Synergetic enhancement of biogas production from food waste

During the anaerobic digestion of food waste, the most significant parameters to focus on are optimizing efficiency, ensuring process stability, and minimizing environmental impact. In that regard, the present work reports the enhancement of hydrogen and methane generation using suitable catalysts to optimize the process efficiency. To provide stability and increase efficiency, the effects of copper oxide (CuO), calcium carbonate (CaCO3), calcium peroxide (CaO2), and zinc oxide (ZnO) as catalytic additives were experimentally evaluated using food waste and cow dung as substrates in separate batch reactors. The maximum hydrogen generation using CaO2 as an additive was 115.6 mL g-1 total solid (TS), which was 8.6% higher than the base sample, while ZnO showed a 10.4% reduction in hydrogen synthesis. Compared with the base reactor, methane production reached 161.2 and 129.06 mLg-1 TS with CaO2 and CaCO3, respectively, representing increases of 40% and 25%, respectively, whereas it was limited to 62.65 and 76.23 mLg-1 TS with CuO and ZnO, respectively, indicating decreases of gas generation by 35% and 21%, respectively. Finally, the physicochemical properties of the excreta from the reactors are suitable for use as biofertilizer, thereby minimizing environmental impact. The present research provides a novel approach to identify the technical requirements of the anaerobic digestion process using cow dung and food waste to enhance cumulative methane and hydrogen production.