The commodities slump is nearly four years running, with devalued materials from weak demand and low oil costs taking their toll on recyclables markets. And this is happening while contamination continues to plague recycling streams. Some say the latter problem is exacerbated by single stream recycling, which broaches the question, has the blue bin passed its heyday?

Santa Monica, Calif., says no. In fact the city underwent a major overhaul two decades ago, converting from dual stream to single stream, and it has no intention of turning back.

Portland, Ore., on the other hand, rejected single stream from the start, and likely will never budge, according to their solid waste and recycling program manager.

It's emblematic of the debate that is playing out within the industry. Single stream’s proponents and opponents typically agree on a few points: it’s easier for residents, cheaper for haulers and harder on recyclers than dual stream systems. Beyond that, things get dicier. 

The plastics and glass challenge

Portland takes a fairly aggressive stand against mixed waste. The city has a dual stream program (though some would call it modified single stream). Households get one cart for paper, plastic and metal. But each household gets a separate bin for glass.

“Virtually all of Oregon collects glass separately and we see other cities beginning to question challenges of glass in single stream systems," says Bruce Walker, the city’s solid waste and recycling program manager. "Dual stream yields a more marketable product. You don’t have it break and cross contaminate paper and plastics. And there’s less wear and tear on equipment; glass is abrasive.” 

Portland’s glass recycling facility helps keep the material out of the stream, as does Oregon’s bottle bill—the first in the nation.

“I think it’s simple,” says Walker of their system. Though it’s not cheap, which can deter glass collections.

“Cities need to weigh costs and benefits and make their own decisions,” he says.

Even as some municipalities work through the glass challenge, MRFs tread rough terrain as they become inundated with more hard-to-handle materials. This includes rising volumes and types of plastic containers.

“Residents say it’s plastic and should go in the cart. Some is recyclable. But there are plastics that can pose huge sorting challenges,” says Walker.  

Santa Monica, Calif. is shooting for 95 percent diversion by 2030 and believes single stream has the city on its way to that goal. Currently the city's rate stands at 81.3 percent, with a 14 percent contamination rate, says Kim Braun, Santa Monica’s resource recovery and recycling manager.

(Braun will speak on a Waste360 Recycling Summit panel addressing the question “Has Single Stream Peaked?” on September 21. It will also feature Michelle Leonard, vice president, SCS Engineers and Bill Keegan, President, Dem-Con Cos.)

Santa Monica moved to single stream in the late 90s after converting its collection vehicles from rear loaders to automated side loaders.

Money and space were drivers

Prior to switching to single stream, Santa Monica residents had three bins: one for paper, cardboard and aluminum; one for plastics; and one for glass. But at 8 square miles and 100,000 residents, 75 percent of which live in multifamily structures, Santa Monica was crunched for space to place multiple containers.

“In the long run we save a lot of money. Before we would have had to send three trucks or continue to send the same guy in the same truck after emptying each load to avoid contaminating,” says Braun.

Now they pay for the blue bin, one truck and one driver per route.

“I get the fact that materials could be contaminated. I get that a lot of material is rejected because processors can‘t get rid of it. I also get that I just have to monitor closely,” says Braun, commenting sometimes people throw garbage into shared recycling containers when dumpsters fill, which she deals with by adding pickups and or increasing size and number of trash containers.

She believes some challenges of single stream will lift.

“As soon as oil goes back up processors are going to want material. That’s how it has worked before regardless of the issue of contamination. But for now, as managers of municipalities we shouldn’t say, guess what you can’t [put all recyclables in one bin] anymore.”

What about the burden on MRFs?

Braun believes in sharing the burden and profit in both good and bad times through a system where payments fluctuate depending on how commodities fare. But she says, she would never go back to three bins; it would require a major and costly overhaul.

“I would rather find a processor that can handle single stream.”

Whatever way municipalities go, almost all of them push for consumer education on how to recycle, visible signage and finding ways to curb contamination. Keeping streams clean and dealing with a rocky commodities market takes focus.