title: Effects of influent C/N ratios on CO2 and CH4 emissions from vertical subsurface flow constructed wetlands treating synthetic municipal wastewater.
abstract: Greenhouse gases (GHG) emissions from constructed wetlands (CWs) can mitigate the environmental benefits of nutrient removal because reduced water pollution could be replaced by emission of GHG. Therefore, the GHG (CO(2) and CH(4)) fluxes of vertical subsurface flow constructed wetlands (VSSF CWs) under different influent C/N ratios of synthetic municipal wastewater were analyzed directly by GHG flux measurements, and estimated by carbon mass balance (CMB) over a 12 month period. The VSSF CWs system achieved the highest biological nutrient removal (BNR) efficiency between C/N ratios of 5:1 and 10:1 across all kinds of pollutants. Variation in influent C/N ratios dramatically influenced GHG fluxes from the VSSF CWs system. The GHG flux measured in situ agreed with those predicted by the CMB model and represented relatively low GHG fluxes when C/N ratios were between 2.5:1 and 5:1. It was determined that the optimum C/N ratio is 5:1, at which VSSF CWs can achieve a relatively high BNR efficiency and a low level of GHG flux.
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433, PR China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yan
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D012722:Sewage
chemical_list: D012722:Sewage; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen; D008697:Methane