Optimization of Coagulation-Flocculation Mechanism to Reduce Chemical Oxygen Demand in Domestic Wastewater

The efficient treatment of Domestic Wastewater (DWW) through the coagulation and flocculation mechanism is essential to reduce the Chemical Oxygen Demand (COD), which not only contributes to the improvement of the environment but also to the possible reuse in agricultural irrigation. The objective of this research was to optimize the coagulation and flocculation process to reduce the COD in the DWW of a tributary of the Mantaro River in the district of El Tambo-Huancayo. The developed methodology included the collection of DWW through representative sampling, the initial and final measurement of the COD and pH, the preparation of the coagulating agent and the adjustment of the intensity of agitation using the jar test equipment, using a 4×2 factorial design. Four PAC concentrations (40, 60, 80 and 100 ppm) and two agitation speeds (100 and 200 rpm) were tested using jar tests under controlled conditions. The results showed statistically significant differences between treatments (p < 0.001). The combination of 60 ppm PAC and 100 rpm achieved the highest efficiency, with a 69.33 % COD removal. At higher doses, a decrease in performance was observed, attributed to the phenomenon of overdosing. The coagulation process proved to be effective in decreasing COD in DWW, and optimization of treatment parameters can further improve its efficacy