| dc.description.abstract | Three copper-containing sludge treatment plants (A, B and C plants) in northern Taiwan were investigated for the removal efficiency and emission characteristics of PCDD/Fs and dl-PCBs. The effects of operating parameters and APCDs processes on PCDD/Fs and dl-PCBs of flue gas and fly ash were discussed.The results show that the APCDs of three plants have good HCl and PM removal efficiencies. The PCDD/Fs TEQ concentrations of the stacks in the three plants A, B and C are 0.06, 6.57 and 0.49 ng I-TEQ/Nm3, respectively. The PCDD/Fs concentration of Plant B is not only significantly higher than two other plants, but also exceeds the regulation (0.5 ng I-TEQ/Nm3). The PCDD/Fs concentration of cyclone ash, baghouse ash of the Plant B and the cyclone ash of the rotary kiln, cyclone ash of the copper smelting furnace, the first baghouse ash and the second baghouse ash of Plant C are all higher than the regulation (1.0 ng I-TEQ/g), and are classified as hazardous wastes and must be properly disposed of. The APCDs of Plant B and C have no obvious removal effect for dl-PCBs, and the homologue distributions are mainly TeCB-77 and PeCB-126, and they are mainly distributed in the gas phase. In terms of removal efficiency, the removal efficiency of PCDD/Fs achieved with ACI+ baghouse of Plant B was only 56.7%, which was significantly lower than the other two plants, and the PCDD/Fs mass concentration increased as flue gas passed through the wet scrubber. The distribution of homologue indicates that most of the three plants were dominated by highly-chlorinated species. After passing through the wet scrubber or the baghouse, the gas phase distribution reveals increasing trend. These results indicate that severe “memory effects” occur at these stages. Through the results and comparing the APCDs of the three plants, this study considers that the scrubber is not suitable as the final APCD, and the combustion chamber needs to be stably operated. It is found quenching mechanism can effectively inhibit PCDD/Fs formation, and the negative effect of the memory effect can be alleviated by the subsequent APCDs. | en_US |