Anaerobic-aerobic deep coupled method for treating high-concentration organic wastewater

Abstract

An anaerobic-aerobic deep coupled method for treating high-concentration organic wastewater comprises the following steps: crushing and screening organic waste, and feeding the slurry from filtrationinto an anaerobic reaction unit for anaerobic fermentation to obtain biogas and biogas slurry; subjecting the biogas slurry after the anaerobic reaction to a synchronous nitrification and denitrification process in an aerobic reaction unit for nitrogen removal; and returning part of effluent from the aerobic reaction unit to the anaerobic reaction unit to be fully diluted and mixed with the raw slurry of organic waste for anaerobic reaction, while discharging the other part of the effluent into next treatment process or discharging the rest effluent on standard. According to the invention, theeffluent from the anaerobic reaction is discharged into the aerobic unit, and the DO value of the water in the aerobic unit is controlled to complete nitrogen removal; then, the effluent from the aerobic reaction is returned to the anaerobic unit again at a controlled reflux ratio for circular reaction; and therefore, the biogas production rate of anaerobic reaction can be increased, while the water quality of the effluent from the aerobic reaction can be higher.

Description

technical field [0001] The invention relates to a method for anaerobic-aerobic deep coupling treatment of organic wastewater with high suspended matter, belonging to the technical field of sewage treatment. Background technique [0002] Anaerobic reactors are generally preferred for wastewater treatment and resource utilization, but because the reactants often contain a large amount of nitrogen-containing substances, during the anaerobic fermentation process, a large amount of protein will be transformed and decomposed, and a large amount of free ammonia nitrogen will be released, resulting in the accumulation of ammonia nitrogen , the ammonia nitrogen concentration often reaches above 2000mg / L. According to research, an important nutritional factor affecting the growth of methanogens is ammonia nitrogen. When the concentration of ammonia nitrogen is 50-200 mg / L, it is conducive to the anaerobic reaction; but when the concentration of ammonia nitrogen reaches 2000 mg / L or mo...

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Problems solved by technology

[0005] DO (dissolved oxygen in water) problem: the aerobic process generally requires a large amount of oxygen. For example, the dissolved oxygen in the aerobic section of the A / O process is controlled above 2.0mg / L, while in the anaerobic reaction, especially the methanogenic stage, due to Methanogens lack superoxide dismutase and are sensitive to O 2 very sensitive

If the effluent of the traditional aerobic biochemical process is directly recycled to the anaerobic unit, a large amount of O 2 It will interact with some active groups in the cells of methanogens, leading to the disintegration of important enzyme systems; at the same time, O 2 The superoxide anion free radicals produced will also cause lethal damage to cells, which will eventually lead to the failure of anaerobic reactions;

[0006] Nitrate nitrogen problem: It is generally believed that the anaerobic environment is a water body environment where there is no nitrate nitrogen or a very small amount, but most aerobic processes can only do a good job in the conversion process of ammonia nitrogen to nitrate nitrogen, but cannot complete the conversion process of nitrate nitrogen to nitrogen conversion

That is to say, once the aerobic effluent returns to the anaerobic unit, it will carry a large amount of nitrate nitrogen, directly destroying the anaerobic environment, so that the heterotrophic bacteria in the reactor become the dominant species, seriously affecting the anaerobic reaction process, and even failure of anaerobic reaction

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