Influence of compositional and structural characteristics on food waste for biogas production

Food waste (FW) management by 'Waste to Energy' via anaerobic digestion (AD) is essential to reduce its carbon footprint and environmental impact. Present study aims to provide insights in understanding physicochemical characteristics of three different rice-based cooked FW for biogas production through AD. Three FWs used for the study are vegetables with lentils (VFW), leafy vegetables (LFW), and chicken (MFW). From the results, it is observed that total solids and ash content of VFW are higher than LFW & MFW, with oxygen demand being low in VFW. Dominating Functional groups in LFW, MFW, and VFW are complex organic compounds, low-fat compounds, and less complex organic compounds, respectively. Biogas production in VFW was higher overall, followed by MFW, and least in LFW. Correlation coefficient & cluster analysis reveals the significance of oxygen demand, pH, organic carbon, and volatile solids in biogas production. VFW and MFW, being less complex undergo maximum decomposition and produce more biogas (345 and 339 ml/g VSfed, respectively). LFW with high lignocellulose content produces less biogas (182 ml/g VSfed) due to its recalcitrant nature. It is also observed that deconstruction of the complex organic matters (cellulose and lignin) results in generation of more amorphous cellulose that is easily degradable during AD process. Overall, it can be concluded that VFW and MFW are highly suitable due to high degradability and biogas production. Hence, combination of these FWs with and without pretreatment can be used for upgrading biogas generation can be carried out in future studies.

Automated summary

FW management through AD is important to reduce its carbon footprint. This study investigated the physicochemical characteristics of three rice-based cooked FWs for biogas production. Results showed that VFW had higher total solids and ash content, while LFW had the least biogas production due to high lignocellulose content. VFW and MFW were found to be highly suitable for biogas production due to their high degradability.