AbstractThe 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 °C, the maximum hydrochar yield production was 58.2%, with a higher heating value of 10.75 MJ/kg. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.
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