Cost optimization of tannery wastewater treatment by electrocoagulation process with iron electrode under various DC voltage and electricity consumption

Abstract

Electrocoagulation (EC) is an electrochemical technique in wastewater treatment that generates coagulant species in situ by electro dissolution of the sacrificial electrode. This work aimed to optimize the operating cost of tannery wastewater treatment by EC with iron electrodes under various DC voltages and electricity consumption. The experiment was conducted in a 400 mL batch electrochemical reactor using three iron electrode plates under a mono polar configuration and parallel distances of 26 mm. Several variations of voltage (8; 12; and 16 volt) and electricity consumption (1.7; 2.6; 3.4; and 4.3 kWh/m3) were applied. The reactor performance was evaluated based on the sedimentation curve using Imhoff cone. Simultaneously, the operating cost was analysed based on the electrode mass consumption and electricity consumption under variation in iron electrode price and electricity rates. The result showed that the optimum operating condition was obtained at the electrical voltage of 12 VDC and the electricity consumption of 2.55 kWh/m3. This condition had a current density of 1.7 A/m2, the electrode consumption rate of 0.31 kg/m3, and the operating cost of 0.45 – 0.55 USD/m3.