Waste water treatment process and system for biological phosphorus elimination

摘要

In a process and assembly to eliminate phosphorous from water effluent, the water is treated in an activated sludge process and a stage which extracts water (especially containing carbonic acid). In a pre-treatment process, separated primary sludge is fermented to a pH 4.0-8.0 and/or a redox potential in the range (-100)-(-400) mV, with reference to a silver chloride electrode. The fermented primary sludge is rich in carbonic acid, which after washing out and separating the fermented primary sludge, is extracted in the form of carbonic acid-enriched washing water. This product can then be transferred to the anaerobic stage of an activated sludge treatment basin in which it serves as a source of nutrition and energy for micro-organisms which remove phosphates from the water.