Optimization of an electrocoagulation-assisted adsorption treatment system for dairy wastewater

Abstract

This study aimed to investigate the effectiveness of combining electrocoagulation with adsorption on natural zeolite (ECA) for the treatment of industrial dairy wastewater. The response surface methodology (RSM) was employed to analyze the process. Several operating parameters were investigated, including the initial pH (5–9), electrolysis time (15–45 min), current density (12–48 A/m2), and the zeolite dosage (0.083–0.15 g/ml). The experimental design consisted of 30 runs, which were determined using the Central Composite Design (CCD). The key parameters measured were the removal efficiencies of chemical oxygen demand (COD), turbidity, and energy consumption. The obtained data were analyzed using Minitab 21.2 software, and regression models were constructed. The models demonstrated a strong coefficient of determination (R2), indicating a strong correlation between the experimental and predicted values. The optimal conditions for achieving 92 % COD removal and 97 % turbidity removal were found to be pH 7, a current density of 38 A/m2, an electrolysis time of 20 min, and a zeolite dosage of 0.183 g/ml. To evaluate the impact of natural zeolite on the treatment process, the results obtained from this experimental design were compared with those from a second design involving electrocoagulation (EC) alone (based on 20 runs). The comparison revealed that the addition of natural zeolite did not enhance the treatment efficiency in terms of COD and turbidity removal in dairy wastewater.

Keywords

• Electrocoagulation
• Adsorption
• Dairy wastewater
• Response surface methodology
• Central composite design
• COD and turbidity removal