Treated Wastewater Reuse: An Efficient and Sustainable Solution for Water Resource Scarcity

Wastewater has become a valuable resource in many regions of the world that face increased level of freshwater scarcity. Reuse of treated wastewater has high economic benefit, but it can also lead to environmental pollution. As such, explicit conditions must be defined to determine the optimality of wastewater reuse for society. In this paper, we develop a regional multi-sectoral model of water quantity–quality interaction among the urban, agricultural, and environmental sectors. Our interest lies in the feasibility of reuse, rather than the stability of the regional arrangements, therefore we apply a social planner’s approach to this regional problem. We formally construct sufficient conditions that support the superiority of infrastructure development and conveyance of treated wastewater for irrigation, when measured against other common disposal alternatives. Using a numerical illustrative example, which relies on data and results from existing literature, we were able to replicate our theoretical findings, as well as to examine their robustness, when supporting assumptions are relaxed.