| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a membrane separation unit which requires only a small installation area when increasing the treatment capacity of an activated sludge treatment system, and can easily increase the capacity for solid-liquid separation of treated sludge in the system without stopping the system. <P>SOLUTION: The membrane separation unit U in place of an existing settling tank (a) is connected to a biological reaction tank 1, thereby the capacity for the solid-liquid separation of the treated sludge in the system can be increased without a repair work of the settling tank (a). The membrane separation unit U is equipped with a membrane module 2 that obtains treated water by filtering the treated sludge after biological reaction treatment in the biological reaction tank 1. While passing the treated sludge through the membrane module 2 at a relatively high speed, a part of the treated sludge is filtered to extract the treated water. Back washing operations are carried out for periodically passing washing water through membrane elements reversely to the filtration direction of the treated water. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
