Anaerobic ammonium oxidation (anammox) pathway is sensitive to organic matter, and its recovery requires reliable evidence regarding the dominance of anammox in N-removal. This study showed that the anammox process deteriorated, with N-removal efficiencies rapidly decreasing from 87.2 to 45.7% when reactors were exposed to COD shocks of 1.12, 2.24 and 3.36 g L-1 (COD/N ratio 2, 4 and 6). Comprehensive assessments of water quality, microbial characteristics and isotope analysis were adopted to investigate anammox recovery. Operational performance took 8-20 days to recover; anammox relative abundance recovered after 20 days, based on the results of fluorescence in situ hybridisation and quantitative PCR; and the anammox pathway contributed to 80.0-91.5% of N-loss 40 days after COD shock terminated, based on the results of the isotope labelling experiment. Therefore, a complete recovery required 40 days. The isotope labelling method supplied a reliable reference for recovery assessment of anammox system in real-world applications.

中文翻译：

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使用水质，分子生物学和同位素标记分析评估高COD负载后厌氧氨氧化途径的恢复。

厌氧铵氧化（anammox）途径对有机物敏感，其回收需要可靠的证据证明厌氧菌在脱氮中的优势。这项研究表明，当反应堆暴露于1.12、2.24和3.36 g L-1的COD冲击（COD / N比为2、4和6）时，厌氧氨氧化过程恶化，脱氮效率从87.2％迅速降低至45.7％。通过对水质，微生物特性和同位素分析的综合评估来研究厌氧氨氧化的回收率。操作性能需要8到20天才能恢复；根据荧光原位杂交和定量PCR的结果，厌氧氨氧化菌的相对丰度在20天后恢复。COD休克终止40天后，厌氧氨氧化途径占N损失的80.0-91.5％，根据同位素标记实验的结果。因此，完全恢复需要40天。同位素标记法为实际应用中的厌氧氨氧化系统的回收评估提供了可靠的参考。