Desalination, desalinization, or desalinisation refers to any of several processes that remove some amount of salt and other minerals from water. More generally, desalination may also refer to the removal of salts and minerals, as in soil desalination.
Water is desalinated in order to convert salt water to fresh water so it is suitable for human consumption or irrigation. Sometimes the process produces table salt as a by-product. Desalination is used on many seagoing ships and submarines. Most of the modern interest in desalination is focused on developing cost-effective ways of providing fresh water for human use in regions where the availability of fresh water is, or is becoming, limited.
Large-scale desalination typically uses extremely large amounts of energy as well as specialized, expensive infrastructure, making it very costly compared to the use of fresh water from rivers or groundwater.
However, along with recycled water this is one of the few non-rainfall dependent water sources particularly relevant to countries like Australia which traditionally have relied on rainfall in dams to provide their drinking water supplies.
The world's largest desalination plant is the Jebel Ali Desalination Plant (Phase 2) in the United Arab Emirates. It is a dual-purpose facility that uses multi-stage flash distillation and is capable of producing 300 million cubic metres of water per year. By comparison the largest desalination plant in the United States is located in Tampa Bay, Florida, and operated by Tampa Bay Water, which began desalinating 34.7 million cubic meters of water per year in December 2007. The Tampa Bay plant runs at around 12% the output of the Jebel Ali Desalination Plants. The largest desalination plant in South Asia is the Minjur Desalination Plant near Chennai in India which produces 100,000 cubic meters of water per day, or 36.5 million cubic meters of water per year. According to International Desalination Association 2009, there are 14,451 desalination plants in operation worldwide, producing 59.9 million cubic meters per day (15.8 billion gallons a day), a year on year increase of 12.3%.