Inactivation of Edwardsiella tarda and Vibrio harveyi by Chlorination in Seawater

Edwardsiella tarda ( E. tarda ) and Vibrio harveyi ( V. harveyi ), common pathogenic bacteria in fish, contribute to elevated mortality rates within fish populations. Chlorination, a widely utilized disinfection method, can effectively manage these microorganisms. The present research examined the impact of chlorination in the inactivation of two microorganisms, with varying pH, chlorine doses, natural organic matter (NOM) concentrations, and temperatures. Microbial inactivation during seawater chlorination is strongly influenced by the formation of chlorine-produced oxidants (CPOs), whose speciation was determined by pH, and concentrations of bromide ions and ammonium ions. At pH 7.1, mixed CPOs (mainly HOBr/NH x Br y /NHBrCl) were formed, while NH 2 Cl was the dominant species at pH 8.2. The higher inactivation efficacies at pH 7.1 compared with those at pH 8.2 were explained by the st…