Desalination

Abstract Desalination is the production of fresh potable water from a saline water source (seawater or brackish water) via membrane separation or evaporation. Desalination plants operate in more than 120 countries worldwide, and some desert states, such as Saudi Arabia and the United Arab Emirates, rely on desalinated water for more than 70% of their water supply. Sea or brackish waters are typically desalinated using two general types of water treatment technologies—thermal evaporation (distillation) and membrane separation. All thermal desalination technologies use distillation (heating of source water) to produce water vapor that is then condensed into low‐salinity potable water. The thermal desalination technologies most widely used today are multistage flash distillation (MSF), multiple effect distillation (MED), and vapor compression (VC). Membrane desalination is a process of separating minerals from source water using semipermeable membranes. Two general types of technologies are currently used in membrane desalination—reverse osmosis (RO) and electrodialysis (ED). Reverse osmosis desalination is the most widely used membrane separation process today. Currently, there are more than 2000 RO membrane seawater desalination plants worldwide whose total production capacity is in excess of 3 million cubic meters per day (800 MGD).