Biological treatment method for simultaneously removing carbon and nitrogen from sewage by controlling dissolved oxygen

Abstract

The invention discloses a biological treatment method used for realizing simultaneous removing of carbon and nitrogen in sewage via controlling dissolved oxygen. The biological treatment method comprises following steps: S1, sewage is delivered into a sewage treatment system provided with only one biological treatment tank, and the biological treatment tank is inoculated with domesticated active sludge, wherein after inoculation, the concentration of active sludge in the biological treatment tank is controlled to be 0.5 to 100g / L; S2, the concentration of dissolved oxygen in the sewage treatment system is controlled, and staged operation is carried out; S3, the total nitrogen, the total carbon, and the concentrations of negative and positive ions of inlet water and outlet water are detected; and S4, in seven days of continuous operation, the concentration of dissolved oxygen is maintained to be 0.1mg / L<=DO<1.0mg / L, TN removing ratio of the sewage treatment system on TOC of sewage of different carbon nitrogen ratio is measured. According to the biological treatment method, carbon nitrogen removing is completed in a same sewage treatment tank, the bacteria colony structure of anaerobic bacteria is controlled via controlling dissolved oxygen, ammoxidation is realized at first, and simultaneous removing of carbon and nitrogen in sewage is realized by denitrifying bacteria.

Description

technical field [0001] The invention relates to the field of environmental science and engineering technology, in particular to a biological treatment method for simultaneously removing carbon and nitrogen from sewage by controlling dissolved oxygen. Background technique [0002] The existing sewage treatment process is mainly composed of two parts: aerobic and anaerobic. In the aerobic process, organic carbon is decomposed by microorganisms into carbon dioxide and removed from water; at the same time, organic nitrogen is converted into inorganic nitrogen (mainly ammonia nitrogen), and the nitrification reaction oxidizes ammonia nitrogen into nitrite and nitrate nitrogen. In the anaerobic process, the final removal of nitrogen is realized, that is, the nitrite and nitrate generated in the aerobic process are gradually reduced by denitrifying bacteria, and finally nitrogen is released from the water body. The aerobic process mainly depends on aerobic bacteria, and the anaero...

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Problems solved by technology

[0011] (1) Biological treatment in the aerobic zone requires a large amount of aeration, which consumes a lot of electricity during actual operation and increases operating costs

[0012] (2) The carbon-nitrogen ratio of the two regions is unbalanced, resulting in insufficient carbon source for colonies in the anaerobic region

[0013] (3) The sudden change of dissolved oxygen leads to the instability of the mechanism of the reaction device

There is a sudden change point of dissolved oxygen concentration at the time of transition between the aerobic zone and the anaerobic zone. If the dissolved oxygen in the entire reaction device does not transition well between the two zones, it will cause the inactivation of aerobic bacteria and anaerobic bacteria, and then It will lead to the paralysis and inactivation of the entire sewage treatment system

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