Method for recycling heavy sludge and enhancing nitrogen and phosphorus removal

Abstract

The invention provides a method for recycling heavy sludge and enhancing nitrogen and phosphorus removal, wherein the method comprises the following steps: (1) successively introducing sewage passingthrough a pretreatment unit into an anaerobic pool, an anoxic pool and an aerobic pool; (2) making the mixed liquid treated by the aerobic pool partially flow back to the anoxic pool, and introducingthe remaining part into a secondary sedimentation pool; and (3) introducing all or a part of sludge produced by the secondary sedimentation pool into a hydrocyclone or a centrifuge, carrying out cyclone or centrifugal treatment, allowing heavier sludge to flow back to the anaerobic pool by a heavy sludge reflux pipeline, allowing lighter sludge to enter a sludge treatment system through sludge discharge, and discharging a supernatant generated by the secondary sedimentation pool through a water outlet pipeline. The method overcomes the problem that the sludge concentration of a traditional active sludge treatment method is limited by sludge sedimentation performance of the secondary sedimentation pool and cannot be improved further, has good adaptability to water quality, and has strong anti-shock loading capability; and the wastewater treatment method does not have the problem of sludge expansion.

Description

technical field [0001] The invention relates to the field of sewage treatment, in particular to a method for strengthening the effect of traditional nitrogen and phosphorus removal by recycling heavy sludge. Background technique [0002] The water resource crisis has become one of the greatest challenges faced by human beings in the 21st century. The existing sewage treatment plants in my country are mainly aimed at organic carbon pollutants, and the removal effect of nitrogen and phosphorus elements is poor, and nitrogen and phosphorus are the main causes of water pollution. The main nutrients of eutrophication. With the continuous aggravation of eutrophication in water bodies and the improvement of water quality requirements for sewage treatment plants, the denitrification and phosphorus removal of urban sewage has attracted much attention. [0003] At present, the widely used biological nitrogen and phosphorus removal process is A 2 / O sewage treatment process, this proce...

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Problems solved by technology

[0002] The water resource crisis has become one of the greatest challenges faced by human beings in the 21st century. The existing sewage treatment plants in my country are mainly aimed at organic carbon pollutants, and the removal effect of nitrogen and phosphorus elements is poor, and nitrogen and phosphorus are the main causes of water pollution. The main nutrients of eutrophication. With the increasing eutrophication of water bodies and the improvement of water quality requirements for sewage treatment plants, the denitrification and phosphorus removal of urban sewage has attracted much attention.

[0003] At present, the widely used biological nitrogen and phosphorus removal process is A 2 / O sewage treatment process, this process solves the problem of denitrification and dephosphorization of sewage to a certain extent, but there are the following problems: 1. The concentration of activated sludge is low, which affects the stability of ammonia nitrogen in the effluent; 2. The treatment load is affected by the sludge Settling performance limitations cannot be further improved

The traditional process often increases the sludge concentration by adding fillers in the aeration tank or increasing the sludge return flow, that is, the external return flow, to increase the treatment load, but adding fillers makes the operation more complicated, increases the operating cost, and increases the sludge return flow It is also limited by the sludge settling performance of the secondary settling tank

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