Combined bio-filtration and chemical polishing process, to treat communal waste water plant outfall, employs biomass to generate carbonic acid

摘要

The waste water treatment plant outfall (1) is trickled over a distribution layer (7), introducing oxygen and carbon dioxide from the air, over a large area. Large volumes are distributed intermittently, the gases being taken up in the intervals. Biomass in the distribution- and base- (6) layers reacts with residual contaminants, releasing carbon dioxide. The released carbon dioxide is converted to carbonic acid in solution, and migrates through the separation layer (5) into the absorption layer (3). In the distribution layer and the base layer, nitrogen in the form of ammonia, a residual in the outfall, is converted into the nitrate form, using the entrained atmospheric oxygen. In the absorption layer, phosphate is chemically converted and bonded with lime under partial valent forces. CO2 ions from the carbonic acid, with some of the water-insoluble calcium carbonate or magnesium carbonate, for calcium hydrogen carbonate (bicarbonate) or magnesium hydrogen carbonate. This bonds with phosphates from the outfall into insoluble calcium phosphate or magnesium phosphate. The water, now freed of contaminants, phosphates and ammoniacal nitrogen, is led off by drainage into the final outfall. The process is further detailed, in accordance with the foregoing principles.