Biofilm formation comparison of the SANIPACKING® cooling tower fill material against standard polypropylene fill material in a recirculating model water system

Cooling towers are heat rejection systems that are used in some industrial applications, and they have the potential to develop infectious concentrations of Legionella pneumophila. SANIPACKING® cooling tower fill material and standard polypropylene fill material were compared in terms of biofilm formation potential and anti-Legionella activity within a 4-month period using a laboratory-scale recirculating water system. The recirculating water system was experimentally infected with a L. pneumophila standard strain (ATCC 33152) suspension and operated continuously until all experiments had been completed. Results showed that the L. pneumophila rapidly multiplied in a short time during the study within the model system bulk water. No L. pneumophila was isolated from the SANIPACKING® surface during the 4-month period, whereas intensive colonization occurred on the standard polypropylene material surface in the first month. Heterotrophic bacterial counts on the surfaces showed that a significantly low accumulation was recorded on the SANIPACKING® surface in comparison to the standard polypropylene material. Total bacterial counts on surfaces, determined by epifluorescence microscopy (using DAPI), revealed that significantly low counts of microorganisms colonized on the SANIPACKING® surface.