Sewage treatment method for nitrogen and phosphorus removal through combination of biofilm process and multilevel activated sludge process

Abstract

The invention relates to a sewage treatment method for nitrogen and phosphorus removal through the combination of a biofilm process and a multilevel activated sludge process. Sewage which is delivered into an anoxic tank is distributed to respectively flow into a first anoxic tank and a second anoxic tank; the sewage which flows by the first anoxic tank then flows into an aerobic tank, and is converged with the sewage which flows into the second anoxic tank, and the converged sewage flows into a moving bed biofilm reactor (MBBR) tank to be treated and flows into a sedimentation tank; and the sewage is stopped in the sedimentation tank, part sludge is discharge into a preconcentration tank, and remains in the preconcentration tank for 0.25-1.0 hour, supernatant flows back to the second anoxic tank by passing by the top of the preconcentration tank, and the concentrated sludge is delivered to a pre-anoxic tank through a reflow passage at the bottom of the preconcentration tank, and flows back to the anoxic tank finally through the pre-anoxic tank for circulation treatment. According to the method, the biological treatment nitrogen and phosphorus removal effect is ensured through MBBR aerobic tank and preposed anaerobic zone carbon source distribution, returned sludge preconcentration and other typical technological methods, thus, the municipal sewage treatment effect is improved, and the pollution to the environment is reduced.

Description

Technical field [0001] The invention relates to the technical field of environmental protection, in particular to a method for treating nitrogen and phosphorus sewage combined with a biofilm method and a multi-stage activated sludge method. Background technique [0002] In recent years, with the rapid economic development, my country’s annual sewage discharge is about 40-50 billion m 3 Among them, only 15%-25% is discharged after treatment, and a considerable part of the sewage after the traditional secondary treatment still retains high concentrations of nitrogen and phosphorus and other nutrient pollutants, causing many rivers in my country All have produced different degrees of eutrophication pollution. Therefore, strengthening the treatment of sewage, including water quantity and quality, is of great significance for reducing pollution, improving the environment, and protecting water resources. [0003] Excessive discharge of nitrogen and phosphorus is the main reason for the e...

AI Technical Summary

Problems solved by technology

But A 2 The O process also has obvious deficiencies, for example, the denitrification and phosphorus removal effects are mutually restricted, it is difficult to achieve the ideal denitrification and phosphorus removal effect at the same time, and the control of sludge age, the distribution of carbon sources, etc. are all problems in the operation process. key points and difficulties

[0006] In order to solve the problem of poor biological nitrogen and phosphorus removal, researchers developed the moving bed biofilm reactor process, that is, the MBBR process technology

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