CCA Wood Incineration

Researchers at the University of Florida have demonstrated that existing stack-scrubbing technology can be applied to wood-burning boilers to remove and render insoluble volatilized heavy metals from the

incineration of CCA-treated wood (see

EBN

Vol. 6, No. 3 for background discussion). Bubbling stack exhaust through lime-water (an aqueous solution of calcium carbonate) is used to remove sulfur dioxide (SO₂) in power plants that burn high sulfur fuel, such as coal—the by-product is calcium sulfate or gypsum. The researchers applied the same general approach to wood incinerators burning CCA-treated wood, and vaporized heavy metals were reacted out into relatively insoluble salts. So, not only are the hazardous metals removed from stack emissions, the incinerator ash is less likely to leach during solid waste disposal. This research may be desperately needed in Florida, where, according to the Florida researchers, an estimated 70% of waste treated wood is incinerated, and the total amount of treated wood discarded in Florida will rise from 5 million ft³ (140,000 m³) today to 35 million ft³ (990,000 m³) in 2015!