PROCESS FOR REMOVING PHOSHATES FROM WATER

摘要

For the biological removal of phosphate from water or waste water, bead-shaped biocatalysts having polymer-fixed microorganisms are used. The biocatalysts are prepared from a solution of polyvinyl alcohol and microorganisms in water by dropwise addition and shock freezing in a very cold liquid medium and subsequent slow thawing of the resulting beads, which as a result become elastically deformable and very stable. Treatment of the water or waste water by the biocatalysts is carried out in a reactor with the addition of oxygen and of suitable carbon-containing compounds. Microorganisms are used which can store phosphate at up to about 20% of their dry weight. If the biocatalysts are loaded to a large extent, regeneration is carried out by not supplying any further water or air to the reactor, the phosphate, as a result, returning to the water from the biocatalysts. This water, having a relatively high concentration of phosphate, is discharged and calcium phosphate is precipitated therefrom. The bead-shaped biocatalysts used are resistant to abrasion and are mechanically stable and can thus be used for a multiplicity of cycles.