Methods of preparing antimicrobial-coated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

This work was done by James R. Akse, John T. Holtsnider, and Helen Kliestik of Umpqua Research Co. for Johnson Space Center. For more information, download the Technical Support Package (free white paper) at under the Manufacturing & Prototyping category. MSC-23468-1

NASA Tech Briefs Magazine

This article first appeared in the February, 2011 issue of NASA Tech Briefs Magazine.

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