Dehghani M H, Jahed G R, Mesdaghinia A R, Nasseri S
Tehran University of Medical Sciences, School of Public Health, Department of Environmental Health Engineering, Tehran, IR Iran.
Environ Technol. 2008 Nov;29(11):1145-8. doi: 10.1080/09593330801984175.
This study was done to investigate the reduction of anaerobic bacteria (Clostridium perfringens) by ultrasound irradiation technology (USI). C. perfringens is the most important of the sulfite-reducing clostridia and is normally present in human and animal feces. Clostridial spores survive longer than coliforms, Escherichia coli or enterococci, and are consequently used as an indicator of past fecal pollution. The spores are not always inactivated by chlorination, but are not a hazard to health in potable water. C. perfringens are very resistant to chlorine and other drinking-water disinfectants. Conventional water treatment practices including chlorination are sometimes inadequate for inactivation of C. perfringens. Ultrasound irradiation is able to inactive C. perfringens through a number of physical and chemical effects arising from acoustic cavitation. The phenomenon of cavitation, which involves formation, growth, and violent collapse of vapour bubbles in a liquid media, is known to generate a high-intensity pressure, which affects the cell and C. perfringens' viability. Cavitations disrupt C. perfringens. Ultrasound irradiation at a frequency of 42 kHz was used to expose aqueous suspension of C. perfringens to evaluate the disinfection efficacy of ultrasound irradiation. Results indicated a significant increase in reduction of C. perfringens with increasing ultrasound time. C. perfringens was inactivated by 99.98% after 90 min.
本研究旨在探讨超声辐照技术（USI）对厌氧细菌（产气荚膜梭菌）的杀灭效果。产气荚膜梭菌是亚硫酸盐还原梭菌中最重要的一种，通常存在于人和动物粪便中。梭菌芽孢比大肠菌群、大肠杆菌或肠球菌存活时间更长，因此被用作过去粪便污染的指标。芽孢并不总是能被氯化灭活，但在饮用水中对健康无害。产气荚膜梭菌对氯和其他饮用水消毒剂具有很强的抗性。包括氯化在内的传统水处理方法有时不足以使产气荚膜梭菌失活。超声辐照能够通过声空化产生的多种物理和化学效应使产气荚膜梭菌失活。空化现象涉及液体介质中蒸汽泡的形成、生长和剧烈崩溃，已知会产生高强度压力，从而影响细胞和产气荚膜梭菌的活力。空化作用会破坏产气荚膜梭菌。使用42kHz频率的超声辐照处理产气荚膜梭菌的水悬浮液，以评估超声辐照的消毒效果。结果表明，随着超声处理时间的增加，产气荚膜梭菌的杀灭率显著提高。90分钟后，产气荚膜梭菌的灭活率达到99.98%。
