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Types of Desalination

Thermal
Multi-stage Flash
Multi-effect Distillation
Vapor Compression Distillation

Membrane
Reverse Osmosis
Electrodialysis
Electrodialysis Reversal

Middle East Desalination

Huntington Beach Proposal

Sources Cited

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Electrodialysis Reversal Process

Operates on the same general principles as electrodialysis unit, except that it provides a continuous self cleaning system.
It uses periodic reversal of the DC polarity to allow systems to run at higher recovery raters.

History of use
In the early 1970s it was introduced, with applications in municipal drinking water, industrial process water, and waste water reuse projects.

Mechanism
At intervals of several times an hour, the polarity of the electrode is reversed.
Simultaneously the flows are switched so that the brine channels become the fresh water.
The reversal process is useful in breaking up and flushing out scales, slimes, and other deposits.
Benefits
Allows unit to operate with fewer pretreatment chemicals
Chlorine resistant membranes tolerant to disinfection
High recovery system
o The system is able to reduce dissolved ions of up to 12,000ppm of total dissolved solids, with 94% removal
Land-based applications
Long membrane life, between 5 and 10 years
Less sensitive than reverse osmosis to particulates and metal oxides

Limits to system parameters are it has the ability to treat anywhere from 500 Gallons/day up to 1.6 gallons/day.
 

Sources


http://www.ionics.com/technologies/edr/


http://www.iwra.siu.edu/win/win2000/win03-00/semiat.pdf


http://www.twdb.state.tx.us/Desalination/The%20Future%20of%20Desalination%20in%20Texas%

20-%20Volume%202/documents/C1.pdf