Bacteriological analysis of Oued Oum Er-Rbia water: Evolution and impact on quality and osmosis membrane

The Oued Oum Er-Rbia is an essential resource for Morocco's water supply, but is subject to increasing pollution from domestic and agricultural discharges. This study assesses microbiological contamination and its impact on reverse osmosis membranes in the Khénifra (2023-2024) and Tadla (2021-2023) treatment plants, using quarterly bacteriological analyses.Water samples were analyzed according to ISO 9308-1 [1] standards, including tests for total coliforms, E. coli and fecal streptococci. Polynomial regression modeling and 3D visualization were carried out using Python (Pandas, Scikit-learn, Matplotlib) to study the interactions between conductivity, residual chlorine and microbial proliferation (CFU/ml at 22°C).The results show that high conductivities (>3000 us/cm) favor membrane clogging, while stable residual chlorine (0.1-0.15 mg/l) limits bacterial proliferation. However, levels of revivable bacteria (>50 CFU/ml) indicate significant biofouling.The study recommends pre-treatment in Khénifra to reduce conductivity, and stabilization of residual chlorine in Tadla. Continuous monitoring and treatment optimization are essential to guarantee water that meets international standards and prolong the life of membranes.