Reversible electrodialysis

Reverse Electrodialysis (EDR) is a process that involves the transport of ions through alternating cation- and anion-selective membranes using electrical energy. Electrodes are placed at both ends of each EDR module, inducing the flow of cations and anions through the individual membranes. The special design of ion-selective membranes allows for the flow of two streams – the desalted (dilute) and the concentrated (concentrate) streams. In EDR modules, the polarity of the electrodes is periodically reversed, which helps reduce the risk of fouling and scaling.

Reverse electrodialysis can be used as a membrane-based demineralization method when there are high requirements for the amount of concentrate, as well as when high concentrations of salts are desired in the concentrate for recovery purposes. EDR is particularly useful when there is a high concentration of silica in the water being treated. This system is suitable for a wide range of water pH, from 1 to 14.