Firomsa Bidira - Faculty of Civil and Environmental Engineering, Jimma Institute of Technology, Jimma University P.O. Box ۳۷۸, Ethiopia
Zerihun Asmelash - Faculty of Civil and Environmental Engineering, Jimma Institute of Technology, Jimma University P.O. Box ۳۷۸, Ethiopia
Seifu Kebede - Faculty of Civil and Environmental Engineering, Jimma Institute of Technology, Jimma University P.O. Box ۳۷۸, Ethiopia
Abrham Bekele - Corresponding author: School of Chemical Engineering, Jimma Institute of Technology, Jimma University P.O. Box ۳۷۸, Ethiopia

Background: Coffee is the foundation of Ethiopia’s economy, but the wastewater generated by coffee processing cannot be properly treated, therefore, causing various environmental problems. Methods: In this research, electrochemical oxidation(ECO) and photo electrochemical oxidation(PECO) are combined with UV and hydrogen peroxide (UV/H۲O۲) to reduce organic compounds in coffee processing effluent with color and turbidity effect. The effects of various experimental parameters such as hydrogen solubility (pH), sodium chloride and calcium chloride (NaCl and CaCl۲) concentrations, current and electrolysis time, and H۲O۲ dose were investigated. Results: The results were investigated and analyzed using response surface methodology (RSM) and Microsoft Excel. The color (۹۹.۶%) and turbidity (۹۹.۴%) were removed by combining ECO with UV/H۲O۲, which produces high amounts of hydroxyl ions (OH-), oxidizes large amounts of contaminants, and increases efficiency. These results were obtained at pH ۷, current of ۰.۴۰ AMP, and ۱.۵ g CaCl۲ after ۴۰ minutes of electrolysis. The operating factors were pH, electrolyte dosage, time, current and H۲O۲, which plays a major role in increasing the removal capacity of photoelectrochemical oxidation for coffee processing waste water treatment. CaCl۲ was once more wonderful in the removal of organic compounds from coffee processing effluents. Conclusion: Therefore, the introduction of this ultraviolet light is a powerful oxidant with H۲O۲, which can improve pollution control. An analysis of variance (ANOVA) with a ۹۵% confidence interval can be used to determine the magnitude of the independent variable.

Coffee, Wastewater, Water purification, Ethiopia