An electrodialysis apparatus includes a stack of alternating cation and anion semi-permeable, ion-selective membranes disposed between a positive DC potential anode electrode and a negative DC potential cathode electrode. The cation and anion selective membranes can be selective for monovalent or multivalent ions and form compartments therebetween through alternate compartments of which flow concentrate and diluate solutions such that the concentrate and diluate solutions are separated from each other by the ion selective membranes. Due to the potential maintained across each of the compartments and the cation and anion selective membranes separating the compartments, cations and anions as well as water will migrate from the diluate solution to the concentrate solution. An anode electrode rinse solution is circulated through an outer most compartment adjacent to the anode electrode and a separate cathode electrode rinse solution is circulated through an outer most compartment adjacent to the cathode electrode.