Treatment of olive processing wastewater by electrocoagulation: An effectiveness and economic assessment.

In the present study, the technique of electrocoagulation (EC) followed by filtration was explored at the laboratory scale for the removal of organic compounds from olive debittering wastewater (ODW). Different parameters such as electrode type and distance as well as sample pH, current density, and electrolysis time were investigated in batch experiments with identical electrode geometries. Our results showed that highest pollutant removal efficiency and lowest operational cost were achieved using two Al electrodes at a distance of 1 cm apart with a sample pH of 4.0. Moreover, rises in the electrolysis time and current density (up to 60 min and 15 mA cm-2, respectively) led to improvements in the removal of chemical oxygen demand (COD), total polyphenolic compounds (TPC), and turbidity. Under optimized conditions, the removal of COD, TPC and turbidity reached 78.51, 90.44 and 97.92%, respectively; the values of 1.01 g m-3, 12.0 kWh cm-3 and 0.12 USD m-3 were calculated as the electrode consumption, electrical energy consumption and operating cost, respectively. Chromatography results revealed tyrosol and catechin as the main phenolic compounds present in both the initial effluent and the generated sludge.