Quantitative microbiological analysis of biofilm communities from the surfaces of different cooling tower materials

Abstract

Biofilms are complex communities of microorganisms attached to surfaces or associated with interfaces. Since biofilm formation is influenced by the type of surface materials, in the current study it was aimed to compare copper, stainless steel, galvanized stainless steel, polyvinyl chloride, polyethylene, polypropylene, ceramic and glass surfaces for biofilm formation rate. In this study, both monthly collected water and biofilm samples were analyzed in terms of total coliforms, faecal coliforms, Pseudomonas, aerobic mesophilic heterotrophic bacteria (at 22 and 37°C) and amoebas. We found that plastic polymers, especially polyethylene and polypropylene, supported the lowest total aerobic mesophilic heterotrophic bacterial numbers. Although the protozoa (amoeba) could found on to all of the surfaces, Pseudomonas species could harbour none of them. It can be concluded that selection of the suitable pipe material could reduce waterborne disease and minimize the possibility of biofilm development associated with the operation of cooling tower systems.