Desalination
Desalination refers to any of several processes that removes the excess salt and minerals from sea water in order to obtain potable fresh water, sometimes producing table salt as a byproduct.
Desalination has long been used on ships, submarines and islands, where cost is no object.
Desalination of brackish water is already commonplace in the U.S., where it is used to meet treaty obligations for river water entering Mexico.
Desalination of ocean water is common in the Middle East, where a number of countries use oil-fired stills to provide city drinking water.
The price of desalination is rapidly declining. A modern, large, efficient plant is within 20% of the cost of developing a new, local source of fresh water. Desalination stills now control pressure, temperature and brine concentrations to optimize the water extraction efficiency. Other methods of desalination include reverse osmosis and pressure barrier osmosis. Nuclear-powered desalination could be very economical on a large scale.