The investigation of shale gas wastewater treatment by electro-Fenton process: Statistical optimization of operational parameters

Shale gas is an alternative natural source of energy resulting from the anaerobic degradation of organics within shale formations. However, shale gas exploration is accompanied by shale gas wastewater production constituting a new source of pollution threatening the environment. Electro-Fenton process (EF) is used for the first time in this study as a new method for shale gas wastewater treatment where the optimum operating parameters of the the responses including COD, color, total phenol removal efficiencies and waste sludge volume were determined using a response surface methodology (RSM). Based on the analysis of variance (ANOVA), the coefficient of determination (R 2 ) was calculated and found to be above 0.94 for all the responses. The maximum removal efficiencies were found to be around 87.35%, 89.15%, and 91.75% for COD, color, and total phenol removal under the optimum conditions, respectively. The operational cost of the EF process applied to shale gas wastewater for COD removal at optimum conditions was determined to be 4.13 €/m 3 . The results indicated that the electro-Fenton seems to be an efficient treatment method for shale gas wastewater.