Abstract
There is a great need for effective, simple, and less costly remediation systems in the petroleum industry for the removal of hydrocarbons from contaminated aquifers. While intrinsic bioremediation is a cost-effective approach to clean-up of hydrocarbon-contaminated aquifers, the rates of natural degradation can be too slow or insufficient to prevent substantial migration of the contaminant plume. Aerobic remediation is often not a feasible strategy because oxygen is poorly soluble in water and difficult to transfer into the subsurface. In a contaminated aquifer, the activity of anaerobic bacteria is usually not limited by the ability to biodegrade contaminants, but rather by nutrients and electron acceptor availability. To that end, the major goal of this proposal is to design and implement a simple bioremedial scheme to enhance the anaerobic biodegradation of benzene and other hydrocarbons by injecting inexpensive highly soluble nutrients, including sulfate as an electronic acceptor, at strategic locations within the contaminant plume to prevent the migration of hydrocarbons.
The study site will be a hydrocarbon-contaminated aquifer at the Conoco oil refinery in Ponca City, Oklahoma. Information garnered from laboratory experiments will be critical for designing and optimizing the field component of this study. Batch and column experiments using contaminated material from the site will be conducted to optimize the anaerobic biodegradation of hydrocarbons. Priority will be given to identifying the conditions that stimulate benzene biodegradation due to its toxicity, regulatory concerns, and prevalence at this site. After the laboratory experiments are completed, a full-scale field trial will test the technology at the Ponca City refinery.
The proposed bioremedial scheme, using sulfate as an election acceptor, represents a novel approach to remediating anaerobic, hydrocarbon-contaminated aquifers. Basic laboratory research will be conducted by Surbec Environmental in conjunction with the University of Oklahoma. The University will provide much of the scientific knowledge necessary for process design, while Surbec Environmental has the field experience to implement and evaluate the technology. Conoco has expressed much interest in helping to evaluate and develop a cost-effective remedial scheme, such as the one proposed here, and will contribute matching funds for this project.