Techno-economic evaluation of electrocoagulation for cattle slaughterhouse wastewater treatment using aluminum electrodes in batch and continuous experiment

Abstract

This study aimed to investigate, from a techno-economic point of view, cattle slaughterhouse wastewater (CSWW) treatment via the electrocoagulation (EC) technique. A novel lab-scale EC unit with a 3 L volume was manufactured and tested. The EC unit contains nine identical cylindrical shape electrodes from aluminum material in connection with a controllable DC power supply. Investigation of optimum operating parameters in terms of pH, current density (CD), contact time, and electrolyte concentration was carried out in batch mode and then applied to continuous mode. At each batch, a cost analysis was calculated in terms of the consumption of electrode material and electrical power. The optimum operating conditions at which the best removal efficiency was achieved were pH 7, contact time 75 min, total dissolved solids of 3000 mg L−1, and CD of 4 mA cm−2. After application of these conditions on continuous flow mode, the removal efficiency of chemical oxygen demand, color, turbidity, biological oxygen demand, and oil, grease were 95, 99, 99, 97 and 95%, respectively. The total electrode consumption and electrical consumptions were 0.6 kg m−3 and 0.87 kWh m−3 with an operational cost of about $1.5 m−3. This proved that EC is a techno-economically effective treatment method than other conventional treatment methods for high-rate removal of pollutants from CSWW.