Much skepticism surrounds mixed waste processing as a way method of recycling municipal solid waste. During Wastecon 2016, Aug. 22-24 at the Indiana Convention Center in Indianapolis, results of a mixed waste processing study conducted by Kansas City, Missouri-based Burns & McDonnell for the American Forest & Paper Association (AF&PA;), Washington, were shared.

Brian Hawkinson, AF&PA; executive director, explained the methodology behind the study. The “Mixed Waste Processing Economic and Policy Study,” published in September 2015, laid out four different recycling scenarios based on 250,000 household and 325,000 tons of material generated.

The scenarios, he said, included:

• Scenario 1 - A community with only a single - stream recycling program. The refuse container is collected by a second collection vehicle and hauled to a disposal location.
  
• Scenario 2 – A community with a single - stream program that adds a mixed waste processing facility to increase diversion. There are two collection vehicles that pass by each home: one for single - stream recyclables and one for mixed waste.
  Scenario 3 – A community that goes with a “one bin” system where are materials collected at the curb are taken to a mixed waste facility. There is no single - stream collection or processing for Scenario 3.
  
• Scenario 4 – Similar to Scenario 3 except that the mixed waste facility produces a refuse - derived fuel (RDF) from non - recyclable paper and plastics.
  

While Hawkinson noted, “Every situation is unique,” he said, “Single stream recovers more recyclables.”

He shared the following table from the study:

He noted, mixed waste processing recovers more metals and plastics than single stream, but recovers less paper.

He also said, mixed waste processing requires a greater capital investment.

“The economics favor single stream recycling as communities’ recycling rates increase,” said Hawkinson. He added that high performing single stream with a mixed waste system can recover the most recyclables.

“Mixed waste processing added to an already successful single stream system presents an option to achieve higher recyclables,” he said. He also noted that contamination from mixed waste processing is a major issue for the paper industry, particularly in the use of food packaging and other consumer items.

While some attendees questioned the methodology and results of the study, Hawkinson did note that results may vary based on the community and specific program.

Wastecon 2016, an annual conference hosted by the Solid Waste Association of North America was Aug. 22-25 in Indianapolis.