Operational Stability and Treatment Efficiency of a Reverse Osmosis Plant Treating Highly Mineralized Water: Results of a Four-Year Follow-Up Study.

This study evaluates the long-term operational performance of a full-scale reverse osmosis desalination plant treating highly mineralized water under real industrial operating conditions. Unlike conventional laboratory or pilot-scale investigations, the analysis is based on four years of operational data (2020-2024), providing a representative assessment of membrane system behavior under variable environmental and hydraulic conditions. Statistical analyses including descriptive statistics, time-series analysis, Pearson correlation, and inter-annual comparisons were performed using Python-based data-processing tools. An Operational Stability Index was also introduced to quantify process consistency over time. The results demonstrate stable desalination performance, with salt rejection exceeding 90%. Operational monitoring indicated effective pretreatment conditions, low SDI values, and controlled membrane fouling under long-term operation. Differential pressure evolution and cleaning-in-place performance further confirmed the effectiveness of the implemented fouling mitigation strategy. Membrane autopsy investigations revealed the coexistence of biological fouling, silica scaling, and localized oxidative degradation, highlighting the importance of integrated pretreatment and operational control. The findings demonstrate the value of long-term industrial monitoring for understanding membrane performance, fouling behavior, and operational stability in full-scale RO systems. This approach supports data-driven operational optimization and may contribute to the future development of predictive monitoring and intelligent desalination-management frameworks as a Digital Twin.