Say what you will about Wal-Mart's tendency to crowd out mom-and-pop stores, it's hard to begrudge the company for its sustainability efforts. In the video below, we see that Wal-Mart's deli pizza boxes are part of a closed-loop cycle that uses retailer's boxes to make new ones, saving 40 million gallons of water and 8,600 tons of solid waste.
Wal-Mart's pizza box effort is just a small part of the company's sustainability initiatives. The big box giant is also working on a sustainability index that will rate and help the company choose suppliers based on greenhouse gas emissions, waste reduction targets, and water use. So suppliers that develop closed-loop projects will theoretically get more business from Wal-Mart.
For more info on Wal-Mart's greening, check out these videos from the company's recent Sustainability Milestone Meeting.