Salt-separation zero-discharge system for high-salt industrial wastewater

Abstract

The invention discloses a salt-separation zero-discharge system for high-salt industrial wastewater and belongs to the field of water treatment. The high-salt industrial wastewater enters a first-stage salt separation system after subjected to chemical softening through a precise pretreatment unit and concentration desalination through a membrane separation concentration unit, nanofiltration produced water and nanofiltration concentrated water which are produced after first-stage salt separation are concentrated by a high-pressure flat membrane system and conveyed to an advanced oxidation system of a crystallization recycling unit for oxidation treatment respectively, and obtained products are supplied to a second-stage salt separation system; the second-stage salt separation system adopts two multiple-effect evaporation or MVR systems or adopts a multiple-effect evaporation or MVR system and a freezing crystallization system. The salt-separation zero-discharge system has the beneficial effects as follows: the two stages of salt separation systems supplement each other, various inorganic salts are separated completely, and production of mixed abraum salts is reduced to the greatest extent; first-stage salt separation serves as guarantee of second-stage salt separation, the salt separation efficiency of the whole system can be guaranteed under the condition of larger fluctuation of quality of inflow water, and the impact load resistance of the system is enhanced.

Description

technical field [0001] The invention relates to a two-stage salt separation treatment process for high-salt industrial wastewater, which belongs to the field of water treatment in environmental protection. Background technique [0002] All kinds of industrial and mining enterprises represented by the coal chemical industry consume a huge amount of water and produce a large amount of wastewater. The water quality is complex, with high concentrations of pollutants and high salt content. The wastewater discharged by these enterprises can be collectively referred to as high-salt industrial wastewater. At present, high-salt industrial wastewater can meet the reuse requirements after pretreatment, biochemical treatment, and reuse water treatment. However, since the water recovery rate of the reuse water system is only 80%, the remaining 20% ​​of high-concentration brine has nowhere to go. It can be drained, so seeking high-salt industrial wastewater treatment technology with high...

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Problems solved by technology

[0008] Due to the limitations of various factors such as the current domestic technical level, equipment investment, operating cost, and operational stability, high-salt industrial wastewater cannot be effectively separated and crystallized, and the produced sodium chloride, sodium sulfate, and sodium nitrate are difficult to separate and crystallize. Meet industrial reuse standards, and the investment and operating costs remain high, which seriously restricts the development of "zero discharge" technology for high-salt industrial wastewater

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