Inactivation of bacteria and murine norovirus in untreated groundwater using a pilot-scale continuous-flow intense pulsed light (IPL) system

Abstract

The objective of this study was to characterize the inactivation effects of a pilot-scale continuous-flow intense pulsed light (IPL) system on microorganisms in untreated groundwater used in the food industry. The inactivation effects of laboratory- and pilot-scale IPL systems on murine norovirus (MNV), a human norovirus surrogate, were also investigated. Flow rates of 40, 32, 20 and 12 l/min were tested (corresponding to 89,113, 179, and 290 s of treatment time in a chamber, respectively). A 290-s pilot-scale IPL treatment at an energy dose of 14.02 J/cm(2) resulted in a 4.79-log reduction of Escherichia coli C600 in water with an initial count of 10(5)-10(6) CFU/ml, while a 270-s treatment at an energy dose of 13.05 J/cm(2) resulted in a 2.91-log inactivation of aerobic and facultative anaerobic heterotrophs in untreated groundwater with the initial count of 4.5 x 10(4) CFU/ml. An 89-s treatment at a dose of 4.30 J/cm(2) resulted in a 3.35-log inactivation of MNV in water with the initial count of 10(3)-10(4) PFU/ml. The energy dose and the inactivation level showed linearity for this system. These trends should form the basis of a large-scale IPL-based water management system with improved energy efficiency. (C) 2015 Elsevier Ltd. All rights reserved.