Parameter Determination of Sequential Reductive Dehalogenation Reactions of Chlorinated Hydrocarbons

Abstract

Chlorinated hydrocarbons such as tetrachloroethylene (PCE) and trichloroethylene (TCE) are not directly mineralized, but rather are transformed into one or more intermediate compounds before converting into a final compound. Since the biotransformation rate coefficients of each intermediate compound are different, the coefficients in each step of reductive dehalogenation must be determined to establish an effective treatment operation. These parameters can be estimated by fitting the experimental data to Michaelis–Menten equation. In this study, we introduce a methodology, using both the curve-fitting and graphical methods, to estimate the rate of maximum biotransformation and half-saturation coefficients of parent and intermediate compounds. First-order rate coefficients are also estimated by simplifying the Michaelis–Menten equation for both curve-fitting and graphical methods. The results show that both methods produce similar parameter values for each rate equation. Estimated first-order kinetic parameters are employed to predict the compound concentrations from the analytical solutions of governing equations for sequential dehalogenation. Comparisons of predicted and experimental values show favorable agreement.