With changing markets for end products demanding higher-quality feedstock and collection operations trying to reduce costs, material processors might feel caught in the middle.

By Lynn Merrill

In this ever-changing world of greenwaste and commingled recyclables processing, material processors must meet challenges in collection operations and market conditions while improving efficiency, lowering costs, and maintaining profitability. New technology is helping, but reliability and capital costs also have to be considered.

Processors are often caught between collection systems designed to improve efficiency and control costs and end markets that demand high-quality, low-contaminant materials. Over the last decade, they've had to adopt and adapt to external factors beyond their control.

When recycling programs started, processors only needed to perform minor cleanups on material that was source-separated at the curb. A simple processing system with a multistation manual sorting line leading to a baler was often all that was necessary. But as collection managers looked at the cost efficiency and effectiveness of multiple compartment trucks, they realized that they needed to improve their productivity.

Multicompartment trucks that segregated glass‹often by color‹plastics, metals, and newspaper gave way to two-stream systems that utilized either separate or split-bin trucks. This innovation allowed the collection of more material and improved the payload per truck while reducing the potential for repetitive injuries as operators hoisted bundles of newsprint or glass into compartments. It often meant collecting a larger variety of paper products, so newspaper, mixed papers, and corrugated cardboard had to be sorted at the processing facility, as did the many grades of plastic and the colored glass.

With the final push on the collection side toward single stream, the processor now has to figure out how to reconfigure his processing lines in order to separate mixed recyclables while continuing to make a variety of products for sale to end markets.

Greenwaste processors often fare no better in trying to improve operation efficiency. Many communities are shifting from manual collection of greenwaste, which allowed contaminants to be removed at the curb, to semiautomated or automated collection using bags or carts. Although these programs help improve the collection efficiency, contamination increases because people sometimes bury contaminants within the carts. Many programs attempt to screen out contaminants, but once the load is dumped in the hopper, it's up to the processor to get it out. Bits of glass, metal, and plastic in the finished product are not tolerated, and the ability to screen and remove these materials from yardwaste is labor-intensive.

Technology, but at What Cost?

Fortunately for processors, equipment manufacturers are addressing the growth of single- or dual-stream material mixes as well as the growth in the volume of materials collected through these programs. More automation is finding its way into the processing facility, thus reducing the operating costs by reducing the number of manual picking stations, but the equipment translates to higher capital and maintenance costs. This technology might be out of reach for some lower-volume processors, making them less competitive and ultimately driving them out of business.

Probably the single most effective automation technology recently introduced is the various screens available to sort paper products out of the line automatically while maintaining the appropriate contamination levels required by the various mills. Previously, corrugated cardboard had to be removed by hand from the system to allow other sorters to identify and remove newsprint and smaller papers from the burden line. When a screen or series of screens removes large pieces of cardboard, sorters can focus on smaller sizes and types of paper.

At the West Valley material recovery facility (MRF) in Fontana, CA, the installation of screens helped to increase productivity 200% while reducing labor costs significantly. The facility operates two sorting lines: one for the residential wastestream that has more containers within the stream and a commercial system that handles a larger volume of corrugated cardboard within the mix. "With single stream, the biggest issue is getting the paper away from the containers," states Eric Herbert, vice president and chief operating officer for Burrtec Waste Industries, based in Fontana, which operates the MRF. "This system does a very good job of that. It's got three separate sets of screens that segregate paper by newsprint and mixed paper and then separate out the containers so that we get a real good cut at the paper without a lot of labor. The other system that we put in was the commercial system that includes an [old corrugated cardboard] screen." The screen removes the large pieces of corrugated from the mix, allowing greater access to the remaining mix of paper.

The sorting lines at the 5,000-tpd facility were recently upgraded, replacing an early system that was installed in 1997. "The system that we put in originally was pretty much just straight conveyors, so it was very much a manually intensive sorting operation," states Herbert. "The newer generations have been significant enough to warrant making that investment for that savings that you can hopefully realize over the long term." Technology able to screen paper away from containers impelled the upgrade, he adds.

Screening technology played a big part in operation of the new Eco-Cycle facility that provides recyclables processing for Boulder County, CO. According to Jeffrey Callahan, manager of the Boulder County Division of Resource Conservation, there were two goals for the new county-owned facility. "One of the things we did when we built the facility is that we would commingle all of containers," he states. "We needed the equipment to be able to manage commingled containers, which also include the paper milk cartons. The second was we wanted to be able to grow the system. We process about 40,000 tons a year, and that's been fairly stable. We wanted to have the ability to make it more convenient for the residents and businesses to bring in materials and for us to be able to separate them effectively."

To accomplish this, Eco-Cycle, a nonprofit recycling organization, installed a corrugated screen. "Material comes in from the commercial sector very rich," Callahan states. "That screen then automatically separates all of the corrugated from the rest of the paper, and then that paper is conveyed back to our main sorting line, so that gives us some flexibility. In November, the City of Boulder went to a complete paper mixture. We put that on the corrugated separator, and that separates out all the corrugated from the rest of the paper that then goes off to be sorted."

Callahan doesn't see a future in converting the system to a single-stream facility. "There was some discussion in the environmental community within months after we built the facility that we should retrofit it and make a single-stream facility," he says. "We have a wonderful commingled container line and very high participation rates. We don't control any of the collection costs, so if we spend capital funds to improve the system for a single stream, all the benefits fall outside our control."

Responding to Customers at Both Ends

A commercial MRF operation and a residential MRF operation

As a quasi-municipal entity, the Regional Waste Systems facility in Portland, ME, is sensitive to the needs and desires of the 21 towns and cities it services. It's an integrated system that operates a recycling facility, a waste-to-energy facility, an ash-fill balefill, and a composting facility for leaves and yardwaste. "We process about 20,000 tons of recyclables a year through our facility, which has two sorting lines," says Eric Root, director of materials recycling. "One line is for paper and one for a mixed container stream. On the paper side, we are making primarily number-8 news that we sell to paper mills here in the state of Maine. We also process cardboard and mixed paper, and we make a number-6 news product from some of the material we receive."

The recycling facility was recently upgraded not only to address productivity improvements but also to address safety and ergonomics concerns. "Our throughput went from 3 to 4 tons per hour to 12 tons per hour," reports Root. "All kinds of stuff were improved by doing this upgrade. We fairly dramatically affected our workers' compensation claims, my turnover is down, and my personnel problems got easier. The other thing: It buys us much greater flexibility."

This flexibility became critical when one of the facility's customers experienced some trouble. "One of the major paper mills in Maine has filed for bankruptcy," Root states. "That was an important market for us, which leaves us in a position of scrambling for new places to go. I can't imagine trying to have the flexibility we have now with our old system; that truly would have been a nightmare. In terms of marketing, it is important to have flexibility, and it does give us the ability to move materials into a number of different streams and change the way we sort based on market conditions as they change."

Some of the changes were driven by the municipalities' demand that the facility more than double the amount of recyclables it could accept in order to meet anticipated supply. "Our largest municipality very much wanted to change the way they collected and processed waste, both to control their costs and to do a more environmentally responsible job," says Root. "They looked at other municipalities, went to national seminars, and said, ŒHere's what we want to do.' I appreciate the opportunity to do a better job, and that is what we are doing."

Root believes that the critical issue in successfully running a processing facility is understanding costs. "A town may want to do a two-part sort instead of a three-part sort; there's an economic consequence to that. If they are willing to pay it, so be it. That's OK. Now there's a limited capacity for that kind of flexibility. But if we understand what the demand is and what the cost implications of different deliveries are, we can, on the one hand, charge appropriately. On the other side we can understand the markets that my buyers are setting up and what the cost implications to meet those criteria are and make appropriate and flexible choices between them. Then it is an economic balancing act. The nature of what we do is to try to understand costs and direct people so as to minimize those costs or maximize our returns."

A growing community can push the need for improved processing throughput and lowered costs and justify the investment in advanced technology. The Palm Beach County (FL) Solid Waste Authority manages the collection and disposal needs for a community of 1.1 million through an integrated system that includes Class I and II landfills, a waste-to-energy facility, a co-composting facility, and two MRFs, one of which serves the residential stream while the other serves the commercial stream. The county utilizes a two-bin residential recycling collection system, with one bin for paper products and one for other commingled items.

"The residential facility is doing about 100,000 tons per year while the commercial facility is doing another 25,000 tons per year," reports Patrick Carroll, assistant director with the authority. "The residential facility was opened in 1990. We quickly outgrew that system, and about four years ago, given the growing tonnage numbers and the fact that our existing facility was very overburdened, we decided to do a major modification and expansion to our recycling facility."

This expansion included a 27,000-ft.² addition that added two processing lines to the existing two. "The bottom line was it increased our processing capabilities in terms of the fiber stream to about 40 tons per hour with the two systems combined," states Carroll. "On the commingled side it increased our throughput from about 6 tons per hour to 14 tons per hour."

One of the key components added to the system was an optical sorting system for broken glass. "We got some grant money from the State of Florida and were able to utilize that to purchase and install this optical sorting station," says Carroll. "We're recovering the clear portion in the mixed broken because that is the most valuable. It was also about 60% or more of the mixed broken that was being sorted out. It takes the material and spreads it out into a very thin sheet. The optics identifies what to save and what to kick out. There are approximately 96 stations equipped with a solenoid run by pneumatics. That piece of glass is identified, and it's kicked out with a burst of air. It is very effective, and what we get out of it is a very clean, clear glass stream. It captures about 80% to 85% of the clear fraction that's in the wastestream. We probably would not have done that had it not been for the grant monies we got, but it has worked out, I think, very well for us."

Carroll recognizes that his role requires him to keep both sides satisfied. "We're the guys in the middle, and we have to kind of deal with both ends of the spectrum," he says. "In one respect we have to process what's brought to us and make a saleable product out of it. But the other part of our mission is we have to sell what we make too. It is kind of a double-edged sword. I don't think the two sides are ever going to be totally going in the same direction just because there are different forces that kind of motivate each of those sides. The public wants to be able to recycle more and different kinds of items. As the authority, we want to try to increase our recycling rate to the extent that it's feasible and viable to do so. On the other side, the end markets are going to demand better and cleaner material because that helps keep their costs down. I guess the best thing that we can hope for, as the guy in the middle, is to try to maintain that balance between keeping our customers happy and keeping our buyers buying on the other end."

Lynn Merrill is director of public services for the City of San Bernardino, CA.

MSW - Elements 2004