Comprehensive electroplating wastewater treatment method and system and application thereof

Abstract

The invention provides a comprehensive electroplating wastewater treatment method. The comprehensive electroplating wastewater treatment method is characterized by including the steps of 1), pretreating comprehensive electroplating wastewater to obtain pretreated water; 2), subjecting the pretreated water obtained in the step 1) to biochemical treatment to obtain biochemically treated water; 3), subjecting the biochemically treated water obtained in the step 2) to concentration treatment to obtain concentration treated high-salt water and reuse water; 4), subjecting the concentrated treated high-salt water obtained in the step 3) to evaporation crystallization treatment to obtain the reuse water and crystal substances, wherein the standard of the reuse water is that the pH value is 6-8, the conductivity is smaller than or equal to 50, COD (chemical oxygen demand) is smaller than or equal to 30, and the turbidity is smaller than or equal to 1. The method is simple in operation, stable in running, low in cost and high in treatment efficiency; zero emission or low emission of the comprehensive electroplating wastewater in electroplating production is achieved, and meanwhile, metal ions in the wastewater are recovered in high purity.

Description

technical field [0001] The invention relates to a wastewater treatment method and a treatment system, in particular to a comprehensive electroplating wastewater treatment method and a treatment system. Background technique [0002] Comprehensive electroplating wastewater treatment often uses chemical precipitation, electrolysis, common ion exchange and other treatment methods in the treatment process. However, the above treatment methods have certain limitations and cannot achieve zero emissions. [0003] The chemical precipitation method is a method that is often used in the treatment of comprehensive 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 in the water. The emission of ions is still difficult to meet the standard. Therefore, due to the extremely low content of con...

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Problems solved by technology

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

[0003] The chemical precipitation method is a commonly used method to treat comprehensive 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 in the water Emissions of ions remain 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 the various treatment methods for comprehensive 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 value of the wastewater in the wastewater Metals cannot be effectively separated and recycled

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