DISCARDING METHOD FOR SLUDGE IN ACTIVATED SLUDGE METHOD WASTE WATER TREATING SYSTEM

摘要

PURPOSE:To inprove the quality of treated water, in the treatment of waste water using activated sludge for treating BOD constituents and ammoniacal nitrogen, by considering discarded sludge to the total amount of retained sludge to be a function of liq. temp. of an aeration tank to activate microorganisms in the system. CONSTITUTION:In the treatment of waste water by an activated sludge method for removing BOD constituents and converting ammoniacal nitrogen into nitrate nitrogen, the ratio of the amount of excess sludge discarded per day to the amount of sludge retained is adjusted to the 0.007t-0.025-0.004t-0.03 range when liq. temp. of an aeration tank is t deg.C. Thus, the operational conditions of the system are maintained well, preventing deterioration of bacteria and activating microorganisms in the system, whereby the removal of BOD constituents and the conversion of ammoniacal nitrogen into nitrate nitrogen are performed stably to improve the quality of treated water.