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Method for releasing biological toxicity of mixed acid nitrified wastewater

A nitrification wastewater and biological toxicity technology, which is applied in chemical instruments and methods, oxidized water/sewage treatment, natural water treatment, etc., can solve the problems of large investment, complex system, and high cost of wastewater treatment, and achieve the reduction of biological toxicity and low cost The effect of operation and high stability

Active Publication Date: 2009-09-16
NANJING UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of the existing problems of mixed acid nitrification wastewater treatment: (1) The investment of imported technology is relatively large, the cost of wastewater treatment is high, and it is difficult to popularize and apply; (2) The efficiency of conventional technology is not high, and toxic and harmful substances are difficult to remove; (3) The system is relatively complex, the operation requirements are high, and the stability needs to be improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Nitrotoluene production (process is toluene mixed acid nitration) waste water (COD5000~7000mg / L, nitrobenzene concentration 500mg / L, aniline concentration 200mg / L, pH value 1.5~2.5, influent flow rate 10t / h) Put into the bulk iron (0.5% carbon content) packing bed, and the reaction residence time is 4h;

[0021] The effluent enters the oxidation tank, and chlorine dioxide solution is continuously added to the tank for a residence time of 4 hours. In order to improve the mixing effect, the tank is stirred by air.

[0022] Adjust the pH value of the effluent to 7.5, use polyacrylamide as a coagulant, and effluent after 5 hours of precipitation.

[0023] The concentration of COD in the effluent is 2000mg / L-2500mg / L, and the removal rate reaches 60%. From 0.1 before treatment to 0.41, after anaerobic + aerobic treatment, the effluent reaches the national first-level discharge standard.

Embodiment 2

[0025] Nitrobenzene production (process is nitration of benzene mixed acid) wastewater (COD~7000mg / L, nitrobenzene concentration 1000mg / L, aniline concentration 500mg / L, pH value 1.5~2.5, influent flow 50t / h) Put into the mechanical agitation reactor that zero-valent iron powder (containing carbon weight percentage is 2%) is housed, and the reaction residence time is 2.5h;

[0026] The effluent enters the oxidation tank, and the hydrogen peroxide solution with an oxidant amount of 1.5% is continuously added in the tank, and the residence time is 2 hours. In order to improve the mixing effect, air stirring is used in the tank.

[0027] Adjust the pH value of the effluent to 10, use polyacrylamide as a coagulant, and effluent after 5 hours of precipitation.

[0028] The concentration of COD in the effluent is about 2000mg / L, the removal rate reaches 70%, the removal rate of nitrobenzene and aniline concentration is above 95%, and the B / C ratio of wastewater increases from 0.07 b...

Embodiment 3

[0030] Wastewater from nitrobenzene production (COD~7000mg / L, nitrobenzene concentration 1000mg / L, aniline concentration 500mg / L, pH value 1.5~2.5, influent flow rate 200t / h) is fed into zero-valent iron powder (the carbon-containing weight percent is 5%) mechanical stirring reactor, and the reaction residence time is 1h;

[0031] The effluent enters the oxidation tower equipped with packing, and chlorine dioxide solution is continuously added to the tower, and the residence time is 2 hours.

[0032] Adjust the pH value of the effluent to 8.0, use polyacrylamide as a coagulant, and effluent after 3 hours of precipitation.

[0033] The concentration of COD in the effluent is about 2000mg / L, the removal rate reaches 70%, the removal rate of nitrobenzene and aniline concentration is above 95%, and the B / C ratio of wastewater increases from 0.07 before treatment to 0.40. After oxygen treatment, the effluent reaches the national first-level discharge standard.

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Abstract

The invention discloses a method for releasing biological toxicity of mixed acid nitrified wastewater, and belongs to the technical field of organic chemical wastewater treatment. The method comprises the following three steps: (1) zero-valent iron reaction, namely introducing high-concentration mixed acid nitrified wastewater into a reactor to carry out reduction reaction with zero-valent iron in the reactor; (2) advanced oxidation, namely adding oxidant into the wastewater subjected to the zero-valent iron reaction to carry out oxidation reaction under the condition of full mixing; and (3) coagulating sedimentation, namely adjusting the pH value of the oxidized wastewater to be weakly alkaline, adding coagulating agent into the wastewater to carry out full reaction and sedimentation, wherein the discharged water can flow into a biochemical system. The method can effectively reduce the biological toxicity of the wastewater to meet the requirement of subsequent biochemistry. By adopting the method, the removal rate of nitrobenzene and phenyl amine substances is more than 95 percent, the removal rate of COD is more than 50 percent, the BOD is improved by more than 80 percent, the ratio of B to D is improved to more than 0.4, and the biological toxicity is reduced greatly.

Description

technical field [0001] The invention relates to a method for treating organic chemical wastewater, in particular to a method for removing the biological toxicity of mixed acid nitrification wastewater. Background technique [0002] Mixed acid nitration is a very important chemical process. The main process is to use nitric acid as a nitrating agent and sulfuric acid as a catalyst to react with aromatic hydrocarbons to generate nitroaromatics. Common nitroaromatics include nitrobenzene, nitrotoluene, trinitrobenzene They are all important chemical raw materials, widely used in industries such as military industry, medicine, dyestuff and polyurethane materials. [0003] During the mixed acid nitrification process, a stream of wastewater with high chroma, complex composition and poor biodegradability is produced, called mixed acid nitrification wastewater, which contains a large amount of organic poisons such as nitrobenzenes, anilines, benzenesulfonic acids, phenols, etc., and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F1/72C02F1/70C02F1/52C02F1/76C02F103/36
Inventor 李爱民陆朝阳范俊戴建军陈金龙凌洪吉李业文杨尧汪海萍朱兆连姜笔存李汉雄俞守业闫蕾徐鑫煤
Owner NANJING UNIV
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