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The Hunt for Green

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

The trucks rumble through the gates of Waste Management Recycle America's plant in north Denver, lining up for their turn at the scales. A driver for the City of Thornton tailgates one from the City of Denver. Dump trucks from commercial and residential collection routes across the metro area squeeze past semis from Greeley and Vail.

One by one, they hit the scales, then jettison their cargo at the maw of the cavernous plant: an avalanche of paper and glass, plastic and metal. Each load adds to an already humongous heap of trash in the hangar-like entryway -- a hulking, jagged Mount Massive of trash, a multi-storied monument to a disposable culture.

Phone books. Busted-up cardboard boxes and packing materials. Pop cans, milk jugs, water bottles, beer bottles. Itsy-bitsy cat food tins, licked clean. Sludge-crusted five-gallon cans of industrial-strength beans. Flattened cereal boxes and swollen, well-thumbed skin mags, Cap'n Crunch shipping out with the swabbies of porn. Urgent but never opened notifications from mortgage companies, credit-card hawkers, the Publisher's Clearing House. Catalogues from L.L. Bean and JC Whitney. And everywhere you turn, piles of newspapers -- an endless ripple of yesterday's headlines and grocery coupons, auto sales and cut-rate editorials. Acres of words and pictures, no longer needed even for puppy training, just tossed, forgotten, like the stumps and scraps of a leveled forest.

"We see more newspaper than anything else," says Jose Herrera, the plant's manager. "Right now it's about 60 percent of our volume."

A shift change is under way inside the plant, which means Herrera's voice is actually audible for the moment, while the maze of conveyor belts and sorting screens behind him stand idle and the mountain of trash spreads. In a few minutes the contraption will jump to life, bells ringing and buzzers bleating, and dozens of men and women will begin picking through the recyclable materials being shoveled toward them -- a process that is highly automated and incredibly labor-intensive at the same time.

After pulling out the junk the machines can't handle -- plastic bags, wooden palettes, coffeemakers, paint cans and other unsanctioned jetsam, all headed for the landfill -- the sorters send the rest on in increasingly homogenous currents of fiber, metal, plastic and glass. Much of it will emerge from the back end of the plant in neatly compacted bales, suitable for shipping by rail or truck.

Blocks of crushed aluminum, the most prized of all recyclables, headed to Anheuser-Busch. Bales of newspapers, bound for paper mills in the Southwest and Northwest, to be churned into more newsprint or paper towels or toilet paper. Tin cans to Utah, to a company that makes rebar. Depending on quality, cardboard can get turned into more corrugated boxes or increasingly cheaper grades of chipboard. Bundles of what's known as mixed paper, made up of junk mail, phone books and other low-fiber materials, might get chopped into insulation or processed into a material used to cover Sheetrock or drywall; most likely, the low-grade stuff is headed for China or some other not-too-picky overseas market.

"There are few mills that are willing to take a mix like this," Herrera says, nodding at a freakish cube of phone books, catalogues and chipboard. "There's very little fiber content there."

Opened two years ago at a cost of close to $5 million, the Denver plant is one of a few dozen Waste Management single-stream material-recovery facilities, or MRFs, around the country. The local operation now handles 10,000 tons of recyclables a month, from commercial as well as residential customers. Twenty percent of that total comes from the City of Denver itself. Essentially, Waste Management buys Denver's recyclable trash for a modest price, then sorts it and resells it as raw materials to manufacturers at a higher price.

Like many cities, Denver has embraced the single-stream system as a way to promote recycling and cut landfill costs. The idea is that if residents are no longer required to sort the stuff they recycle -- newspapers in one bin, plastics in another, and so on -- the volume of materials collected goes up dramatically. The move required rolling out thousands of 65-gallon purple carts to residents and acquiring a fleet of automated trucks to empty the carts, but city officials expect the investment to pay off handsomely.

"We're moving up the curve," says Charlotte Pitt, recycling-program manager for Denver's Department of Public Works. "It costs less to pick up recycling than to pick up trash. We're looking at $25 a ton to pick up recyclables, while going from curb to landfill costs us $50 per ton. We pick it up whether it's in the garbage can or the recycling cart, so this is reducing the use of the landfill and offering other environmental benefits."

There are strong economic arguments for going single stream, and hundreds of cities have embraced the concept in recent years. But among some manufacturers and recycling advocates, the move has been viewed with skepticism and even alarm. As the volume of trash headed for the MRFs shoots up, so do issues about the quality of the materials, the degree of contamination and the difficulties involved in sorting the mess.

"There's a split in recycling about single stream," says Susan Kinsella, executive director of Conservatree, a California-based non-profit advocacy group. "It's generally a good arrangement for the local government, and they're often very tight with the collectors. Collecting more materials at curbside is generally what people think is recycling."

But just diverting tonnage from landfills isn't recycling, Kinsella insists -- particularly if a significant percentage of the stuff ends up in another landfill somewhere down the line. What happens inside the plant determines whether yesterday's containers and reading matter are put to "best use" and get a new life, or simply wind up as a fancier kind of trash.

Judging by the truck traffic alone, the new program is catching on big in Denver. The city's bold plunge into single stream is a good indication of the promise -- and the headaches -- of trying to go green and stay in the black at the same time.

Out in the parking lot of the Waste Management plant, workers are de-casing stacks of brand-new cans of Pepsi. This is part of WM's "full product destruction" program. The cans will be emptied and crushed, the liquid mixed into compost, the cans and boxes dispatched for recycling, all because of some fizziness defect in the batch. This is also done -- steady, Hoss -- to cases and cases of beer that's past its expiration date, although sometimes Coors takes the decanted beverage and puts it through an ethanol recovery process.

Full product destruction is recycling for purists. It eliminates one side of the recycling triangle emblem that's carried on a host of consumer items these days; the goods go straight from production to reclamation, without the consumer being involved at all. Most recycling programs are much trickier and messier, since they involve trying to recover materials after insatiable consumers have already had their way with them.

According to EPA figures, the United States generated 246 million tons of municipal solid waste in 2005. That's more than 1,600 pounds of crap per citizen. Almost a third of it was recycled; the rest was burned or ended up in a landfill somewhere. Thanks largely to aggressive state and local programs designed to divert residential recyclables from landfills, the percentage of trash that's recycled nationally nearly doubled in the 1990s, but the numbers have crept upward only slightly in recent years. Part of the problem is that 35 to 45 percent of the total waste is generated by the commercial sector, and many businesses still recycle only a fraction of what they throw away. For example, more than half of all office paper still isn't recycled, although it easily could be. Around 90 percent of the printing and office paper in use right now has no recycled content at all.

Statistically, Colorado has a particularly miserable record for recycling. The state ranks 41st in one magazine's survey of waste-management practices and generates up to 40 percent more trash per person than the national average. Industry observers say that's because of cheap landfill costs and a Western guzzle-and-toss-it sensibility.

"The cost of throwing things away is quite low here, compared to many areas of the country," says Marjorie Griek, executive director of the Colorado Association for Recycling. "There's more land availability."

Griek notes that some cities have embraced recycling in a big way, including Aspen, which "is doing enormous things to extend the life of its landfill," she says. "They're not going to be able to site another one in that county because of the topography and the cost of the land." Boulder, Fort Collins and Loveland also rank high on her list. Some municipalities require private trash haulers to offer recycling, too; some impose "pay as you throw" fees on residents that are determined by the number of garbage cans you use, providing an economic incentive to recycle. But Griek is frustrated by the lack of any state leadership to help coordinate recycling efforts.

"There's simply no financial support," she says. "There's no state agency that's responsible for recycling. There are no goals set. Job creation is one of the huge benefits of recycling -- and there's a lot of entrepreneurial spirit here and a lot of materials that industry could use. We just don't know how much."

In California, garbage fees and a state mandate to drastically reduce landfill volume have produced sophisticated recycling programs. San Francisco even provides its residents special carts for food scraps, lawn trimmings and other compostables, which make up a quarter of all municipal solid waste. Denver's voluntary program has been much more limited. Back in the days of the sort-it-yourself purple tubs, officials estimated that public participation was as high as 50 percent -- but no one knew for sure, since the handy containers had a way of disappearing. A more realistic figure, Charlotte Pitt says, is around 40 percent.

The city's decision to go to single stream two years ago was driven primarily by rising operational costs. The volume being collected had leveled off several years ago, but the Department of Public Works was seeing an alarming rate of job-related back and leg injuries. "Our guys were picking up five to six hundred bins a day," says Pitt. "Not only that, it was a one-man operation. So they were stopping the truck, hopping out, emptying the bins, getting back in. There were a lot of ankle injuries."

After studying what other cities were doing, Pitt recognized that going to automated collection of big carts on wheels would save drivers and residents a lot of strain. It also cut the number of drivers needed, since each route could cover more blocks than the manual system allowed. And, of course, it encouraged residents to recycle more, since the confusing sorting process at their end was eliminated and the capacity was increased.

The key to the deal was finding a recycling plant willing to take the unsorted trash. Waste Management, which had already been doing some sorting of the city's trash, stepped forward with a commitment to retool its plant for single stream. Under a ten-year contract hammered out with the city, WM now pays Denver a minimum of $33 a ton for its recyclables. That's less than the figure on the old contract, but with overall volume going up, it actually translates into a larger payoff.

"We knew we would see a per-ton drop in price, because they have to do the sorting," Pitt says. "But we also knew our tonnage was going to go up."

With more than 66,000 carts on the streets -- and another 1,000 residents still waiting for carts -- participation in the new program is hovering around the same level as with the previous system. (The city doesn't collect from apartment houses with more than seven units, leaving about 160,000 residences in all eligible for the program.) But since 2004, the last full year of the purple tubs, Denver has seen close to a 40 percent rise in the amount of recyclables collected -- and a corresponding drop in materials headed for the landfill. Pitt expects the investment in carts and trucks to be offset by the operational savings and the rising revenue stream from selling more trash; she predicts the program will bring in $800,000 in revenue in the coming fiscal year.

Actually, she adds, the $33-a-ton figure is slightly misleading. Waste Management deducts 5 percent from the price of every ton for the inevitable contamination problems. It's not uncommon for unaccepted materials, mostly plastics, to find their way into the carts. Many consumers still don't understand that Denver's system takes plastic beverage bottles, but not plastic margarine tubs or paint buckets, and the 1-7 classification system stamped on plastic containers is little help in deciphering the rules.

"A plastic bottle and a plastic tub, while each may be labeled number one, are made with different processes," Pitt says. "One is blow-molded, the other is injection-molded. What you see are different melt temperatures and different chemicals. Bottles recycle easily, and there's a high market for them. Until we can take all the plastics, the issue is going to be there."

Cameras mounted on the city's recycling trucks allow the drivers to see what's in each cart as it's being emptied. So far, the level of abuse has run far below expectations; one analysis last year found the contamination rate averaging about 2 percent. Pitt attributes the low figure to a successful education program.

"We're not worried about people who put items in the cart because they thought they were recyclable," she says. "We're looking for people who are using the cart for garbage. Our goal is education first; if they continue, we take the cart away."

Plant manager Herrera estimates the total amount of contaminants coming into the plant at around 5 percent, but he figures a disproportionate amount of that comes from commercial customers dumping appliances, lumber, hardware, you name it. In a throwaway society, almost everything shows up at the recycling plant sooner or later.

Even throwaway people. Last November, sorters at the plant came across the most unsettling discovery of all: a corpse on the conveyor belt. Police were called immediately, and first impressions suggested that it might be a case of foul play and a body dump. But further inquiry indicated that Robert Henderson, 63, formerly of Arvada, was homeless and known to sleep in a dumpster used for recycling newspapers because it was warm.

The Denver Coroner's Office concluded that the death was accidental. "It is likely he was picked up by one of the trucks," the forensic pathologist wrote, "and suffered blunt force injuries during the pickup and transport to the recycling center."

When the second shift starts inside the plant, it's easy to see how the unfortunate Mr. Henderson made it to the pre-sort. Front-loaders attack the mountain of trash from two directions, nudging it toward a concrete bunker. At the far end of the bunker, a steeply pitched conveyor known as the incline hauls the indiscriminate mass of junk to a platform high off the ground. There a team of pre-sorters pulls items off the line that don't belong there, especially things that can get tangled in the machinery ahead: garden hoses, electrical cords, even shredded paper.

"I was surprised to see the amount of residential shredding going on," Herrera says. "Everyone's worried about identity theft."

One of the biggest problems at this stage, though, is something Waste Management has agreed to recycle: phone books. They can jam in the screens that separate one kind of material from another, so workers snatch them off the line in the pre-sort and send them down a chute to a collection bin below. The directories used to go to drop-off sites, but a staggering number now come mixed in with the rest of the single stream -- up to 500 tons of the fat tomes a month.

The belt moves slowly at first, gradually gaining speed as the sorters get accustomed to the pace. It's a bit like watching Lucille Ball try to keep up with the chocolates on a classic episode of I Love Lucy, a reference that Herrera has heard more than once but finds elusive. ("A lot of people have mentioned that to me," he sighs. "I've never seen it.") At its peak, the plant processes thirty to forty tons of material an hour.

A few feet past the pre-sort, the first screen awaits, a spinning whirligig of large, star-shaped discs. The principle is simple: big stuff goes over the top, everything else falls through. At this juncture, the big stuff tends to be cardboard, which ends up on its own belt, Conveyor 15, headed toward the baling machines. But the system is far from flawless; smaller scraps of cardboard can fall through, while some plastics might be stuck to cardboard and go over the top. So there are quality-control folks waiting beyond the screen to pull non-cardboard off Conveyor 15 and return it to the stream via another conveyor, and so on.

Adding commercial clients has more than tripled the amount of cardboard the plant sees, Herrera says. And going to single stream has more than quadrupled the workforce in the plant. "There used to be three or four sorters, one baler, one forklift operator," he recalls. "Now we have twenty sorters, two balers, four lift operators -- and that's on fiber alone. The container line runs another ten people."

The next screen has smaller stars, with tighter gaps between them. It's designed to send most of the newspaper hurtling over the top to its own belt. Some large containers make it over, too, and will have to be retrieved and sent back into the main stream, but the critical objective at this point is to get the paper away from the increasingly fragmented glass, which falls through the screen. "Glass is the worst contaminant we can have on newspapers," Herrera says. "The worst."

In theory, the remaining paper products are winnowed out at the third sort, where a screen with a different pattern of stars is hooked up to a blower that helps to propel the paper over the top, while containers made of plastic, glass and metal fall through. In practice, there's a return belt for the containers that fly over the top and some additional sorting on the container line for paper that falls through. But most of the paper is now headed for balers on one side of the plant. The blocks of newspaper that emerge from the back of the plant, destined for paper mills, will sell for around $125 a ton, and cardboard commands a similar price. The mixed paper will probably be shipped overseas and sell for around $75 a ton. (Waste Management has a second plant in north Denver that deals primarily in high-grade office paper and cardboard; it also offers public drop-off for phone books, cardboard and, for a fee, electronic waste.)

On the opposite side of the plant is a further network of belts, platforms, screens and catwalks, where the feverish separation of containers commences. A powerful magnet sucks tin cans into their own silo. A device that Herrera calls an eddy current exerts a magnetic field that repels aluminum cans; while the rest of the materials drop off the belt to another system below, the cans hurtle through a chute and are spat out in a cage, with sound effects like a popcorn popper gone berserk. Plastics whirl through a vortex designed to send the heavier materials downward while the lighter stuff, fugitive fiber and aluminum, heads elsewhere.

When it's over, Waste Management has a bunch of other well-sorted commodities for the loading dock. Clear plastic beverage bottles, which go for as much as $340 a ton, thanks to the hike in oil prices. Colored plastic, around the same price. Milk jugs, maybe $600 a ton. Aluminum, $1,900 a ton, but it's a small percentage of the total volume.

What's left? At the far corner of the plant, emerging from the noise and dust and seeming chaos of the sort process, is a fine rubble of busted glass, tattered labels and caps. A waterfall of glass, pouring from a final conveyor belt into its own bunker and headed for the Denver landfill, which is located in Arapahoe County and run by Waste Management.

The plant is able to sell 300 to 400 tons a month of intact bottles or large fragments to Rocky Mountain Bottle, a manufacturer half-owned by Coors. But most of the glass emerges from the plant too fine, too mixed up with ceramics, rock or other contaminants, to be of any commercial value. Every month, Waste Management hauls a thousand tons of the stuff to the landfill. Herrera says it's used as landfill cover because it's cheaper than dirt.

"There's a guy on the line pulling the big pieces of glass we send to Coors for recyling," he says. "But it's impossible, for the volume we handle, to manually sort the rest and produce the kind of quality they can accept."

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."

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?

"All of the [MRFs] will tell you they're doing a great job and they have just a little residue. There's certainly been an improvement in the technology. But there's less attention to quality, and the market is no longer dictating the quality or the volume of the material."

Like Gertman, with whom she co-authored a "best practices manual" for single-stream recycling, Kinsella would like to see cities such as Denver work closely with the MRFs and the mills to develop strategies to combat downcycling. "We need to turn the system on its head," she says. "Instead of a garbage system with recycling tacked on, it should be a resource system with a little bit of garbage. Nobody's operating it as a whole system."

Operating a whole system with the aim of "zero waste" has long been the goal of Boulder's Eco-Cycle, a pioneering advocacy group that's one of the oldest and largest non-profit recyclers in the country. The group contracts with Boulder County to handle its recycling and is currently building a state-of-the-art material recovery facility that will focus on "best and highest use" practices. "Downcycling is a reality in the recycling industry," says Eric Lombardi, Eco-Cycle's executive director. "It's something we would like to minimize."

Lombardi consults frequently with the commercial sector, showing businesses how they can commit to environmental savings that also produce bottom-line savings -- for example, by making their own purchases more predictable and recyclable, reducing their waste costs drastically. "Businesses will do it," he says. "They're glad to do the green thing, if you'll hold their hand while they're getting used to it."

Ultimately, he says, cities should be aiming for the kind of three-pronged approach now used in San Francisco: one collection for wet compostables, another for dry recyclables, and a dwindling stream of trash headed for the landfill. According to the EPA, landfills are now the primary source of methane from human activity -- and methane, a greenhouse gas, figures prominently in all global-warming scenarios.

"Who's paying for that pollution right now?" Lombardi asks. "No one."

Eco-Cycle is now planning for a huge "zero waste center" in Boulder County. Instead of a landfill, it would provide composting and demonstrate recovery of "the 90 percent of the discard stream that actually has market value as a feedstock material for industry," as the Eco-Cycle website puts it.

"This is a global problem," Lombardi says. "We think this is where the nation needs to go. I'm a great believer in the private sector, but the government sets the rules about what it expects from recycling. The government has to step up."


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