Is Designing for Biodegradability a Solution to Managing Plastics Waste?

08 Jun 2022
Closing the Loop on Plastic Waste

About 50% of total plastics produced per year are used in disposable, short life, non-durable packaging and single-use products. Ninety percent of this plastics packaging and are carbon-carbon backbone, hydrocarbon plastics like polyethylene, and polypropylene. Used in thin or flexible film forms or with food, paper, and disposable product packaging, they are difficult to recover and clean from the MSW stream for recycling. In fact, the latest EPA’s MSW data analysis shows that recycling of non-durable plastics as percent of generation is only 2.4% and that of thermoplastic elastomers (rubber) is negligible. These carbon-carbon backbone plastics are non-biodegradable, persistent, and accumulate in the natural environment like the oceans. They fragment and break down into smaller and smaller particles, like microplastics and cause negative impacts as is being extensively reported in literature, press and e-media [The National Academies of Sciences, Engineering, and Medicine. 2021. Reckoning with the U.S. Role in Global Ocean Plastic Waste. Washington, DC: The National Academies Press. https://doi.org/10.17226/26132].

Re-designing carbon-carbon backbone polymer plastics at the molecular level to provide for certified and verifiable biodegradable and industrial compostable plastics is environmentally responsible. However, it must be ensured that after use, the compostable plastics along with food, paper, and biodegradable organic waste is treated at a managed industrial composting facility.  Managed industrial composting is necessary to divert food and biodegradable organic waste from landfills or open dumps to composting for reducing GWP impacts. The EPA WARM model estimates that recovery of 1.84 million tons of MSW biodegradable organic wastes through composting results in 1.7 million tons of CO2 equivalent of GHG emissions reduction. Complete biodegradability under composting conditions must be validated using ASTM/ISO International Standards and certified by certification organizations like the BPI (North America).

Unfortunately, there is much misunderstanding and misleading product claims about biodegradability and compostability in the marketplace. We will review the science around biodegradability and compostability and learn to identify unqualified, as well as misleading biodegradability claims. This @EnvSciTech article reports necessary requirements for assessing and reporting plastic biodegradation.

https://pubs.acs.org/doi/10.1021/acs.est.9b04513 .


Ramani Narayan, Distinguished Professor - Michigan State University