Electroplating wastewater treatment method, treatment system and application

Abstract

The invention provides an electroplating wastewater treatment method which is characterized by sequentially including the steps: (1) pre-treating metal wastewater, organic wastewater, complex wastewater, cyanide-containing wastewater, nickel-containing wastewater, zinc-containing wastewater and chromium-containing wastewater to obtain pretreated water; (2) mixing and concentrating the pretreated water obtained in the step (1) to obtain high-salinity concentrated water and reused water; (3) mixing the high-salinity concentrated water obtained in the step (2) with the pretreated water obtained in the step (1), and performing biochemical treatment; (4) performing hyper-concentration on biochemical treatment water obtained in the step (3) to obtain ultra-high-salinity concentrated water; (5) evaporating and crystallizing the ultra-high-salinity concentrated water obtained in the step (4) to obtain reused water and a crystal substance. The method is simple in operation and stable in running, zero emission or low emission of comprehensive electroplating wastewater in electroplating production is achieved, and metal ions in the wastewater are recycled in a high-purity manner.

Description

technical field [0001] The invention relates to a wastewater treatment method and a treatment system, in particular to a zero-discharge treatment method and a treatment system for electroplating wastewater. Background technique [0002] Electroplating wastewater treatment often uses chemical precipitation method, electrolysis method, common ion exchange method and other treatment methods in the treatment process. However, the above treatment methods have certain limitations and cannot achieve zero emissions. [0003] Chemical precipitation is a commonly used method to treat electroplating wastewater. This method needs to add a large amount of acid and alkali, and at the same time, it needs to add ferrous sulfate and polyaluminum chloride, thereby increasing the salt content of the water discharge, and the residual metal ions in the water emissions are still difficult to meet standards. Therefore, due to the extremely low content of controlled substances stipulated in the w...

AI Technical Summary

Problems solved by technology

However, the above treatment methods have certain limitations and cannot achieve zero emissions.

[0003] Chemical precipitation is a commonly used method to treat electroplating wastewater. This method needs to add a large amount of acid and alkali, and at the same time, it needs to add ferrous sulfate and polyaluminum chloride, thereby increasing the salt content of the water discharge, and the residual metal ions in the water emissions are still difficult to meet

Therefore, due to the extremely low content of controlled substances stipulated in the wastewater discharge standard, excessive chemicals need to be invested to meet the discharge standard, which is costly, and the wastewater cannot be recycled as process water

In addition, the chemical sedimentation method cannot directly recover the metal ions in the wastewater, and will also generate a large amount of sludge, which contains a large amount of metal ions, and the sludge needs to be treated again, causing secondary pollution

[0004] The electrolysis treatment process is mature and the operation is stable. However, due to the extremely low content of controlled substances stipulated in the discharge standards, this treatment method consumes a lot of electricity when electrolyzing wastewater, and the treatment cost is high. It is easy to produce toxic gases and is difficult to treat. Discharge

[0005] Ordinary ion exchange method uses organic skeleton ion exchange resin, which can effectively remove various harmful ions in wastewater, and water can be reused at the same time, but the amount of resin required by this treatment method is large, the regeneration solution is difficult to treat, and a large amount of acid and alkali is consumed , the processing cost is high; and during the regeneration process of the resin, a large amount of resin is broken due to the regeneration, shrinkage and expansion of the resin, and the economy is not high

For example, reverse osmosis membrane is used to concentrate and treat electroplating wastewater, and at the same time, pure water is reused, but this process is only applied to the wastewater system treatment of a single high-valent ion, so its use has its limitations

[0006] It can be seen that there are many problems in various treatment methods for electroplating wastewater. Even if the existing equipment of each electroplating factory is fully utilized, most or all of the wastewater cannot be reused, and the valuable metals in the wastewater Cannot be effectively separated and recovered

Images