Functional genera for efficient nitrogen removal under low C/N ratio influent at low temperatures in a two-stage tidal flow constructed wetland

Qingqing Pang; Wenwen Xu; Fei He; Fuquan Peng; Xiang Zhu; Bin Xu; Jianghua Yu; Zewei Jiang; Longmian Wang

doi:10.1016/j.scitotenv.2021.150142

Functional genera for efficient nitrogen removal under low C/N ratio influent at low temperatures in a two-stage tidal flow constructed wetland

Sci Total Environ. 2022 Jan 15:804:150142. doi: 10.1016/j.scitotenv.2021.150142. Epub 2021 Sep 6.

Authors

Qingqing Pang¹, Wenwen Xu², Fei He¹, Fuquan Peng¹, Xiang Zhu¹, Bin Xu¹, Jianghua Yu³, Zewei Jiang⁴, Longmian Wang⁵

Affiliations

¹ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China.
² Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
³ Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
⁴ College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, PR China.
⁵ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China. Electronic address: wlmian@sina.com.

PMID: 34509836
DOI: 10.1016/j.scitotenv.2021.150142

Abstract

A two-stage tidal flow constructed wetland (referred to as TFCW-A and TFCW-B) was used to treat low chemical oxygen demand/total nitrogen (COD/TN or simply C/N) ratio influent at low temperatures (<15 °C). The influence of the flooding-resting time (A: 8 h-4 h, B: 4 h-8 h) and effluent recirculation on nitrogen removal and microbial community characteristics were explored. TFCW-B achieved optimal average nitrogen removal efficiency with effluent recirculation (96.05% ammonium nitrogen (NH₄⁺-N); 78.43% TN) and led to nitrate nitrogen (NO₃^--N) accumulation due to the lack of a carbon source and longer resting time. Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were inhibited at low temperatures. Except for nrfA, AOA, AOB, narG and nirS were separated by the flooding-resting time rather than by spatial position. Furthermore, the dominant genera in TFCW-A were Arthrobacter, Rhodobacter, Pseudomonas, and Solitalea, whereas prolonging resting time promoted the growth of Thauera and Zoogloea in TFCW-B. Spearman correlation analysis showed that Zoogloea and Rhodobacter had the strongest correlations with other genera. Moreover, the NH₄⁺-N concentration was significantly positively influenced by Arthrobacter, Rhodobacter, Pseudomonas, and Solitalea but negatively influenced by Thauera and Zoogloea. There was no significant correlation between TN and the dominant genera. This study not only provides a practicable system for wastewater treatment with a low C/N ratio but also presents a theoretical basis for the regulation of microbial communities in nitrogen removal systems at low temperatures.

Keywords: Low temperature; Nitrogen removal; Two-stage tidal flow constructed wetland; narG; nirS.

MeSH terms

Ammonium Compounds*
Denitrification
Nitrogen
Temperature
Waste Disposal, Fluid
Wetlands*

Substances

Ammonium Compounds
Nitrogen