Deploying Elemental Iodine in a Vapor Form to Disinfect Water and to Clear Biofilms

Traditionally, iodine has been delivered as a solution, tablet or resin to disinfect water. In this study we evaluated the "I₂ vapor infusion" (I₂VP) technology which passes an airstream through a matrix containing elemental iodine (I₂) to produce I₂ vapor as an innovative method of iodine delivery for water disinfection. Pressured air was provided either by a compressor or hand pump. Testing was performed with water inoculated with either Gram-negative (Escherichia, Salmonella) or Gram-positive (Enterococcus) bacteria or with pre-formed Acinetobacter or Staphylococcus biofilms. Bacterial colony forming units were used to assess efficacy of the device. In distilled water all bacteria and biofilms were eliminated after brief exposures (<90 s). Culturable bacteria were also eliminated from pond and municipal sewer water, but the technology was mostly ineffective against dairy lagoon water with high turbidity and organic particulate. Longer duration infusion and higher air volumes used to overcome interference from organic matter were also associated with higher concentrations of residual iodine. We conclude that I₂ vapor infusion has the potential to be useful for emergency water treatment and potentially for reducing microbiological contamination of some waste streams.