Electroplating wastewater treating and recycling process and system

Abstract

The invention discloses an electroplating wastewater treating and recycling process and system which are designed especially for solving the problems that the cost of the process for pretreating the electroplating wastewater is high, the sludge quantity is high, and the recovery rate of a film system is low in an existing chemical method. The electroplating wastewater recycling process comprises the following steps: adsorbing nickel-containing wastewater through resin to recover nickel salt; treating pickling waste liquid by electrodialysis to recover acid and then mixing with acid-alkali wastewater; transferring into an adjusting tank together with cyanide-containing wastewater subjected to alkaline second-stage cyanide breaking; enabling the water quality and volume to be uniform; transferring into a neutralizing tank; adding alkali to adjust pH (Potential of Hydrogen) to reach neutral value; then feeding into a film treating system in the combination of first-stage nanofiltration and second-stage reverse osmosis, wherein the water produced by reverse osmosis is recovered into an electroplating workshop, and the concentrated water produced by nanofiltration is recovered into the neutralizing tank; performing second-stage reverse osmosis on the concentrated water subjected to first-stage reverse osmosis; and transferring the concentrated water subjected to second-stage reverse osmosis into an efficient evaporator to evaporate. By adopting the process and system, the nickel and acid resources can be effectively recovered, the recovery rate of wastewater can be greatly raised, and the operation stability of the film system also can be greatly improved.

Description

technical field [0001] The invention relates to the field of electroplating wastewater treatment, in particular to an electroplating wastewater treatment and reuse process and system. Background technique [0002] The electroplating industry is an important processing industry and process-producing industry with strong versatility, wide use, cross-industry, and cross-department. Due to the use of a large amount of toxic and harmful chemicals such as strong acid, strong alkali, heavy metal solution, and cyanide, the electroplating industry has become one of the three major polluting industries in the world today. According to relevant statistics, there are more than 20,000 electroplating enterprises in my country, which discharge 400 million tons of wastewater into the environment every year, accounting for about 10% of the total domestic wastewater discharge and 10% of the total industrial wastewater discharge. 20%. The discharge of electroplating wastewater has caused the ...

AI Technical Summary

Problems solved by technology

Generally, electroplating wastewater needs to be pretreated before entering the membrane system. The existing technology for pretreatment of heavy metal wastewater and pickling wastewater is flocculation and sedimentation after adding a large amount of chemicals, which will not only generate a lot of chemical pollution sludge, which increases the treatment cost, and also greatly increases the salt content of the comprehensive wastewater entering the membrane system, which greatly affects the recovery efficiency of the membrane system

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