The removal of COD in industrial wastewater by electro-persulfate process using central composite design

The untreated wastewater potentially can be a significant environmental challenge, which requires an effective treatment before discharging into the environment. This paper aimed to study and optimize the removal of the chemical oxygen demand (COD) from industrial wastewater using Electro-Persulfate (EPS) activated by iron electrodes. The Central Composite Design (CCD) was employed for experimental design and statistical analysis of independent operational parameters, including persulfate to COD ratio, pH, treatment time, and applied current on the removal of COD in the wastewater. According to the results of Response Surface Methodology (RSM), the optimal conditions for each critical variable were as follows: S2O82-/COD = 1.92, pH at 9, applied current at 3A, and 40 min of treatment time. The maximum efficiency in the experimental and predicted COD removal was 80 and 78.85%, respectively. The results of Analysis of variance (ANOVA) demonstrated high determination coefficient quantities (R-2 =0.96, Predicted R-2 =0.86 and Adjusted R-2 =0.92) which validated the reliability of the second-order regression model. The amounts of other parameters including total dissolved solids (TDS), total organic carbon (TOC), and biological oxygen demand (BOD) were decreased considerably as well.

Automated summary

This study aimed to optimize the removal of COD from industrial wastewater using electro-persulfate (EPS) activated by iron electrodes. The results showed that under the optimal conditions, the maximum efficiency of COD removal was 80%.