潜流人工湿地处理低污染水对植物生长的影响

Effect of Low-Polluted Water Treatment on Plant Growth by Subsurface Flow Constructed Wetland

选择花叶芦竹(Arundodonax var.versicolor)、旱伞草(Cyperus alternifolius)、再力花(Thalia dealbata)、香蒲(Typha orientalis)、芦苇(Phragmites australias)5种挺水植物为对象,均匀种植于长13 m、宽4.5 m的砾石型潜流人工湿地,观测不同处理下低污染水的净化效果以及不同种植距离植株的株高、生物量和氮磷去除量。结果表明,与对照相比,5种植物湿地床对化学需氧量、NH_3-N、TN、TP的净化效果显著,但不同植物间处理效果不显著。随着种植距离增加,5种植物的株高、生物量、根冠比均呈下降趋势,单位面积生物量和氮磷去除量与种植距离间呈指数或对数下降关系。植物收割去除TN的大小顺序为:旱伞草>芦苇>再力花>花叶芦竹>香蒲,TP的大小顺序为:旱伞草>再力花>芦苇>花叶芦竹>香蒲;但从累计比例来看,两者积累效率大小顺序均为芦苇>再力花>旱伞草>花叶芦竹>香蒲。因此,处理低污染水人工湿地植物选择时,需要选择高氮磷积累量的物种,更应选择具有高氮磷积累效率的物种。

Five aquatic macrophytes plants, such as Arundo donax var. versicolor , Cyperus alternifolius , Thalia dealbata , Typha orientalis, Phragmites australias were selected and planted on gravel-type subsurface flow constructed wetlands with a length of 13 m and width of 4. 5 m. The plant height, biomass, nitrogen and phosphorus content at different distance and its purification effect were observed. The results showed that purification effect of COD, ammonia nitrogen, total nitrogen and total phosphorus of five plant system constructed wetland was significantly better than that without plant system. With the increase of planting distance, the growth, biomass and root-shoot ratio of five plant species showed a decreasing trend. The biomass per unit area and accumulation of N and P were declining exponentially or logarithmically with planting distance. The order of nitrogen removal amount by harvesting aboveground parts was ： C. alternifolius 〉 P. australias 〉 T. dealbata〉 A. donax var. versicolor 〉 T. orientalis, the phosphorus was： C. alternifolius 〉 T. dealbata 〉 P. australias〉 A. donax var. versicolor 〉 T. orientalis. And accumulation efficiency of N and P was P. australias 〉 T. dealbata〉 C. alternifolius 〉 A. donax var. versicolor 〉 T. orientalis. Therefore, plant selection for low-polluted water constructed wetland was not only focused on the high N and P accumulation species, but also would be selected with high accumulation efficiency.