Rain sewage retention tank with function of coagulation sedimentation

Abstract

A rain sewage retention tank with a function of coagulation sedimentation comprises a mixing tank, a first flocculation tank, a second flocculation tank, a third flocculation tank, a sedimentation tank and a water collection tank, wherein a stirring device is respectively arranged in the mixing tank, the first flocculation tank, the second flocculation tank and the third flocculation tank. A water inlet of the mixing tank is connected with a water inlet pipe, the mixing tank is communicated with the first flocculation tank through a first water passing hole, the first flocculation tank is communicated with the second flocculation tank through a second water passing hole, the second flocculation tank is communicated with the third flocculation tank through a third water passing hole, the second flocculation tank and the third flocculation tank are respectively provided with a plurality of water passing holes communicated with the sedimentation tank, the sedimentation tank is communicated with the water collection tank through an overflow dam opening at the top of the sedimentation tank, and a water outlet pipe is arranged on the water collection tank. The rain sewage retention tank is low in building cost and high in removal rate of turbidity and chemical oxygen demand (COD) of original rainwater. The removal rate of the turbidity and the removal rate of the COD can both reach more than 90%, so that pollution of the original rainwater on water bodies is greatly reduced.

Description

technical field [0001] The invention relates to a rainwater storage pond. In particular, it relates to a rainwater storage tank with coagulation and sedimentation function, which combines the enhanced coagulation and sedimentation technology with the rainwater storage tank, so that the rainwater can be adjusted and stored, and the removal efficiency of pollutants in the initial rainwater can be increased. Background technique [0002] Initial rainwater pollution is the main part of urban pollution. In highly urbanized areas with high surface pollution loads, even if a separate drainage system is adopted, the direct discharge of initial rainwater will cause serious damage to the receiving water body. In some cities that have implemented separate drainage systems, after a period of operation, the pollution of the surrounding water bodies has not improved significantly. The initial runoff formed by rainfall contains a large amount of pollutants, such as BOD, SS, TN, TP, heavy ...

AI Technical Summary

Problems solved by technology

However, the current domestic and foreign storage tank design and specification requirements are relatively large in size and occupy a relatively large area

so that its application in the city is limited

[0005] General rainwater storage tanks only rely on the natural precipitation of gravity to remove pollutants, but if a satisfactory treatment effect is achieved, the hydraulic retention time is very long, resulting in a large design volume of the storage tank, which increases the floor area and construction cost

[0006] In "Discussion on the Disposal of Initial Rainwater Runoff" (China Water Supply and Drainage. 2009.19(25): 106-108), the water quality monitoring of initial rainwater runoff found that its biodegradability is poor, and the main pollutants are SS and COD. And the contribution rate of SS to COD is larger

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