REFORMATION OF ACTIVE SLUDGE, WHICH HAS FORMED MOLD FUNGUS-TYPE OR NON MOLD FUGUS-TYPE BULKING IN APPARATUS FOR PURIFYING WASTE WATER WITH ACTIVE SLUDGE

摘要

PURPOSE:To speedily recover the precipitating property of active sludge which has formed mold fungus-type or unfiliform non mold fungus-type bulking, by maintaining an aerating gas-feed condition at a level higher than 6Nm3/m2 expressed in terms of oxygen to be fed into a vessel. CONSTITUTION:When an amount of air 5 to be fed into crude water 6 in an aeration vessel 1 through a sparger 4 from a blower 3 is about two times or more of a proper air amount, active sludge 7 which has formed mold fungus-type or non mold fungus-type bulking can not be recovered or reformed within a short period. On the other hand, about two times or more of the air amount, practically 30Nm3/m2.day of an air amount (6Nm3/m2.day expressed in terms of oxygen), is fed, an indication SV1 representing the precipitating property of the active sludge is gradually lowered by continuing said air feed for 4-20days depending on the bulking state. Thus, the bulking sludge is reformed.