Can rapid pressure decrease induced by supercavitation efficiently eradicate Legionella pneumophila bacteria?

Abstract

The presence of Legionella pneumophila bacteria in engineered water systems can pose a significant health risk. Current prevention and outbreak treatments are cost and environmentally ineffective. Moreover they do not prevent rapid bacteria recolonization. Although cavitation was already suggested as a possible water treatment technique a systematic study has not yet been performed. In the present experimental campaign we set out to evaluate the efficiency of removal of L. pneumophila by three types of cavitation—the most commonly used acoustic cavitation, the aggressive developed hydrodynamic cavitation, and the supercavitation. We show that it is probably not the pressure peaks or the high local temperatures that cause the eradication of the bacteria, but the rapid pressure decrease which was initiated in supercavitating flow regime. Results of the study show promising ground for further optimization of a methodology for L. pneumophila removal by cavitation.

Keywords:

• Cavitation
• Legionella pneumophila bacteria
• Supercavitation
• Developed hydrodynamic cavitation
• Ultrasonic cavitation

Acknowledgment

The authors thank the Slovenian Research Agency which partially financially supported this work under the scope of a project J7-4265.