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The Hunt for Green

Sorting out the payday in Denver's new recycling plan.

Dealt with separately, glass can be one of the easiest materials to recycle. But it has become the bane of many single-stream plants. It gets pulverized by the sorting machines into a fine grit that wears down the equipment. And sometimes it finds its way into the finished product, wreaking havoc in paper mills and elsewhere.

The contamination problem is so severe that some municipalities have banned glass from their recycling bins, and some manufacturers are questioning whether single stream is truly a better form of recycling or merely a way of shifting the costs to them. One study commissioned by the American Forest & Paper Association found that single-stream products seem to be driving down the quality and value of recycled paper products produced by mills, while hiking the disposal costs of those mills. One company found the amount of contaminants in its recycled paper had doubled, resulting in thousands of tons of unacceptable material going to the landfill every year, at an annual cost of half a million dollars.

Herrera says it will require expensive new optical scanning equipment to recover more glass, and the company will have to decide when the volume is sufficient to justify the expense. Keeping customers' confidence in the purity of recycled materials is a key part of his job; he routinely breaks down finished bales to see what kind of mix is coming out of the plant. "It becomes pretty pricey if the mills have problems with our materials," he says. "I want to make sure we don't have too much other fiber with the newspaper, glass on the paper, rocks in the glass, any of that."

High on fiber: Waste Management operations manager Jose Herrera (above) says the move to single stream quadrupled his workforce; Denver's recycling czar, Charlotte Pitt (right, flanked by city employees), found that automated trucks reduced injuries.
Anthony Camera
High on fiber: Waste Management operations manager Jose Herrera (above) says the move to single stream quadrupled his workforce; Denver's recycling czar, Charlotte Pitt (right, flanked by city employees), found that automated trucks reduced injuries.
The junk stops here: Trucks from across the Front Range unload at Denver's single-stream recycling plant (above); inside, workers sort through thirty tons of recyclables an hour.
Anthony Camera
The junk stops here: Trucks from across the Front Range unload at Denver's single-stream recycling plant (above); inside, workers sort through thirty tons of recyclables an hour.

The glass problem is part of a larger issue in the single-stream debate known as downcycling. Downcycling occurs whenever products are mixed or contaminated with inferior materials -- for example, when high-grade office paper is mingled with lower-fiber materials -- and thus are returned to the marketplace in a far less valued form. That leads to more clear-cutting of forests to make more office paper, more energy consumption, and so on. In order to keep costs under control, single-stream plants engage in many kinds of downcycling, such as turning glass bottles into landfill cover. But recycling advocates say it can be cost-effective, as well as environmentally prudent, to channel materials to their "highest and best use" -- if only the municipalities that contract with the recycling plants would insist on it.

"A valuable resource shouldn't go to a landfill," says Richard Gertman, president of Environmental Planning Consultants in San Jose, California. "It's silly to collect it with the intent of taking it to a landfill."

Gertman points out that color-sorted glass bottles can sell for as high as $80 a ton; as smashed-up aggregate, the glass is worth only around $3 a ton. Many recyclers take the position that the glass is already broken up in the collection process before they get it, but Gertman's own research indicates that most of the damage occurs in the plant. "It's still pretty whole on the truck," he says. "The problem is when it's dropped on the concrete floor and it's getting pushed around. The front-loaders tend to break a lot of glass, and the star screens have that effect, too."

The state of California is funding Gertman's effort to develop a low-impact sorter for glass, a special conveyor for sorting the glass right out of the truck that he believes could produce a 95 percent recovery rate. But for such a system to be introduced to the recycling plants, the cities that provide materials to those plants have to require that the glass be recycled properly. And his conversations with Denver officials have left him with the impression that they don't want to dictate such concerns to the private sector.

"The city has taken the stand that once it's collected, it's recycled," Gertman says. "They should care about where the materials go and whether they're recovered."

But Pitt says Denver's contract with Waste Management does require that its glass be recycled; use as landfill cover is prohibited. "We're not naive enough to think that 100 % of it gets recycled," she says. "But we do think the economics of it will encourage them to be more efficient."

If Gertman's design could create a sizable leap in revenue from glass sales, you'd think the recycling plants would snap it up. But it isn't that simple. The priorities of many players in the single-stream movement seem to be centered on upping the volume of what comes in the front gate, not the quality of what comes out of the plant. Someone, after all, is willing to take even the most degraded mess of mixed paper.

"I've had lots of people say, 'Don't even talk about this,'" says Conservatree's Kinsella. "But the governments don't talk to the manufacturers about what they want. They're just concerned about keeping it out of the landfill and fulfilling their mandate."

China is willing to take much of what the recycling plants produce -- and has the cheap labor to do whatever additional sorting is required. "But no one's looking at the long term," Kinsella says. "What if the plants that use recycled materials in Canada and the U.S. close down because the materials are going abroad?

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