Estimating greenhouse gas fluxes from constructed wetlands used for water quality improvement

• Main Authors: Sukanda Chuersuwan, Pongthep Suwanwaree, Nares Chuersuwan
• Format: Article
• Language: English
• Published: Prince of Songkla University 2014-06-01
• Series: Songklanakarin Journal of Science and Technology (SJST)
• Subjects: greenhouse gas fluxes; methane; nitrous oxide; carbon dioxide; constructed wetlands; domestic wastewater
• Online Access: http://rdo.psu.ac.th/sjstweb/journal/36-3/36-3-14.pdf

Methane (CH4 ), nitrous oxide (N2O) and carbon dioxide (CO2 ) fluxes were evaluated from constructed wetlands (CWs) used to improve domestic wastewater quality. Experiments employed subsurface flow (SF) and free water surface flow (FWS) CWs planted with Cyperus spp. Results showed seasonal fluctuations of greenhouse gas fluxes. Greenhouse gas fluxes from SF-CWs and FWS-CWS were significantly different (p<0.05) while pollutant removal efficiencies of both CWs were not significantly different. The average CH4 , N2O and CO2 fluxes from SF-CWs were 2.9±3.5, 1.0±1.7, and 15.2±12.3 mg/m2 /hr, respectively, corresponding to the average global warming potential (GWP) of 392 mg CO2 equivalents/m2 /hr. For FWS-CWs, the average CH4 , N2O and CO2 fluxes were 5.9±4.8, 1.8±1.0, and 29.6±20.2 mg/m2 /hr, respectively, having an average GWP of 698 mg CO2 equivalents/m2 /hr. Thus, FWS-CWs have a higher GWP than SF-CWs when they were used as a system for domestic water improvement.