Article

Review of disposal technologies for chromated copper arsenate (CCA) treated wood waste, with detailed analyses of thermochemical conversion processes

Department of Mechanical Engineering, University of Leuven, Louvain, Flemish, Belgium
Environmental Pollution (Impact Factor: 4.14). 04/2005; 134(2):301-14. DOI: 10.1016/j.envpol.2004.07.025
Source: PubMed

ABSTRACT

Several alternative methods for the disposal of chromated copper arsenate (CCA) treated wood waste have been studied in the literature, and these methods are reviewed and compared in this paper. Alternative disposal methods include: recycling and recovery, chemical extraction, bioremediation, electrodialytic remediation and thermal destruction. Thermochemical conversion processes are evaluated in detail based on experiments with model compounds as well as experimental and modelling work with CCA treated wood. The latter category includes: determination of the percentage of arsenic volatilised during thermal conversion of CCA treated wood, identification of the mechanisms responsible for arsenic release, modelling of high temperature equilibrium chemistry involved when CCA treated wood is burned, overview of options available for arsenic capture, characterisation of ash resulting from (co-)combustion of CCA treated wood, concerns about polychlorinated dibenzo-p-dioxins/furans (PCDD/F) formation. Finally, the most appropriate thermochemical disposal technology is identified on short term (co-incineration) and on long term (low-temperature pyrolysis or high-temperature gasification).

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    • "Energy recovery is the primary disposal pathway for recycled wood waste as it leads to significant volume reduction as well as provides a way to convert waste to energy [8] [10]. It is estimated that more than 50% of CCA-treated wood waste is burned in waste-to-energy plants in the state of Florida [11] [12]. "
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    ABSTRACT: Past studies have shown that many alumino-silicate mineral sorbents are effective in controlling heavy metal emission during incineration. The objective of this study was to identify Al-Si based mineral sorbents that can minimize leaching of heavy metals from the incinerator ash of Chromated Copper Arsenate (CCA-) treated wood. Experiments were carried out using CCA metal spikes combined with Al-Si sorbents, heated to 700 oC, 900 oC and 1100 oC for 30 minutes. The residual ash was leached using the toxicity characteristic leaching procedure (TCLP). X-Ray Diffraction (XRD) analysis was conducted to determine the crystalline speciation of the products. Results showed that low leaching was observed for chromium, below the 5 mg/L TC limit, by alumina and silica at all temperatures, and kaolin at higher temperatures (900 oC and 1100 oC). For copper, all sorbents displayed low leaching values (< 51 mg/l) as compared to the baseline. For arsenic, all sorbents exceeded the TC limit. Speciation characterization results revealed the formation of several metal-metal and metal-mineral compounds that might have resulted in different leaching behaviors of each metal-sorbent pair under different combustion conditions. The results suggest that a combination of sorbents at different stages of the combustion process can be effective to control the leaching of CCA metals.
    Full-text · Article · Dec 2015 · American Scientific Research Journal for Engineering, Technology, and Sciences
    • "Incineration, as a process of changing wood waste into energy, is a relatively easy way to recycle the treated wood waste, which may resolve the problem of the shortage of landfill space. However open burning of inorganic arsenical and pentachlorophenol treated wood can have deleterious health and environmental effects and is not recommended (Helsen and Van den Bulck 2005; Tame et al. 2007) and fly ashes and volatile components is not appropriate. Bioremediation of CCA-treated wood was also studied in detail by several researchers (Stephan et al. 1996; Clausen and Smith 1998; De Groot and Woodward 1998; Clausen 2000; Kartal and Clausen 2001; Clausen 2004; Kartal et al. 2004a, b, 2006; McMahon et al. 2009; Kim et al. 2009; Sierra-Alvarez 2009; Choi et al. 2013). "
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    ABSTRACT: Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate (CCA). However, one problem has not been addressed: the effects of wood species and retention levels on remediation efficiency. The objectives of this study were to investigate the effects of wood species and retention levels on removal of copper, chromium, and arsenic from CCA-treated wood samples using sodium hypochlorite. Our results showed that sodium hypochlorite (NaOCl) was very effective for removal of copper, chromium, and arsenic from CCA-C treated milled wood samples for all three species used in this study. The Cu, Cr, and As extraction efficiencies for red pine were 95 % Cu, 97 % Cr and 94 % As, for maple were 95 % Cu, 97 % Cr, and 98 % As at 4.0 kg m - 3 retention levels, and for aspen were 95 % Cu, 92 % Cr, and 91 % As at 9.6 kg m - 3 retention level, respectively. However, the results showed that wood species and initial retention levels of CCA-treated wood products played very impor- tant roles in terms of removal of Cu, Cr, and As.
    No preview · Article · Nov 2015 · Journal of Forestry Research
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    • "mg Cr g −1 , 2.6–9.8 mg Cu g −1 [14] [15] [16] "
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    ABSTRACT: Pyrolysis or combustion of waste wood can provide a renewable source of energy and produce byproducts which can be recycled back to land. To be sustainable requires that these byproducts pose minimal threat to the environment or human health. Frequently, reclaimed waste wood is contaminated by preservative-treated timber containing high levels of heavy metals. We investigated the effect of feedstock contamination from copper-preservative treated wood on the behaviour of pyrolysis-derived biochar and combustion-derived ash in plant-soil systems. Biochar and wood ash were applied to soil at typical agronomic rates. The presence of preservative treated timber in the feedstock increased available soil Cu; however, critical Cu guidance limits were only exceeded at high rates of feedstock contamination. Negative effects on plant growth and soil quality were only seen at high levels of biochar contamination (>50% derived from preservative-treated wood). Negative effects of wood ash contamination were apparent at lower levels of contamination (>10% derived from preservative treated wood). Complete removal of preservative treated timber from wood recycling facilities is notoriously difficult and low levels of contamination are commonplace. We conclude that low levels of contamination from Cu-treated wood should pose minimal environmental risk to biochar and ash destined for land application.
    Full-text · Article · Jun 2014 · Journal of Hazardous Materials
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