Utilization of trace metals for mitigating nitrous oxide generation in anaerobic digestion

In this study, trace metals were used to enhance the efficiency of anaerobic digestion and promote complete denitrification, thereby reducing nitrous oxide (N₂O) production. The potential for greenhouse gas production during anaerobic digestion was evaluated. The effects of supplementation of Cu, Al, Mo, Fe, KI, Co, and Ni on greenhouse gas emissions were investigated through the anaerobic digestion of food waste and sewage sludge mixtures. The addition of trace metals increased CH₄ production and decreased N₂O production. The N₂O mitigation rate ranged from 7.8% to 40.2% in all experiments with trace metals. The N₂O production was caused by incomplete denitrification due to high concentrations of hydrogen sulfide and organic matter. Trace metals contribute to enhancing the efficiency of anaerobic digestion and mitigating N₂O production.