Effect of Punched-Hole Electrodes on the Performance of Electrocoagulation

Textile industries are water intensive and the effluent generated contains salts, dyes, and heavy metals as well as having a high biological oxygen demand (BOD) and chemical oxygen demand (COD), therefore it must be treated before being discharged into the aquatic environment to prevent its contamination. Electrocoagulation (EC) is a promising technique to treat domestic and industrial effluent, where in situ coagulants are produced by sacrificial dissolution of the anode by application of an electric current across the electrodes. The effect of punched-hole electrodes on the performance of EC—color removal efficiency (CRE), electrical energy consumption (EEC), and operating cost (OC)—was studied by varying the number and diameter of holes in the electrode. It was observed that the use of punched electrodes resulted in higher CRE, lower EEC, and lower OC as compared with plane electrodes. The difference in CRE obtained using plane and punched electrodes was found to increase with an increase in current. The effect of punched-hole electrodes on the treatment of real dye effluent was studied and COD removal of 78.79% was obtained using punched-hole electrodes as compared with 69.30% using plane electrodes. The EEC and the OC were found to be 0.5 kW·h/m3 and US$0.424/m3, respectively, for punched-hole electrodes.