Investigating the influences of the cathode configuration on the electrocoagulation performance: A comparative study

Abstract

The treatment of oily wastewater is a critical environmental concern, and electrocoagulation (EC) has emerged as an effective method for reducing chemical oxygen demand (COD) from this type of wastewater. This study investigates the effectiveness of continuous electrocoagulation in removing COD from real oily wastewater using a cathode configuration electrode between two tubular anodes coupled in a monopolar-parallel fashion to a DC power source. The research compares the removal efficiency, current efficiency, and operating cost of One-Sided Finned cathode (1SF) made from aluminum and Two-Sided Finned cathode 2SF made from stainless steel. The operating parameters considered are electrolysis time, current density, and flow rate. The results indicate that the elimination effectiveness of chemical oxygen demand (COD) employing 2SF was higher than that achieved with 1SF, with removal efficiencies of 93% and 82%, respectively. The operating cost of the 2SF was slightly higher than the (1SF), at 0.738 ($/m3) and 0.660 ($/m3), respectively. The current efficiency and Ohmic drop (ohm) were also higher for the 2SF than the 1SF. The order of the 1SF and 2SF was first-order, and both configurations were exothermic. The study provides valuable insights for enhancing COD removal via EC process including Two-Sided Finned cathode due to the larger active area provided by the 2SF design then the enhancement of providing huge amount of hydroxide ions required to increase electro-coagulants quantity compared to that provided by using One-Sided Finned cathode.