PCB--the most polluted area

The so-called "PCB" is the abbreviation of "Printed Circuit Board" in English. It means the meaning of printed circuit boards. In the production process, there are electroplating and other processes, so it involves the disposal of waste liquids and discarded circuit boards. The main ones are the heavy metals. Pollution problems.

Heavy metal refers to a metal with a specific gravity greater than 4 or 5, a total of 45 species. The heavy metals mentioned in the sense of environmental pollution include, in addition to significant bio-toxic mercury, cadmium, lead, chromium, zinc, copper, cobalt, nickel, and tin with certain toxicities, arsenic, which contains highly toxic metals. Among them, although manganese, copper, zinc, etc. are necessary trace elements for the human body, exceeding a certain concentration will also cause harm to the human body. The use of water contaminated with heavy metals for irrigation and aquaculture can cause serious harm. Heavy metals pass through the biomagnification of the food chain and are accumulated in millions of times in higher organisms. They eventually enter the human body and accumulate in certain organs causing chronic poisoning and endangering human health. Because heavy metal pollution usually occurs in the human body after it accumulates for up to 10 years, this type of hazard will not receive the attention it deserves in the beginning. However, most of the lesions caused by heavy metal pollution are irreversible, and once the disease is difficult to treat, they often have a devastating impact on the health of individuals. The most typical case is the case of mink disease in Japan, which was caused by a Japanese fertilizer plant discharging mercury-containing sewage into rivers near the town of Mizuho, ​​causing a tragedy.

Most of the heavy metal pollution in China is caused by man-made pollution. The main sources of pollution are metal smelter wastewater, electroplating industrial wastewater, chemical pollution, landfills and metal processing, and recycling of used electrical appliances. However, compared with its serious consequences, most of the heavy metal forms appear to be "low-key." Since heavy metals exist in the water as inorganic ions, they are colorless and odorless and require highly accurate instruments to detect them. In China, laboratories at the county level usually do not have testing conditions.

For PCBs, the types of pollutants are relatively concentrated, mainly COD and heavy metal copper pollution, no cyanogen / cadmium / chromium and other highly toxic emissions, there is no carcinogenic, teratogenic, genetic mutation caused by the three substances discharge. Among them, copper ions, which are the major contaminants of heavy metals, are relatively easy to remove by the treatment of copper ions. However, a small number of PCB companies do not understand the importance of environmental protection and clean production. Many companies waste water treatment, waste water reuse, clean production, etc. are to meet the inspection, or for the corresponding qualification certificate, did not raise it to the corporate social responsibility and legal height, there are many bad manufacturers for the waste bath The treatment is simply to extract valuable precious metals and secretly discharge the remaining waste liquids that are useless to them into the river without treatment, causing great pollution, and also causing the PCB production to cause relatively large environmental pollution. impression.

For the solution to the status quo, Xiao Bian thinks that it mainly starts from the following aspects. First, the PCB industry must strengthen industry standards and strengthen self-discipline. Industry associations should supervise the handling of standards and efforts, and relevant government departments must Enterprises do regular and irregular monitoring work. Then it is necessary to start with the technical aspects to solve the pollution problem. The direction of environmental protection in the future should be energy conservation, emission reduction, consumption reduction, resource regeneration, and highly efficient environmental protection technologies, and more and more physical and biological treatment methods should be used in place of traditional chemical treatment technologies.