Synergistic co-digestion of agroindustrial biomass waste for optimized digestion for liquid biofertilizer recovery

The improvement of biomass energy systems through waste valorization strategies represents a promising approach for rural energy infrastructure development. This study evaluated synergistic anaerobic co-digestion approaches to optimize liquid biofertilizer recovery from diversified agroindustrial biomass waste streams in the Ecuadorian highlands. Three formulations were tested: cattle manure, panela-yeast-whey blend, and molasses-milk-ash-Medicago sativa combination using 200 L tubular biodigesters at 37°C under randomized complete block design. Physicochemical characterization followed NTE INEN standards with ANOVA statistical analysis. The optimized co-digestion formulation achieved substantial improvements in nutrient concentration. Organic matter content elevated to 48.8% while bioconversion efficiency maintained 92.4%. Process optimization reduced fermentation time without compromising volumetric yield, demonstrating enhanced biomass throughput for distributed energy applications. Statistical validation confirmed treatment superiority across all macronutrients (p < 0.001). This multifunctional biorefinery approach transforms heterogeneous agricultural residues into value-added products, advancing biomass valorization technologies and supporting circular bioeconomy development in smallholder energy systems.