for National Geographic News
Your house powered by pooch poop?
The idea may sound far-fetched, but officials in dog-friendly San Francisco, California, hope to harness the power of methane in doggie doo so it can be used for heating homes and generating electricity.
The technology of turning animal waste into energy was introduced in Europe some 20 years ago. It's practiced by hundreds of farms there, as well as by 16 U.S. dairy farms.
But San Francisco is believed to be the first U.S. city to explore the energy potential of pet waste.
In a pilot program to start this year, Norcal Waste, a garbage company that collects the city's trash, plans to use biodegradable bags and dog-waste carts to pick up the poop in one of San Francisco's most popular dog parks.
The waste will be run through a methane digester, a tank in which bacteria break down the feces to create methane. This biofuel can then be piped directly to a gas stove, heater, or anything else powered by natural gas.
"Scraping dog poop off your shoe, now that's something most people have been frustrated with for a long time," said Robert Reed, a Norcal spokesperson.
"Now we have an opportunity to turn this nuisance into something positive."
From Food Scraps to Dog Doo
Known for its green credentials, San Francisco already uses several recycling programs to divert almost two-thirds of its household garbage away from landfills. The city aims to divert all of its waste from landfills by 2020.
The poop-to-methane project is an extension of another bio-recycling program the city initiated ten years ago, when it began collecting food scraps from houses and restaurants and turning them into fertilizer for vineyards and organic farms.
Today 300 tons (272 metric tons) of food scraps are collected every day from more than 2,000 restaurants and tens of thousands of homes.
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