污泥厌氧消化过程中抗生素抗性基因的行为特征

发布时间：2018-07-04 21:18

  本文选题：抗生素 + 抗性基因　； 参考：《浙江大学》2015年硕士论文

【摘要】：污水处理厂剩余污泥中含有高浓度的抗性基因,但对污泥进行有效处理处置以降低其环境风险的研究还很少,目前已有研究表明厌氧消化技术能有效削减污泥中的抗性基因。因此,本研究以城市污水处理厂剩余污泥为主要研究对象,采用序批式厌氧消化技术对污泥进行处理,利用超高液相色谱-串联质谱(LC-MS/MS)对泥样中8种抗生素进行检测分析,实时荧光定量PCR方法对四环素类抗性基因、磺胺类抗性基因及Ⅰ类整合子(intIl)进行定量分析,以探寻不同条件(温度、初始pH)对抗生素和抗性基因行为特征的影响,并分析营养元素、Ⅰ类整合子与抗性基因之间的相关性。以温度(15℃、30℃、36℃、、50℃、60℃)为实验变量,研究发现,抗生素的降解速率随温度的升高而升高,15℃、中温(30℃和36℃)和高温(50℃和60℃)下总抗生素的平均去除率分别为45%、59%和78%。温度升高对抗性基因的削减效果影响显著,15℃、中温(30℃,36℃)和高温(50℃,60℃)下四环素类抗性基因分别削减0.52 log、0.90 log和1.50 log,磺胺类抗性基因分别削减0.56 log、0.78 log和1.31 log。但反应50天时,tetM. tetO、tetQ、tetX、sulⅠ、 sulⅡ均出现回升,其中tetO回升最多,达0.84 log。以初始pH(3、5、7、9、11)为实验变量,结果显示,污泥中的部分抗生素得到削减,总抗生素的平均去除率为42%。初始pH变化对抗生素降解和抗性基因削减的影响很小。对照组及初始pH为3、5、7、9、11下的四环素类抗性基因分别削减0.65 log、0.96 log、0.75 log、0.62 log、0.86 log和0.98 log,其中在初始pH=3和初始pH=11下四环素类抗性基因削减较多。然而磺胺类抗性基因均无削减,浓度平均上升0.18 log。相关性分析表明,只有tetQ与营养元素呈负相关,其余抗性基因与其皆呈正相关。SCOD、NH3-N、TN和TP与tetM、tetX、su1Ⅱ皆无显著相关性,而与tetA、tetG、tetL、tetW皆存在显著相关性。intI1与其中的NH3-N、TN和TP存在显著相关性(R2=0.495、0.459、0.587,P0.05)。
[Abstract]:There is a high concentration of resistance genes in the excess sludge of sewage treatment plant, but there are few studies on the effective treatment of sludge to reduce its environmental risk. At present, it has been shown that anaerobic digestion technology can effectively reduce the resistance genes in sludge. Therefore, in this study, the excess sludge of municipal wastewater treatment plant was used as the main research object, the sludge was treated by sequencing batch anaerobic digestion, and 8 antibiotics in the sludge samples were detected and analyzed by ultra-high liquid chromatography-tandem mass spectrometry (LC-MS / MS). The quantitative analysis of tetracycline resistance genes, sulfonamides resistance genes and class I integron (int Il) by real-time fluorescence quantitative PCR was carried out to explore the effects of different conditions (temperature, initial pH) on the behavioral characteristics of antibiotics and resistance genes. The relationship between nutrient elements, class I integron and resistance gene was analyzed. Taking the temperature (15 鈩，

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