Physicochemical and microbiological characterization of the effluent from the Santiago oxidation pond, Ica, Peru

This study aimed to evaluate the physicochemical and microbiological quality of the effluent from the Santiago oxidation pond, Ica-Peru.A quantitative, descriptive, and cross-sectional study was conducted.Grab samples were collected from two discharge points within the system, and physicochemical and microbiological parameters were analyzed using standardized methods, with results compared against current environmental regulations.The results showed pH values within the permissible range (≈7.6); however, elevated concentrations of BOD₅ (152-166 mg/L), COD (545-733 mg/L), total solids (1013-1900 mg/L), and total nitrogen (125-135 mg/L) were recorded, exceeding regulatory limits.Additionally, total phosphorus substantially surpassed allowable thresholds, while total coliforms reached levels on the order of 10⁷-10⁸ MPN/100 mL, indicating a high sanitary risk.Differences between sampling points were identified, suggesting internal variability within the system.These findings reveal limitations in system performance under real operating conditions, consistent with previous studies on extensive treatment systems.It is concluded that the evaluated effluent does not comply with environmental standards for reuse.This study provides a novel baseline and highlights the need for continuous monitoring and operational optimization.