Study on removal rate of pollutants and plant growth in subsurface and surface flow constructed wetlands.

A pilot experiment was conducted to compare the removal rate of pollutants,plant growth and biomass of species in gravel-bed subsurface flow constructed wetland and soil-bed surface flow constructed wetland treated with larger water load.The results showed that the wastewater purification effect in subsurface flow constructed wetland was superior to that in surface flow constructed wetland with the same retention time.Root biomass in surface flow constructed wetland was significantly higher than that in subsurface flow constructed wetland,while the shoot growth in surface flow constructed wetland was nearly equal to that in subsurface flow constructed wetland.The results suggested that there wasn't correlative relaxation between purification effect and root biomass.