Waste Watchers: Knoxville's Recycling

So what happens to all of those aluminum cans we drop off at recycling centers?

More Waste Watchers: Find out where our sewage and our garbage end up.

As anyone who has known me for, oh, 20 minutes, can attest, I really, really like to be right.

But not just kind of right, or probably right, which is why I've always felt a little funny about recycling aluminum cans. I do—I put my Coke Zero can in the cardboard box at Dean Hill Bridge Center every Thursday evening, and I sort any stray beer and soda cans that come into the house on board-game night from our artichoke heart and organic black bean "mixed metal" cans and then tote them to the City Recycling Center off Chapman Highway here in South Knoxville.

But I'm not feeling completely good about it, much less about leaving nag notes for whoever at work tosses their cans into the kitchen trash container with the coffee grounds. I'm not even sure I should shudder when I see the Burger King trash can stuffed with recyclable cans (don't ask why I am intimately familiar with this particular receptacle), or watch friends at a party find a trash can as they finish their tall PBRs. Because I'm not completely convinced anything good happens to the aluminum cans—I've seen too many collection bins that have, oh, 17 bimetal cat food cans and maybe an empty laundry detergent bottle in with the Bud and Coke empties (that can't be good), and I've never seen anyone actually pick up any cans. Which leaves me wondering: Do our half-hearted attempts to salvage some of these aluminum drink containers do any good to anybody, or is it all kind of farcical, designed to make us feel a little better?

One fine April morning, I set out to answer that question, beginning at Park Village off Cedar Bluff—it's a fenced lot, just the size of a suburban yard, and one of the busiest of the city's nine drop-off centers. Minutes after I topple my bright red Cherry 7-Up can into the proper half of the bin, the collection was over. No wonder I've never caught anyone at it! City contractor Waste Connections sends a truck by, and the driver wheels his giant vehicle right in and backs it up before you can say Jack Robinson, maneuvering it as deftly as if he were driving my little Toyota. The truck scoops the bin up, running it up a sort of trolley track on the bed. The driver jumps out of the cab, rock music blaring, shades in place, and checks to make sure the bin's locked on the truck. Then he jumps back in his seat, and he's off.

Next stop: RockTenn Recycling off Western, an 8.1 mile drive. This is where the cool part begins. Not the safety glasses and netted neon vest I'm required to put on, but the vast, chugging, sorting operation in progress; it somehow looks like the rock quarry where Fred Flintstone works. Everything is huge: The ceilings are at least 50 feet tall, the baler is at least a story tall, and the chutes and conveyor belts stretch for 40 yards or more. Vats and stacks of every imaginable recyclable dot the inside and outside the giant warehouse—shredded paper, crushed cans, huge squashed cubes of plastic. The faintest scent of stale beer and sour milk left in plastic jugs lingers in the air.

I'm touring with general manager Derek Senter. He's a likable sort with a sense of humor, a fondness for the expression, "It's pretty awesome," and an overt affection for the new technology that's been installed as part of a roughly $2 million upgrade. One of the upgrades is aimed at making it possible to retrieve glass from single-stream recycling. The single-stream idea is already possible in most of Knoxville through a private-pay system, and it should become more prevalent with the city's impending curbside pick-up that could be serving as many as 20,000 homes by later this year. "Our buyer sees commingled as the future of glass; it's not going to keep coming in all nicely sorted into green, brown and clear," Senter says. "On the plus side, with more people recycling in a single stream in their kitchens, the cans tend to be cleaner, and they don't tend to reek as much as they used to."

The Waste Connections truck is in the front lot with my can. The driver goes in and out twice, weighing the mixed metal and aluminum cans—which are much more valuable—separately. Then he's out of the equation, as the cans are dumped in a giant bunker. To my surprise, they're mixed with everything else I so carefully sift out before I head for the recycling center: Mounds and mounds of paper, plastic, and aluminum fill the space. A guy in a "CAT front-loader" drives around picking up giant swallows of mixed recycling and heaving them into a metering bin, keeping it full so the belt it feeds has a steady, even flow of recyclables. (This vehicle looks like an oversize Tonka truck bulldozer, but with what I just call "the Claw" on the front of it—a big, scary metal grabber with teeth.)

Inside, my can and its compatriots get sorted from the chafe first by human hands, with six pre-sorters pulling out cardboard, some large plastic, and trash as it speeds by. Then a "polishing screen" pushes lighter fiber up, up, and over the top of a dizzying array of items shaking their way up a jiggling metal screen about the size of two front doors. The heavier containers shake down and drop through a hole down to another belt, where workers pull out any cardboard or trash that's made it through. Next, the plastic is handled by a super gizmo—an optic sorter that can recognize the top-grade PET plastic at a molecular level and instruct one of 74 nozzles to "shoot" it with air as it passes, propelling it up and over to another belt where it's blown out into another bin.

But back to my little 7-Up can. It's barreling down in an "eddy current," in company with lots and lots of beer cans and a few Diet Coke cans, and more trash of all sorts—a plastic football, a Tang container, some spreadsheets that accidentally made it by. When the can reaches a wheel that would do any Spanish Inquisitor proud, it finally has its turn to be grouped. A magnet inside the wheel propels the aluminum cans upward (they're very into dramatically flinging select objects at this place), and they land in another bin.

Then it's all pretty straightforward: crushing the cans and baling them into giant squares that weigh 1,000-1,200 pounds apiece. Forty bales are loaded on each outgoing truck, but that's where Anheuser Busch or another buyer picks up the process—paying for the cans by the pound and taking them to a smelter somewhere else. There used to be a smelter some buyers used in Alcoa, but now they go further away.

Goodbye, little can!

In the course of the tour, I learned something I've been doing wrong with aluminum recycling. Pie pans and foil heat at a different temperature than aluminum cans, so they can't be recycled, at least not at RockTenn. Instead, a worker has to spot and remove them from the belt.

But I learned one thing that made me more than happy to continue my scolding, disappointment, and obsessive-compulsive retrieval of spare cans: Aluminum cans are the highest-priced commodity at the sorting plant, but they account for just 1 percent of what comes in there.

As if that wasn't enough good news, on the way out, Senter mentions that one time they got 12 pallets of hard-cover book rejects for recycling—and they were all written by Bill O'Reilly.