Spatial distribution characteristics of environmental parameters and nitrogenous compounds in horizontal subsurface flow constructed wetland treating high nitrogen-content wastewater

This paper characterizes the spatial distribution of environmental parameters (dissolved oxygen, pH and oxidation–reduction potential) and nitrogenous pollutants (total nitrogen, ammonia and nitrate) in horizontal subsurface flow constructed wetland that has been used to treat artificial wastewater containing high concentration of ammonia and nitrate. With sufficient carbon source supplement, the nitrogen removal rates were found to be significantly related to the spatial distribution of oxygen content affected by the characters of the layer. Correlations among pH, oxidation–reduction potential and dissolved oxygen indicated that the nitrogen removal rates under study conditions mainly depended on the location of the layer and zone in the constructed wetland.