From: Green Beer

The Potential of MFCs

Microbial fuel cells (MFCs) at their most fundamental work like large batteries. Wastewater flows through the MFCs’ anode compartments where bacteria eat leftover sugars and starches. This produces a chemical energy that transfers to the cathode side of the battery. The batteries recharge themselves so that they are constantly releasing energy. Because this process produces clean water through the removal of organic material, manufacturers can also use MFCs as a way to treat their wastewater streams.

Because they are relatively simple and because they have such potential, MFCs have begun earning a reputation as a new and promising method of generating power.

Bruce Logan, professor of environmental engineering at Penn State University, in University Park, PA, has long studied MFCs and, like others who’ve researched the cells, says that the products have enormous potential, because they do perform two important tasks—the generation of energy and the treatment of wastewater—at the same time.

Logan says he expects to see a growing number of MFC test programs because the fuel cells can work with the waste streams at such a wide range of manufacturing plants.

“MFCs are perfect for virtually any plant that has a wastewater stream that is rich in biodegradable organic matter,” he says. “Breweries are good, because they get so much popular press. Beer and electricity—that’s good press. But even domestic animal wastewaters are fine, too. The process is not so important. What is important is the fact that there is organic matter in the wastewater.”

Logan hopes to spread the word about MFCs in his new book, Microbial Fuel Cells, published in 2008 by John Wiley & Sons. The time is right to experiment with MFCs, because the cells’ ability to convert organics into usable energy is especially important, as governments wrestle with the challenges presented by the limited and volatile supply of fossil fuels at their disposal, says Logan.

All that MFCs need is more time and study, he adds, as the main challenge keeping MFCs from becoming a viable alternative is the fact that scientists have not yet discovered a way to use them on a large-scale basis.

Logan, though, is confident that this hurdle can be overcome with more study and pilot programs.

“This is still a brand new technology,” he says. “The work on MFCs didn’t start in earnest until about 2004. Given that, it’s already come a long way for what is still a young technology.”

Federal agencies need to invest more money in MFC research, Logan says, to spread the word that the cells can make an impact in the way companies produce energy.

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MFCs shouldn’t be a hard sell. It costs manufacturers money to treat wastewater. They should appreciate a technology that can provide them a useful product from something that they already have to put money into. And not only do MFCs do this, they also can help plants reduce the amount of wastewater they have to treat.

“It’s like solar energy,” says Logan. “It took a long time for solar to become commercially viable. It looks very promising for MFCs at this time. I think we still need to consider the materials and the cost of these materials. But aside from that, this looks like a very promising technology.”