Huang Jing-Jing, Xi Jinying, Hu Hong-Ying, Li Yi, Lu Sun-Qin, Tang Fang, Pang Yu-Chen
State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China; China Power Engineering Consulting Group Co., LTD., Beijing 100120, China.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China.
J Environ Sci (China). 2016 Mar;41:146-153. doi: 10.1016/j.jes.2015.04.034. Epub 2015 Sep 2.
Tetracycline-resistant bacteria (TRB) are of concern as emerging microbial contaminants in reclaimed water. To understand the effects of UV disinfection on TRB, both inactivation and reactivation profiles of TRB, as well as 16 tetracycline-resistant isolates from secondary effluent, were characterized in this study. The inactivation ratio of TRB was significantly lower (3.0-log) than that of heterotrophic bacteria (>4.0-log) in the secondary effluent. Additionally, the proportion of TRB significantly increased from 1.65% to 15.51% under 20mJ/cm(2) ultraviolet (UV) exposure. The inactivation rates of tetracycline-resistant isolates ranged from 0.57/s to 1.04/s, of which tetracycline-resistant Enterobacter-1 was the most tolerant to UV light. The reactivation of TRB, tetracycline-resistant isolated strains, as well as heterotrophic bacteria commonly occurred in the secondary effluent even after 20mJ/cm(2) UV exposure. The colony forming ability of TRB and heterotrophic bacteria reached 3.2-log and 3.0-log under 20mJ/cm(2) UV exposure after 22hr incubation. The final inactivation ratio of tetracycline-resistant Enterobacter-1 was 1.18-log under 20mJ/cm(2) UV exposure after 22hr incubation, which is similar to those of TRB (1.18-log) and heterotrophic bacteria (1.19-log). The increased proportion of TRB and the reactivation of tetracycline-resistant enterobacteria in reclaimed water could induce a microbial health risk during wastewater reuse.
耐四环素细菌（TRB）作为再生水中新出现的微生物污染物备受关注。为了解紫外线消毒对TRB的影响，本研究对TRB的灭活和再激活情况以及二级出水的16株耐四环素分离株进行了表征。二级出水中TRB的灭活率（3.0个对数）显著低于异养细菌（>4.0个对数）。此外，在20mJ/cm²紫外线照射下，TRB的比例从1.65%显著增加到15.51%。耐四环素分离株的灭活率在0.57/s至1.04/s之间，其中耐四环素肠杆菌-1对紫外线耐受性最强。即使在20mJ/cm²紫外线照射后，二级出水中的TRB、耐四环素分离菌株以及异养细菌仍普遍发生再激活。在20mJ/cm²紫外线照射下培养22小时后，TRB和异养细菌的菌落形成能力分别达到3.2个对数和3.0个对数。在20mJ/cm²紫外线照射下培养22小时后，耐四环素肠杆菌-1的最终灭活率为1.18个对数，与TRB（1.18个对数）和异养细菌（1.19个对数）相似。再生水中TRB比例的增加和耐四环素肠杆菌的再激活可能会在废水回用过程中引发微生物健康风险。
