DETERMINATION OF MONOD KINETIC COEFFICIENTS FOR VOLATILE HYDROPHOBIC ORGANIC-COMPOUNDS

A new procedure is presented to determine Monod kinetic coefficients a nd the microbial yield coefficient for volatile hydrophobic compounds such as phenanthrene. Batch experiments were conducted with a mixed cu lture capable of degrading phenanthrene. The phenanthrene disappearanc e and carbon dioxide production were monitored with time. A maximum li kelihood estimator was formulated to fit the set of equations that des cribe the system to the measured data. The model takes into account a number of processes such as partition onto the apparatus, volatilizati on, and partition onto the biomass. The parameters required to describ e these processes were obtained by independent experiments. The yield coefficient could be determined within a small range. However, the spe cific growth Fate and the half-saturation constant were found to vary widely, with pairs of them describing the system adequately. It was sh own that partition and volatilization processes can significantly affe ct the determination of the yield and Monod kinetic coefficients and n eed to be taken into account. (C) 1996 John Wiley & Sons, Inc.