【国外标准】 Standard Test Method for Total Active Biomass in Cooling Tower Waters (Kool Kount Assay; KKA)

5.1 This test method is useful for rapid determination of viable active biomass concentrations in cooling tower waters. The efficiency of cooling towers is directly affected by the concentration of biomass in the cooling tower waters. As biomass concentrations increase, biofilm formation occurs resulting in a decrease in the efficiency of heat exchange in the tower. Current tests for monitoring the biomass concentration in cooling towers require at least 36 h for growth of the microorganisms on a solid agar surface for counting. Replication of microorganisms over the 36-h period before results are available creates an aqueous environment which is no longer represented by the data generated. Timely test results can assist in minimizing biocide addition to control biomass concentrations. Kool Kount provides data within hours to allow for more precise control of active biomass concentrations in the waters.1.1 This test method covers the determination of viable active biomass in cooling tower water in the range from 102 to 108 cfu/mL. It is a semiquantitative test method.1.2 This test method was used successfully with reagent water, physiologic saline, and cooling tower waters. It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.