WERKWIJZE OM RIOOLWATER TE ZUIVEREN.

摘要

1368874 Activated sludge process BIOSPHERICS Inc 19 May 1972 23802/72 Heading C1C In an activated sludge process sewage is mixed with activated sludge containing precipitated phosphate, the mixture is aerated to reduce its BOD content and to cause microorganisms to take up phosphate, and the aerated mixture is settled to produce a substantially phosphate-free effluent and activated sludge, at least a portion of which sludge is treated (a) to release phosphate from the microorganisms into the liquid phase of the sludge and (b) to precipitate the water-soluble phosphate and then recycled. In step (a) the sludge may be aerated or maintained under anaerobic conditions, or may have its pH reduced to less than 6À5. The precipitant in step (b) may be an aluminium or iron salt (e.g. alum) or lime. The effluent may be chlorinated.