Desalination is the process of removing dissolved salts from a liquid.
Another way to describe desalination is the production of freshwater from salty water by introducing energy either to pump the feed water through a semi permeable membrane or as a heat source for an evaporation process.
Desalination is a well established technology that reliably produces process water, ultrapure, potable water or recovers valuable products for manufacturing industry.
The different water qualities can be produced by a large selection of systems including membrane or thermal technologies designed to treat industrial or municipal wastewater, seawater, brackish groundwater, surface water or potable water. The alternative solutions include:
The development of the technologies over the last ten years has reduced capital, operating costs and especially the energy consumed.
However the careful selection of the most appropriate solution depends on the source of the feed and the treated water quality required so that the costs and environmental impact of the solution can be minimized.
Membrane solution - substantial reduction in energy consumed by the high pressure pumps through advances in pre-treatment technology to protect the membranes, higher efficiency membrane development, high efficiency process designs and energy recovery systems while still maintaining the high quality of treated water.
Thermal solutions - increased use of low temperature high efficiency vacuum systems that can be operated on waste heat with a low electrical energy demand.
The applications range from 10 m3/day to 300,000 m3/day and Veolia Water and Veolia Water Systems have the experience of building or operating approximately 800 desalination project. These projects treat approximately 3 million cubic meters a day and are almost equally divided between membrane and thermal solutions.