A method and special equipment for enhancing the mixing effect of sludge and chemicals

Abstract

A method for intensifying the mixing effect of sludge and medicament comprises the steps of conducting quick stirring on the sludge, and then conducting slow stirring on the sludge, wherein according to the quick stirring, activated sludge and a flocculating agent are quickly injected into a quick stirring mechanism, the residence time is less than 1 s, the average speed gradient and the mixing strength are controllable, a mixing function is achieved, and low shear force stability of high-volume floc is formed; according to the slow stirring, the activated sludge subjected to the quick stirring enters into a slow stirring mechanism, and granule sludge can be formed by the tapered slow stirring mechanism. The method aims at the zoogloea formed by hydrophilic negative bio-particles contained in excess sludge produced in urban sewage treatment, the zoogloea enables the sludge to achieve a better dehydration property, coagulation of the activated sludge and the flocculating agent is finished through the quick stirring mechanism, granule sludge with better hydrophobic property can be formed through the tapered slow stirring mechanism, and sludge granulation pretreatment is realized. Through the sludge granulation pretreatment, the dehydration effect of follow-up mechanical dehydration systems is intensified, the dehydration efficiency is improved, and the consumption of the flocculating agent is reduced.

Description

technical field [0001] The invention belongs to the field of environmental engineering sludge treatment, and relates to a pretreatment technology and equipment for excess sludge generated from urban domestic sewage treatment. Background technique [0002] At present, more than 90% of the urban sewage treatment in the world adopts the activated sludge treatment method, but the result will produce a large amount of excess sludge with a moisture content of more than 99%, accounting for about 0.3% to 0.5% of the treated water volume. If advanced treatment is adopted The amount of sludge will increase by 0.5 to 1.0 times. Countries have established programs to recycle and reuse excess activated sludge. The common method is to landfill or apply it to the soil as nutrients, but these methods will cause secondary pollution to the environment. Therefore, the new law strictly prohibits the disposal of biosolids and landfill, and the sludge must be reduced, stabilized, and harmless, a...

AI Technical Summary

Problems solved by technology

Traditional mixing is only a single mechanical agitation. The sludge and chemicals are not mixed thoroughly in the mixing tank. The performance of the mixed sludge particle flocs is not stable and the compactness is poor. Even after subsequent mechanical dehydration treatment, the highest It can only reduce the moisture content to about 75%, and further deep dehydration is achieved by sludge drying and other methods, which requires additional energy consumption

Therefore, even if the sludge and chemicals are mixed mechanically, the target of a dehydration rate of 65% cannot be achieved by conventional dehydration methods.

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