都市廢棄物焚化爐持久性有機污染物之排放特徵

Characteristics of persistent organic pollutants from a municipal solid waste incinerator

王茂松(Mao-Sung Wang)

指導教授 ： 陳瑞仁 ； 黃國林

國立屏東科技大學/工學院/環境工程與科學系所/博士(2010年)

https://doi.org/10.6346/NPUST.2010.00209

摘要

自從戴奧辛與呋喃(PCDD/Fs)首次在都市垃圾焚化爐之煙道廢氣與飛灰被發現後，已在許多國家成為一嚴肅之課題。多氯聯苯(PCBs)被廣泛的使用及應用，使得都市垃圾焚化爐也被認為是環境中PCBs的主要貢獻來源。由於溴化戴奧辛與呋喃(PBDD/Fs)可能會經由生產製造溴化耐燃劑過程和燃燒含溴化耐燃劑之廢棄物時生成，而使得PBDD/Fs散佈至環境中越來越受到重視。本研究目的為發展一有效且穩定的多層管柱萃取與分析方法，並探討五種目標污染物於焚化爐之排放特徵。
本研究以多層管柱(矽膠、氧化鋁及活性碳)進行樣品前處理並使用高解析度氣相層析儀與高解析度質譜儀進行大型垃圾焚化爐大氣、煙道及灰渣中氯化戴奧辛(PCDD/Fs)、多氯聯苯(PCBs)、溴化戴奧辛(PBDD/Fs)及多溴聯苯醚(PBDEs))分析。本方法已藉由空白樣品與添加樣品分析得到驗證。空氣樣本中PCDD/Fs、PCBs、PBDD/Fs、PBDEs及PBBs濃度分別為59.6 fg WHO-TEQ/Nm3、6.74 fg WHO-TEQ/Nm3、12.2 fg WHO-TEQ/Nm3、52100 fg/Nm3 及341 fg/Nm3。PCB 及PBDD/Fs之WHO毒性當量值分別佔總WHO毒性當量濃度(PCDD/Fs、PBDD/Fs與PCBs總和) 之8.9% 及16%。由於溴化戴奧辛與多氯聯苯化合物同樣具有持久性及毒性，因此大氣中溴化戴奧辛與多氯聯苯化合物應一併加以管制。
煙道樣本中PCDD/Fs、PCBs、PBDD/Fs、PBDEs及PBBs濃度分別為0.0719 ng WHO-TEQ/Nm3、0.00169 ng WHO-TEQ/Nm3 、0.00546 ng WHO-TEQ/Nm3、20.7 ng/Nm3及0.958 ng/Nm3。煙道樣本中PCDD/Fs、PCBs、PBDD/Fs、PBDEs及PBBs排放係數分別為0.300 µg WHO-TEQ/ton-waste、0.00667 µg WHO-TEQ/ton-waste、0.0207 µg WHO-TEQ/ton-waste、84.5 µg/ton-waste及 1.05 µg/ton-waste。結果顯示，焚化爐煙道除了戴奧辛排放之外，溴化難燃劑之排放亦不容忽視且仍需要後續研究的進行。
本研究探討焚化爐過熱器(SH)、節熱器(HE)、半乾式洗滌塔(SDA)、袋式集塵器(BF)、飛灰儲存筒(FAP)及廠內燃燒室(BA)等各單元灰渣中五種污染物濃度。各單元灰渣中總PCDD/Fs以節熱器含量最高，因其操作溫度落在合適PCDD/Fs生成之溫度區間內(250℃-400℃)而經由de novo生成。PCBs 及PBBs濃度皆以袋式集塵器飛灰為最高; PBDD/Fs與PBDEs含量則以燃燒室底灰為最高。研究結果顯示：各單元灰渣中總PCDD/Fs及PCBs含量與各單元之操作溫度有明顯相關性；總PBDD/Fs及PBDEs含量與廢棄物焚化爐進料含有溴化難燃劑有關。焚化爐五種污染物主要經由飛灰排放，由於節熱器與袋式集塵器灰渣濃度已超過國內管制限值(1 ng I-TEQ/g)，故未來應針對節熱器與袋式集塵器進行後續處理。

關鍵字

都市廢棄物焚化爐 ； 溴化難燃劑 ； 管柱層析 ； 持久性有機污染物 ； 排放係數 ； 分佈

並列摘要

Since polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were first discovered in flue gases and the fly ash of MSWIs, PCDD/F emissions have become one of the most controversial issues associated with MSWI. MSWIs have also been identified as the largest contributors to the environmental levels of polychlorinated biphenyls (PCBs) due to the wide use and application of the PCBs mixtures. Concerns about polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) have increased, because PBDD/F can be generated in some production and waste incineration processes involving plastics containing brominated flame retardants. The goal of this study was to develop an efficient and stable analytical method for determining the quantity of five target compounds (including 2,3,7,8-substituted PCDD/Fs and PBDD/Fs, PBDEs, PCBs, and PBBs) from a single sample extraction by combining multiple columns and to characterize emissions of five target compounds in the whole MSWI.
A comprehensive technique, based on multiple (silica, alumina, and active carbon) columns, can be applied to prepare samples for determining the five group compounds in stack gases, air samples and ashes based on high-resolution gas chromatography/high-resolution mass spectrometry. The method was also validated by analyses of blank and spiked samples. In the sampled air, the mean PCDD/F, PCB, PBDD/F, PBDE, and PBB concentrations were 59.6 fg WHO-TEQ/Nm3, 6.74 fg WHO-TEQ/Nm3, 12.2 fg WHO-TEQ/Nm3, 52100 fg/Nm3, and 341 fg/Nm3, respectively. The WHO-TEQ of PCB and PBDD/Fs counted for 8.9% and 16% of total TEQ (summed over PCDD/Fs, PBDD/Fs, and PCBs), respectively, suggesting that the atmospheric concentrations of dioxin and dioxin-like compounds should be regulated together because of the persistence and toxicity of PBDD/Fs and dioxin-like PCBs.
The sample cleanup procedures that are combined with a multiple column were applied to determine the quantities of five persistent organic pollutants (PCDD/Fs, PBDD/Fs, PBDEs, PCBs, and PBBs) simultaneously from single stack gas samples collected from a large-scale MSWI in Taiwan. The mean concentrations of PCDD/Fs, PBDD/Fs, PCBs, PBDEs, and PBBs in the flue gases of the MSWI were 0.0719 ng WHO-TEQ/Nm3, 0.00169 ng WHO-TEQ/Nm3, 0.00546 ng WHO-TEQ/Nm3, 20.7 ng/Nm3, and 0.958 ng/Nm3, respectively. The emission factors of PCDD/Fs, PBDD/Fs, PCBs, PBDEs, and PBBs were 0.300 µg WHO-TEQ/ton-waste, 0.00667 µg WHO-TEQ/ton-waste, 0.0207 µg WHO-TEQ/ton-waste, 84.5 µg/ton-waste, and 1.05 µg/ton-waste, respectively. Therefore, the emissions of not only PCDD/Fs but also BFRs from MSWIs should not be ignored and need further investigation.
Data on levels and emission factors of the five target compounds in the different units (super heater (SH), heat economizer (HE), semi-dryer absorber (SDA), bag-house filter (BF), and fly ash pit (FAP), and bottom ash (BA) discharger)of the MSWI were first reported. The PCDD/Fs were found in high content in the HE, mainly because of the operating temperature range (250–400 °C) which is favorable for PCDD/F formation through de novo synthesis. High concentrations PCBs and PBBs were detected in the BF. The highest concentrations of PBDD/Fs and PBDEs were observed in the BA. A significant correlation existed between content of PCDD/F and PCB in individual ash and corresponding operating temperature, while the content of ash-bound PBDD/Fs and PBDEs chiefly related to feeding wastes that contained brominated flame retardants. The emission of the five pollutants in the MSWI was primarily from fly ash. Further treatment is necessary for ash collected from the HE and BF because the ash had total-PCDD/F content exceeding the regulation limit (1 ng I-TEQ/g) in Taiwan.

並列關鍵字

Municipal solid waste incinerators ； Brominated flame retardants ； Column chromatography ； Persistent organic pollutants ； Emission factors ； Distribution

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