多氯聯苯(PCBs)為環境賀爾蒙之一，近年來陸續有許多研究證實在焚化系統中會產生PCBs，本研究針對大型垃圾焚化廠(MSWI)、電弧爐煉鋼廠(EAF)及小型廢棄物焚化廠(IWI)進行煙道氣及灰渣採樣，以建立焚化系統中灰份及煙道氣中PCBs含量資料，並探討不同系統對多氯聯苯含量及物種分佈相異之處。並掌握各廠中多氯聯苯之流佈特性。 MSWI兩次採樣結果顯示該廠APCD對多氯聯苯並無明顯的去除效果；兩次採樣其PCBs物種分佈相當一致，主要優勢物種為PCB-77、118和126；就毒性當量濃度百分比而言，PCB-126為最主要之物種(90%以上)，PCB-169次之，此兩種物種即佔總濃度之95%以上。EAF相同批次中，不管氧化及還原期，各採樣點PCBs濃度皆以煙道排氣中PCBs濃度低；在PCBs物種分佈方面，三個採樣點氣流中PCBs物種以PCB-77、105、118及126為主要物種；氣固相比率方面，不管氧化及還原期，氣流愈往下游固相比率有下降趨勢，顯示EAF廠中cyclone及baghouse能有效去除粒狀物，導致固相比率減少。IWI濕式EP前後固相PCBs濃度分別為16.46 ng/Nm3及3.48 ng/Nm3，固相濃度大量減少；而煙囪處氣相PCBs濃度(5.5 ng/Nm3)低於活性碳吸附塔前氣相濃度(17.9 ng/Nm3)，顯示活性碳對於PCBs有吸附能力，導致氣相濃度的減少。因IWI及MSWI為焚化系統而EAF則為高溫製程系統，由三廠中煙道排氣PCBs物種分佈結果IWI與MSWI煙道排氣中PCBs分佈相似，顯示相似的焚化系統會產生相似的物種分佈；而三廠排放濃度以EAF廠最高，MSWI最低；就毒性當量濃度而言，因IWI產生毒性最高的PCB-126濃度高於其他兩廠，導致IWI毒性當量濃度為三廠中最高。 Previous studies indicate the industrial activities containing combustion process contribute significantly to PCB emissions. This study investigates PCB concentrations and their characteristics in stack gases and ashes in MSWI, EAF and IWI, respectively. In the MSWI investigated, the results reveal the APCD did not remove PCBs effectively. Major PCB congeners measured in flue gases include PCB-77, 118, and 126. PCB-126 accounts for more than 90％ of the TEQ contributed by coplanar PCBs. If combined with PCB-169, these two non-ortho-substituted PCB accounts for more than 95% of PCB-TEQ. The PCBs concentration in stack of the EAF are the lowest among three emission sources investigated. As for the distribution between gas and particle phases, the ratios of gas/particulate phase PCBs increases as the flue gases flow downstream. Characteristics of PCB congeners distribution and removal efficiency of wet-EP and fixed carbon bed of an IWI are investigated in the study. The concentration of particle-phases PCBs at wet-EP outlet was reduced compared to that measured at wet-EP inlet. The results indicate that the particle-phase PCB concentrations are significantly reduced. Hence, wet-EP could effectively remove particulate-phase PCBs. Gas-phase PCBs the concentration at stack was lower than that at fixed carbon bed inlet. Results show that activated carbon bed could adsorb PCBs, hence reduce gas-phase PCBs. Characteristics of PCB congeners distribution of IWI and MSWI were similar. This indicates that similar processes had the similar PCBs congeners distribution. The PCBs concentration in stack of EAF was the highest among three sources investigated, while of the IWI had the highest PCBs TEQ concentration. It is attributed to the higher PCB-126 concentration measured at the IWI than other two plants.
