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標題: | 紫外光結合自由餘氯對於Acinetobacter baylyi之自然轉形抑制效果 Reduction of Acinetobacter baylyi Transformation Competence by UV/Chlorine Process |
作者: | 陳韋妡 Wei-Hsin Chen |
指導教授: | 童心欣 Hsin-Hsin Tung |
關鍵字: | 紫外光結合餘氯高級氧化程序,紫外光波長,消毒,水平基因轉移,自然轉形, UV/chlorine advanced oxidation process (UV/chlorine AOP),Ultraviolet wavelengths,Disinfection,Horizontal gene transfer,Natural transformation, |
出版年 : | 2022 |
學位: | 碩士 |
摘要: | 二十一世紀初起,抗生素抗性開始成為全球所重視的公共衛生議題。傳統加氯消毒被發現具有篩選特定抗生素抗性基因的能力,並能共選擇出同時具有抗氯及抗生素抗性能力的細菌,低餘氯劑量及消毒副產物均被證實具有促進水平基因轉移發生的能力,因此加氯消毒已逐漸不足以確保水質供應之安全性。紫外光催化高級氧化處理具有處理難分解有機物及微污染物的實績,隨著紫外光發光二極體(UV-C LED)的發展漸趨成熟,製造特定波長的紫外光光源的可行性大幅提升,因此可作為替代性紫外光光源,應用於UV/chlorine高級氧化程序中。本研究以自然轉形勝任細菌A. baylyi及pWH1266質體作為模式系統,評估紫外光結合自由餘氯高級氧化處理程序之抗生素抗性基因水平基因轉移風險,並探討相較於254 nm波長之低壓汞燈,275 nm波長之紫外光發光二極體應用於UV/chlorine高級氧化程序是否能有效提升對A. baylyi的消毒能力及自然轉形的抑制能力。結果發現紫外光結合7.5 mg-Cl2/L之初始自由餘氯對於A. baylyi之消毒有協同作用(synergistic effect)效果,且以單位紫外光劑量對於A. baylyi之對數消毒能力 (mJ/cm2 per log inactivation)進行比較,發現UV-C LED (275 nm)結合自由餘氯對於A. baylyi之消毒效果皆優於LPUV (254 nm),顯示275 nm波長之紫外光光源更適合應用於本研究之UV/chlorine高級氧化程序中。此外,隨著自由餘氯加氯劑量的提升,初始自由餘氯Ct值為3.0 mg-Cl2·min /L時,UV-C LED (275 nm)結合自由餘氯即可有效抑制60%之轉形菌生長;初始自由餘氯Ct值為7.5 mg-Cl2·min /L時,LPUV (254 nm)結合自由餘氯才可有效抑制50%之轉形菌生長,因此以UV-C LED (275 nm)作為UV/chlorine的紫外光光源相較LPUV (254 nm)更適合抑制自然轉形的發生。 Antibiotic resistance has been a public health issue since the early 21st century, giving rise to the examination of antibiotic resistance genes, and antibiotic resistance bacteria removal efficacy by existing water treatment processes. Chlorine is the most widely used disinfectant in water and wastewater treatment plants. However, chlorination is found to be insufficient to provide water resource security, since chlorine was found to be able to co-select both chlorine-resistance and antibiotic-resistance bacteria, as well as promote the horizontal gene transfer mechanisms in some bacteria. UV/chlorine advanced oxidation process is one of the promising water treatment technologies; owing to their fast reaction rate and strong oxidation capability, they can deal with micropollutants and recalcitrant organics. This study investigates the potential application of 275 nm ultraviolet light-emitting diodes (UV-LEDs) in UV/chlorine AOP by estimating the removal of natural transformation competent bacteria A. baylyi and the reduction of the follow-up transformation efficiency. The results suggest that UV-C LED (275 nm) is more suitable to disinfect A. baylyi than LPUV (254 nm) in the studying system by comparing log removal of A. baylyi, and the synergistic effect from UV and chlorine is observed with initial free chlorine dosage 7.5 mg-Cl2/L. In addition, with increasing spikes of the initial chlorine dosage, UV-C LED (275 nm)/chlorine can reduce 60% of the transformants with 3.0 mg-Cl2·min/L initial chlorine Ct value; LPUV (254 nm)/chlorine can reduce 50% of the transformants after promoting the initial chlorine Ct value up to 7.5 mg-Cl2·min/L, indicating UV-C LED (275 nm) is also more suitable to reduce transformation efficiency of A.baylyi than LPUV (254 nm) with lower initial chlorine dosage in this study. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/89655 |
DOI: | 10.6342/NTU202204219 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 環境工程學研究所 |
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