Feasibility of Treated Wastewater Reuse Regarding Multiple Demands: A Pilot Study in Portugal

Despite the potential of wastewater reuse, Portugal's current usage stands only at 1.2%, significantly lower than the national targets. This research addresses this gap by carrying out a detailed assessment of the Tagus River and Ribeiras do Oeste Basin. The objective was to identify and characterize potential pilot cases for wastewater reuse, especially in the agriculture and tourism sectors, aiming to inform future national strategies and potentially serve as a framework for similar evaluations in other regions. The methodology analysed wastewater treatment plants (WWTPs) managed by Águas do Tejo Atlântico S.A., evaluating multiple treatment systems and distribution networks and performing cost analysis and risk assessments. Eight WWTPs were selected based on their potential for reusable wastewater production and proximity to users. Findings reveal that reusing water from these WWTPs could significantly increase regional and national reuse rates, benefitting over 2000 ha of agricultural land and golf courses. The study also presents a comparative cost analysis, showing that the costs of reclaimed water in Portugal are competitive with other European regions. The research highlights the importance of strategic WWTP location, considering the high costs associated with distribution networks and energy consumption, suggesting a paradigm shift towards relocating WWTPs to optimize reuse costs and energy consumption, contributing to a more circular society. This study lays a foundation for policy-making and strategic planning in the region, promoting sustainable water management in the face of climate change challenges.