A kind of cyanogen-containing wastewater treatment method, treatment system and application

Abstract

The invention provides a method for treating cyanide-containing wastewater, which is characterized in that the treatment method comprises in sequence: (1) pretreating cyanide-containing wastewater to obtain pretreated water; (2) pretreating the pretreated water obtained in step (1) The treated water is subjected to biochemical treatment to obtain biochemically treated water; (3) the biochemically treated water obtained in step (2) is subjected to concentrated treatment to obtain concentrated treated high-salt concentrated water and reused water; (4) the concentrated treated water obtained in step (3) is Treat high-salt concentrated water for evaporation and crystallization to obtain recycled water and crystals; the standard for recycled water is: pH 6-8, conductivity ≤ 50, COD ≤ 30, turbidity ≤ 1; the method is simple, stable, and Low cost and high treatment efficiency, so as to achieve zero discharge or low discharge of cyanide-containing wastewater in electroplating production, and at the same time achieve higher purity recovery of various metal ions in wastewater.

Description

technical field [0001] The present invention relates to a wastewater treatment method and a treatment system, in particular to a treatment method for cyanide-containing wastewater in the electroplating industry, a system for treating cyanide-containing wastewater in the electroplating industry that has been used in the method and the method or the system in use Application in the treatment of cyanide-containing wastewater in the electroplating industry. Background technique [0002] The treatment of cyanide-containing electroplating wastewater often uses chemical methods, electrolysis methods, and ordinary ion exchange methods in the treatment process. The above treatment methods have certain limitations and cannot achieve zero discharge. Chemical method is a widely used method to deal with complex electroplating wastewater. In the production process, a large amount of acid and alkali need to be added. At the same time, ferrous sulfate and polyaluminum chloride need to be a...

AI Technical Summary

Problems solved by technology

The above treatment methods have certain limitations and cannot achieve zero emissions

Chemical method is a widely used method to deal with complex electroplating wastewater. In the production process, a large amount of acid and alkali need to be added. At the same time, ferrous sulfate and polyaluminum chloride need to be added, which increases the salt content of water discharge, and the residual water It is still difficult to meet the discharge standard of metal ions; due to the extremely low content of controlled substances stipulated in the wastewater discharge standard, excessive chemicals need to be invested in order to meet the discharge standard, the cost is high, and the waste water cannot be recycled as process water; while the electrolysis method The treatment process is mature and the operation is stable. However, due to the extremely low content of the controlled substance specified in the discharge standard, the electrolysis of wastewater consumes a lot of electricity, the treatment cost is high, and it is easy to produce toxic gases, which is difficult to treat and discharge to meet the standard; ordinary ion exchange method The use of organic skeleton ion exchange resin can effectively remove various harmful ions in wastewater, and at the same time, water can be reused, but the amount of resin is large, the regeneration solution is difficult to deal with, a large amount of acid and alkali needs to be consumed, and the treatment cost is high; and the resin is in the regeneration process. , due to resin regeneration, resulting shrinkage and expansion, a large number of resin cracks are caused, and the economy is not high

There are also some treatment methods that use reverse osmosis membrane to concentrate and treat electroplating wastewater, and at the same time reuse pure water, but this process cannot meet the process requirements, and its use has its limitations.

[0003] It can be seen that there are many problems in the various treatment methods for cyanide-containing wastewater. Even if the existing equipment of each electroplating plant is fully utilized, most or all of the wastewater cannot be reused, and the value of the wastewater in the wastewater Metals cannot be effectively separated and recycled

Images