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AWWA ACE54459
- Inactivation of Cryptosporidium parvum Oocysts in Drinking Water by High-Intensity Ultrasonic Waves
- Conference Proceeding by American Water Works Association, 06/01/2001
- Publisher: AWWA
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The possibility of the inactivation of Cyrptosporidium parvum oocysts by high-intensity ultrasonic waves at frequencies of 28, 45, and 100 kHz was examined. Oocysts in a flat-bottomed reactor were treated in batches. The oocysts were observed under a microscope in one test of inactivation, and also were tested for their ability to infect mice. After treatment, some oocysts had breaks in their walls, through which the nucleus had leaked. The proportion of such oocysts in a preparation was related to the degree of infectivity of the preparation. The lowest frequency, 28 kHz, was most effective in inactivating oocysts. With 10 minutes of treatments, 97% of the oocysts had ruptured, and infectivity was less than 1% of the base line. With longer treatment, inactivation was greater. The mechanism of inactivation of oocysts by high-intensity ultrasonic waves in this experiment seemed to involve cavitation. Includes 6 references, figures.