Wastewater treatment in the PCB circuit board industry
The information comes from:the Internet posted on:2023-04-19
There are chemical methods (chemical deposition method, ion exchange method, electrolysis method, etc.) and physical methods (various analytical methods, filtration methods, electrodialysis, reverse osmosis, etc.) for PCB occupational wastewater treatment. Chemical method is to convert pollutants in wastewater into easily separable objects (solid or gas), while physical method is to enrich pollutants in wastewater or separate easily separable objects from wastewater to meet discharge standards. There are the following methods both domestically and internationally:
1、 Decanting method
In fact, the analytical method is a filtration method, which is a physical method in the treatment of PCB occupational wastewater. The washing water containing copper shavings discharged by the deburring machine can be filtered and removed after being processed by an analyzer. The effluent filtered by the analyzer can be reused as cleaning water from the burr machine.
2、 Chemical method
Chemical methods include redox method and chemical deposition method. The oxidation-reduction method is the use of oxidants or reducing agents to convert harmful substances into harmless or easily precipitated and separated substances. The redox method is often used for cyanide and chromium wastewater in circuit boards.
3、 Chemical deposition ion exchange method
Chemical deposition treatment of high concentration circuit board wastewater is difficult to meet discharge standards and is often combined with ion exchange method. Firstly, the chemical deposition method is used to treat high concentration circuit board wastewater, reducing its heavy metal ion content to 5mg/L. The ion exchange method is used to reduce the heavy metal ions to the discharge standard.
4、 Electrolytic ion exchange method
In the professional wastewater treatment method of PCB, the electrolysis method can reduce the content of heavy metal ions in high concentration circuit board wastewater, with the same intention as the chemical deposition method. But the disadvantage of electrolysis method is that it is only useful for high concentration heavy metal ion treatment, with a decrease in concentration, a significant decrease in current, and a significant decrease in efficiency; High power consumption, difficult to promote; The electrolysis method can only handle a single metal. The electrolytic ion exchange method is a waste liquid from copper plating and etching, and other wastewater should be treated using other methods.
5、 Chemical method - membrane filtration method
After chemical pre-treatment of PCB professional enterprise wastewater, harmful substances can be deposited by filterable particles (diameter>0) μ）， By filtering through membrane filtration equipment, the emission standards can be met.
6、 Gas agglutination electrofiltration method
In the treatment methods of PCB occupational wastewater, the gas coagulation electric filtration method is a new chemical free wastewater treatment method announced in the United States in the 1980s, which belongs to the physical treatment method of printed circuit board wastewater. It consists of three parts. The sensitive word is an ion gas generator, where air is sucked into the generator and can change its chemical structure through an ion magnetic field to become highly active magnetic oxygen ions and nitrogen ions. The gas is introduced into the wastewater using jet equipment to oxidize and aggregate metal ions, organic matter, and other harmful substances in the wastewater, making it easy to filter and remove; The second part is an electrolyte filter, which filters and removes the polymer in the sensitive word section; The third part is a high-speed ultraviolet irradiation device, which oxidizes organic compounds and chemical complexing agents in water by ultraviolet rays, reducing CODcr and BOD5.
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