Decolorization of distillery spent wash effluent by electro oxidation (EC and EF) and Fenton processes: A comparative study

In this study, laboratory scale experiments were performed to degrade highly concentrated organic matter in the form of color in the distillery spent wash through batch oxidative methods such as electrocoagulation (EC), electrofenton (EF) and Fenton process. The effect of corresponding operating parameters, namely initial pH: 2–10; current intensity: 1–5 A; electrolysis time: 0.5–4 h; agitation speed: 100–500 rpm; inter-electrode distance: 0.5–4 cm and Fenton's reagent dosage: 5–40 mg/L was employed for optimizing the process of spent wash color removal. The performance of all the three processes was compared and assessed in terms of percentage color removal. For EC, 79% color removal was achieved using iron electrodes arranged with 0.5 cm of inter-electrode space and at optimum conditions of pH 7, 5 A current intensity, 300 rpm agitation speed and in 2 h of electrolysis time. In EF, 44% spent wash decolorization was observed using carbon (graphite) electrodes with an optimum conditions of 0.5 cm inter-electrode distance, pH 3, 4 A current intensity, 20 mg/L FeSO4 and agitation speed of 400 rpm for 3 h of electrolysis time. By Fenton process, 66% decolorization was attained by Fenton process at optimized conditions of pH 3, 40 mg/L of Fenton's reagent and at 500 rpm of agitation speed for 4 h of treatment time.