Micro-aeration nitrification combined with sludge fermentation coupled with denitrification method to treat domestic sewage with low carbon-nitrogen ratio

Abstract

A micro-aeration nitration combined sludge fermentation and denitrification coupled method for processing domestic sewage with low carbon nitrogen ratio belongs to the field of sewage and sludge processing. A device comprises a raw water pit, a mud storage tank, a main reactor, a water drain tank, an air compressor, a sludge discharge tank and an automatic control system. A stirrer, a temperature control device, a gas flowmeter and an aeration device are arranged on the main reactor. The method is as follows: during initial operation, discharged sludge of a residual sludge fermentation system is inoculated; during each periodic operation, residual sludge and domestic sewage which are discharged from an urban sewage biological denitrification system are injected into the main reactor; ammonia nitrogen in a mixed liquor undergoes a nitratlon reaction to be converted to nitrite nitrogen; and furthermore, an internal carbon source generated by sludge fermentation is used to carry out a denitrification reaction. According to the invention, micro-aeration is adopted in the stage of nitration, and there is no need to add an external carbon source in the stage of denitrification. Finally, the purpose of realizing development of an internal carbon source in sludge, a nitratlon reaction and a fermentation coupled denitrification reaction in a same reactor is achieved.

Description

technical field [0001] The invention relates to a method for treating low-carbon-nitrogen ratio domestic sewage with micro-aeration nitrification combined with fermentation coupled with denitrification, and belongs to the technical field of sewage biological treatment. The process is suitable for the enhanced nitrogen removal biological treatment of urban domestic sewage with low carbon-to-nitrogen ratio (COD mass concentration / total nitrogen mass concentration, C / N). Background technique [0002] With the increasing eutrophication of water bodies, nitrogen pollution has aroused people's attention. At the same time, the emission standards for nitrogen are becoming increasingly stringent. In the Discharge Standards of Pollutants for Urban Sewage Treatment Plants (GB18918-2002) promulgated by my country in 2002, the first-level A discharge standard for nitrogen is less than 5 mg / L for ammonia nitrogen and less than 15 mg / L for total nitrogen. However, the common problem of l...

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Problems solved by technology

This fermentation-elutriation method has the following disadvantages: 1. Since the mixed sludge is in an anaerobic environment for a long time, the viscosity of the sludge increases and it is difficult to separate the sludge from water; 2. It is difficult to avoid the occurrence of methane-producing reactions in the complete anaerobic fermentation process , and the process of producing methane will consume a large amount of fermentation products; 3. Since the elutriation efficiency is generally low, if you want to increase the dissolution rate of volatile fatty acids (Volatile Fatty Acid, VFA) in the liquid phase, you need to increase the amount of elutriation water and elutriation. 4. Due to the high ammonia nitrogen and phosphate released during the fermentation process, the influent load will increase when the fermentation broth is injected into the subsequent treatment unit

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