Inactivation efficiency of silver ions-UV combined disinfection on domestic hot water microorganisms

Effect of silver ions, silver ions-UV combined disinfection on microbes was investigated by using a domestic hot water biofilm annular reactor. The results showed that silver ion dosage had a significant effect on the inactivation of microbes. The disinfection by 0.05mg/L silver ion achieved excellent microbial inactivation effect in 60min. Low dosage of silver ion had the same disinfection efficiency when the sterilization time was increased. The inactivation rate of Escherichia Coli by silver ion was low. Hence, adequate concentration and disinfection (CT) value need to be ensured. The concentration of silver ions attenuated slowly, resulting in high-efficiency inactivation ratio above 48h. Moreover, the significant damage to the biofilm structure was caused by all three disinfection method in a very short period. Among them, UV disinfection had the least effect on biofilm structure, while silver ion-UV combined disinfection had the greatest effect on biofilm structure. It was demonstrated by 16s rDNA approaches that the sterilization ratio of silver ions to pathogenic microorganism was relatively low and the sterilization ratio of UV and silver ion-UV combined disinfection was relatively high on the contrary. Therefore, silver ion-UV combined disinfection possessing the advantages of both UV disinfection and silver ion disinfection, comprehensively improves the domestic hot water biofilm microbial disinfection efficiency, which is a valuable technology for domestic hot water disinfection. © 2017, Editorial Board of China Environmental Science. All right reserved.