Wood recycling research gearing up at Calhoun Research Station

Todd F. Shupe, Nipper, W. Allen, Boethel, David J.  |  12/20/2007 2:16:03 AM

News Release Distributed 12/20/07

Two researchers have been added to the faculty at the LSU AgCenter’s Calhoun Research Station to develop environmentally friendly and economically viable products and methods to recycle decommissioned preservative-treated wood.

The researchers are working in two areas – engineering new wood products and chemically removing preservatives from decommissioned, preservative-treated wood – according to Dr. Todd Shupe, a researcher in the LSU AgCenter’s School of Renewable Natural Resources who initially developed the processes.

Dr. Cheng Piao, who joined station’s faculty in February 2007, specializes in recycling decommissioned preservative-treated wood into structural wood composites that can be widely used in outdoor industrial applications.

The other researcher, Dr. Hui Pan, started in October 2007. Her research at Calhoun will focus on recycling preservative-treated wood by chemical and hydrothermal methods. She also is working with recycled, preservative-free wood to develop high-value-added products, such as wood adhesives, chemicals and bio-fuels.

“We’re excited about launching a new research initiative in North Louisiana associated with forestry, our state’s major agricultural enterprise, said Dr. David Boethel, LSU AgCenter vice chancellor and director of the Louisiana Agricultural Experiment Station.

LSU AgCenter researchers have been developing the processes being refined at the Calhoun station for several years. Recycling treated wood products could save on disposal costs and liability concerns by keeping treated wood out of high-cost landfills, according to developers at the LSU AgCenter.

“Disposal of decommissioned preservative-treated wood has increasingly become a major concern because the popular disposal options – incineration or land filling – are becoming more costly and impractical,” Shupe said.

The researchers at Calhoun are mostly working with used utility poles that no longer are suitable for their original use.

Shupe said poles constitute a large part of wood going into landfills, so utility companies are interested in a systematic mechanism to dispose of them. The expense of sending poles to landfills is large – they must be properly handled and disposed.

“Disposal cost on a single pole can run as high as $80 to $100,” Shupe said.

Finding new uses for treated products is important to Louisiana because nearly half of the state’s southern yellow pine lumber production is treated with creosote, penta or chromated copper arsenate (CCA). Most material was treated with CCA before the industry voluntarily phased CCA out for consumer uses. Now, the three chemicals are largely used for industrial applications ranging from railroad cross ties and utility poles to highway and bridge guardrails.

The engineering aspect of the work, Shupe said, is focusing on refabricating used wood products into composite or laminated materials. In one project, Piao is working with Arnold Forest Products of Shreveport, which manufactures CCA-treated wood components for industry.

Arnold manufactures posts for highway guard rails and the wooden blocks that are attached between the metal rails and the wooden posts. The LSU AgCenter researchers are helping develop re-engineered components from recycled wood.

In one process, the scientists are investigating using sawdust from the recycling process to make wood-composite blocks. Although it’s difficult to fabricate thick panels or blocks by pressing sawdust and binding agents because of moisture and vapor pressure considerations, the researchers are looking at extrusion processes to create new products.

Along with using sawdust, the researchers also are creating new poles or utility pole cross arms by cutting decommissioned poles into pieces and using the smaller, suitable materials by laminating or gluing them to make new products.

“The old poles tend to have a lot of preservative in them – often enough residual preservatives to provide good protection for new products made from them,” Shupe said.

Piao also is working with Claiborne Electric Cooperative, which has utility lines at the Calhoun Research Station, to compare remanufactured, recycled utility poles’ performance with regular poles. And Dis-tran Wood Products in Pineville is helping evaluate recycled wood products remanufactured into cross arms for utility poles.

In a related project, Pan is working to refine a process called liquefaction – a method for recycling CCA-treated wood, which is ground and liquefied with an organic solvent that removes chemicals from wood products.

This process uses relatively low temperature, short reaction time and small amounts of organic reagents, Shupe said. The results can yield the chemicals originally used in the preservative as well as nontoxic liquefied wood that can be used for resins, molded wood products, foams and plastics.

A second process uses super critical water – water at high temperature under high pressure – that’s used to recover the preservatives and detoxify the wood for reuse. Shupe says research has shown this process can remove creosote from wood and yield a mixture of industrially useful hydrocarbons and other chemical compounds along with toxin-free wood.

“These processes can now remove 99 percent of all metals from sawdust,” Shupe said.

The process of liquefaction creates viscous globs of metals and viscous globs of wood, which can be formed into many products or used as a base for adhesives, Shupe said.

Both processes use wood that’s been ground fine, so they’re also appropriate for use with sawdust that results from Piao’s work with re-engineering treated wood.

“It’s a closed-loop system” Shupe said. “Both areas have to work together. Part of the process is engineering, and part is chemical.”

In the end, developing new engineered products requires separating used materials into reusable pieces and waste – decayed or damaged material. The waste, along with sawdust, provides the material that feeds Pan’s work.

“The research addresses creation of value-added products from materials that have become an emerging environmental problem,” Boethel said. “Our goal is to develop technologies for industrial use and hopefully lead to start-up companies. It appears our scientists already have begun to find industry cooperators.”

The research at the Calhoun Research Station is a cooperative project that includes faculty members from the LSU AgCenter and Louisiana Tech University. The work by the two universities is being done under the direction of the Louisiana Forest Products Development Center, located in the LSU AgCenter.

The forest products development center was created in 1992 through initial funding from the Louisiana Legislature to enhance the use of forest resources by working with Louisiana forest products industries to improve product efficiency, add value to products and become more competitive in the marketplace.

"The Calhoun Research Station, as one of the oldest research stations in Louisiana, has been the home to many successful research programs that have benefited not only the stakeholders of north central Louisiana but also the entire state,” said Allen Nipper, regional director of the LSU AgCenter’s North Central Region and resident director of the Calhoun Research Station.

“Wood recycling is an entirely new type of research effort at the station and has the potential to continue to place the station and the Calhoun area on the map as a location where innovative research leads to practical uses for Louisiana products,” he added.


Contact: Todd Shupe at (225) 578-6432 or tshupe@agcenter.lsu.edu
              David Boethel at (225) 578-4181 or dboethel@agcenter.lsu.edu
              Allen Nipper at (318) 644-2662 ext. 14 or anipper@agcenter.lsu.edu

Writer: Rick Bogren at (225) 578-5839 or rbogren@agcenter.lsu.edu

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