Co-Digestion of Domestic Food Waste with Palm Kernel Cake for enhanced Biogas Production in Sokoto Metropolis, Nigeria

This study demonstrates that co-digesting domestic food waste with palm kernel cake can increase biogas yield by 32.6% and methane content to 67.8%, while improving digestate nutrient quality and highlighting the need for pathogen treatment before agricultural use.

Lubabatu Muazu Jodi

10/10/20261 min read

ABSTRACT

The accumulation of domestic food waste and agricultural by-products in Nigeria presents both environmental challenges and opportunities for renewable energy generation. This study investigated the enhancement of biogas production through anaerobic co-digestion of domestic food waste (DFW) with palm kernel cake (PKC), which is an abundant by-product of palm oil processing in Sokoto State. Batch anaerobic digestion experiments were conducted under mesophilic conditions (35 ± 2°C) for 40 days using rumen content as inoculum. Four mixing ratios of DFW:PKC were evaluated: 100:0 (control), 75:25, 50:50, and 25:75 based on volatile solids. The 50:50 ratio achieved the highest cumulative biogas yield of 612.4 ± 28.7 mL/g VS, representing a 32.6% increase over mono-digestion of DFW (461.8 ± 22.3 mL/g VS). Methane content peaked at 67.8 ± 2.1% for the 50:50 ratio compared to 58.3 ± 2.4% for DFW alone. Physicochemical characterization revealed that PKC supplementation, improved the carbon-to-nitrogen (C/N) ratio from 15.8:1 (DFW alone) to a corrected value of 19.8:1 at the optimal mixing ratio, approaching the ideal range for anaerobic digestion. Digestate from the co-digestion systems exhibited enhanced fertilizer quality, with nitrogen, phosphorus, and potassium concentrations increasing by 13.8%, 25.0%, and 23.1%, respectively (recalculated directly from the treatment means in Table 5), compared to DFW mono-digestion. The modified Gompertz model adequately described the cumulative biogas production kinetics (R² > 0.97). These findings demonstrate that co-digestion of domestic food waste with palm kernel cake significantly enhances biogas yield and quality while producing nutrient-rich digestate with potential as an agricultural soil amendment in Sokoto State, though pathogenic indicator organisms detected in the microbial analysis mean further pathogen-reduction treatment and agronomic validation are needed before agricultural use. The study provides empirical evidence supporting integrated waste-to-energy systems that simultaneously address organic waste management and energy poverty in Nigerian urban communities.

Keywords: Co-digestion, biogas, domestic food waste, palm kernel cake, anaerobic digestion, Sokoto, Nigeria

HOW TO CITE

Lubabatu, M. J. (2026). Co-Digestion of Domestic Food Waste with Palm Kernel Cake for enhanced Biogas Production in Sokoto Metropolis, Nigeria. Nexus Inventio: Journal of Science, Innovation and Education, 1(1), 53–63.

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