以活性碳生物滴濾床去除三氯乙烯、甲苯與丙酮混合有機廢氣之研究

Abstract

我國近年來由於高科技半導體產業的快速成長，使半導體產業已成為我國主力產業之一，隨之而來的污染問題也就日漸受到重視。在半導體產中，所產生的氣狀污染物，除酸氣外主要為揮發性有機物VOCs (Volatile Organic Compounds)，其主要成分包括丙酮、甲苯與三氯乙烯等有機物。本研究對人工模擬半導體產業產生有機廢氣（丙酮、甲苯與三氯乙烯），以活性碳為濾料之生物滴濾塔反應器，配合強化馴養後之混合菌種之植種方式，進行去除效能與穩定性之評估。本研究經強化馴養後植入反應器之微生物中，對三氯乙烯具共代謝之菌株有三株Pseudomonas菌與一株Sphingomonas菌，且Pseudomonas菌之共代謝作用較Sphingomonas菌強。整體來看，Pseudomonas與Sphingomonas兩菌屬在馴養後的微生物相中，是可行共代謝之主要菌屬，而Mycobacterium lacticola與Acetobacteriaceae兩株菌則為整個菌相中丙酮主要的分解菌。 系統在173天的連續操作期間，當進流總碳氫化合物濃度在2400 ppmv範圍內，空塔停留時間為155 秒之操作條件下，THC之去除率與進流各物種之去除率皆可達到90%以上。本研究之系統在丙酮進流負荷小於120 g/m3/day、甲苯進流負荷小於77 g/m3/day以及三氯乙烯之進流負荷小於23 g/m3/day 時，反應器對此三種有機污染物的去除效率皆可達到90%以上。若操作期間加入少量葡萄糖作為誘導劑可將THC去除效率提升至93%，而三氯乙烯之去除率則可提升至95%以上。由本研究之結果顯示，對於人工模擬之三氯乙烯、丙酮與甲苯的混合有機廢氣，此活性碳濾料之生物滴濾塔反應器可穩定而有效地處理之。因此，對於解決半導體產業因有機廢氣而產生之污染而言，此系統極具有經濟之可行性與發展之潛力。

The blooming of semiconductor industry has brought serious concerns over its negative environmental impacts. The exhausts from the semiconductor industry contains acidic waste gas and Volatile Organic Compounds(VOCs), including acetone, toluene and trichloroethylene. This study investigated the feasibility of biofiltration technology in removing volatile organic compounds (VOCs) emitted from a semiconductor manufacturing factory. A bench-scale bio-trickling-bed packed with GAC inoculated with mixed consortium of microorganisms was used to evaluate the effectiveness in treating synthetic gas mixture acetone, toluene, and trichloroethylene. Among these microorganisms, three strains of Pseudomonas and strain of Sphingomonas were able to degrade TCE and toluene by co-metabolism. The Pseudomonads were more effective than the Sphingomonas. Over all speaking, the Pseudomonads and Sphingomonas were the major groups of co-metabolizing TCE and toluene, while, Mycobacterium and the Acetobacteriaceae were the main decomposers of acetone. During the continuous operation of 173 days, the overall removal of total hydrocarbon (THC) reached above 90% when the inlet concentration of THC was kept 2400 ppmv. When the loading capacities of acetone, toluene, and TCE were kept at 120, 77, and 27 g/m3/day, respectively, more than 90% removal efficiencies were achieved all three waste gases. The low environmental impact and the high operation stability in addition to the reasonably high removal efficiency suggest the bio-reactor a promosing technology for treat waste gas from semiconductor industry.