Anaerobic Followed by Aerobic Treatment Approaches for Spentwash Using MFC and RBC

Abstract

Distillery spent wash is the unwanted residual liquid waste generated during alcohol production and pollution caused by it is one of the most critical environmental issue. Distillery spent wash is one of the recalcitrant wastes having extremely high Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Suspended Solids (SS), inorganic solids, color and low in pH. Wastewater collection, storage, treatment and management are of prime importance towards environmental pollution prevention and control. In this concern, Microbial Fuel Cell (MFC) and Rotating Biological Contactor (RBC) were fabricated and further used to treat distillery spent wash. The present study was carried out at ambient environmental conditions. Different feed concentrations of 1,100 mg COD/L to 10,100 mg COD/L was fed to MFC which treated spent wash anaerobically. As the feed concentration increased the percentage reduction of COD, BOD and Dissolved Solids (DS) increased initially up to 6,100 mg COD/L and further reduction in the removal efficiencies were observed. The highest percentage of COD, BOD and DS removal were 64, 61.2 and 44.8 % respectively at 6,100 mg COD/L and was considered as optimal effluent. The average current (0.27 mA) and power density (18.35 mW/m2) values also proved to be higher at the feed concentration of 6,100 mg/L COD. This optimal effluent was treated further aerobically in RBC and obtained 84 % COD, 81 % BOD and 46.4 % DS removal. Hence MFC and RBC can be adopted to treat spent wash in an effective manner.