Proceedings of the 18th International Congress of chemical and process engineering pages:1-9
International Congress of chemical and process engineering edition:18 location:Prague, Czech Republic date:24-28 August 2008
In this study, we investigated the use of ultrasound as an alternative for more traditional techniques like chlorination and UV irradiation for the disinfection of water. A pilot plant designed to compare traditional disinfection techniques with ultrasound was used to asses the potential benefits of using ultrasound in a closed loop configuration. The pilot plant consists out of four water containers with pumps to adjust the water flow, a piping system, a disinfection unit (chlorination, ultrasound or UV irradiation) and four biofilm monitors with 18 polycarbonate plates on which a biofilm can be formed. The disinfection efficiency of the different techniques is evaluated and the operational costs for the different techniques is assessed. Quantification of the number of bacteria is carried out with traditional plate counts on Brain Heart Infusion Agar. Water (100 l) inoculated with a bacterial suspension (105 CFU/ml) was treated in closed loop during 180 minutes with chlorination (0.2 mg/l free chlorine), UV irradiation (0.34 kWh) and ultrasound (0.85 kWh). Based on disinfection efficiency and operational cost the use of chlorination is, in comparison with UV irradiation and ultrasound, the most beneficial method to treat bacteria in suspension. In the treatment of larger volumes of contaminated water ultrasonic technology can not compare with the traditional techniques, partially due to a high energy demand. In the treatment of biofilm, the results of UV irradiation and ultrasound are comparable with a slightly higher energy consumption for the ultrasonic treatment.