From Arlo Guthrie, who wrote a seven-minute song about taking out the garbage, to Shel Silverstein’s Sarah Sylvia Cynthia Stout, who drowned in her own garbage, our society has long struggled with the excesses of its own existence. Today, Americans hold the title of biggest trash producers in the world, at 6.5 pounds per person, per day. This problem is perhaps no more evident than in Phoenix, the fastest-growing city in the country.

In 2008, Phoenix was named the least sustainable city in the nation in Andrew Ross’s book Bird on Fire. Everyone in Phoenix really hated being called that. So when Greg Stanton became mayor later that year, he decided to focus on sustainability. (Stanton has since become a congressman, taking the seat left vacant by now-senator Kyrsten Sinema.) Water was one big piece of the sustainability puzzle, but garbage was the other. The challenge Stanton faced was reducing the amount of garbage Phoenix sent to the landfill without changing laws or imposing fines, both of which would have been impossible to get passed in the middle of a red state. The city would have to rely solely on changing human behavior. It was a tall order.

In the last 30 years, Phoenix has gone from a population of 900,000 to the fifth largest metropolis in the nation, with 1.6 million residents. An average of 100 people moves to Phoenix every day. And that growth is likely to continue—the population is expected to double in the next decade—as people flood in from other cities that have become too expensive, too congested, and too difficult for middle-class Americans to survive in. But new residents don’t just bring a moving van and a down payment on a single-level house with a cactus in the front yard. They also bring their trash.

Phoenix is home to five closed landfills that don’t include modern fire-damping technology, at least one of which is at risk of spontaneously combusting. They also leach toxic chemicals into the surrounding land and water, and one was declared a Superfund site. The land can’t be built on or farmed; it’s all geographic dead zones. The old landfills are markers of failures on the part of previous city governments, not only from an environmental standpoint, but in anticipating how fast and how far Phoenix would grow, and just how much garbage Phoenicians would produce.

The city’s new landfill, opened in 2006, is as high-tech as a hole in the ground can be, with liners to protect the water table, a GPS-based scheme that dictates where and how garbage gets deposited, and tubing that siphons out and burns off the methane that garbage produces as it decomposes. At 2,654 acres in area and 120 feet deep, the landfill should last the city at least another 60 years. But it’s also 60 miles outside city limits and requires long-haul trucks, making 100 to 125 trips a day, to transport all of Phoenix’s garbage. It isn’t hard to see a future where Phoenix—and other cities—start to run out of space. One estimate projects that remaining landfill space for the entire United States is likely to last only another 62 years. As big and empty as the Sonoran Desert is, there are only so many times you can dig a giant hole and fill it to the brim with used diapers and yard waste.

The bigger cities get, the more garbage they generate, and the harder it is to figure out what to do with all of it. Increasing what’s known as the diversion rate—the percentage of items that previously would have been flung in the trash but that could be recycled or composted—is an obvious first step. Phoenix officials were well aware, and perhaps a little jealous, of the diversion rates of other western states. San Francisco diverts 80% of its trash from the landfill, leading the nation and causing much competitive angst in Phoenix. (“We’re never going to be San Francisco,” Stanton tells me.) Seattle diverts nearly 60%. Both are well above the national average of 34%. And Phoenix? “Our diversion rate was shocking,” Stanton says. When he took office, it was 16%.

Read the rest of Hana Schank’s article at Fast Company