Methane Production by Anaerobic Digestion of Spent Wash in Continuous Stirred Tank Reactor

Abstract

DSW (Distillery Spent Wash) is superfluous residual liquid waste produced during the process of alcohol production. It is one of the most critical environmental issues which cause pollution. Despite strictness of standards imposed on effluent quality, partially or untreated effluent very often finds access to surface and groundwater. The distillery wastewater becomes a serious risk to the water quality in several regions around the globe. The ever-increasing generation of DSW lead to take an attempt to investigate a few aspects of anaerobic digestion of spent wash collected from a distillery. In the present study CSTR (Continuous Stirred Tank Reactor) was used at laboratory scale. The study was carried out to evaluate the performance of CSTR after the effective startup and the gradual increment in the OLR (Organic Loading Rate). The maximum methane gas (CH4) of 71.68 ml at the OLR of 1.0g of COD (Chemical Oxygen Demand)/L was observed. The optimum COD removal efficiency of the CSTR was 91% corresponding to OLR of 1g of COD/L. The pH ranges from 7.1-7.3 gave better performance and maximum stability of the process. By increasing the ORL, the VFA (Volatile Fatty Acids) content was also increased and reached to the 1.5g COD/L. However, the removal efficiency of TS (Total Solids) increased at an accelerated rate of OLR.