Performance Analysis of Partial Nitrification Fillers under Different Ammonia Concentration and Dissolved Oxygen Conditions

This study explores the long-term, efficient, and stable performance of partial nitrification (PN) achieved through gel immobilization technology for ammonia-oxidizing bacteria (AOB).Comprehensive research was conducted on the PN characteristics of the packing material under high and low ammonia concentrations and varying apparent dissolved oxygen (DO) conditions.We investigated the microbial community structure within the packing material at different DO levels and identified the optimal DO concentration for biologically active partial nitrification fillers, analyzing the impact of the surface gel layer on oxygen transfer.Results indicate that the biological activity of the packing material can rapidly initiate and exhibit strong shock resistance and adaptability.Once stabilized, the nitrite accumulation rate (NAR) exceeds 95%, with a maximum ammonia oxidation rate of 53.7 mg/(Lh).The high abundance of AOB and the dynamic changes in the functional microbial community are the main factors influencing the stable and efficient partial nitrification performance.The competition among microorganisms and the combined effect of the surface gel effectively inhibit the growth of nitriteoxidizing bacteria (NOB), ensuring the dominance of AOB.This research provides a reliable theoretical basis for the practical application of partial nitrification processes.