Electrochemical processes are the most adequate tools in the aqueous effluent treatment. The process will not require chemical addition and indeed electrons are the only reactants added to the process to stimulate the reaction. Anodic oxidation of recalcitrant wastewater in a typical electrochemical set-up is particularly interesting because of its ease of operation and scope for scale-up. Nevertheless, electro oxidation in the three-dimensional carbon bed electrodes is a promising process for electrooxidation of effluents containing non-biodegradable organic compounds. The application of three-dimensional carbon bed electrochemical reactor for the degradation of organic pollutant is demonstrated in this chapter. The role of carbon particles in the three-dimensional electrodes reactor is described in this chapter. It has at least two important functions: 1) adsorption of organic compounds from effluents and 2) act as particle electrode. Various operation and design considerations leading to better understanding of carbon bed electrochemical reactors are discussed.