Performance evaluation of a brewery wastewater treatment plant: A case of Heineken Brewery, Addis Ababa, Ethiopia.

Untreated wastewater from the brewing industry poses significant environmental risks due to its high organic content. Therefore, this study evaluates the wastewater treatment system at Heineken Brewery in Addis Ababa, Ethiopia. Key parameters analyzed include COD, BOD₅, TSS, pH, ammonia (NH₃), total nitrogen (TN), total phosphorus (TP), electrical conductivity (EC), temperature, turbidity, and volatile fatty acids (VFA). These parameters were analyzed following the procedures of the American Public Health Association's standard. The treatment system demonstrated notable efficiency, with influent temperature decreasing from 29.37 °C to 25.35 °C, remaining well below the acceptable limit of 40 °C. The pH dropped from a mean of 9.3 to 7.5, aligning with the acceptable range of 6-9. COD and BOD₅ were significantly reduced by 97.2 %, achieving levels well below discharge limits of 250 mg/L and 60 mg/L, respectively. TSS levels decreased by 95.7 %, with a mean of 32.3 mg/L. However, TP and TN removal efficiencies were lower at 49.4 % and 57.6 %, respectively, with TP slightly exceeding the limit of 5 mg/L. The system effectively reduced VFA by 94.3 % and turbidity by 71.5 %. While parameters such as pH, temperature, TN, NH₄-N, and EC were within acceptable limits, the high nutrient concentrations in the final effluent indicate potential environmental contamination if discharged untreated. Overall, while the treatment plant shows commendable pollutant removal efficiency, further optimization is needed for improved nutrient management.