High-salt wastewater treatment system and process for improving sodium chloride recycling rate

Abstract

The invention discloses a high-salt wastewater treatment system for improving the sodium chloride recycling rate. The system comprises an adjusting tank, a first-stage nanofiltration membrane device,a sodium sulfate evaporative crystallization unit, an RO membrane device, an RO concentrated water tank, a sodium chloride evaporative crystallization unit, a second-stage nanofiltration membrane device, a mother liquor mixing tank, a dosing tank, a filtering device and an impure salt evaporative crystallization unit. The water resource is saved, the environment is protected, salt in the high-saltwastewater is recycled, and the economic benefit of an enterprise is improved. The invention further discloses a high-salt wastewater treatment process for improving the sodium chloride recycling rate. The high-salt wastewater treatment process comprises the following steps: 1, first-stage nanofiltration salt separation; 2, reverse osmosis filtration; 3, sodium trisulfate crystallization and sodium chloride crystallization; 4, mixing and dosing; 5, filtering to remove silicon; 6, second-stage nanofiltration salt separation; 7, crystallization of impure salts. The recycling rate of sodium chloride is increased, and the problems of high sludge yield, high medicament addition amount and low medicament cost caused by traditional methods are avoided.

Description

Technical field: [0001] The invention relates to the field of waste water treatment, in particular to a high-salt waste water treatment system and a process thereof for improving the resource utilization rate of sodium chloride. Background technique: [0002] Coal chemical enterprises will produce a large amount of high-salt wastewater during production and operation. High-salt wastewater has the characteristics of complex composition, large fluctuations in water quality and quantity, and high salt content. At present, most of my country's coal chemical enterprises are concentrated in the western region with a fragile ecological environment. There is no The sewage receiving body does not have the conditions for the discharge of waste water, and the direct discharge of such high-salt waste water will also cause waste of sodium salt resources, so it must be treated before it can be discharged. [0003] At present, nanofiltration and salt separation are usually used to treat suc...

AI Technical Summary

Problems solved by technology

However, due to the relatively high content of chloride ions and sulfate ions in such high-salt wastewater, there will be a certain amount of chloride ions in the concentrated nanofiltration water obtained after nanofiltration treatment, and there will also be a certain amount of sulfate ions in the nanofiltration product water. The purity of the sodium chloride crystalline salt and sodium sulfate crystalline salt finally obtained is not high, it is difficult to reach the standard for external sale, and chloride ions cannot be fully recovered, resulting in a low resource utilization rate of sodium chloride, which is not conducive to enterprises economic production of

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