A salinity resource recovery process for high-salinity wastewater

Abstract

The invention relates to a new technology for recycling salt resources from high-salt-containing waste water. The new technology is characterized by comprising the following steps: A) front-end treatment: treating high-salt-containing waste water with main components of sodium chloride and sodium sulfate by adopting a conventional front-end treatment method, so that the physical-chemical index meets the usage requirements of a follow-up selective electrodialysis device; B) selective electrodialysis, wherein the selective electrodialysis on one hand can separate liquor into sodium sulfate-rich liquor flow and a sodium chloride-rich liquor flow by utilizing the separation action of a selective zwitterion exchange membrane to monovalent and high-valence ions, on the other hand, the concentration action of electrodialysis to the liquor can be utilized; and C) crystallization treatment: leading the separated sodium sulfate-rich liquor flow to flow in a rear-end evaporation crystallization section, to realize recycling of purified water while obtaining sodium sulfate product salt with higher purity; and leading sodium chloride-rich liquor flow to flow in the rear-end crystallization section, to realize recycling of purified water while obtaining sodium chloride product salt with higher purity. The new technology realizes zero emission of high-salt-containing waste water and the effective recycling of salt, the method is simple, and the treatment cost can be lowered.

Description

technical field [0001] The invention relates to a water treatment technology, in particular to a zero-discharge treatment technology for high-salt waste water, in particular to a new process for salinity recovery of high-salt waste water. Background technique [0002] At present, as the national environmental protection policies and regulations become more stringent, all pollution-producing enterprises are forced to adopt new technologies and new processes to realize sewage treatment and reuse. For saline wastewater, while most of the water is recovered by conventional sewage treatment techniques, highly saline wastewater that is difficult to treat will be produced. Under the new policy, it is strictly forbidden to directly discharge this part of wastewater into the environment, because it will directly lead to an increase in the salinity of river water, bring serious pollution to soil, surface water, and groundwater, and damage the ecological environment. With the concept ...

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Problems solved by technology

[0005] The purpose of the present invention is to invent a new process for salinity recycling of high-salinity wastewater, aiming at the problems of low recycling rate of existing high-salt wastewater, great impact on the environment, and high treatment cost

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