Impact of operating parameters of electrocoagulation-flotation on the removal of turbidity from synthetic wastewater using aluminium electrodes

Abstract

This study analyzed the dominant operating parameters of electrocoagulation-flotation (ECF) that would influence the removal efficiency of turbidity from synthetic wastewater using aluminium electrodes with an inter-electrode distance of 5 mm. These parameters included current density (CD), initial pH, electrolytic conductivity, coagulant dosage, operating time, initial turbidity concentration, and stirring speed. The initial turbidity concentration and electrolytic conductivity were synthesized based on typical concentrations of various resources such as drinking water, wastewater, seawater, and oil field-produced water. A novel approach has also been proposed for the evaluation of EC performance and selection of an appropriate process for the removal of sludge based on the intake’s initial concentration. The experimental results revealed that the optimal conditions for removal of turbidity (90 %) were attained at CD = 0.0028 A/cm2, initial pH = 7.3, operating time = 5 min, and stirring speed = 500 rpm. The settling times of 5 and 15 min were also evaluated, in order to optimize the design of the settling tank. The results also revealed that ECF formed the flocs larger than 20 µm, so that after filtration with a filter paper of 20 µm, a removal efficiency of 98 % was attained.