Disinfection of Gram - Negative and Gram - Positive Bacteria using DYNAJETS ®

Cavitating jet nozzles (DYNAJETS ® ) were investigated as a means of disinfection of gram-negative E. coli, Klebsiella pneumoniae, Pseudomonas syringae, and Pseudomonas aeruginosa, and gram-positive Bacillus subtilis. The cavitating jets were found to be very effective in reducing the concentrations of all of these species. In general, the observed rates of disinfection of gram-negative species were higher than for gram-positive species. However, different gram-negative species also showed significant differences (P. syringae 6- log10 reduction, P. aeruginosa 2-log10 reduction) under the same conditions. Disinfection of E. coli repeatedly showed 5 orders of magnitude reduction in concentration within 45 to 60-minutes at low nozzle pressure (2.1 bar). Optimization of nozzle design and operating pressures increased disinfection rates per MJ of power by several orders of magnitude. The power efficiencies of the hydrodynamic cavitating jets were found to be 10 to 100 times greater than comparable ultrasonic systems.