| 摘要 |
<p>PURPOSE:To lower running cost, by automatically controlling an amount of necessary air in an aeration vessel on the bases of amounts of dissolved oxygen and suspensoid mass in the final aerating zone of the aeration vessel. CONSTITUTION:An active sludge processing apparatus comprises a raw water reservoir 1, a raw water pump 2, an aeration vessel 3, a sedimentation vessel 4, a returned sludge pump 5 and air compressors 6, 7. The vessel 3 is provided with baffle walls 14. Automatic aeration-controlling means is arranged in the final aerating zone of the vessel 3. A mixed solution after aeration is s ucked up by a pump 10. An amount of residual oxygen in the solution after consumption is detected by a sensor 9 in a conduit. The detected value is fed to a controller 12. On the other hand, when the amount of residual dissolved oxygen detected by a sensor 8 at the inlet side of the final aerating zone lowers to a level of 1-4mg/l or so, the compressor 6 is driven by the controller 12. The controller 12 calculates an oxygen consumption rate from a difference between the values detected by the sensors 8 and 9 and a value detected by an active sludge amount sensor 13 at the same position of the sensor 8. When the oxygen consumption rate reaches the amount of endogenous respiration of the active sludge, the compressor 6 is stopped.</p> |
