| 摘要 |
PURPOSE:To save electrical energy for a blower upon the control of a dissolve oxygen (DO) value by measuring the concentration of inflow effluent with the use of a concentration meter so that the airflow rate of the blower may be decreased to a value lower than the DO value of an deaeration tank when the measured concentration is lower than a regulated value. CONSTITUTION:A concentration meter is disposed in the inlet part of a first sedimentation besin 15 and the delay of the lapse time of effluent flowing through the first sedimentation basin 15 is set on a time delay part 17. The correction for DO control due to the concentration is made in a concentration operating part 18. The value of FDO determined in a DO control part 3 is decreased by reducing a proportional constant when the concentration is lower than a regulated value D1, so that the target value FT of a total air flow rate is decreased correspondingly, thereby electrical power for a blower is duly reduced. |
