Decentralized water reuse: regional water supply system resilience benefits

Resilience is related to the system functionality loss and the failure event duration (Bruneau et al. 2003). System redundancy and robustness affect the severity or functionality loss while the recovery time is largely related to the resource available and rapidity of the response. The purpose of this study is to investigate the resilience of a regional water supply system (RWSS) through a criticality analysis of five RWSS components. The relative importance was evaluated under two management/ design conditions: (1) centralized versus decentralized wastewater treatment, and (2) decentralized wastewater plant location. For this study, the regional water supply system of a portion of the Tucson metropolitan area in Arizona was modeled. A Linear Programming (LP) flow allocation model determines the optimal flow allocation from multiple sources to users by minimizing the operational cost. The RWSS resilience was quantified by the failure, that is, the volume of water that was not delivered to users during the component failure of known duration.