Inactivation of Escherichia coli by sonication at discrete ultrasonic frequencies

• Published in: Water research (Oxford) 2000-10, Vol.34 (15), p.3888-3893
• Main Authors: Hua, Inez, Thompson, John E
• Format: Article
• Language: English
• Subjects: Applied sciences; argon; DISINFECTION; Drinking water and swimming-pool water. Desalination; ENVIRONMENTAL SCIENCES; ESCHERICHIA COLI; Exact sciences and technology; FREQUENCY; germicide; INACTIVATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Pollution; SONOCHEMISTRY; ULTRASONIC; ULTRASONIC WAVES; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(00)00121-4

The sonolytic inactivation of Escherichia coli ( E. coli) is reported. The impact of power intensity, dissolved gas and ultrasonic frequency on the germicide effectiveness of sonification has been explored. The inactivation of E. coli exhibits pseudo-first order behavior, and depends moderately on total power and power intensity at a frequency of 20 kHz. The rate coefficients in an oxygenated solution vary from 0.031 to 0.046 min −1 when the power intensity ranges from 4.6 to 74 W cm −2. Inactivation occurs most readily at the highest sound intensity, 74 W cm −2. Three dissolved gases were investigated: oxygen, argon, and an argon/oxygen mixture. The nature of the dissolved gas does not strongly influence the magnitude of the inactivation coefficients which varied from k=0.027 min −1 to 0.047 min −1. Ultrasonic frequency, within the limits of 205–1017 kHz, displays a strong influence on the rate of E. coli inactivation in oxygenated solutions. The rate coefficients vary from 0.030 to 0.078 min −1. The most effective ultrasonic frequency for E. coli innovation is 205 kHz; the rate coefficient ( k=0.078 min −1) is greater than the coefficient at 1071 kHz ( k=0.030 min −1) by a factor of 2.6 and 358 kHz ( k=0.064 min −1) also demonstrates a greater efficiency than either 618 kHz ( k=0.041 min −1) or 1017 kHz.