Distributed wastewater treatment and reuse as a water supply: impact on urban water system resilience

Abstract

Water and wastewater systems are critical infrastructure whose disruption directly threatens public health, economic growth, as well as the reliability and functionality of other critical infrastructure including power, transportation, and health care systems. Hybrid urban water supply systems that combine conventional, centralized water sources with distributed sources such as reclaimed wastewater have great potential to reduce energy consumption while minimizing freshwater withdrawal. In this study, we quantitatively analyze the impact of distributed direct potable reuse of municipal wastewater on the resiliency of urban water supply systems using the City of Houston’s municipal water system as a testbed. A hybrid system configuration that supplements centralized drinking water supplies with reclaimed wastewater from distributed treatment and reuse systems exhibits lower severity, range of impact, and duration of substandard performance compared to the centralized design. Benefits are most prominent in areas more susceptible to a variety of systemic or localized disruptions in the centralized system. The analyses reveal vulnerable components in the current system and identify appropriate mitigation strategies that account for local geographical constraints. Findings from this study provide quantitative evidence for the risks current urban water systems face, underscoring the necessity to consider alternative system configurations for better performance and higher resilience.