Cold-pressed fruit and vegetable juice pomaces: decision making about their suitability for anaerobic digestion

Abstract

Cold-pressed juice is a fast-growing market due to new consumer demand. This industry generates large amounts of fruit and vegetable pomaces (FVP) that should be valorized. The main contribution of this work is the use of real data at an industrial level for the development of an approach to support the cold-pressed juice industry in making decisions regarding the suitability of different FVP for bioenergy recovery through anaerobic digestion. Multicriteria decision analysis was used during exploratory work to determine the study boundaries. The analysis considered different criteria that can affect the suitability of FVP as feedstock, such as its availability and physicochemical characteristics. To offer flexibility, two management routes were considered for the anaerobic digestion of FVP: (A) with no pre-treatment and (B) with mechanical pre-treatment. The theoretical biochemical methane potential of FVP was predicted for each route: for route A, it ranged from 410.5 to 412.3 mL CH₄ g_TVS⁻¹ and for route B it ranged from 386.9 to 465.4 mL CH₄ g_TSV⁻¹. Nevertheless, the low pH and high carbon-to-nitrogen ratio values obtained indicate that FVP should be used as a co-substrate in the anaerobic digestion process. The developed approach can be used and adapted to other types of agro-industry to promote the valorization of biowaste through co-digestion and increase the deployment of renewable energy.