| 摘要 |
<p>PURPOSE:To properly hold an activated sludge holding amount, in the control of the titled plant, by controlling the withdrawal amount of excessive sludge on the basis of the target value of the total holding amount of activated sludge calculated by setting the oxidation power of activated sludge as an index. CONSTITUTION:Sewage enters an aeration tank 1 from a pipeline A where purified by activated sludge and the purified sewage enters a precipitation basin 5 while supernatant water is taken out. The greater part of sludge precipitated in the basin 5 is returned to the tank 1 and the remainder is withdrawn as excessive sludge from a pipeline C. Air is sent into the tank 1 by a blower 9. Herein, signals of an inflow sewage flow amount, an org. substance concn., a floated substance concn., a return sludge flow amount, the concn. thereof and a withdraw sludge flow amount QW are inputted to a simulator 11. From sludge amount signals of the tank 1 and the basin 5 and the sludge state signal at each part in the tank 1 operated herein, operation parts 12, 16 respectively calculate the total sludge holding amount WT of the tank 1 and the basin 5 and the oxidation power of the sludge in the tank 1. An operation part 17 calculates the average value of oxidation power while an operation part 18 compares the same with an objective oxidation power value to calculate a correction amount and controls the amount QW so as to allow the amount WT to coincide with the target value obtained by correcting the set value on the basis of the aforementioned correction amount.</p> |
