Department of Civil and Environmental Engineering, Southern Methodist University, Suite 203, 3101 Dyer Street, Dallas, TX 75205, USA.
Water Res. 2011 May;45(11):3300-8. doi: 10.1016/j.watres.2011.03.034. Epub 2011 Mar 31.
The role of primary sludge particulates (PSPs) in ultrasonic disinfection of Escherichia coli (E. coli) was investigated. Entrapment of E. coli by PSP was directly observed through scanning electron microscope (SEM) after E. coli and PSP were incubated together in water for 24 h at 35 °C. Entrapment coefficient was proposed for the first time to reflect the ability of PSP to entrap E. coli and was estimated as 1.4 × 10(3) CFU/mg PSP under our experimental conditions. Ultrasonication (20 kHz) of different E. coli-PSPs solutions showed that the entrapped E. coli cells were protected by PSP from ultrasonication and the unentrapped cells were not. However, the protection of entrapped E. coli cells gradually decreased as ultrasonication proceeded, suggesting the ability of power ultrasonication to deprotect the entrapped E. coli cells. SEM studies suggested a two-step mechanism for ultrasonic (20 kHz) disinfection of entrapped E. coli: breakdown of the protective PSP refugia and disinfection of the exposed E. coli cells. This research will enable more informed decisions about disinfection of aqueous samples where porous PSP are present.
研究了原生污泥颗粒（PSP）在大肠杆菌（E. coli）超声消毒中的作用。通过在 35°C 下将 E. coli 和 PSP 在水中共同孵育 24 小时后，通过扫描电子显微镜（SEM）直接观察到 E. coli 被 PSP 捕获。首次提出了截留系数来反映 PSP 捕获 E. coli 的能力，在我们的实验条件下，截留系数估计为 1.4×10(3)CFU/mg PSP。对不同的 E. coli-PSP 溶液进行超声处理（20 kHz）表明，被 PSP 捕获的大肠杆菌细胞受到保护，而未被捕获的细胞则没有。然而，随着超声处理的进行，被捕获的大肠杆菌细胞的保护作用逐渐降低，这表明功率超声有能力解除被捕获的大肠杆菌细胞的保护。SEM 研究表明，被捕获的大肠杆菌的超声（20 kHz）消毒有一个两步机制：破坏保护性 PSP 避难所和暴露的 E. coli 细胞的消毒。这项研究将使人们能够更明智地决定在存在多孔 PSP 的水样品中进行消毒。
