Innovators inside and outside the solid waste industry are developing strategies for handling C&D. With landfill space tightening and many sites being closed to C&D, recycling and making better use of existing equipment provide functional economic alternatives.

By Penelope Grenoble O’Malley

In Michigan, a real estate developer gets fed up with hauling land-clearing waste to landfills. In Virginia, an underground utility construction company decides it can make a profit recycling asphalt and concrete, and this leads to large-scale processing of mixed C&D (construction and demolition waste). In Florida, a hurricane victim buys himself a grinder and sets up shop. In Albany, NY, a landfill manager installs a heavy-duty grinder on his working face to increase productivity and make better use of tight space.

What all these operations have in common is a willingness to innovate.

From ADC to Designer Mulch
Real estate developer Larry Mullins bought his first grinder in 2000 and started out selling recycled landscape debris to local landfills for alternative daily cover. Today Environmental Wood Solutions Inc., headquartered in Orion, MI, does 50,000 pounds of decorative landscape mulch a year, 500 to 600 tons of compost a day, and processes as many as 100,000 railroad ties annually, which makes the company one of the largest wood fuel suppliers to the state’s co-generation power industry. In all, Mullins’s operation includes a contracting company that does the land clearing and site prep on property he intends to develop, the composting division that recycles waste from municipalities throughout southeastern Michigan, a 10-acre industrial wood-grinding facility that includes dye operations for coloring mulch, plus another 285-acre processing yard and a second onsite grinding division. Mullins maintains 14 130-yard walking floor trailers to deliver product to clients, and his own fleet of trucks to collect what he recycles.

“We created a lot of markets,” says Mullins. “There was a need and nobody was filling it.” Environmental Wood Solutions currently owns four grinders, a Vermeer TG 9000 tub grinder, a Morbark 7600 and 5600—both 1,000-horsepower horizontal grinders, and a Morebark 1400 self-loading tub grinder.

“The reason we went with a 5600 and a 7600 versus two 7600s or two 5600s,” Mullins continues, “is that we use the 5600 for grinding dense material like logs for our hardwood mulch. The 5600 has the same horsepower as the 7600 but a smaller surface area on the mill, which keeps us from feeding too much at a time. We use the 7600 for big brush piles, and we put all our pallets and construction debris through the 7600 because it has a large opening, which means you’re not always jamming up trying to get material into the mill. To feed the grinders we have two 350 Fuchs material handlers with a 50-foot reach and hydraulic elevating cabs. We use the 1400 Morbark for smaller onsite jobs, say 2000 yards; it’s more cost-efficient because we don’t have to bring in a second piece of equipment to load the tub.

“We sort the different types of wood as it comes in. The kiln-dried industrial waste wood has a higher and better use than fuel and we use it for our landscaping materials. Some of the material is processed twice. Logs, for example, go through a horizontal grinder and then are reground back through a tub.”

Mullins says the Vermeer TG 9000 tub grinder is used to increase production in the yard, but since it’s a portable, it’s also used for onsite processing jobs in locations where space isn’t limited. Equipped with a 1.5-inch screen, the Vermeer is also useful for regrinding large volumes of material. The company has just built two new 15,000-square foot maintenance facilities to service its four excavators (one John Deere and three Caterpillar), four loaders, two John Deere dozers, three Timberjack skidders, and two Caterpillar track loaders.

PHOTO: Bandit Industries

Bandit's 3680 Beast Recycler.

At Vermeer, Mike Byram, senior director for the company’s environmental business segment in Pella, IA, applauds Mullins’s commitment to maintenance. “Both maintenance and cleanliness are important,” says Byram. “You can get material built up in your machine that can cause bearings to run hot, which can lead to increased wear and reduced performance. People who do a good job maintaining their equipment clean it at least on a daily basis. They move the machines around because all machines build up material underneath, and they make sure that bearings and pivot joins are cleaned and greased. Grinders are high wear. You’re sliding and grinding material against them all day. If you don’t replace things like cutters and other wear items at appropriate intervals, you’ll be eating into the support material for that item and, at that point, the equipment will be costly and difficult to repair.”

Grappling with the Big Stuff
“You’ve got to remember that everything around you is dirty,” says Robby Gill, general manager of Cloverdale Fuel Co. in Langley, BC, “and you have to be sure that everything you’re working with is maintained properly.” The company decreases wear and tear by presorting and pre-splitting material before it hits the grinder. “A lot of what we process is really huge and massive like old growth stumps,” says Gill. “Not only does splitting help us to make sure the material is the right size but we spot metal or rock that might be in the loads.” The company operates a TCII-1564P, 1,000-horsepower Hogzilla tub grinder from CW Mill Equipment Inc. in Sabetha, KS, which features a torque converter instead of a clutch. Gill uses a grapple to sort or, alternately, an excavator with a shear to split large pieces. The major market for the end product is temporary road construction. “Hog fuel is cheaper than a gravel road and it can be taken away with organics afterward,” says Gill.

“Another important operating consideration is to make sure you run the proper screens in the right hammer configurations. With just straight trim box you can maybe get away using a more fixed hammer set, but if you’re running something that’s not as forgiving, you’re better off running a bigger screen size—and make sure the hammers are fixed.”

Dan McAuliffe specializes in recycling houses in the rapidly developing area around Snohomish, WA where he estimates on average he processes a house a day. McAuliffe recovers copper and aluminum, cardboard, concrete, brick, blocks, and asphalt, as well as wood, which he processes with a 1564 Hogzilla, and he says the secret is to screen out contaminants right at the beginning. “From there you can start to separate with magnetic separators, shaker screens, then picking belts. We do probably 50% machine-, 50% hand-sorting, and our recovery rate is about 9%.

“Ideally for this application we should be running a horizontal grinder because it would be a little tamer. But I don’t like restrictions. And a horizontal grinder can restrict your operation. If you throw in an 8-foot stump, the machine won’t like it. The other thing is you need the right size loader to feed the grinder. We use a bucket and thumb because grapples are a hindrance if you’re trying to pick up something like a piece of rebar. With a bucket and thumb you can also build a road base if you’re out in the field or dig a ditch to drain the site.” Versatility and reliability are the name of the game for McAuliffe, whose yard is open round the clock. He’s sold on the Hogzilla’s torque converter over clutch machines and he’s also sold on the fact that he can use generic parts on the Hogzilla, which increases availability, which decreases downtime.

Sort Before Grinding
If ever Raul Del Portillo—vice president of Environmental Processing Systems Inc. in Coral Cables, FL—needed to be convinced about the importance of presorting, a stint in 1998 grinding debris in Puerto Rico after Hurricane George did the trick. Del Portillo owns two Diamond Z grinders, a 1463, which he uses to process larger chunks of wood and a self-loading 1460 that he uses for green waste and landscaping debris. From the 1,000 yards to 1,500 yards of debris he takes in daily he turns out boiler fuel, compost, and mulch. Nothing gets landfilled.

PHOTO: West Salem Machinery

“Hurricane debris comes completely contaminated. It comes with steel and rebar and rock and concrete. In the job we did in Puerto Rico, over 20,000 tires came out of the pile. We handled 300,000 cubic yards of material, most of it picked up off the roadside. Another problem was that everything was coated with mud and dirt. What you thought was a piece of wood might be a steel beam. When we started, the waste stream was full of contaminants, which not only damage your machines but ruin your products. I went to Puerto Rico with a container filled with $100,000 worth of parts that were supposed to last the entire job. In a week and a half I was out.

“Through a process the government calls cost value analysis, we convinced the Army Corps of Engineers that we had to separate the material before it went to one of the five grinders we had operating. We set up a large trommeling system with picking stations. We had Al-jon metal compactors working fulltime and over 40 hand-pickers, and this was just at one of two sites we had operating. We also had what we called temporary staging stations and we moved the grinders from one place to another. We were there for 10 months. By sorting the material before we processed it, we ended up saving the government $1.5 million, and the farmers had a clean, useable product to use on their fields.”

Lessons learned from processing Puerto Rico’s hurricane debris? “You have to have a commitment to have things done properly. I have a policy in our yard that we have no metal on the ground. I’ve discovered if there’s a piece of metal next to a container that’s one block away from the grinder, somehow within a week by itself that piece of metal will mysteriously appear inside the wood pile and will be ground. If I have a clean wood pile and a pile with dirt and wood next to it, I require at least two widths of a loader between the piles. Excessive? Yes, but I can guarantee that if you maintain only one and a half widths, two days from now it’s going to be one width, and a week from now both piles are going to be mingled together.”

Making the Grade
At Phoenix Recycling in Des Moines, IA, mingling debris is not the issue, getting the right mix of C&D to turn out a marketable product is. According to vice president of marketing Rob Hosier, alternative daily cover is the name of the game, processed from approximately 200 tons of mixed C&D the facility takes in daily. The debris stream goes through a rough sort on the floor, then through an integrated system to be separated into three different gradations. Hand-sorting removes wood, metal, concrete, plastic, and contaminants like fiberglass. “We’re not necessarily trying to pick out everything because we need a certain amount of fiber and organics to mix with the dirt to make a superior product,” says Hosier. “What’s left, about 10% of what we started with, goes to the landfill.” Phoenix uses a vertical grinder from West Salem Machinery in Salem, OR, to produce its ADC. “This machine will take metal,” says Hosier, “some of which we grind intentionally, and concrete, usually 50-pound blocks or less, along with brick and lumber that’s less than eight feet long. With it we do about 40 to 50 tons an hour. The specs for the ADC are established by the Construction Materials Recycling Association, and they change constantly. The idea is to get a mix of sulfates and organics that will be accepted nationwide. Our biggest challenge has been with throughput—to get the system to do more volume and handle more inconsistencies in the feed stock so they don’t reflect in the ADC.”

Mark Lyman, president of West Salem Machinery, describes the rationale behind Hosier’s grinder. “The way our machine is set up we have different types of tooling we can mount, depending on the type of material a customer might be running. At Phoenix, they’re not doing a lot of sorting, so we have a more contaminated fraction going into the grinder. Because of this we put in swing hammers, which, because they swing, will lay back. That way, if they get something that doesn’t want to be ground, the hammer can actually fold back or lay back out of the way, providing the opportunity for that piece to clear the machine.

“Even with these kinds of safeguards people make mistakes. They don’t design in the right clearances so they don’t have enough vertical drop into the grinder, for example. You need to be careful that you allow space for long material to turn and fall into the grinder so it doesn’t jam up the infeed. Another critical consideration is the clearance from the grinder to the discharge conveyor. Sometimes people put the discharge conveyor too close to the bottom of the grinder, which can be a problem because this grinder can handle such large volumes you need to allow enough space for the material it produces. If the discharge conveyor is coupled too close to the grinder, you can have problems with material building up.”

Getting it Down to Landfill Size
For landfills that receive waste that has not been reduced in volume, there is the option of the Diamond Z SWG 1600, 1,650 horsepower, with the industry’s largest hammermill system at 15,000 pounds plus. Joe Giebelhaus, solid waste manager for the City of Albany, NY, Department of General Services, bought one of these new tub grinders and set it up on his working face. “We tried the idea out conceptually with a much smaller machine, and that was successful enough that we decided that, instead of processing 50% of the 1,050 tons of combined MSW and C&D we take in a day, we wanted it to be 100%. So we bought the 1600.

“It’s basically a big tub grinder on tracks,” says Giebelhaus. “What makes it work so well is process speed. There’s been a shift lately toward slow-speed, high-torque machines, but Diamond Z went the old-fashioned method of high speed. The older machines would more or less pull the material apart whereas the high-speed ones beat it into submission.” Giebelhaus’s 1600 is fed using an excavator equipped with a clamshell grapple attachment. Some sorting is done to eliminate material that doesn’t rip.

“At a traditional landfill, the trucks offload, and the dozers and compactors push the trash and shape it and compact it. Here, we have the trucks dump it on the working face and the dozer more or less pushes it into a pile for the excavator,” says Giebelhaus. “The excavator grabs it and puts it in the tub. The grinder processes it through the mill and out the conveyor belt to a compactor on the backside.”

Landfill space was the rationale for purchasing the machine. Only 10 acres of the 100-acre site are currently open. “For every three months we grind,” says Giebelhaus, “we pick up one month of capacity. The machine paid for itself in one quarter.” But Giebelhuas counsels that making something this novel work requires buy-in from everyone in the chain of command, “from the top executive to the guy loading the grinder. They have to believe in it because we’re writing the book here every day.”

If a grinder on the working face seems too radical, one alternative for maximizing space is better compaction. Two things are different about the Trashmaster compactor from Terex Roadbuilding in Oklahoma City, OK, according to Eric Speck, the company’s manager of landfill compaction. (The machine was originally developed by Rexworks, which was bought by CMI, which was bought by Terex). “The main thing,” says Speck, “is the pressure on the ground, which is what provides the compaction. We have narrower wheels than any machine in the industry, 40-inch wheels on the back and 35-inch on the front of our 390 model. The competitive machines in this class all have wheels that are 48 to 55 inches wide. The stance of the wheels is also different. The front two wheels are narrow, almost touching each other, while the rear wheels are spread outside of both front wheels, so when you make a pass, material under the full width of the machine is being compacted. A third thing is the cleat design. The triangular cleat design provides good chopping action to break up the debris in the landfill, which is especially helpful with C&D. One cleat does all of it; you don’t have to change when you’re switching from MSW to C&D.”

“We recently sent a Trashmaster on a demo to a landfill that was running Al-jon machines,” says Mark Hyatt, general manager of Road Machinery Services Inc. in Statesville, NC. “Our 390 sank 2 feet deep, and it took four machines to pull it out. The problem was this ultra high-density machine was walking onto trash that had been compacted by low-density machines. By the end of the week, our machine had brought the compaction level to where it could work on it and they were actually backing their dump trucks over trash the 390 compacted.”

Roads to Success
Challenges associated with landfilling road demolition waste is part of what got an underground utility construction company in Chesapeake, VA, into processing C&D. The company does $20 million in water, sewer, and storm drain construction a year. Eight years ago, when it was installing a sewer on a barrier island that was far removed from any convenient supply of natural aggregate, the company bought a small mobile crushing unit and convinced the city of Virginia Beach to approve re-crushed asphalt, torn up during construction, as a new pavement base. Even though production with this first machine was limited, the company liked what it saw and, in June 2000, began operating a state-of-the-art concrete and asphalt recycling plant that today generates nearly 40,000 tons of recycled concrete and asphalt a month. It uses some of the material itself and sells the rest.

“The operation has a twofold advantage,” says Jimmy Sisson, chief operating officer of Waterway Recycling LLC. “The construction community has an outlet to dispose of clean concrete and asphalt debris at no charge and we sell a high value, 1.5 inch minus crush-and-run equivalent for roadways and parking lots. And it keeps the material out of landfills.”

The initial recycling venture went so well that in 2001 the company embarked on a plan to build and operate a bulk mixed C&D recycling facility. Designed in consultation with Netherlands-based Waltec Practical Waste Solutions, and installed and with some parts built by Machinex Industries Inc. in Plessisville, QC, the plant has the capacity to handle approximately 700,000 tons of C&D debris annually. Plans are for the waste stream to come by barge from municipalities along the eastern seaboard, and an initial contract is in the works to process C&D debris collected in Staten Island, NY. “It’s a very simple equation and it’s an ancient mode of transportation,” says Sisson. “And we’re convinced we can be competitive with it.”

Waterway Two-Step
According to Waltech’s Dirk van der Wal, there are two keys to the system Waterway Recycling has installed—European components, including European grinders that van der Wal says are more pulverizing than American-made grinders, which tend to “break and grip”; and the unorthodox placement of human sorters. “I told them to turn around the conventional model. Accept that separation with machines may not be 100% and then correct it with people. In the United States you see a lot of sorting that involves people grabbing from the line what they want. In this system, what they take from the conveyors is material they don’t want. At the Virginia site, the sorters are located behind the machines and only remove what the machines miss. The final product remains on the belt.

“There are three important measuring points in the processing of C&D materials,” says van der Wal, “the quality of the final product, processing capacity, and expenses—which include investment, utilities, and staff. It’s logical to want a wooden pallet or door to be as large a piece as possible when getting it off the sorting conveyor. But the larger the pieces the less efficient the sieves, air technique, magnets, etc., will be. What you get with the kind of a system that Waterway Recycling installed is very high separation return, very large processing capacity, relatively few sorting personnel, and a high-quality final product.”

The Waterway Recycling facility uses dual lines that are the mirror image of each other. “We start with a hydraulic-over-electric, low-speed, high-torque grinder from Rentec,” says Sisson, “which takes everything we put into it and reduces it to a 2-foot minus material. This drops through the bottom of the grinder onto a lift conveyor, which takes it up past our picking station where two men are looking for wire, cable, and textiles. From there the material passes through a high-speed star screen (built by Machinex to Waltec’s specs) and everything 1.5-inch minus drops out at that point—mostly dirt, with some wood and plastic chips, and occasionally some asphalt shingle pieces. The state has approved this as ADC, which is critical because it makes up a large volume of our debris stream.

“Bricks and masonry blocks cross the star screen, then go through an air separation system, which is a combination of forced air and vacuum-assist that takes light fraction out of the debris stream—film, light plastics, any paper products—from there it’s routed into a compactor and delivered to a waste-to-energy facility as high Btu boiler fuel.

“Past the air separator,” Sisson explains, “the cleaner bulk product drops into a water separation system (designed and built by Waltec), which is basically float-sink, and all the metals, all the brick and masonry block material drop to the bottom and go in a separate direction. All of the wood—along with some of the other things we don’t necessarily want that may still be attached to the wood—float off the end and head up across a picking station where we do quality control—picking out everything that isn’t wood, including plastic, sheet rock, and paper. The wood stream drops into a West Salem high-speed wood grinder and we end up with a half-inch clean product that we sell for boiler fuel and raw material for recycled wood mulch.

“The brick and metals, both ferrous and non-ferrous, and the block material go across another picking station where magnets remove the ferrous metals. We handpick the nonferrous metals as high-value easily recoverables, while the brick and block material goes off the end of the conveyor and we sell it to our concrete and asphalt recycling company, which crushes it into saleable material. We sell the ferrous metal and give away the recovered fine material. Once we begin receiving debris via barge, we will be looking toward running two shifts plus a maintenance shift that will process and recycle nearly 2,400 tons a day.”

“It’s a large system,” says van der Wal, “but it’s very simple and very simple to maintain. And it was built to be flexible. You can run large capacities with very few people, and you can quickly adjust it as a function of your markets.”

Journalist Penelope Grenoble O’Malley is a frequent contributor to environmental publications.

MSW - July/August 2005