| During the past two decades, soil and groundwater contamination due to leakage and spillage of petroleum hydrocarbons has been a major environmental concern of the oil industry. Therefore, effective remediation technologies are desired to clean up petroleum contaminated groundwater and the associated soil system.;Several PAH-degrading bacteria from a western Canada oil contaminated site, with the potential of biosurfactant production, were screened. Among the bacteria, strain C-203-2, classified as Acinetobacter lwoffii , was chosen and applied in order to explore the biodegradation kinetics of PAHs under the combined effects of both biosurfactant and DOM. All biodegradation data were fitted well with a modified Monod equation. With the combined presence of both DOM and biosurfactant, the degradation of PAHs would be significantly enhanced in comparison with only the presence of biosurfactant, which is due to the formation of DOM-biosurfactant complex micelles.;Finally, an integrated mathematical modeling system, simulating biosurfactant-enhanced bioremediation processes, was developed. The model includes modules of multiphase multicomponent flow and transport, biological degradation, and biosurfactant-enhanced remediation. The developed mathematical model is effective in examining the coupled effects of biodegradation and biosurfactant-enhancement within a multiphase multicomponent transport framework.;This study was a first attempt to explore the combined effects of soil components and biosurfactant on the fate and transport of PAHs. The research should be helpful in broadening the knowledge of fate and transport of PAHs in subsurface and can be used to support the bioremediation of petroleum-contaminated sites.;In this dissertation research, a number of methodologies and mechanisms aimed at biosurfactant enhanced in-situ bioremediation of petroleum pollutants have been advanced. In particular, the fate and transport of petroleum contaminants such as PAHs and BTEX in the subsurface environment, with consideration given to both soil properties and added biosurfactant were systematically investigated. In detail the combined effects of both DOM and biosurfactant on the solubilization and sorption/desorption behavior of phenanthrene (PHE) and pyrene (PYR), in a soil-water system, were systematically investigated. Two types of DOMs (derived from soil and bio-composting) were applied in this research. There was significant enhancement of solubility and thus desorption for both PHE and PYR in systems with concurrent DOM and biosurfactant, as compared with systems having merely biosurfactant or DOM. This is due to the various specific molecular structures and functional groups of two DOMs. Also, the solubility and desorption of PAHs in a compost-DOM system was higher than in a soil-DOM system. This can also be explained as the differences in specific molecular structures and functional groups of the two DOMs. |
