Feasibility of using microbial fuel cell technology for bioremediation of hydrocarbons in groundwater

Abstract

A single-cell microbial fuel cell (MFC) design was used to study anaerobic microbes that utilize petroleum contaminants as a sole substrate to produce power during remediation. Additionally, we tested various proton bridge designs to physically separate the anode and cathode chambers of a two-cell MFC by ∼ 9 m (∼ 30 ft.). This separation enables the potential use of MFC technology for in situ bioremediation of petroleum hydrocarbons in the groundwater, in which oxygen is usually depleted and oxygen availability only exists at or near the surface. Sustained power generation (as high as 120 mW/m² cathode) was recorded for ∼ 6 d in a single-cell MFC utilizing a mixture of refinery waste (containing various concentrations of hydrocarbon contaminants) and cell growth media. MFC cell potential (1KΩ external resistance) decreased by ∼ 55% over the length of the 9 m proton bridge with a 6.9% decrease in potential per m of bridge. This preliminary data indicates that using MFC technology (with our modifications) may enhance bioremediation of petroleum contaminants in groundwater under anaerobic conditions. Because oxygen is eventually used as the terminal electron acceptor for anaerobic biodegradation inside an MFC, this technology may be a cost-effective innovation to enhanced biodegradation in groundwater, by substituting or eliminating conventional in situ aeration. To our knowledge, this is the first report on power generation from MFCs utilizing mixed hydrocarbon substrates. In addition, this study is the first to show the applicability of using extended proton bridges for the physical separation of anode and cathode chambers over extended distances that may be encountered in the field.

Keywords:

• Bioremediation
• groundwater
• microbial fuel cell
• hydrocarbons

Acknowledgments

We thank Jeff Cooper, Joel Mason, and Jesse Newcomer at Western Research Institute (WRI) for conducting chemical analyses and providing technical assistance with this project. We also thank Dr. Bruce Logan (Pennsylvania State University) for technical assistance with initial system design. Financial support for this research was provided by the United States Department of Energy (DoE) through WRI's Cooperative Agreement No. DE-FC26-98FT40322 with DoE. Any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not reflect the view of the DoE.

This paper was presented at the SETAC Asia/Pacific 2006 conference held at Peking University, China on September 18–20, 2006.

Notes

^a GRO = compounds eluting with n-alkane markers ranging in size from C-4 to C-10.

^b DRO = compounds eluting with n-alkane markers ranging in size from C-10 to C-18.