An apparatus for treating a flow of water containing contaminants includes first and second permeable electrodes and a power supply is coupled to each of the first and second permeable electrodes to create an electrical potential therebetween. The first and second permeable electrodes are disposed within the flow of water containing contaminants with the first permeable electrode upstream from the second permeable electrode and the water containing contaminants flowing through and between the permeable electrodes. The permeable electrodes are spaced a select distance to promote an electric current in the water containing contaminants between the electrodes sufficient to sustain oxidation or reduction of the contaminants in the vicinity of the electrodes. The electrodes are preferably substantially planar plates disposed in parallel and substantially normal to the direction of water flow. The distance between the plates is between about 0.001 and 1 meter. The electrodes are preferably made of a conductive material selected from the group including carbon black, vitreous carbon, graphite, stainless steel, aluminum, copper, gold and gold plated stainless steel.