Ecological insight into deterioration of one-stage partial nitritation and anammox system during environmental disturbance

This study investigated the relationship between the performance and the ecological features of a one-stage partial nitritation and anammox disturbed by oxygen. The disturbance caused an irreversible deterioration of the nitrogen removal rate from 0.8 to 0.05 kg N/(m3 center dot d) although the anammox genera increased from 1% to 1.4%. Meanwhile, the richness and evenness reduced from 455 and 4.00 to 429 and 3.81, respectively, following a similar pattern to the community complexity. The community drifted and formed three distinct clusters during and after the disturbance. Furthermore, 234 of 634 operational taxonomic units in the community were depleted despite recovered diversity and complexity during long-term stable operation. In conclusion, the ecological fluctuation of the microbial community with decreasing resilience was the driving force that fatally collapsed the system performance. This study suggests that ecological features are conducive to the diagnosis, prediction, and optimization of a partial nitritation and anammox system.

Automated summary

This study investigated the relationship between the performance and ecological features of a one-stage partial nitritation and anammox system disturbed by oxygen. The disturbance resulted in an irreversible deterioration of nitrogen removal rate and reduced richness and evenness of the microbial community. Additionally, the community structure changed and 234 operational taxonomic units were depleted. The study highlights the importance of ecological features in diagnosing, predicting, and optimizing the performance of partial nitritation and anammox systems.