GAINESVILLE, Fla. --- Roofing shingles, gypsum board and concrete blocks could join newsprint, milk jugs and aluminum cans in the recycling bin and may help the construction industry save money in the process, say researchers at the University of Florida.

Timothy Townsend, professor of environmental engineering, and his student assistants hope to show contractors, consumers and state officials how to save money by putting useful construction wastes back to work rather than dumping them into landfills, where they are likely to contaminate groundwater as they break down.

Florescent light bulbs, for instance, contain mercury, as do thermostats and certain types of wall switches. Roof vent flashing contains lead.

"Construction and demolition waste, or C&D, has an environmental impact," said Townsend. "C&D wastes account for 23 percent by mass of the solid wastes in Florida and are now recognized as a source of groundwater contamination."

But making the program succeed may depend more, at least in the beginning, on making it financially attractive rather than on touting its environmental benefits.

"We know that recycling C&D will save money that can also be passed on to consumers in lower construction costs," Townsend said. "But separating the material at the construction site, rather than shipping it to a materials recovery facility, reduces the likelihood that recyclable material will end up at the landfill.

"Recycling has become more important and potentially cheaper than putting C&D in landfills since the cost of using landfills has risen," he said. "Several Florida counties have even made it illegal to put C&D waste in landfills that do not have liners."

Since February, Townsend and his students have been scrounging around construction sites in Alachua County, some in the shadow of the UF campus, separating all manner of debris at residential and commercial construction and demolition sites to see what is still useful.

They also are experimenting in the laboratory to determine over time what happens to C&D debris that ends up in landfills. Townsend simulates landfills by placing waste building materials in 7-foot-high metal cylinders and regularly testing the "fermentation" -- the odors and gasses they produce. Computerized tests confirm high amounts of sulfides and high acidity. The "nose test" also confirms the presence of sulphur.

Townsend said state environmental policy makers are striving to reach a balance between environmental protection and increased regulations and costs for C&D waste disposal. Indeed, the state Department of Environmental Protection (DEP) is working with Townsend and his team on the project and hopes to see it succeed.

"We're very excited about it. We feel that, yes, we're headed in the right direction," said Tom Edwards, an environmental specialist with DEP and contact manager with the UF project. "C&D is very hard to recycle. We tend to see it as solid waste, not a recoverable material."

Edwards and his department are helping Townsend get out the word to contractors and others in the construction and demolition industries. A workshop on changing state regulations on C&D waste was held in Tampa last month, and three more are planned during the next several months in other parts of the state.

The study is scheduled to be finished by March. Until then, Townsend and his students will keep digging through building site throw-aways in hopes of making demolition and construction a little more earth-friendly.

"No one wants to live near a landfill, and no one wants the water table contaminated," Townsend said. "So it behooves us to recycle and to develop new markets for recyclable materials."

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• Recycling and Waste
• Environmental Issues
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• Hazardous waste
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