Performance of Combined Electrocoagulation-Advanced Electrochemical Oxidation Used for Oil Field Produced Water Treatment

Abstract

Considerable amounts of produced water (PW) are usually accompanied with theproduction of oil. This study proposed a combination of electrocoagulation (EC) - electro-Fenton (EF) process for oxidation organic compounds in PW to reduce the chemical oxygendemand (COD) to below regulation limits. The PW used in this study was collected fromoilfield in the Midland Oil Company. Pretreatment of the PW was conducted using batch ECtechnique with aluminum electrodes to eliminate the suspended and dissolved solids and toreduce the COD and treatment cost. Optimization of EC process revealed that optimum currentdensity, pH, and reaction time were 7.83 mA/cm2, 7.24, 20.40 minutes respectively. Underthese conditions the COD removal percentage was 73.97% starting from initial COD of 1730mg/l.Batch and continuous electro-Fenton processes were investigated using dimensionallystable anode Ti-RuO2/IrO2 and activated carbon fiber felt (ACFF) cathode. The effect ofcrucial process variables on COD removal efficiency was investigated using response surfacemethodology. A second order polynomial model equations were constructed and the resultswas analyzed by the analysis of variance (ANOVA). It was concluded that a combination ofelectrocoagulation followed by electro-Fenton process is effective for treating oilfieldproduced water and further improvement can be achieved by photo assisting the process. Atotal COR removal efficiency of 98% was achieved.