Electroplating effluent

Malekzadeh, F., Farazmand, A., Ghafourian, H. et al. (2002). Uranium accumulation by a bacterium isolated from electroplating effluent. World J. Micobiol. Biotechnol. 18,295-300. 

Feng, X., Wu, Z. Chen, X. (2007) Removal of metal ions from electroplating effluent by EDI process and recycle of purified water. Separation and Purification Technology, 57, 257-263. 

Due to their high efficiency, ELMs would appear to be attractive alternatives to SLMs. However ELM systems often suffer from problems of low solubility and difficulties with de-emulsification. To overcome these problems, a new liquid membrane process, the emulsion free liquid membrane (EI M), was developed by Kumar ef al. (60). Application of this novel technique to hydrometallurgical processes is quite promising (67). Recent studies of separating heavy metals, such as Cr(VI) and Cu(II) from electroplating effluents, with an EFLM system indicate that the technique is very efficient and superior to other types of LMs. 

The depressed prices of most metals in world markets in the 1980s and early 1990s have slowed the development of new metal extraction processes, although the search for improved extractants continues. There is a growing interest in the use of extraction for recovery of metals from effluent streams, for example the wastes from pickling plants and electroplating (qv) plants (276). Recovery of metals from Hquid effluent has been reviewed (277), and an AM-MAR concept for metal waste recovery has recentiy been reported (278). Possible appHcations exist in this area for Hquid membrane extraction (88) as weU as conventional extraction. Other schemes proposed for effluent treatment are a wetted fiber extraction process (279) and the use of two-phase aqueous extraction (280). 

Industrial Wastewater Treatment. Industrial wastewaters require different treatments depending on their sources. Plating waste contains toxic metals that are precipitated and insolubiHzed with lime (see Electroplating). Iron and other heavy metals are also precipitated from waste-pidde Hquor, which requires acid neutralization. Akin to pickle Hquor is the concentrated sulfuric acid waste, high in iron, that accumulates in smokeless powder ordinance and chemical plants. Lime is also useful in clarifying wastes from textile dyeworks and paper pulp mills and a wide variety of other wastes. Effluents from active and abandoned coal mines also have a high sulfuric acid and iron oxide content because of the presence of pyrite in coal. 

Electroplating is done both in job shops, where a customer s work is plated, and in captive (in-house) shops. There were reported to be about 7500 plating plants in the United States (4) in 1992. This is a decrease from the ca 12,000 reported by the same source in 1980. The reduction, particularly in the number of smaller job shops, is related to the problems in meeting the waste regulations imposed on plating shop effluents. 

The same process will hold good for treating effluents from an eleciroplaiing shop should it alsocxi.sl with a paint shop. The effluents from an electroplating shop are strong wastes and need special consideration, as noted in the subsequent text and considered in Figure A 13.12. 

EPA. 1986a. Effluent guidelines and standards. Electroplating point source category. U.S. Environmental Protection Agency. Code of Federal Regulations. 40 CFR 413.02. 

Electrochemistry is widely used in industry, for example in effluent treatment, corrosion prevention and electroplating as well as in electrochemical synthesis. Electrochemical synthesis is a well-established technology for major processes such as aluminium and chlorine production there is, however, increased interest in the use of electrochemistry for clean synthesis of fine chemicals. The possible green benefits of using electrochemical synthesis include ... 

Effluent Guidelines and Standards Electroplating - Definitions of Total Toxic Organics >0.01 mg/L 40 CFR 413.02 EPA 1981... 

Remediation options for the treatment of electroplating and leather tanning effluent containing chromium -A review. Miner. Proc. Extractive Metall. Rev., 2, 99-130. 

Cadmium is found in low concentrations in most soils and waters. It is produced as a by-product of zinc and lead mining and smeltering. Industrial use of cadmium has led to a dramatic increase in environmental problems caused by this element. Cadmium is used in semiconductors, nickel-cadmium batteries, electroplating, polyvinyl chloride (PVC) manufacturing, and control rods for nuclear reactors. The most important sources for aquatic contamination are active and inactive lead-zinc mines, land application of sewage sludge, zinc-cadmium smelters, effluents from plastic and steel production, and wastewaters from the production of nickel-cadmium batteries and electroplating (Zuiderveen, 1994). 

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