Optimization and evaluation of the process variable’s effect on color and turbidity removal from coffee processing wastewater: Using a photoelectrochemical oxidation process

Abstract

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/H2 O2 ) 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 CaCl2 ) concentrations, current and electrolysis time, and H2 O2 dose were investigated. Results: The results were investigated and analyzed using response surface methodology (RSM) and Microsoft Excel. The color (99.6%) and turbidity (99.4%) were removed by combining ECO with UV/ H2 O2 , which produces high amounts of hydroxyl ions (OH- ), oxidizes large amounts of contaminants, and increases efficiency. These results were obtained at pH 7, current of 0.40 AMP, and 1.5 g CaCl2 after 40 minutes of electrolysis. The operating factors were pH, electrolyte dosage, time, current and H2 O2 , which plays a major role in increasing the removal capacity of photoelectrochemical oxidation for coffee processing waste water treatment. CaCl2 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 H2 O2 , which can improve pollution control. An analysis of variance (ANOVA) with a 95% confidence interval can be used to determine the magnitude of the independent variable.