Power from the People: Sewage to Energy
If you read my last entry, you know how I’m feeling about GHG emissions, climate change, and a few of the things we’re doing at home to try to reduce our energy consumption and related impacts. But the changes are not just happening at home. I’ve long known been intrigued with the possibilities of energy capture from sewage, but recently it seems that the concept is moving closer to a reality.
In late 2011, the Water Environment Federation, the well-respected industry association that represents 35,000 sewage treatment professionals, adopted the position that “Wastewater treatment plants … have the potential to reduce the nation’s dependence on fossil fuels through the production and use of renewable energy” as well as through more standard energy conservation measures. In 2012 WEF took this one step further by releasing their “Energy Road Map”, a guidepost for utilities who want to work towards reducing their energy consumption and capturing energy from their wastestream, all with the goal of becoming either energy-neutral or even energy suppliers. Because sewage treatment operations are frequently one of the largest greenhouse gas emitters in a municipality, this is a big deal.
There are a number of utilities leading the way including the one right in our nation’s capitol. In December I had the opportunity to visit DC Water, home to the world’s largest sewage treatment facility. General Manager George Hawkins and Engineer Ryu Suzuki were enthusiastic hosts, proudly showing the CAMBI digesters that, once complete, will offset much of the energy use at the plant while also cutting in half the volume of sludge that needs to be trucked offsite.
While there, I asked about the relatively new ‘anammox‘ process I had read about in the 10 August 2012 issue of Science magazine. (Note – if I could figure out how to insert it here I would, but I can’t!) Ryu told me that the treatment plant in Hampton Roads, VA is applying it, but DC Water’s sewage isn’t the right consistency for the anammox bacteria. So, DC Water is actively engaged in research to try to figure out how they can modify this new process and apply it for their circumstances. thus gaining even more energy from their sewage. Ryu and others have told me that anammox will be a ‘game changer’ for sewage treatment and energy capture. For another perspective, check out this TEDx talk by Kartik Chandran of Columbia University which illustrates a dizzying array of biofuels, organic chemicals, and fertilizers that can be captured from human “waste”.
While each of us does out part at home, it’s great to know that there are smart, enthusiastic engineers and sewage geeks out there helping us to make change on a larger scale, capturing power with every flush. We’re talking about a revolution – a sewage revolution.