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Recycling industry works to cut contamination

Mar 4, 2018

Jose Herrera stands in front of bales of mixed paper that are ready to be shipped to a buyer. Herrera is the plant manager at the Waste Management residential recycling sorting facility in Denver.
Credit Elizabeth Stewart-Severy / Aspen Public Radio

Before the first of the year, most of the recycling collected in the Roaring Fork Valley—and across the country—ultimately found its way to China. But China is no longer accepting items like paper and plastic from abroad. So what happens to your empty cans, bottles and boxes after you toss them in the bin?

Single-stream recycling is designed to be simple: Everything into the same recycling bin, which you then set out on the curb, or take to the local drop-off center.

Waste Management picks up your bottles, cans, paper and cardboard and combines it with the yogurt containers, milk jugs and empty boxes from across the valley, then loads it onto a semi-truck to Denver to be sorted, packaged and sent out to be re-purposed.

This dump-it-all-in-one-spot system is based around a key, human desire.  

“I mean, single-stream was a convenience," said Jose Herrera, the plant manager at the Denver facility where Waste Management sorts residential recycling. "And now that is kind of creating some other issues that we probably didn’t see 10 years ago.”

I followed a semi-truck full of recyclables into the facility and met Herrera for a tour.

He made me put on a hard hat and handed me a neon yellow vest and safety goggles. As we stepped carefully along the metal gangway, he explained I needed to keep three points of contact at all times — two feet and at least one hand on a railing.

The building is three stories tall, with heavy machinery working on all levels, up to 35 feet in the air. It is dirty and loud and the steps are treacherously steep.

Recyclable material rumbles along conveyors and through sorting machines at a Waste Management facility in Denver.
Credit Elizabeth Stewart-Severy / Aspen Public Radio

When a truck drops off a load of recyclables, all those bottles, cans, papers and plastics are dumped onto a conveyor belt. It rumbles through a Rube Goldberg maze of machines, conveyors and bins.

A sorted bin of milk jugs waits to be packaged and sent out.
Credit Elizabeth Stewart-Severy / Aspen Public Radio

“Our goal is to process over 30 tons an hour,” Herrera said.

That is to make tidy, sorted stacks of cardboard, paper, milk jugs and aluminum cans, and send them off to be re-purposed. The conveyor belts and machines toss materials into separate bins, all the aluminum cans in one spot, the newspaper in another and so forth.

Brent Bell heads up the recycling division of Waste Management. He explained that much of this used to then move by truck, train and ship to China.

"Waste Management, our Recycle America division, is actually ranked number seven in terms of the largest exporter out of the United States,” Bell said.

But there are a few materials that can immediately be recycled locally.

Glass, for example, is sorted out, crushed into small pieces and loaded onto trucks that travel just miles down the highway to Momentum Recycling in Broomfield, which turns your old bottles into new ones.

And Bell said aluminum cans are a recycling success story, too.  

“Within 60 days or 30 days, they have a quick turnaround that could be a new can again.”

The sorting is a mechanical process, based on weight and size and some fancy optical machines that work in a particular order: Cardboard, paper, newspaper, plastics, tin cans, aluminum cans and more plastics. Herrera calls the rest "residue."


Residue is the industry term for trash, and this accounts for 20 percent of what comes into the sorting facility. That’s as much trash as there is glass, more than the percentage of plastic or aluminum.


This is a problem. Remember how most of our recycling used to go to China?


“The premise for the Chinese banning some of these materials was the contamination that they were receiving," Bell explained.

So China is no longer accepting mixed paper and plastics. Waste Management and other large recycling companies are looking for new buyers for those materials. There are more international markets popping up, in places like Vietnam and India, and there are some new domestic ones, too.

But Herrera explained that now all clients want the recycling to be free of trash and contamination.


"If we don't get help from the public, not only does it get more and more and more expensive, it also gets really ineffective," Herrera said.

It takes a lot more time—and many more people—to meet the expectations that a stack of newspaper is really just newspaper.


EDITOR'S NOTE: This is the first in a series about recycling.