ICF of Florida

Some customers who grab coffee and donut probably don't even notice, but there's something different about a Dunkin' Donuts in St. Petersburg.

At first glance, the store on the corner of 4th Street and 76th Avenue North looks like many others. But if you ask Nancy Roberts, she'll tell you they have a favorite color.

"We do green in our store because our store is green," Roberts said.

They have cups made from recycled paper, bins to recycle them again and even green customers.

"I buy recycled materials, everything I use goes to the recycle bin," Nicole Yarber said. "I try to make sure to buy stuff with recycled material in it."

But what they do with used coffee grounds and filters is what people talk about most—they're put in a dumpster and eaten by 80,000 worms.

"I've actually had people come into the restaurant and ask me to grind coffee so they could feed the worms and see what it's all about," Robert Aziz said.

The worms eat the grounds, then the excrement is used as fertilizer. But the worms don't eat donuts, so what's left over goes to food banks.

Then there's the building itself.

"The building is made out of a system called ICF block, a foam form system which is filled with concrete," said Dan Lavender, construction manager for Dunkin' Donuts Florida.

That's a big energy saver.

"Well we estimate that our air conditioning bill is reduced by 40 percent by using this system," Lavender said.

You can't find a Dunkin' Donuts like this one anywhere else in the world-- of the 7,900 stores, it's the only green one.