Performance evaluation and microbial community analysis of microaerobic pretreatment on thermophilic dry anaerobic digestion

In this study, micmaembic pretreatment (MP) was used to improve the system stability and biogas production performance of the thermophilic dry anaerobic digestion (AD). The results showed that proper MP made the AD have better methane-producing performance and the maximum cumulative methane production was 108.31 mL/g VS with an oxygen load of 5 mL/g VS, which was 13.20 % higher than that of control group (G1, 95.68 mL/g VS). Specific micmaerobic conditions promoted the generation of volatile fatty acid (VFA) and reduced propionic acid content in the digestive system. In addition, the volatile solid (VS) removal rate of the digestive substrates was improved in the presence of limited oxygen, which can reduce environmental risks. Microbial community diversity indicated that MP increased the relative abundance of Firmicutes to promote substrate hydrolysis and accelerated the growth of hydrogenotrophic methanogens to improve AD performance.