| 摘要 |
<p>PURPOSE:Not to give out the amount of return sludge and to prevent the destruction of siphon, by attaching the valve on siphon tube drawing out activated sludge from the sludge precipitation pool to the sludge pit and controlling the removal amount of the sludge at the sewage treating apparatus by the activated sludge. CONSTITUTION:The activated sludge 3 collected at the bottom of the precipitation pool 1 of the sewage activated sludge treatment apparatus, is connected with the sludge pit 6 by the siphon tube 7 provided with the valve 8 and a constant amount of the sludge is returned to the air exposure vessel and then, another part is thrown away as surplus sludge. On this occasion, water level of the pit 6 is detected by the detector 11 and deflection of the above output and the sludge pit water level target value 13, is found by the comparison circuit 12. Functioning command of the valve 8 is given to the vale control circuit 16 when the water level of the pit 6 is risen by drawing out excess sludge and is exceeded set point of the discrimination circuit 15. The motor 9 is operated to shut the valve 8 by the functioning command and removal of the sludge from the pool 1 to the pit 6 is stopped. Then, the water level of the pit 6 is risen and destruction of siphon is prevented and then, operation is carried out smoothly.</p> |
