Review of various treatment technologies for chromated copper arsenate CCA -treated wood

3 Review of various treatment technologies for chromated copper arsenate (CCA)-treated wood 

In some circumstances, CCA-treated wood may be mixed with cement and utilized in construction (Gong, Kamdem and Harcihandran, 2004). Wood-cement composites have compressive strengths similar to concrete. However, the composites are far more capable of sustaining plastic deformation than concrete. Therefore, they may be useful in circumstances where compressive strength and energy dissipation are required (Gong, Kamdem and Harcihandran, 2004, 276). 

Kartal and Kose (2003) investigated the removal of arsenic from CCA-treated wood with common chelating agents (EDTA, nitrilotriacetic acid (C6H9NO6), and oxalic acid). Dual mixtures of EDTA and oxalic acid and nitrilotriacetic and oxalic acids removed about 100% of the arsenic from sawdust of the wood. However, only about 80 % of the arsenic was removed from wood chips with the same dual solutions. Once the arsenic, copper, chromium, and any other toxins have been removed from the wood, it could be used as a biofuel. 

Kartal et al. (2004) also investigated the use of fungi to remove arsenic from CCA-treated wood. Three brown-rot fungi (Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus) were initially 

In the study described in Christensen et al. (2004, 230), the arsenic content of the wood before electrodialysis was 837 114 mg kg-1 (95 % confidence level) based on 95 samples. The electrodialytic process was more effective if the wood was first broken down into 2 cm chips and soaked in phosphoric acid followed by oxalic acid (Christensen et al., 2004, 236). The soaking probably leaches a significant amount of the arsenic and metals from the wood, which allows the electrodialytic process to remove most of the remaining arsenic, copper, and chromium (Christensen et al., 2004, 235-236). The most efficient results for all three contaminants, which included 95 % removal of arsenic, used 100 kg of wood chips with a 60-cm spacing between the electrodes. The electrodialysis lasted for 21 days (Christensen et al., 2004, 231). 

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