Study on the expanded culture and kinetics of anammox bacteria in the upper flow packed bed

Anaerobic ammonium oxidation (Anammox) technology has a unique advantage in the simultaneous treatment of ammonia nitrogen and nitrite nitrogen. Kinetics models were usually utilized to identify an expanded anammox reactor to be efficient and stable. And the high-throughput sequencing test had been utilized to identify different kinds of anammox bacteria for a long time. The Monod model showed that the theoretical maximum total nitrogen removal concentration was near 1700 mgN/(gVSS·d). Nitrite nitrogen was an obvious inhibitor of anammox bacteria based on the kinetics results of both Monod model and Haldane model. The Luong model indicated that there was still a great potential of improvement of total influent nitrogen concentration. And the Modified Stover-Kincannon Model and Grau second-order model were applicable to describe stable operation of the reactor. While, high-throughput sequencing test results indicated that the bacteria Candidatus Kuenenia was the dominant anammox bacteria of this reactor, which meant that Candidatus Kuenenia was more applicable for operation condition of the reactor. Interestingly, the original bacterium Candidatus Anammoxoglobus was gradually eliminated during the operation phase. The reactor still had a quite high potential for the removal of the substrate. In the process of culture expansion, the phenomenon of bacterial species alteration had emerged, which was relatively rare in previous papers.