Method for treating and recycling high-salinity industrial wastewater

Abstract

The invention provides a method for treating and recycling high-salinity industrial wastewater. The method comprises the following steps: adding an organic solvent which is mutually soluble with water into the high-salinity industrial wastewater, standing, separating out salt precipitate, filtering, evaporating at a low temperature until the concentration of Cl<-> is less than 3g / L, and recycling. According to the method, the polarity of water is changed, the solubility of salts in the water is greatly reduced, the salt precipitate is separated out, the separated mixed solvent is evaporated and recycled at the low temperature, the concentration of Cl<-> remaining in the water is smaller than 3 g / L, and the purpose of recycling is achieved.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a method for treating and recycling high-salinity industrial wastewater. Background technique [0002] High-salt wastewater refers to wastewater with a total salt content of at least 1%, which mainly comes from chemical plants and oil and natural gas collection and processing. This wastewater contains a variety of substances (including salt, oil, organic heavy metals and radioactive substances). Salt wastewater is produced in a wide range of ways, and the amount of water is increasing year by year. The environmental impact of removing organic pollutants in saline wastewater is crucial. Biological treatment is used, and high-concentration salts have an inhibitory effect on microorganisms. Physicochemical treatment requires large investment and high operating costs, and it is difficult to achieve the expected purification effect. [0003] Distillation is one of the ...

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Problems solved by technology

[0004] Biological method is currently the most widely used wastewater treatment method in China. It mainly uses the metabolism of microorganisms to complete the degradation of organic matter in wastewater. It has the advantages of wide application range, large treatment capacity, and low operating cost. It is suitable for 5000mg / L organic wastewater, but the wastewater of dye intermediates is not suitable for biological treatment due to its very high salt content

[0005] Chemical oxidation technology generally completes the oxidation and decomposition of organic matter in water under the action of a catalyst. For example, wet catalytic oxidation technology needs to add a catalyst to complete the oxidation of organic matter under high pressure. Shortcomings

[0006] At present, industrial wastewater in the chemical and metallurgical industry contains KCl, NaCl, and NH 4 Cl and other salts, of which the total Cl - When the content is greater than 40g / L, it cannot be directly discharged or reused, causing great waste

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