As companies struggle to deal with the challenge of single-use packaging, compostable options are becoming more common, and consumers might consider it greenwashing if they knew that the packaging won’t ever actually be composted. The system, though, is beginning to change, including new innovations in materials. “These are solvable problems, not inherent problems,” says Rhodes Yepsen, executive director of the nonprofit Biodegradable Products Institute. If the system can be fixed—just like the broken recycling system needs to be fixed—it can be one piece of solving the bigger problem of growing trash. It’s not the only solution. Yepsen says that it makes sense to start by reducing packaging and prioritizing reusable products, and then design whatever’s left to be recyclable or compostable depending on the application. But compostable packaging makes particular sense for food; if both food and food packaging can be composted together, it could also help keep more food out of landfills, where it’s a major source of methane, a potent greenhouse gas.
Composting speeds up the natural process of decay of organic matter—like a half-eaten apple—through systems that create the right conditions for waste-eating microorganisms. In some cases, that’s as simple as a pile of food and yard waste that someone manually turns over in a backyard. The mix of heat, nutrients, and oxygen has to be right for the process to work well; compost bins and barrels make everything hotter, which speeds up the transformation of waste into rich, dark compost that can be used in a garden as fertilizer. Some units are even designed to work inside a kitchen.
In a home composter or backyard pile, fruit and vegetables can break down easily. But a backyard bin likely won’t get hot enough to break down compostable plastic, like a bioplastic takeout box or fork made from PLA (polylactic acid), a material produced from corn, sugarcane, or other plants. It needs the right combination of heat, temperature, and time—something that’s likely to happen only in an industrial composting facility, and even then only in some cases. Frederik Wurm, a chemist at the Max Planck Institute for Polymer Research, has called PLA straws “a perfect example of greenwashing,” since if they end up in the ocean, they won’t biodegrade.
Most municipal composting centers were originally designed to take yard waste like leaves and branches, not food. Even now, of the 4,700 facilities that take green waste, only 3% take food. San Francisco was one city that was early to adopt the idea, piloting food waste collection in 1996 and launching that citywide in 2002. (Seattle followed in 2004, and eventually many other cities did too; Boston is one of the latest, with a pilot beginning this year.) In 2009, San Francisco became the first city in the U.S. to make recycling food scraps mandatory, sending truckloads of food waste to a sprawling facility in California’s Central Valley, where it’s ground up and placed in huge, aerated piles. As microorganisms chew through the food, the piles heat up to as hot as 170 degrees. After a month, the material is spread out in another area, where it’s turned by a machine daily. After a total of 90 to 130 days, it’s ready to be screened and sold to farmers as compost. Recology, the company that runs the facility, says that the demand for the product is strong, particularly as California embraces spreading compost on farms as a way to help soil suck up carbon from the air to fight climate change.