From wool dryer balls to a company that builds affordable green homesfrom a high school greening project to a free collection program for stuff that's tricky to recycle.

Those are a few of the "green innovators" squaring off at the eighth annual Greenfest Philly this Sunday.

"We are really looking forward to getting out there in front of the people in Philadelphia and spreading the word about the fact that you can recycle a lot more than you think you can with TerraCycle," said company spokeswoman Stacey Krauss.

The Trenton-based company will be talking about its new Cigarette Waste Brigade and other efforts to slim down the nation's landfills.

Greenfest organizer Katie Edwards says the winning company will take home $750 and some exposure. The diversity of the companies participating is a plus.

"We really like these ideas because they run the gamut," said Edwards.

A panel of judges, Greenfest attendees as well as online voting will determine the winner. The Green Innovators will take the stage for a panel discussion at 12:30. One will be crowned champion at 4.

"Obviously, this is a friendly competition," said TerraCycle's Krauss. "I'm looking past that into ways that we can kind of lift each other up and work together to make real change."

Edwards — the special events director at the Clean Air Council, which organizes Greenfest — says the point of the annual gathering is to educate attendees on ways to live greener. The hope is to inspire action along the way.

"We want [attendees] to go around and talk to the innovators and see what they're doing," said Edward. "'Why did you start this? What gave you that idea? How did you get this off the ground?' [We want] to get other people thinking."

Organizers are expecting about 10,000 people to pass through Greenfest. It happens from 11 a.m. to 5 p.m. in Philadelphia's Headhouse Square.