| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To remarkably reduce the amount of generated surplus sludge; to improve and stabilize a sludge volume reduction capacity by making alkali treatment more efficient. <P>SOLUTION: A sewage treatment apparatus comprises an aeration tank 2 for biologically treating sewage 1, a sedimentation tank 3 for performing the solid-liquid separation of the biologically treated sewage to obtain treated water 4 and return sludge 5, a means for pulling out a part of the return sludge to obtain sludge, a plurality of alkali treatment tanks 8, 9 for subjecting the pulled-out sludge to two or more stages of alkali treatment, a biological solubilization tank 10 for biologically solubilizing the alkali-treated sludge under an anaerobic, anoxic or microaerophilic condition, and a sludge return means for returning the solubilized sludge to the aeration tank 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
