Comparative study on the bio-electrochemical denitrification equipped with a multi-electrode system

Three biofilm-electrode reactors (BERs) with multiple cathodes were applied to investigate the effect of electrode configuration and flow direction on denitrification under laboratory-scale conditions. The distribution of nitrate, DO and pH varied among applied BERs, as a consequence of a different electrode position in the reactors, bringing about a difference in the performance. Flow-through configuration of electrodes with a downstream anode appears to be the most suitable configuration since nitrite did not accumulate in the effluent only in this experiment and the current-denitrification efficiency at low current densities was high. Thus, it is recommended for a low-loading operation.