Physicochemical and microbiological characterization of effluents from Mohammed VI University hospital in Marrakech and their environmental impact assessment

Contamination of sewage water has become a critical public and scientific issue due to its adverse effects on human health and biological ecosystems, hence presenting grave health risks to workers, the general population, and the environment. The purpose of this study is to investigate the physicochemical and biological indicators of hospital wastewater from the Mohammed VI University Hospital in Marrakech, which is poured into the municipal sewage system without treatment. Sampling of hospital wastewater was conducted from October 2022 to January 2023, every 15 days, from the main collector of all the manholes of the hospital. The high level of organic pollution was confirmed by physicochemical characterization, with average COD, BOD₅, and TSS values of 750 mg/L, 512.14 mg/L, and 879.86 mg/L, respectively, which exceeded the Moroccan recommended discharge standards. In addition, total phosphorus content, sulfates, nitrates, and nitrites content were found to be 5.92 mg/L, 427.97 mg/L, 7.39 mg/L, and 0.60 mg/L, respectively. Fecal coliform bacteria content up to 12 x 10⁶ CFU/100 mL was recorded in the bacteriological characterization, as well as the presence of nosocomial pathogens, namely Staphylococcus aureus. The ratio COD/BOD₅ of 1.46 also suggests moderate biodegradability of hospital wastewater. Based on findings, appropriate treatment strategies are suggested, such as activated sludge processes, sequencing batch reactors (SBR), membrane bioreactors (MBR), anaerobic digestion, and advanced oxidation processes (AOPs). In view of the physicochemical and pathogenic bacterial load of these effluents, their proper treatment is obligatory as a precautionary step to prevent any threat to public health and outbreak of epidemic diseases.