With Curbside Composting, Food Waste Not a Total Loss
Wasting around 40 percent of all the food produced in the U.S. certainly has its drawbacks: It's not feeding people in need, it's expensive and it does a lot of environmental damage.
But across the country, cities, towns and companies are finding food waste doesn't have to be a total loss. In fact, it can be quite valuable – in making fertilizer, electricity or even fuel for cars, trucks and buses.
More than 180 U.S. cities and towns are trying to tap that value by offering curbside food scrap collection. They're asking residents to separate unwanted food from the rest of their trash and put it in a curbside compost bin. The idea is to stop sending food waste to the landfill where it generates harmful methane gas pollution and start turning it into something useful – like compost that people can use to enrich the soil.
However, while these curbside compost programs are better than landfilling, experts say they only address a fraction of the food waste problem.
Kicking Food Waste to the Curb
Portland, Ore., residents Jessie Hanna and Stephen Gardiner used to put some of their food scraps in a backyard compost bin. They would mix in some yard waste to make a nutrient-rich soil amendment for their garden.
Then, in 2011, the city of Portland launched a curbside compost program. Trash pickup was reduced from weekly to once every other week, and residents were encouraged to put all kinds of food scraps in the city's green yard waste bin – even things that couldn't go in a backyard compost bin.
"We could compost meat and dairy and bones and pizza boxes that still had cheese on them," Hanna said. "That was pretty impressive, I thought."
Gardiner and Hanna found it was easier to put all their food waste in the curbside bin and send it to a commercial composting facility. It freed up space in their yard and also reduced their trash loads. While the city offers trash pickup once every two weeks, they only pay for pickup once a month.
"While it's great in terms of reducing waste in a feel-good kind of way, it also saves us money," Gardiner said. "We spend less on trash because we are able to compost."
Separating their food waste means keeping an extra bin in the kitchen. Onion skins, potato peels and other inedible items go in a tupperware container they keep under the sink. Every few days, they empty it into the green bin in their driveway. The bin does get stinky, Hanna said, but it's easy to wash out.
"It's never going to smell good, but you know that going into it," Hanna said. "It's not your air freshener."
Slashing the Environmental Impacts of Trash
Dieter Eckels tracks what's in the trash for Cascadia Consulting Group. His company has picked through the garbage in cities across the U.S., and it consistently finds food waste makes up 20 to 30 percent of what's in the trash can.
"When you look at it in a pile, it's a pretty small piece of the pile because it's really dense compared to, say, a pile of styrofoam," he said. "But by weight the largest single piece of the garbage is food."
Since the city of Portland launched its curbside composting program, the amount of garbage it sends to the landfill is down 37 percent. According to Bruce Walker, the city's solid waste and recycling program manager, that also reduces the environmental footprint of the trash heap.
When food waste gets to the landfill, it's only a matter of time before it decomposes and releases methane, a greenhouse gas that's 25 times more potent than carbon dioxide.
"It's reducing methane production, but also making a useful product out of this material," Walker said.
Tapping the Value of Food Waste
Stephan Banchero, CEO of Cedar Grove, the company that composts food waste for the city of Seattle, Wash., says he sees compost as "the most local, renewable resource around." A lot of the compost his company makes gets sold to local farmers who then use it to make more food.
"I don't think a lot of people understand how closed loop of a system this is," he said. "Nothing is being shipped overseas. It's being used right here locally."
There are some challenges to making compost from curbside food scraps, though. When people fail to separate all the plastic from their food scraps – things like the stickers on fruit peels or plastic bags that contain rotting lettuce – it all comes to his facility and ends up in the final product. Cedar Grove had to add a second screening process to filter these pieces out before it can sell its compost.
Getting people to separate their food waste in the first place can also be difficult. To motivate its residents to put more food waste in the compost bin, the city of Seattle has proposed making curbside composting mandatory and fining residents a dollar every time they put too much food waste in the trash can.
While Portland's residential food scraps get composted, commercial food waste from restaurants and businesses goes a different direction. They're trucked to a methane digester that extracts gas from the food so it can be used to make electricity.
"It could also be used to make compressed natural gas to fuel trucks," Walker said. "There's different options for digesters and cities are exploring that across the country."
A variety of companies are testing out new ways of tapping the value of food waste: Turning industrial food waste into biogas to fuel city buses, fermenting food waste into ethanol for race cars, and blending food waste from grocery stores into liquid fertilizer, to name a few.
The Bigger Problem
But none of these options for recycling food waste justify wasting food in the first place, according to David Allaway, policy analyst for the Oregon Department of Environmental Quality. That's because most of the environmental impacts of food waste don't come from putting it in a landfill.
"Even though food in a landfill is a pretty bad thing, the impacts of producing the food in the first place is typically 10 to 30 times higher," Allaway said. "There's a tremendous amount of resources and pollution that come from the production of food."
Allaway says a quarter of all the fresh water withdrawals in the U.S. and as much as 5 percent of the country's greenhouse gas emissions come from producing food that never gets eaten.
"The food is being produced because somebody is buying it, and that somebody is all of us," he said. "It's households, it's restaurants, it's cafeterias and hospitals and convention centers and hotels. We have this system that creates inexpensive food. This low price encourages people to buy more than they're going to use. It has a low price, but environmentally it's not cheap."
Recycling food waste by turning it into compost or energy doesn't reduce the impacts of producing it in the first place, Allaway said.
"When you compost food waste, you're reducing the environmental impacts of food by a fraction," he said.
So, while composting is better than landfilling, he said, it would be much better not to waste food in the first place.
Cassandra Profita reports for EarthFix, a public media project focused on the environment.