Bacterial biofilm formation on polyvinyl chloride, polyethylene and stainless steel exposed to ozonated water

The formation of biofilm on polyvinyl chloride (PVC), polyethylene (PE) and stainless steel surfaces was studied in bank infiltrated and chemically purified waters without (control water) and with ozonation. Ozonation increased the concentration of assimilable organic carbon (AOC) in water (78 vs 450 μgC/l). Ozonation of water increased the viable numbers and cell volume of heterotrophic bacteria on the surfaces. The highest bacterial count, 7.7×105 cfu/cm2, was detected on PVC surface after three weeks’ exposure to ozonated water. The numbers of heterotrophic bacteria on surfaces reflected the bacterial numbers in water. There was no difference in total cell count on different surfaces and in control and ozonated waters. Direct staining of microbes on the surfaces produced higher cell count per cm2 than enumerating microbes detached from surfaces by sonication. In general, the accumulation of biofilm on different surface materials was quite similar. Only the cell volume was slightly higher on PE than on PVC surface.