Kinetic Modeling and Performance Evaluation of Food Waste Anaerobic Digestion Using ADM1: Insights into Energy Yield, Process Stability, and Sensitivity

This paper presents a MATLAB realization of the Anaerobic Digestion Model No. 1 (ADM1) to simulate food waste mono-digestion in mesophilic, batch-mode mode. The model was validated using [1] data with a root mean square error (RMSE) of 0.31 L/day and a Nash Efficiency Score (NES) of 0.99 and exhibited high accuracy in predicting values. With a 90-day simulation period, the maximum daily biogas yield was 136.47 m³/day and methane yield remained constant at 73.21 m³/day. The gaseous composition produced—CH₄ ≈ 53.6%, CO₂ ≈ 45.9%, and H₂S ≈ 0.5% was consistent with values found in other research. The specific methane production (SMP) was 0.430 m³/kg VS, or 76.7% of the theoretical biochemical methane potential (BMP). System stability was achieved by reducing pH (from 7.69 to 7.30) and volatile fatty acid (VFA) levels (from 2,400 mg/L to 330 mg/L). One-At-A-Time (OAT) sensitivity analysis revealed hydrolysis rates for carbohydrates, proteins, and lipids as most critical parameters, while Monod constants had a negligible impact. While precise, the simplifications of the model—e.g., elimination of sulfate pathways, constant temperature, and empiric handling of pH indicate the opportunity for future improvement. This paper imposes the use of ADM1 to simulate open-access biogas and provides a reliable platform for simulating food waste valorization processes.