ANAEROBIC BIOLOGICAL PROCESSING DEVICE AND METHOD FOR ORGANIC WASTE LIQUID

PROBLEM TO BE SOLVED: To provide an anaerobic biological processing device and method, wherein: membrane filtering can be carried out without releasing anaerobic gas to the air in a constant operation state by preventing the fluctuation of an in-tank pressure in the anaerobic biological processing device; the securement of a high in-tube speed by small dynamic pressure by a gas lift effect and the securement of an intermembrane differential pressure by forced filtration using a suction pump can be compatibly established; and high flux can be stably maintained.SOLUTION: The anaerobic biological processing for the organic waste liquid is carried out by the anaerobic processing device 1, the anaerobic processing liquid and the anaerobic gas of the anaerobic processing device 1 is introduced into the lower part of the tubular filter membrane element 7 of a membrane filtering device 2 and lifted by the gas lift, the filtrate is sucked and taken out from a filtrate taking-out passage L4 by a suction pump P2, thereby the membrane filtering is carried out. A gas phase part 5b formed in the upper part of a filtrate storing tank 5 is communicated with the gas phase part 1b of the anaerobic processing device 1, thereby equalizing the pressures of both the part. Thus, pressure fluctuation does not occur in the anaerobic processing device 1, and the aerobic biological processing is constantly carried out, even though the filtrate is sucked by the suction pump P2 in a membrane filtering step.