Electrodialysis Reversal (EDR)
Systems for deionization, desalination, and demineralization
Electrically-driven separation technology, such as electrodeionization (EDI), electrodialysis (ED), and electrodialysis reversal (EDR) use applied electrical potential to separate soluble ions and salts from a water or process stream. The separation occurs through a semi-permeable material, called an ion exchange membrane. In electrically-driven separation technologies, ions are transferred through the membrane. This is opposite of pressure-driven separation technologies for which water is transferred through the membrane. There are two types of ion exchange membranes used in what is commonly referred to as a cell, which is a pairing of anionic and cationic membranes. Anions are transferred through anionic membranes and travel toward to anode, while cations are transferred through cationic membranes and travel toward the cathode. Many cells are combined to form a stack, which can then be used in systems of all sizes.