A relative-least-squares technique to determine unique Monod kinetic parameters of BTEX compounds using batch experiments

An analysis of aerobic m-xylene biodegradation kinetics was performed on the results of laboratory batch microcosms. A modified version of the computer model BIO3D was used to determine the Monod kinetic parameters, kmax (maximum utilization rate) and KS (half-utilization constant), as well as the Haldane inhibition concentration, KI, for pristine Borden aquifer material. The proposed method allows for substrate degradation under microbial growth conditions. The problem of non-uniqueness of the calculated parameters was overcome by using several different initial substrate concentrations. With a relative-least-squares technique, unique kinetic degradation parameters were obtained. Calculation of the microbial yield, Y, based on microbial counts from the beginning and the end of the experiments was crucial for reducing the number of unknowns in the system and therefore for the accurate determination of the kinetic degradation parameters. The kinetic parameters obtained in the present study were found to agree well with values reported in the literature.