Lipid rich kitchen waste: analytic characterization, anaerobic digestion, and mass balances

The conversion of kitchen waste (KW) to biogas is an alternative substrate for anaerobic digestion due to its high volatile solids content, primarily composed of carbohydrates, proteins, and lipids. This study characterizes KW and model kitchen waste (MKW) to understand the anaerobic digestion process, monitoring intermediates such as volatile organic acids (VOAs) and final products like methane and carbon dioxide. The research highlights the variability in waste composition and the impact of different substrate fractions on process dynamics. Notably, the study finds that KW and MKW exhibit similar biogas and methane dynamics, with no observed inhibition even at high loadings. The analysis also reveals atypical dynamics of C3 VOA, suggesting further investigation into the reasons behind this phenomenon. Overall, the study emphasizes the importance of mass balances and the potential of COD balances for monitoring high-fat wastes, contributing to a better understanding of the anaerobic digestion process.