The present invention provides a method and apparatus for purifying effluent wastewater utilizing electrophoretic cross-flow filtration and electrode ionization. The method first comprises filtering the water in a cross-flow direction with a filter membrane in the presence of an electric field that is operative to drive suspended particles away from a surface of the filter membrane. The permeate containing dissolved solids is next passed through a mixture of at least one cation-exchange resin and at least one anion-exchange resin disposed between a cation-selective membrane and an anion-selective membrane in the presence of an electric field. The electric field drives cations in the permeate through the cation-selective membrane, and drives anions in the permeate through the anion-selective membrane, thereby to form deionized water. The apparatus includes cell modules adapted to be used in plate-and-frame or radial flow configurations.