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

Petronella R Hove,Daniel Mobley,Douglas R Call,Forgivemore Magunda

doi:10.3390/ijerph17103489

Abstract

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.

Highlights

Unclean drinking water is an important source of pathogenic bacteria, viruses and protozoan parasites for 2.7 billion people worldwide, underscoring the need for innovative safe and effective water disinfecting methods [1]
The same principle is used in the formulation of iodinated biocides where the degree of disinfection is determined by the availability and regulated release of free elemental iodine [21]. Based on these characteristics of iodine, we propose that presentation of elemental iodine in an un-complexed form coupled to a delivery method that maximizes distribution and interaction with the target microbes would offer significant and rapid antimicrobial activity in a fluid
When ambient air was infused without iodine, bacterial counts were within 0.2 log cfu mL−1 of the estimated inoculum value

Summary

Introduction

Unclean drinking water is an important source of pathogenic bacteria, viruses and protozoan parasites for 2.7 billion people worldwide, underscoring the need for innovative safe and effective water disinfecting methods [1]. Current methods of water disinfection broadly include physical or chemical treatment. Among the well-known chemical disinfectants are halogens, which include bromine, fluorine, chlorine and iodine. [2,3] Of these iodine has been widely used because it is generally effective, simple, cost-efficient and its properties for water disinfection are well known [4]. Relative to other halogens, complexed iodine has greater chemical stability [7]. It is less reactive with organic nitrogenous contaminants and can be retained at a higher residual concentration in water [7]

Results

Discussion

Conclusion