| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a device which does not require a process of drawing up an immersion membrane in an aerobic digestion tank for cleaning it with chemicals, which suppresses aggregation of foreign matter in sludge causing entangling with the immersion membrane in the aerobic digestion tank and which suppresses fracture or coating of the surface of the immersion membrane. <P>SOLUTION: The biological treatment device is equipped with an OD tank 1 to biologically treat sewage, a final sedimentation tank 3 to separate the liquid biologically treated in the OD tank 1, an ozone reaction tower 10 to treat excess sludge of the sludge separated in the final sedimentation tank 3 with ozone to modify it, and an aerobic digestion tank 5 separately disposed from the OD tank 1 so as to biologically treat the modified sludge in the ozone reaction tower 10. The device is further provided with a pulverizing machine 12 to pulverize foreign matters in the sludge to be treated by immersion membranes 6, 7 disposed in the aerobic digestion tank 5. <P>COPYRIGHT: (C)2003,JPO</p> |
