Multistage anaerobic/anoxic/oxic activated sludge process

Abstract

The invention relates to a multistage anaerobic / anoxic / oxic (AAO) activated sludge process, which contains the following concrete technological steps of: M stages of AAO are combined and are connected with a sedimentation basin; sewage is distributed and enters into the head end of an anaerobic tank of each stage in the system respectively according to the flow; original sewage and one part of returned sludge in the sedimentation basin are mixed and then enter into the first-stage anaerobic tank; an effluent mixed liquor is mixed with the other part of the returned sludge and then a mixed liquor flows through the first-stage anoxic tank and the first-stage oxic tank...; after the second stage, the original sewage and a mixed liquor from the end of the last-stage anoxic tank are mixed and then enter into the m-stage anoxic tank and the m-stage aerobic tank; in circulation, an effluent of the final-stage aerobic tank enters into the sedimentation basin; part of the returned sludge from the sedimentation basin returns to the head end of the first-stage anaerobic tank, and the other part returns to the head end of the first-stage anoxic tank. The invention has beneficial effects of ''one carbon source for two uses'' and realization of denitrification and phosphorus uptake at the same time.

Description

technical field [0001] The invention belongs to sewage treatment technology, in particular to a multi-stage anaerobic-anoxic-aerobic activated sludge process. Background technique [0002] At present, the common activated sludge process generally has the following three types: [0003] 1. Anaerobic / Anoxic / Oxic (abbreviated as AAO) process is composed of three-stage biological treatment devices. The difference between it and the single-stage AO process is that an anaerobic reactor is set in the front stage, which aims to degrade and remove some refractory organic substances in the wastewater through the anaerobic process, thereby improving the biodegradability of the wastewater and providing for subsequent deficiencies. The oxygen section provides a carbon source suitable for the denitrification process, and finally achieves the purpose of efficiently removing COD, BOD, N, and P. The process flow of the AAO system is: the wastewater enters the anaerobic reactor after pretre...

AI Technical Summary

Problems solved by technology

This process has the advantages of saving carbon sources and high efficiency of nitrogen and phosphorus removal, but because it contains two internal reflux systems, the operation and management costs are increased; Multilevel Anoxic / Oxic (abbreviated as MAO) is based on The AAO deformation process developed by the traditional pre-denitrification process (AO) usually does not need to set up internal reflux facilities, and the volume of the biological pool is smaller than that of the ordinary phosphorus and nitrogen removal process. The average sludge concentration of the system is high and the nitrogen removal efficiency is high. High, easy to operate and manage

However, this process is mainly based on nitrogen removal, and it is difficult to achieve a high level of simultaneous biological phosphorus removal efficiency.

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