Biocidal Efficacy of a Flocculating Emergency Water Purification Tablet

Edmund M. Powers,1* C. Hernandez,1 S. N. Boutros,2 and B. G. Harper3

1U.S. Army Natick Research, Development and Engineering Center, Natick, Massachusetts 01760-5018
2Environmental Associates, Ithaca, NY 14850
3Material Test Directorate, U.S. Army Dugway Proving Ground, Dugway, Utah 84022-5000

Chlor-Floc (CF) emergency water purification tablets were tested for bactericidal, virucidal, and cysticidal efficacy in water at temperatures ranging from 5 to 25°C. The minimal required log reduction was achieved for bacteria, Giardia muris, and rotavirus, but CF did not achieve the required log reduction of poliovirus at any of the temperatures or times investigated. The biocidal properties of the CF tablet were equivalent to if not greater than those of the Globaline iodine tablet, and the CF tablet was a more rapid cysticide under several potential use conditions. Therefore, it is a suitable substitute for iodine tablets for emergency purification of drinking water. Clarification of turbid waters was effective, but filtration through a cloth is necessary to prevent flocculated sediment from entering the canteen. The CF tablets met military requirements for emergency water purification and are safe and acceptable for use by the military.