Deep treatment method and device of coking wastewater

Abstract

The invention discloses a deep treatment method of coking wastewater. The method comprises the following steps of firstly adjusting pH of wastewater and filtering; reacting in a first-stage ozone reaction tower and a second-stage ozone reaction tower; carrying out ozonolysis in an enclosed intermediate water tank; treating in an aeration biological filtering tank; and introducing non-decomposed ozone into a tail gas absorber or destroyer. A treatment device mainly comprises a mixing sedimentation tank, the first-stage ozone reaction tower, the second-stage ozone reaction tower, the aeration biological filtering tank and conveying pipes, wherein the conveying pipe between the mixing sedimentation tank and the first-stage ozone reaction tower is connected with a multi-medium filter; and the conveying pipe between the second-stage ozone reaction tower and the aeration biological filtering tank is connected with the enclosed intermediate water tank and the tail gas absorber or destroyer is connected with two ozone reaction towers and the enclosed intermediate water tank. By combining ozone catalytic ozonation and the aeration biological filtering tank, non-biodegradable organic substances in wastewater are oxidized by virtue of ozone and mineralized or partially oxidized into easily degradable small molecular organic substances and the small molecular organic substances can be subjected to subsequent treatment by virtue of cheap organisms in the aeration biological filtering tank.

Description

technical field [0001] The invention relates to a wastewater treatment method and a treatment device, in particular to a coking wastewater advanced treatment method and device. Background technique [0002] Coking wastewater is a recognized industrial wastewater that is difficult to biodegrade. The difficulty lies in the poor biodegradability of the wastewater. In addition to inorganic pollutants such as ammonia, cyanide, and thiocyanate, it also contains impurities such as phenols, naphthalene, pyridine, and quinoline. Cyclic and polycyclic aromatic compounds (PAHS) are difficult to biodegrade. These substances can have long-term effects on the environment, and some of them have been confirmed as carcinogens by research. In addition, high concentrations of ammonia nitrogen have a strong inhibitory effect on microbial activity. Biodegradation Nitrogen does not work well. At present, the treatment of coking wastewater generally adopts biological treatment methods based on A / ...

AI Technical Summary

Problems solved by technology

[0002] Coking wastewater is a recognized industrial wastewater that is difficult to biodegrade. The difficulty lies in the poor biodegradability of the wastewater. In addition to inorganic pollutants such as ammonia, cyanide, and thiocyanate, it also contains impurities such as phenols, naphthalene, pyridine, and quinoline. Cyclic and polycyclic aromatic compounds (PAHS) are difficult to biodegrade. These substances can have long-term effects on the environment, and some of them have been confirmed as carcinogens by research. In addition, high concentrations of ammonia nitrogen have a strong inhibitory effect on microbial activity. Biodegradation Nitrogen is not effective

At present, the treatment of coking wastewater generally adopts biological treatment methods based on A / O or A / O / O, A / A / O, O / A / O and other biologically enhanced processes after A / O process improvement. The biological treatment method is often supplemented by coagulation and sedimentation treatment, which barely meets the discharge standard requirements. In addition, due to the high cost of advanced treatment, many coking plants in China are discouraged, so most coking wastewater is directly discharged after secondary treatment

However, although the wastewater has undergone the above-mentioned treatment, there are still many toxic and harmful substances (cyanide, COD and heterocyclic compounds, etc.) in it, which cannot meet the discharge standards allowed by the state.

[0003] In 2012, the country promulgated and implemented the "Coking Chemical Industry Pollutant Discharge Standard" (GB16171-2012), which requires the discharge requirements of existing coking enterprises to implement the standards in Table 2 from January 1, 2015, in which the COD emission concentration in Table 2 is required to be less than 80mg / L, while the current biochemical treatment process commonly adopted in the coking industry cannot reach the level of effluent COD≤80mg / L due to the limitation of the process itself. Therefore, under the huge pressure of environmental protection, coking enterprises must adopt appropriate advanced treatment methods

The use of the three-stage superposition method strengthens the problem of ozone mass transfer in the solution and improves the utilization rate of ozone; however, in reality, the effluent of the conventional biochemical stage carries a large amount of suspended solids and the soluble ozone in the water is poisonous to the microorganisms of the biological activated carbon reactor. Function, etc. have not been dealt with in further detail

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