Microbial Community Analysis and Effects of Fe(II)/Mn(II) Ratio on Denitrification in the Mixotrophic Biological Reactor

Abstract

In this study, the denitrification performance of the mixotrophic biological reactor was investigated under varying Fe(II)/Mn(II) molar ratio conditions. Results indicate that the optimal nitrate removal ratio occurred at an Fe(II)/Mn(II) molar ratio of 9:1, pH of 7, with an HRT of 10 h. When the reactor was performing under optimal conditions, the nitrate removal reached 100.00% at a rate of 0.116 mmol·L⁻¹·h⁻¹. The proportion of oxidized Fe(II) and Mn(II) reached 99.29% and 21.88%, respectively. High-throughput sequencing results show that Pseudomonas was the dominant species in the mixotrophic biological reactor. Furthermore, the relative abundance of Pseudomonas and denitrification performance was significantly influenced by variation in the Fe(II)/Mn(II) molar ratio.

Keywords:

• Mixotrophic biological reactor
• denitrification
• Fe(II)/Mn(II) molar ratio
• microbial community diversity

Additional information

Funding

This research work was partly supported by the National Natural Science Foundation of China (NSFC) (No.51678471). Key Scientific Technological Innovation Team Plan of Shaanxi Province (No. 2017KCT-19-02). State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology) (No.2017TS06), the Foundation for Creative Research Groups of China (No.50821002).