Integrated Asset Management Planning of Wastewater Collection and Treatment Systems

In most Canadian municipalities, wastewater collection (WWC) and wastewater treatment plants (WWTPs) are owned and managed by separate municipal governments. Linear sewer pipe networks are owned and managed by utilities at the lower tier of municipal government, and vertical treatment plant assets are owned and managed by regional governments at the higher level. Under this arrangement, regions charge utilities for treating their collected wastewater. The linkage between the WWC and WWTP systems are presented and modeled by taking the system dynamic approach. Three asset management scenarios are developed and evaluated for a joint WWC and WWTP system. Based on the simulation results, the main goal of financial selfsustainability is achieved when the maximum annual rehabilitation rate is 0.88% of the total WWC network length. However, adapting the higher rehabilitation rate of 1.1% is more desirable because of avoiding the downstream capital costs for building new WWTP capacities. This study demonstrates that the applying such integrated models will help decision makers to evaluate the behavior of interrelated wastewater collection and treatment systems, and find synergistic cost-saving opportunities while taking decisions on when, where, and how to invest in infrastructure upgrading and rehabilitation.