| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently and economically conduct separation-membrane treatment in an anaerobic state. SOLUTION: Sewage 8 is brought into contact with activated sludge or biological membrane in a biological treating tank 2 under anaerobic or intermittently anaerobic and aerobic conditions, and treated water 9 is separated by a separation membrane 3 dipped in the tank. Ananaerobic or oxygen-poor gas is introduced into a liq. phase in the tank 2 to keep the inside of the tank anaerobic, and the dipper membrane is cleaned. The gas in the treating tank is circulated and used as the anaerobic or oxygen-poor gas, or a gas 10 from an anaerobic gas tank 1 which is communicated with the treating tank and provided separately, is used.</p> |
