Finishing last: shredding incoming material can help make an inert landfill operator the "last one standing" in a market region.

Operators of C&D landfills have one overriding reason to be interested in shredding incoming material: to extend the limited life of their profitable enterprise.

In many parts of the United States, opening a new landfill--even one accepting only C&D debris--has become an almost impossible task.

Thus, owners of existing landfills have a very real incentive to keep their gates open as long as possible, probably with the ability to charge more at that gate with each passing year.

Whether the shredding is done purely to increase the volume of material that can fit in the landfill or whether it is also a first step in seeking out recycling markets, operating a shredder on site is becoming standard operating procedure at inert landfills.

The same logic holds for steps leading to the landfill: at transfer stations or MRFs, at demolition and land clearing sites, and at saw mills and woodworking shops.

SHRED WHEN IT MAKES SENSE

At a C&D landfill in Conway, S.C., near Myrtle Beach, clean loads of yard waste, land clearing debris, clean scrap wood and asphalt shingles are all put through a grinder.

According to Jerry Johnstone, operations manager for the Horry County (S.C.) Solid Waste Authority, source-separated or otherwise relatively uniform incoming material is earmarked for the grinding operations area of the property when it arrives there.

"The wood waste we classify and separate into three categories: land clearing debris, yard waste and clean wood," says Johnstone, who adds that all three categories are run through the same 750-hp grinder manufactured by Continental Biomass Industries (CBI), Newton, N.H.

By weight, yard waste makes up the largest category, with Johnstone estimating that some 35,000 tons of yard waste arrives each year. "After we grind it, we probably get a 3 to 1 or even 4 to 1 volume reduction," he notes.

After it leaves the grinder, the yard waste material is placed into composting windrows where it slowly converts to marketable topsoil.

The highest value market comes from the land-clearing debris of recently felled trees, says Johnstone. "We grind it all and sell it for mulch," he remarks, adding that the process achieves a space volume reduction of "about 6 or 7 to 1."

To make a mulch product with a desirable 1-1/2-inch minus specification, this material is sent to a wood chipper made by Morbark, Winn., Mich., after it has passed through the CBI grinder.

In South Carolina with its long growing season, the mulch finds ready homes. "We sell every cent we produce," says Johnstone.

The county also receives scrap wood from a local flooring and joist company as well as pallets and other clean wood to the tune of about 2,000 tons per year, Johnstone estimates. That wood also passes through the CBI grinder but is then used internally on the county's property to provide traction on dirt truck paths.

The shreds produced from asphalt shingles are directed toward similar applications on the county's property. "We've used it on our main road to the landfill; the trucks compress the shreds until it's comparable to driving on asphalt pavement," says Johnstone.

The Solid Waste Authority, which won a CMRA Recycler of the Year award for 2005, has been so convinced of the wisdom of its shredding operation that it will soon take delivery of a more productive 1,050-hp grinder from CBI.

AN A-PEEL-ING IDEA

The Region of Peel, Ontario, is a fast-growing population center that is part of the greater Toronto metropolitan area.

Decision makers in the Regional Municipality of Peel have been confronting a rapidly growing solid waste and recycling stream in the past two decades.

Spurred on by both provincial recycling goals and practical cost-benefit reasons, the Region of Peel has begun collecting and processing not only traditional residential recyclables (bottles, cans and newspapers), but also materials such as yard waste and organic food scraps.

Faced with an array of such materials with a wide range of physical properties, the Region of Peel Waste Management Division has deployed two dual-shaft slow-speed shredders made by Vecoplan LLC, Archdale, N.C.

The Division's goal has been to put the yard waste and food scraps through a composting process that starts with achieving a uniform particle size thanks to the Vecoplan Hurricane 250 and VNZ 210 shredders.

"With our Vecoplans we get the best of both worlds, the right particle size for composting and a high level of tolerance for tramp metal or other foreign matter," says Larry Conrad of Peel's Waste Management Division.

The application is a difficult one, acknowledges Chris Hawn, director of business development for waste systems for Vecoplan. The slimy and slippery nature of infeed such as banana peels or whole oranges if fed through conventional screen grates can "turn it into something that looks like a Play-Doh factory," says Hawn. The systems in Peel have been set up with "special screens and fins that are adjustable to accommodate that kind of material," notes Hawn.

Mixed materials of a different nature can be encountered when slow-speed shredders are deployed at demolition sites.

Colorado Resource Management (CRM), Aspen, Colo., brings a Hammel New York Model 750 to demolition job sites throughout its operating region, according to a testimonial ad prepared on Hammel's behalf. CRM's George McDonald says the machine reduces a variety of materials to a 1-1/2-inch-minus size, dramatically saving on hauling costs when that material is being landfilled.

But the company has also found lucrative recycling markets for many materials, with McDonald estimating that CRM recycles at two-thirds of the job sites where it brings in its Hammel shredder.

ON THE SPOT

Large-scale generators of materials such as scrap lumber can also have very sound balance sheet reasons to cut their waste materials down to size.

According to Vikki Van Dam of shredder manufacturer Weima America Inc., Fort Mill, S.C., "I don't think marketing material is the reason many of these generators buy a shredder, but it's a bonus." She adds, "When they see how much they are spending on waste and material handling, the justification for a shredder becomes more clear."

In the case of clean wood scrap generated at sawmills or cabinet manufacturing plants, there is almost always an alternative to disposal. "Some companies shred their waste for boiler fuel while others sell it for landscape mulch or animal bedding," says Van Dam.

The volume reduction in such applications can vary. Van Dam says that while wood block scraps may only be reduced at a 3:1 volume ratio, large skeleton boards with shapes already removed can be shredded for an 8:1 or greater volume reduction.

Entrepreneur John Dorscht, Windsor, Ontario, Canada, created the SchredMax line of machines that is now part of the PriMax line offered by Shredding Systems Inc. (SSI), Wilsonville, Ore. He says that in addition to landfill owners, transfer station operators, and demolition contractors are natural beneficiaries of shredding for volume reduction.

"Primary reduction makes the initial sizing step and takes the bad stuff out; the stuff you want to keep goes for secondary processing," Dorscht remarks.

The author is editor of Construction & Demolition Recycling magazine and can be contacted at [e-mail].