超声灭活饮用水中隐孢子虫研究

为研究超声对饮用水中隐孢子虫(Cryptosporidium parvum)的灭活情况,考察了超声频率、功率、pH值和温度对灭活率的影响,通过形态学观察初步探讨了超声灭活隐孢子虫的机制,并进行了灭活动力学分析.结果表明,低频有利于隐孢子虫灭活,19.8kHz, pH7.2,温度(20±1)℃条件下超声15min灭活率可达92.5%,频率升高灭活率反而下降.在本实验条件下,超声功率103W对隐孢子虫的灭活效果与151W的相近,pH值对超声灭活隐孢子虫的影响不大,36℃超声灭活15min灭活率为95.6%,而在9℃下超声15min灭活率为88.3%,水温升高有利于灭活.灭活前后的形态学变化表明超声空化作用导致细胞膜破坏,细胞质流出从而起到灭活孢囊的效果.超声灭活隐孢子虫遵循假一级反应动力学,灭活隐孢子虫以低频率高功率的效果最好,可认为隐孢子虫的灭活以超声空化的强度为主.

Inactivation of Cryptosporidium parvum in drinking water by ultrasonic irradiation

Ultrasonic on inactivation of Cryptosporidium parvum was studied under different operational parameters, such as ultrasonic frequency, ultrasonic power, pH and temperature. The mechanism of inactivation of Cryptosporidium parvum was preliminary discussed by morphological observation, and inactivating kinetic analysis was also focused. The results indicated that low frequency favored the inactivation of Cryptosporidium parvum, 92.5% of inactivating rate could be achieved under the condition of 19.8kHz ultrasonic (15min), pH 7.2and temperature 20±1℃, while the inactivating rate decreased if the frequency increased. Furthermore, the inactivating rates were almost the same regardless of ultrasonic power was 103W or 151W, and the value of pH had slight effect on inactivating. The inactivating rate was 95.6% using ultrasonic treatment for 15min at 36℃ while 88.3% at 9℃, which indicated higher temperature was conducive to the inactivation of Cryptosporidium parvum. Ultrasonic cavitation caused cell membrane damage and cytoplasm outflow in inactivating Cryptosporidium parvum. Ultrasonic inactivation of Cryptosporidium parvum was in line with pseudo-first-order kinetics, and lower frequency and higher power lead to better ultrasonic cavitation. Therefore, it was suggested that the intensity of ultrasonic cavitation was the main factor for inactivating Cryptosporidium parvum.