Desalination, desalinization, or desalinisation refers to any of several processes that remove excess 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 be converted to fresh water suitable for human consumption or irrigation. Sometimes the process produces table salt as a by-product. It 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 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. The large energy reserves of many Middle Eastern countries, along with their relative water scarcity, have led to extensive construction of desalination in this region. By mid-2007, Middle Eastern desalination accounted for close to 75% of total world capacity.