Experimental measurements of biofilm thickness in drinking water pipes

Biofilms in drinking water distribution systems (DWDS) challenge water quality, infrastructure and public health. Current monitoring methods often disrupt biofilms or lack spatial coverage. This study explores two novel, non-intrusive techniques to measure biofilm thickness: one based on heat resistance, the other on changes in hydraulic residence time. Experiments were conducted in a lab-scale DWDS simulator replicating realistic pipe conditions. Both methods were evaluated against traditional destructive sampling to assess accuracy. Results show that the residence time method yields consistent, reliable estimates closely matching physical samples, while the heat resistance approach shows greater variability and requires refinement. Sensitivity analyses further demonstrate that the residence time method is more robust under varying operational conditions. These findings highlight its potential for field deployment, offering a scalable and minimally invasive solution for real-time biofilm monitoring. This advancement could support improved water quality management through targeted interventions in actual DWDS environments.