EarthTalk is a Q&A column from E/The Environmental Magazine
Dear EarthTalk: Is there a way to utilize the energy in my dogs' poop? I have three dogs and lots of poop and would like to dispose of it in a "greener" manner. -- Mary C., Wallace, ID
No doubt creating a way to do so is possible, as large systems called anaerobic digesters (or biogas digesters) are often used in landfills to wring energy out of trash, as well as on some big farms and ranches where large amounts of cow manure provide plenty of feedstock. In such systems microbes generate methane gas -- which can be captured and used for power -- once they are set free on manure or trash. The economics of putting biogas digesters in landfills or big cattle operations can make the up-front expense tolerable -- money can be made or saved by selling or utilizing the resulting power -- but doing so in one's back yard might be a different story.
Not to say it can't be done: This past September artist Matthew Mazzotta, armed with a $4,000 grant from the Massachusetts Institute of Technology (MIT) -- where he earned a master's degree in visual studies last year -- created the ingenious Park Spark poop converter system that uses dog poop to power a gas lantern that illuminates a corner of the Pacific Street Dog Park in Cambridge, Massachusetts.
The system uses two steel, 500-gallon oil tanks, connected by diagonal black piping and attached to an old gaslight-style street lantern. "After the dogs do their business, signs on the tanks instruct owners to use biodegradable bags supplied on site to pick up the poop and deposit it into the left tank," reports Jay Lindsay on the Huffington Post. "People then turn a wheel to stir its insides, which contain waste and water. Microbes in the waste give off methane, an odorless gas that is fed through the tanks to the lamp and burned off." Although the park is small, neighborhood dog owners have provided enough waste for a steady supply of fuel.
The 33-year old Mazzotta got the idea after travelling in India and seeing people there using poop in small "methane digesters" to cook food. When he visited Pacific Street Park with a friend in 2009 and saw the park's trash can filled with bags of dog poop, the Park Spark idea was born. He hopes the installation, which was dismantled after its one-month run, has helped point out to people that there are potential energy sources all around us, and that we must consider every option at our disposal, so to speak, as we wean ourselves off oil in the face of impending climate change.
Besides reducing waste going to landfills, another environmental benefit of utilizing dog poop for energy is reducing one's carbon footprint. Burning methane derived from dog poop or other biodegradable waste material in an anaerobic digester is carbon neutral, meaning it doesn't contribute any new greenhouse gases into the atmosphere that could exacerbate global warming.
While it might not be worth $4,000 or a degree from MIT for you to create your own version of the Park Spark in your backyard, it's good to know that such technology exists, and will no doubt someday be available and affordable for the rest of us as long as we continue to find ways to reduce, reuse and recycle everything we possibly can.
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