Electrochemical pretreatment of distillery wastewater using aluminum electrode

Abstract

Electrochemical (EC) oxidation of distillery wastewater with low (BOD5/COD) ratio was investigated using aluminum plates as electrodes. The effects of operating parameters such as pH, electrolysis duration, and current density on COD removal were studied. At a current density of 0.03 A cm−2 and at pH 3, the COD removal was found to be 72.3%. The BOD5/COD ratio increased from 0.15 to 0.68 for an optimum of 120-min electrolysis duration indicating improvement of biodegradability of wastewater. The maximum anodic efficiency observed was 21.58 kg COD h−1 A−1 m−2, and the minimum energy consumption observed was 0.084 kWh kg−1 COD. The kinetic study results revealed that reaction rate (k) decreased from 0.011 to 0.0063 min−1 with increase in pH from 3 to 9 while the k value increased from 0.0035 to 0.0102 min−1 with increase in current density from 0.01 to 0.03 A cm−2. This study showed that the COD reduction is more influenced by the current density. The linear and the nonlinear regression models reveal that the COD reduction is influenced by the applied current density.