Editing Solvay process (section)

== Byproducts and wastes ==
The principal byproduct of the Solvay process is [[calcium chloride]] (CaCl<sub>2</sub>) in aqueous solution. The process has other waste and byproducts as well.<ref name="ESAPA" /> Not all of the limestone that is calcined is converted to quicklime and carbon dioxide (in reaction II); the residual calcium carbonate and other components of the limestone become wastes. In addition, the salt brine used by the process is usually purified to remove magnesium and calcium ions, typically to form carbonates ([[Magnesium bicarbonate|MgCO<sub>3</sub>]], [[Calcium carbonate|CaCO<sub>3</sub>]]); otherwise, these impurities would lead to scale in the various reaction vessels and towers. These carbonates are additional waste products.

In inland plants, such as that in [[Solvay, New York]], the byproducts have been deposited in "waste beds"; the weight of material deposited in these waste beds exceeded that of the soda ash produced by about 50%. These waste beds have led to water pollution, principally by calcium and chloride. The waste beds in Solvay, New York substantially increased the salinity in nearby [[Onondaga Lake]], which used to be among the most polluted lakes in the U.S.<ref>[http://www.onlakepartners.org/p12036.html Onondaga Lake Partnership]. Retrieved 2006-10-14.</ref> and is a [[superfund]] pollution site.<ref>U.S. Environmental Protection Agency, superfund [http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0203382 ID NYD986913580] {{Webarchive|url=https://web.archive.org/web/20110517155025/http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0203382 |date=2011-05-17 }}. Retrieved 2006-10-14.</ref> As such waste beds age, they do begin to support plant communities which have been the subject of several scientific studies.<ref>{{cite journal | last1 = Cohn | first1 = E.V.J. | last2 = Rostanski | first2 = A. | last3 = Tokarska-Guzik | first3 = B. | last4 = Trueman | first4 = I.C. | last5 = Wozniak | first5 = G. | year = 2001 | title = The flora and vegetation of an old Solvay process tip in Jaworzno (Upper Silesia, Poland) | journal = Acta Soc. Bot. Pol. | volume = 70 | issue = 1| pages = 47–60 | doi=10.5586/asbp.2001.008| doi-access = free | hdl = 20.500.12128/13191 | hdl-access = free }}</ref><ref>[[Ed Michalenko|Michalenko, Edward M.]] (1991). "Pedogenesis and invertebrate microcommunity succession in immature soils originating from chlor-alkali wastes," doctoral dissertation, [[State University of New York College of Environmental Science and Forestry]].</ref>

At seaside locations, such as those at [[Saurashtra (region)|Saurashtra]], Gujarat, India,<ref>[https://web.archive.org/web/20080407001754/http://dsir.nic.in/reports/techreps/tsr148.pdf "Technology in the Indian Soda Ash Industry"], Technology Status Report #148 (October, 1995), [http://dsir.nic.in Department of Scientific and Industrial Research], Ministry of Science & Technology, India. Archived by WebCite from [http://dsir.nic.in/reports/techreps/tsr148.pdf  this original URL] on 2008-03-01.</ref> the CaCl<sub>2</sub> solution may be discharged directly into the sea, apparently without substantial environmental harm (although small amounts of heavy metals in it may be a problem), the major concern is discharge location falls within the Marine National Park of Gulf of Kutch which serves as habitat for coral reefs, seagrass and seaweed community. At [[Osborne, South Australia]],<ref>[https://archive.today/20120910072845/http://www.penrice.com.au/company.htm ''Penrice Soda Holdings Limited'']. Retrieved 2006-10-14.</ref> a settling pond is now used to remove 99% of the CaCl<sub>2</sub> as the former discharge was silting up the shipping channel. At [[Rosignano Solvay]] in Tuscany, Italy the limestone waste produced by the Solvay factory has changed the landscape, producing the "Spiagge Bianche" ("White Beaches"). A report published in 1999 by the United Nations Environment Programme (UNEP), listed Spiagge Bianche among the priority pollution hot spots in the coastal areas of the Mediterranean Sea.<ref>{{cite journal |last1=UNEP. Coordinating Unit for the Mediterranean Action Plan Coordinated Mediterranean Pollution Monitoring and Research Programme, WHO |title=Identification of priority pollution hot spots and sensitive areas in the Mediterranean |journal=MAP Technical Reports Series |date=1999 |issue=124 |url=http://wedocs.unep.org/bitstream/handle/20.500.11822/535/mts124eng.pdf?sequence=5&isAllowed=y |accessdate=11 September 2020}}</ref>