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 1970’s 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