Experimental Techniques and Other Developments
Many desalination techniques have been researched, with varying degrees of success.
One such process was commercialised by Modern Water PLC using forward osmosis, with a number of plants reported to be in operation.
The US government is working to develop practical solar desalination.
The Passarell process uses reduced atmospheric pressure rather than heat to drive evaporative desalination. The pure water vapor generated by distillation is then compressed and condensed using an advanced compressor. The compression process improves distillation efficiency by creating the reduced pressure in the evaporation chamber. The compressor centrifuges the pure water vapor after it is drawn through a demister (removing residual impurities) causing it to compress against tubes in the collection chamber. The compression of the vapor causes its temperature to increase. The heat generated is transferred to the input water falling in the tubes, causing the water in the tubes to vaporize. Water vapor condenses on the outside of the tubes as product water. By combining several physical processes, Passarell enables most of the system's energy to be recycled through its subprocesses, namely evaporation, demisting, vapor compression, condensation, and water movement within the system.
Geothermal energy can drive desalination. In most locations, geothermal desalination beats using scarce groundwater or surface water, environmentally and economically.
Nanotube membranes may prove to be effective for water filtration and desalination processes that would require substantially less energy than reverse osmosis.
Biomimetic membranes are another approach.
On June 23, 2008, Siemens Water Technologies announced technology based on applying electric fields that purports to desalinate one cubic meter of water while using only 1.5 kWh of energy. If accurate, this process would consume only one-half the energy of other processes. Currently, Oasis Water, which developed the technology, still uses three times that much energy.
Freeze-thaw desalination uses freezing to remove fresh water from frozen seawater.
In 2009, Lux Research estimated the worldwide desalinated water supply will triple between 2008 and 2020.
Read more about this topic: Desalination
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