System and method for deeply denitrifying and dephosphorizing tail water of sewage disposal plant

Abstract

The invention discloses a system and method for deeply denitrifying and dephosphorizing tail water of a sewage disposal plant. The system comprises an ultrafiltration unit, a reverse osmosis unit, a high-density sedimentation tank, an anoxic tank, an aerobic tank, a membrane bioreactor and a sludge tank. The tail water of the sewage plant is lifted to the ultrafiltration unit, a built-in membraneassembly is used for removing colloid, suspended matter and the like, ultrafiltration production water is lifted to the reverse osmosis unit, dissolved salts and organic pollutants in the water are removed through the reverse osmosis membrane assembly, and reverse osmosis production water reaches the standards for discharge. Ultrafiltration concentrated water returns to a water inlet end of the sewage plant, reverse osmosis concentrated water automatically flows into the high-density sedimentation tank, and total phosphorus is removed by mixing, coagulation and addition of agents; discharged water sequentially enters the anoxic tank and the aerobic tank, and total nitrogen is removed by nitrification and denitrification. A sludge-water mixed solution flowing out of the tail end of the aerobic tank enters the membrane bioreactor, ammonia nitrogen and COD are further decomposed under the action of high-concentration activated sludge, sludge-water separation is achieved through interception of ultrafiltration membranes in the sludge tank, and purified water is pumped by a pump and then mixed with the reverse osmosis production water for discharge.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to a system and method for advanced treatment of sewage, in particular to a system and method for deep denitrification and phosphorus removal of tail water of a sewage treatment plant. Background technique [0002] With the development of the social process and the increase of human activities, a large amount of nutrients such as nitrogen and phosphorus in industrial wastewater and domestic sewage are discharged into lakes, reservoirs and other water bodies, causing eutrophication, and aquatic organisms, especially algae, will reproduce in large numbers and destroy water bodies. The ecological balance is very unfavorable to the surrounding environment and the health of residents. [0003] In recent years, my country has revised the "Environmental Protection Law of the People's Republic of China", further clarified the government's responsibility for environmental prot...

AI Technical Summary

Problems solved by technology

The electrolysis method consumes a lot of energy, the denitrification efficiency is not high, and it is not suitable for large-scale sewage treatment plants to upgrade the project; the advanced oxidation method has a large amount of sludge and also has secondary pollution

[0007] The dual-membrane process can effectively intercept suspended solids, colloids, dissolved salts, organic pollutants, etc., and the dual-membrane process is used to treat the tail water of sewage plants containing low concentrations of nitrogen and phosphorus. "Standard" (GB3838-2002) Class III standard limit value, but the concentrated water discharged by the double membrane process accounts for about 20% to 35% of the total influent, and contains a large amount of polluting components, including a large amount of nutrients such as nitrogen and phosphorus. , if it is discharged without effective treatment, there is bound to be a risk of polluting the surrounding water environment and endangering the health of nearby residents

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