Photocatalysis Research Group, Nanotechnology and Integrated BioEngineering Centre, University of Ulster, Northern Ireland, United Kingdom.
Chemosphere. 2011 Nov;85(7):1160-6. doi: 10.1016/j.chemosphere.2011.09.006. Epub 2011 Oct 7.
Solar disinfection (SODIS) of Escherichia coli suspensions in low-density polyethylene bag reactors was investigated as a low-cost disinfection method suitable for application in developing countries. The efficiency of a range of SODIS reactor configurations was examined (single skin (SS), double skin, black-backed single skin, silver-backed single skin (SBSS) and composite-backed single skin) using E. coli suspended in model and real surface water. Titanium dioxide was added to the reactors to improve the efficiency of the SODIS process. The effect of turbidity was also assessed. In addition to viable counts, E. coli injury was characterised through spread-plate analysis using selective and non-selective media. The optimal reactor configuration was determined to be the SBSS bag (t(50)=9.0min) demonstrating the importance of UVA photons, as opposed to infrared in the SODIS disinfection mechanism. Complete inactivation (6.5-log) was achieved in the presence of turbidity (50NTU) using the SBSS bag within 180min simulated solar exposure. The addition of titanium dioxide (0.025gL(-1)) significantly enhanced E. coli inactivation in the SS reactor, with 6-log inactivation observed within 90min simulated solar exposure. During the early stages of both SODIS and photocatalytic disinfection, injured E. coli were detected; however, irreversible injury was caused and re-growth was not observed. Experiments under solar conditions were undertaken with total inactivation (6.5-log) observed in the SS reactor within 240min, incomplete inactivation (4-log) was observed in SODIS bottles exposed to the same solar conditions.
采用低密度聚乙烯袋式反应器，对大肠杆菌悬浮液进行太阳消毒（SODIS），作为一种适合发展中国家应用的低成本消毒方法进行了研究。采用模型水和实际地表水悬浮的大肠杆菌，考察了一系列 SODIS 反应器结构的效率（单层（SS）、双层、黑背单层、银背单层（SBSS）和复合背单层）。向反应器中添加了二氧化钛，以提高 SODIS 工艺的效率。还评估了浊度的影响。除了活菌计数外，还通过使用选择性和非选择性培养基的平板扩散分析来表征大肠杆菌的损伤。确定最佳的反应器结构是 SBSS 袋（t(50)=9.0min），这表明在 SODIS 消毒机制中，UVA 光子而非红外线更为重要。在存在浊度（50NTU）的情况下，使用 SBSS 袋在 180min 模拟太阳照射下即可实现完全灭活（6.5-log）。在 SS 反应器中添加 0.025gL(-1)的二氧化钛显著增强了大肠杆菌的灭活，在 90min 模拟太阳照射下观察到 6-log 的灭活。在 SODIS 和光催化消毒的早期阶段，检测到受伤的大肠杆菌；然而，会造成不可逆转的损伤，并且不会观察到再生长。在太阳条件下进行了实验，在 240min 内观察到 SS 反应器中的总灭活（6.5-log），而在相同的太阳条件下暴露的 SODIS 瓶中则观察到不完全灭活（4-log）。
