A recent paper from a major plastics group finds there are both pros and cons to the “all in one bin” recycling collection and processing approach.

“There are key tradeoffs that that need to be analyzed as part of assessing mixed-waste processing,” the report, commissioned by the Plastics Division of the American Chemistry Council (ACC), concludes. “The technology promises to deliver more volume of recycled materials but potentially with a lower unit value for some materials because of contamination.”

Research for the report was conducted by Gershman, Brickner & Bratton (GBB).

The mixed-waste processing approach, which has been challenged by the the Institute of Scrap Recycling Industries and The Recycling Partnership, among others, forgoes residential source-separation of recyclables and uses mixed-waste processing facilities to extract recyclables and organics directly from municipal solid waste.

Mixed-waste processing has been in the spotlight recently, with a $45 million facility planned in Indianapolis and talk of a similar venture ongoing in Houston. A mixed-waste processing facility opened in Montgomery, Ala. last year. Such operations are sometimes called dirty MRFs.

“The goal of diverting more materials from the waste stream to higher uses compels us to explore all options,” Craig Cookson, director of sustainability and recycling for ACC’s Plastics Division, said in a press release announcing the study’s release. “As the waste stream continues to evolve, we must consider new strategies and innovations that could help us to meet these challenges.”

The GBB study, which can be read in its entirety here, suggests modern, “highly automated” mixed-waste processing could be capable of unlocking higher overall diversion rates than some single-stream programs. The quality of the recyclables recovered from MSW, however, remains a question.

“Until there is better publicly available data or testimonials from buyers of the materials, it will remain a challenge to evaluate newer [mixed-waste facilities],” the report cautions.

Study authors completed a waste characterization study for Fort Worth, Texas and estimated the City could push its diversion rate, currently at 19 percent under a single-stream program, to as high as 46 percent under a mixed-waste processing system that also diverts organics.

According to the characterization study, 28 percent of overall MSW currently makes it into Fort Worth recycling bins. Of that total, 67 percent ends up being recovered at a single-stream MRF, resulting in an estimated 19 percent recovery rate. No organics are recovered.

Under a mixed-waste system, GBB found, theoretically 100 percent of Fort Worth’s MSW would reach a modernized mixed-waste processing center. The study suggests a 70 percent recovery rate for organics under that system and an overall diversion rate of 46 percent for the municipality. “It should be noted that these numbers are from an equipment manufacturer with recent experience with these modern [mixed-waste processing] facilities,” the report notes.

The study also determined that if the city’s current single-stream program were paired with a mixed-waste facility to process trash, the recovery rate could jump to 54 percent.