Performance Evaluation of the Electro-Fenton Process for Distillery Wastewater Treatment

Abstract

A fair amount of India’s gross domestic product is contributed by distilleries, which are considered the backbone industries of India. Distilleries indeed play key roles in India’s exports. Distillery wastewater is recognized as one of the recalcitrant wastewaters, containing extremely high organic loading and having an adverse impact when released into the environment. The aim of the present study was to optimize the conditions required for attaining improved COD removal efficiency in distillery wastewater through an electro-Fenton (EF) process. The effect of various operating parameters, viz. H2O2 dosage (555–2220 mg L−1), spacing between the iron electrodes (2–6 cm), electrode dipping area (35–65 cm2), initial pH (2–9), and constant voltage supply (5–15 V), were investigated by carrying out the EF process in batch mode. As a result of the EF study, COD removal efficiency of 79.5% for an initial COD of 5500–6000 mg L−1 was achieved for the distillery wastewater under the condition of 1665 mg L−1 H2O2, 2.5 cm of spacing between the electrodes, 55 cm2 of electrode dipping area, pH 3, and constant voltage supply of 5 V. In the same study, the kinetics of the process was also investigated, and it obeyed the pseudo-first-order reaction. The EF process effectively degrades complex organic compounds in distillery wastewater into simpler, potentially less toxic substances, as demonstrated by gas chromatography–mass spectrometry (GC-MS) analysis and pathway elucidation. The central composite design (CCD) of the response surface methodology (RSM) model was used to optimize the COD removal in distillery wastewater through the EF process. In line with the batch experimental results, RSM projections also indicated that the optimum conditions required for attaining a maximum of 70.8% COD removal efficiency in distillery wastewater are found to be 1402 mg L−1 H2O2 dosage, 3 cm electrode spacing, 60 cm2 dipping area, 5 V voltage, and pH 2.18. The research data supported the conclusion that the EF process is feasible for distillery wastewater treatment, which preferably can be applied extensively.