Microbial mixotrophic denitrification using iron(II) as an assisted electron donor

Yuan Pan; Ying-Ying Fu; Ke Zhou; Tian Tian; Yu-Sheng Li; Han-Qing Yu

doi:10.1016/j.wroa.2023.100176

Microbial mixotrophic denitrification using iron(II) as an assisted electron donor

Water Res X. 2023 Mar 21:19:100176. doi: 10.1016/j.wroa.2023.100176. eCollection 2023 May 1.

Authors

Yuan Pan^{1

2}, Ying-Ying Fu¹, Ke Zhou¹, Tian Tian^{1

3}, Yu-Sheng Li¹, Han-Qing Yu¹

Affiliations

¹ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
² Anhui Province Key Laboratory of Industrial Wastewater and Environmental Treatment, Hefei 230026, China.
³ Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.

Abstract

Mixotrophic denitrification processes have a great potential in nitrogen removal in biological wastewater treatment processes. However, so far, few studies have focused on the mixotrophic denitrification system using Fe(II) as an exclusively assisted electron donors and the underlying mechanisms in such a process remain unclear. Furthermore, the mechanisms by which microorganisms cover carbon, nitrogen, phosphorus and iron in an iron-assisted mixotrophic system remain unrevealed. In this work, we explore the feasibility of using Fe(II) as an assisted electron donor for enhancing simultaneous nitrogen and phosphorus removal via long-term reactor operation and batch tests. The results show that Fe(II) could provide electrons for efficient nitrate reduction and that biological reactions played a predominant role in these systems. In these systems Thermomonas, a strain of nitrate-reduction Fe(II)-oxidation bacterium, was enriched and accounted for a maximum abundance of 60.2%. These findings indicate a great potential of the Fe(II)-assisted mixotrophic denitrification system for practical use as an efficient simultaneous nitrogen and phosphorus removal process.

Keywords: Fe(II)-assisted mixotrophic denitrification; Heterotrophic denitrification; Nitrate-reduction Fe(II)-oxidation bacterium; Nitrogen and phosphorus removal; Wastewater treatment.