Desalination is a separation process used to reduce the dissolved salt content in Sea Water to a usable level.
The purification processes involve three liquid streams:
The saline feed water is drawn from open sea or underground beach well sources. It is separated by the desalination process into the two output streams: the low-salinity product water and very saline concentrate streams. The use of desalination overcomes the paradox faced by mankind, that of having access to a practically inexhaustible supply of saline water but having no way to use it. In the past, the difficulty and expense of removing various dissolved salts from water made saline waters an impractical source of potable water. However, starting in the 1950s, desalination began to appear to be economically practical for ordinary use, under certain circumstances.
The product water of the desalination process is generally water with less than 500 mg/1 dissolved solids, which is suitable for most domestic, industrial, and agricultural uses.
A by-product of desalination is brine. Brine is a concentrated salt solution (with more than 40,000 mg/1 dissolved solids) that must be disposed of, generally by discharge into deep saline aquifers or surface waters with a higher salt content. Brine can also be diluted with treated effluent and disposed of by spraying on golf courses and/or other open space areas.