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Recycling

Recycling is only one part of solution to plastic waste, experts say

Product design and life-cycle assessment are also needed

by Cheryl Hogue
June 25, 2021

Photo shows a stack of used plastic bottles.
Credit: Shutterstock
The US Congress is considering a a bill that would suport research into plastic use reduction and recycling.

More plastic recycling and innovative approaches to it are a key part of, but not a complete solution to, solving plastic waste problems, experts told a US congressional panel June 24.

A sole focus on recycling could increase the proliferation of plastic and waste problems, Gregory Keoleian, a professor of sustainable systems at the University of Michigan, told the House of Representatives’ Science, Space, and Technology Subcommittee on Research and Technology.

Better product design with careful selection of materials that can be recycled must be integrated into efforts to reduce plastic waste, Keoleian said.

As an example of a waste conundrum that stems from the lack of systematic consideration, Keoleian noted that the manufacturing of automobiles involves dozens of types of plastic. These plastics wind up mixed—and hard to clean, separate, and recycle—when old cars get shredded to reclaim their steel, he said.

Life-cycle assessments of products can help producers avoid or limit the use of materials that can’t be reused, remanufactured, or recycled, he said. Such assessments also consider the greenhouse gas emissions associated with plastics production and disposal, Keoleian said, adding: “Plastics are carbon-intensive.”

Efforts to recycle plastic are “decades behind” the efficient production of virgin plastic from oil and natural gas, said Marc Hillmyer, a chemistry professor at the University of Minnesota and a sustainable polymer specialist. Yet to significantly reduce the growth of plastic waste build up in the environment, recycling has to compete on price, quality, and volume compared with production of virgin plastic, said Keefe Harrison, CEO of The Recycling Partnership, a nonprofit that works to improve recycling.

A key barrier to recycling in the US is contamination of plastics, which today comes in two major forms, Harrison said. One consists of labels, adhesives, and inks added to containers that render them difficult to recycle, she said, adding that research and development could address this problem.

The other contamination involves people wrapping up plastic containers in a plastic film bag, then offering it for recycling, she continued. Sorting centers trash these bundles—they take too much effort to separate and the plastic bag isn’t recyclable. Consumer education can help change this behavior, Harrison said.

Lawmakers on the subcommittee raised the possibility of biodegradable plastics. Hillmyer said many questions remain about how long and under what conditions a plastic item could biodegrade­—for instance, in a commercial composting facility with high heat and humidity or in a home compost heap. Researchers would have to determine whether such products would merely break down into environmentally persistent small pieces or get digested by microbes, he said. And they would have to consider whether labeling a plastic container as biodegradable would encourage people to leave it in the environment as litter.

Reps. Haley Stevens (D-MI), who chairs the subcommittee, and Anthony Gonzalez of Ohio, the top Republican on the panel, have introduced H.R. 2821, a bill that would support research into the reduction of plastic waste and the recycling of plastics. The American Chemical Society, which publishes C&EN, has endorsed that measure.

Keoleian told lawmakers that coordination of the federal government’s now-scattered research and development into plastic waste reduction and recycling would help scientists focus on the most significant challenges to this goal.

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