Inactivation of coliforms in sludge through cavitation phenomena by ultrasonic waves

Document Type : Original Article


1 Department of Environmental Engineering, Faculty of Environment, College of Engineering, University of Tehran, Tehran, Iran.

2 Department of Environmental Engineering, Faculty of Civil Engineering, Babol (Noshirvani) University of Technology, Babol, Iran.



Background: One of the most challenging and critical processes in wastewater treatment is sludge treatment. This study aims to investigate the low frequency effect of ultrasonic waves and the high level of energy to enhance the removal rate of total coliform of sludge and determine the optimum operating parameters of the ultrasonic waves.

Methods: In this research, variables are ultrasound density in watts per ml and time in minutes. Furthermore, the effect of these variables on the total coliform inactivation in sludge is measured.

Results: The results established that the optimum operating parameters were 30 minutes’ time, 2.5 W/ml of ultrasound density in the frequency of 20 kHz of Total coliform inactivation rate in these circumstances was 99.44 percent.

Conclusion: Based on the findings of this study, ultrasound waves and micro and nano bubbles could remove total coliform and disinfect the sludge and can increase the treatment rate.


Main Subjects