By weight, the most significant portion of a construction and demolition materials stream is almost always made up of metal, wood and aggregates such as concrete, asphalt or brick. After separating and processing these materials into new products, recyclers of construction and demolition materials report that end markets are relatively easy to find.
While the plastics portion of a mixed C&D materials stream may be insignificant in terms of weight, the volume occupied by plastics material also is difficult for recyclers to ignore.
“When you look at it by weight, it’s easy to turn a blind eye to plastic, because there is not that much of it,” says Matt Heaton, general manager of Evergreen Recycling, a Las Vegas-based company that recycles C&D materials as well as commercially generated recyclables. “But when you look at our operations and what we’re doing and the volume of space that the plastics take up, you are going to have to deal with it whether you like it or not, because it is everywhere.”
Historically, Heaton says that many C&D recyclers operated like transfer stations, in that they recovered construction and demolition materials that were easily separated and for which they had end markets. The remaining material, including plastics, was sent to a landfill.
As downstream separation technology advanced, C&D recyclers began hand picking plastic from their C&D material streams often because it caused particular hassles to their downstream sorting technology, particularly with plastic film or tarps. Recently, however, in light of the increased attention being paid to sustainability, and specifically to LEED (Leadership in Energy and Environmental Design) certification standards, recyclers of construction and demolition materials are not only separating and recovering plastics from their material streams, but they are actively pursuing a demand for their plastic products.
THE PLASTICS PROCESS
Recyclers indicate that there are several types of plastic materials produced by construction and demolition activities. The most common materials are plastic film, plastic buckets, corrugated pipe, rolled pipe and vinyl siding, according to Terry Gillis, general manager of Tacoma, Wash.-based Recovery1.
While recyclers have begun developing a number of end markets for plastics derived from the construction and demolition materials stream, some of these plastics still pose problems when introduced into a system that incorporates mechanical separation.
“I see film plastic as the biggest troublemaker,” says Jay Edmonds, sales engineer for Krause Manufacturing, Bellingham, Wash. “It is large enough and flexible enough to blind screens and trommels. It can wrap on disc screens, trommels, finger screens and head pulleys when making a right-angle turn. Also, its bulk/length may cause it to be stretched the entire distance of the sort line and still not be off the infeed belt.”
Because of the difficulties plastics can cause for a downstream separation system, they are frequently manually separated from the material stream before they are mechanically processed, if they are at all.
“Much of it is extremely large,” says Gillis of the plastic material that enters his facility. “Sheets can be 50 feet by 50 feet and pipes can be 24 inches in diameter by 10 to 20 feet long.” He adds, “Most of the plastic is extracted with excavators before the sort line, but some is extracted off the sort line.”
Cal King, general manager of Chicago-based Recycling Systems Inc. (RSI), a recycler of commercial and C&D materials, says personnel at his facility are asked to look for plastics at the initial point of sorting. “They separate out the recyclable plastics such as milk and pop crates and large drums from those that are unsalvageable,” he says.
For many C&D recyclers, hand-pick stations may serve as the only means of sorting for plastics materials, while mechanical equipment may be used to process and prepare the plastics for sale into their end markets.
“As far as plastics sorting goes, it’s primarily all by hand,” Heaton says. “We use screens for fine grain separation and then we bale and granulate some materials,” he adds.
After C&D recyclers have separated, sorted and/or processed the plastics coming into their facilities, they can turn their attention toward finding a demand for the recovered plastic grades.
Several factors may affect whether C&D recyclers are able to sell loads of recovered plastics to secondary processors or into end markets. These factors involve the type of plastic, contamination levels, facility location and price.
Recyclers indicate that HDPE (high-density polyethylene), LDPE (low-density polyethylene) and PVC (polyvinyl chloride) are the easiest grades of plastic to find markets for, though PVC can pose difficulties if it has already been installed in a plumbing system. “We can find a market for cuttings from PVC installations. I can get PVC recycled, but if it’s ever been installed or there is any question that it might have been installed, because of its common use with sewer line, it’s essentially impossible to sell it,” says Heaton.
RSI’s King says HDPE is the easiest to hand pick and consolidate into a saleable load to be used in the production of plastic lumber or as a cell liner for landfills. “Although there is a large volume of other types of plastic, their contaminated condition, labels and markings make them unsaleable to our end markets,” he says of most other plastics.
Because of the rugged conditions present in a construction and demolition environment, at times the plastic recovered by recyclers is so contaminated that it is difficult to find markets for some materials. “There is really no reasonable end market in Minnesota for plastics,” says Jason Haus of Dem-Con Cos., a C&D recycler based in Shakopee, Minn. “We have a couple of outlets, but the material must be extremely clean and like new, otherwise it will be rejected. Any dirt on the material would cause rejection and the only way to supply that type of [consuming] facility would be source separation, which has always been a challenge in our marketplace.”
While Haus points to difficulty in finding end markets in the Midwest, on the West Coast, Heaton has found a California secondary processor that will accept mixed-plastic loads, even though the material is not clean.
“The real answer to how much you need to clean it up; it’s a matter of specification to your buyer,” says Heaton. He provides this example: “Where I am, I might have a product that would sell for $100 per ton if it was cleaned up beyond the point that I’m capable of cleaning it up. I can turn around and sell that product for $40 per ton and it will be accepted and at some other point in the transportation process it will be cleaned up.”
Heaton says his location near the Pacific coast may give him an advantage as he sells flexible and rigid mixed loads of plastic as source material to a secondary processor in California, who ultimately exports the cleaned plastic materials.
“It’s rare that you find secondary processing occurring with the U.S. with our labor rates,” Heaton notes. “That’s something that has occurred since the market crash. I’m finding a lot more willingness out of the domestic markets. I believe that’s ultimately because we had so many middlemen working in the equation that the ultimate end consumers were in the U.S. more than we realized, and they lost their material streams when everything went screwy, for lack of a better term.”
A final factor that may affect markets for recovered plastic is the price for material that C&D recyclers can attract from buyers. “When the dollar value is higher for the recycled plastics, it has a much greater effect on how much is pulled from the materials stream,” says Tim Griffing, system engineer for Continental Biomass Industries Inc., Newton, N.H. “When the value is low like it has been in the last year, the initiative for pulling these plastics is also low. Recovery is driven by the market and what [recyclers] can retrieve for baling it.”
While Griffing indicates that price is the most important determinant as to whether plastics are recycled, that may not be the case for long. With the emerging trend of construction projects seeking to meet LEED (Leadership in Energy and Environmental Design) certification building standards, more attention is being paid to using recycled-content building materials and recycling all materials resulting from construction activities, including plastics.
“Although plastic is still a small percent of the materials we recycle, it has been increasing,” says King. “At our facility in only the last two years, our plastic recycling has increased by 250 percent. The USGBC (United States Green Building Council) LEED initiative has made plastic recovery economically viable for us and has forced the industry to increase and improve the plastics recovery infrastructure.”
As technology continues to develop and contractors adopt more sustainable business practices that support recycling and the use of recycled-content materials, Heaton is optimistic that recyclers of C&D material will continue to derive more value from their plastics material as they put more effort into finding end markets. “I think you could chase LEED certification and not recycle plastic but you’d be explaining it forever,” he says. “If you have to apply labor to something to clean it out of your stream, you have to at least look for a market for it, because you are already putting the sort labor on it.”