Performance and Cost-Effectiveness of Ferric and Aluminum Hydrous Metal Oxide Coating on Filter Media to Enhance Virus Removal

Abstract

Coating sand and granular activated carbon with iron aluminum hydroxides changed the zeta potential of these filtration media from negative to positive at pH 6–9, while also significantly improving removal of viruses (MS2, PRD1, Polio1). A quaternary ammonium based coating on sand also increased zeta potential, but led to limited improvement in virus removal. The coated activated carbon was effective in both columns and faucet filters. Performance of faucet filters decreased slightly (e.g., 98% removal initially vs. 89% removal after 1 month) with time. The chemical costs of coating would add approximately 10% to the cost of water delivered by large-scale municipal systems, whereas coating chemical costs would add less than 1% to the cost of water treated by point-of-use faucet filters. The improvement in virus removal performance gained by use of coated filter media provides a significant benefit to the consumer in terms of increased microbiological quality at a modest-to-negligible increase in cost.