Neutralization precipitation method, oxidation method, reduction method and so on are commonly used in electroplating wastewater treatment, but these methods also have corresponding shortcomings. The improved chemical precipitation method adopted by Espex Environmental Protection to treat electroplating wastewater has the advantages of small floor area, stable operation, simple operation and maintenance, etc. The treatment and discharge of electroplating wastewater is a difficult problem faced by many electroplating enterprises. We hope to help more enterprises reach the environmental protection standard.
During plating, the coated metal or other insoluble materials are used as anode, the workpiece to be plated is used as cathode, and the cations of the coated metal are reduced on the surface of the workpiece to be plated to form a coating. In order to eliminate the interference of other cations and make the coating even and firm, it is necessary to use the solution containing the plating metal cations as the plating solution to keep the concentration of the plating metal cations unchanged. The purpose of electroplating is to coat the base material with metal coating to change the surface property or size of the base material. Electroplating can enhance the corrosion resistance of metals (most of the coated metals are corrosion resistant metals), increase hardness, prevent abrasion, improve conductivity, smoothness, heat resistance and beautiful surface.
Modern wastewater treatment technology can be divided into primary wastewater treatment, secondary wastewater treatment and tertiary wastewater treatment according to the treatment degree.
Primary treatment of wastewater:
It is mainly used to remove suspended solid pollutants in wastewater, and most physical treatment methods can only meet the requirements of primary treatment. After primary treatment, BOD of electroplating wastewater treatment can generally be removed by about 30%, and industrial wastewater treatment equipment cannot meet the discharge standard. The primary treatment belongs to the pretreatment of secondary treatment.
Secondary treatment of wastewater:
It is mainly used to remove organic pollutants (BOD, COD) in colloid and dissolved state in wastewater, with a removal rate of more than 90%, Electroplating wastewater treatment equipment Make the organic pollutants meet the discharge standards.
Tertiary treatment of wastewater:
Further treatment of refractory organics, nitrogen, phosphorus and other soluble inorganic substances that can lead to eutrophication of water bodies. The main methods include biological nitrogen and phosphorus removal, coagulation sedimentation, sand rate, activated carbon adsorption, ion exchange and electroosmosis analysis.
At present, there are three main treatment methods for heavy metal wastewater: the first is chemical method, which removes heavy metal ions through chemical reaction, including chemical precipitation method, chemical reduction method, electrochemical method and macromolecule heavy metal catcher method. The second physical method is the method of separation by adsorption and concentration without changing the chemical form of heavy metal ions, including adsorption, solvent extraction, evaporation and solidification, ion exchange and membrane separation. The third type is biological method, which mainly uses the flocculation, absorption, accumulation and enrichment of microorganisms or plants to remove heavy metals, including biological flocculation, phytoremediation and biosorption. This paper introduces the application and research progress of the above methods in heavy metal wastewater, in order to provide a theoretical reference for the treatment of heavy metal pollution in water bodies.
