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It stinks and it's a hazard to walkers everywhere, but it turns out dog poop has a bright side.

Dog poop is lighting a lantern at a Cambridge dog park as part of a monthslong project that its creator, artist Matthew Mazzotta, hopes will get people thinking about not wasting waste.

The "Park Spark" poop converter is actually two steel, 500-gallon oil tanks painted a golden yellow, connected by diagonal black piping and attached to an old gaslight-style street lantern at the Pacific Street Park.

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. 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. The park is small but has proven busy enough to ensure a steady supply of fuel.

Dog owner Lindsey Leason, a 29-year-old Harvard student, said she was all for seeing poop in a new light as she watched her two dogs play at the park.

"Since I have to pick up dog poop a lot, I think I'd rather have it be useful," Leason said.

The project was funded by a $4,000 grant from Council of the Arts at the Massachusetts Institute of Technology, where Mazzotta earned a master's degree in visual studies last year.

The 33-year-old Mazzotta, who is not a dog owner, got the idea after he visited the park with a friend in 2009. Mazzotta had recently traveled to India and saw people there using poop in so-called "methane digesters" to cook food. As he watched the park's trash can fill with bags of poop, he remarked to his friend, "In other countries, they use that."

A similar idea to use dog poop for power was floated in San Francisco about four years ago. But that idea fizzled in the city's bureaucracy and over concerns about safety, said environmental scientist Will Brinton, who worked with Mazzotta on Park Spark and was consulted in the San Francisco project.

Cambridge Fire Chief Gerry Reardon had his own questions about "Park Spark," including whether vandalism or poor design could cause the tank's insides to spill out and how the methane would be safely contained and vented. But Park Spark's sturdy build and safety features persuaded the fire department to give its approval, he said.

"We try to stay progressive here," Reardon said.

Mazzotta's project brings welcome visual distraction to the park, which is bordered by a rutted street, a weed-filled lot and the beaten-down backsides of a couple of buildings. Dog owner Louisa Solano, 68, said she loves Park Spark, though she thought it was "just a wonderful piece of sculpture, you know, modern art" when she first saw it.

The dog-poop converter's colors, symmetry and clean lines are intentional, but Mazzotta said his greater artistic purpose is to get people thinking differently about what's around them, including seeing waste as a resource and how to best use the free power it produces.

The practical benefits of the exhibit aren't lost on Mazzotta.

Burning the methane, which is 30 times more potent as a greenhouse gas than carbon dioxide, helps the environment, he said. And with dogs dropping tons of poop in cities everywhere, he thinks the idea of using its untapped power has broad appeal.

Brinton, president of Woods End Laboratories in Maine, which specializes in biogas energy development, said biogas from waste is a potentially major and accessible energy source, and a novel project like Mazzotta's can highlight that.

Mazzotta said right now he's not planning to start a dog poop energy business but is instead focusing on the ideas behind Park Spark, which will be dismantled at month's end. To him, the dog poop device helps fill a need for clean energy and better waste disposal, and all people need to do to fuel it is look around.
And be careful where they step.