Electrodialysis Reversal (EDR) is an electrochemical separation process that allows selective passage of ions, or charged species, in solutions. Only anions, or negatively charged ions, can pass through an anion exchange membrane while cation exchange membranes transport positively charged ions or cations. Ions are transferred through ion exchange membranes by means of direct current (DC) voltage and are removed from the feed water as the current drives the ions through the membranes to desalinate the process stream. EDR systems reduce the fouling tendencies of the water by reversing the polarity of the electrodes every 15 to 20 minutes. This change in polarity causes the scale to disassociate from the membranes. Membranes can operate on waters with up to 0.5 ppm chlorine, making systems tolerant to disinfection.
Applications for EDR technology include municipal drinking water, industrial process water, and wastewater reuse projects. Municipalities find EDR successful for the removal of radium, arsenic, and perchlorates as well as desalination of well and surface waters. Electrodialysis reversal reliably desalinates water to customer specifications for industrial process requirements, such as boiler make up water. Additionally, because of its rugged membranes and high chlorine tolerance, EDR membranes are ideal for wastewater reuse projects.
EDR System Parameters:
The EDR product line has a wide flow capacity with the ability to treat anywhere from 500 GPD up to 1.6 MGD. Electrodialysis reversal systems are able to reduce dissolved ions in process streams of up to 12,000 ppm total dissolved solids (TDS) from 50% up to 94% removal. By using multiple stages (stacks in series), systems are designed to handle a wide range of treatment needs.

With our experience and expertise, we can provide a standard EDR system and replacement parts or engineer a complete system tailored to your needs.