Highlights
- Mature biofilms are considered beneficial to non-chlorinated Danish drinking water distribution systems, as they increase the microbiological stability of the water.
- During commissioning of new pipes, biofilms start developing on the new pipe wall, and are influenced by factors such as water quality, pipe material, flow velocity and presence of biofilm upstream.
- The early stages of biofilm formation, prior to maturity, may impact water quality negatively and this is poorly understood.
- This study measured microbiological water quality parameters upstream and downstream of a newly commissioned PE pipe.
- High heterotrophic plate counts but low microbiological diversity was observed approximately 10 days after pipe commissioning.
- Diversity increased to upstream levels by day 15 and HPC decreased to upstream levels after 15–20 days.
- This study highlights the importance of obtaining and maintaining a stable biofilm composed of natural bacteria originating from groundwater in pipes of non-chlorinated systems to improve water quality for consumers. Optimizing pipe commissioning procedures can benefit the utility and it’s consumers.
