摘要 |
<p>A method of biologically cleaning polluted water uses active sludge and at least three zones, where at least one zone operates as a biological treatment zone and at least two zones variably operate as a biological treatment zone and as a clarifying zone. By this method, the polluted water is fed to a zone operating as a permanent biological treatment zone, where a back-mixing is performed during a period between this zone and a zone variably operating as a biological treatment zone and which has operated as a clarifying zone during a previous period. As a result, the drawbacks are overcome which the known T- and V-channel methods are encumbered with.</p> |