The use of bio-electric systems for contaminant remediation

Hydrocarbon contamination of shallow aquifers is particularly important in urban areas because of their constant emission, persistence, and their potential health and environmental impacts. This research is motivated by the occurrence of creosote-contaminated sites in BC, where natural anaerobic biodegradation is taking place, and is inspired in the technology used in bio-electrochemical systems. Bio-electrochemical systems are devices that take advantage of the ability of microorganisms to transfer electrons to solid electrodes and generate an electrical current. Their main application is aimed at electricity production in the so called microbial fuel cells. However, the same principles can potentially be used to develop a new remediation technology to foster the oxidation of reduced contaminants. This would be accomplished by inserting an electrode pair into a contaminated aquifer, connecting the reducing and the oxidizing zone; the anode would be introduced in the reducing zone where the contamination resides, whereas the cathode would be located in the oxidizing zone. Microbial oxidation of the reduced contaminants would be attained by using the anode as an additional electron acceptor, which would increase the rate of contaminant degradation. This presentation will provide a brief introduction to bio-electrochemical systems, their potential application to contaminant remediation, and will address the early results of laboratory experiments exploring the feasibility of using electrodes to remediate hydrocarbons in reducing environments.