| 摘要 |
<p>PURPOSE:To control a sludge turbidity under a stable and good condition for a long period, by measuring the sludge turbidity of a mixed solution in each of a sludge reservation zone and a mixing zone of an aeration vessle, and extracting a sludge from a precipitation vessel to outside the system in case where the difference between the two measured sludge turbidity is higher than a preset value. CONSTITUTION:With the increase of sludge proliferation, a sludge amount throughout the process gradually increases. The increased sludge amount is accumulated mainly in a zone A, but not in a zone B where a mixed liquor suspended solid consistency (MLSS) is controlled. As a result, MLSS in the zone A rises, a period during which the difference between MLSSs in the zone A and the zone B is higher than a preset value at a device 17 is extended, and the operating period of an excessive sludge pump is extended. Consequently, both of the MLSS values and the sludge amounts are still balanced properly, and the MLSS values are controlled satisfactorily. In case where the sludge proliferation is reduced, the MLSS difference between the zone A and the zone B is reduced, and the extraction amount of the excessive sludge is also reduced. Consequently, the MLSS values and the whole sludge amount are still balanced properly, and the MLSS values are controlled satisfactorily also.</p> |
