| 摘要 |
PCT No. PCT/DK95/00309 Sec. 371 Date Mar. 12, 1997 Sec. 102(e) Date Mar. 12, 1997 PCT Filed Jul. 14, 1995 PCT Pub. No. WO96/02468 PCT Pub. Date Feb. 1, 1996A method and plant for the purification of polluted water by the activated sludge method is provided in that a mixture of polluted water and recycled sludge is subjected to biological treatments in at least two treatment zones, and maintaining for a period such conditions in one of the treatment zones that a sludge precipitation occurs therein, supplying in a subsequent period the mixture of polluted water and recycled sludge directly or indirectly to the zone which, during the preceding period, served as a sludge precipitation zone prior to further treatment thereof in one or more treatment zones, and passing the treated water to a permanent clarification zone and separating it into a water fraction and a sludge fraction, at least a part of the sludge fraction being recycled and mixed with polluted water.
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