A system for recycling urban waste water

Abstract

The invention relates to a system for treating urban waste water in a recycling manner. The system comprises a pretreatment unit, a biological reactor and an alga harvesting unit; urban waste water enters the pretreatment unit, then enters the biological reactor and finally enters the alga harvesting unit, after that, the outlet water is discharged. The system is characterized in that the pretreatment unit comprises a grizzly screen, an adjusting neutralization tank, a hydrolytic acidification unit and an anerobic fermentation unit; the number n of gaps of the grizzly screen satisfies the following formula: n=Qmax(sin[alpha])1 / 2 / (dhv), wherein n refers to the number of the gaps of the grizzly screen, Qmax refers to the maximum design flow (m<3> / h), alpha refers to the mounting tilt angle (degree) of the grizzly screen, d refers to grid gaps (mm) of the grizzly screen, h refers to the depth (m) of water in front of the grizzly screen, and v refers to the speed of water flowing through the grizzly screen. The system has the benefits that products with high added values in harvesting of microalgae can be utilized effectively, so that the economic benefits and the social benefits of wastewater treatment can be increased greatly, and a practicable method and system are provided for recycling and comprehensive treatment of waste water.

Description

technical field [0001] The invention relates to a system for recycling urban waste water. Background technique [0002] In the prior art, urban sewage treatment is generally divided into three levels: first-level treatment, which uses physical treatment to remove insoluble pollutants and parasite eggs in sewage; second-level treatment, which uses biological treatment to remove various Complex organic matter is oxidized and degraded into simple substances; tertiary treatment uses chemical precipitation method, biochemical method, physical chemical method, etc. to remove phosphorus, nitrogen, refractory organic matter, inorganic salts, etc. in sewage. As for which level of treatment is more reasonable, it should be determined according to the treatment requirements for the final effluent. [0003] However, the above-mentioned treatment methods have become obsolete and cannot solve the urban sewage pollution problem well. Contents of the invention [0004] The technical pro...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is: the method and system method of harvesting and extracting biodiesel is to add specific domesticated microalgae to the municipal wastewater after certain pretreatment, and after fully mixing and reacting in a specific bioreactor , N, P and organic matter in the wastewater are gradually removed as energy sources for microalgae. At the same time, the oil content in the microalgae gradually accumulates. When the pollutants in the water are degraded to a certain level, the microalgae are harvested through the microalgae harvesting device. , and refined into biomass energy or other biological products, and the waste water is discharged up to the standard

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