Overall, compostable packaging breaks down successfully at composting facilities, an 18-month study from the Composting Consortium found.
The report, “Breaking It Down: The Realities of Compostable Packaging Disintegration in Composting Systems,” was the largest known field test of certified, food-contact compostable packaging conducted in North America, according to a press release. The study included over 23,000 units of certified food-contact compostable packaging, 31 different types of packaging materials in 10 large-scale industrial composting environments.
The study used two kinds of testing, mesh bag and dose, in which packaging was placed in a mesh bag and put into compost piles or was just mixed into the pile. The study also measured the disintegration at two points of the composting process and tracked composting parameter data, including pile temperature and moisture.
“This study analyzes the compatibility of certified compostable packaging with the diverse composting systems operating across the U.S. today, and highlights the nuanced approach needed to effectively recover this packaging type,” the report stated.
The study found that compostable plastic packaging and products broke down successfully: They had a 98% disintegration on average by surface area, which exceeds the industry threshold of 90% disintegration.
“There was a degree of variability in disintegration across the compostable plastic items in the mesh bag method,” the study noted. “Cups and cup lids consistently achieved high disintegration. Meanwhile, film items demonstrated higher variability in disintegration.”
Compostable fiber packaging and products had 83% disintegration on average by surface area, meeting industry thresholds for that material of 80% disintegration.
“Findings showed that certain operating conditions, like turning, agitation and consistent moisture levels above 50%, support increased disintegration of fiber packaging and products,” the press release noted.
The report also found that about 70% of composters who process food also accept and process some format of food-contact compostable packaging.
The data will be given to the Compostable Field Testing Program, which plans to launch an open-source database on the disintegration of compostable packaging.
“By making the results of our study publicly available, we seek to replace anecdotes with
data and opinions with insights, which can drive discussions, decisions and policymaking that will shape a more sustainable and circular future for composting and compostable packaging industries,” the report stated.
