Multi-angle evaluation of the anaerobic digestion of Molasses vinasse using two different feeding patterns

Abstract

Molasses vinasse (MV) is a waste burden in alcohol production due to its high organic matter content. However, it represents a potential source of energy recovery if adequately treated. In this study, two feeding patterns (pulse feeding: 8 ​L/4 ​h and semi-continuous feeding: 8 ​L/23 ​h) were evaluated for their effects on MV anaerobic digestion from multiple perspectives in a laboratory-scale reactor. The results demonstrated that semi-continuous feeding not only achieved a higher soluble chemical oxygen demand (sCOD) removal rate of 78.48% but also increased the production of biogas and methane by 20.04% and 51.48%, respectively. In addition, the chemical composition analysis suggested that the semi-continuous feeding pattern degraded the majority of lignin/CRAM and aromatic substances more effectively than the pulse feeding pattern. Moreover, the microbial analysis revealed that semi-continuous feeding increased the number of dominant bacteria, including Chloroflexi, Synergistetes, and Cloacimonetea, and methanogenic archaea, including Methanosaeta and Methanosarcina. The findings of this study, therefore, confirm that the semi-continuous feeding model is more effective and has good application potential, laying the groundwork for the MV anaerobic industrial processes.