A method and device for deep removal of phosphorus and nitrogen from sewage

Abstract

The invention discloses a method and device for advanced sewage nitrogen and phosphorus removal. The method comprises the steps of (I) guiding raw sewage into an anaerobic tank; (II) guiding the mixed liquid after treatment in the anaerobic tank into a first solid-liquid separation unit, guiding the supernate into a nitrifying tank, and guiding the produced mud-water mixture into an anoxic tank; (III) guiding the mixture after treatment in the anoxic tank into a second solid-liquid separation unit and an aerobic tank respectively; (IV) guiding the supernate produced after treatment by the second solid-liquid separation unit into the nitrifying tank, and returning the mud-water mixture into the anoxic tank; (V) guiding the nitrified liquid after treatment in the nitrifying tank into the anoxic tank; (VI) enabling the mixed liquid after treatment in the aerobic tank to flow back to the anoxic tank, and guiding into a sedimentation tank; (VII) performing backflow and discharge on the sludge produced by the sedimentation tank. By adopting the method and device disclosed by the invention, the competition conflict for a carbon source between phosphorus removal and nitrogen removal of the sewage treatment system is solved, advanced sewage phosphorus and nitrogen removal can be realized, and the standing time of the solid-liquid separation unit is short. The method and the device are suitable for building a new sewage plant, and the transformation of an existing sewage plant is easily realized by separating tanks of the A2 / O technology.

Description

Technical field [0001] The invention relates to the treatment field of water, waste water, sewage or sludge, in particular to a method and device for deep dephosphorization and denitrification of sewage. Background technique [0002] The "Urban Sewage Treatment Plant Pollutant Discharge Standard GB18918-2002" came into effect on January 1, 2006, and put forward higher requirements for N and P in the effluent quality of my country’s urban sewage treatment plants, that is, TN≤15mg / L, NH 4 + -N≤5mg / L, TP≤0.5mg / L. NH 4 + -The simultaneous discharge of N, TN, and TP has become an important task faced by various sewage treatment plants. [0003] A 2 The / O process is a typical process for nitrogen and phosphorus removal in sewage, and most water plants in my country use this process. A 2 The / O process is a single sludge system, which is mainly composed of three stages: anaerobic, anoxic and aerobic. In the anaerobic section, the phosphorus accumulating bacteria release the phosphorus ...

AI Technical Summary

Problems solved by technology

[0006] The technical problem solved by the present invention is: to provide a method for deep dephosphorization and denitrification of sewage, which overcomes the problems of carbon source competition and sludge age contradiction, has a significant denitrification effect, reduces the content of total nitrogen and total phosphorus in the effluent, and effectively solves the problem of sewage denitrification. Dealing with Difficult Standards

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