The effectiveness of electrochemical reactors for industrial wastewater treatment has been improved since three-dimensional electrodes have been introduced; in fact, limitations of mass transfer can arise, due to the low concentrations of pollutants which may be involved in the process. Three-dimensional electrodes offer a very high electrode area per unit electrode volume and they can act as turbulence promoters or give rise to high linear electrolyte velocity, resulting in high values of mass transport coefficient. However, careful selection of operative parameters is needed in order to obtain high performance. This paper examines the results obtained in our laboratory on the cathodic reduction of copper at RVC electrodes; in particular the interference of dissolved oxygen is studied during the removal of copper from extremely diluted solutions (C < 10 ppm). Some results are also discussed on the removal of organic pollutants by electrochemical oxidation at three-dimensional anode consisting of a fixed bed of carbon pellets.