An apparatus and a method for electrochemical modification of liquid streams employing an electrolytic cell which utilizes an oxidation site defined by an anode, an anode compartment comprising liquid electrolyte anolyte where oxidation is effected, a cathode compartment comprising liquid electrolyte catholyte where reduction is effected, a cathode comprising conducting cathode particulates forming a cathode particulates bed and a current feeder device in at least intermittent contact with said cathode particulates where the cathode particulates are in motion and the particulates motion is substantially independent of bulk electrolyte flow, a separator which confines the cathode particulates to the cathode compartment, constrains electrolyte flow through the cathode particulates bed and permits ionic conduction of current between the anode and cathode, a cathode particulates conveyance system that manipulates cathode particulates motion. A separate system circulates the liquid undergoing modification through the electrolytic cell. An unidirectional current driving system drives unidirectional electric current supported by the liquid streams from the anode through the anolyte and the separator and into the catholyte and to the cathode particulates and to the current feeder device during the contact between the cathode particulates and the current feeder device.