Nitrogen and phosphorus removal method for biological sewage treatment

Abstract

The invention discloses a nitrogen and phosphorus removal method for biological sewage treatment, which is designed aiming at a traditional sewage treatment that a chemical agent needs to be added, the nitrogen and phosphorus removal efficiency is low and the operation cost is high. According to the nitrogen and phosphorus removal method for the biological sewage treatment, a biological tank comprises a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone and a facultative zone; the pre-anoxic zone and the facultative zone are increased so that water can be input from a plurality of points; the water conservation staying time of each zone is adjusted and an inner reflowing manner is changed; efficient phosphorus removal strains are used for carrying out nitrogen and phosphorus removal of sewage. According to the nitrogen and phosphorus removal method for the biological sewage treatment, the chemical phosphorus removal medicine does not need to be added so that the operation cost is low and the nitrogen and phosphorus removal efficiency is high; the removing rate of nitrogen and phosphorus in an urban sewage treatment process is improved to 90% so that the sludge reduction ratio reaches 10%.

Description

technical field [0001] The invention relates to the fields of environmental engineering and sewage treatment, in particular to a sewage biological treatment method for nitrogen and phosphorus removal. Background technique [0002] The eutrophication of water body is closely related to the content of nitrogen and phosphorus and the ratio of nitrogen and phosphorus content. To control the eutrophication of water body, the amount of nitrogen and phosphorus discharged into the water body must be controlled first. In recent years, many urban sewage treatment plants in our country have carried out upgrading and transformation, and the implementation of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002) Class A A standard has played an important role in slowing down the eutrophication of water bodies. [0003] Most urban sewage treatment plants use oxidation ditch, CASS, A 2 / O and its deformation process, the above-mentioned process is limited by...

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Problems solved by technology

However, because the strain is affected by factors such as organic matter, nitrate, sludge concentration, anaerobic residence time, dissolved oxygen, and nitrite in sewage, the strain can be cultivated in the laboratory. Good results have been obtained, such as double sludge denitrification phosphorus removal, but due to complex process, high investment cost, complicated operation and other reasons, it has not been able to be applied in large-scale projects

It is difficult to cultivate denitrification and phosphorus removal bacteria on a large scale in the existing sewage treatment engineering. Only by adding chemical phosphorus removal agents can the effluent meet the discharge standard

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