A parametric experimental validation of a biorefinery concept based on anaerobic digestion of fruit and vegetable waste

The goal of this paper was to assess the possibilities for one-stage reactor anaerobic digestion processing of fruit and vegetable biomass within a biorefinery concept for optimum products. Co-digestion was the simplest strategy to implement to increase product yield among the variables tested (pH, ultrasonification, and co-digestion). Methane yields from co-digestion of fruit and vegetable waste (FVW) and pig manure (PM) ranged from 318 to 434 NmL /g VS, with the highest yield (434 NmL /g VS) achieved at a co-digestion ratio of FVW75:PM25, representing a 20% increase over the methane production from FVW alone. The pH value was determined to be the most effective variable for enhancing methane production, with pH = 8 producing the maximum cumulative methane yield of 497 NmL/g VS. There was no significant change in the composition of volatile fatty acids (VFA) with pH in terms of dominant product type; valeric acid was the predominant VFA synthesized at all starting pH values except pH = 12, where formic acid was the predominant acid formed. As a digestate post-treatment procedure, hydrothermal carbonization was combined with anaerobic digestion. At 200 degrees C, the maximum hydrochar yield production was 58.2%, with a higher heating value of 10.75 MJ/kg. (c) 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.