About 3 percent of the electricity consumed in the United States and other developed nations is used to treat wastewater. But, a technology breakthrough from engineers at Oregon State University could be a key in turning the world’s waste treatment facilities into mini-power plants.

A technology developed by OSU engineers could allow wastewater treatment facilities to produce 10-100 times more electricity (per volume) than previous technologies and approaches. In turn, according to a journal article published in Energy and Environmental Science, large microbial fuel cells could be used to improve the sustainability of the wastewater treatment process.

This approach used by the OSU researchers can be broken down into following steps:

Bacteria oxidize the organic matter (a.k.a. poop, milk, etc) This oxidation process produces electrons These electrons flow from the fuel cell’s anode to its cathode This flow of electrons creates an electrical current

OSU’s new microbial fuel cell technology uses reduced anode-cathode spacing, evolved microbes and new separator materials to improve the amount of energy that it can harvest from the organic mater. These improvements allow the fuel cell to produce electricity more efficiently than with anaerobic digestors (which is essentially a process of recovering methane gas from decomposing waste) - and actually treats the wastewater more effectively.

Dr. Hong Liu, an associate professor in the OSU Department of Biological and Ecological Engineer and lead faculty member behind this project, is now seeking funding for a pilot study of this fuel cell technology. Her research team estimates that, at commercial scale, the cost of this new technology would be comparable to that of today’s commonly used activated sludge systems, even if one neglects the value of excess electricity sales. According to Dr. Liu:

"If this technology works on a commercial scale the way we believe it will, the treatment of wastewater could be a huge energy producer, not a huge energy cost…This could have an impact around the world, save a great deal of money, provide better water treatment and promote energy sustainability.”

This technology breakthrough might be even more valuable in developing nations, where sewage treatment can be a challenge due to limited access to consistent electricity supplies. But, even in the developed world, the potential value of this more sustainable wastewater treatment system is quite exciting.

References:

Oregon State University (2012, August 13). A new energy source: Major advance made in generating electricity from wastewater. ScienceDaily. Retrieved August 13, 2012, from http://www.sciencedaily.com­ /releases/2012/08/120813155525.htm Yanzhen Fan, Sun-Kee Han, Hong Liu. Improved performance of CEA microbial fuel cells with increased reactor size. Energy & Environmental Science, 2012; 5 (8): 8273 DOI:10.1039/C2EE21964F

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