| 摘要 |
<p><PICT:0973962/C1/1> A plant for aerating sewage has aeration tanks 1, 2, 3, a settling tank 6 and a sludge tank 7 each consisting of a receptacle, with a prismatic or cylindrical body portion and a bottom portion of which is of inverted pyramidal or conical form. The air diffusing devices 24 consist of a hollow pyramid or cone having perforated sides, arranged with its point downwards in the lowest part of each aeration tank and the sludge tank. Sludge may return to first aeration tank by pipe 28. The sewage may pass through a rag and grit removal chamber before entering the first aeration tank, in which latter a strainer is provided to receive the entering sewage. The rate of flow of sewage through the plant is controlled by a calibrated orifice at the entrance to the settling tank or each settling tank, the flow from one aeration tank to the next and between the sludge tank and first aeration tank being determined by the liquid levels in the respective tanks and without the aid of further regulating valves.</p> |
