Rating sustainability aspects of reverse osmosis desalination plants using multi-criteria decision-making approach

Desalination has become a vital global water source with significant economic, environmental, and social impacts. Governance institutions are increasingly applying sustainability principles to desalination. Given the scarcity of high-quality freshwater and growing populations, desalination ensures water security in Egypt. Despite environmental impacts and high energy consumption, desalination projects are not fully integrated into green rating frameworks. However, despite their importance, limited research efforts have been made to score and rank desalination plants using Multi-Criteria Decision-Making (MCDM) techniques. This research addresses this gap by proposing a sustainable assessment framework integrating sustainability, MCDM techniques and sensitivity analysis. Benchmarking regional and international rating systems to highlight sustainable categories and criteria. The developed system includes 26 criteria in seven categories: 1) General Requirements, 2) Sustainable Site, 3) Energy, 4) Water Efficiency, 5) Materials and Resources, 6) Emissions and Environment, and 7) Culture and Economy. The rating system classifies desalination plants into six levels: Unsustainable, Certified, Bronze, Silver, Gold, and Platinum. A key novelty of the study is the dual application of two developed MCDM techniques, Best-Worst Method (BWM) and Full-Consistency Method (FUCOM), which are rarely used in infrastructure assessments, particularly in the desalination sector. They are used to determine categories and criteria weights. To measure the consistency between BWM and FUCOM results, a Weight Similarity Coefficient (WSC) was calculated. The overall WSC value was 0.83, indicating high consistency between the two methods. The most important and the least important categories and criteria were determined by conducting questionnaire surveys completed by desalination plants experts. The framework is applied to East Port-Said Reverse Osmosis (RO) Water Desalination Plant as a case study. The Plant received a high sustainability ranking (“Silver”) with a score of 73.24 and 72.58 using BWM and FUCOM, respectively. Sensitivity analysis assesses the effectiveness of categories and criteria using deterministic and Monte Carlo regression-based analysis. Results reveal that BWM and FUCOM rankings are sensitive to category weight variations, emphasizing the importance of precise weighting in sustainability assessments.