Comparison of disinfection effect of pressurized gases of CO₂, N₂O, and N₂ on Escherichia coli

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• 作者：Huy Thanh Vo ; Tsuyoshi Imai ; Jantima Teeka ; Masahiko Sekine ; Ariyo Kanno ; Tuan Van Le ; Takaya Higuchi ; Kanthima Phummala ; Koichi Yamamoto
• 关键词：Escherichia coli ; Nitrous oxide ; High pressure CO2 ; Bactericidal effect ; Water disinfection
• 刊名：Water Research
• 出版年：2013
• 出版时间：1 September, 2013
• 年：2013
• 卷：47
• 期：13
• 页码：4286-4293
• 全文大小：1577 K

文摘

Based on the production of gas bubbles with the support of a liquid film-forming apparatus, a device inducing contact between gas and water was used to inactivate pathogens for water disinfection. In this study, the inactivation effect of CO₂ against Escherichia coli was investigated and compared with the effects of N₂O and N₂ under the same pressure (0.3-0.9?MPa), initial concentration, and temperature. The optimum conditions were found to be 0.7?MPa and an exposure time of 25?min. Under identical treatment conditions, a greater than 5.0-log reduction in E. coli was achieved by CO₂, while 3.3 log and 2.4 log reductions were observed when N₂O and N₂ were used, respectively. Observation under scanning electron microscopy and measurement of bacterial cell substances by UV-absorbance revealed greater cell rupture of E. coli following treatment with CO₂ than when treatment was conducted using N₂O, N₂ and untreated water. The physical effects of the pump, acidified characteristics and the release of intracellular substances caused by CO₂ were bactericidal mechanism of this process. Overall, the results of this study indicate that CO₂ has the disinfection potential without undesired by-product forming.