Allowing compostable plastic bags in a food scraps collection program can address the "yuck factor" and bring in more material, but be ready to sort them out, experts said.
"There's a trade-off," said Jack Macy of the San Francisco Department of the Environment. "You get more food if you allow certain compostable plastics, but then you have more handling at the facility."
Macy was one of several speakers participating in a webinar covering the use of compostable plastics in food scrap collection programs. The webinar was hosted by the US Composting Council's (USCC) Research & Education Foundation.
Macy, the senior coordinator of San Francisco's recycling program, talked about his city's work with Recology to manage an organics collection program, which started as a series of pilot projects in the 1990s. Compared with many other cities, his dense city of 850,000 sees a large percentage of food scraps – 20 percent – in its stream.
San Francisco's program allows households and businesses to place food scraps in plastic bags as long as they're clearly labeled "compostable" and have a logo indicating they're certified by the Biodegradable Products Institute, he said.
The bags have "been instrumental in helping us maximize our collection," he said.
Once the material reaches one of the two regional composting centers operated by Recology, compostable bags must be separated by hand from the stream destined to become certified organic compost; instead, they're sent to a separate, non-organic compost stream, he said.
Participants in the webinar discussed the challenges presented by "greenwashed" plastics, as well as confusion by consumers about which plastics are compostable.
Technology isn't available to automatically sort between compostable and non-compostable plastics, so workers must do it by hand, said Matt Cotton, who is the owner of Integrated Waste Management Consulting and works for the USCC.
"Really, to a great extent and for the last 25 years we've really tried to discourage any traditional plastics arriving at composting sites," he said. "That said, some of them do arrive."
Leslie Lukacs, principal of L2 Environmental, discussed how the use of compostable plastic food-service ware at events can increase diversion rates. But she emphasized just how big a problem greenwashing is, showing a photo of a non-compostable plastic cup with a green stripe across it and a box of forks labeled "biological."
Austin, Texas, meanwhile, is still learning how it wants to roll out a citywide food scraps collection program.
Jessica Kingpetcharat-Bittner, manager of strategic initiatives at municipal agency Austin Resource Recovery, discussed her city's organics pilot project collecting mixed yard debris and food scraps. The processors don't like accepting compostable bags because of the added processing time, she said.
In the first phase, the city used kraft bags, but food-service establishments and residents have indicated they want compostable plastic bags, Kingpetcharat-Bittner said.
"Everybody knows the 'yuck' factor," she said. "We heard from post-surveys from customers that they really wanted a compostable bag option that would help them manage the yuck factor."