Reverse osmosis desalination
The leading process for desalination in terms of installed capacity and yearly growth is reverse osmosis (RO) (Fritzmann and others, 2007). The RO membrane processes use semipermeable membranes and applied pressure (on the membrane feed side) to preferentially induce water permeation through the membrane while rejecting salts. Reverse osmosis plant membrane systems typically use less energy than thermal desalination processes (Warsinger and others, 2015). Desalination processes are driven by either thermal (e.g., distillation) or electrical (e.g., RO) as the primary energy types. Energy cost in desalination processes varies considerably depending on water salinity, plant size and process type. At present the cost of seawater desalination, for example, is higher than traditional water sources, but it is expected that costs will continue to decrease with technology improvements.
Warsinger, David M.; Mistry, Karan H.; Nayar, Kishor G.; Chung, Hyung Won; Lienhard V, John H, 2015, Entropy Generation of Desalination Powered by Variable Temperature Waste Heat: Entropy. pp. 7530–7566. Bibcode:2015Entrp..17.7530W. doi:10.3390/e17117530.