The Science of Sustainability

From Waste To Watts: Biofuel Bonanza

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It may look like waste, but to some people it's green power. Find out how California dairy farms and restaurants like Jardinière are taking their leftover waste and transforming it into clean energy.

You may view the "From Waste To Watts: Biofuel Bonanza" TV Story online, as well as find additional links and resources. Also, you can see additional photos for this story.

Amy Miller is a Coordinating Producer for television on QUEST.

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Category: Chemistry, Environment, Television

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About the Author ()

Amy Miller is the Supervising Producer and Partner at Spine Films, a boutique independent production company specializing in hard science factual television. Prior to joining the Spine team, Amy worked for six years at KQED (PBS) in San Francisco as the Series Producer of QUEST, a multimedia science and environment series. It was at KQED that she was finally able to merge her lifelong passions for science and storytelling. Originally from Iowa, Amy grew up in Colorado then landed in San Francisco in 1991. She studied biology and film production at University of Colorado and San Francisco State University, and since graduating in 1995, she has worked as a camera assistant, documentary filmmaker, TV producer and correspondent on a variety of cable and public television shows including two other KQED series, "Spark" and "Independent View". For her work in television, she has earned ten regional Emmy awards, two AAAS Kavli Science Journalism awards, and a Society of Professional Journalists Excellence in Journalism Feature Writing award.
  • Marc

    An interesting story, but it isn't clear to me what happens to the material in the digester after the microbes have done their job. Does the material have value as fertilizer? Or have the microbes eaten all of the potential soil nutrients? Where does it go?

  • Craig Rosa

    Good question. As I understand it, the material is at least in part re-used as bedding for the cows.

  • joelsk44039

    Our company is taking a different approach. We have done preliminary testing of dairy manure to determine if it is suitable as a feedstock fuel for gasification. This process heats the manure in a near zero oxygen environment at which it dissociates as gas — syngas, to be exact — consisting mostly of Carbon Monoxide and Hydrogen. These are taken off the reactor vessel and burnt instantaneously to produce heat and water vapor. The heat is used to make steam for the production of electricity. The excess heat created by the synthesis of Carbon Monoxide is used to dry the manure feedstock. The residue of non-volatile material, including Potassium, Calcium, Phosphorus and other materials, may be used as a filler for concrete or asphalt, for land application as a "soil amendment," or for certain industrial processes. We sell it to end users, creating additional income.

    The process is very efficient, using nearly 90% of the intrinsic heat in the manure for the production of heat, hot water, steam and/or electricity. The same system can be used for any organic material, whether renewable, like crop wastes, paper and food waste, or non-renewable like tires, plastic and auto "fluff."

    We can be reached at for more information.