Since the late 1970s, there have been many small and large outbreaks of Legionnaires’ disease. Most of these outbreaks have been traced to either cooling tower water systems or potable water systems. Although the bacteria most often associated with Legionnair’s disease, Legionella pneumophila, is present in many waater systems, outbreaks are usually a result of large concentrations of Legionella pneumpohila.
This paper is a report of the work conducted in association with the Centers for Disease Control at their facility in Atlanta, GA. A model cooling tower was constructed that recirculated water and rejected heat through evaporation. This model system was inoculated with know concentrations of bacteria and amoebae. It was allowed to reach equilibrium and then biocides, such as ozone chlorine, chlorine dioxide, and monochloramine, were applied to determine their efficacy in controlling the total bacteria and the legionella in particular.
The results of this study are summarized in this paper.
Cooling tower legionella pneumophila study CDC