Enhancing nitrogen removal in source water with intermittent aeration: Improved performance of iron-reducing denitrifying bacteria
Honghong Guo, Na Li, Shuhong Xue, Xuanzi Zhangsun, Tinglin Huang, Haihan Zhang, Ben Ma
Abstract
Nitrogen pollution in source water bodies is an urgent problem faced both domestic and foreign countries. By taking inorganic electron donors as a breakthrough and constructing a chemical-biological coupled nitrogen removal theoretical and technical system, it is hopeful to solve this challenging problem. In this study, activated carbon (AC) as the carrier of iron-reducing aerobic denitrifying bacterial consortium coupled with sponge iron (SZVI) was used to construct aerobic denitrification system (ABS system), and attempted to strengthen nitrogen conversion through intermittent aeration (ABSI system). ABS and ABSI systems significantly removed 86.12% and 92.13% of total nitrogen. Nitrogen-transforming bacterial communities in ABSI system showed higher diversity and more favorable ecological niche. AC biofilm had a selective enrichment effect on iron reduction and aerobic denitrification bacteria, which helped to maintain the long-term denitrification effect and iron reduction. The ABSI system significantly increased the abundance of aerobic denitrification-related bacterial communities and functional genes, and the upregulation of genes pivotal for glycolysis processes and iron cycling in this system bolstered the microbial denitrification, thereby ensuring the production of autotrophic and heterotrophic electron donors, improving nitrogen removal efficiency in water. This study provides important new insight and theoretical support for in situ remediation of micro-polluted water sources.