92-13: Biocide Efficacy vs. Acid Producing and Iron Oxidizing Bacteria

Procedures have been developed for the successful evaluation of four water treatment biocides versus the acid-producing bacteria Thiobacillus novellas and the iron oxidizing bacteria Leptotrhix discophoro, Hyphomicrobium indicium and Sphaerotilis natans. The evaluations were conducted at pH 7.0 and ambient temperature. Each biocide was tested at concentrations that represent recommended treatment dosages for industrial water systems. The Biocidal efficacy was evaluated after a 1, 4, and 7-hour contact time with the organisms. All of the biocides proved to be highly effective against L. discophora, whereas efficacy against T. novellas, H. indicium and S. natans varied.