Using electro-flotation/oxidation for reducing chemical oxygen demand, total organic carbon and total solids in vinasses

Abstract

The high chemical oxygen demand (COD) of vinasses from ethanol distilleries (greater than 130,000 mg/L) has led to exploring alternative treatments enabling their final disposition. The electro-flotation/oxidation of vinasses was thus experimentally evaluated regarding initial pH, electrolytic support (NaCl) and hydrogen peroxide concentration (H2O2), current density (CD) and several electrodes: iron, aluminum and galvanized steel. Its effect on reducing COD and total organic carbon (TOC) was studied, an initial 214,000 ppm COD value being reduced to 90,000 ppm, thereby representing a 58% reduction. The greatest reductions were achieved with galvanized steel electrodes, basic pH, 20 mA/cm2 and 60,000 ppm H2O2.