cathode 7 is shown which includes an circular 3d foam type electrode 15 retained in an insulating electrode holder having a top 16 and bottom 18 see fig1 held together with screws 17 each electrode holder is sized to provide a snug fit within the tubular body 2 so that essentially all wastewater introduced into the reactor passes through the porous anodes 8 and cathodes 7 fig3 shows a foam type electrode 15 and contact wire 9 between the top 16 and bottom 18 of the electrode holder prior to assembly by screwing the top 16 and bottom 18 together with the screw 17 in use the reactor 1 can be mounted vertically or horizontally the reactor should be placed in an open recirculation circuit thus allowing evolved gases such as carbon dioxide to escape the body of the reactor can have a variety of shapes but preferably is tubular and the internal chamber cylindrical with a generally circular cross section while fig1 shows detachable inlet and outlet ports 3 and 4 which permit convenient access to the electrodes in the tubular body 2 a unitary construction is also possible the electrode holder see fig3 serves as a mechanical device to install electrodes within the electrochemical reactor 1 as well as an electrical insulator the insulating holder preferably is sized conveniently in a disc shape for close fitting insertion into the internal.