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Oregon Breakthrough in Generating Electricity from Wastewater

The views expressed are those of the author and are not necessarily those of Scientific American.

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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:

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

Schematic of a portion of OSU's fuel cell technology

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.


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

Photo Credit:

  1. Photos of Hong Liu, an engineer and associate professor at Oregon State University, courtesy of Oregon State University and used with their permission.
  2. Schematic taken directly from the abstract of Yanzhen Fan, Sun-Kee Han, and Hon Liu’s journal paper.
Melissa C. Lott About the Author: An engineer and researcher who works at the intersection of energy, environment, technology, and policy. Follow on Twitter @mclott.

The views expressed are those of the author and are not necessarily those of Scientific American.

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Comments 7 Comments

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  1. 1. alan6302 11:28 am 08/14/2012

    I saw an article about turning poop to meat .That will likely be more important….. someday ( perhaps sooner than we like )

    Link to this
  2. 2. Raoul 11:47 am 08/14/2012

    alan6302, you know, roman army soldiers ate poops during their military campaings.

    Link to this
  3. 3. JRWermuth 6:31 pm 08/14/2012

    Is this process cost effective or simply green? Where can I find out what it would cost a city of 25K to implement and what would be the return? Simply reducing treatment costs on this island community would be a great benefit. More info – please – thanks

    Link to this
  4. 4. lpnetherton 8:23 pm 08/14/2012

    Bill Gates is working on a project to revolutionize the toilet; part of the solution must include generation of energy. Sounds like these folks need to get in touch with each other.

    Link to this
  5. 5. Melissa Lott 6:58 pm 08/16/2012

    Thanks for y’alls comments.

    @JRWermuth – The researchers on project are saying that this process is cost effective in the sense that it is projected to cost about the same as a traditional wastewater system (the ones we use today in the U.S.). AND, this doesn’t include the money that could potentially be made from the electricity that can be sold back to the existing grid for non-wastewater treatment activities.

    For an island community I imagine that this could be a great option, because you get electricity and clean water with the same system.

    That being said, this technology is going into the pilot project phase – meaning it’s not at the point where it could be used in a working plant (at least not yet). But, the potential is there.

    Link to this
  6. 6. choose 2:35 am 08/17/2012

    This can already be done with the bloom box fuell cell
    that I commented last time with the gas from the sludge that the wastewater digesters give out. So much for

    Link to this
  7. 7. Hanks 6:39 pm 09/7/2012

    Good luck to Dr. Liu on her demonstration project. My input would be that with decreased spacing she will need to watch out for rags, hair balls, and slime. Anything that projects into a sewage flow is inevitably covered with rags that are carried in the flow stream. Hopefully these will be successfully screened from her project. Hair also is captured by any intrusive object, and gets through screens and into the plant process. Slime will grow on any substrate that is introduced into the flow as the microbes anchor themselves to the “dinner table” and begin to metabolize the “food” in the flow stream. The process will need to include a cleaning phase to keep from clogging on slime building microbes, or pieces of slime that wash free. Sounds like a fun project.

    Link to this

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