Taking sides on single- or dual-stream recycling

Contamination issues and depressed markets for recyclables have some communities reconsidering the mix of materials they collect for recycling. Other communities are examining the methods they use to collect and process recyclables, believing that transitioning from single-stream to dual-stream collection will address their top-most contamination concerns.

The WasteExpo 2019 session titled Single Stream vs. Dual Stream pitted proponents of the two collection methods against one another. Louie Pellegrini, president of Peninsula Sanitary Service Inc. (PSSI), Stanford, California, and Willie Puz, director of public affairs and recycling for the Solid Waste Authority of Palm Beach County, Florida, shared the success they found in converting communities from single stream to dual stream, while Anne Germain, director of waste and recycling technology at the National Waste & Recycling Association, Arlington, Virginia, shared her perspective on the benefits that single-stream collection offers.  

Pellegrini said Northern California is home to 16 to 18 curbside collection systems that originated as dual-stream programs and remain that way. He shared his company’s experiences transitioning Milpitas, California, from single-stream collection to dual stream in 2018.

For the dual-stream programs it services, PSSI uses a 50/50 split cart to collect recyclables, and its collection vehicles have a 60/40 split.

“It’s very simple if you think about it,” he said. “Why mix it together? That is going to create contamination and broken glass.” Pellegrini said sorting is easier and the value of the commodities are higher when these two streams are collected and processed separately.

PSSI also provides single-stream collection to some communities, and he said the large 96-gallon carts with their “big lids” make it easy to place items into the carts that are not actually collected through the recycling program. He said pay-as-you-throw programs also worsen contamination when 96-gallon carts are used. While the company uses carts of a similar size to collect dual-stream recyclables, their smaller lids dissuade contamination. “It’s not easy for them to put in the stuff that shouldn’t be there, which adds to the contamination level.”

Pellegrini said contamination in the single-stream programs the company services is reaching 40 percent.

“That paper stream is clean,” he said of the dual-stream programs. “In some of our small operations, we’ve taken it directly off the collection vehicle and sent it to a paper house with no further sorting.” 

Pellegrini said processing the container stream also is simplified. “Your glass gets broken, but there are larger pieces that could be color sorted.” He adds, “Selling [glass] off a dual-stream collection, I truly believe you are always going to get a higher and better value.”

Regarding the glass produced through the company’s single-stream operation, he said it is “broken glass with a bunch of other contaminants in it, so we haven’t gotten the best value for the glass stream.”

In Milpitas, Pellegrini said the new collection vehicle accounted for 4 percent of the capital expenditures needed for the dual-stream conversion, which amounts to 4 cents per household over 10 years, which is the contract term. “The cart is your major expense,” he added, noting that the split cart was 33 percent more expensive than the traditional 96-gallon cart, or 17 cents per month per house over 10 years.  

Pellegrini said a 10 percent residual rate for dual-stream programs is “achievable,” adding that some communities are even lower than this, while the single-stream residual rate is nearing 25 percent in some of the communities PSSI serves. The reduced contamination translates to a potential savings of 47 cents per household as a result of the change in Milpitas. “On an economic basis, I think it pays for itself,” he said.

Puz shared the benefits of transitioning Lake Worth, Florida, which he described as a “city that went in the wrong direction” by implementing a single-stream program earlier in the decade, to dual-stream collection, or “what we feel is the right direction.”

Lake Worth, home to more than 38,000 residents, was approached by a hauler 11 years ago that offered the city $10 per ton for its recyclables if it transitioned to single-stream recycling. However, when the hauler approached the city to renew its contract in, the numbers were very different, Puz said. Now, the city was looking at paying $85 per ton, or $187,000 annually, to renew that contract. If the city opted to landfill the material instead, it would be looking at an annual cost of $92,400, he said, “plus the backlash from the residents” for discontinuing the recycling program.

The Palm Beach County Solid Waste Authority uses a two-bin program to separately collect paper and containers. The authority also has a recycling revenue share program where it splits 50 percent of the revenue it receives from selling recovered recyclables with the communities it serves.

The authority presented five proposals to Lake Worth, Puz said, that offered varying levels of financial liability for the city. Puz said city officials opted for a 50/50 revenue share split, with a 10.5 year pay off. Lake Worth also agreed to follow the authority’s webpage template to help its residents recycle right, providing consistent messaging whether residents visited the city or county site.

Puz said the authority helped the city with an outreach campaign to residents informing them that the recycling program would be changing. The campaign included bill inserts, press releases, the city e-newsletter, banner stands in libraries and city buildings and posts on Nextdoor. Additionally, nine sandwich board signs were placed throughout the city and free billboard ads were.

A number of paid initiatives also were used, including door hangers and video campaigns, he said. Social media influencers also helped to promote the change.  

The conversion went live Oct. 1, 2018.

“From day one, residents embraced the change, and we were very grateful for it,” Puz said.

The city’s recycling contamination rate declined from 20 percent in the single-stream program to the 5-7 percent range in the dual-stream program, he said. “That’s an incredible accomplishment there.”

NWRA’s Germain said, “I think Louie and Willie did a very good job of putting forth a very persuasive pitch on why dual-stream.” However, she suggested the increased education might have played a greater role in achieving the contamination reductions the cities saw than the change in collection method alone.

She mentioned the confusion that surrounds recycling, saying, “If we as recycling professionals get confused, how can we expect the public to understand?”

Germain said labels confuse the matter for consumers, noting the difference between the How2Recycle label, which provides specific details on how to recycle a product, versus the recycling symbol that appears on plastic packaging with the resin code, though that is not an indication of whether a product is recyclable. 

“Contamination is inversely related to quality,” she said, adding that the chief contaminants in the recycling stream—electronics and batteries, needles and sharps, plastic bags and diapers, for example—are the result of “wish cycling” and not whether a program is dual or single stream. “One of the things that we can take away right away is that education really is key.”

When single-stream recycling was first introduced, participation increased, Germain said. “And that was one of the things that everybody said” would happen. However, she attributed that increase to an increase in education surrounding the change. “Dual stream, if it had the same level of outreach when it was a mature program, participation might have increased,” Germain said. The same applies to conversions in the opposite direction, she added.

“If that same level of effort was done to a single-stream program that decided to remain single stream, would the material become just as clean?”

Germain said recycling education declined over the last 12 years or so, adding that education programs that remained in place focused on encouraging and increasing recycling. “That is what led to a lot of the wish cycling and the contamination that we are experiencing,” she said. “Recyclers have long been reluctant to discuss contamination because they didn’t want to discourage anything, therefore wish cycling really increased.”

A lack of feedback from the hauler further exacerbates this issue, Germain said.

A number of programs require mandatory participation, which she said leads to increased contamination, as do less frequent collection of recyclables, pay-as-you-throw programs and variable rates.

Germain said the recycling contamination rate in 2009 averaged 7 percent. That figure rose to 16 percent in 2014, she said, and to 25 percent in 2018. However, Germain noted that some single-stream programs have 8 to 12 percent contamination rates because they have continued education. “You can have low contamination rates with either program.”

She also cited potential safety concerns with dual-stream recycling, pointing the Palm Beach County program as an example. “We are trying to move the industry to just having a single driver and not having somebody outside the truck primarily because we are one of the top most dangerous industries in the country,” Germain said. The NWRA would like to see the industry value the health and safety of its employees over cost concerns, she added.

Issues also can arise for single-stream material recovery facilities (MRFs) that attempt to process dual-stream material. Germain said dual-stream material would have to be metered in with single-stream material so the throughput of the MRF is not affected.

Before communities retool their collection methods, they might want to re-evaluate their education efforts. If they can achieve similar results through education and avoid the capital expenses that accompany the dual-stream transition, it might be in their best interests.