A device and method for deep denitrification of secondary effluent of urban sewage plant

Abstract

The invention discloses a device and method for deep denitrification of the secondary effluent of an urban sewage plant, which transforms part of the aerobic zone of a traditional A / O activated sludge reactor into a denitrifying anammox biofilm reactor; when used A part of urban sewage enters the A / O activated sludge reactor for traditional nitrification and denitrification denitrification, and the effluent of the A / O activated sludge reactor enters the secondary settling tank for mud-water separation; the effluent of the secondary settling tank is mixed with another part of urban sewage , enter the denitrification anammox biofilm reactor, use the limited organic matter in the urban sewage to reduce the nitrate nitrogen contained in the effluent of the secondary sedimentation tank to nitrite nitrogen, and then anaerobically react with the ammonia nitrogen contained in the urban sewage Oxyammonium oxidation reaction further reduces the concentration of nitrate nitrogen in the effluent of the secondary sedimentation tank to achieve the purpose of deep denitrification. The invention can enable the urban sewage plant to realize deep denitrification under the condition of increasing the amount of treated water and without external carbon source, and can achieve double benefits of standard raising and energy saving.

Description

technical field [0001] The invention relates to the technical field of sewage biological treatment, in particular to a device and method for deep denitrification of secondary effluent of urban sewage plants. Background technique [0002] On the one hand, with the continuous acceleration of urbanization and the continuous increase of urban population, the daily treatment water volume of urban sewage treatment plants exceeds the design water volume, resulting in overload operation. At the same time, the country's requirements for water environment quality continue to increase, and the discharge standards of sewage plants continue to increase, making most urban sewage treatment plants face upgrading and transformation. Most of the existing urban sewage treatment plants adopt the traditional anoxic and aerobic (A / O) biological denitrification process, such as figure 1 The shown traditional anoxic aerobic biological denitrification device comprises urban sewage raw water tank 10...

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Problems solved by technology

[0003] However, in the above-mentioned traditional anoxic and aerobic biological denitrification process, the reflux of nitrification liquid is limited, which leads to the limitation of total nitrogen removal rate of the system, and it is difficult to meet the national discharge standard for effluent total nitrogen.

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