Oxidative Degradation of PCEITCE Using KMnO4 in Aqueous Solutions under Steady Flow Conditions

The rates of oxidative degradation of perchloroethene (PCE) and trichloroethene (TCE) using KMnO4 solution were evaluated under the flow condition using a bench-scale transport experimental setup. Parameters which are considered to affect the reaction rates tested in this study were the contact time (or retention time), and the concentration of oxidizing agent. A glass column packed with coarse sand was used for simulating the aquifer condition. Contact time between reactants was controlled by changing the flow rate of the solution through the column. The inflow concentrations of PCE and TCE were controlled constant within the range of 0.11 similar to 0.21 mM and 1.3 similar to 1.5 niM, respectively. And the contact time was 14 similar to 125 min for PCE and 15 similar to 36 min for TCE. The KMnO4 concentration was controlled constant during experiment in the range of 0.6 similar to 2.5 mM. It was found that the reduction of PCE and TCE concentrations were inversely proportional to the contact time. The exact reaction order for the PCE and TCE degradation reaction could not be determined under the experimental condition used in this study. However, the estimated reaction rate constants assuming pseudo-1st order reaction agree with those reported based on batch studies. TCE degradation rate was proportional to KMnO4 concentration. This was considered to be the result of using high inflow concentrations of reactant, which might be the case at the vicinity of the source zones in aquifer. The results of this study, performed using a dynamic flow system, are expected to provide useful information for designing and implementing a field scale oxidative removal process for PCE/TCE-contaminated sites.