Investigation of turbidity removal and energy consumption from pistachio processing industry wastewater by electro-oxidation process

Abstract

ABSTRACT. In this study, it was aimed to remove turbidity, which is an important parameter of water quality, and to examine energy consumption from pistachio processing industry wastewater (PPIW). As working parameters, mixing speed, supporting electrolyte (SE) type and concentration, initial pH value of wastewater, and current density were examined. Graphite was used as the anode material, and stainless steel was used as the cathode material. The highest removal for the mixing speed parameter was achieved at 400 rpm, the maximum efficiency for the SE type was achieved at NaCl, a concentration of 2 M for the SE concentration, a pH of 3.0 for the wastewater initial pH value, and a current density of 30 mA/cm2. However, considering the energy consumption cost in these parameters, the optimal conditions were determined as 1.25 M of SE, pH 3.0, mixing speed of 400 rpm, and current density of 6 mA/cm2. In these conditions, the turbidity removal efficiency was found to be 90.61%. Energy consumption for the same conditions is calculated at 180 kWh/m3. In the results obtained, it is observed that energy consumption decreases as the concentration of SE increases. NaCl, which is the electrolyte that provides maximum efficiency in removing turbidity, is also the electrolyte that provides minimum energy consumption. In electrochemical systems, the cost is as important as lifting efficiency. Therefore, the choice should be made, considering which of these two parameters will be the priority.                 KEY WORDS: Electro-oxidation, Turbidity removal, Graphite anode, Wastewater treatment   Bull. Chem. Soc. Ethiop. 2022, 36(1), 223-234.                                                          DOI: https://dx.doi.org/10.4314/bcse.v36i1.18