Participatory Adaptive Planning for Sustainable Industrial Treated Wastewater Reuse in the Mediterranean: Evidence from Case Studies in Türkiye and Tunisia

The Mediterranean region faces severe water scarcity exacerbated by climate change. The reuse of treated industrial wastewater for industrial processes or agricultural irrigation offers a sustainable mitigation strategy, yet its implementation is hindered by low social acceptance and institutional fragmentation. This study aims to enhance treated wastewater reuse (TWWR) uptake within the textile and pharmaceutical sectors in Türkiye and Tunisia through structured stakeholder engagement, hydrological modelling, simulation, and co-design of preferred strategies. Data were collected from regional water authorities, industries, farmers, and civil society, chosen based on their influence, interest, and capacity regarding integrated water management. A Participatory Adaptive Planning framework was applied across three co-designed workshops per site, and interviews. Data were charted using the Natural Assurance Schemes Business Canvas and a conceptual visual support framework. Stakeholders identified key barriers, including legislative gaps in Türkiye and financial capabilities and farmer reluctance in Tunisia. Through the conceptual visual support framework, holistic strategies combining TWWR, water savings, urban treated wastewater quality improvement by tertiary treatment, desalination, and Managed Aquifer Recharge were co-created, simulated and ranked. Technological innovation in wastewater treatment is insufficient without robust “social readiness”. Participatory governance effectively aligns environmental engineering solutions with societal needs, establishing a foundation for resilient and integrated water management action plans.