Zooming in on Network Fouling Locations

PWN strives for as few water quality complaints as possible. There is a strong interest in understanding the fouling mechanisms and finding a more long-term solution to reduce the brown water complaints. Therefore PWN records the turbidity of all their flushing actions. In this paper 30 turbidity datasets of low-flow flushing actions over a period of 18 months were analyzed in two ways. First, the sediment accumulation rate of the total network was analyzed and second, the locally accumulated material per pipe was studied. The hypothesis is that the location and amount of sediment accumulation may be related to temperature, the location of branches and appurtenances, and the maximum flow velocity. The results show that temperature is an important factor for sediment build-up in the study area; accumulation rate increased with higher water temperature. The location of branches in mains may or may not play a role. It seems that more sediment is accumulated around the branches (both before and after the branches). The influence could not be quantified as the branches are relatively close to each other. The influence of maximum flow velocity could not be determined in this relatively small study area.