ACTIVATED SLUDGE PROCESS EQUIPMENT AND METHOD FOR CONTROLLING RETURN SLUDGE

摘要

PROBLEM TO BE SOLVED: To provide a method for monitoring fluctuation of load of org. substances in a raw water by a simple method and adjusting amt. of return sludge to be commensurate with the amt. of fluctuation and an apparatus for it. SOLUTION: A part of a raw water is taken out and is satd. with dissolved oxygen in a dissolved oxygen saturation tank 5 and is transferred to a dissolved oxygen measuring tank 6. A part of sludge from an aeration tank 1 is also distributed by a definite amt. in a distribution tank 4 and is transferred to the measuring tank 6, where change in concn. of the dissolved oxygen is measured. From the results obtd., amt. of return sludge being commensurate with concn. of org. substances in the raw water is estimated by means of an apparatus 8 for estimating amt. of return sludge and based on it, the amt. of return sludge from a precipitation tank 2 is controlled.