Feasibility study of ultrasound as water disinfection technology

Abstract

This article presents a section of project work related to the use of ultrasound technology as an eco-friendly water disinfection process. Scientific and economical evaluations are presented for two different ultrasound systems. The effects of ultrasound frequencies (20, 279 and 817 kHz), amplitude (acoustic power) and the treatment time for bacteria survival were studied. Experiments performed on a laboratory scale using two biological indicator micro-organisms Bacillus subtilis and Escherichia coli indicated that disinfection efficiency is affected by bacteria morphology, ultrasound frequencies and energy densities entering the system. As the spore-forming bacteria B. subtilis seemed less vulnerable to ultrasound exposure, a significant E. coli inhibition of 2.97 ± 0.58 log was achieved in 5 min treatment time at 817 kHz.

Keywords:

• Ultrasound
• Disinfection
• Microbiology
• Escherichia coli
• Bacillus subtilis

Acknowledgement

Research was conducted within the AquaFit4Use, 7 FP European Project [211534]. Part of the microbiological research performed together with project partner Veolia from France.