Evaluation of the Simultaneous Effects of Fat, Light, and Reactor Geometry on Optimizing Biogas Production from Fruit and Vegetable Waste

Fruit and vegetable waste (FWV) is a rich organic resource for renewable energy production, but its inefficient management poses environmental challenges. This study aimed to optimize biogas production from these wastes via anaerobic digestion (AD). In ۱-liter batch reactors under thermophilic conditions (۵۵ °C), the effect of three key parameters was investigated: (۱) fat addition at three levels (fat-to-waste ratios of ۰.۵, ۱, and ۲), (۲) light exposure (clear vs. opaque reactors), and (۳) reactor geometry (standard vs. large cross-sectional area). Biogas production was measured by water displacement and methane by chemisorption. The highest biogas production (۱۱,۲۲۵ ml) and methane (۶,۵۱۷ ml) were obtained in treatment R۹ (reactor with large cross-sectional area and a ۱:۱ fat ratio, equivalent to ۴۵% total fat), while the lowest production was obtained in the control sample (R۱). Adding fat up to ۴۵% increased biogas production, but a concentration of ۶۰% led to a decrease in efficiency. Ambient light reduced biogas by ۲۳.۲۸%. In contrast, using a reactor with a large cross-sectional area increased biogas production by ۳۳.۲۴% compared to a clear reactor. Economic analysis showed the optimal process period to be ۱۷ days. The results show that optimization of substrate composition (۴۵% fat), light exclusion, and appropriate reactor geometry design (large cross-sectional area) is an effective strategy to significantly increase the technical and economic efficiency of biogas production from fruit and vegetable waste.

کلیدواژه ها:

Biogas ، Fruit and vegetable waste ، light effect ، fat ، reactor geometry