Biofilms on polymeric pipes
Past research has focused on the effect that different polymeric pipe materials have on biofilm formation in drinking water distribution systems (DWDS), to determine the best one to deliver safe drinking water to customers. However, results are often contradictory. Here, we studied the influence of five polymeric pipe materials on biofilm development in unchlorinated drinking water in simulated DWDS conditions. Coupons made from two high-density polyethylene (HDPE-1 and HDPE-2), two unplasticized polyvinyl chloride (PVC-1 and PVC-2), and a molecularly oriented polyvinyl chloride (PVC-O) were tested for biofilms formation. Biofilms were grown from real drinking water on the selected materials in a flow-chamber set-up simulating DWDS conditions. Microbial community analysis of biofilms by means of 16rRNA gene sequencing showed a common core microbiome on all the materials tested in nutrient-rich and oligotrophic conditions, with a high variability even within duplicates of the same material. Presented findings in combination with multiple studies available in the literature suggest that no conclusion can be made of whether PVC or PE is ultimately better in preventing biofilm formation in DWDS.