Evaluation of the leachability of polychlorinated dibenzo-p-dioxins and dibenzofurans in raw and solidified air pollution control residues from municipal waste incinerators.
Leachability of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from raw and solidified air pollution control (APC) residues with selected solvents, including acetic acid, simulated acid rain, humic acid, linear alkylbenzene sulfonate (LAS) and n-hexane was investigated. High-chlorinated PCDD/F congeners were observed in all leachates of raw APC residue samples, with the largest total leaching concentration (61.60 ngm(-3); 0.30 ngI-TEQm(-3)) from treatment with humic acid. Low-chlorinated congeners were mainly leached with LAS and n-hexane. Solidification and stabilization (S/S) processes with cement and sulfur-containing chelating agent decreased the leachability of PCDD/Fs by up to 98% with humic acid and LAS as solvents. However, S/S processes enhanced the leachability of both high- and low-chlorinated PCDD/F congeners with n-hexane as the solvent, which largely increased the toxic equivalent quantity of leachates. These results suggest that conventional S/S processes may effectively restrain the release of PCDD/Fs when APC residues are leached with rain water or natural organic compounds (e.g., humic acid), but may have a deteriorated effect when APC residues are leached with nonpolar organic solvents (e.g., n-hexane) coexisting in the landfill sites.
Hsi
Hsing-Cheng
HC
Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, No. 2, Juoyue Rd., Nantsu, Kaohsiung 811, Taiwan, ROC. hchsi@ccms.nkfust.edu.tw
Yu
Tsung-Hsien
TH
D000395:Air Pollutants, Occupational / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control*; D001572:Benzofurans / Q000032:analysis*; D002614:Chelating Agents / Q000737:chemistry; D004784:Environmental Monitoring; D006812:Humic Substances / Q000032:analysis; D017745:Incineration; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D011108:Polymers / Q000032:analysis*; D012037:Refuse Disposal; D012995:Solubility; D012997:Solvents; D013501:Surface-Active Agents; D013624:Taiwan; D014961:X-Ray Diffraction
D000395:Air Pollutants, Occupational; D001572:Benzofurans; D002614:Chelating Agents; D006812:Humic Substances; D000072317:Polychlorinated Dibenzodioxins; D011108:Polymers; D012997:Solvents; D013501:Surface-Active Agents; C016068:polychlorodibenzofuran