TREATMENT OF ORGANIC WASTE WATER

摘要

PROBLEM TO BE SOLVED: To stably treat org. waste water even if the properties of feed water are rapidly changed in the treatment of org. waste water by a two-phase activated sludge method by suppressing the variation in the concn. of org. pollutants shown by BOD in the water introduced into a treating tank. SOLUTION: Two-phase activated sludge treatment is conducted in a first bacteriological treating tank and a second treating tank for sessile protozoa treatment and activated sludge treatment. A regulation tank is provided before the first treating tank to suppress the variation in the feed water concn. of the water to be treated and to be introduced into the first treating tank. The one used in biological treatment and provided with an air or oxygen-permeable aeration pipe is used as the first treating tank, and a standard aeration tank a fixed-bed or roating-disk aeration tank or the like are used as the second treating tank. Besides, the feed rate of the waste water to the first treating tank is so selected that the treating time is longer than the maximum specific growth rate of protozoa to restrict the appearance of the protozoa.