人工湿地系统改善滇池入湖水水质

Improvement of Inflow Water Quality of Dianchi Lake Treated by Constructed Wetlands

在代表性高原湖泊-云南省滇池湖区进水口附近构建人工湿地,考察了不同植物(紫叶美人蕉(Canna indica L.)、水葱(Scirpus tabernaemontanl Gmel.)、水葫芦(Eichornia crassipes(Mart.)Solms.)、水芹菜(Oenanthe ja vania(Bl.)DC.)、菖蒲(Acorus calamus L.)、芦苇(Phragmitas communis Trin.))的表流人工湿地与潜流人工湿地的处理效果,试验水力负荷为12 cm/d,水力停留时间(HRT)为3 d。结果表明:紫叶美人蕉潜流湿地、水葱潜流湿地对TP和TN的去除效果运行稳定,前者对TN、TP的去除率分别为70.60%、88.27%,后者为73.33%、83.87%;水芹菜湿地对TP去除效果波动大,均值为84.35%;菖蒲潜流湿地和芦苇潜流湿地对TN的去除率均值分别为71.73%和74.33%,对TP去除效果波动较大。水葫芦、芦苇湿地处理效果(温度较高的夏、秋季节)优于其余植物类型湿地。随着植物进入休眠期,两类人工湿地对TP、TN的去除效率均降低。各植物两种类型人工湿地对COD均有较好的去除效果,数值均在78%以上,出水浓度低于57 mg/L。

Asurface-flow wetland and a subsurface-flow wetland respectively were constructed at the inflow water entrance of Dianchi Lake in Yunnan Province.Six plants such as Canna indica L.,Scirpus tabernaemontanl Gmel.,Eichornia crassipes（Mart.） Solms.,Oenanthe javania（Bl.） DC.,Acorus calamus L.,Phragmitas communis Trin.were planted in the two constructed wetlands in separated sections on condition that hydraulic loading was 12 cm/d,hydraulic retention time（HRT） was 3 d.The results show that the removal efficiencies of subsurface constructed wetlands on TP and TN with Canna indica L.or Scirpus tabernaemontanl Gmel.are stable.Removal efficiencies of the former on TN and TP are 70.60 % and 88.27 %,respectively.Removal efficiencies of the later on TN and TP are 73.33% and 83.87%,respectively.Removal efficiencies of the constructed wetlands on TP with Oenanthe javania（Bl.） DC is unstable,which are 84.35 % averagely.In terms of the subsurface constructed wetlands with Acorus calamus L.and Phragmitas communis Trin.,the average removal efficiencies of TN are71.73 % and 74.33 %,respectively,and removal efficiencies of TP are unstable.The subsurface wetland of Eichornia crassipes（Mart.） Solms.and Phragmitas communis Trin.on removal of TP and TN in summer or fall are more efficient.The two types of constructed wetlands have good effect on the removal of COD,which are above 78 %,and the effluent concentration of CODCr is less than 57 mg / L.