The devil may be in the details, but so is successful single-stream processing.

By Lynn Merrill

To work right, single-stream processing needs the right amount of investment in equipment and processes within the facility to meet the market and pricing specifications for the materials, and then it requires constant public education to cut down on the contamination of materials.

While there are those who remain skeptical about the efficiency and effectiveness of single-stream versus other collection approaches, the single-stream approach has become a fact of life for those charged with collecting, processing, and marketing recycled materials. The challenge the industry now faces is fine-tuning the mix of strategies in order to turn out materials that have a high value on the back end while being cost-effective on the front end. The mix of strategies will be different in each community.

"A recycling program will not be sustainable if you don't make it as cost-effective as possible," states Lisa Skumatz, an economist and principal with Skumatz Economic Research Associates in Superior, CO. "You can't make them so Cadillac that they take a monster subsidy and then disappear in a couple of years because the budget is not there. It's really important for us to re-examine our programs and try our best to make them as cost-effective as possible. Not to say that cost-effectiveness is the only monitor, but if we have something that is dramatically far from cost-effectiveness, we're going to have a problem over time."

Skumatz's firm provides assistance to cities, counties, and the private sector with evaluation of programs, including planning, scenario analysis, and cost-effectiveness assessments. "We've done a lot of studies using information from up to 1,300 communities around the country on their recycling programs, what their costs are like, and what specific impact from program changes can be expected. We do what used to be called 'recycling planning assessment models,' but I'd like to think of them as integrated planning models. We try to look at what materials are still left in the wastestream and what makes sense for pulling those out."

Over the past several years Skumatz has completed several studies of single-stream systems that have included examining the impacts on collection, processing, tonnage, costs and the markets and mills. "We've been finding that single stream collects more material than a dual-stream program at the curb, and it also does sell at lower cost than two-stream programs. In some cases there's an increase in contamination, but in many other cases there's not, as demonstrated by the processing at the MRF [materials recovery facility]. We find that single stream is getting painted with a conclusion that single stream leads to high contamination. With no qualifying factors, that's not a conclusion that can be justified. I think there are some single-stream facilities that produce high-quality materials and some that produce lower-quality materials than dual stream. We're finding that if you're replacing an older dual-stream facility, in many cases you can have an improvement in contamination. If you're dealing with an older facility, many times they're using obsolete or worn-out technology for the container stream and so you end up with improved quality [after replacing equipment]. What we're also finding is that while there's some report of increase in MRF costs, we're finding that the gate fees to communities are often not increased. In fact, about half of a set of cities that we interviewed said that there had been no change in the fees they were seeing at MRFs."

In single-stream programs, education plays a key role in managing contamination at the front door. "One of the things that seems to be a factor in how clean the material is is education by the program at the community level," Skumatz says. "We've been on sites with various MRFs and we'll look at two different piles of material coming from two different cities. The difference in the contamination of the two communities is dramatically different. Education was cited over and over again as something that the MRFs wished was happening and think would pay off."

While education of the public has a dramatic effect on the quality of materials hitting the front door, the commitment inside the facility to generate top-quality materials has to be there as well. "Cleanliness of the materials coming in [is a factor], but sorting is the real key here," Skumatz states. "It depends on how modern the equipment is, how many steps they're willing to go through, and if they have some post processing that cleans it up even more, then that facility is going to do better. If they have a strong commitment on the part of the plant manager to manage the facility well and make sure that people are doing the job right, that the equipment is performing up to snuff, and that material isn't going through too fast, that facility is going to do better. That's true with single or dual stream but it's particularly true with single-stream material. You can make a single-stream facility do very well if you do things right."

According to Skumatz, the markets need to tell MRF operators that clean materials will command premium pricing, thus justifying the investment in the facility. "I would argue that if clean material is a priority for a particular purchaser, then that particular purchaser can get cleaner material if they offer a price premium. If they don't offer a price premium, then any MRF that invests in extra steps, equipment, or labor is over-investing. If they were owned by shareholders, those shareholders should probably get upset with that MRF for investing that extra money because the market doesn't demand it. If all clean and dirty materials are going to be accepted at the same price, anyone who produces a cleaner material with no price premium is admirable, but from a financial status, the market signal is just not there."

Target: Zero Residuals

As the fourth-generation member of his family in the recycling business, Michael Benedetto, vice president of TFC Recycling in Chesapeake, VA, understands the need for improving the quality of materials that come through the company's four processing facilities. His company was the first to install a single-stream processing system on the East Coast to utilize disc screens. "My great-grandfather came over from Italy in the late 1800s and started a recycling business in New York City," Benedetto says. "My dad broke away from the family business and came down south, in 1973. We have four operations now [in Chester, Newport News, and Chesapeake, VA, and Durham, NC]. We're currently handling somewhere in the 12,000-tons-a-month range. We do recycling and waste-removal services. The majority of our business is curbside collections. We collect from about a half a million houses, run 120-plus trucks, and then we've got another 200,000 households of recyclable material that's brought to us from the City of Hampton."

For Benedetto, single-stream processing starts at the curb, but contrary to popularly held belief, it doesn't require an initial investment in automation to be successful. "You can collect single-stream materials in an 18-gallon bin, which we're doing in the Richmond area," he says. "The driver still gets out of the truck, picks up the bins, puts it into a truck, brings it back in a single-stream form, and we process it there. In Virginia Beach, and in other communities here in Southhampton Roads—including Newport News, Hampton and now Norfolk and Franklin—they're utilizing 65- to 95-gallon containers. That additional capacity increases the recycling program, but there is some additional cost. Instead of buying a $5 bin, you're buying a $35 or $40 cart."

The greater challenge is getting a single-stream product to a marketable state, according to Benedetto. "We see people fail because they can't get the quality," he observes. "In some cases they didn't get the quality because they either didn't utilize the technology or didn't utilize it in the manner that it was developed. There are some old systems in place where people are positively sorting the material off the conveyor belt. Somebody is pulling off every single material and off the end goes nothing but trash that winds up going to the landfill. We don't feel that that's the best use of a single-stream program because of the high residue rates. If you utilize a disc screen, you basically can let all the paper go by and pull out the cardboard and the brown grades and then any containers that get through. All your newspaper, magazines, junk mail, and office paper goes right through the system and you don't physically have to touch it. That results in a much better quality product."

The typical arrangement of systems that TFC Recycling uses in its facilities starts with the material traveling up a conveyor belt to a pre-sorting station, where large pieces of cardboard and trash are removed. Then the material reaches one or more disc screens. "The disc screens that we have are at a 40-degree angle," Benedetto says. "The principle behind it is that the paper is flat, so it goes on up and across and anything that's round, rolls back, or falls through. We're trying to get paper going in one direction and non-paper going in another direction. On one screen we might try and get newspaper and large pieces of paper, so the spacing is such that anything smaller would fall through the openings. Then we go to a next screen and the discs are a little bit closer at the end at such a point where we're getting the majority of the small pieces of paper out. We'll get more containers going across the flattened milk jugs and soda bottles and we'll hand-sort that out."

Benedetto continues to push the residual rate downward through the use of technology. Currently he's seeing about a 5% residual rate, but he's not satisfied. "Our target would like to be zero," he states. "I think that we might get pretty close to that with some of the new pieces of equipment that are coming out." One of the systems that he's optimistic about is optical sorting. "It's come a long way," he says. "I don't know if it's there yet, but I do know a lot of people that are looking at it, and some people that have actually purchased the optical sorting systems. In the past, they'd want to separate out the bottles, milk jugs from soda bottles. The tons per hour that it could do was so small that it just didn't seem to make sense from a financial perspective. Now it seems like the technology is greater and there are better applications for it. We're revisiting and we'd love to see one installed and see how it's working."

Knowing What to Change in the System

Deffenbaugh Recycling serves the metropolitan Kansas City area, processing materials from drop-off programs, residential curbside, and the commercial sector. Its facility handles approximately 10,000 tons per month, with an expected growth to 12,000 tons and greater. The company provides curbside recycling collection service to approximately 140,000 households using 18-gallon bins.

In 2003, Deffenbaugh Recycling switched to single-stream collection, which allowed the company to collect the same number of households with fewer vehicles. As part of the conversion, the company eliminated glass from the curbside program, while adding a variety of paper materials that were not previously offered. According the Mike Clagett, recycling coordinator for Deffenbaugh, program economics drove the need to switch to single stream. "The curb sort method of collection is so costly that you have to end up underwriting curbside recycling losses with other company revenues," he says. "In today's business climate, you just cannot continue to do that. Curbside programs have to at least get close to making some economic sense or ultimately they just don't continue to exist in the long term. We felt like we had to make some significant and sweeping changes to put this thing on its own two feet."

Part of the changes included revamping the processing of the materials. "You have to be able to figure out how you're going to have to change your processing to accommodate a single-stream approach on the collection side," Clagett says. "We put in a Bollegraaf separating system and it essentially separates the fiber materials from the container materials on that system. The materials then go through another sort where we separate the aluminum, tin, and plastic from one another, and then the paper gets another separation before these materials run through a baling process. The system does exactly what we hoped it might. It does a great job of separating the container fraction from the fiber fraction, and we're delighted with that."

Initially, there was a slight decrease in the volume of materials that the company picked up at curbside, but currently volumes have gone up fairly dramatically on the fiber side as more households develop an understanding of what the program can take. Removing glass from the collection stream was a significant, positive change to the overall program as well by reducing both the potential for worker injuries from shattered bottles and the abrasive damage of the glass cullet on the processing equipment. "Glass has always been a problem for us," Clagettt says. "The value of glass is not good. Our glass is worth just under a penny and a half a pound. So, if you collect 300 tons of glass a month, you've got to figure out how to make that work and you just can't. Glass is imminently recyclable, but it has to make some sense from a dollar-and-cents point of view at some point along the line."

Removing glass from the collection program also helped reduce issues in the community, Clagett says. "Glass is a nuisance issue on the street when it gets broken and not picked up adequately, so it's a nuisance to the cities as well as to the homeowners. Going to this program has reduced the number of problems in the community, but it's also reduced a lot of the contamination inside the plant that we previously saw. We continue to take glass at our drop-off locations, but collecting it in our drop-off locations is a good bit easier simply because you don't get that glass inside your facility. That glass just gets dumped in bunkers outside the plant and then loaded into trailers and hauled off to the buyers. Taking it out of our curbside programs has been a big plus for us."

It's the Markets!

Processing recyclables requires meeting the needs of the end user. In many cases, those end users may be across the globe. But in Oregon they literally may be down the street and part of the economic fabric of the community. According to Andy Kahut, general manager of KB Recycling Inc. in Canby, the local government recognized the integrated nature between processor and mill. "Local government has always been very proactive on doing the right thing and putting all the stakeholders together in a meeting," he says. "Local government here in the [Portland] metro area has been very proactive in working with the mills to determine what's going to be the best way to go about commingling and getting efficiencies at the curb. From day one, the mills made it very clear that glass poses them many problems. It's really been a combined effort between the mills, local government, and the haulers to come together and work towards a good solution in keeping glass out of the paper fiber."

KB Recycling designed a new facility around the modified single stream. The 60,000-square-foot facility sits on 10.5 acres and handles 6,000 tons a month with 3,000 to 4,000 tons curbside commingled. "We have a custom sorting system," Kahut says. "Material will hit three different sets of screens before it goes out the door, probably 550 feet worth of conveyor. We have a steel OCC [old corrugated cardboard] screen that separates most of the cardboard out from the rest of the material that comes back down a transfer conveyor and over to a news screen. Our news screen is a little bit different in that it doesn't have rubber discs. It has polyurethane discs that are a little bit harder and we get a little bit better life than guys who use rubber. That material goes up a single-deck ONP [old newspaper] screen, then to a final sort. The containers go through that screen along with the smaller-size papers, to a fine screen that'll gather any glass that's in there. They'll do a manual sort for the plastic containers, a mechanical sort [using magnetic separation] on the steel containers, and that remaining paper product goes out and gets combined with the paper product off the news screen."

One of the challenges facing Kahut is providing sufficient curbside materials to ensure efficient operation, due to the volume of processors in the metro area. "We're kind of unique in Oregon because we have the proximity to all the mills," he says. "There are several companies like us and we're all competing with each other. For us, more material is a good thing. We have a pretty significant investment in the equipment that we have, so we've been able to draw material from more of a regional basis instead of a local basis. That's actually helping us stay efficient and recover some of those investment costs. The only problem we've had is feeding this great system."

The mills see the local processors as part of the team that is key to their successful use of recycled fibers as well. "It's hard for a mill to deal with changing supply when they're drawing in material from such a wide geographical area," Kahut says. "Some of the mills in the Northwest are pulling from California, Denver, Colorado, or Salt Lake City, Utah. Our local government is unique in the fact that they sit down with the mill and discuss issues with them. I don't think that the mills are having that same response from some of the other cities that they're pulling material from. They're facing some challenges from some of the other areas and they want to make sure that they don't have issues with their own hometowns."

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

MSW - November/December 2004