Electrodialysis is a process of electrochemical separation in which ions are transferred through ion exchange membranes by means of a continuous current.
In this case, the membranes have ionic groups attached to them in such a way that allows the passage of ions of the opposite charge to their own, and always from the less concentrated solution to the more concentrated one, which can cause significant salt concentrations to form around the membranes, resulting in precipitations and even scaling.
To avoid these problems, reversible electrodialysis(EDR) was developed, which involves periodically changing the polarity of the electrodes (three or four times every hour). This reversion functions as a self-cleaning system for the membranes.
Depending on the type and configuration of the membranes, different water treatment results are achieved.