Current Research in Green and Sustainable Chemistry (Jan 2022)
Biomethane potential and physicochemical characterization of cassava vinasse from ethanol distillery
Abstract
In this study, the biochemical methane potential (BMP), biodegradability index (BI), competitiveness index (CI), physicochemical properties and elemental compositions of cassava vinasse (CV) obtained from an ethanol distillery were investigated using experimental as well as instrumental analyses. Results showed that at room temperature of 28 °C, the CV was very watery with a specific gravity of 1.03. The relatively high Chemical Oxygen Demand, COD (62000–736500 mg/l) and Biochemical Oxygen Demand, BOD (21620–25000 mg/l); acidic pH (4.2–4.8) and cyanuric acid content (386–450 mg/l), emphasized its potential as a pollutant when discharged directly on land and water. A volatile solids content, VS (71580–72250 mg/l) and brix (5.9% sucrose) respectively indicate the presence of biodegradable organic matter and residual sugars in addition to many macro and micro-nutrients. At standard temperature and pressure (STP), BMP was experimentally determined to be 247.10 Nml/gVS which shows that the CV is a bioenergy resource. The results of BI and CI determination indicated that 82% of organic matter in CV is biodegradable and with a CI value above 10, there will be no competition between the methanogens and the sulphate-reducing bacteria (SRB) if the CV is subjected to anaerobic digestion (AD). This work improved existing knowledge and provided information for distillery operators and environmental regulators on alternative utilization and treatment routes for CV.