EFFECTS OF SUNLIGHT AND SALINITY INACTIVATION ON THE FATE OF FECAL INDICATOR MICROORGANISMS IN RAW SEWAGE

Effects of sunlight and salinity inactivation on the fate of three types of fecal indicator bacteria (E. coli, Fecal coliform, and Enterococcus) and two types of potential viral indicators (F-specific bacteriophage and Somatic coliphage) in raw sewage were examined by laboratory experiments. F-specific bacteriophage was inactivated by salinity and the inactivation was accelerated by sunlight, and E. coli, Fecal coliform, and Enterococcus were inactivated by sunlight. The overall sunlight inactivation coefficient (kI) ranking was as follows: E. coli > Fecal coliform > Enterococcus > F-specific bacteriophage. Somatic coliphage was not inactivated by salinity or sunlight. Furthermore, E. coli and Fecal coliform also exhibited a synergistic inactivation effect by salinity and sunlight. The significance of analyzing multiple indicators for understanding fecal pollution was found because the resistance of each indicator to salinity and sunlight was different.