A hybrid biofilm reactor for nitrate and pesticide removal

The feasibility of a hybrid biofilm reactor for nitrate and pesticide removal was demonstrated experimentally and theoretically. The reactor consists of an outer cylindrical cathode on which denitrifying autotrophic biofilm was attached and an inner anodic compartment packed with GAC. A bactericide, isoprothiolane (IPT), was used as a model pesticide, which inhibited the biological reduction step of N₂O to N₂. In the hybrid biofilm reactor, however, IPT was removed effectively by the GAC anode so that complete denitrification was achieved without accumulation of N₂O. Simultaneous removal of nitrate and pesticide was evaluated by a mathematical model based on a simplified inhibition kinetics and Langmuir adsorption isotherm. Calculation results using the model were in fairly good agreement with experimental results.