METHOD FOR CONTROLLING OPERATION OF INTERMITTENT AERATION-TYPE ACTIVATED-SLUDGE PROCESS

PURPOSE:To eliminate a sensor for control and to operate and control an intermittent aeration method exhibiting stable denitrification and dephosphorization efficiencies only with setting of time by a timer by performing control of aeration and stirring time of the first and the second aeration tanks wholly by means of the timer. CONSTITUTION:After nitrification and absorption of phosphorus are performed under a condition with a dissolved oxygen concn. of 2-3mg/l by setting 30min of the aeration time Ta1 of the first aeration tank 2a, and 70min of the aeration time Ta2 of the second aeration tank 2b, the process is shifted to a stirring process and denitrification and discharge of phosphorus are performed. When the time Ts of one anaerobic-aerobic cycle, 120min, passes through, control by using a timer is performed so as to return both the first and the second aeration tank 2a and 2b to the aeration condition. The aeration time ratio (r) is obtd. by an equation wherein the vol. of the first aeration tank 2a is V1 the vol. of the second aeration tank 2b is V2, the sludge retaining time is (n) days, the specific proliferation rate is mu and Ta1 and Ta2 are set to be (r)>1/(n.u) and Ta1