铁腐殖酸（iron humic acid, Fe-HA）已被证实能够促进多种污染物的微生物代谢过程。考察了氮负荷（nitrogen loading rate, NLR）提升过程中Fe-HA对厌氧氨氧化（anaerobic ammonia oxidation, ANAMMOX）过程的影响，通过对脱氮性能、污泥特性以及菌群结构的分析，探究了Fe-HA对ANAMMOX过程影响的潜在机理。结果表明，NLR提升初期，添加Fe-HA的反应器（R_Fe-HA）脱氮性能均高于未添加Fe-HA的对照反应器（R_CON）；NLR提升稳定期，R_Fe-HA和R_CON的脱氮性能基本一致；R_Fe-HA的比厌氧氨氧化活性（specific ANAMMOX activity, SAA）均小于R_CON；R_Fe-HA的污泥浓度、平均粒径以及>0.85 mm的粒径占比也较R_CON高；此外，R_Fe-HA具有更高的胞外聚合物（extracellular polymeric substances, EPS）浓度，且EPS组分中疏水性的色氨酸类物质含量更高；第30天时，R_Fe-HA的Candidatus Kuenenia丰度高于R_CON。Fe-HA的添加促进了Candidatus Kuenenia的增殖，并引起EPS及其中色氨酸类物质分泌的增加，从而加速了颗粒污泥的形成，增大了污泥浓度和颗粒粒径，进而增强了NLR提升初期反应器的脱氮性能；然而，EPS的增加也会阻塞微生物与底物间的传质效率，降低SAA。

Iron humic acid (Fe-HA) has been proved that it can enhance the process of microbial metabolism for a wide range of pollutants. The effect of Fe-HA on the anaerobic ammonia oxidation (ANAMMOX) process during the increase of nitrogen loading rate (NLR) were investigated, and the potential mechanism of Fe-HA on the ANAMMOX process was explored through the analysis of nitrogen removal performance, sludge characteristics, and microflora structure. The results show that the nitrogen removal performance of R_Fe-HA is higher than that of R_CON during the initial stage after the NLR is increased. During the stabilization stage after the NLR is increased, the nitrogen removal performance of R_Fe-HA and R_CON is almost the same. The specific ANAMMOX activity (SAA) of R_Fe-HA is less than R_CON, while the sludge concentration, average particle size, and percentage of particle size >0.85 mm are higher than R_CON. Furthermore, R_Fe-HA has a higher concentration of extracellular polymeric substances (EPS) and a higher content of hydrophobic tryptophan-like substances in the EPS fraction. The abundance of Candidatus Kuenenia is higher in R_Fe-HA than R_CON at 30 d. The addition of Fe-HA promoted the proliferation of Candidatus Kuenenia and cause an increase in the secretion of EPS and tryptophan-like substances from granular sludge. The increase of EPS and tryptophan-like substances promoted the formation of granular sludge, increased sludge concentration and particle size, and enhanced nitrogen removal performance of the reactor during the initial stage of the NLR increase. However, the increase of EPS blocked the mass transfer efficiency between microorganisms and substrate and reduce the SAA of granular sludge.