Scientists: Wastewater Can Be An Energy Superstar

If Oregon State University researchers can take their new work on turning wastewater into electricity from the lab to real world, we might be looking at an energy revolution. No, really: The scientists say their new microbial fuel cell could not only power wastewater treatment plants, but turn those plants into power stations.

That energy can be produced from wastewater isn’t a novel idea — there are anaerobic digestion systems at work right now taking advantage of the methane derived from wastewater treatment. One plant in California feeds captured and cleaned-up methane right into the natural gas pipeline, while another converts the biogas to hydrogen that goes for two uses: in a fuel cell to produce electricity that powers the treatment plant, and to a fuel-cell vehicle fueling station.

Researcher Hong Liu (image via Oregon State University)

Hard to argue with either of these systems, but the Oregon State scientists say that based on their new work, it’s clear that a different technology – microbial fuel cells, or MFCs – holds out far greater energy-producing potential.

The researchers say that by applying several new concepts to MFCs, they can produce 10 to 50 times the electricity than had been seen in other wastewater-treatment/MFC research.

“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,” Hong Liu, an associate professor in the OSU Department of Biological and Ecological Engineering, said in a statement. “This could have an impact around the world, save a great deal of money, provide better water treatment and promote energy sustainability.”

Simply powering the treatment plants would be an achievement; the university estimates that “3 percent of the electrical energy consumed in the United States and other developed countries is used to treat wastewater, and a majority of that electricity is produced by fossil fuels that contribute to global warming.”

MFCs share a characteristic with anaerobic digestion – both technologies rely on bacteria acting on organic waste. But instead of using the gas produced, MFC’s harvest the electrons. They run from the anode to the cathode in the fuel cell to create an electrical current.

The Oregon team pointed to three advances that help crank up the energy-producing power of their MFC: reduced anode-cathode spacing, evolved microbes and new separator materials. The researchers said all this led to electricity production in the lab of more than two kilowatts per cubic meter of liquid reactor volume – an amount that “far exceeds anything else done with microbial fuel cells.”

The Oregon research was funded by the National Science Foundation and published in the journal Energy and Environmental Science. The next step in advancing the technology is to do a pilot study.

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.


  • Reply August 14, 2012


    I wonder if it could be scaled down to something you could fit in an automobile– imagine filling your gas tank from your septic tank each week! Sure sounds like technology worth funding! Go OSU!

    • Reply August 16, 2012


      2 kw/ square meter wouldn’t get a heavy car very far – 1 hp is .746kw so a 200hp car is 149.2kw all within a few cubic meters. Maybe they could layer it to maximize surface area but i’d imagine it would get hot and require a lot of storage to put out 150 kw for more than a few hours. Electricity fed to the grid during peak hours is better spend anyway. We just need to find a way for cars to run off the existing grid around them as they drive…

Leave a Reply