UPDATED 6/21/2012

Everyone knows the environmental benefits of recycling. Turning landfill-clogging debris into useful products is fundamental to green building. Yet recycling construction-site waste is a lot more complicated than recycling household trash.

The construction industry produces a lot of waste: 325 million tons every year, according to the Construction Materials Recycling Association, an industry trade group.

Residential construction is only a slice of the pie, but even the job site of one single-family home produces plenty of junk: scraps of lumber, vinyl siding, drywall, asphalt shingles, plastic film, PVC pipe, cardboard and paper, and bits of a variety of metals.

Recycling construction and demolition (C&D) debris is an appealing alternative to landfill disposal, and it’s promoted heavily in green-building rating systems such as LEED. I wondered how the system really works, how much of the potentially salvageable construction debris actually gets salvaged, and how recycling directly affects a builder’s bottom line.

To do so, I made five hypothetical piles of debris at the job site: gypsum wallboard, plastics, metal, wood and asphalt roof shingles. Then I looked at what recycling options are available for each. Here’s the first of those reports.

Drywall: Many potential uses

Gypsum wallboard, the first choice for walls and ceilings in new construction, is almost all (92%) calcium sulfate dihydrate, a natural mineral mined from ancient ocean floors. Paper facings account for another 7%, and impurities and additives the rest.

Roughly 15 million tons of new drywall are produced every year in the U.S., of which 12%, or 2.7 million tons (and possibly more), is discarded during installation as pieces are cut to fit. Those numbers may be somewhat lower these days given the health of the building industry; still, it’s a lot. The Michigan Department of Environmental Quality estimates that drywall adds up to 26% of all new home construction waste, or 1.5 tons for each 2,000-sq. ft. home.

Because the raw materials that go into new drywall are relatively benign (drywall from demolition is another story), it shouldn’t be that hard to find ways of recycling it. On paper, the list of potential uses is long. It can be ground up and used to make new drywall, used as a soil amendment, added to stucco, mixed with sludge as a bulk drying agent, mixed with animal waste to reduce odor, used in the production of cement, combined with wood shavings for animal bedding, and sprinkled on garage floors to soak up grease and oil.

The alternative is sending it to a landfill, which is what happens to a lot of it now. Landfill disposal of gypsum wallboard creates a variety of problems, but the one that public officials hear about most often is the smell. “Drywall doesn’t do well in a landfill environment,” says Randy McMullin of the Maine Department of Environmental Protection. It produces hydrogen sulfide gas, whose noxious, rotten-egg odor can be detected in minute concentrations by the human nose. In high concentrations, the gas is toxic. The finer the material is ground up, the worse the problem gets.

Recycling opportunities vary from state to state

Even though there are many potential uses for recycled drywall, recycling programs appear hit or miss. Some states have actively pushed the idea, others haven’t, and recycling can run into a host of practical and economic obstacles–everything from onerous licensing requirements to unpredictable resale markets.

One problem is the spotty availability of established processors. For example, there are 44 drywall pickup sites and/or processors in California, and an interactive web site where builders and consumers can learn more about them.

Massachusetts has a very aggressive construction debris recycling effort . Beginning on July 1, the state banned the disposal of drywall in landfills, the only state in the country to do so. There are a number of exemptions to these new rules, but the effect is to divert a high percentage of drywall scraps toward recycling and reprocessing. It took years for Massachusetts officials to work out the details with the construction and demolition industry, but the state says it now has a “sustainable recycling infrastructure” capable of recycling 80,000 tons of drywall waste a year.

At the other end of the spectrum, a phone call to the New York State Department of Environmental Conservation turned up the name of but one drywall processor in the state.

In Maine, the Department of Environmental Protection has a single processor to recommend, and estimates that only 5% to 10% of new drywall scrap is recycled. Vermont, a state without any processing plants of its own, reports about the same level of drywall recycling.

What if you worked in Texas? The state’s Natural Resources Conservation Commission assumes that most drywall scraps are taken to landfills. I was told wallboard scrap is not treated as a hazardous waste there and not covered by state regulations.

Texas maintains a searchable data base of companies that recycle a variety of construction and demolition waste, but it listed only five that specifically handle drywall. This is in the second largest state in the country with a land area equal to that of Burma.

And that seems to sum up this story of extremes, well-established efforts in some states, not much in others. In the end, says CMRA executive director William Turley, “very little” drywall actually gets recycled, mainly because the raw materials have little value in most parts of the country.

If you’re wondering what options are in your state, a place to start is with a state-by-state list of contacts maintained by Construction Materials Recycling Association’s companion drywall website. This is a list of people in state environmental offices who can direct you to a processor or a recycling center, should those services exist. Don’t be surprised if they don’t.

A recycling model from Europe

An important collaborator in the Massachusetts program is Gypsum Recycling America , a subsidiary of Gypsum Recycling International. The system developed by GSI was launched in Denmark in 2001 and now operates in seven countries, including the U.S.

Wallboard scrap is collected in dedicated 40-yard containers, emptied by specially designed collection trucks and taken to a warehouse. When enough has been collected, a mobile processor is brought in to reduce the waste to gypsum powder and shredded paper. The gypsum goes to a wallboard manufacturer and blended into new material; the paper can be used as animal bedding.

The company says it takes only a couple of hours to set up and break down the equipment, so a single processing truck can handle waste at a number of satellite storage areas. (For a look at how the process works, the company has posted You Tube video .

The company’s American subsidiary is located in Cambridge, Mass., and currently services New England while hoping to expand to a broader market. The Massachusetts Department of Environmental Protection approached GRI as it worked through details of the drywall landfill ban. GRI agreed to participate in the talks and eventually decided to set up operations in the U.S.

Another processor is USA Gypsum, , a Reinholds, PA, company that turns scrap drywall into gypsum powder that can be used in a variety of agricultural and industrial applications. About 90% of its output goes to agricultural end uses, not the manufacture of new wallboard.

The company processes between 20,000 and 22,000 tons a year, collecting drywall from an area bounded by Boston, Buffalo, N.Y., Pittsburgh and northern Virginia with three dedicated tractor-trailers and a number of independents.

Recycling can be cheaper for builders

Two obvious benefits to recycling are extending the life of existing landfills (while reducing the need for new ones) and diverting part of the C&D waste stream into the manufacture of new materials. For builders, a more immediate advantage is lower disposal costs.

Tipping fees vary by state, region and even by community, but they can be steep. In New York, for instance, fees for C&D debris range from $14 to $120 per ton, with averages between $40 and $60. In Maine, tipping fees are $65 to $85 per ton.

When recycling programs are in place, fees can drop significantly. A 2003 case study published by the Massachusetts DEP, for instance, says the lead contractor in a 2003 public school project trucked clean wallboard scrap to G-P Gypsum in Newington, NH, where it paid $2,559 in disposal costs. That was less than half the $5,450 it would have spent on landfill tipping fees. Overall, the contractor saved nearly $32,000 by recycling all of its construction debris, lowering disposal costs for the job by 75%.

USA Gypsum has a range of rates, but charges an average of $23 a ton, well below average C&D tipping fees in the Northeast. “We have to offer a financial incentive for people to sort the material,” says company president Terry Weaver.

Recycling is “facing some headwinds”

While this system can work, it sometimes breaks down. When I spoke with Buzz Surwilo in the Vermont Department of Environmental Conservation in early July, he told me G-P Gypsum had “closed the gates” to recycled drywall a few weeks earlier. Surwilo wasn’t sure why, or whether the closure was temporary or permanent. Requests for information from the plant have so far gone unanswered.

The upshot of the decision, Surwilo said, was to reduce Vermont’s 10% drywall recycling rate to zero, at least for now. “There a lot of kinks to be worked out,” he said.

Weaver points to one possible explanation: a drop in demand for new wallboard because of the housing slump, which in turn lowers the willingness of manufacturers to accept recycled wallboard, and a simultaneous increase in synthetic gypsum produced by scrubbers at coal-fired power plants.

In 2009, he said, power plants produced 18 million tons of synthetic gypsum (chemically identical to mined gypsum) but could get rid of only half of it. The result is a huge market surplus. In some cases, Weaver added, wallboard manufacturers have been able to get gypsum by paying only transportation costs, nothing for the actual raw material itself.

Also, Weaver said, drywall plants designed to run around the clock have had to cut back production, increasing plant inefficiencies and boosting the amount of waste wallboard they produce themselves. Weaver suspects some plants are now incapable of re-using all their own post-industrial waste, let alone in a position to buy more from the outside. “Recycling is facing some headwinds,” he said.

On-site recycling is an option

Another approach altogether is recycling drywall scraps on the job site, eliminating all transportation and tipping fees. Ground-up gypsum can be spread over the site, or mixed with soil and used for planting lawns and gardens.

A Texas company makes several versions of a machine it calls the Gyp Monster designed to turn scraps of clean drywall into a coarse powder that can be spread on site. The trailer-mounted machines, which sell for between $25,000 and $49,000, have a toothed head powered hydraulically by either a gasoline or diesel motor.

The company says the Gyp Monster can process between 4,000 and 8,000 lb. of scrap drywall per hour. Scraps are fed into a slot, either 36 in. or 60 in. wide, depending on the model. A built-in vacuum contains dust.

Company owner Jerry W. Petermann says the device is intended only for new scrap, not demolition. And while gypsum can be a useful soil amendment, it would be a good idea to check with local code officials to confirm the practice is permitted.

The Gyp Monster is small enough to be towed by a pickup to a job site, but companies offering specialized on-site recycling with larger equipment also may be available, depending on where you live. GBA’s technical director, Peter Yost, visited one such company in the Atlanta area and posted this report earlier.

The LEED connection

Builders hoping to win certification for new houses under the U.S. Green Building Council’s LEED for Homes program are likely to take advantage of a provision in the Materials Resource section offering up to three points for reducing construction waste.

Sarah Buffaloe, a USGBC specialist in this area, says this checkoff is common. She said the council is trying to steer processed wallboard away from landfills, where it has been used as an erosion-preventing cover, and back into the manufacturing stream. That might include not only the making of new wallboard, but a variety of other end uses.

That ground gypsum creates hydrogen sulfide gas was one consideration, she said, but not the main motivator. Making new products from processed wallboard is the best use, she said, adding, “Getting it out of landfills is the point.”

One factor in developing strong national programs, she adds, is the high cost of trucking C&D waste. That tends to make markets for reprocessed waste such as gypsum very local. Surpluses in some parts of the country may be offset by shortages in another.

Demo waste is another problem

Recycling clean drywall is a hugely complicated process, involving the intertwined interests of builders, manufacturers, regulators, processors and even power plant operators.

But the system essentially doesn’t exist for demolition wallboard.

Processors typically won’t take demo wallboard because of potential contamination from asbestos, lead or other toxic materials (Chinese wallboard? Forget it). Even when the wallboard is clean, builders may have to demonstrate it’s safe. For example, Nature’s Way Resources, one of the processing centers in Texas, accepts only new drywall, and only when a builder can produce a Materials Safety Data Sheet proving it contains no hazardous additives.

Given the uncertainties of recycling, Surwilo wonders whether the industry should focus on “looking upstream,” trying to reduce waste on the job site rather than find ways of dealing with it after the fact.

For now, there are a variety of public and private groups working on ways to improve the rate of drywall recycling. While there are some bright spots, there’s still a huge gulf between the potential and reality, and no clear path for bringing the two closer together.