ASSESSING OZONE DISINFECTION WITH NONBIOLOGICAL SUROGATES

摘要

The authors investigated the use of fluorescent-dyed polystyrene microspheres to assess drinking water disinfection efficiency in full-scale ozone contactors. A demonstration was conducted with one of two parallel full-scale ozone bubble-diffuser contactors at the Alameda County Water District Water Treatment Plant in Fremont, Calif. Microsphere suspensions were analyzed by flow cytometry to determine changes in fluorescence distribution. Selection of threshold fluorescence intensities allowed the determination of microsphere " survival" ratios that were correlated with Cryptosporidium parvum inactivation curves. Compared with the concentration times contact time (C x T) concept, use of he surrogate indicatiors offered a potentially simpler and more accurate approach for assessing and optimizing ozone disinfection efficiency achieved in full-scale contactors and for demonstrating compliance with disinfection requirements.