How do recycling centers separate materials? What are the steps in the recycling process? Learn the answers to your burning questions about recycling as we dive behind the scenes at a recycling facility.
Every other Monday, I wheel a 64-gallon jumbled mess of milk jugs, shredded paper, and refried bean cans to the curb — then righteously rub my hands together, knowing I’ve done my part to save the planet. An A+ performance. I know the contents of my bin will magically be reborn as cardboard boxes, maintenance-free park benches, and rebar to build new cities. But after trailing my bin to a recycling facility, I learn that my performance is, at best, a D. I’m with Bill Keegan, president of Dem-Con Companies, a third-generation family-owned waste and recycling management firm serving Minneapolis-St. Paul since the 1960s. We’re joined by Jennifer Potter, a community outreach coordinator.
Dem-Con welcomes thousands of visitors every year. The company has an interactive trailer it hauls to schools and festivals, along with virtual reality glasses that allow kids and adults to virtually step into the recycling process. Its goals are to help build a culture that recycles naturally and automatically, and to trigger a feeling of unease when people don’t recycle.
Behind the Scenes
Keegan, Potter, and I don blaze-yellow vests, hard hats, and safety glasses and head into the facility.
We climb 30 steps to a platform overlooking the tipping floor, where collection trucks disgorge mound after mound of mixed recyclables. Keegan shouts over the growl of trucks and machinery, “People recycle twice as much stuff with commingled or single-stream recycling like this [where all recyclables are collected in a single container] than when sorting their own stuff into bins.”
Dem-Con processes more than 50,000 pounds of commingled recyclables per hour; of that, 8 to 10 percent is garbage that should’ve been trashed, Potter says. “People figure if something goes into the trash, there’s zero chance it’ll be recycled. It’s called ‘wish-cycling.'” But those errant items wind up contaminating other materials and jamming machinery, and can be downright deadly. According to Keegan, “When in doubt, throw it out.”
Every few minutes, a steel-wheeled front-end loader takes a bite out of the 25-foot-high mountain of recycling and dumps it into a hopper. The hopper shakes the material onto rollers that spread the material evenly onto a wide conveyor belt. Bagged recycling needs to be ripped open by hand. When handlers don’t have time to do that, the entire caboodle is diverted into the trash stream. Plus, the bags clog machinery and aren’t recyclable at the plant.
Five trillion plastic bags are produced worldwide each year; only 1 percent are recycled. The average working life of a single-use plastic bag is 12 minutes; tests show it can take 100 years or longer for one to decompose. It’s easy to get lost in the maze of recycling statistics. About a thimbleful of petroleum is needed to create one plastic bag, but getting a paper bag from forest to store requires four times that amount of oil. And because cotton farming is so pesticide and irrigation intensive, you need to reuse a cloth bag 173 times for it to pay off. The “green” choice is shockingly hard to find.
The Human Element
Keegan, Potter, and I follow the 4-foot-wide conveyor belt as it travels uphill to a sorting cabin where six quick-fisted workers perform recycling triage. They pluck out oversized, dangerous, and unrecyclable items. The sorting process is 80 percent mechanical and 20 percent human, but literally every item that passes through the plant has human eyes cast on it.
I peek into the tub of rejects and find lamp bases, shattered lightbulbs, and old faucets. Keegan shouts above the roar, “If there was an inventor’s competition for the worst thing to be recycled, it would be the diaper — not one part recyclable.”
Potter says, “Sharps, syringes, and medical wastes are a constant problem. Everyone along the line has a pull cord and can stop the line — and it stops the whole line — to safely remove things.”
The team at Dem-Con is eternally vigilant, looking out for lithium-ion batteries, which are used in everything from vape pens to cellphones to cordless drills. Last year, one of Dem-Con’s transfer stations burned to the ground because of a single crushed lithium battery. It’s not unusual for a dozen fires a year to break out in the plant we’re touring. As we move on, a bag of shredded paper gets caught in a roller and explodes like a confetti cannon. Thousands of shreds rain down on people, equipment, and recyclables. My office shredder and I plead guilty. A massive conveyor belt moves to a series of spinning disks that launch cardboard panels and flattened boxes into a massive bin; everything else falls through. The plant is designed to separate two-dimensional materials (primarily cardboard and paper) from three-dimensional items (primarily containers). Because balled-up paper behaves like a 3D container, it’s more difficult to sort. Likewise, a flat milk carton behaves like a 2D object, making it more difficult to sort. Potter says it’s best to keep containers roughly in their original form.
Containers go through a machine that smashes the glass bottles. Those shards are sent to a company that removes contaminants and uses an optical scanner to sort the pieces by color. The shards are reborn as bottles, abrasives, or reflective beads for road paints and tapes. Everything else continues down the line. “The only glass containers people should recycle are those that originally held food or beverages,” Potter explains. “Mirrors, window glass, and bakeware have a different composition and melting temperature, and contaminate the truly recyclable glass.”
We enter an area where conveyor belts crisscross like a Los Angeles freeway. The materials pass over another series of disks that pull loose paper up and out of the stream and let everything else — mostly cans and plastic containers at this point–roll downhill to the container line. Keegan explains how a few years ago, mixed paper and junk mail bales sold for $70 a ton and could contain 2 percent contaminants. Then, the primary importer of plastics and paper, China, upped its standard to 0.5 percent contaminants and eventually stopped importing recyclable materials altogether, choosing to focus instead on recycling its own refuse. The U.S. market tanked. “Recycling has no environmental or economic benefit if you don’t have an end market for it,” Keegan says.
We continue zigzagging along a series of ramps and walkways, pausing at a magnetic drum that hurls my refried bean and tuna cans over an imaginary goal post into another bunker.
We follow the main line to a 6-foot-long optical scanner that blasts light onto each plastic item zinging by. The information is fed to a computer that determines each container’s composition in milliseconds. The data are sent to a series of air jets that blast No. 1 plastic bottles into the appropriate bin.
Then, we enter an enclosed room, where Potter introduces me to an artificial intelligence robotic sorter — a frenetic tentacle that snatches and sorts milk cartons, juice boxes, and No. 2 translucent plastic containers with the accuracy of a lizard tongue zapping flies out of midair.
Farther into the room, a dozen workers stand hip to hip before a relentless conveyor belt, further hand-sorting No. 2 and No. 5 plastic containers. (The numbers help recycling plants sort containers.) Containers with stuff stuck to the inside are tossed into the trash. Spending 10 seconds scraping peanut butter from the inside of a jar at home helps on multiple fronts. Potter explains, “The optical scanners can ‘read’ and sort the container more easily, and food doesn’t contaminate the pure plastics. It can make the difference between a jar being resurrected as a lawn chair or spending its life in a landfill.”
A Mixed Bag of Returns
On we march, past the aluminum can sorter, where an electrical current hurtles the cans through the air. Aluminum cans can be infinitely recycled, and they bring in $1,400 a ton. Recycling a ton — 75,000 cans — can save enough electricity to power an average home for a decade.
We follow a branch line carrying loose paper and junk mail. At the far end of the building, we see massive compacting machines creating car-sized bales of material. “The market value of recycled materials is a mixed bag,” Keegan says. “Aluminum is absolutely valuable, but it’s offset by the paper and glass that bring little, or may even have negative value.” Once sorted, the market value of mixed recycling might be $35 per ton today — a steep dip from the $140 it brought 10 years ago. But when you subtract processing costs — for hauling, sorting, and shipping — the price per ton can look pretty dismal. One solution is instituting extended producer responsibility laws, where companies that produce or use plastic and other containers pitch in on the cost of recycling programs, as they’ve done in Canada and Europe.
We’re getting better. In 1960, Americans recycled 10 percent of their waste; today, we recycle 35 percent. My home state of Minnesota, along with other states and cities, has set an ambitious target to compost or recycle 75 percent of waste by 2030; San Francisco is already there.
Alabama recycles about 9 percent of its trash, one of the lowest rates in the nation. Most of us sit halfway between Alabama and San Francisco with our recycling habits — and the beauty of recycling is that each person, household, and community can choose to use greater knowledge to improve their recycling efficiency, and even keep items out of the recycling stream altogether by reducing or reusing first.
The 5 Worst Things to Throw in the Recycling Bin
- Lithium-ion batteries can explode and catch fire when broken or crushed by machinery. Solution: Visit Call2Recycle and punch in your ZIP code to find a battery drop-off center near you.
- Shredded paper can contaminate entire batches of glass and other materials; it can’t be recycled at all centers. Solution: Compost it, or take paper to local shredding events.
- Plastic bags, films, and tarps wrap around belts and rollers, stopping entire production lines. Solution: Deposit bags in drop-off boxes located at chain store entrances. Visit Plastic Film Recycling for exact locations.
- Hoses, wire, and extension cords tangle machinery and can be a danger for workers to remove. Solution: Repair broken hoses and extension cords; otherwise, trash them.
- Sharp objects and syringes pose health hazards for recycling workers. Solution: Visit Safe Needle Disposal to learn about your state’s guidelines for disposal.
Spike Carlsen is an editor, author, and carpenter with several decades of woodworking experience. This is an excerpt from his newest book, A Walk Around the Block (Harper One), available now.
