| 摘要: | 中文摘要
焚化過程產生之粉塵可能含有各種有害成分，焚化廠作業勞工可能暴露於有害粉塵而危害身體健康，過去相關粉塵研究多以都市垃圾焚化廠為主，因此本研究以有害事業廢棄物焚化廠為對象，探討廠內之投料處(S1)、旋轉窯與二次燃燒室底灰卸料處(S2) 、冷卻塔底部(S3)、緩衝塔底部(S4)與空氣汙染防治設備飛灰卸料處(S5)等各單元作業逸散之氣膠特性；且將採樣結果與觀察記錄比對以瞭解影響焚化廠粉塵逸散之活動，並根據逸散粉塵之特性，提出粉塵防護之改善建議。
研究使用粉塵粒徑分析儀(Grimm 1.109)於焚化廠正常運轉時在五個單元作業進行連續八小時定點之粉塵採樣，而停爐及歲修時僅於S2處進行採樣，量測項目包括與職業衛生有關之可吸入性、胸腔性及可呼吸性粉塵與環境品質有關的PM10、PM2.5及PM1.0、粉塵質量及粒數粒徑分布(0.25 μm～32 μm)。此外，使用粉塵粒徑分析儀搭配掃描式電移動度微粒粒徑分析儀(SMPS)於S2與S5處正常操作時，進行兩小時粒數粒徑分布(18.1 nm～32 μm)之量測。
有害事業廢棄物焚化廠正常運轉、停爐及歲修時，各單元作業之可呼吸性粉塵濃度平均分布百分比為14.27 %~29.68 %，作業活動均會導致可吸入性、胸腔性及可呼吸性三種粉塵質量濃度顯著增加，尤其產生的大微粒更是明顯提高可吸入性粉塵比例。三種與職業衛生有關的粉塵濃度以在S2歲修時測得最高，正常運轉時則以S5之粉塵濃度最高。在正常運轉、停爐及歲修時，焚化廠環境中之PM10以S5之平均濃度最高且變化最大；而PM2.5及PM1.0則S3濃度最高。有害事業廢棄物焚化作業排放至廠內環境空氣中的微粒以細微粒(PM2.5)分布為主；S5飛灰卸料作業粉塵逸散嚴重且平均質量濃度最高。
質量粒徑分布顯示，除S3因管件洩漏產生大量0.7 m以下的燻煙微粒外，其他各處作業活動造成粉塵質量濃度增加之氣膠粒徑主要分布在大粒徑1.5 m以上。粒數粒徑分布顯示，S1平均粒數濃度最高，各單元作業活動造成粒數濃度增加之主要粉塵粒徑皆分布在次微米範圍。作業活動導致S2粉塵粒徑分布由次微米與奈米範圍轉移至奈米範圍，S5飛灰卸料作業會明顯增加奈米微粒的產生。
本研究以光學儀器進行粉塵採樣分析，評估出S2歲修作業以及S5正常操作之飛灰卸料作業之勞工具有較高的粉塵暴露潛勢。根據量測之氣膠特性及現場運作實況，建議有害事業廢棄物焚化廠可採取粉塵逸散源之工程控制、環境傳播途徑控制及個人防護進行粉塵危害預防。本研究結果可作為類似有害事業廢棄物焚化廠內粉塵作業之職業衛生管理的參考。
關鍵字：廢棄物、焚化廠、粉塵、可呼吸性、粒徑分布
Hazardous dust exposure may cause adverse health effects on incinerator workers because generated dust during incineration may contain different toxic compounds. Studies related to emitted dust in incinerators almost focused on municipal incineration plants over the past years. Therefore, the aim of this study was to explore the characteristics of mitted dust at the areas of waste feeding (S1), rotary kiln and discharge of bottom ash from afterburner (S2), cooling tower (S3), buffering tower (S4), and fly ash discharge from air pollution control equipment (S5) in a hazardous industrial waste incineration plant. This study presented the suggestions of dust hazard prevention strategies according to the measured results of dust combined the observation records in sampling areas.
A dust size analyzer (Grimm 1.109) measured dust continuous for 8 hours at five areas (S1~S5) during the period of normal operation and only at S2 during periods of furnace shutdown and annual maintenance. The measured dust items included inhalable dust, thoracic dust, respirable dust, PM10, PM2.5, PM1.0, and mass and number size distributions (0.25 μm～32 μm). In addition, the dust size analyzer and a scanning mobility particle sizer (SMPS) measured dust number size distributions (18.1 nm～32 μm) simultaneously for two hours at S2 and S5 during the period of normal operation.
The percentages of respirable dust were 14.27 %~29.68 % in the hazardous industrial waste incineration plant during periods of normal operation, furnace shutdown and annual maintenance. All the working activities at each area increased inhalable, thoracic, and respirable dust mass concentrations. Especially, the generated big particles obviously increased the percentage of inhalable dust. The highest measured mass concentrations of inhalable, thoracic, and respirable dust were at S2 during the period of annual maintenance and S5 during the period of normal operation. The highest measured dust mass concentrations of PM10 and PM2.5 during periods of normal operation, furnace shutdown and annual maintenance were at S5 and S3, respectively. The major emitted dust were fine particles (PM2.5) in this incineration plant. The emitted dust pollution by fly ash discharge from air pollution control equipment (S5) was the most serious. Fly ash discharge generated the highest average mass concentrations.
Mass size distributions indicated the major sizes of aerosols, which caused the increase of dust mass concentrations by working activities, were greater than 1.5 m at four areas expect for S3 generating many fume soots with diameters less than 0.7 m because of pipe fitting leakage. Number size distributions showed the highest average dust number concentrations appeared at S1. The major sizes of dust, which caused the increase of dust number concentrations by working activities, distributed in the range of submicrometer. The particle size distributions at S2 shifted from the range of submicrometer into nanometer because of effects of working activities. The working of discharging fly ash at S5 can significantly increase the emission of nanoparticles.
The workers who charged the annual maintenance work at S2 and fly ash discharge at S5 during the period of normal operation were the higher potential dust exposure group than other areas. This study suggested the strategies of dust hazard prevention for workers including engineering control of emitted source, path control of environmental transportation, and personal protective equipment. These results can provide as the reference of occupational health management on dust working for similar hazardous industrial waste incineration plants.
Keywords: Waste, Incinerator, Dust, Respirable, Size distribution |
