Removal of tetrachloroethylene in an anaerobic fixed-bed reactor immobilized with Clostridium bifermentans DPH-1

An upflow fixed-bed reactor was evaluated for the removal of tetrachloroethylene (PCE) by a strictly anaerobic, PCE dechlorinating bacterium, Clostridium bifermentans DPH-1 immobilized on sterile ceramic beads. The ceramic beads provide a large surface area for development of cell mass in the column. For kinetic experiments, the conventional first-order reaction kinetics was applied to evaluate the batch and continuous immobilized reactors. Velocity constants (K_B and K_C) under the batch culture and continuous culture were determined to be 1.9 × 10^–2 (mg protein^–1h^–1) and 1.4 × 10^–2 (mg protein^–1h^–1), respectively. Maximum specific degradation rate of PCE was calculated as 0.16 (10^–3 μmol mg protein^–1h^–1 from average influent concentration of PCE (12 μM) in the bioreactor. Simultaneously maximum volumetric degradation rate was also computed as 10.2 μmol l^–1h^–1. The volumetric degradation rate was relatively higher than those of other reactors. In order to maintain the efficiency of PCE dechlorination, 20 h or more HRT in the reactor system was required.