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Highly mobile C&D processing equipment boosts profitability via cost-efficient material reduction, recycling, and onsite reuse.
By Carol Wasson
Contractors are changing the way they handle construction-and-demolition (C&D) debris. Less material is heading to the landfill, while more debris is being reduced, recycled, and often reused right on the job site. It’s a strategy made easier by highly mobile, specialized equipment that efficiently processes material—from site to site—at lower costs per ton.
Entrepreneurs are constantly creating new markets for recycled construction waste. Global commodity pressures are leading companies toward greater operational efficiency. There is less land that can be developed without significant demolition and excavation costs. On each project, waste disposal becomes a bigger factor. There is less available landfill space. Tipping fees are higher. Trucking costs are astronomical. At the same time, communities are resistant to new material processing facilities, and regulations make permitting difficult at best. Conveniently located sources for virgin aggregate or specification base materials are scarce. Material costs push upward, while tough competitors limit price increases. It’s a perfect economic storm that’s driving C&D debris handling in a new direction—use it or lose it. And having onsite processing capabilities means that more material can go right back into the job site for greater profitability.
C&D debris typically includes asphalt, concrete, masonry materials, soil, rock, wall coverings, drywall, plumbing fixtures, insulation, roofing, shingles, plate glass, wood, carpet, and electrical wires. Not surprisingly, asphalt, concrete, and brick account for up to 95% of all recycled C&D debris, according to recent estimates. Yet the recycling and onsite reuse of materials such as asphalt shingles and gypsum wallboard is increasing, as new markets and innovative processing methods come to the forefront.
Currently, approximately 11 million tons of asphalt shingles are disposed of in landfills every year. Yet there are markets for the material in hot mix asphalt, cold patch, aggregate road base, and new shingle production, and as a dust suppressant on rural roads.
Almost all scrap gypsum ends up in the landfill. The dissolved sulfate that results from this practice may cause odor, groundwater contamination problems, and risks to landfill workers if buildups of hydrogen sulfide gases should occur. The challenges associated with drywall recycling, say experts, include separating the paper from the gypsum and controlling dust during processing. Grinding systems fitted with screening systems and dust collectors have been developed to promote wallboard recycling.
Recycled drywall may be used as an ingredient in Portland cement, as a source of sulfur and calcium for agricultural land applications, and in the production of new drywall. It may also be used onsite as a soil amendment (in states where permitted).
On a recent commercial building project, a skid-steer with a bucket fed scrap gypsum into a portable, low-speed, high-torque grinder to produce a half-inch-minus product, which was screened before mixing it with the topsoil used on the job site. In this case, the paper did not have to be separated from the wallboard, as it would biodegrade in the ground. Note that some states do not allow this process, as the gypsum alters the pH of soil that may already be high in alkalinity.
Outsourced Recycling
Larry Beeler, owner of Busy Bee Landfill near Spokane, WA, recycles C&D debris with a DuraTech 3010 hammermill tub grinder to minimize the yardage being placed in the landfill he opened in the early 1990s. When changes in environmental regulations threatened the landfill’s viability for the disposal of demolition and construction inert waste, Beeler purchased the tub grinder and added recycling to his trade. “I wanted a grinder that would allow me to branch into additional markets,” Beeler says, explaining that his model will take on nearly anything he wants to feed it due to its large 10-foot tub and its heavy-duty hammermill.
Currently, 30% of Beeler’s business involves transporting the grinder from site to site and processing demolition woodwaste and greenwaste for land clearing and excavation contractors who wish to eliminate the transport of raw materials. Processed materials can be used onsite to prevent soil erosion or can be hauled off by manufacturing facilities for use as “hogged” fuel for boiler operation, or by livestock breeders for use as animal bedding.
Another major part of Beeler’s operation is the recycling of asphalt shingles. Roofers have their waste processed in his tub grinder at a fraction of the cost of dumping it at a municipal landfill. As a convenience, Beeler recently purchased a container truck and began a job site drop-off and pickup service. To meet regulations, containers are marked as “recycle only” and are removed when the job is complete. The shingles are processed at the landfill, and the ground material is sold for use in driveway and parking lot paving jobs. Beeler predicts that an increasing number of future road construction projects will combine shingle grindings with virgin aggregate in the asphalt mix.
Contract crusher RPEI of Peru, IN, is another contractor who specializes in recycled asphalt shingles. Much of its material is sold to counties for use as a dust suppressant on gravel roads. The company’s general manager says that most shingle recyclers are processing only about 25% of the shingles they receive. He also says that he’s not seeing that much of a market for its use in asphalt hot mixes. For that reason, RPEI is also offering its material to innovators who specify it for road sealants and roof sealants. New markets for shingle grindings may also include its use in making patio blocks, bricks, and sound deadeners, he says.
RPEI grinds its asphalt shingles in a 3680 Beast Recycler, a horizontal grinder manufactured by Bandit Industries. The unit was purchased because it could process the shingles in one pass, without the need for a screening plant onsite, says RPEI. The Beast Recycler is designed so that the heat generated during the grinding process does not adversely affect its operation. Other grinders, says the company, place grinding bits less than 3 inches away from the drum, allowing little opportunity for adequate air flow for cooling.
Multi-Material Processing
EJE Recycling & Disposal of Greenville, NC, processes “anything the wind might blow in” with its SSI Pri-Max shredder, a unit designed to reduce a very broad range of difficult materials without extensive presorting.
Needless to say, C&D debris is a mixed bag—particularly after a hurricane. A structure may be made of wood, but it houses appliances, furniture, carpeting, bed frames, mattresses, and plumbing fixtures.
EJE Recycling & Disposal purchased the SSI shredder to process mixed materials on the demolition or disaster site. While securing more contracts outside the recycling yard and landfill, the company would reduce transportation costs and maximize its landfill space and recycling output.
The company had looked at shredding systems rated from 50 to 100 tons per hour but found that this capacity applied to a limited range of materials. When processing the most challenging materials—mattresses, roofing, hydro poles, and cables—most units would slow to 30 tons per hour or would be unable to handle the material at all. They also needed a unit that would handle asbestos material without producing a lot of dust. Versus the performance of a high-speed grinder, the low-speed operation of the shredder produces little airborne debris.
EJE processes an average of 50 to 55 tons per hour of C&D material with its SSI Pri-Max shredder. It’s equipped with a mobile package, which allows EJE to pursue more custom work at remote customer sites.
Tackling Woodwaste Contaminants
A study conducted for the Clean Washington Center points to a grinding system that efficiently tackles the size reduction and contaminant removal required when processing post-consumer sources of woodwaste. The Contender Series from Universal Refiner Corp. features a “pan & disc” design that employs a cutting disc fitted with sharp teeth, rather than conventional hammers. After extensive field-testing, the Contender model is said to achieve a longitudinal fracturing of the raw urban wood in a way that frees a majority of the embedded materials (nails, screws, etc.) for subsequent removal via the use of magnets or other ancillary equipment. The end product is close to that of virgin wood chips, says the study. Also, the cutting action occurs deep within the machine, addressing the safety concerns associated with material that is ejected from standard tub grinders.
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Photo: DuraTech |
| A DuraTech 4012 industrial grinder processing tree debris |
Although termed as a portable, street legal, woodwaste grinder, Contender models are also applied to greenwaste, pallets, logging slash, stumps, railroad ties, and roofing shingles.
Getting Into Grinding
Jim Bresnick, owner of a small Massachusetts-based excavation company, knew that he needed to beef up his business when he noticed numbers of new competitors springing up in his market area. Adding another excavator to his fleet was a consideration, until he realized that he needed a way to truly differentiate himself from the rest of the pack. So he decided to start processing his own woodwaste onsite for each of his excavation projects.
Bresnick purchased a TCII-1564P HogZilla grinder, the most massive of four TC Series models designed by CW Manufacturing. He had tried out a smaller model on a rental basis over a six-month period and knew that he could keep the unit busy on a daily basis. Now he can complete his projects faster and more efficiently while cutting his disposal and transportation costs by grinding right into 100-yard trailers.
Marrs Tree Service of Kansas City got into grinding as well when its owner, Don Marrs, discovered he needed a place to go with all of the company’s tree debris. He bought a Vermeer HG6000 horizontal grinder and spun off a new company called Planet Marrs Recycling, a site that takes in about 5,000 cubic yards of material each year and is open to other tree services, landscapers, and excavators.
After the wood is unloaded—with a tipping fee of $4.65 per yard—the wood is processed through the grinder, using a 4-inch screen on the initial grind. The coarse brown mulch produced is stockpiled and aged for up to 10 months, with no turning. Then it’s re-ground with 2-inch screen and sold as a “double grind.”
Planet Marrs’ customers include local homeowners, wholesalers, retailers, landscapers, and nurseries, with the product ultimately ending up in commercial and residential products. The company’s 30-yard truck delivers the mulch, which retails from $22 to $31 per cubic yard.
Crushing on the Run
Rodman Companies, a large Dallas-based excavation company, purchased two Model 1040 IronWolf crusher attachments for its excavation projects. Although it’s not a milling machine, the company discovered that the unit works effectively at in-place asphalt and concrete recycling. Rod Vilhauer, the Rodman Companies’ co-founder, reports that the unit will produce material, which is usable onsite for fill, for approximately $1.00 to $1.50 per cubic yard. He stresses that even greater savings will accrue from eliminating the cost of trucking out unusable limestone and then subsequently hauling in fill material.
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Photo: Vermeer |
| Every year, Planet Marrs Recycling takes in approximately 5,000 cubic yards of material. |
Typically mounted on wheel loaders, the IronWolf Crusher is a heavy-duty equipment attachment designed for processing various types of rock, asphalt, and reinforced concrete. Powered by an auxiliary engine package mounted to the back of the loader, its crusher cutter drum comes in widths up to 10 feet.
The Option Is Yours
Best practices in C&D debris recovery include reducing waste at the source, reusing recycled products on the job site, marketing the remaining recovered materials, and using recycled content construction materials. In some cases, processing onsite makes the most sense. In others, it may be best to transport material to a material recovery facility.
The way one handles C&D debris will depend on many factors—the quantity of the debris, its material characteristics, the availability of space for onsite processing, the costs of offsite recovery, the existence of markets for the particular recycled materials, and whether one has the right processing technology for the job.
Construction-industry writer Carol Wasson owns JCL Marketing & Communications Inc.
GEC
- May/June 2006 |
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PHOTO: (large photo) VERMEER