表面流人工湿地中水生植被的净化效应与组合系统净化效果

以无植物空白系统为对照,通过批量盆栽试验探讨了表面流人工湿地中不同类型水生植被(苦草(沉水植物)、水葫芦(浮水植物)、芦苇(挺水植物))的引人对富营养化水体不同污染物净化效果的影响;根据不同污染物去除的阶段性特征设计了分段式表面流人工湿地(好氧塘-水葫芦湿地一苦草湿地),并通过示范工程探讨了富营养河流的原位净化效果.研究表明,批量盆栽试验中,与无植物空白系统相比,芦苇的引入显著增加了表面流人工湿地的蒸发蒸腾量(为无植物空白系统的1.5倍),而水葫芦和苦草的引入则显著降低了表面流人工湿地的蒸发蒸腾量(分别为无植物空白系统的80%和30%);3种水生植物的引入均显著促进了CODcr、TN、NH 4-N的去除(与无植物空白系统相比),其中水葫芦系统具有最好的CODcr和TN去除效果(起始CODcr和TN水平分别为35.8 mg·L-1和6.86 mg˙L-1时,去除率分别为58.91%、76.67%),而苦草的引入则显著地促进了水体中氧化态氮的形成与积累.分段式表面流人工湿地的原位净化研究表明,水力负荷为6.2cm.d-1时,分段式表面流人工湿地对CODcr的净化效果较好,水力负荷过高会影响分段式表面流人工湿地的净化效果.

Pollutant purification performance of a surface flow constructed wetland planted with different aquatic macrophytes and their combination

The pollutant purification performance of a surface flow constructed wetland (SFCW) planted with different aquatic macrophytes,i.e.submerged(Vallisneria spiralis),floating(Eichhornia crassipes)and emergent(Phragmites australis)aquatic macrophytes,was investigated with non-vegetated SFCW as control.Subsequently,in-situ purification of eutrophication river water was investigated by a demonstration project of multi-stage SFCW (aerobic pond-Eichhornia crassipes wetland-Vallisneria spiralis wetland).In batch cultures,the evapotranspirations in Phragmites australis,Eichhornia crassipes and Vallisneria spiralis system were 150%,80% and 30% of that in the control system.The introduction of different aquatic macrophytes into the SFCW significantly improved the removal efficiencies of chemical oxygen demand(COD_Cr)and total nitrogen(TN).Eichhornia crassipes system had the highest COD_Cr and TN removal efficiencies,58.91% and 76.67%,respectively,at initial concentrations of COD_Cr and TN of 35.8 and 6.86 mg·L^-1,respectively.The application of Vallisneria spiralis significantly increased the accumulation of oxidized nitrogen(NO_x^--N)in the waterbody.Moreover,a demonstration project of the multi-stage SFCW achieved better COD_Cr removal efficiency at a hydraulic load of 6.2 cm·d^-1 that deteriorated at a higher hydraulic load.