Research on the Diversity of Nitrogen-Removing Microorganisms

This project developed an AOA enriched culture from wastewater through the application of stimulants and inhibitors, which was subsequently inoculated into moving bed biofilm reactors (MBBR). By implementing operational strategies featuring low ammonium loading, limited dissolved oxygen, and extended sludge retention time (SRT), we established an AOA dominated biofilm system capable of coupled nitrification-denitrification for nitrogen removal. The study systematically investigated the system's nitrogen removal performance under various operational conditions while examining the competitive and synergistic interactions among microbial populations to elucidate the fundamental nitrogen transformation mechanisms in AOA mediated coupled processes.Through comprehensive monitoring of N2O concentration dynamics within biofilms and evaluation of operational parameters on N2O production, the research employed advanced isotopic tracing techniques and molecular biology tools to unravel microorganism-specific N2O generation pathways. A mechanistic mathematical model was developed to characterize the symbiotic relationships among AOA, ammonia-oxidizing bacteria (AOB), and denitrifiers, along with their respective nitrogen removal pathways and N2O production mechanisms. This model served to predict the system's nitrogen removal efficiency and N2O emission potential, thereby guiding reactor optimization for achieving energy-efficient nitrogen removal with minimized N2O release. The findings provide both theoretical foundations and practical guidance for developing low carbon wastewater treatment technologies.