Abstract
Feasibility of laboratory-scale bio-electrochemical reactor (BER) equipped with a multipleelectrode system (multiple BER) for treatment of nitrate-contaminated water was experimentally investigated with special attention to the optimum surface area of cathode. The multiple-electrode system was employed to enlarge the surface area of cathode so that improved reactor performance could be attained because of high contact efficiency among electron donor-H2, microorganisms and solution. Hence, the overall removal rate was increased with the increasing number of cathodes. However, the current-denitrification efficiency gradually declined with increasing current density. As a consequence, the electric energy consumption per removed nitrate was increased exponentially with current density. Thus, it was not reasonable to apply high currents for the multiple BER used in this study. An investigation on the optimum specific surface area of cathode, as a function of electric energy consumption, was carried out. Increasing number of cathodes resulted in the Ohmic potential drop due to the increasing distance between anode and cathodes. Also, the surface over-potential increased with the increasing current density. The appropriate specific surface area of cathode for the bioelectrochemical denitrification was estimated.
