Method for supplementing denitrifying carbon source by utilizing excess sludge ethanol-type fermentation

Abstract

The invention discloses a method for supplementing a denitrifying carbon source by utilizing excess sludge ethanol-type fermentation, which aims at the problems of low average level of the biochemical oxygen demand 5 (BOD5) of municipal sewage in China and ubiquitous shortage of the denitrifying carbon source. The method comprises the following steps of: allowing the excess sludge which is subjected to pyrohydrolysis pretreatment to enter a fermentation reactor; cultivating and domesticating ethanol-type zymophyte by using the sludge as a matrix; controlling the fermentation reaction to be atan ethanol-type fermentation stage; refluxing the products to a pyrohydrolysis stage; controlling the pyrohydrolysis temperature to be between 120 and 130 DEG C so that substances with boiling pointslower than 120 DEG C, such as ethanol, acetic acid and the like, exist in the form of gas; and collecting a high-quality organic carbon source which mainly comprises ethanol and acetic acid in a condensation reclaiming mode. The method has the advantages that: the denitrifying carbon source which mainly comprises the ethanol and the acetic acid effectively improves the denitrification efficiency,and the problem of phosphorus accumulation of a system caused by that the sludge after anaerobic digestion is directly used as an additional carbon source is avoided due to a special carbon source extraction mode; and the method also has the advantages of simple control condition of the whole process, easy operation and low operational cost.

Description

technical field [0001] The invention relates to a method for supplementing denitrification carbon sources by using excess sludge ethanol fermentation to solve the problem of insufficient denitrification carbon sources in sewage treatment plants, and belongs to the technical field of sewage treatment. Background technique [0002] With the intensification of eutrophication in several major water systems in China, algae blooms and red tides have occurred one after another, and the national discharge standards for water bodies have also been continuously improved. Biological denitrification is the most commonly used process in urban sewage treatment. The removal of total nitrogen is ultimately through the denitrification process. The denitrifying bacteria convert the nitrate nitrogen produced by the aerobic process into N under anoxic conditions. 2 It is discharged into the atmosphere to achieve the purpose of removing total nitrogen in water. In order to achieve a better biol...

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Problems solved by technology

However, at present, my country's urban sewage BOD 5 The average level is low, and the problem of insufficient denitrification carbon source is common, which greatly limits the stable and effective function of sewage plants with biological denitrification function

[0003] Aiming at the problem of insufficient carbon sources for denitrification, early research mainly focused on adding low-molecular-weight organic substances such as methanol and ethanol to the denitrification section. This additional carbon source can increase the denitrification rate, but it is expensive

In recent years, research on external carbon sources has mainly focused on the use of industrial wastewater or landfill leachate as a carbon source for denitrification, which can not only achieve an economical way of adding additional carbon sources, but also solve the treatment problems of some industrial wastewater and landfill leachate. These wastewaters generally contain high concentrations of ammonia nitrogen, heavy metal ions and other toxic substances. If the water quality is not well understood, blind dosing may cause serious toxic and side effects to the entire denitrification system; in addition, the remaining sludge after anaerobic digestion is mainly used as Denitrification carbon source, this method can also improve denitrification efficiency, but the sludge after anaerobic treatment contains a large amount of phosphate, and chemical precipitation and phosphorus removal are required before being used as a denitrification carbon source, which not only increases operating costs but also Secondary pollution of the sewage treatment system will be caused by incomplete phosphorus removal or excessive dosage of chemicals

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