GB104187A - Improvements in and connected with the Purification of Sewage and other Liquids. - Google Patents

Abstract

104,187. Jones, W., and Jones & Attwood. July 11, 1916. Aerating.-In treating sewage and other impure liquids by aeration in presence of bacterial sludge in tanks through which the sewage circulates, the sludge is transferred bv air-lifts from one part of the tank and is mixed with the sewage in another part, the transfer preferably taking place from the outlet side to the inlet side. An elongated rectangular tank, shown in section in Fig. 3, is divided by a longitudinal partition 10 and has transverse air-diffusers 2 separated by ridges 5. Sewage passes along the side a of the tank and returns along the side b. Sludge which accumulates in the return side above the level of the ridges 5 passes over a weir 27 and passage 24 and is raised by an air-lift 25 into the entry side a. The tank is provided with alternate transverse curtain walls and sunken weirs, under and over which the sewage flows. The discharge end of the side b has no air-diffusers, in order that the whole of the sludge may deposit before discharge of the effluent. The sewage may pass in succession through a series of tanks 1, Fig. 5, each divided by a partition 10. The sewage passes from the outlet side of each tank over a weir 15 into the next tank, and the sludge which passes over weirs 35 is raised by air-lifts 33 from the outlet side to the inlet side. The further quantity of sludge may be raised from the tanks by air-lifts 33<a> into a conduit 38, from which it is discharged into any of the tanks, or into an aerating-tank 37, which discharges over a weir 34 into the crude sewage. In a tank having a number of longitudinal partitions to form a series of parallel channels, the channels are provided at the outlet ends with weirs over which the upper layers of sewage pass, and with air-lifts which transfer the sludge into the preceding channel.