The Bioenhanced Effect of Biochar-Based Aerobic Denitrifying Bacteria on a Sequencing Batch Reactor under Different Stress Conditions

Biochar-based aerobic denitrifying functional bacteria (BADB) have the advantages of excellent biochar adsorption performance and high nitrogen removal efficiency. In this study, a sequencing batch reactor (SBR) system was employed to explore the impacts of various stress conditions on the pollutant removal efficiency and metabolic pathways of BADB. Additionally, the adaptation mechanisms and response patterns of functional bacteria under different stress conditions were revealed. The structure of the microbial community was analyzed through high-throughput sequencing. The research results indicated that aerobic denitrification bacteria had good growth and nitrate removal performance under various conditions. Aeration rate exhibited positive relationship with denitrification efficiency, and the effect was enhanced when the ion concentration increased. Carbon source type significantly influenced the denitrification efficiency of functional bacteria, among which sodium acetate showed the best effect. Within the appropriate C/N ratio range, greater amounts of carbon led to higher denitrification efficacies of functional bacteria. Sequencing results revealed the key role of Brachymonas in organic degradation and denitrification process, with a percentage of 13.9% in the system. This study can provide a reference for the optimization and utilization of biochar-based aerobic denitrification technology, which is of great significance for improving the quality of water environment.