Effect of Different Factors on Nitrogen Removal Rate in Constructed Wetlands

Factors affecting total nitrogen (TN) removal rates in constructed wetland were investigated by intermittent operation in the subsurface flow (SSF) constructed wetland system.The results demonstrated that removal rates of TN increased with the rising of TN pollution load (1.40-12.40 g/m2) when the retention time was determined by 60% TN Phragmites australis-soil-slag system.TN removal rates were affected by total phosphorus load in case of higher TN load.TN removal rates in SSF Phragmites australis wetlands were greater than that in SSF Calamagrostis angnstifolia wetlands at the same experimental cycle.Effect of wetland substrates on TN removal rates varied with the pollutants loading in SSF constructed wetland system,plant species and plant-growing period.