Biochemical methane potential (BMP) of vinegar residue and the influence of feed to inoculum ratios on biogas production

Abstract

Vinegar residue, a typical agro-industrial by-product in the vinegar production process, constitutes a huge environmental problem in China. Though utilization of vinegar residue has drawn much attention, there is still no effective, economical, and environmentally friendly method to deal with it. Anaerobic digestion is an effective method widely used in organic waste processing which might be an alternative to convert this acidic waste into biogas energy. A biochemical methane potential assay was conducted, and the influence of different feed to inoculum ratios (F/I) was determined. The highest methane yield of 242.69 mL g VS-1 was achieved at a F/I of 1, while the lowest methane yield of 182.94 mL g VS-1 was obtained at a F/I of 6. The TVFA/TA ratio was higher than the limiting value (0.4) at F/I ratios of 5 and 6, which demonstrated destabilization during the anaerobic digestion process. The modified Gompertz equation was developed to calculate the cumulative methane yields from different F/I ratios. The results suggested that the vinegar residue had extensive potential in biogas production and anaerobic digestion as a promising method that may be applied to deal with such waste, thus it is worth doing further research in the future.