||Constructed wetlands (CWs) utilize the natural mechanisms in wetlands to remove pollutants by physical, chemical and biological processes. CWs are one of the ecological engineering methods to purity water quality and has been experimented to assess their capabilities to remove nutrients from eutrophic water bodies of lakes and reserviors. This|
study was carried out to compare the removal of nutrients between vegetated and unvegetated CWs. The vertical flow bed was placed in the upstream, while the horizontal subsurface flow bed was set in the
downstream. Cannaceae was selected to plant in the vegetated CWs. Two kinds of hydraulic retention time (HRT), 3 days and 7 days, were applied and compared with each other in this study.
The experimental results show that no significantly difference between vegetated and unvegetated systems. The removal efficiencies of SS, BOD,
NH3-N, TP are measure equal to about 80%, 75%, 80% and 65%, respectively, while the removal efficiencies of TN, OP, and COD were reached about 50% and larger. Both of the two systems show high
efficiencies for nutrient removal. In the comparison between the two kinds of HRT’s, the HRT controlled at 3 days presented higher removal efficiencies than that controlled at 7 days.