CAMBRIDGE. 



HISTORY. 



The farm is of recent date, and beyond the 

 reference to lime treatment (see Soil) there is 

 nothing noteworthy to record. In " Sewage Treat- 

 ment and Disposal," by Thomas Wardle (F1893), 

 reference is made to the suggestion that 640 acres 

 or so at Shesterton Fen should be laid out for a 

 sewage farm. Although the British Medical Journal 

 thought it would be a good plan, the author did not 

 agree (p. 120). It will be seen that the scheme was 

 abandoned. 



REPORTS TO THE ROYAL COMMISSION. 



Conservancy. — There are very 

 The Sewage, few privies, and the night soil 

 from these is taken by farmers. 

 Separate or Combined. — The town is only partially 

 on the separate system. All water from back-yards 

 and back parts of roofs goes to the foul- water 

 sewers. Domestic. — The sewage is practically 

 domestic, but there is a small quantity of effluent 

 from two breweries. Subsoil Water. — In normal 

 dry weather the subsoil water amounts to about 

 40 per cent (say 900,000 gallons per diem), due to 

 faulty sewers. After heavy storms the sewage flow 

 at times does not return to normal for some days 

 in consequence of the excess of subsoil water finding 

 its way into the sewers. The normal Dry-weather 

 Flow, including subsoil water, is 2,250,000 gallons 

 per diem, and the Storm Flow has reached 5,000,000 

 gallons for twenty-four hours. The storm water is 

 now treated on coarse clinker beds at the pumping 

 station, and, consequently, the amount received at 

 the farm during storms is not greatly in excess of 

 the normal flow. The Water Supply is about 

 24 gallons per head, obtained from wells in the 

 chalk marl, greensand and the chalk. The Rainfall 

 averages 21 in. per annum, and the Drainage Area 

 of districts sewered is 1,500 acres. Flushing. — The 

 sewers are flushed quarterly with waterworks water. 

 Stay in Sewers. — The sewage takes about one hour 

 to flow from the centre of Cambridge to the pumping 



station, a Distance of 1| miles. Sewer Capacity. — 

 The whole of the sewage gravitates to the pumps 

 through a 4 ft. 3 in. by 2 ft. 10 in. sewer, laid at a 

 gradient of about 1 in 870 ; its theoretical capacity, 

 running full, being 2,060 c.f .m. There are five Storm 

 Overflows discharging into the Cam on either side of 

 the pumping station ; they have only once come into 

 operation during the last 8 years ; the sewage has 

 to rise about 30 ft. in the pump well before an over- 

 flow takes place, and this would back up the water 

 in the outfall sewer, flooding some portions of the 

 town. Screens. — The sewage passes through a cage 

 screen before reaching the pump well. Pumps. — 

 From the pumping station the sewage is pumped to 

 the farm in a 24-in. cast-iron rising main 2 miles 

 long. The lift is 44 ft., and the sewage takes about 

 40 minutes to reach the farm. There is only one 

 Settling Tank, 61 ft. by 39 ft. by about 3 ft. average 

 depth, with a capacity of about 45,000 gallons. It 

 is worked on the continuous system and is cleaned 

 out twice a week, the operation taking but a short 

 time. The Stay in Tank is only about 30 minutes. 

 The Screenings are burnt in the destructor, which 

 is used for disposing of the town's refuse and at the 

 same time for supplying steam for pumping pur- 

 poses. The Sludge is run into oblong sludge beds 

 lying alongside the carrier embankments ; it is subse- 

 quently dug in. It is also passed over other portions 

 of the land where wanted. Approximately 35 tons 

 of wet sludge are produced a week, but the quantity 

 varies considerably. A reference to Buried Sludge 

 will be made hereafter. The Analyses, both chemical 

 and bacteriological, of the sewage will be found at 

 the end of this section compared with those of the 

 effluent and of the stream. 



soil 

 and Subsoil. 



The iSot'Z consists of 12 in. to 15 in. 

 of sandy loam. On plot 4 (nearly 

 5 acres) 100 tons of fine destructor 

 ash have been ploughed in on account of the quan- 

 tity of sludge used. The lime process was employed 

 for two and a half years (commencing 1895), lime 



23 



