| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a sewage treatment method which enables a biological treatment such as nitrification and denitrification with a very high efficiency by enhancing the concentration of MLVSS in MLSS. <P>SOLUTION: In the sewage treatment method, prior to biological treatment of a sewage W1 within treatment tanks 10, 11, a major part of organic and inorganic suspended solids contained in the sewage W1 is coagulated followed by solid liquid separation with a separator/dehydrator 8. Highly concentrated activated sludge organic suspended solids (MLVSS) obtained by introducing the treated sewage from the treatment tank 11 into a membrane separation tank 12 for concentration are returned to the treatment tank 10 and are recirculated. The coagulation and solid liquid separation of the sewage W1 can enhance the MLVSS/MLSS ratio and can enhance the concentration of MLSS circulated through the membrane separation tank 12 to maintain MLVSS at a high concentration and thus to significantly improve the denitrification efficiency. <P>COPYRIGHT: (C)2009,JPO&INPIT |
