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| Influence of different plants and hydraulic loading on the nitrogen and phosphorus removal of constructed wetlands |
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Abstract Through the use of six kinds of surface flow (SF) and subsurface flow (SSF)constructed wetland plants in comparative experiments, the variation of hydraulic loading (HL) for the different plant constructed wetland of treatment rate was analyzed, and the optimal HL and removal rate of the 6 different plants in SF and SSF constructed wetland were got. Theoretical optimal HL, removal rate, the actual optimal HL and TP, TN removal in unit area of constructed wetland were calculated. The results show that TP, TN removal efficiency of the SF and SSF constructed wetlands with 6 plants increased with the decrease of HL, different plants, different levels of treatment. And the removal rate of SF constructed wetland were lower than SSF. The TP, TN removal rate of SF was lower than SSF and TP removal rate was higher than TN. In SF, the TP, TN removal rate of Scripus Validus reducing level was decreased maximum and the TP removal of Oenan the javan ica reducing level was decreased minimum, the TN removal rate of Canna ChinenesisW was decreased minimum. In SSF, the TP removal rate of Canna ChinenesisW reducing level was maximum, Oenan the javan ica reducing level was minimum and the TN removal rate of Phragmites Aust ralis was maximum, and Eichhornia crassipes was minimum. Meanwhile, the average optimal HL for TP removal of SF and SSF constructed wetland with the 6 kinds of plants were 0.53, 0.68t/(m2×d), respectively. The average optimal HL for TN rcmoval of SF and SSF constructed wetland with 6 kinds of plants were 0.47, 0.44t/(m2×d), respectively.
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Received: 18 February 2011
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