Additionally, while clean bales of flexible films are not yet a reality, equipment testing gave researchers hope high-quality bales of the material could be created in the future.
Consulting and research firm Resource Recycling Systems (RRS) recently released the results of a project exploring flexible packaging sortation at materials recovery facilities (MRFs). The research, conducted late last year and earlier this year, was done as part of the Materials Recovery for the Future project.
“With the completion of this research, we have established the first proof points towards our vision of being able to recycle flexible packaging,” Jeff Wooster, global sustainability director for Dow Packaging and Specialty Plastics, stated in a press release. Dow, which manufactures flexible film packaging, was one of several partners supporting the study.
Examples of flexible packaging include re-sealable food packages, pouches for soups and tuna, pet food bags and snack bags. The lightweight packaging choice is growing in popularity and is replacing more traditional types of packaging, such as rigid plastics and metal cans.
At the same time, no widespread recovery infrastructure has developed for flexible packaging, which often includes multiple layers of different materials and high levels of contamination.
Less paper bale contamination
In the project outlined in the recent report, researchers put flexible packing into mixes of recyclable materials and ran them through existing single-stream lines at MRFs. Those lines included screens and optical sorters. They conducted a baseline test at IMS Recycling in San Diego, followed by two MRF tests at Emterra Environmental facilities in Surrey, British Columbia and Regina, Saskatchewan.
In the baseline test, the final paper bale contained 3.3 percent flexible film contamination. But equipment testers were able to drive that number down to 0.6 percent by sending the materials through three optical sorters.
“The increased capture to the target product meant less flexible plastic packaging remaining in paper products, demonstrating the potential to reduce contamination of fiber bales if flexible plastic packaging is accepted in MRFs,” according to the report.
RRS also worked to optimize sortation equipment to test its ability to generate bales of flexible packaging.
In the first MRF test, researchers were able to create a bale with 28 percent flexible packaging. Most of the rest of the bale was made up of fiber, with a smaller amount of containers and assorted trash.
“One reason for the high contamination is that the optical sorting program was set to aggressively eject flexible plastic packaging, which brought fiber with it,” according to the report.
In the second test, they used multiple optical sorter passes. They also reduced the aggressiveness of the air jet firing area, which decreased the amount of fiber that was mistakenly ejected when the air jets targeted flexible packaging. The result was a bale with 46 percent flexible packaging, which RRS described as an “encouraging trend.”
“Many factors go into accounting for the reduction of fiber and increase of flexible plastic packaging, but the main factor was the modified optical sorting programming,” according to the report.
More research needed
RRS noted that further testing needs to be conducted before MRF operators and communities can consider accepting flexible packaging in their programs.
“Additional equipment testing to determine the costs and feasibility of required MRF upgrades, secondary processing and end market uses are critical to success,” Susan Graff, RRS principal and director of the Materials Recovery for the Future project, stated in a press release.
The Materials Recovery for the Future project is managed by The Foundation for Chemistry Research and Initiatives at the American Chemistry Council (ACC). Project partners include a number of consumer brand owners, retailers and packaging producers, as well as the following recycling industry groups: Association of Plastic Recyclers (APR), the Flexible Packaging Association, SPI: The Plastics Industry Trade Association (SPI) and the ACC.