Methane from mango industrial waste: Influence of pH and co-anaerobic digestion

Abstract

Agro-industries in Indonesia generate significant amounts of mango industrial waste (MIW). This research evaluated the potential of generating methane from Podang and Honey mango seed kernels, peels, and wastewater, which were collected from a dried fruit manufacturer. A biochemical methane potential (BMP) test was performed on the individual MIW components (mono-digestion) and mixtures (co-digestion). The BMP was highest for co-digesting Podang seed kernels and peels at a 1:1 ratio, with an average BMP of 0.112 m³/kg VS substrate. This was the only mixture that had synergistic effects. Crude fat and pH were significant in predicting methane output. All reactors were inhibited by pH with an average post-BMP pH of 4.26. This could be attributed to the acidic nature of MIW and accumulation of volatile fatty acids in the reactor. Future research should investigate the co-digestion of MIW with substrates that have higher crude fat content and pH.