BATCH TYPE SEWAGE TREATMENT DEVICE AND INSTRUMENT FOR MEASURING CONCENTRATION OF ACTIVATED SLUDGE

摘要

PURPOSE:To stabilize and improve treatment capacity by measuring the concn. of suspending activated sludge at the prescribed set timing at the end of an aeration stirring stage, calculating a sludge discharge rate in such a manner that a target concn. is obtd. from the result of the measurement and controlling sludge discharge pumps. CONSTITUTION:The sewage 15 is supplied from a sewage adjusting tank 1 by a supply pump 4 through a selector valve 16 to a batch tank 2A or 2B from a supply path 17A or 17B. The sewage is anaerobically stirred by operation of the impellers of stirrers 5A, 5B. Further, the sewage is aerobically stirred by injection of the air from a discharge port. Next, a settling process is started and the supernatant water in the respective batch tanks 2A, 2B is discharged by discharging devices 6A, 6B in a succeeding discharge process. The excess sludge is discharged by the discharge pumps 7A, 7B to a sludge storage tank 3. At this time, the concn. of the suspending activated sludge at a prescribed set timing at the time of ending of the aeration stirring process is measured and the sludge discharge rate is calculated from the deviation from the target concn. The respective pumps 7a, 7b are then controlled.