| 摘要 |
PURPOSE:To obtain a septic tank wherein installation cost and the space for installation are small and maintenance is easy and throughput is large and only treated clear water is discharged while one part of water to be treated in a catalytic aeration tank is returned to an anaerobic filter bed. CONSTITUTION:In a septic tank provided with a return path B through which sludge in a catalytic aeration tank E provided to the downstream of an anaerobic filter bed tank N is returned to this anaerobic filter bed tank N, an ascending flow path A due to air lift is provided to the catalytic aeration tank E and connected to the return path B. Moreover a membrane filter M is arranged in the position higher than the water surface of the septic tank by the ascending flow path A. A discharge part W of treated water discharged from the membrane filter M is arranged in the position lower than this membrane filter M. |
