Optimal combination of food waste and maize husk for enhancement of biogas production: Experimental and modelling study

• Optimum combination of 75% FW and 25% MH occurred in digester B.
• Increase in MH above 25% decreased biogas production.
• Post hoc Test in ANOVA showed a significant difference in digesters’ yields.
• Gompertz model simulation results corroborated the experimental findings.

This study was focused on the optimization of biogas production from the co-digestion of food waste (FW) and maize husk (MH). The co-digestion of FW and MH at various mixture ratios was carried out in digesters A to E at 37±1 °C. Digesters A, B, C, D and E contained FW: MH of (100:0; 75:25; 50:50; 25:75; 0:100) respectively. Results obtained showed that average biogas yields of 0.50 ± 0.04, 0.71 ± 0.07, 0.54 ± 0.05, 0.30 ± 0.03, and 0.24 ± 0.02 L/gVS were obtained from digesters A, B, C, D, and E respectively. The modified Gompertz modelling of the experimental data showed that digesters A, B, C, D, and E had latency (λλ) of 4.1, 4.9, 6.9, 7.4, and 10.6 days respectively. Digester B had the highest maximum specific biogas production RmRm, and maximum biogas production potential (A) of 0.50 L/gVS/day and 20.7 L/gVS respectively. The R2R2 values between experimental and simulation data ranged from 0.9913 to 0.9989 in all digesters. The Post hoc Test in ANOVA using the Least Significant Difference (LSD) confirmed that there were significant differences in the mean biogas yield from the different digesters. The study therefore shows that the best combination of FW and MH for enhanced biogas production occurred in digester B.