Optimal design of water reuse networks in cities through decision support tool development and testing

Abstract

Water scarcity and droughts are an increasing issue in many parts of the world. In the context of urban water systems, the transition to circularity may imply wastewater treatment and reuse. Planning and assessment of water reuse projects require decision-makers evaluating the cost and benefits of alternative scenarios. Manual or semi-automatic approaches are still common practice for planning both drinking and reclaimed water distribution networks. This work illustrates a decision support tool that, based on open data sources and graph theory coupled to greedy optimization algorithms, is able to automatically compute the optimal reclaimed water network for a given scenario. The tool provides not only the maximum amount of served reclaimed water per unit of invested cost, but also the length and diameters of the pipes required, the location and size of storage tanks, the population served, and the construction costs, i.e., everything under the same architecture. The usefulness of the tool is illustrated in two different but complementary cities in terms of size, density, and topography. The construction cost of the optimal water reclaimed network for a city of approximately 100,000 inhabitants is estimated to be in the range of €0.17–0.22/m3 (for a payback period of 30 years)

G. B., E. C., J. C., and D. M. acknowledge the research funded by the Spanish State Research Agency of the Spanish Ministry of Science and Innovation with the project code: PID2020-115456RB-I00/MCIN/AEI/10.13039/501100011033; ReUseMP3. J. P.-R. acknowledges the H2020 EU project MULTISOURCE (GA101003527). We thank Generalitat de Catalunya through Consolidated Research Groups 2021-SGR-01125 and 2021-SGR-01283. ICRA researchers thank the CERCA program/Generalitat de Catalunya for their funding. Miquel Farreras thanks the Generalitat de Catalunya and European Social Fund for his FI fellowship (2020 FISDU00590). D. M. thanks the Universitat de Girona for his FI fellowship (IFUdG 46 2022). G. B. acknowledges Spanish State Research Agency of the Spanish Ministry of Science, Innovation and Universities for the Grant to the Creation of a permanent position Ramon y Cajal 2014 (RYC-2014-16754)

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