What Happens to San Francisco's Recycling Once It Leaves the Curb?

10 min
A San Francisco Recology worker loads a bale of steel onto a truck where it'll be taken to McMinnville, Oregon, and turned into rebar. (Adam Grossberg/KQED)

Take a trip to Recology's Recycle Central, where San Francisco's waste is sorted and sent off for processing. This week on Bay Curious, we answer a question from Noe Valley resident Charlie Spiegel, who wondered where his recycling ends up.


harlie Spiegel is one of those people obsessed with getting recycling right.

"Like the peanut butter canister. If I throw this into the recycling -- this plastic thing that’s got peanut butter in it -- I have no idea what they do with it," he says, as he stands in the kitchen of his Noe Valley home.

He's pulling empty glass and plastic containers out of his dishwasher.


"Do you really wash these things?" I ask.

"Oh yeah, yeah," he says. "And then they come out melted."

Charlie has a lot of questions when it comes to recycling. Like what happens to stuff that can't be recycled that gets mixed up in the blue bins? Does he need to continue washing his plastics and jars? And what do those numbers on the bottom of his plastics mean?

Is Rinsing Recyclables Necessary?

The answers to all of Charlie’s questions were at Recology’s recycling center at Pier 96 near Hunters Point.

Inside the 200,000-square-foot warehouse, I meet Robert Reed, a project manager for Recology. He takes me to an open room called the tipping floor, where the recycling trucks first dump their contents after they leave your neighborhood.

Plastic water bottles, cardboard Amazon boxes, plastic bags and soup containers are corralled by tractors into colossal 30-foot mountains.

Six hundred tons of material come through the tipping floor each day, says Robert. That's equivalent to the weight of 38 Muni buses.

I bring up Charlie's first question: Do people need to rinse their recyclables?

He says a half-full jar of peanut butter would be too much, but their equipment is prepared to handle some residue.

But Recology does ask people to rinse out their plastics because it can pose a problem for paper products in single-stream recycling. If the food residue gets onto paper in your bin, it could make that paper non-recyclable.

How The Recycling Is Sorted

We leave the tipping floor, and follow the recyclables as they are scooped onto conveyor belts moving up toward a second floor.

Ayanna Banks is hand-sorting the material as it comes down the conveyer belt.

"I got here at 3:45 a.m.," she says. "It’s a hard shift because you gotta get used to waking up."

It’s dusty and loud at the plant -- so loud, you can’t hear a person 5 feet away from you.

Ayanna Banks has seen some pretty unusual stuff come through the line -- like car bumpers and a bank safe. (Adam Grossberg/KQED)

Fortunately, Ayanna has her headphones and there's one type of music that keeps her going -- gospel.

"That’s mostly what I listen to in the morning, keep my spirits up," laughs Ayanna, who says she likes to sing along, too.

Ayanna removes aluminum and cardboard from the paper, and separates out the trash, which is tossed into a chute for the landfill.

Paper goes straight to a high-density bailer, and plastics head toward one of the coolest machines in the whole warehouse -- an optical sorter.

Some parts of the recycling process are done by hand. (Adam Grossberg/KQED)

"You can see how it hits certain items with a puff of air," says Robert.

The machine works like a human eyeball, visually sorting the plastics by color and type. As the plastics approach the end of the conveyor belt, the machine shoots puffs of air at each item to direct it toward a bin of similar plastics.

Then they’re baled and sent to Central California, where they'll be turned into new products, like new recycling bins or water bottles.

And What About Those Numbers?

Charlie's final question was about those hard-to-decode numbers on the bottom of most plastics. Robert says those matter at other recycling plants, but not here in San Francisco. Recology can process any hard plastics it receives.

... Even if they're melted.

Reporting Back to Charlie

When I returned to Charlie’s house, I opened my laptop and played a video we took of the recycling process.

"Wow, labor intensive, my God they’re picking out stuff as they go ... wow," he says.

I asked if it's what he imagined.

"It’s amazing the volumes they’re going through," says Charlie. "And it’s amazing to me how labor intensive it is, 'cuz I just had no idea."

When I told him that food residue isn’t an issue, he was elated.

He can finally stop melting his plastic jars in the dishwasher.

An earlier version of this story said Recology users did not need to rinse out plastic recyclables. Recology has since updated its guidelines to ask users to rinse food residue from plastics to avoid contaminating paper recyclables.

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Wall of aluminum_star
An eddy-current separator repels aluminum cans off the line. They are then baled and sent to foundries in Tennessee. (Adam Grossberg/KQED)