In order to improve the ferrous ion-dependent nitrate removal (FeNiR) process, hexametaphosphate chelated ferrous ion was used as substrate to replace the free ferrous ion. With hexametaphosphate chelated ferrous ion as substrate, the influent pH was adjusted to 6.8, and as a result a higher effluent pH (7.2) was detected. The volumetric removal rate (VRR) of nitrate kept at 0.42 ± 0.03 kg-N/(m³∙d) for 48 days and the corresponding nitrogen removal efficiency was 94.39 ± 4.57%. After 88 days of cultivation, FeNiR granules became small because of the oligotrophic substrate. The transmission electron microscope (TEM) analysis showed that less iron encrustation was formed on the surface or in the periplasm of FeNiR cells. The linear curve of the living cell percentage versus time showed that the death rate of FeNiR cells with chelated ferrous ion as substrate was much lower than that with free ferrous ion as substrate (0.4210 vs 0.9221). Without iron encrustation, both the FeNiR activity and alkaline phosphatase (ALP) activity of FeNiR cells kept at high level and thus the efficiency of the FeNiR reactor kept stable and high. With hexametaphosphate chelated ferrous ion as substrate, the pH in bulk liquid was high (pH = 7.2) resulting in the high FeNiR rate, and less iron encrustation was formed around cells ensuring the stability of high FeNiR rate. Therefore, using hexametaphosphate chelated ferrous ion as substrate was an efficient way to improve the FeNiR process.

为了改善铁rrous离子依赖妮trate ř emoval（FeNiR）工艺，六偏螯合亚铁离子作为底物来替换自由亚铁离子。以六偏磷酸螯合的亚铁离子为底物，将进水pH值调节至6.8，结果检测到较高的出水pH（7.2）。的v olumetric ř emoval ř吃硝酸盐保持在0.42±0.03公斤-N的（VRR）/（米³∙d）处理48天，相应的脱氮效率为94.39±4.57％。培养88天后，由于贫营养性底物，FeNiR颗粒变小。透射电子显微镜（TEM）分析表明，FeNiR细胞表面或周质中形成的铁结壳较少。活细胞百分比与时间的线性曲线表明，以螯合的亚铁离子为底物的FeNiR细胞的死亡率远低于以游离亚铁离子为底物的FeNiR细胞的死亡率（0.4210对0.9221）。如果没有铁结壳，无论是FeNiR活动和人盐碱地pFeNiR细胞的hosphatase（ALP）活性保持在高水平，因此FeNiR反应器的效率保持稳定和较高。以六偏磷酸盐螯合的亚铁离子为底物，散装液体中的pH值很高（pH = 7.2），导致FeNiR率高，并且在电池周围形成的铁结壳较少，从而确保了高FeNiR率的稳定性。因此，使用六偏磷酸盐螯合的亚铁离子作为底物是改善FeNiR工艺的有效方法。