Fruit and vegetable wastes as co-substrates in anaerobic co-digestion

Azevedo, André; Lapa, Nuno; Moldão, Margarida; Gominho, Jorge; Duarte, Elizabeth

http://hdl.handle.net/10362/184699

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Resumo(s)

Global population growth has led to a significant increase in food waste, including Fruit and Vegetable Waste (FVW). Anaerobic co-digestion offers a sustainable way to valorise FVW, especially when combined with Municipal Sewage Sludge (MSS) to mitigate imbalances in their mono-digestion. This study investigates the effects of storage temperatures (10 °C and 25 °C, which represent Mediterranean climates with an Atlantic influence like Portugal) on the degradation of apple, carrot, and banana peels. Changes in physicochemical properties were assessed and anaerobic co-digestion batch assays with purées of fresh and stored FVW alongside MSS were performed. Results indicated that apple peels purées, at a 1:2 peel-to-water ratio, achieved over the double of volatile solids concentration compared to MSS, with each FVW type having a C/N ratio above 40. Storage at 10 °C significantly reduced the degradation of total and volatile solids, as well as chemical oxygen demand, with apple peels retaining the highest carbohydrate concentrations. Anaerobic co-digestion with fresh FVW boosted biogas and CH4 production by 19.5% and 15.2%, respectively. FVW storage at 10 °C further enhanced CH4 yield and decreased H2S content by 71% relative to MSS mono-digestion. These findings demonstrate that mild storage temperatures can improve biogas quality and yield by facilitating controlled FVW degradation.

Descrição

Funding Information: This research was funded by national funds from FCT – Fundação para a Ciência e a Tecnologia, I.P., through the doctoral scholarship “UI/BD/151370/2021″ attributed to Mr. André Azevedo, under the project “UIDB/04129/2020″ of LEAF (Linking Landscape, Environment, Agriculture and Food Research Unit), and PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects “UIDB/50006/2020″ and “UIDP/50006/2020″ attributed to the Associated Laboratory for Green Chemistry (LAQV). Publisher Copyright: © 2024

Palavras-chave

Biogas Municipal sewage sludge Natural degradation Peels’ storage Physicochemical properties Temperature Energy (miscellaneous) Environmental Science (miscellaneous) SDG 11 - Sustainable Cities and Communities