March 3, 2004 -- Environmental engineers at Pennsylvania State University (Penn State; University Park) have developed a prototype microbial fuel cell (MFC) that can generate electricity while treating wastewater, according to press statements issued Feb. 23 by the university and the National Science Foundation (NSF), which funded the project.
Although the research to date has been conducted on a small scale using wastewater skimmed from a treatment-plant settling pond, the process shows promise as a means of reducing wastewater treatment costs worldwide, its developers say.
"MFCs may represent a completely new approach to wastewater treatment," said Bruce E. Logan, a professor of environmental engineering at Penn State and director of the project, according to the university press statement. "If power generation in these systems can be increased, MFC technology may provide a new method to offset wastewater treatment plant operating costs, making advanced wastewater treatment more affordable for both developing and industrialized nations."
The MFC developed for the project is about 150 mm (6 in.) long and 63.5 mm (2.5 in.) in diameter and contains eight graphite anodes, according to the NSF press statement. Bacteria from the wastewater adhere to the anodes and release electrons during the treatment process, the statement says.
"A fuel cell operates akin to a battery, generating electricity from a chemical reaction," the statement explains. "But instead of running down unless it's recharged, the cell receives a constant supply of fuel from which electrons can be released. Typical fuel cells run off of hydrogen. In a microbial fuel cell, bacteria metabolize their food - in this case, organic matter in wastewater - to release electrons that yield a steady electrical current."
The Penn State experiments to date "have produced between 10 and 50 milliWatts of power per square meter of electrode surface, or about 5 percent of the amount needed to run one mini-Christmas tree light, while removing up to 78 percent of organic matter as measured by biochemical oxygen demand," the university press statement notes. Previous research has shown that MFCs can produce electricity from water containing pure chemicals, but the Penn State research is the first to demonstrate that MFCs can produce electricity directly from wastewater, according to the statement.
A research paper describing the project is scheduled for publication in a future edition of the journal Environmental Science and Technology. A prepublication version ("Production of Electricity During Wastewater Treatment Using a Single Chamber Microbial Fuel Cell") is available free to the journal's subscribers or may be purchased by nonsubscribers at:
http://pubs.acs.org/journals/esthag/index.html
(select the "Research ASAPs" tab, then see the section titled "Web Release Date: February 21, 2004"). For more information, send e-mail to Logan at [email protected].
