May 2006

 

Growing amounts of wood waste

With new buildings going up and old buildings coming down at a record pace across the country – generating tons of construction-and-demolition debris – it is easy to make the assumption that wood waste is a growing segment within the waste industry.

New construction hit a record of $1.185 trillion in February, according to the United States Commerce Department. Construction spending grew 0.8 percent over January and by 7.4 percent over February last year. Non-residential construction increased 9.6 percent. Residential construction jumped 7.1 percent. Public construction gained 6 percent.

Where is all the wood waste from these construction projects going? Finding numbers to back up the assumption that wood waste is growing is not easy. No government agency or trade group regularly tracks wood waste. Those that do track C&D debris, consisting of steel to concrete debris, do not break out wood waste separately.

Houston-based LETCO Group L.P., which operates facilities throughout Texas, processes a small amount of wood waste from construction. Mark Rose, area president, said wood waste is processed into fuel and is usually burned by paper mills.

“I cannot say that volume is up,” Rose said. Construction in the Dallas and Houston markets has been strong for a long time, he said. “Wood waste is very regional due to a very low sales price and high transportation costs,” Rose said.

LETCO, which recycles mostly tree trimmings, grass clippings and leaves, is a subsidiary of Fort Lauderdale, Florida-based Republic Services Inc. The solid-waste company, which serves markets in 21 states, does not break out the results for its subsidiaries like LETCO. Republic Services also does not reveal C&D amounts.

It is a similar story at Houston-based Waste Management Services (WM), the country’s largest solid-waste company. “We have C&D landfills all across the country and have waste-to-energy plants that sometimes turn wood waste into energy by burning – but that’s all in the normal course of business,” said Lynn Brown, vice president of corporate communications. She said WM does not track wood waste. “We would have to call each of our more than 300 landfills individually. That’s simply impractical,” Brown said.

The U.S. Environmental Protection Agency reports that the country generated 12.7 million tons of wood waste in 2000. Roxanne Smith, an EPA spokeswoman, confirmed that the regulatory agency has not compiled any new numbers sine then.

The six-year old numbers reveal that wood comprises the largest percent of the residential C&D waste stream – approximately 42 percent. The EPA reports that markets for recovered wood vary across the country. But the market is dominated by mulch and fuel applications. Wood waste from C&D is attractive as fuel because of its low moisture content. Processed or chipped wood is used as composting and as animal bedding.

Salvage or reused wood products are the highest value items, according to the EPA. But this type of recovered wood requires the highest costs for sorting and processing. The EPA said that a major barrier to increased wood recovery is the lack of grade standards for recovered wood. The EPA said there is also a need for technical performance testing to investigate the structural integrity of recovered wood.

“I’m not an expert on wood waste. However an increase in wood waste supply – from disasters and home construction – is a no brainer,” said Chaz Miller, director of recycling, at the National Solid Waste Management Association, in Washington D.C.

“What may not have increased is the recovery rate. Much of the damaged material from hurricanes was commingled,” he said, citing the urgency behind the recovery effort.

Laura Niles, a spokeswoman for EPA Region 4, which covers the Southeast, said the environmental agency did not collect vegetative or building debris following last year’s hurricanes. She said the EPA’s involvement was primarily to collect and dispose of hazardous waste in the form of propane tanks, batteries, paint, flammable materials, corrosives, chlorine, pesticides, waste oil, household chemicals and other chemical waste.

Niles said Hurricane Katrina and Hurricane Rita created a very large amount of debris along the Gulf Coast. She said she saw estimates of about 46 million cubic yards of waste.

Niles said the U.S. Federal Emergency Management Agency and the U.S. Army Corps of Engineers handled the wood waste.

Neither agency provided numbers. The Energy Information Agency, a statistical agency of the U.S. Department of Energy, estimates wood waste that is turned into fuel. The EIA estimates wood waste both from direct use of harvested wood as fuel and from wood waste streams.

Wood waste can be used to generate electric power and thermal output. This type of wood waste comes from a wide variety of sources, including forestland, land clearing, urban trees and landscape residues, according to the EIA. Another resource of wood waste includes manufacturing and wood processing wastes, as well as C&D debris.

The EIA reports that the largest source of energy from wood is pulping liquor, a waste product from the processing of the pulp, paper and paperboard. Many wood and paper manufactures, like Stamford, Connecticut-based International Paper Company, use wood waste to produce their own steam and electricity.

These companies do not reveal their fuel mix, citing competitive reasons, making it hard to track wood-waste-to-energy.

The EIA estimates that in 2005 there was16.87 billion-kilowatt hours of generating capacity from wood and other biomass. Biomass energy is derived from wood, waste and alcohol fuel. The EIA does not separate them out in its estimates.

The statistical agency expects the biomass energy to grow to 57.83 billion-kilowatt hours by 2030 – making it a 7.2 percent average annual growth from 2004 to 2030.

 


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