Abstract: Apparatus and method for electrochemically removing ions and other contaminants from an aqueous liquid by passing the liquid to be treated into the base of a vertically disposed treatment zone, said zone being formed by a vertically disposed cylindrical electrode and at least one internal electrode which is axially disposed within said cylindrical electrode. The electrodes are connected to a source of direct current and have contained between them, in the treatment zone, a solid particulate bed forming a medium of low electrical conductivity through which the current passes while the liquid to be treated is passed into the base of the treatment zone with sufficient pressure to transport it upward through the treatment zone. The liquid, free of the ions or other contaminants sought to be removed, is then removed from the top of the treatment zone.