The green economy is targeting a new color: brown. Each year the United States' 72 million dogs produce about 274 pounds of poo per pooch. Most of it ends up in landfills, where it oozes methane, a greenhouse gas. So eco-preneurs are offering biodegradable bags and compost services as well as new technologies that turn doggie dreck into energy. "Everybody's done it on a grandiose scale with 5,000-head cattle operations," says William Brinton, president of Woods End Laboratories, an environmental-testing lab. "[This is] the same technology, just simplified."
Lori Riegel of Tucson, Ariz., calls a local franchise called Doo Care to compost her greyhound and terrier-schnauzer droppings, and Mark Klaiman, co-owner of San Francisco's Pet Camp kennel, donates its dog waste to an off-site plant that converts it into electricity. (Eventually he hopes to use such energy to help fuel Pet Camp.) Others are trying to go green by flushing dog doo down the toilet. Sheryl Eisenberg, author of the Natural Resource Defense Council's "This Green Life" column, warns that leaving it in your yard can taint storm water and beaches. "The animals are part of our footprint," she says. Or paw print.