Determining the effect of system parameters on ultrasonic water disinfection and enhancing its efficiency with a hybrid application

Abstract

Aim: The study was carried out to investigate the ultrasonic disinfection efficiency for water treatment, which is one of the most remarkable technologies among the new disinfection alternatives. Methodology: The disinfection of Escherichia coli, as an indicator microorganism of fecal pollution in water, was performed with ultrasound. Ultrasonic frequency, presence of dominant media ions (sulphate, nitrate and bicarbonate) at different concentrations and dissolved nitrogen gas at three flow rates were mainly investigated as system parameters in an ultrasonic batch type reactor. Hydrogen peroxide was used to enhance the ultrasonic disinfection efficiency over a shorter inactivation period at three different concentrations. Results: The highest Escherichia coli inactivation (5 log) occurred at 28 kHz frequency, and sulphate and bicarbonate ions accelerated the ultrasonic disinfection efficiency when increasing their concentration in water. In addition, while the nitrate ion had no significant effect on the ultrasound process, dissolved nitrogen gas increased the bacterial inactivation with increasing flow rates. In the hybrid disinfection application of ultrasound and hydrogen peroxide, increasing H2O, concentration provided more efficient bacterial inactivation over a shorter disinfection period. Interpretation: Disinfection with ultrasound and hydrogen peroxide was successfully performed in water treatment, and their hybrid application supplied more efficient bacterial inactivation over a shorter disinfection period due to their synergistic effect. [GRAPHICS] .