中文摘要：

为了探讨超声波灭菌作用机制,进一步为超声波用于净水厂污泥无害化处理提供技术支持,试验采用实验室模拟水样,研究了超声功率（250~1 500 W）、频率（25 k Hz和40 k Hz）对大肠菌群灭活效果、超声空化强度和羟基自由基产量的影响.结果表明：相同时间和频率下,在超声功率为250~1 500 W时,大肠菌群灭活率随着功率的增大先逐渐上升,达到1 250 W后,灭活效果变化不明显;相同时间和功率条件下,40 k Hz灭活效果优于25 k Hz.超声空化强度和羟基自由基的产量与灭活率规律相似,超声灭活率随着超声过程中超声空化强度和羟基自由基产量的增大而增大.通过投加自由基掩蔽剂碳酸氢钠（Na HCO3）掩蔽自由基氧化作用判定羟基自由基在超声灭菌过程中的确产生了灭活作用,但作用比较弱.

英文摘要：

To discuss the mechanism of ultrasonic sterilization and provide technical support for the ultrasonic treatment for sludge disposal,the effects of ultrasound power（ 250-1 500 W） and frequencies（ 25 and 40 k Hz） on the inactivation rate of coliform,cavitation intensity and production of hydroxyl radicals were investigated with the simulated aqueous solution. The mechanism of inactivation was preliminarily discussed. Results showed that under the same ultrasound time and frequency, the inactivation rate of coliform gradually increased with the increases of ultrasound power lower than 1 250 W and then almost the same. The frequency of 40 k Hz showed more superiority than 25 k Hz under the same ultrasound time and power. Cavitation intensity and production of hydroxyl radicals displayed similarity as the inactivation rate did,therefore,the inactivation rate increased with the increases of cavitation intensity and production of hydroxyl radicals. Although the effect of hydroxyl radicals was weak,the oxidation of hydroxyl radicals did play a role in the sterilization that was identified by adding masking agents of sodium bicarbonate（ Na HCO3） into the simulated water.