Electrodialysis Reversal (EDR)
High-Recovery Brackish Water Desalination.
Gradiant’s Electrodialysis Reversal (EDR) systems use an electric current to migrate dissolved salt ions through a membrane stack. The units contain alternating layers of cationic and anionic ion exchange membranes. The direction of ion flow is periodically reversed by changing the polarity of the applied electric current. Different ion exchange membrane configurations and types may be used to selectively concentrate or extract specific target ions, allowing the product water salinity to be tuned to a target TDS concentration.
EDR can provide compelling cost advantages in some situations. Unlike RO, which relies on pressurized water, EDR uses voltage differences to drive ions. This results in greater tolerance to inorganic scaling and biological fouling and reduces pre-treatment and chemical needs. The decision to use EDR, RO, or other technologies depends on case-specific conditions, such as feed and product water TDS and if selective ion removal is required. Typical applications in brine concentration, brackish water desalination of groundwater, and ultrapure water production.
Key Benefits of Gradiant's EDR Technology:
Robust System Reliability
Treatment of water with high inorganic scale (such as silica) or biological contamination. Higher turbidity allowance.
Selective Ion Removal
Selective concentration and extraction of ions based on ion exchange membrane configurations.
Lower CAPEX and OPEX
Cost advantages in case-specific conditions depending on water chemistry and process needs. Reduced pre-treatment and chemical needs, and brine disposal costs.