Process for the improved separation of clarified liquid from biomass in the biological treatment of sewage

Abstract

The present invention relates to a process for the improved separation of clarified liquids from biomass in the aerobic and/or anaerobic biological treatment of sewage carried out using magnetically separable materials as carriers. The magnetically separable inorganic materials are used in quantities of from 1 to 150% by weight, based on activated sludge dry matter. The carriers consist of magnetically separable inorganic materials. The magnetically separable materials used are oxides or mixed oxides of heavy metals, preferably iron oxides, such as Fe.sub.3 O.sub.4 (magnetite) and .gamma.-Fe.sub.2 O.sub.3, which are used in average particle sizes of less than 50 .mu.m, preferably less than 10 .mu.m and more preferably less than 3 .mu.m (for example from 0.1 to 1 .mu.m). These magnetic carriers provide for improved sedimentation or for magnetic separation of the biomasses containing the magnetic materials in the biological treatment of sewage.

Dependencies are inferred from the claim text.