Evaluation of methane production and macronutrient degradation in the anaerobic co-digestion of algae biomass residue and lipid waste

Algae biomass residue was co-digested with lipid-rich fat, oil, and grease waste (FOG) to evaluate the effect on methane yield and macronutrient degradation. Co-digestion of algae biomass residue and FOG, each at 50% of the organic loading, allowed for an increased loading rate up to 3 g VS/L d, resulting in a specific methane yield of 0.54 L CH4/g VS d and a volumetric reactor productivity of 1.62 L CH4/L d. Lipids were the key contributor to methane yields, accounting for 68–83% of the total methane potential. Co-digestion with algae biomass residue fractions of 33%, 50%, and 67% all maintained lipid degradations of at least 60% when the organic loading rate was increased to 3 g VS/L d, while synergetic effects on carbohydrate and protein degradation were less evident with increased loading.