Enhancement of anaerobic digestion of Cellulosic fraction in cassava production wastewater by Microaeration

Abstract

Effects of microaeration on the anaerobic digestion of cassava wastewater with added cassava residue in the continuous stirred tank reactor (CSTR) system were studied. The CSTR system was operated at ambient temperature. The biogas was analysed for the production rate and compositions by a gas meter and gas chromatography (GC), respectively. In addition, the overflown liquid effluent was collected and analysed for chemical characteristics. Operating parameters were varied to achieve the optimum chemical oxygen demand (COD) loading rate, the maximum content of added cassava residue, and the optimum oxygen dosing on the degradation of the cellulosic fraction. The COD loading rate was varied from 0.604 to 2.500 kg/m3 d to determine the optimum COD loading rate without oxygen supply. The results showed that with the optimum COD loading rate of 1.710 kg/m3 d, the generated gas mainly composed of 74.42 % CH4 and 18.43 % CO2 with negligible amounts of nitrogen and oxygen. The addition of a small amount of oxygen played an important role in the methane production. Copyright © 2014, AIDIC Servizi S.r.l.