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Biofuels wastewater could become major source of renewable biofuels

Published on March 5th, 2011 | by Tina Casey

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U.S. Flushes 12.5 Trillion Gallons of Energy Down the Drain Every Year

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March 5th, 2011 by  

wastewater could become major source of renewable biofuelsResearchers from Newcastle University in the U.K. have done the math, and on the surface it looks pretty grim. Every year, the U.S. flushes about 12.5 trillion gallons of energy right down the drain. They’re actually talking about potential energy, in the form of biofuels that could be recovered from wastewater.  That alone could form a big part of the renewable energy picture, but wait there’s more – much, much more.

Renewable Biogas from Sewage

Regular readers of Cleantechnica are probably used to us raving about the energy potential in wastewater (yeah, sewage). Sewage-to-methane biogas equipment is becoming commonplace at treatment plants, where it is usually used to run equipment at the site. The City of San Antonio recently bumped it up a notch by selling its sewage biogas into a commercial pipeline, and we should also note that agricultural biogas is becoming a big deal, too. The U.K. researchers estimate that a gallon of wastewater contains enough energy potential to run a 100-watt light bulb for five minutes, which doesn’t sound like all that much until you multiply that by 12.5 trillion.

More Good Stuff from Sewage

In addition to biogas, sewage can yield a plethora of renewable benefits. Depending on the presence of contaminants, it can be dewatered and used as a natural soil amendment. Researchers are also looking into refining biofuel from the “trap grease” in sewage, and even making renewable bioplastics from sewage. To ice the cake, the typical treatment plant is a sprawling facility often located in a relatively remote area, providing the potential for wind turbines and solar power installations – and let’s not forget the potential for kinetic hydropower, too.

Who’s Afraid of $4 Per Gallon Gas?

Sewage-to-biogas isn’t the answer to all of our nation’s energy woes, but exploiting the energy potential of wastewater is going to play a big role in a diverse, renewable energy picture – and it’s locally sourced, too. We’re dealing with yet another price spike at the gas pump right now, but the time is fast approaching when the U.S. economy will no longer march in lockstep with global market trends for a single type of energy.

Image: Green bucket by Dwstucke on flickr.com.

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About the Author

Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • Wayne Williamson

    The numbers seem way out of line…I wish you had posted a link to their report…
    Basically its stating that I produce ~40,000 gallons a year of waste(12.5t/360m)…and each of those gallons could produce ~8 watts(100/(60/5)…
    Believe it or not, the 40k of water sounds about right but the actual “solids” are probably closer to 200 gallons(way over estimating;-)
    The end result is that they are off by a factor of 1 thousand and probably much more….

  • http://www.sjvcleanenergy.org Mike Nemeth

    “To ice the cake,” nice turn of a phrase on an interesting study.

  • Dr.A.Jagadeesh

    Good Article.Renewables can play a crucial role in Energy Mix of US.

    Dr.A.Jagadeesh Nellore(AP),India

    • John

      Not everyone in the US thinks that the world revolves around the US Dr. A. Jagadessh Nellore.

      The worlds energy infrastructure needs to change. We are in this together.

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