The two-day event is wrapping up at the Phoenix Convention Center.
Teams of people were challenged to create a prototype for an app to help the city tackle its waste problem.
"How to recycle, when to recycle, how to compose, and help us achieve our 40% diversion rate goal by 2020," said Lisa Faison with the City of Phoenix.
The Phoenix Innovation Games were announced last month during a "State of the City" address.
The winning team will get the chance to publish their mobile app.