MLSS AUTOMATIC CONTROLLING DEVICE OF SEWAGE TREATING EQUIPMENT PROVIDED WITH AERATION TANK

摘要

PROBLEM TO BE SOLVED: To calculate a target MLSS value (set MLSS) of an aeration tank in accordance with the variation in the amount of influent water, to control a flow rate of return sludge so as to keep the calculated target MLSS value and also to automatically decide the time opening a surplus sludge valve drawing the surplus sludge. SOLUTION: A set MLSS is calculated based on the amount of influent water. When the set MLSS > a true MLSS, the flow rate of return sludge is calculated and an inverter of a sludge return pump is controlled. When the set MLSS < the true MLSS, the sludge return pump is stopped. The time opening a surplus sludge valve is calculated and the surplus sludge valve is opened during a prescribed opening time and also the sludge is discharged by operating a sludge drawing pump.