| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress rise of water areal load in a precipitation tank and to discharge treated water of good quality from the precipitation tank even in the case of abnormal flooding in an oxidation ditch(OD) type waste water treating plant. SOLUTION: The waste water treating plant is provided with a flow meter 3 which measures and outputs quantity of raw water per hour supplied from a raw water tank 10 to a ditch 11 and a computing element 1 accepting output of the flow meter 3 and the supply amount of the raw water per hour in a day supplied from the raw water tank 10 to the ditch 11 with an ordinary supplying pattern is stored in the computing element 1. Then, the computing element 1 compares real supply amount of the raw water per hour to the ditch 11 outputted from the flow meter 3 with the stored amount thereof per hour at the same time. When the real supply amount thereof exceeds the stored amount, the computing element 1 takes a posture for monitoring abnormality, a weir board 13 in the ditch 11 is lowered to lower water level in the ditch 11 by making treated water in the ditch 11 overflow to the precipitation tank. In such a manner, rapid increase of flow rate load to the precipitation tank is prevented and outflow of sludge into the treated water is prevented.</p> |
