How to discharge high concentration organic wastewater?

Rewrite: High-concentration organic wastewater is from the production process in many fields, such as the chemical industry, pharmaceutical industry, printing and dyeing, paper making, food processing, etc., they will discharge high-concentration organic wastewater, which is a major difficulty in industrial wastewater treatment, and it is difficult to reach the discharge standard through simple wastewater treatment methods.

It is difficult to treat for several reasons: the high concentration of organic matter; Contains more biodegradable substances; High salt content; The effluent water quality is unstable.

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Have done a lot of high-concentration organic wastewater treatment cases, share two more common cases: chemical wastewater and pharmaceutical wastewater. If you like, like, follow, bookmark.

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High concentration organic wastewater treatment case: chemical wastewater
The high-concentration organic wastewater discharged by chemical enterprises is mainly rich in aromatic compounds and heterocyclic compounds with high organic content, and a large part of it is difficult to biodegrade and difficult to treat.

One case is that there are two streams with COD concentrations of more than 10,000 mg/L (polymerized wastewater and esterification wastewater), and the amount of water is small. They need to go through the pretreatment process, first stabilize the COD concentration at 6000-8000mg/L, improve the biodegradability, and then degrade it through the biochemical treatment process.

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① The pretreatment process includes three kinds of physical method, chemical method and physical and chemical treatment method.

At the front end, physical methods such as grease trap, grating and regulating pool are used to remove the substances that can affect the subsequent treatment and adjust the water quantity and quality; The chemical method is "micro-electrolysis + Fenton", under acidic conditions, the removal of macromolecular organic matter and refractory organic matter in it, the general COD removal rate reaches about 40%, the internal biodegradability is improved, and the B/C ratio exceeds 0.3; Subsequently, the iron and suspended matter remaining in the wastewater are removed by the "coagulation precipitation method", and the effluent can enter the subsequent biochemical treatment process.

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② Biochemical treatment process includes anaerobic biological treatment method and aerobic biological treatment method.

At present, anaerobic biological treatment is the mainstream method for the treatment of high-concentration organic wastewater. Not only can most of the organic matter be removed when the organic concentration is very high, but also the macromolecular pollutants in the wastewater can be degraded, and the effluent quality is conducive to the subsequent aerobic biological treatment. The UASB reactor applied in this project is a mature anaerobic reactor. Because the wastewater after anaerobic biological treatment fails to meet the discharge standard and the effluent COD concentration reaches 1000mg/L, it needs to be degraded by aerobic biological treatment, and the organic matter is decomposed into carbon dioxide, water and other substances. The project adopts "multi-stage biological contact oxidation method", which has high impact resistance load and small sludge production.

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③ The advanced treatment process adopts "reaction tank + sedimentation tank".

The function of the advanced treatment process is to control the pollutants again. The COD concentration of the project has reached the discharge standard (COD concentration is less than 300mg/L). We use the way of "coagulation reaction + precipitation" to remove the suspended matter in it.

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High concentration organic wastewater treatment case: pharmaceutical wastewater
There are many classifications of pharmaceutical wastewater, such as chemical synthesis pharmaceutical, biological pharmaceutical, Chinese medicine pharmaceutical, etc., their organic concentration is quite high.

The case of our project is "Chinese medicine pharmaceutical wastewater treatment project", the main pollutants are organic matter, suspended matter, chroma, etc., there are a lot of suspended matter, insoluble organic matter and other substances in it, need to be removed first.

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① We use "grid, regulating tank, sedimentation tank, reaction tank, air flotation device, etc." as its pretreatment process. The main purpose is to remove most of the suspended matter and part of the organic matter in the pharmaceutical wastewater, the effluent becomes clear, and the impact of these substances on the subsequent biochemical treatment process is reduced.

② Biochemical treatment process adopts the combination of "anaerobic, anoxic and aerobic". The anaerobic biological treatment adopts "two-stage UASB reactor", the COD concentration in it is as high as 5000mg/L, which can be removed by the anaerobic reactor, the effluent COD concentration is less than 800mg/L, and the nitrogen-containing organic matter in it can be degraded - anaerobic ammoniation, which can achieve many goals with one stone.

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Anoxic + aerobic is a common biological nitrogen removal method, mainly composed of ammoniation, nitrification and denitrification, which can not only remove organic matter, but also remove ammonia nitrogen pollutants in it, which can meet the emission standards.

③ The advanced treatment process adopts sand filtration, etc., to ensure that organic matter, ammonia nitrogen, suspended matter, etc., can meet the emission standards.

The two cases of high concentration organic wastewater treatment are difficult, and it is necessary to combine the situation and adopt the corresponding wastewater treatment methods to form a wastewater treatment system, and stabilize it to the discharge standard to solve the wastewater problem.