| 摘要 |
<p>PURPOSE:To eliminate and prevent clogging by calculating overall oxygen transfer coefficient based on detected values of respiration velocity and dissolved oxygen concentration, increasing temporarily air feed rate when the values are small to remove sludge deposited in a diffusing hole of a diffuser. CONSTITUTION:A respiration velocity detecting means 5 mounted on a treatment tank 1 incorporates a dissolved oxygen concentration meter, whereby respiration velocity and dissolved oxygen concentration are outputted to a control unit 6 to calculate overall oxygen transfer coefficient which represents efficiency of diffusion. The unit 6 controls parts of an activated sludge treatment system such as control of air feed rate, etc. A control valve drive unit 7 drives a control valve 4 based on command from the unit 6. Main cause of lowering of diffusion efficiency is clogging of a diffusing plate 2. Therefore, when lowering of diffusion efficiency occurs, the control valve 4 is actuated to double the rate of air feed temporarily. As a result, clogging of the diffuser can be eliminated before excessive clogging takes place, so that stable activated sludge treatment can be accomplished.</p> |
