摘要 |
<p><P>PROBLEM TO BE SOLVED: To attain further an improvement in treatment efficiency and the reduction of excessive sludge production amount while keeping the stable quality of treated water in a multistage activated sludge method utilizing the predation of microorganisms. <P>SOLUTION: This biological treatment method for organic waste water comprises a first biological treatment process of transforming BOD (biological oxygen demand) in organic waste water to dispersed fungus bodies through high load treatment and a second biological treatment process of flocculating the transformed dispersed fungus bodies and allowing the microorganisms to coexist. The second biological treatment process is performed under conditions of pH 5-6. Otherwise, such an excessive sludge treatment process that sludge of the second biological treatment process and/or at least a part of the sludge obtained by solid-liquid separation of the sludge of the second biological treatment process is decomposed under aerobic conditions and the treated sludge is returned to the first biological treatment process and/or the second biological treatment process is performed under conditions of pH 5-6. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |