Biological sewage treatment device and method for synchronous nitrogen and phosphorus removal and sludge reduction

Abstract

The invention discloses a biological sewage treatment device and a biological sewage treatment method for synchronous nitrogen and phosphorus removal and sludge reduction. The device comprises a water inlet pipe 1, an anaerobic pond 2, a mid-sedimentation tank 3, an intermediate pool 4, a BAF 5, an anoxic pond 6, a post-aeration tank 7, a secondary sedimentation tank 8, and a water outlet pipe 9 in series connection in order; the treatment process comprises the following steps: mixing raw water and P-rich returned sludge in the anaerobic pond, wherein denitrifying phosphorus accumulating bacteria (DPBs) absorb and store VFA in a body in a form of PHB (poly-beta-hydroxybutyrate) and release a large amount of phosphorus; removing VOD remained in the BAF and nitrating the nitrogen; introducing BAF nitrification liquid and the sludge in the mid-sedimentation tank into the anoxic pond together, wherein the DPBs performs denitrification for absorbing the phosphorous by using the PHB in the body as an energy source and a carbon source and using NO3<-> as an electron acceptor; removing the unnecessary phosphorus contained in the post-aeration tank and blowing off the nitrogen to prevent the sludge from floating upwards; discharging the supernatant in the secondary sedimentation tank, wherein part of the sludge containing a large amount of DPBs is refluxed and the remaining sludge is discharged. The biological sewage treatment device and the biological sewage treatment method for the synchronous nitrogen and the phosphorus removal and the sludge reduction resolves the conflict between the denitrification and the phosphorous removal, and ensures the stable water quality of effluent and low yield of the sludge.

Description

technical field [0001] The invention belongs to the field of sewage treatment, in particular to a sewage biological treatment device and method for synchronous nitrogen and phosphorus removal and sludge reduction. Background technique [0002] A large amount of excess sludge produced in aquatic biological treatment has caused great pressure on the environment, and its treatment and disposal costs are high, which has become a bottleneck restricting the development of the sewage industry. In this context, sludge reduction technology has become a hot research topic in the sewage industry. The so-called sludge reduction refers to the use of physical, chemical and biochemical means to minimize the amount of biological solids discharged from the entire sewage treatment system. However, the current sludge reduction technologies have disadvantages. The physical method has economic problems, the chemical method has environmental safety problems, and the biochemical method has the pr...

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Problems solved by technology

[0005] The purpose of the present invention is that the purpose of the present invention is to propose a sewage biological treatment method for synchronous denitrification and phosphorus removal and sludge reduction for the respective defects of the current sludge reduction and BAF, combining activated sludge and BAF to form The dual-sludge system can not only solve the problem of poor BAF biological phosphorus removal effect, but also realize nitrogen and phosphorus removal while reducing the amount of sewage treatment sludge

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