Comparison of electrocoagulation and photocatalytic process for treatment of industrial dyeing wastewater: Energy consumption analysis

摘要

Several processes have been used for dye and chemical oxygen demand (COD) removal from wastewater. Comparision of these methods are important in terms of efficiency and energy consumption. In recent years, advanced oxidation processes (AOPs) and electrocoagulation (EC) are the best methods for industrial dyeing wastewater treatment. In this study, comparision of energy consumption related to EC and photocatalytic process has been investigated. Effect of operational parameters on efficieny of both methods were studied. Effective parameters in EC treatment were initial pH, current density and distance between electrodes. In the photocatalytic process initial pH, photocatalyst concentration and aeration are effective parameters. Decolorization, COD removal, and energy consumption are as responses. Under the optimum conditions, decolorization and COD removal for EC and photocatalytic process were 85.57 and 34.48%, and 81.39 and 67%, respectively. Considering the same time for both methods, decolorization was the same, but COD removal was higher in photocatalytic processs. Energy consumption of EC process (<0.01 kWh/m~3.order of pollutant removal) was very lower than photocatalytic process (>100 kWh/m~3.order of pollutant removal). Since the wastewater treatment process must be economic, EC process was chosen. Another method such as photocatalytic processs must be selected due to improve the output.