Water Distribution Losses Caused by Encrustation and Biofouling: Theoretical Study Applied to Walkerton, ON

Abstract

Encrustation and biofouling causes loss in carrying capacity of water mains and impacts water quality. In this work, the decrease in pipe diameter and increased pipe roughness are computed as a function of service age of water mains. The method is applied to the water distribution network in Walkerton, Ontario and the effects of encrustation and biofilm build-up with age and their effects on the hydraulics are estimated. Hydraulic analysis was performed by simulating the flow through the water supply network, assumed to be 100 years old, using EPANET2. The results indicate that changes in the hydraulic parameters of a network can cause 1. a change in a flow pattern from reservoirs, 2. water to take a longer time to reach the far end of network and 3. increased energy cost. It is also suggested that the available empirical model to compute pipe roughness and decrease in pipe diameter after a certain service time cannot be standardized, because of its dependence on the local and transient quality of water from various supply sources.