Effectiveness of silver and copper infused ceramic drinking water filters in reducing microbiological contaminants

A series of bench-scale experiments were conducted on ceramic filters with various amounts of silver and/or copper nanoparticles fired-in during the manufacturing process. The experiments were designed to determine the efficacy of the filters on the removal of pathogens from drinking water. Escherichia coli and MS2 were employed as non-pathogenic surrogates for pathogenic organisms. Experiments were run on 23 ceramic filters – 10 replicates, one single filter, and two blanks – for approximately 10 days. Influent and effluent turbidity, E. coli, and MS2 concentrations were monitored regularly. Results showed that all ceramic filter configurations exceeded WHO standards for removal of bacteria under highly protective conditions, but few met these criteria for bacteriophage. The filters containing various concentrations of silver nanoparticles (25–100%) achieved an additional 2 log removal over the blank, copper, and mixed copper/silver filters for bacteria; however, it was difficult to determine the effect of nanoparticles on the removal of bacteriophage. A significant variation in effluent quality between filters of the same composition was observed, indicating the importance of variations in the manufacturing process on effluent water quality. Given the potential health risks of inadequate filtration, it is recommended that the quality control process be examined and upgraded.