either 

 two, three or four times, being 

 run over the surface of the land in a thin sheet. 



Treatment 

 and Cropping. 



percentage composition of the ignited soil. The 

 subsoil was not analysed. 



The approximate number of particles in 1 gramme 

 was 1,448,196,680, and in 1 c.c. 1,772,14<4,510. 



picked up in a carrier at the bottom of the plot and 

 passed over other plots in a similar manner. The 

 effluents from the drained area are brought to the 

 surface lower down the farm and re-treated. The 



56 



