Anaerobic digestion sludge dewatering method

Abstract

The invention discloses an anaerobic digestion sludge dewatering method. By a struvite crystallization method, sludge is adjusted to be weakly alkaline, then magnesium salt is added so as to form insoluble magnesium ammonium phosphate (commonly known as struvite) crystals. On such basis, an organic flocculant is added, and colloidal particles are destabilized through electrical neutralization, collide with one another and re-aggregate into large particles, so that the floc particle size can be effectively increased, and thus the sludge dewatering performance is enhanced. The biodegradable organic flocculant is used, so that the anaerobic digestion sludge dewatering method is an environment-friendly green sludge dewatering treatment scheme; moisture content of sludge can be reduced to 50% or below, the reduction effect of pressure dewatering equipment can be greatly improved, and subsequent disposal and utilization are facilitated; in addition, based on an idea of turning wastes into treasures and recycling, the nitrogen and phosphorus removal rate is high, and the precipitated product struvite in the sludge is a slow-release fertilizer which can form soil-crop-animal-human-soil phosphorus cycle.

Description

technical field [0001] The invention relates to the field of sewage sludge treatment, in particular to a method for anaerobically digesting sludge dehydration. Background technique [0002] With the continuous improvement of my country's urbanization level, the construction of sewage treatment facilities has developed rapidly. In the process of urban sewage treatment, the sewage can be discharged up to the standard after a series of treatments, and a large number of pollutants are enriched, concentrated and transferred to the sludge. Sludge is the most important by-product of sewage biological treatment, and it is also considered to be one of the main sources of secondary pollution of water environment. Sludge from urban sewage treatment plants not only has high water content, is perishable, and has a strong odor, but also contains a large number of pathogenic bacteria, parasite eggs, heavy metals such as chromium and mercury, and toxic, harmful and carcinogenic substances ...

AI Technical Summary

Problems solved by technology

With the operation of the new sludge treatment and disposal process route of the sewage treatment plant - "advanced anaerobic digestion" process, it can effectively decompose the macromolecular organic matter in the sludge, realize the stabilization of the sludge, and form anaerobic digestion sludge Often the particles are small and the alkalinity is high, and it is difficult to achieve efficient dehydration of sludge by common chemical conditioning methods

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