A method for strengthening denitrification and dephosphorization by hydrolyzing and fermenting mixed sludge from sewage plant

Abstract

The invention creatively provides a method for strengthening nitrogen and phosphorus removal by using the hydrolysis and fermentation of mixed sludge of a sewage plant. According to the method, part of activated sludge returns to a primary sedimentation tank and is mixed with primary sedimentation sludge, so as to be subjected to precipitation and concentration, the precipitated and concentrated mixed sludge enters a hydrolysis tank which can consist of a separate reactor and can also consist of two series reactors, and is subjected to hydrolysis and fermentation in the hydrolysis tank, so as to produce easily-degradable organic matters (rbCOD) or volatile fatty acids (VFAs), and after the process is completed, a hydrolyzed mixed solution which is rich in VFA, or supernatant is introduced into an anaerobic tank or anoxic tank of a biological pool, thereby realizing the aim of strengthening nitrogen and phosphorus removal. The method provided by the invention has the advantages that the carbon source insufficiency of inlet water can be effectively improved, the biological nitrogen and phosphorus removal function can be strengthened, and the addition of an external commercial carbon source is reduced or canceled; the method is applicable to the new construction of sewage plants and is also applicable to the upgrading and reconstruction of the existing sewage plants.

Description

technical field [0001] The present invention relates to a sewage treatment method, in particular to a method of mixing and hydrolyzing primary sludge and activated sludge produced in the sewage treatment process to produce easily degradable organic matter (rbCOD) and volatile fatty acids (VFAs). Insufficient VFAs in the influent can improve the nitrogen and phosphorus removal effect of the sewage plant, reduce the demand for external carbon sources, reduce the energy consumption of aeration, and reduce the "carbon footprint". Background technique [0002] At present, my country's water environment problems are becoming more and more prominent, and the pressure of energy conservation and emission reduction is also increasing. In addition to large-scale construction of sewage treatment systems, sewage treatment plants that have been built or are in operation are also facing increasingly stringent water quality requirements, especially for N , Strict requirements for P emissions...

AI Technical Summary

Problems solved by technology

For a specific sewage plant, the amount of primary sludge generated daily is greatly affected by the influent water quality and the amount is insufficient. Although the primary sludge contains a higher concentration of easily fermentable organic matter, the primary sludge lacks a sufficient amount. Biologically active mixed flora with hydrolysis and fermentation functions, so the hydrolysis rate of pure primary sludge is low; on the contrary, the amount of activated sludge kept in sewage plants is much higher than that of primary sludge, the key Activated sludge is rich in aerobic, anoxic and facultative bacteria, which can directly provide microbial inoculation of mixed flora for the sludge hydrolysis process. The disadvantage is that the concentration of granular easily degradable organic matter contained in activated sludge is lower than that of Primary sludge, so the concentration of rbCOD in pure activated sludge hydrolyzate is often lower than that of primary sludge hydrolysis

But up to now, the process technology of mixed fermentation of two kinds of sludge has not been developed and applied in an engineering way.

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