Untangling Plastic Bag Snags

Jun 7, 2018, 21:08 PM
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By Megan Quinn

Mrf-PlasticsAt least once a day, while sorting tons of recyclables from about 400,000 of Phoenix’s single-family homes, the city’s two busy materials recovery facilities shudder to a halt—all because of the lowly plastic shopping bag. The bags, along with protective dry cleaning covers, overwrap from paper towels, and thin plastic bags that hold bread and newspapers, are a relentless pest for most MRFs. They get tangled in equipment and render it inoperable until a technician can cut it free. Any bags that pass through the sorting process can contaminate otherwise clean bales of paper and plastic. Plastic bags “are our No. 1 contaminant by occurrence,” says Lucas Mariacher, Phoenix’s zero waste coordinator. “The [bags] aren’t particularly heavy, but we get tons of them in our stream.”

The plastic bag problem isn’t new, but it’s especially problematic now that China has adopted new technical standards for contamination, which took effect March 1. Importers must meet new thresholds—no more than 0.5 percent prohibitives for paper and most other scrap—which are tough to meet when plastic bags and film cause so much contamination. Some MRFs are tackling the problem by rolling out educational campaigns, inviting the public into their facilities, and replacing equipment with newer models designed to reduce tangles.

A Formidable Contaminant

To most MRFs, plastic bags represent lost time and lost revenue. Each year, plastic bags and other prohibited items cost Phoenix about
$1 million in stalled equipment, equipment repairs, and processing fees, Mariacher says. Other MRFs around North America say they shoulder similar burdens: One MRF in Chicago estimates it spends $9,500 a month in labor just to pay workers to untangle bags from the equipment, according to the Chicago Tribune.

Belts, conveyors, drums, and beaters are all prime spots for bag snags, but some MRFs say disc screens or star screens are a particular nightmare. The screens have a series of parallel rotating shafts that catch wayward film plastic, which winds around the shaft so tightly that workers must shut down the equipment and climb on top of it to cut out the plastic. Workers at Waste Management (Houston) have to repeat this inconvenient, tedious, and potentially dangerous task “multiple times a day,” says spokesperson Dawn McCormick. This happens in every one of Waste Management’s 100 MRFs across the United States, she says. “It’s a safety and productivity issue and a difficult thing we’re asking people to do, so in some cases we actually increase their wage when they are part of a team that does that.”

Bags that don’t get caught in the machinery become an irritating contaminant, most often in the paper stream. Plastic bags and film are very lightweight and seem to have a mind of their own, says John Hansen, owner of Single Stream Recyclers (Sarasota, Fla.). They can sneak through sortation systems designed to separate more solid items like cans and newspaper. “There is no good way to sort it out. The [bags] are not quite two-dimensional, they’re not quite three-dimensional, and they float.”

China’s 0.5 percent prohibitives threshold is already hard to meet with a relatively clean stream, but excessive plastic bags and product overwraps make the job even harder, McCormick says. “We’re testing things like adding more labor, slowing down the line, and doing other things to increase quality, but that increases the cost, which ultimately gets passed to our customers,” she says.

Equipment Solutions

Despite the cost, labor is one solution MRFs deploy to remove bags before they get caught in moving parts or contaminate the materials. Hand sorters identify and grab the bags before they get too far into the sorting process, McCormick says. “Inbound, they try to pick the bags out, but there are too many in the stream to get them all,” she says. To get the bags that inevitably slip through workers’ fingers, some facilities have vacuum systems that pull film and bags into a bunker. Single Stream Recyclers also has an optical sorter on its fiber line to identify and eject any plastic that sneaks into the paper stream.

When the volume of bags and film is too great for those solutions, MRFs have begun upgrading equipment with screens specially designed to reduce bag snags, Hansen says. Single Stream Recyclers’ new MRF in Sarasota, which opened in March, has ballistic separators instead of star screens. The ballistic separators have paddles that move in an elliptical motion instead of the rotating, spinning shafts found in most star and disc screens. “It’s a little easier to clean, and bags don’t wrap around as easily,” he says.

Other companies are following suit. Waste Management installed anti-wrapping ONP screens from Van Dyk Recycling Solutions (Stamford, Conn.) at its MRF in Elkridge, Md., which Van Dyk says can reduce cleaning times by 90 percent. Waste Connections (McKinney, Texas) installed a similar screen in August 2017, which took maintenance time from two and a half hours to about 15 minutes a day, the company says. Before installing the anti-wrapping screen, the plant had three employees dedicated to cleaning the top screen deck during every break and lunch, which took those employees away from their quality control duties. Despite their efforts, the screen would become “100-percent blocked with film bags” a half hour after cleaning, the company says.

Outreach and Education

Though MRFs focus heavily on how to manage plastic bags once they enter their facility, they also must work with their communities to spread the word about the problems plastic bags cause, Hansen says. “We have to be proactive about what comes in, and education is a big part of that. If we don’t educate people, they keep throwing [bags] in there, and we keep picking [them] up. It’s the definition of insanity.”

Mariacher suspects most of Phoenix’s plastic bag and film contamination comes from residents who think the bags belong in the blue bin because they are made of plastic. “They don’t know why it’s so harmful,” he says. But MRF operators agree that simply telling residents the bags aren’t allowed isn’t enough. That’s why when Phoenix built its newest MRF in 2006, it decided to show them. “The North Gateway transfer station and MRF was designed with tours in mind,” Mariacher says. “We have a gallery with glass windows so you can see both the [processing equipment] and tipping floor. It provides an in-depth visual platform we had not had in the past.” The viewing platform can hold 120 people, which makes it an ideal field trip for local schools or community organizations to witness the recycling process (and its daily jams) up close, he says.

“Bringing people into the facility has been so helpful for us, but we know not every MRF is set up for people” to visit safely or without disrupting operations, Mariacher says. That’s why he also suggests that MRF operators or municipalities make time to visit local schools or meet with community groups. Phoenix recently held a recycling competition where local elementary, middle, and high schools competed against each other to collect as many plastic bags as possible, which were delivered to a local grocery store that provides collection bins for the material. “They’re learning at a young age that [bags] are not accepted in our blue bins, you can’t recycle them at the curb, but you can take plastic bags back to the grocery store and other retailers,” he says. The American Chemistry Council’s Plastic Bag Recycling initiative also provides a national list of bag drop-off locations, which is searchable by ZIP code at www.plasticfilmrecycling.org.

MRFs often find it helpful to partner with their municipality or state to amplify their message, McCormick adds. In her home state of Florida, Waste Management partners with the Florida Department of Environmental Protection and its “Rethink, Reset, Recycle” campaign, which offers printable banners, utility bill inserts, infographics, informational videos, and even social media pointers that Florida recyclers can use to spread a unified message about what can and cannot be recycled. Though a big focus of the campaign is explaining why bags are such a problem, it also highlights other common contaminants including garden hoses, holiday lights, and other “tanglers” like clothing.

Another strategy is to get your haulers involved, Hansen says. Single Stream Recycling flags recycling loads with excessive contamination and charges the hauler for it, hoping the hauler will go to the neighborhood to explain why items like dry cleaning bags can’t be recycled curbside. Yet he knows that conversation can be time-consuming and logistically hard to manage, and the money the MRF charges the hauler often gets passed on to the residents or the municipality that holds the contract. That’s why it’s in everyone’s best interest to work together on strong messaging about what can and cannot go in the blue bin, he says. “The municipalities bear some of the burden in this, and a lot of them are trying,” in his case either through the Florida DEP efforts or through other local messaging, he says.

But what happens when the messaging changes? West Coast recycling and waste management company Recology (San Francisco) had to grapple with this problem in October 2017, when it began allowing plastic bags and other film plastic in the recycling bin in San Francisco. Robert Reed, Recology’s spokesman, says the San Francisco MRF has done “extensive” education—posting flyers, sending information in customer newsletters, and doing other in-person outreach—to let residents know they must follow specific rules when recycling their bags and film to avoid causing clogs in the system. Residents must collect clean, dry plastic bags and film inside another plastic bag, preferably a clear one. Once the bag is about the size of a soccer ball, they tie off the top and drop it in their recycling bin. These directions are crucial, Reed says, because recycling workers stationed along the initial sort deck need to be able to spot the bundles and pull them off the line. “We need to be very clear that San Franciscans cannot put loose plastic bags and loose film plastic in their recycling bins,” he says.

Educational outreach has helped the collection process somewhat, but the plastic bag program is still relatively new and the company doesn’t yet have data on how big an impact the program has had on reducing loose bags and film. Day to day, Recology still has to deal with a few snags. Yet Reed says the MRF doesn’t collect very many bags to begin with because of San Francisco’s 10-year-old plastic bag ban, which prompted many businesses to start offering paper bags instead. About “80 percent of the material we collect in the blue bins is fiber—paper or cardboard,” he says.

Can You Sell It?

The expense of removing plastic bags from MRF material streams would be mitigated somewhat if MRFs could sell the film they recover, but MRFs that want to sell the material are finding few outlets for it. Since beginning plastic bag collection in 2017, Recology has been working on finding the right market. The “soccer ball” collection method isn’t just so workers can easily grab the bags—the outer plastic bag keeps the bags stuffed inside from getting contaminated with food and liquids, making the plastic cleaner and more attractive for sale, Reed says. But it’s still a tough sell, he adds. Typical markets for film plastic include manufacturers of synthetic lumber, railroad ties, and new plastic bags, but some reclaimers find they get better yields from film collected at grocery store drop-off points instead of buying the bags directly from a MRF. “Historically, there are not good markets for film plastics [from MRFs], so one of the big challenges in trying to recycle plastic bags is developing new markets and places to send them,” he says.

In Sarasota, Hansen of Single Stream Recyclers says the majority of bags and plastic film his company pulls off the line goes to the landfill because the material is rarely clean enough to sell. “Unfortunately, there aren’t any buyers on the market for what we have right now,” he says. The company’s MRF in Cocoa, Fla., which it has since sold to Waste Management, “collected a lot of film and bags, but I think we’ve sold [that material] only once or twice over the last three years.” The MRFs in Phoenix say they are in a similar boat. Trex Co. (Winchester, Va.), which makes composite plastic lumber from reclaimed film plastic, collects plastic bags from grocery store drop-offs throughout the city, Mariacher says—but the MRFs can’t compete with that stream’s quality and cleanliness. “Plastic bags and film from the [residential] recycling bin are just too contaminated,” he says.

Novolex (Hartsville, S.C.), a packaging manufacturer that uses recycled film plastic in its bags, is another company that prefers to source plastic film from drop-off centers instead of MRFs. About 90 percent of the scrap it purchases for bag manufacturing is postconsumer material collected through its own bag take-back program, which it operates through grocery store drop-offs. It’s more economical than getting the scrap from MRFs, says Phillip Rozenski, senior director of sustainability. Film from take-back programs has about an 85-percent yield, whereas scrap from a MRF has a less than 50-percent yield because of the contamination, he says. Novolex would consider buying from MRFs that have the technology to separate, clean, and bale the material, he adds.

Rozenski says he appreciates the role MRFs play in educational campaigns about plastic bags and film because they benefit both types of recyclers. Every time a MRF gets the word out that plastic bags don’t belong in the bin and instead directs them to a grocery store drop-off site, it provides clean material for Novolex and reduces its own jams and contamination headaches, he says. Novolex spreads the same message. “There’s an opportunity there to do it together,” he says.

Megan Quinn is reporter/writer for Scrap.

Plastic bags and film have long caused headaches for MRFs. They’re trying creative solutions such as MRF tours and educational campaigns to help tame bag contamination issues.

  • 2018
  • May_Jun

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