Device and method for bypass phosphorus recovery of town sewage treatment plant

Abstract

The invention discloses a device and a method for bypass phosphorus recovery of a town sewage treatment plant, and belongs to the technical field of sewage treatment and resource recycling. The device comprises a general sewage treatment subsystem and a bypass phosphorus recovery subsystem, wherein the general sewage treatment subsystem comprises a sewage anaerobic biochemical treatment pond, a sewage aerobic biochemical treatment pond and a secondary settling pond; and the bypass phosphorus recovery subsystem comprises an anaerobic phosphorus releasing pond, a phosphorus stirring and crystallizing pond and a crystal recovering pond. The method comprises the following steps in sequence: initially concentrating the pretreated sewage by the general sewage treatment subsystem, so as to obtain sludge; feeding the sludge into the anaerobic phosphorus releasing pond by a sludge scrapping and absorbing machine to release the phosphorus for 60 minutes; transferring the supernate into the phosphorus stirring and crystallizing pond, and feeding magnesium chloride solution and saturated ammonia water into the phosphorus stirring and crystallizing pond to react with the supernate, so as to obtain a magnesium ammonium phosphate crystal; and recovering the magnesium ammonium phosphate crystal by the crystal recovery pond. By adopting the device and method, the problems of the sewage treatment plant that the biological phosphorus removal method is low in efficiency and the chemical phosphorus removal method is high in cost, can be effectively solved, and the recovered phosphorus is of high value in use, so that the recycling of the phosphorus resource is realized, and higher economic value and social value are provided.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment and resource recycling, and in particular relates to a device and method for recycling phosphorus in a side channel of an urban sewage treatment plant. Background technique [0002] The pollution of phosphorus to water body is mainly manifested in excess nutrition, which causes eutrophication of water body. When the phosphorus content in the water body is lower than 0.5mg / L, the excessive growth of algae can be controlled; and when the phosphorus content in the water body is lower than 0.05mg / L, the algae almost stop growing. Urban sewage treatment plants are an important way to control the entry of phosphorus into the water environment. Therefore, by adopting appropriate treatment processes and effective recovery methods, sewage plants can not only effectively control the eutrophication of water bodies, but also obtain available phosphorus resources. Both pollution and prolonged use of ...

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Problems solved by technology

[0003] The phosphorus content of incoming water from urban sewage treatment plants is usually 5-15 mg / L, and the annual average phosphorus content of sewage is 7-8 mg / L. Now the biological treatment process commonly used in sewage treatment plants is A 2 / O or A / O process, the removal efficiency of phosphorus is generally not more than 50-60%, so the effluent cannot meet the requirements of the national first-class A or first-class B

Due to the difference in water retention time requirements of phosphorus accumulating bacteria and denitrification bacteria in sewage biological treatment, denitrification is usually the main purpose, so phosphorus removal usually needs to be supplemented by chemical phosphorus removal, but the chemical sludge produced by chemical phosphorus removal It cannot be recycled, resulting in waste of phosphorus resources; and improper disposal of chemical sludge will still cause environmental pollution

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