Evaluation of Antimicrobial Metals for Enhanced Performance of Household Water Treatment Methods Public Deposited

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  • March 20, 2019
  • Friedman, Katie
    • Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
  • Household water treatment and safe storage (HWTS) technologies play an increasingly important role in the reduction of global burden of waterborne disease, putting the capacity to treat unsafe drinking water directly into the hands of the consumer without reliance on centralized treatment or piped water systems. HWTS technologies differ in their ability to reduce viral, bacterial, and parasitic contaminants. Microbial reduction targets for HWTS performance set by the World Health Organization (WHO) are based on acceptable risk levels and log10 reductions. One approach to improve microbial reductions to meet performance targets is the incorporation of antimicrobial metals, which have been utilized for disinfection for centuries. The aim of this research was to evaluate copper, silver, and iron incorporated into ceramic water filters for improved E. coli and MS2 bacteriophage reductions and to determine the kinetics and magnitude of E. coli and MS2 inactivation with copper and silver ions as additives to water for solar disinfection (SODIS) and safe storage. The incorporation of copper, silver, and iron additives generally improved the reductions of E. coli by the ceramic water filters to reach the WHO Highly Protective (4 log10 reduction) target for bacteria, but viral reductions remained well below the WHO Protective (3 log10 reduction) target. Leached copper and silver ions in the filter effluent contributed to additional disinfection of E. coli and MS2 with overnight storage time. For stored water, copper and silver ions at concentrations allowable for drinking water showed the capacity to meet WHO Protective targets for virus reductions after overnight storage due to an apparent synergistic disinfection effect between copper and silver ions. Copper and silver ion additives also significantly increased the inactivation rates of bacteria and more notably viruses in SODIS. E. coli reductions were evaluated on selective and non-selective media, and differences in log10 reductions indicated the ability of E. coli to resuscitate initially after sub-lethal injury by metals and/or solar irradiation, but this effect decreased as exposure times increased. Incorporation of antimicrobial metal additives for ceramic water filters, SODIS, and stored water requires further study but shows promise for improved microbial reductions by HWTS technologies.
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Rights statement
  • In Copyright
  • Sobsey, Mark
  • Coronell, Orlando
  • Medema, Gertjan
  • Kolsky, Pete
  • Kasichainula, Jagannadham
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2018

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