Removal of Chromium from Electroplating Industry Wastewater Using Bioelectrochemical System: Kinetic Study and Statistical Analysis

Abstract

The hybrid bioelectrochemical systems (BES), a self-sustaining novel technology, was tested for evaluating its efficiency for removal of hexavalent chromium from electroplating industry wastewater. The BES reactor was designed and optimized for different parameters, such as substrate concentration, mixed liquor volatile suspended solids (MLVSS), hydraulic retention time (HRT), and chromium concentration. The concentration of hexavalent chromium [Cr(VI)] in the electroplating industries was found in the range of 0.43–48.7 mg/L. Whereas in the experiments Cr(VI) concentration, it varied from 10 to 50 mg/L (10, 20, 30, 40, and 50 mg/L). The BES demonstrated 87.88% of Cr(VI) removal at an influent concentration of 50 mg/L and HRT of 24 h. Correlation analysis revealed that chromium removal efficiency (CRE) was directly proportional to substrate consumption, voltage generation, MLVSS, and HRT, and had an inverse relation with chromium concentration in the cathode chamber. Principal component analysis (PCA) extracted two principal components that together explained approximately 82.15% of data variability (PC1: 62.73%; PC2: 19.41%). The kinetics of substrate degradation and chromium removal was assessed, revealing that substrate degradation and chromium removal can be better described by a first-order kinetic model.