Impact thermal and calcium oxide pretreatment on the anaerobic digestion of food waste: performance and carbon emissions

In this study, thermal and calcium oxide (CaO) pretreatment were used as a strategy to improve the performance of the anaerobic digestion of food waste. Meanwhile, the carbon emissions among the two strategies were evaluated. The results showed that both the two strategies could effectively promote the solubilization of organic matter in food waste and improve the hydrolysis rate of anaerobic digestion, which resulted in an increase of the methane yield. The highest methane yield (284.4 mL/g VS) was obtained in the group pretreated with 1.0 g/L CaO, which was increased by 23.8% compared with the control group. After the pretreatment, the anaerobic digestion pathway changed from acetotrophic methanogenesis to the co-dominated methanogenesis process by hydrogentrophic and acetotrophic. Meanwhile, CaO pretreatment had a better performance on the carbon emission which was increased by 23.75% compared with the control group.