Method for realizing zero emission of dyeing wastewater with high salinity in printing and dyeing enterprises

Abstract

The invention discloses a method for realizing zero emission of dyeing wastewater with high salinity in printing and dyeing enterprises. The method comprises the following steps that: the wastewater enters a regulating reservoir first for homogenizing, and then enters a reaction tank, ferrous sulfate is added into the reaction tank to regulate the pH value and perform a coagulation reaction, effluent enters a sedimentation basin for precipitating after the reaction, supernate of the sedimentation basin is treated by an electrochemical reactor, enters a secondary sedimentation basin so as to remove scummings and dregs and enters an aeration tank for aerating, and the supernate is filtered by a manganese sand filter for deferrization after the aerating; the filtered effluent is treated by using an ultrafiltration membrane, concentrated water of the ultrafiltration membrane returns to the regulating reservoir, and fresh water enters a nanofilter membrane for treating; the fresh water outputted by the nanofilter membrane enters a reverse osmosis membrane, the outputted concentrated water returns to the regulating reservoir or is evaporated directly; and concentrated water of the reverse osmosis membrane enters an electrodialyzer, electrodialytic fresh water is refluxed to be used as inflow of the reverse osmosis membrane, and electrodialytic concentrated water enters an evaporator for evaporating. Vapor generated by evaporating can be used for printing and dyeing production, residues generated by the evaporating are used as solid wastes, and water pollutants are not discharged in the whole process.

Description

Technical field [0001] The invention belongs to the field of sewage treatment engineering, and relates to a method for the desalination and reuse of dyeing wastewater and achieving zero discharge. Background technique [0002] The textile printing and dyeing industry is a traditional industry of my country's national economy and a pillar industry of my country's export earnings. However, the textile printing and dyeing industry is also a major pollution source of industrial water pollutants in my country. According to statistics from the State Environmental Protection Administration, the total amount of printing and dyeing wastewater discharged by the printing and dyeing industry ranks fifth in the total discharge of various industrial departments in the country, and the environmental hazards are very serious. [0003] Printing and dyeing wastewater is the general term for wastewater discharged from various production links such as desizing, scouring, dyeing, bleaching, and finishi...

AI Technical Summary

Problems solved by technology

[0005] Evaporation technology is an effective technology to achieve zero discharge of wastewater, but the evaporation process is a phase change process, which consumes a lot of steam or electricity, and the operating cost is high

If the printing and dyeing wastewater, or just the high-concentration wastewater in the dyeing process, is directly evaporated, the cost is also difficult for enterprises to accept

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