Coupled sewage biological nitrogen and phosphorus removal and phosphate recovery method

Abstract

The invention relates to a coupled sewage biological nitrogen and phosphorus removal and phosphate recovery method. According to the method based on a biological nitrogen and phosphorus removal mainstream process of a sewage plant, phosphorus releasing ponds which operate in a side stream sequencing batch manner and are coupled with the main stream process is arranged, the amount of sludge introduced into a secondary sedimentation tank of each of the phosphorus releasing ponds is based on the volume ratio of water inflow: sludge inflow of the phosphorus releasing pond=(0.5-2.0): 1, and the total sludge amount entering into the phosphorus releasing pond everyday is below 10% of the daily average flow rate of the sewage plant; each of the phosphorus releasing ponds operates 2-4 periods everyday, and residual sludge is discharged from the phosphorus releasing ponds. The phosphorus releasing ponds can be flexibly adjusted according to a result of pilot run of the phosphorus releasing ponds and phosphate recovery, the phosphate is recovered to the optimum extent, and the biological treatment effect of the sewage is improved. According to the method provided by the invention, not only do the sewage treatment indexes meet the national discharge standard, but also phosphorus in the sewage can be recovered. The method is a sewage treatment and resource recovery method in sustainable development and is suitable for a newly constructed municipal sewage treatment plant or a constructed sewage plant with a nitrogen and phosphorus removal function.

Description

technical field [0001] The invention relates to a method for coupled sewage biological denitrification and phosphorus removal and phosphate recovery, in particular to a sewage biological denitrification and phosphorus removal method and a method for phosphate recovery in the sewage biological treatment process. The invention belongs to the technical field of sewage biological treatment. Background technique [0002] Phosphorus is a natural resource that is almost non-renewable and replaceable. It is reported that according to the existing mining technology, the phosphate rock that can be mined on land in the world can only be used for about 50 years. On the other hand, excessive discharge of phosphorus from human society is one of the important causes of water eutrophication. [0003] In the process adopted by traditional domestic sewage treatment plants, phosphorus removal uses a type of microorganism called phosphorus accumulating bacteria (PAO). PAO absorbs organic matte...

AI Technical Summary

Problems solved by technology

The role of the anaerobic tank is to allow the PAO to get enough carbon source to release phosphorus, so as to ensure the absorption of phosphorus in the subsequent aerobic tank, not specifically for the recovery of phosphate, in some cases, such as when the sludge load is low , the phosphate concentration in the anaerobic tank will be relatively low, making the next chemical precipitation step more difficult. If the phosphate concentration in the anaerobic tank is increased by adding carbon sources or changing the volume and working parameters of the anaerobic tank , is questionable economically, and may affect the stability of the entire biological treatment system

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