Editing Smelting (section)

===Wastewater===
Wastewater pollutants discharged by iron and steel mills includes gasification products such as [[benzene]], [[naphthalene]], [[anthracene]], [[cyanide]], [[ammonia]], [[phenol]]s and [[cresol]]s, together with a range of more complex [[organic compound]]s known collectively as [[polycyclic aromatic hydrocarbon]]s (PAH).<ref name="EPA ironsteel">{{cite report |date=2002 |title=Development Document for Final Effluent Limitations Guidelines and Standards for the Iron and Steel Manufacturing Point Source Category |chapter=7. Wastewater Characterization |chapter-url=http://www.epa.gov/eg/iron-and-steel-manufacturing-effluent-guidelines-documents |publisher=EPA |pages=7–1ff |id=EPA 821-R-02-004}}</ref> Treatment technologies include recycling of wastewater; [[settling basin]]s, [[clarifier]]s and filtration systems for solids removal; [[oil skimmer]]s and filtration; [[chemical precipitation]] and filtration for dissolved metals; [[Adsorption#Activated carbon|carbon adsorption]] and biological oxidation for organic pollutants; and evaporation.<ref>{{cite report |title=Development Document for Effluent Limitations Guidelines, New Source Performance Standards and Pretreatment Standards for the Iron and Steel Manufacturing Point Source Category; Vol. I |url=https://www.epa.gov/eg/iron-and-steel-manufacturing-effluent-guidelines-documents |date=May 1982 |publisher=EPA |pages=177–216 |id=EPA 440/1-82/024a}}</ref>

Pollutants generated by other types of smelters varies with the base metal ore. For example, aluminum smelters typically generate [[fluoride]], [[benzo(a)pyrene]], antimony and nickel, as well as aluminum. Copper smelters typically discharge cadmium, lead, [[zinc]], arsenic and nickel, in addition to copper.<ref>EPA (1984). "Nonferrous Metals Manufacturing Point Source Category." ''Code of Federal Regulations,'' {{USCFR|40|421}}.</ref> Lead smelters may discharge [[antimony]], asbestos, cadmium, copper and zinc, in addition to lead.<ref>{{cite report |title=Development Document for Effluent Limitations Guidelines and Standards for the Nonferrous Metals Manufacturing Point Source Category; Volume IV |url=https://www.epa.gov/eg/nonferrous-metals-manufacturing-effluent-guidelines-documents-1990-amendment |date=May 1989 |publisher=EPA |pages=1711–1739 |id=EPA 440/1-89/019.4}}</ref>