Disinfection of water in a batch reactor using chloridized silver surfaces

There is growing interest in the use and development of silver based disinfection technologies owing to its safe and effective bactericidal action. The present work demonstrates the bactericidal effect of chloridized silver wires, where chloridization was achieved through chemical/electrochemical methods. The disinfection kinetics of uncoated and chloridized silver wires immersed in a 100 mL batch reactor were compared for one Gram positive and two Gram negative model bacterial strains, i.e., Bacillus subtilis MTCC 441 and Escherichia coli MTCC 443 and MTCC 739, respectively. Results showed that the chloridized silver wires could achieve better bactericidal effect compared to the uncoated silver wires. Initial cell concentration (N0) had a significant influence on the time required for complete disinfection which increased by more than 60 fold as N0 increased from 103 to 109 CFU/mL. The disinfection kinetics was correlated with release of silver ions from the chloridized surfaces and was affected by changes in water quality and presence of other constituents in water. High alkalinity showed minimal adverse effect whereas high values of hardness and natural organic matter had severe adverse effect on disinfection kinetics and silver release.