Method for treating high-solid-content organic wastewater by anaerobic-aerobic deep coupling

Abstract

The invention relates to a method for treating high-solid-content organic wastewater by anaerobic-aerobic deep coupling. The method comprises the following steps: crushing and screening organic wastes, adding a slurry liquid obtained by filtration into an anaerobic reaction unit, and carrying out anaerobic fermentation to obtain biogas and biogas slurry; introducing anaerobic outlet water into a solid-liquid separation unit for solid-liquid separation, and enabling separated biogas residues to return into the anaerobic reaction unit through a sludge backflow pump; enabling separated biogas slurry to enter an aerobic reaction unit, and removing nitrogen through a synchronous nitrification and denitrification process; and enabling part of outlet water of the aerobic reaction unit to flow back to the anaerobic reaction unit and undergo full dilution and mixing with organic waste raw slurry liquid for an anaerobic reaction, and enabling the other part of the outlet water to enter a next treatment process or be discharged after reaching the standard. According to the method, the anaerobic outlet water enters the solid-liquid separation unit, suspended solids are separated out, outlet water enters the aerobic reaction unit, the DO value in the water body of the aerobic reaction unit is well controlled, denitrification is completed, then a backflow ratio of aerobic outlet water is controlled and part of the aerobic outlet water returns to the anaerobic reaction unit again, the reaction is circulated, the anaerobic biogas production rate is increased, and meanwhile the water quality of the aerobic outlet water is higher.

Description

technical field [0001] The invention relates to a method for anaerobic-aerobic deep coupling treatment of organic wastewater with high solid content, and belongs to the technical field of sewage treatment. Background technique [0002] Anaerobic reactors are generally preferred for waste water treatment and resource utilization. However, since 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 ammonia nitrogen. Accumulated, 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 more, i...

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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

[0007] In addition, for sewage with high suspended solids (solid content > 3%), after the anaerobic reaction, the fine particles and suspended matter in the mixed solution are anaerobic products, which will be mixed with other reactants and good after directly entering the aerobic biochemical tank. Aerobic and facultative species compete for O 2 , resulting in insufficient oxygen supply in the biochemical pool, destroying the aerobic environment, thereby affecting the efficiency of the aerobic reaction, therefore, it is necessary to reduce the content of suspended matter in the aerobic influent

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