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Public Radio's Environmental News Magazine (follow us on Google News)

The Scoop on A Unique Dog Waste Digester

Air Date: Week of

Methane and its makers. (Matthew Mazzotta)

A conceptual artist in Cambridge Massachusetts has come up with a novel way to curb canine waste while illuminating a large and growing problem. Host Bruce Gellerman tells the tale.



GELLERMAN: This is a tale with a happy ending…


SANTOS: Gio, come here puppy. Come on puppy, let’s go. Good boy! Good boy, Gio.

GELLERMAN: Once upon a time there was a man, and his best friend…

SANTOS: I’m Jay Santos and I live in the neighborhood. My dog Gio and I come here probably once or twice a day just to have fun and use the park.


GELLERMAN: Lots of dogs use this small corner park in Cambridge Massachusetts. It’s designed for dogs.

Gio and his best friend Jay Santos. Business is picking up. (Andre Gellerman)


GELLERMAN: There’s a chain link fence surrounding a field of gravel, where Gio, a sleek pharaoh hound, and his new friend, Sadie, a curbstone setter, can run and take care of business. For Gio’s owner Jay Santos, business is picking up.

SANTOS: I have a bag in my hand. I will be making a deposit. (Laughs).

GELLERMAN: Ordinarily, Santos would dump the bag into a garbage can, and city workers would haul the contents to a landfill. But since August dog owners at this park have been dumping their pet waste into a work of art called the Park Spark Project.

SANTOS: It’s form and function. I think it’s fun. We put our dog poop into it everyday, and it powers the light. What’s better than that? (Laughs).

Methane and its makers. (Matthew Mazzotta)

GELLERMAN: The art installation is a device that converts pooch waste into gas that powers an antique street lamp, shedding light on a common problem: how to curb canine carbon.

MAZZOTTA: Well my name is Matthew Mazzotta, and I’m a conceptual artist and I live here in Boston and I produced this Park Spark Project. Owning a dog is sometimes not the most environmentally sound thing you can do. I guess this is one way of reducing that footprint.

GELLERMAN: Or carbon paw print, as the case may be. It’s estimated there are nearly 80 million dogs in the United States. That’s a lot of climate changing waste, going to waste, in landfills. Last year, Matt Mazzotta traveled to India where he saw methane digesters used on farms. When he came back home, the light bulb went on over his head

MAZZOTTA: That garbage can used to be full all the time. That’s where I got the idea. It used to be totally full a year ago. I thought to myself, we should be using that…

Making a deposit into the methane digester. (Matthew Mazzotta)

GELLERMAN: Show me how it works…


GELLERMAN: At the edge of the park are two bright yellow metal tanks, and the old fashioned street light.

MAZZOTTA: So this is a digester, it’s a passive system, there’s no electricity, there’s no anything involved. The technology all lies in the fact that it’s anaerobic, which means, what you’re putting in there, you’re depriving it of oxygen.

So, here you have inlet pipe, and when a dog does it’s business, you pick it up, and you throw it in here, in one of these biodegradable bags, it goes inside and sinks to the bottom. And, in that environment, the microbes that are already in the waste, they start the breathe out methane, the same way we breathe out carbon dioxide, they breathe out methane. The dog waste goes in, and then there’s a little stirrer here that just agitates it.


MAZZOTTA: So it just turns like that. This is an old… I wanted some old looking handles, so I went to an antique store and I got this thing. And it kind of mixes this up a bit. It’s not the most essential thing, but it makes it a little bit more efficient.

GELLERMAN: How long does it take for the average bag to turn into a light?

MAZZOTTA: Well, the whole thing is that the bag has to biodegrade first before the dog poop can become usable. I started on cow manure, so I had to wait about a week and a half. And, actually had a scientist come down and he tested it. He says, ‘you know, you’re a little bit low on your pH, put in two boxes of baking soda.’ So then that actually cleared it up, and now the gas is burning nice and white.

GELLERMAN: So, you’ve had nothing else since then?

MAZZOTTA: No, and that’s why I think it’s so magical. I think that’s why I was interested in it. It’s a passive system and it just uses one technology- just close off the oxygen. So you’re using dog waste and water, and nothing else.

GELLERMAN: How much light will a daily dose of doo do?

Conceptual Artist Matthew Mazzotta and his latest creation. (Bruce Gellerman)

MAZZOTTA: So, the digester, the amount of light you’ll get is how big it’s scaled. This particular one I scaled it, I think on the rather small side for the amount of waste that’s coming in here. What I’ve been doing is just burning it all night. Turn it on at 7:30, and then turn it off in the morning when I wake up. But if you scale them a little bit bigger, and if there is more dog waste, this thing could run 24 hours a day, which is the idea, I think. That’s where I think it gets the most exciting-- this free energy source.

GELLERMAN: Not only is it free, but it burns free. I mean, it’s a carbon-recycling project.

MAZZOTTA: Yeah, I think, so there’s three, I think, three layers of awesomeness with this project. The first one is that you’re greening the park, you’re collecting this methane, which is one of the most potent greenhouse gasses. It’s like 70 times worse than carbon dioxide; this is reducing that by burning it. The second is a free energy source. And, then, the third layer is— what are we going to do with this? And I think that’s an exciting moment. What do we do with this free energy inside the city? I’m trying to collect ideas, so we can either turn it into a popcorn machine, or, something the community actually would want, and participate in.


GELLERMAN: What’s interesting is that it wasn’t an engineer that did this.


GELLERMAN: It was an artist.

MAZZOTTA: Well, I think that there’s a breed of artists that are these interdisciplinary, or trans-disciplinary, artists. They go into other disciplines. Say this technology has already been used, in biology in physics, but I think the artist’s role is to bring it to this new context to make this social role, or something more environmental. I think that’s the role of an artist that I’m in.

GELLERMAN: So, it’s art in context. It’s the context that makes the art.

MAZZOTTA: Yep, yep. It’s where you’re presenting this information. So, scientists might present it in journals, and have all kinds of mathematics involved. I’m taking it and presenting it to a park.

GELLERMAN: Do you have a dog?

MAZZOTTA: I don’t. That’s funny, right? I’ve met a lot of dogs through this, though.


GELLERMAN: Conceptual artist Matthew Mazzotta. The lights will go out on his Park Spark Project later this month…but his dog power methane digester has generated a lot of interest from as far as Bogota, Colombia, a small town in Italy, and Hungary. You can check out photos of our happy tale at L-O-E dot org.




Park Spark Project


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