PBDDs/Fs and PCDDs/Fs in the Raw and Clean Flue Gas during Steady State and Transient Operation of a Municipal Waste Combustor

摘要

Concentration of pofybromiirateddibenzo-p-dioxins, and-dibenzofurans (PBDDs/Fs) and polychlorinated dibenzo-p-dioxins, and -dibenzofurans (PCDDs/Fs), were determined in the pre- and post-air pollution control system (APCS) flue gas of a municipal waste combustor (MWC). Operational transients of the combustor were found to considerably increase levels of PBDDs/Fs and PCDDs/Fs compared to steady state operation, both for the raw and clean flue gas; SPBDDs/Fs increased from 72.7 to 700 pg dscm"1 in the raw, pre-APCS gas and from 1.45 to 9.53 pg dscm"1 in the post-APCS flue gas; ZPCDDs/Fs increased from 240 to 960 ng dscm^1 in the pre-APCS flue gas, and from 1.52 to 16.0 ng dscm'1 in the post-APCS flue gas. The homologue profile of PBDDs/Fs and PCDDs/Fs in the raw flue gas (steady state and transients) was dominated by hexa- and octa-isomers, while the clean flue gas homologue profile was enriched with terra- and penta-isomers. The efficiency of the APCS for PBDD/F and PCDD/F removal was estimated as 98.5% and 98.7%, respectively. The cumulative TEQpcdd/p+pbdd/f from the stack was dominated by PCDD/F: the TEQ^of PBDD/F contributed less than 0.1% to total cumulative toxic equivalency of MWC stack emissions.