|Title||Aerobic soil microcosms for long-term biodegradation of hydrocarbon vapors|
|Publication Type||Journal Article|
|Year of Publication||1992|
|Authors||Richards RJ, Ostendorf DW|
|Journal||Hazardous Waste and Hazardous Materials|
The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas Chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from these microcosms. The results were applied to a mathematical model from which rigorously controlled estimates of Michaelis-Menten type maximum rate parameters were produced. The latter were compared to independently derived estimates of the same kinetics parameter, and were used to establish whether any depth-dependence on this parameter exists. The maximum rate parameter value for the mid-depth soil range was found to be a successful test of previously acquired field data.
A major problem encountered in the measurement of hydrocarbon vapors involves the difficulty in holding vapors within a container such as a microcosm vial over extended periods of time. The application of an exterior water seal successfully solved this problem, with outstanding results. The water seal allowed for long term measurement of hydrocarbon vapor biodegradation rates using gas chromatography. A mathematical analysis of the resulting data was used to establish soil depth-related values for the Michaelis-Menten type maximum rate constant. The results of previous studies on soil from the same site compared well with those of this project, and the existence of a depth-dependence on the maximum rate constant was confirmed.