By Mike Augustin

Post-Bulletin, Rochester MN 

The recycling business is quickly becoming the poster child industry of the green movement, but have you ever wondered how it all works? How the items in your recycling bin make it from the end of your driveway to where they're reincarnated into something new?

In Rochester, your household probably follows one of two approaches to curbside recycling, depending on your waste hauler. In industry jargon, it's either "two sort" or "single stream."

The two-sort approach keeps all paper, boxboard and cardboard separate from plastic, cans and glass. The sorting process begins at the curb with the driver of the recycling truck tossing commodities into separate, truck-side bins.

The single-stream method, also called single sort, means all recyclables are placed together in one large rolling cart -- no sorting by customers or curbside trucks.

Julie Ketchum, the regional spokesperson for Waste Management, introduced single-stream recycling to the Rochester market this past fall. She says that for Waste Management, the next step is to load recyclables collected in Rochester into transfer trailers and haul them to a material reclamation facility (MRF) in Minneapolis.

The recyclables then pass two manual sorts, where workers separate cardboard and remove contaminates. Finally, a complex series of mechanical sorts using screens, magnets and air classifiers are used to separate recyclable materials.

Benefits of the single-stream system sited by Waste Management and others in the industry include higher recycling rates due to customer convenience, reduced neighborhood litter due to carts with lids, and reduced injuries and workers compensation claims as mechanical tipping replaces manual lifting into trucks. Larger carts allow every-other-week collection of recycling, cutting recycling trips down your street in half, significantly reducing their carbon footprint.

But is single stream all its cracked up to be? Critics raise concerns that cost-saving motives of streamlined, large volume operations might take precedence over providing consistently high-quality commodities to end markets that use recyclables to produce new goods.

Another point of contention is the residual rate: the quantity of unusable materials at the end of the sorting process. A study by the Minnesota Pollution Control Agency found rates among both single-stream and two-sort MRFs varies widely, with between two and 17 percent unusable residual.

So, do all those curbside recyclables actually complete the loop to make something new? Ninety-four percent of them do for Waste Management, the largest recycler in the state. They average a six percent residual, which includes contamination from the curb, plus any residual generated from the mechanical sorting process.

"With single sort, we're seeing a 15 to 20 percent increase in recyclables collected," Ketchum says. "That translates to about 10 pounds of additional material recycled per household per month."

Mike Augustin is a Rochester freelance writer.

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