title: Field study and theoretical evidence for the profiles and underlying mechanisms of PCDD/F formation in cement kilns co-incinerating municipal solid waste and sewage sludge.
abstract: A field study and theoretical calculations on the profile and formation mechanism of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from two cement kilns co-incinerating municipal solid waste and sewage sludge were performed, and the PCDFs were mainly focused. The back-end areas of the cement kilns were identified to be the major sites of PCDD/F formation according to their distributions in particulate samples from different process stages. The proportions of tetra- to hexa-chlorinated dibenzofurans (∑Cl4-6CDFs) at the kiln back-end areas were in the range of 50-80% of the total PCDD/Fs in mass concentrations and 62-87% in toxic equivalent concentrations. These results indicated that ∑Cl4-6CDFs are the dominant homologs that should be the focus for reducing PCDD/F emissions in cement kilns that co-incinerate municipal solid waste and sewage sludge. It is speculated that the low contents of oxygen and copper compounds, as well as the alkaline conditions, may contribute to the dominance of ∑Cl4-6CDFs in the PCDD/Fs formed. Chlorination was assumed to be the mechanism of formation of PCDFs. The results from model predictions and thermodynamic calculations used to test this assumption were consistent with the PCDF profiles observed from the field study.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing Building Materials Academy of Sciences Research, Beijing 100041, China.
authors.forename: Jiayu
authors.initials: J
authors.lastname: Zhan
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: grliu@rcees.ac.cn.
authors.forename: Guorui
authors.initials: G
authors.lastname: Liu
authors.affiliation: Foreign Economic Cooperation Office, Ministry of Environmental Protection, Beijing 100035, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xiaoxu
authors.initials: X
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
mesh_terms: D003252:Construction Materials; D000072338:Dibenzofurans, Polychlorinated / Q000737:chemistry*; D004867:Equipment Design; D017745:Incineration / Q000295:instrumentation / Q000379:methods*; D008956:Models, Chemical; D000072317:Polychlorinated Dibenzodioxins / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry; D062611:Solid Waste
chemical_list: D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D012722:Sewage; D062611:Solid Waste
keywords: Cement kiln; Co-incineration; Municipal sewage sludge; Municipal solid waste; Polychlorinated dibenzo-p-dioxins; Polychlorinated dibenzofurans