Greenhouse gas emissions and wastewater treatment performance by three plant species in subsurface flow constructed wetland mesocosms

Xin Chen; Hui Zhu; Baixing Yan; Brian Shutes; Defeng Xing; Gary Banuelos; Rui Cheng; Xinyi Wang

doi:10.1016/j.chemosphere.2019.124795

Greenhouse gas emissions and wastewater treatment performance by three plant species in subsurface flow constructed wetland mesocosms

Chemosphere. 2020 Jan:239:124795. doi: 10.1016/j.chemosphere.2019.124795. Epub 2019 Sep 6.

Authors

Xin Chen¹, Hui Zhu², Baixing Yan³, Brian Shutes⁴, Defeng Xing⁵, Gary Banuelos⁶, Rui Cheng¹, Xinyi Wang³

Affiliations

¹ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
² Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China. Electronic address: zhuhui@iga.ac.cn.
³ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China.
⁴ Urban Pollution Research Centre, Middlesex University, Hendon, London, NW4 4BT, UK.
⁵ State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China. Electronic address: dxing@hit.edu.cn.
⁶ USDA, Agricultural Research Service, San Joaquin Valley Agricultural Science Center, 9611 South Riverbend Avenue, Parlier, CA, 93648-9757, USA.

PMID: 31520977
DOI: 10.1016/j.chemosphere.2019.124795

Abstract

Greenhouse gas (GHG) emissions from constructed wetlands (CWs) have raised environmental concern and thus offset their environmental and ecological benefits. This study evaluated the influence of plant species, i.e., Canna indica (C. indica), Cyperus alternifolius (C. alternifolius), Phragmites australis (P. australis) and unplanted control, on GHG emissions, pollutant removal and associated microbial abundance in subsurface flow constructed wetland (SSFCW) mesocosms. C. indica outperformed the other tested plant species in pollutant removal, and the presence of plants irrespective of species enhanced the removal efficiencies of nitrogen, phosphorus and organics in SSFCW mesocosms compared to unplanted control. The greatest carbon dioxide (CO₂) flux (582.01 ± 89.25 mg/m²/h), methane (CH₄) flux (21.88 ± 2.51 μg/m²/h) and nitrous oxide (N₂O) flux (37.27 ± 15.82 μg/m²/h) were observed in mesocosms planted with C. indica, P. australis and C.alternifolius, respectively. Unexpectedly, the mcrA and pmoA genes were not detected in any mesocosms. For denitrifiers, the N₂O fluxes showed a significantly (p < 0.05) positive correlation with nirS and nirK genes abundance. The abundance of nosZ gene (ranged from 0.18 × 10⁴ to 0.75 × 10⁴ copies/mg gravel) and nosZ/(nirS + nirK) (ranged from 1.29 × 10^-4 to 2.12 × 10^-4 copies/mg gravel) in this study was lower than that in most reported studies. Regarding the global warming potential (GWP), the lowest value was observed in mesocosms planted with C. indica. In conclusion, C. indica is selected as the optimal plant species in this study due to its lower GWP and excellent pollutant removal performance.

Keywords: Functional genes abundance; Greenhouse gas emissions; Plant optimization; Subsurface flow constructed wetlands; Water purification.

MeSH terms

Carbon Dioxide / analysis
Denitrification
Greenhouse Gases / analysis*
Magnoliopsida / physiology*
Methane / analysis
Nitrogen / metabolism
Nitrous Oxide / analysis
Phosphorus / metabolism
Species Specificity
Waste Disposal, Fluid / methods*
Wastewater / analysis
Wetlands*

Substances

Greenhouse Gases
Waste Water
Carbon Dioxide
Phosphorus
Nitrous Oxide
Nitrogen
Methane