EDR (Electro Dialysis Reversal)
EDR (Electrodialysis Reversal) is an electrolytic process that removes ionic species from a brackish water or wastewater source. Ionic species or dissolved solids in water migrate through ion exchange membranes under the influence of electrical current, to produce water that meets drinking water standards, or wastewater that can be reused for such things as irrigation. EDR is best applied where high rates of water recovery are desired.
Environmental Benefit
GE’s EDR technology produces potable water from undrinkable brackish water sources in areas where water is scarce. In a facility in Barcelona, Spain, GE’s EDR technology is designed to provide over 50 million gallons of potable water per day, equivalent to the daily water consumption of over 260,000 Spanish households for a variety of uses.
Operating Benefit
GE’s EDR technology requires fewer anti-scalant chemicals than Reverse Osmosis (RO), in many cases using none at all. Compared to a typical RO treatment facility producing 3.8 million gallons of water per day, GE’s EDR technology, operating at 83% efficiency, is designed to eliminate the need for over 28,000 pounds of anti-scalant, reducing operating costs by more than $100,000 per year at typical 2008 chemical prices.
The environmental challenge
Access to a clean and reliable water source is a necessity for all communities, but for some, fresh water is a scarce resource. GE recognizes this and has developed technology that can create high-quality, clean water with low water waste volume.
GE’s innovative solution
Electrodialysis Reversal (EDR)™ is an efficient water desalination technology that maximizes fresh water creation from scarce water resources, while minimizing the amount of byproduct that requires disposal.
GE’s EDR technology produces potable water from undrinkable, brackish sources by removing the ionic species to create water for drinking, industrial and agricultural use. EDR uses a small quantity of electrical current to move the ionic species, which are then segregated by ion exchange membranes and removed from the water.
The removed ionic species are concentrated in a small volume to maximize the desalination conversion rate. This high-efficiency operation means the amount of water withdrawn from the water source is reduced and the wastewater disposal volume is low, resulting in a more efficient use of the water source and a cost reduction of final discharge treatment systems.
Environmental impact
GE’s EDR technology reduces the dissolved solids of the brackish and wastewater while operating at high water efficiency. For a growing community in the United States, an EDR pilot plant proved that GE’s EDR technology could achieve desired water purity quality and also operate at 94 percent water recovery, a high level of efficiency for desalination technology. A full scale EDR plant was constructed and its success has lead to capacity expansions three times since EDR technology was first installed in 1990. The capacity of this EDR plant is currently 13.6 million gallons per day of drinking water.
Most EDR systems continuously operate at 85 to 94 percent efficiency, depending on feed water quality. GE’s EDR technology requires fewer acid or anti-scalant chemicals than reverse osmosis, and in many cases requires close to none.
Also, unlike polyamide reverse osmosis technology, GE’s EDR technology can treat water with a free chlorine residual, making EDR an ideal desalination technology to treat many municipal drinking and reclaimed wastewaters where chlorine is used as a disinfectant.
Reducing costs
GE’s EDR technology uses a polarity reversal feature to automatically clean the membrane surface. This contributes to both the high water recovery rate of up to 94 percent and long membrane life.
