Decoloration method and system for electroplating wastewater

Abstract

The invention belongs to the field of wastewater treatment, and particularly discloses a decoloration method and system for electroplating wastewater. According to the method, a certain quantity of strong reducing agent systems NaBH4 / NaHSO3 at certain proportions is added into final settlement tank effluent with a pH (potential of hydrogen) value of 7 in the electroplating wastewater, the mixture is uniformly stirred to stabilize the pH, a dilute sulphuric acid solution is added to adjust the pH to 7.0-8.0, wastewater containing resist salt is treated to be transparent and colorless in 1-10 minutes, and color reversion phenomenon is not caused during natural placement or after oxidizing agents such as sodium hypochlorite and the like are added. The treatment system based on the decoloration method for electroplating wastewater comprises a preparation chamber, a NO.1 reaction tank, a NO.2 reaction tank, a pH adjusting tank and the like, wherein the preparation chamber comprises a NaBH4 solution (containing 10%-40% of NaOH) preparation bucket, a NaHSO3 solution preparation bucket, a reaction system preparation bucket, a sulfuric acid storage bucket and a liquid caustic soda storage bucket. The method and the system have the characteristics of high electroplating wastewater decoloration efficiency, low probability of color reversion and the like.

Description

Technical field [0001] The invention relates to a decolorization treatment technology for electroplating wastewater, in particular to a method and system for decolorizing electroplating wastewater containing anti-dyeing salts. Background technique [0002] The composition of electroplating sewage is complex, which mainly comes from pre-treatment sewage of plating parts, coating rinsing water, post-plating treatment sewage and electroplating waste liquid. According to its pollutant characteristics, it can be divided into pre-treatment oily sewage, chromium-containing sewage, cyanide-containing sewage, other heavy metal-containing sewage, and acid-base sewage. Electroplating rinsing sewage usually contains cyanide, hexavalent chromium, copper, nickel, zinc and other toxic substances. If it is discharged without treatment or only after simple treatment, it will pose a great threat to the environment. [0003] At this stage, as our country pays more and more attention to environmenta...

AI Technical Summary

Problems solved by technology

The standard removal technology of heavy metal ions, cyanide and COD and other conventional pollutants has gradually matured. However, the problem of chromaticity of electroplating wastewater has been difficult to solve

At present, after the electroplating wastewater is treated by the previous process, the conventional detection indicators basically meet the standards, but the effluent will always turn yellow.

Moreover, it is difficult to decolorize after decolorization by existing methods and technologies such as chlorine oxidants and advanced oxidation technology, or the phenomenon of color reversion occurs soon after decolorization, and the chromaticity of the outlet water is difficult to reach the standard, and these methods use a large amount of chemicals , so it is difficult to meet the requirements in terms of technical feasibility and economic feasibility

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