Artist's Poo-For-Fuel Project Gets Messy

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A warning to listeners: Fecal matter plays a somewhat prominent role in this story.

The Park Spark Project at the Pacific Street dog park in Cambridgeport (courtesy photo)
The Park Spark Project at the Pacific Street dog park in Cambridgeport (courtesy photo)

Part of modern life means implicitly consenting to certain things. You flip a switch in your house, and coal gets dumped into a power plant hundreds of miles away. Well, that bothers Matthew Mazzotta.

Matthew is a 33-year-old Cambridge artist who has been working on a project to convert dog waste, of all things, into a modest amount of usable energy.

In the process, Matthew hopes to spark his fellow Cantabrigians to think a little more deeply about their energy, where it comes from and where it could come from. His concept has gained international attention. But execution has proven more difficult — and more messy — than he could have possibly imagined.

I FIRST MET MATTHEW TWO weeks ago, in the rain, down at the Pacific Street dog park in Cambridgeport, a little fenced-in gravel area where I take my dog Lucy sometimes. He introduced me to his Park Spark Project.

"We have two tanks here," he demonstrates. "One is the digester, which is anaerobic, which means no oxygen gets in there, and the other one is vented, which means oxygen can get in there. That's kinda like your septic tank."

A digester is basically a place where you put any kind of biodegradable waste — like old food or manure — and you collect the methane that comes off it. Methane is an extremely potent greenhouse gas, and if you burn it, you split it into less harmful carbon dioxide and water. Plus, you get some free energy.

"I sat in this park with my friend Clay, and I saw the garbage can full with all the dog waste, and I was just like you know, right there, people use that in other countries for cooking and all this stuff, and then it hit me, What's the potential of all this energy being wasted right now?"

Matthew figured he’d prime his digester with cow dung. And as his buddies Paul and Jegan tell me, that’s when things first got “out of hand.”

Matthew specializes in audacious feats of do-it-yourself engineering and projects that deal with themes like community and the environment. For example, a 15-person bicycle he built called a "busycle."

After that epiphany he had at the dog park, Matthew got a grant from his alma mater, MIT, as well as support from the Cambridge Arts Council, to build the world's first public methane digester run on dog poop.

I have a look inside the digester.

"If it was light, you could see right in there and see some cow dung," Matthew says.

Wait, cows? How did cows get in the dog park?

Well, here's the thing. You can't just gradually accumulate dog feces in a can and get a digester going. You have to foster a very specific type of methanagenic bacteria. So Matthew figured he'd prime his digester with cow dung. And as his buddies Paul and Jegan tell me, that's when things first got "out of hand."

They had to go down south to get some manure. And they had to mix the manure with water, but the water couldn't have any chlorine in it, so they had to fetch buckets and buckets of water from the Charles River.

"Cow manure is getting all over us in ways that we're not liking it," Matthew says. "At this point Jegan is so covered that I say, 'You can't get in this truck with your pants on.' So as I'm driving, he's in the back with his pants off."

At one point, five or six of the lids fly off the back off the truck. Right in the middle of Mass. Ave.
Paul jumps out and yells, 'Hey man, don't touch those! They're covered in s--t!'"

Matthew's buddies, Paul and Jegan, unload the tanks at the park. (courtesy photo)
Matthew's buddies, Paul and Jegan, unload the tanks at the park. (courtesy photo)

"And Jegan's in the back, with his hands in his lap, no pants on, and he goes, 'Man, this night's getting out of hand.'"

And to what end? I mean, what does one do with the combustible gasses emitted by about 400 gallons of fermenting Charles River water and dung? Well, on that day in the rain, Matthew tried to show me.

"It goes from the digester into a pipe that goes below the outlet tank, and it goes up this lamppost and into the lamp fixture. And so now I'm going to go into the lamp fixture and light it."

Out came a rickety wooden ladder he'd been hiding in the bushes next to the park.

"So, the City of Boston gave me this lamp fixture."

It's lovely. It's an old Beacon Hill gas lamp.

He tries several times to ignite the gas. No dice.

Three nights later, Matthew called me and said he was going to try again.

There's a new sign on display: "Sorry for the delay, currently we are waiting for the right population of microbes to flourish in the tank to make flammable gas."

Matthew tries to light it again.

"Nope. I've been experiencing this phenomenon with this system," Matthew says, disappointed. "Instead of gas being shot out like it should be, when I close the system, I think what happens is it pushes everything into the overflow tank, and then as the night cools, it actually sucks the flame into it, which is the opposite of what I want to have happen, so, not a success tonight."

At this point, I could see Matthew's characteristic good spirits flag a little. Trying to light this stupid light was bad enough, but the struggle was keeping him from getting at the real point of his project, which isn't so much about a lamp, as it is...

"Kind of a social intervention," he says. "What can we do with this flame that's in our neighborhoods being powered by dog waste? In India and China you know they use it to light spaces and cook. What are we gonna do with it in Cambridge?"

FIVE NIGHTS LATER, MATTHEW CONVENED a public meeting in an office space across from the park. The idea was to get people from the neighborhood to brainstorm ways to use this energy for something more than a lamp. Only four people showed up, including me and Matthew's friend, Jegan.

Matthew handed out paper and markers, everybody brainstormed some crazy ideas and read them aloud.

"...Um, dividing the light into tiny lights lights, uh, a connection to the Charles River, I don't know where that would go, outdoor huts for homeless..."

"...I actually, I like the idea of dentistry a lot, because..."

"Of what?"

"Dentistry. Like, if you could give somebody a root canal with the energy that's being produced here..."

Suffice it to say, a consensus was not reached.

We found ourselves back at the park one last time: Matthew and Paul and Jegan and me and Lucy, the dog. Matthew thinks it's going to work this time.

Lucy contributes something of her own. I walk over to the special doggie bag dispenser Matthew has mounted on the lamp and tear one off.

"These are biodegradable, these came from Italy," Matthew says. (They have to be, to work with this system.)

Having officially christened the dog-waste portion of the project, we stand back as Matthew climbs his ladder, flicks his lighter.

It lights.

"Yeah, you see this? But it's a blue light, not a white light," Matthew says.

"It's... it's on fire though," Paul says.

"It is on fire. This is way better than we've ever had it before."

Actually, there is one more problem.

There's a street light right next to it. Like, a really big, bright streetlight.

"You're right," Paul says, "I think it would be much more dramatic without a streetlight shining directly on it."

As I walk away, I see the boys holding up some lawn chairs they found in an effort to cast a shadow on the lamp long enough to get a photo. The phrase "out of hand," once again, seems apropos.

Post-script: Things are now looking a little brighter for Matthew Mazzotta. The flame in the lamp is getting bigger every day, and he's open to suggestions about what the community might do with that energy in the future. You can see the Park Spark Project at the Pacific Street dog park in Cambridgeport until Sept. 25.

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