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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Publications at this Location » Publication #396987
Research Project: Improving Soil and Water Productivity and Quality in Irrigated Cropping Systems

Location: Water Management Research

Title: Factors influencing gaseous emissions in constructed wetlands: A meta-analysis and systematic review

Author
item HU, SILE - Northeast Institute Of Geography And Agronomy, Cas
item ZHU, HUI - Northeast Institute Of Geography And Agronomy, Cas
item Banuelos, Gary
item SHUTES, BRIAN - Middlesex University London
item WANG, XINYI - Northeast Institute Of Geography And Agronomy, Cas
item HOU, SHENG - Northeast Institute Of Geography And Agronomy, Cas
item YAN, BAIXING - Northeast Institute Of Geography And Agronomy, Cas

Submitted to: International Journal of Environmental Research and Public Health
Publication Type: Review Article
Publication Acceptance Date: 2/17/2023
Publication Date: 2/22/2023
Citation: Hu, S., Zhu, H., Banuelos, G.S., Shutes, B., Wang, X., Hou, S., Yan, B. 2023. Factors influencing gaseous emissions in constructed wetlands: A meta-analysis and systematic review. International Journal of Environmental Research and Public Health. 20(5). Article 3876. https://doi.org/10.3390/ijerph20053876.
DOI: https://doi.org/10.3390/ijerph20053876

Interpretive Summary:

Technical Abstract: Constructed wetlands (CWs) are an eco-technology for wastewater treatment and are applied worldwide. Due to the regular influx of pollutants, CWs can release considerable quantities of greenhouse gases (GHGs), ammonia (NH3), and other atmospheric pollutants like volatile organic compounds (VOCs) and hydrogen sulfide (H2S), etc. These compounds will aggravate global warming, degrade air quality and even threaten human health. However, there is a lack of understanding about factors affecting the emission of these gases in CWs. In this study, we applied meta-analysis to quantitatively review the main influencing factors on GHG emissions in CWs, while the emission of NH3, VOCs, and H2S were qualitatively assessed. Meta-analysis indicates that horizontal subsurface flow (HSSF) CWs emit less CH4 and N2O than free water surface flow (FWS) CWs. Moreover, the addition of biochar to the CW can mitigate N2O emissions compared to gravel-based CWs but biochar may increase CH4 emissions, while vegetated HSSF CWs emit less CH4 and N2O than unvegetated HSSF CWs. Polyculture CWs, irrespective of the number of plant species, stimulate CH4 emissions but have no influence on N2O emissions compared to monoculture CWs. The influent wastewater characteristics (e.g., C/N ratio, salinity) and environmental conditions (e.g., temperature) can also impact GHG emissions. The NH3 volatilization in CWs is positively related to nitrogen concentration and pH value in the influent. High plant species diversity tends to reduce NH3 volatilization. Though VOCs and H2S emissions from CWs do not always occur, it should be a concern when using CWs to treat specific wastewaters containing hydrocarbon and acid, respectively. This study provides solid references for simultaneously achieving pollutant removal and reducing gaseous emission in CW and thereby reduce the transformation of water pollution contaminates into air contaminates.