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Intelligent robotic sorting cuts landfill waste, risk to human workers

Even in 'facility of the future,' plastic bags are still a problem

By Julia Tellman Local News Reporter

Editor’s Note: Diverted: Tracing the path of recycling in Whatcom County is a multipart series that follows waste from curbside to commodity market. Find previous stories here.

Much of Bellingham’s comingled recycling, the unsorted material collected by Sanitary Service Company in the newly introduced single tote, travels south in semitrailers to a state-of-the-art material recovery facility, or MRF, in Woodinville.

The Cascade Recycling Center, operated by the national corporation WM (formerly Waste Management), is called a “MRF of the future” after a major renovation to automate and refine its sorting abilities. Newest in the region, it’s outfitted with what WM education and outreach coordinator Logan Nelson calls “the bleeding edge” of recycling technology. 

A 2023 WM recycling facility overhaul incorporated volumetric scanning and optical sorting to improve efficiency and increase the amount of material diverted. (Julia Tellman/Cascadia Daily News)

The 2023 facility overhaul cost $40 million and incorporated intelligent sorting technology that eliminated much of the manual labor once common in recycling sorting facilities. MRF workers have much higher rates of nonfatal injury and illness than the general workforce. Sorting by hand in the loud, dusty work environment poses numerous hazards, including accidental needle sticks or glass cuts, the use of heavy machinery and fires caused by improper disposal of batteries. 

Now the MRF is staffed by 45 employees, most of whom simply monitor the system or perform maintenance. Only a few workers manually sort near the beginning of the operation, removing large cardboard boxes and obvious nonrecyclable items, such as couch cushions, from the stream.  

Only a few workers manually sort, removing large items from the recycling stream.  (Julia Tellman/Cascadia Daily News)

Apart from those workers, the machines are in charge — conveyor belts crisscross the 82,000-square-foot facility, which has an updated fire suppression system for those inevitable battery fires. Materials are separated automatically by shape, size, weight, dimensionality and material in a variety of ways. Magnets pull ferrous metals onto rotating wheels, glass is crushed and filtered out of the system, aluminum cans are shaken out of piles of paper, and a trommel (a huge rotating drum) separates two- and three-dimensional items. 

“This is pretty low-tech stuff, it’s just being creative,” Nelson said about the mechanical sorting systems.

The 16 optical sorting machines on the floor are where the real innovation is happening, he added, calling the system “the Swiss Army knife of recycling.”

Items fall onto accelerator belts and are spaced out before passing under a beam of bright light. Camera lenses observe the light waves that bounce off each object and read its “signature,” which determines its material makeup. Sixteen times a second, the computer targets jets of compressed air at the objects to shoot them over a divider wall in the proper direction. Optical sorting can even be used to determine different kinds of plastic, which have different resale values. One final pass through a sorter at the end of the line ensures that as many recyclables as possible are retained instead of being landfilled.


Camera lenses observe the light waves that bounce off each recycled object and read its “signature,” which determines its material makeup. (Julia Tellman/Cascadia Daily News)

Decreased ‘residuals’ to landfill

At Cascade Recycling Center, WM processes recycling from King, Snohomish, Skagit and Island counties, as well as a small portion of Whatcom’s recycling, delivered by Lautenbach Recycling

The facility currently receives between 525-575 tons of material daily — around 325 dump trucks coming in and out per day — with the capacity to handle another 100 tons. Twenty trucks a day leave the MRF with baled material to be sold for various uses. 

The Woodinville recycling facility currently receives between 525-575 tons of material a day. (Julia Tellman/Cascadia Daily News)

Before the facility renovation, WM was trucking between five to seven loads per day of “residuals,” i.e. nonrecyclable trash, to the landfill. Residuals could be anything from garden hoses to shoes to food-contaminated cardboard. Now, with more sophisticated sorting abilities, that number has dropped to one to three trucks of trash a day. 

“We’re incentivized to recycle as much as possible, in order to minimize our landfilling cost,” Nelson said. “You look around at this facility and it’s pretty hard to think, ‘We’re just loading up plastic and dumping it in the ocean.'” 

WM Communications Manager Patrick McCarthy listed some of the end markets in an email to CDN. Water bottles can be used for new carpet or fleece-type clothing; tin cans are recycled into rebar; aluminum cans and glass bottles are melted down to continue serving the same purpose; and some plastics can be made into rigid plastic products like buckets, laundry baskets and storage bins.

Between 2022 and 2023, WM increased the amount of plastic material recovered by 10%. 

“It’s also important to note that WM sends all plastic recyclables to end markets in North America,” McCarthy said. “That’s WM policy, in response to concerns about plastic in the environment.” 

A major issue at the facility is plastic bags and film, which invariably find their way into the recycling stream even though they are not accepted by single-stream curbside haulers. Product wrap, newspaper sleeves, produce bags and Ziplocs frequently get tangled in the sorting equipment, belts and drums at the MRF and can even force operations to temporarily shut down. Pulling bags or film out of machinery is a dangerous task. 

“There’s a maintenance cost and labor cost in the time it takes to deal with film and bags,” Nelson said. “We get it out but it’s a pain.” 

At Cascade Recycling Center, vacuum nozzles throughout the facility suck bags and film out of the recycling stream and send them speeding through pipes overhead at 60 mph, but still many bags make their way through the sorters. 

WM outreach coordinator Logan Nelson shows a tour group that strange things can end up in recycling bins. (Julia Tellman/Cascadia Daily News)

WM is currently baling those errant bags, in hopes of one day finding a market for them. The supply of recycled film and bags outstrips the demand, according to the national nonprofit The Recycling Partnership, but there may be more demand in the future. In 2022, WM acquired a controlling interest in Natura PCR, which produces resin pellets made from post-consumer plastic including film. Trex, a company that produces alternative decking materials, is one of the leading recyclers of plastic film but has high quality standards. 

(In Whatcom County, SSC accepts plastic film and bags at its drop-off center on 1001 Roeder Ave. in Bellingham.) 

Sharing the message

WM gave a facility tour on June 20 to a Whatcom County group that included industry representatives, county employees, business owners and the nonprofit Sustainable Connections. 

WM gave a facility tour to Whatcom County representatives in June.  (Julia Tellman/Cascadia Daily News)

Brandi Hutton, the assistant manager of Sustainable Connections’ Toward Zero Waste program, has toured four MRFs this year alone. She observed that each facility has a different workflow and somewhat different technologies driving processing. But in general, her takeaway has been that recycling is working. 

“Seeing it firsthand, seeing how passionate individuals are, and seeing how many bales and trucks a day are getting shipped out to businesses that are going to recycle these products, it’s wonderful to see,” she said.  

Around seven years ago, when China started banning the importation of some types of waste and set strict contamination limits on recyclable materials, recyclers scrambled to find domestic markets for all the materials they once sent overseas. 

“I think when Asia as a whole started rejecting us sending the bulk of our recycling there, so many people thought that it stopped and hadn’t picked back up,” Hutton said. “It was really nice to see that it’s happening, it’s happening efficiently.” 

McCarthy said that the demand for recycled materials has grown significantly over the past several years. The local market for recovered paper and paperboard in particular has increased thanks to an uptick in the use of recycled paper content and the growth in e-commerce. 

WM will offer a virtual tour of its MRF at noon on July 26. (Julia Tellman/Cascadia Daily News)

WM’s “Recycle Right” message to customers is to make sure recyclables are empty, clean and loose — that means no food items, no liquid and no plastic bags. As part of its outreach program, WM is offering a virtual tour of Cascade Recycling Center at noon on Friday, July 26. (Register at wmnorthwest.com.)

“What we do in our homes, at school and at work directly shapes the success of local recycling programs,” McCarthy said. “For a community, the foundation for a healthy recycling program is education.”

Hutton agreed: “I think that education really stands as our biggest pinch point.” 

Historically, Sustainable Connections has focused its outreach efforts on helping businesses cut down on how much waste they produce, but Hutton said the organization is pivoting to general education, with a social marketing campaign launching later this summer that will target regular contaminants in recycling. Next year’s focus will be on compostables, in tandem with the beginning of compulsory curbside organics collection in Bellingham.  

Right now every city, county and curbside collector has its own list of what’s recyclable locally, depending on facility capabilities, cost considerations and commodity markets. In Whatcom County, the Waste Wise portal provides local information on what’s recyclable.

“My biggest hope and dream is one coordinated list of recycled materials,” Hutton said. “That way, no matter where you went, you knew how to recycle, across Washington state.”

Future installments of Diverted will explore C&D (construction and demolition recycling) and commercial composting.

Julia Tellman writes about civic issues and anything else that happens to cross her desk; contact her at juliatellman@cascadiadaily.com.

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