Desalination or desalinization refers to any of several processes that remove the excess salt and other minerals from water in order to obtain fresh water suitable for animal consumption or irrigation, and if almost all of the salt is removed, for human consumption, sometimes producing table salt as a by-product.
The traditional process used in these operations is distillation - essentially the boiling of water at less than atmospheric pressure, and thus a much lower temperature than normal.
Due to the reduced temperature, energy is saved.
In the last decade, membrane processes have grown very fast, and Reverse Osmosis (R.O.) has taken nearly half the world's installed capacity.
Membrane processes use semi-permeable membranes to filter out dissolved material or fine solids.
The systems are usually driven by high-pressure pumps, but the growth of more efficient energy-recovery devices has reduced the power consumption of these plants and made them much more viable; however, they remain energy intensive and, as energy costs rise, so will the cost of R.O. water.