Integrating Sustainability Criteria in Wastewater Treatment Selection: A MACBETH ‐Based Multi‐Criteria Decision Framework for the City of Settat (Morocco)

This study applied the Measuring Attractiveness by a Categorical Based Evaluation Technique (MACBETH) multi‐criteria method to identify the most suitable technology for reusing treated domestic wastewater in Settat, Morocco. MACBETH was selected over competing multi‐criteria methods for its ability to derive cardinal attractiveness scores directly from qualitative pairwise judgments, while embedding an automatic consistency check on expert preferences. Five alternatives: activated sludge, aerated lagooning, reed bed filters, natural lagooning, and bacterial beds were evaluated against 18 environmental, economic, and social criteria, elicited from a panel of 44 stakeholders (doctoral researchers, academics, domain experts, and engineers) and cross‐checked against the literature. Each score was further traced to its primary evidentiary basis to ensure methodological transparency and reproducibility. Environmental criteria, particularly treatment efficiency and energy consumption, dominated the weighting structure (44.93%), followed by economic (37.17%) and social (17.90%) dimensions. Reed bed filters achieved the highest overall attractiveness score, combining satisfactory purification performance, low energy demand, moderate cost, and strong social and environmental compatibility. A dedicated sensitivity analysis, replicating the MACBETH aggregation in Python across six weighting scenarios (±10%–20% environmental variation and equal family weighting), confirmed that reed bed filters retain the top rank throughout, even when the economic family becomes numerically dominant. These findings support nature‐based solutions as a robust choice for sustainable wastewater reuse in water‐scarce, semi‐arid regions, while highlighting boundary conditions (land availability, effluent‐quality requirements, and hydraulic loading) that bound the generalizability of the recommendation.