Water Quality Modelling in Water Distribution Systems: Pilot-Scale Measurements and Simulation

We present the results of water quality measurements in a pilot-scale, continuously circulated test rig consisting of HDPE pipe segments, where pH, conductivity, turbidity, salinity, temperature, and dissolved oxygen were measured daily. Microbiological measurements (CFU) on the pipe wall and in the bulk water were measured at least once every week. The measurement campaign lasted for 18 weeks. In the first part of the paper, we provide an overview of the results and our experiences. In particular, the time histories of the measured quantities are presented and assessed. Additionally, the flow velocity was increased in six steps from 0.4 to 1.1 m/s to study biofilm detachment once every week. In the second part of the paper, we attempt to use these measurement results for the parameter identification of standard biofilm models. In particular, we search for indirect connections between our measurement results and model parameters (e.g., yield and growth-limiting parameters) via optimising, where the objective is to recover the measured CFU concentration results as closely as possible. Finally, we present preliminary results on the critical wall shear stress resulting in biofilm detachment.