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The power of crap

The city of San Francisco wants to turn the ~6.000 tons of dog waste each year into energy. Yes, 6.000 tons of crap!

SAN FRANCISCO, California (AP) -- City officials are hoping to harness the power of dog waste in this dog-friendly city where animal feces make up nearly 4 percent of residential waste.

San Franciscans already recycle more than 60 percent of their garbage, but officials hope to turn into energy the 6,500 tons (5,897 metric tons) of dog waste a year -- nearly as much as disposable diapers, according to the city.
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The droppings will be tossed into a contraption called a methane digester, which is basically a tank in which bacteria feed on feces for weeks to create methane gas.
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Methane digesters are nothing new. The technology was introduced in Europe about 20 years ago, and more than 600 farm-based digesters are in operation there. Nine are in use on California dairy farms, and chicken and hog farms elsewhere in the United States also use them.

Via Lone Star Times