| 摘要 |
<p>PURPOSE:To certainly control the formation and stop of a siphon stream when supernatant water flows out of a flooding pipe, in a batchwise activated sludge treatment tank having a water gathering trough followable to the variation of a water level, by connecting an exhaust piping system, a siphon break piping system and a control device to said water gathering trough. CONSTITUTION:An aerator 5 and the flooding pipe 9 connected to an extensible drain pipe 7 are provided to a frame 4 equipped with a float 3 rising and falling so as to follow the variation of the water level in a treatment tank 1. Further, the flooding pipe 9 is covered with a cap case-shape water gathering trough 6 so that the whole of an aeration device 2 stably floats on the surface of water even when the water level is varied. A drain control circuit 12 (exhaust piping system 20, siphon break piping system 30) for reducing the pressure in the water gathering trough 6 to raise the water level and discharging water from the flooding pipe 9 as a siphon stream is connected to the water gathering trough 6. In this constitution, after the sedimentation of a sludge component, the exhaust piping system 20 is operated to allow supernatant water to flow out from the upper end of the flooding pipe 9 and, when the water level falls to a predetermined one, siphoning action is broken to stop drain.</p> |
