Patent ID: 6086766
Filing Date: 2000-07-11
Classification: C02F,Y02W

Abstract:
A process for aerobically treating an aqueous organic waste in an aeration tank in the presence of a biosludge containing aerobic microorganisms, comprising the steps of:subjecting the aqueous organic waste in the aeration tank to an aerobic biological treatment in the presence of an activated biosludge containing aerobic microorganisms to generate a mixed liquor containing the activated biosludge and the aqueous organic waste;subjecting the mixed liquor to solid/liquid separation to form a treated separated liquid phase and a separated biosludge;forming a biosludge-containing liquor from a part of either mixed liquor withdrawn from the aeration tank or the separated biosludge;treating the biosludge-containing liquor in an ozone-treatment vessel with ozone by injecting an ozone-containing gas into the biosludge-containing liquor at a rate of 0.002-0.05 gram ozone per gram VSS to form a foam layer and a liquor containing the ozonized biosludge; andsupplying a liquor containing the ozonized biosludge to the aeration tank,wherein a mixed flow of the ozone-containing gas and one of biosludge-containing liquor to be treated and ozonized biosludge-containing liquor is passed in a downward flow through a pipe at a gas/liquor flow rate ratio in the range of 0.1 to 1 and a gas linear velocity of 0.4-4 m/sec and introduced into the ozone-treatment vessel in such a state that the ozone-containing gas is dispersed as finely disintegrated bubbles within the biosludge-containing liquor so that the biosludge-containing liquor contacts with the ozone-containing gas.