Distribution of Polybrominated Dibenzo-p-dioxins and Dibenzofurans and Polybrominated Diphenyl Ethers in a Coal-fired Power Plant and Two Municipal Solid Waste Incinerators

In this study, the distributions of polybrominated dibenzo-p-dioxins (PBDD/Fs) and dibenzofurans and polybrominated diphenyl ethers (PBDEs) in the bottom residues of the combustion chambers (BR), the fly ashes from superheaters (SH), economizers (EC), semi-dry scrubbers (SDA), fabric filters (BF), fly-ash pits (FAP) and stack flue gases (SFG) of two municipal solid waste incinerators (MSWIs) and the bottom residue (BR), electrostatic dust precipitators (ESD), and stack flue gases (SFG) of a coal-fired power plant (TPP) were investigated. BR of combustion chambers exhibited the highest content of PBDEs and PBDD/Fs among all the units. The amount of PBDE mass found in bottom residues constituted 99.7% at MWSI-A, and 92.6% at MSWI-B and 75.1% at TPP of the total PBDE discharges, respectively; while the second highest PBDE mass observed in MSWI-A and MSWI-B was from SFG (0.146%) and EC (5.54%), respectively. In TPP, the PBDE distribution was 75.1% in BR, 12.5% in ESD, and 12.4% in SFG. The mean concentrations of PBDEs emitted from SFG of MSWI-A, and MSWI-B were 9.32 ng/Nm(3), and 7.62 ng/Nm(3), respectively; however, that of PBDE discharged from SFG of TPP was only 5.43 ng/Nm(3). The dominant congener found from MSWI-A, MSWI-B and TPP, was BDE-209, accounting for 65.9%, 77.7%, and 77.6% of total PBDE concentrations in SFG, respectively; whereas BDE-206 (6.01%-6.36%) was the second highest congener. Meanwhile, the PBDE emission factors from the stack flue gases were 35.6 +/- 10.9 mu g/ton-waste at MWSI-A, 47.6 +/- 29.4 mu g/ton-waste at MSWI-B and 62.9 +/- 10.9 mu g/ton-coal at TPP of the total PBDEs, respectively; showing the PBDE emission rates and contributions of TPP to the ambient air are actually much higher than those of MSWIs, while the PBDE concentrations in SFG of TPP were lower than MSWIs'. Further investigations on the safety of BR reutilization and the impact of SFG from TPP are strongly advised.