Biofilm formation in a large sized experimental set up of a drinking water distribution system consisting on various pipe materials

Abstract: Abstract In water distribution systems newly exposed areas, such as newly laid pipes are subjugated to biofilm growth. This growth have been associated with public health problems and has lead to the water treatment facilities seen today. In an attempt to better understand what mechanisms are important when it comes to drinking water, research involving simulated distribution systems is being used. These systems imitate real systems but are small and cannot fully recreate all the changing parameters normally seen. In this study, tubes out of the materials Polyethene (Pe), Polyvinyl chloride (PVC) and treated Pe (tPe) lined with Prebona protect was constructed into a large sized drinking water distribution system, to answer which material promoted the highest amount of biofilm. The developmental curves of the biofilm on different materials were compared in this large sized experiment with smaller sized versions done in other studies. Significance and differences were seen in a heterotrophic plate count (HPC) between three and seven day count in tPe tubes which indicated biofilm formation. When comparing materials with each other there were no differences seen regarding bacterial growth. In comparison to other studies (Manuel, Nunes, and Melo 2007, Tsetanova, 2006), which used pilot rig system, showed similar growth as in the present paper with a large sized system. The developmental curves appeared indistinguishable in this experiment, but to clarify this more rigs should be used and studied in an earlier stage. Also, characterization of biofilm by DNA sequencing would further highlight the differences between materials used. However, the comparison between large sized tubes in the distribution system and a pilot rig used by others suggests that the use of pilot rig systems are adequate.