| 摘要 |
<p>PURPOSE:To obtain treated water of stable quality by a controlling method in which the target value of floating solids is changed proportionally to the organic substance load of incoming sewage, and when the organic substance load is abnormally high, the target value is controlled to less than the upper limit value. CONSTITUTION:Sewage is flowed through the sewage inlet path 1 into the aeration tank 2 and then sent through the polluted water outlet path 3 to the final sedimentation basin 4 from which treated water is overflowed through the overflow path 5 and also sediment sludge is sent back to the aeration tank 2 while be pressurized by the return sludge pump 7 through the sludge pipe 6 and also while being regulated its flow rate by the regultaing valve 8. The incoming sewage amount is put in the arithmetic controller 15 by the detector 9, the total organic carbon amount is by the total carbon amount detector 10, the floating solid in the aeration tank 2 is by the detector 11, the return sludge amount is by the detector 12, and the return sludge concentration is by the detector 13. The arithmetic controller 14 performs a calculation on these information and then gives the target value of return sludge amount to the controller 15 from which a control output is sent to the return sludge pump 7 and the control valve 8 to realize the target value of return sludge amount.</p> |
