Human Footprint - Sunday 9 PM ET/PT, April 13. This show will be on televisions everywhere

Human Footprint: Where Does All the Stuff Go?

Our human footprint doesn’t end after we buy and consume things; the final impact occurs when we discard items – and we Americans discard four-fifths of a ton of trash per person, per year.

Here are the numbers: Americans generated 251 million tons of trash in 2006, the most recent year for which the Environmental Protection Agency (EPA) has data. Our per capita trash disposal rate was 4.6 pounds per person, per day. Sixty-five percent came from residences, while 35 percent came from schools and commercial locations such as hospitals and businesses.

Where does it all end up? Fifty-five percent gets buried in landfills, 33 percent gets recycled, and 12.5 percent goes to incinerators.

Collecting and transporting trash and recyclables is a mammoth task. According to the National Solid Waste Management Association, the solid waste industry employs 368,000 people. They use 148,000 vehicles to move garbage to 1,754 landfills and 87 incinerators. They also pick up recyclables at curbside in 8,660 communities and take them to 545 materials recovery facilities for sorting. Solid waste is big business to the tune of about $47 billion in annual revenue.

After You Throw It Away
If your trash goes to a landfill it will end up sealed in the ground. It won’t decompose much, if at all, because air and water can’t get in. “Most landfills are more like mummifiers than composters,” wrote Elizabeth Royte in ‘Garbage Land.’

Landfills have some adverse environmental impacts. Despite careful engineering, they can leak liquids into the groundwater. Landfills also release one-fourth of all methane; landfill and wastewater treatment gases made up 2.3 percent of U.S. greenhouse gas emissions in 2005. At some landfills, gas-to-energy projects capture the gas to make electricity or to replace other fuels.

If your trash goes to an incinerator, it gets burned and turned into ash, which is used to make roads or parking lots, or is dumped in landfills. The burning also produces gases such as nitrogen oxides and sulfur dioxide (both cause smog and the latter causes acid rain), as well as trace amounts of toxics such as mercury compounds and dioxins.

Incinerators also create electricity. The 87 active incinerators (called waste-to-energy plants) generate 2,700 megawatts of power a year, which is enough electricity to power 2.3 million homes, but only amounts to 0.3 percent of U.S. power generation.

Pollution created by transporting waste to disposal areas also harms the environment. Trucks and trains used to move waste all create diesel exhaust, which contains nearly 40 toxic substances. Several organizations, including the EPA, have classified diesel exhaust as a probable or potential human carcinogen.

In Manhattan, for example, diesel trucks carry garbage 7.8 million miles every year, according to “Trash and the City,” a report by Environmental Defense. That’s the equivalent of circling the Earth 312 times.

New York City also ships its waste via truck and train as far away as Ohio and Virginia. Mel Peffers, an air quality project manager for Environmental Defense, explained: “Along that route all that pollution coming off of the diesel exhaust is very significant and it is the largest driver for our air cancer, our additional air cancer risk, and specifically the soot associated with diesel … is very bad.”

The Benefits of Recycling
Recycling avoids many of these impacts. When you recycle something, the item gets sorted and used to make similar items – aluminum cans, for example, contain about 41 percent recycled aluminum. It takes 95 percent less energy to make a can from recycled aluminum than from virgin bauxite ore.

By using recycled materials, the manufacturer creates fewer greenhouse gases. Recycling also reduces climate change emissions from incinerators and landfills. “Recycling is a win-win in terms of global warming pollution,” said Allen Hershkowitz, a senior scientist with the Natural Resources Defense Council and director of its national solid waste project.