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Single Stream: What Works and What Doesn’t

Some regions report contamination rates as low as under 2 percent, and there appears to be common denominators among success stories.

Single stream recycling systems struggle with high contamination rates. As this system makes it easier to dispose of waste, more material ends up in bins than belongs in them, with contamination rates climbing as high as 30 to 40 percent in some regions, reports Susan Collins, executive director of the Container Recycling Institute.

Yet there is a huge disparity in these program’s numbers. Some regions report contamination rates as low as under 2 percent, and there appears to be common denominators among success stories. They include aggressive education and enforcement initiatives. And they typically include a comprehensive collection model extending far beyond picking up bins at the curb.

Springfield, Mass., is pushing hard to manage contamination while holding onto its single-stream system. The city is especially focused on enforcement as the state and industry increase expectations.  Massachusetts has a goal of 30 percent waste reduction by 2020. And facilities are tightening screws, demanding better quality as they weather a tough commodities market.

“MRFs are going through truckloads with a fine-tooth comb. If they find a pizza box, they can reject the whole load. We have to pick it up and take it to the incinerator at our landfill,” says Chris Cignoli public works director for Springfield.

“So we in turn stepped up enforcement with residents.”

Public Works routinely inspects barrels before picking them up. Workers put stickers on those containing prohibited materials, noting what needs to come out before haulers return.

This approach has cut contamination cases from 300 to 500 homes per day to 15 to 20. That’s among the 5,000 homes that the city services.

“When people realized they would get stuck with recycling for an extra two weeks they wanted to make sure they did it right,” says Cignoli, adding workers don’t just leave stickers, then drive away. They ring door bells and talk to people.

A multipronged communication system

Residents call the 311 system with questions. They learn how to recycle on a Facebook page, at a city website, and from flyers.

Neighborhood association groups, citywide, reinforce the message.

Other disposal vehicles

Springfield has separate yard waste pick-ups. Several times a year it provides a drop off point for hazardous wastes like greases, oils, paints and insecticides. Neighborhood groups sponsor an electronic drop off, and a company hauls these materials at no charge.

The programs come with a cost, largely extracted from the general fund. But it’s been worth it. Unlike in some towns that transfer their full cost for similar programs to residents, people do not improperly discard to avoid fees.

And the city avoids another large expense.

“It costs us $5,000 or more whenever there is a potentially serious flagged contamination issue. We have to isolate that load. We bring in consultants who go through the trash, identify the source and analyze it.”

The other side

Container Recycling Institute is not sold on single stream. Collins thinks diversion figures are typically higher than reported, pointing out that most studies rely on MRF’s residue rates, without consideration of additional post-MRF losses.

“A few years ago, Waste Management and other large haulers were generally saying that residual rates … were in the range of 10 percent. ... More recently Waste Management has said the average contamination rate for all of their facilities is 16 percent,” she says.

Houston has a contamination rate of about 26 percent, which Melanie Scruggs, program director for the Texas Campaign for the Environment, believes is for several reasons. For one, the city just expanded its curbside single-stream program to all neighborhoods in 2015, which has come with a learning curve, though Houston is working on a long-term plan.

Other challenges, she says, are limited education and mixed messaging when a One-Bin-For-All system was under consideration. Residents tended to think they could toss almost anything in the bin.

“We need consistent, targeted and diverse education and outreach,” says Scruggs.

As critical to ensuring residents know what, when and where to recycle is ensuring service providers meet to discuss what is working and the top two or three contaminants in the recycling stream, says Brenda Pulley, vice president of Recycling for Keep America Beautiful (KAB).

“Then communication can be targeted to better inform residents. Finally, consider not calling it “single-stream.” 

A KAB survey found only 11 percent of respondents indicated that the term meant that all recyclables could be included in the cart. But 77 percent thought “mixed recyclables” could go in one cart.

Meanwhile, as Springfield continues to fine tune single-stream operations, it is hitting milestones set by the state, which has earned it grants, says Cignoli. “That’s more we can invest to put other initiatives in place.”

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