Editing Brine (section)

==Wastewater==
{{main|Industrial wastewater treatment#Brine treatment}}
Brine is a byproduct of many industrial processes, such as [[desalination]], power plant [[cooling tower]]s, [[produced water]] from oil and [[natural gas]] extraction, [[Acid mine drainage|acid mine or acid rock drainage]], [[reverse osmosis]] reject, [[Chloralkali process|chlor-alkali]] wastewater treatment, pulp and paper mill effluent, and waste streams from food and beverage processing. Along with diluted salts, it can contain residues of pretreatment and cleaning chemicals, their reaction byproducts and heavy metals due to corrosion.

Wastewater brine can pose a significant environmental hazard, both due to corrosive and sediment-forming effects of salts and toxicity of other chemicals diluted in it.<ref name=Desalitech>{{cite web |url=http://desalitech.com/7-ways-to-dispose-of-brine-waste/ |title=7 Ways to Dispose of Brine Waste |publisher=Desalitech |access-date=18 July 2017 |archive-date=27 September 2017 |archive-url=https://web.archive.org/web/20170927155806/http://desalitech.com/7-ways-to-dispose-of-brine-waste/ |url-status=dead }}</ref>

Unpolluted brine from desalination plants and cooling towers can be returned to the ocean. From the desalination process, reject brine is produced, which proposes potential damages to the marine life and habitats.<ref>5.	A. Giwa, V. Dufour, F. Al Marzooqi, M. Al Kaabi, S.W. Hasan, "Brine management methods: Recent innovations and current status", ''Desalination'', Volume 407, 2017, pp. 1–23</ref> To limit the environmental impact, it can be diluted with another stream of water, such as the outfall of a [[Sewage treatment|wastewater treatment]] or power plant. Since brine is heavier than seawater and would accumulate on the ocean bottom, it requires methods to ensure proper diffusion, such as installing underwater [[diffuser (sewage)|diffusers]] in the [[sewerage]].<ref>{{cite web|url=http://www.lenntech.com/processes/desalination/brine/general/brine-disposal.htm |title=Reverse Osmosis Desalination: Brine disposal |publisher=Lenntech |access-date=18 July 2017}}</ref> Other methods include drying in [[evaporation pond]]s, injecting to deep wells, and storing and reusing the brine for irrigation, de-icing or dust control purposes.<ref name=Desalitech/>

Technologies for treatment of polluted brine include: membrane filtration processes, such as [[reverse osmosis]] and [[forward osmosis]]; ion exchange processes such as [[electrodialysis]] or [[Ion-exchange resin|weak acid cation exchange]]; or evaporation processes, such as thermal brine concentrators and [[Crystallization#Evaporative crystallizers|crystallizers]] employing [[mechanical vapour recompression]] and steam.  New methods for membrane brine concentration, employing osmotically assisted reverse osmosis and related processes, are beginning to gain ground as part of zero liquid discharge systems (ZLD).<ref>{{cite web |title=Novel Technology for Concentration of Brine Using Membrane-Based System |url=https://www.osmotic-engineering.com/wp-content/uploads/2019/08/WT_AMBCArticle.pdf |publisher=Water Today |access-date=31 August 2019}}</ref>