On the economic analysis of wastewater treatment and reuse for designing strategies for water sustainability: Lessons from the Mexico Valley Basin

Abstract

As the global economy continues to grow and water challenges become more complex and urgent, there is an increasing need for assessing the contributing role of wastewater treatment and reuse to designing strategies for water sustainability. For economic analysis, this need calls for modeling frameworks capable of representing the particularities of the relationship between economic systems and water resources in terms of appropriation from natural sources, utilization by production processes, and generation, treatment, reuse, and discharge of wastewater. We explore an integration of these particularities into an input-output model of the economy designed for technological choice featuring resource endowments as production constraints. We apply the model for studying the intentional reuse of treated wastewater in the regional economy of the Mexico Valley Basin, whose highly intervened hydrology is compromised by unsustainable exploitation of natural sources and minimal treatment of wastewater flows. We design scenarios for testing the response of the economic system to the constraining of groundwater extraction by aquifer recharge and to the reduction of leaks in domestic networks. Our findings indicate that avoiding aquifer overexploitation requires treatment processes to generate up to 1.4 km3yr−1 of high quality water for intentional reuse, while the control of domestic leaks can reduce regional water intake by 13% and, therefore, reduce the required treatment effort to 0.9 km3yr−1. The extent to which these results can support the design of a strategy for water sustainability with empirical relevance for this region ultimately depends on accurate representations of treatment technologies and conveyance infrastructure in economic models. We suggest that detailed representations of technologies for water distribution and wastewater treatment into economy-wide analysis constitute an important field of collaboration for industrial ecologists and input-output economists for the near future.