NSF Project

Improving Power Generation in Microbial Fuel Cells

Bruce Logan , Dept. of Civil and
Environmental Engineering Tom Mallouk, Dept. of Chemistry
Funding: National Science Foundation, BES-0401885(November 15, 2004 - October 31, 2007)

Project Summary

In this project we are investigating factors that need to be better understood in order to increase power generation in microbial fuel cells. With this information, we will determine how to make the process more efficient and economical. For example, because we expect that the anode surface area limits power generation, we will determine how much we can decrease the area of the cathode in order to reduce cost, and will look at such factors as electrode spacing and orientation. We will examine other ways to reduce the cost of building MFCs. It may be possible to lower the amount of Pt on the cathode or even use different materials. We have shown that a proton exchange membrane (PEM) is not needed for a MFC, but this material can provide other advantages such as keeping the bacteria from the Pt cathode surface. We are examining other materials and coatings for this purpose. We will also investigate what components of a wastewater are mostly likely to provide suitable energy sources for generating electricity. The ultimate goal of this research is to find new and novel MFC designs that will provide the basis for the creation of new, more efficient and economical reactor designs to harvest energy from wastewater. We will devise and test new prototype systems based on designs suitable for scale up to larger systems.

The results of this research will provide a completely new avenue of wastewater treatment based on using bacteria to produce electricity from waste organic matter. The results could be of immediate economic benefit to communities and industries by reducing or even eliminating net costs for wastewater treatment. In the US, for example, human wastes produced annually contain 3.4 ´1010 kWh of energy worth $2 billion. Eliminating the need for expensive wastewater aeration, by using direct-air MFCs, could save an additional $7 billion. It is hoped that development of low-cost MFCs will lead to direct biomass-based electricity generation from crops grown in the US that could reduce our national dependence on fossil fuels and avoid a net production of CO2 emissions that contribute to global warming.