| 摘要 |
<p>PURPOSE:Outputs from MLSS concentration meters in an aeration tank are each calculated to thereby maintain the mean time of active aludge stay and the total quantity of sludge in the aeration tank and fianl sedimentation basin. CONSTITUTION:The 4th calculator 4 provides a quantity of newly formed sludge by operating each input from the 1st calculator 9 on sludge quantity, from the flow meter 14 on flow rate of incoming sewage, from the concentration meter 15 on concentration of organic material, and from the concentation meter 16 on concentration of SS. The 5th calculator 18 provides the average stay time from the information on the quantity of sludge formed during several prior points to the present time, and on the quantity of surplus sludge to be extracted. This value of average stay time, the total sludge quantity, a load for quantity of sludge to be extracted, and signal from the target setter 10 are operated by the 6th calculator 19, which provides instruction values for the surplus sludge to be extracted in order to maintain constant values of average sludge stay time and the total sludge quantity during the following several steps. This instruction and the concentration of surplus sludge are operated by the 7th calculator 20, which then provides thr flow rate for extraction, and controls the flow rate adjuster 4 for extracting surplus sludge.</p> |
