The effects of Fe(III) and Fe(II) on anammox process and the Fe-N metabolism

Yao Chen; Fangxu Jia; Yingjie Liu; Wanrou Yu; Weiwei Cai; Xiaofan Zhang; Haodong He; Hong Yao

doi:10.1016/j.chemosphere.2021.131322

The effects of Fe(III) and Fe(II) on anammox process and the Fe-N metabolism

Chemosphere. 2021 Dec:285:131322. doi: 10.1016/j.chemosphere.2021.131322. Epub 2021 Jun 25.

Authors

Yao Chen¹, Fangxu Jia², Yingjie Liu¹, Wanrou Yu¹, Weiwei Cai¹, Xiaofan Zhang¹, Haodong He¹, Hong Yao¹

Affiliations

¹ Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Department of Municipal and Environmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, PR China.
² Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Department of Municipal and Environmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, PR China. Electronic address: jiafx@bjtu.edu.cn.

PMID: 34246098
DOI: 10.1016/j.chemosphere.2021.131322

Abstract

This study aims to compare the effects of different Fe stress on anammox (anaerobic ammonium oxidation) process, therefore seven identical reactors were operated under different Fe(II)/Fe(III) concentrations. After 38 days of operation, the anammox activity was highest (10.49 ± 0.41 mg-TN/(g-VSS·h)) under conditions of 5 mg/L-Fe(II), while under 30 mg/L-Fe(III) displayed severe inhibition. The results showed that continuous addition of 30 mg/L-Fe(III) would damage the composition of EPS (extracellular polymeric substances) and make anammox bacteria more sensitive to environmental stress. While high Fe(II) concentrations could result in precipitates encasing granular sludge, affecting substrate utilization. Moreover, the results of ΔNO₃^--N/ΔNH₄⁺-N indicated that Fe(II)-dependent nitrate reduction was induced in reactors added with Fe(II). OM27_clade and norank_f__Burkholderiaceae might be candidates for this process according to the correlation of genera and functional genes (based on the PICRUSt 2 functional prediction). Overall, this research is expected to provide new ideas to the effects of Fe(II)/Fe(III) on anammox and to the practical application of coupled system based on anammox in wastewater treatment.

Keywords: Anammox; Fe(II)-dependent nitrate reduction; Ferous; Ferric; Nitrogen removal.

MeSH terms

Bioreactors*
Ferric Compounds*
Ferrous Compounds
Nitrogen
Oxidation-Reduction

Substances

Ferric Compounds
Ferrous Compounds
Nitrogen