The Sonochemistry Centre, Faculty of Health and Life Sciences, Coventry University , Priory Street, Coventry CV1 5FB, U.K.
Environ Sci Technol. 2015 Oct 6;49(19):11697-702. doi: 10.1021/es5045437. Epub 2015 Sep 10.
The aim of this study is to assess the synergetic effect of combined ultrasound and ozone treatment on the biological disinfection of water on a large-scale application using viable plate counts and flow cytometry. Escherichia coli B bacteria in saline suspension was treated using a commercially available combined ultrasound and ozone system (USO3 (Ultrasonic Systems Gmbh)) for 16 min. Two analytical methods were used to assess the results in terms of live and dead cells in the bulk liquid: standard viable plate counting recorded in terms of colony forming units per milliliter and flow cytometry. In the latter case 1 mL of bacterial suspension was stained simultaneously with the fluorescent stains SYTO9 and propidium iodide (PI). Transmission electron microscopy was used to generate images identifying the biological effects of different treatments using ultrasound and ozone on bacterial cell walls. Results demonstrated that treatment with ozone alone (1 mg/L) resulted in a significant reduction (93%) in the number of live cells after 16 min treatment whereas ultrasound alone showed only a small reduction (24%). However, a combination of ozone and ultrasound showed a synergistic effect and enhanced the inactivation to 99% after 4 min. A combined ultrasound and ozone treatment of bacterial suspensions using a commercial system affords a promising method for water disinfection that is better than treatment using either method alone. Standard viable plate count analysis is normally used to assess the effectiveness of disinfection treatments; however flow cytometry proved to be a more sensitive method to determine the actual effects in terms of not only live and dead cells but also damaged cells. This type of analysis (cell damage) is difficult if not impossible to achieve using traditional plate counting methodology.
本研究旨在评估联合超声和臭氧处理对大型应用中生物消毒水的协同效应，使用活菌平板计数和流式细胞术进行评估。用市售的联合超声和臭氧系统（USO3（Ultrasonic Systems Gmbh））对生理盐水悬浮液中的大肠杆菌 B 菌进行处理 16 分钟。使用两种分析方法评估批量液体中活细胞和死细胞的结果：以每毫升形成单位数记录的标准活菌平板计数和流式细胞术。在后一种情况下，用荧光染料 SYTO9 和碘化丙啶（PI）同时对 1 毫升细菌悬浮液进行染色。透射电子显微镜用于生成图像，识别不同处理方法（单独使用臭氧和超声）对细菌细胞壁的生物效应。结果表明，单独使用臭氧（1mg/L）处理 16 分钟后，活细胞数量显著减少（93%），而单独使用超声仅减少（24%）。然而，臭氧和超声联合使用显示出协同效应，在 4 分钟后将失活率提高到 99%。使用商业系统对细菌悬浮液进行联合超声和臭氧处理提供了一种有前途的水消毒方法，优于单独使用任何一种方法。标准活菌平板计数分析通常用于评估消毒处理的效果；然而，流式细胞术被证明是一种更敏感的方法，可以确定不仅是活细胞和死细胞，还有受损细胞的实际效果。如果不是不可能的话，这种类型的分析（细胞损伤）很难使用传统的平板计数方法来实现。
