title: Quasi-dynamic leaching characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans from raw and solidified waste incineration residues.
abstract: Quasi-dynamic leaching characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from raw and solidified air pollution control (APC) residues were examined via a nine-time multiple leaching test. The effect of injected activated carbon in the APC residues on the PCDD/F leachability was also evaluated. When humic acid solution was used as a leachant, the leaching concentrations of PCDD/Fs fluctuated between the first and the fifth leaching, followed by a gradual increase and then suddenly reached maximum values at the leaching sequences around seventh and eighth. This significant enhancement in PCDD/F leachability was mainly due to an increase in the release of highly chlorinated PCDD/Fs. Leaching of PCDD/Fs with n-hexane was, in contrast, primarily caused by the partitioning of hydrophobic PCDD/Fs between the APC residue surface and the liquid phase of n-hexane. Consequently, the largest leaching concentrations for n-hexane tests achieved at the first leaching, followed by a decrease and reached plateaus. Solidification/stabilization (S/S) decreased the PCDD/F leachability up to the fifth leaching by the use of humic acid solution. However, S/S increased the PCDD/F leaching concentrations and rates with n-hexane. The activated carbon in APC residues significantly inhibited the release of PCDD/F with n-hexane. The inhibiting effect provided by activated carbon was, however, less significant by the use of humic acid solution.
authors.affiliation: Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, No 2, Juoyue Road, Nantsu, Kaohsiung 811, Taiwan, ROC. hchsi@ccms.nkfust.edu.tw <hchsi@ccms.nkfust.edu.tw>
authors.forename: Hsing-Cheng
authors.initials: HC
authors.lastname: Hsi
authors.forename: Lin-Chi
authors.initials: LC
authors.lastname: Wang
authors.forename: Tsung-Hsien
authors.initials: TH
authors.lastname: Yu
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Chang-Chien
mesh_terms: D001572:Benzofurans / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D006586:Hexanes / Q000737:chemistry; D017745:Incineration; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D012037:Refuse Disposal; D012989:Soil Pollutants / Q000737:chemistry*; D012995:Solubility; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D001572:Benzofurans; D006586:Hexanes; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; C026385:n-hexane; D002244:Carbon; C023614:dibenzofuran