The effect of ultrasonic waves on the amount of total coliform and E-coli in municipal wastewater sludge

Document Type : علمی - پژوهشی


1 Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran

2 Research Center for Environmental Pollutants and Department of Environmental Health Engineering, Qom University of Medical Sciences, Qom, Iran

3 Department of Environmental Engineering, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran


Introduction: Sludge treatment in wastewater treatment plants is one of the most difficult challenges for professionals and officials (Heidari et al., 2014). The most important indicator of the presence of pathogens in the sludge and wastewater is the presence of coliforms (Tchobanoglous et al., 2003; Metcalf & Eddy, 2003). Ultrasound waves at frequencies of 20 to 200 kHz with high levels of energy is one of the new methods for disinfection of water and wastewater treatment plants (Foladori et al., 2010; Show et al., 2007; Pilli et al., 2011). The purpose of this study is to determine the effect of ultrasonic waves with a low wavelength to improve removal rate of total coliform and Escherichia coli in sludge and determine the optimum operating parameters of the ultrasonic method.Materials and methods: This study is a cross-sectional study that was conducted in a laboratory-scale batch. Accordingly, during two seasons, 12 samples were taken at an interval of 15 days. In this research, variables include ultrasound density (0.375, 0.75, 1, 1.3 and 2.5) in watts on ml and time (1, 5, 10, 15 and 30) in minutes. In this research the influence of these variables on the total coliform and E coli of sludge is measured. The ultrasonic device used in this study was a probe with a maximum output power of 750 watts and frequency of 20 kHz. All bacteriological tests were conducted using the MPN method in a few steps of possibility, confirmation and completion and they were performed using 15 tube methods with units of MPN per 100 ml. All the experiments have done in the Nano, Water and Wastewater laboratory of the Department of the Environment at the University of Tehran. All the experiments were performed on the basis of standard methods for water and wastewater experiments with No. 9221 (APHA, 2005).Results and discussion: With ultrasonic waves and through the destruction of the cell walls of pathogens, viruses and microbes and the disintegration of pathogens result in the disinfection of sludge. The high temperatures caused by cavitation can also be locally led for the elimination of pathogens. It seems that the hydrodynamic force and local high temperature zones caused by the cavitation phenomenon are the most important mechanisms influencing sludge disinfection process through applying ultrasonic waves. The results of this study showed that removal of total coliform and E. coli increased with an increase in the time and ultrasound density. The experiments determined that the optimum operating parameters are a sonification time of 30 minutes, ultrasound density of 2.5 W/ml in a frequency of 20 kHz. The removal rate of total coliform and Escherichia coli under these circumstances was more than 99 percent which is equal to the removal of 2 logs.Conclusion: Based on the results of this research, ultrasound waves can remove coliform and disinfect the sludge and can increase the treatment rate. 


  1. Amin, M., Hashemi, H., Ebrahimi, A., Bina, B., Attar, H. and Jaberi, A., 2011. Using Combined Processes of Filtration and Ultraviolet Irradiation for Effluent Disinfection of Isfahan North Wastewater Treatment Plant in Pilot Scale. Wastewater journal. 22, 2, 71-77. (In Persian with English abstract)
  2. Antoniadis, A., Poulios, I., Nikolakaki, E. and Mantzavinos, D., 2007. Sonochemical disinfection of municipal wastewater. Journal of Hazardous Materials. 146, 492-495.
  3. APHA, 2005. Standard Methods for the Examination of Water and Wastewater, 21st ed. Washington: American Public Health Association/American Water Works Association/Water Environment Federation.
  4. Black & Veatch Corporation, 2010. White's Handbook of Chlorination and Alternative Disinfectants.
  5. Wiley. Blume, T. and Neis, U., 2004. Improved wastewater disinfection by ultrasonic pretreatment. Ultrason Sonochem. 11, 333–336.
  6. Bougrier, C., Carrere, H. and Delgenes, J., 2005. Solubilisation of waste-activated sludge by ultrasonic treatment. Chemical Engineering Journal. 106, 163-169.
  7. Brayman, A., MacConaghy, B., Wang, Y., Chan, K., Monsky, W., McClenny, A. and Matula, T., 2017. Inactivation of Planktonic Escherichia coli by Focused 2-MHz Ultrasound. Ultrasound in Medicine & Biology. 26 April 2017, In press.
  8. Dabbagh, R., 2009, Microbial Removal Efficiency of UV in Tehran Shahid Mahallati Wastewater Treatment Plant. Wastewater journal. 20, 1, 59-66. (In Persian with English abstract)
  9. Dehghani, M., 2005. Effectiveness of Ultrasound on the Destruction of E-coli. American Journal of Environmental Sciences. 1, 3, 187-189.
  10. Drakopoulou, S., Terzakis, S., Fountoulakis, M., Mantzavinos, D. and Manios, T., 2009. Ultrasound-induced inactivation of gram-negative and gram-positive bacteria in secondary treated municipal wastewater. Ultrasonics Sonochemistry. 16, 629-634.
  11. Foladori, P., Andreottola, G. and Ziglio, G., 2010. Sludge reduction technologies in wastewater treatment plants. IWA Publishing.
  12. Gholami, M., Mirzaei, R., Mohammadi, R., Zarghampour, Z. and Afshari, A., 2014. Destruction of Escherichia coli and Enterococcus faecalis using Low Frequency Ultrasound Technology: A Response Surface Methodology. Health Scope. 3, 1, e14213.
  13. Gottschalk, C., Libra, J. and Saupe, A., 2000. Ozonation of Drinking Water and of Wastewater. Wiley-Blackwell.
  14. Gottschalk, C., Libra, J. and Saupe, A., 2010. Ozonation of Water and Waste Water: A Practical Guide to Understanding Ozone and its Applications. Wiley-VCH.
  15. Hashemi, H., Amin, M., Ebrahimi, A., Rezaie, R. and Safari, M., 2012. Evaluation of health, environmental, economic and technical aspects of disinfection of WWTP effluent in the north of Isfahan with UV instead of chlorine. Wastewater journal. 16, 4, 71-77. (In Persian with English abstract)
  16. Heidari, A., Nabizadeh, R., Mohammadi, M., Gholami, M. and Mahvi, A., 2014. A survey on the effect of ultrasonic method on dewatering of bio sludge in wastewater treatment plant. Journal of Sabzevar University of Medical Sciences. 21, 3, 424-430. (In Persian with English abstract)
  17. Hulsmans, A., Joris, K., Lambert, N., Rediers, H., Declerck, P. and Delaedt, Y. 2010. Evaluation of process parameters of ultrasonic treatment of bacterial suspensions in a pilot scale water disinfection system. Ultrasonics Sonochemistry. 17, 1004–1009.
  18. Jin, X., Li, Z., Xie, L., Zhao, Y. and Wang T., 2013. Synergistic effect of ultrasonic pre-treatment combined with UV irradiation for secondary effluent disinfection. Ultrasonics Sonochemistry. 20, 6, 1384–1389.
  19. Jyoti, K. and Pandit, A., 2004. Effect of cavitation on chemical disinfection efficiency. Water Research. 18, 9-19.
  20. Mehrdadi, N., Nabi, G., Zahedi, A., Mohamadi, A. and Aghajani, A., 2013. Application of ultrasonic Wave irradiation in wastewater treatment, Tehran: University of Tehran Press. (In Persian with English abstract)
  21. Metcalf & Eddy., 2003. Wastewater Engineering Treatment and Reuse. 4th ed. McGraw-Hill Inc.
  22. Mohammadi, A., Mehrdadi, N., Nabi, G. and Torabian, A., 2011. Excess sludge reduction using ultrasonic waves in biological wastewater treatment. Desalination. 275, 1-3, 67-73.
  23. Naddeo, V., Landi, M., Belgiorno, V. and Napoli, R., 2009. Wastewater disinfection by combination of ultrasound and ultraviolet irradiation. Journal of Hazardous Materials. 168, 925-92.
  24. Neis, U. and Blume, T., 2011. The Effect of Ultrasound on Particulate Matter, Especially Microorganisms in Complex Water and Waste Water Media. Environmental Proggress & Sustainability. 25, 3, 257-260.
  25. Pilli, S., Bhunia, P., Yan, S., LeBlanc, R., Tyagi, R. and Surampalli, R., 2011. Ultrasonic pretreatment of sludge: A review. Ultrasonics Sonochemistry. 18, 1-18.
  26. Shahmansouri, M. and Kargar, M., 2005. fficiency of Ozonation in Decreasing Total Organic Carbon and Total Coliform Bacteria in Isfahan Water Treatment Plant. Wastewater journal. 16, 2, 43-46. (In Persian with English abstract)
  27. Show, K., Mao, T. and Lee, D., 2007. Optimisation of sludge disruption by sonication. Water Research. 41, 4741 – 4747.
  28. Tchobanoglous, G., Burton, F. and Stensel, H., 2003. Wastewater engineering treatment & reuse. McGraw-Hill.
  29. Schlafer, O., Sievers, M., Klotzbucher, H. and Onyeche, T., 2000. Improvement of biological activity by low energy ultrasound assisted bioreactors. Ultrasonics. 38, 711-716.
  30. Yan, Y., Feng, L., Zhang, C., Wisniewski, C. and Zhou, q., 2010. Ultrasonic enhancement of waste activated sludge hydrolysis and volatile fatty acids accumulation at pH 10.0. Water research. 44, 3329-3336.
  31. Zhang, G., Zhang, P., Yang, J. and Liu, H., 2008. Energy-efficient sludge sonication: Power and sludge characteristics. Bioresource Technology. 99, 9029-9031.
  32. Zhou, X., Yan, Y., Li, Z. and Yin, J., 2017. Disinfection effect of a continuous-flow ultrasound/ultraviolet baffled reactor at a pilot scale. Ultrasonics Sonochemistry. 37, 114–119.