Effects of influent C/N ratios on CO2 and CH4 emissions from vertical subsurface flow constructed wetlands treating synthetic municipal wastewater

► The effects of influent C/N ratios on GHG fluxes from VSSF CWs were investigated. ► The GHG fluxes at different influent C/N ratios were estimated by the CMB model. ► The measured GHG fluxes agreed with the predicted ones in the range C/N = 2.5:1-5:1. ► C/N ratios in the range of 2.5:1-5:1 range generated relatively low GHG fluxes. ► An influent of C/N = 5:1 achieved the greatest BNR efficiency with the lowest GHG flux.