人工浮岛在上海白莲泾河道水质治理中的作用

2007年9月~2008年3月,为改善上海白莲泾世博园区段的水质,在该河段构筑了一段由鱼类、贝类和植物组合的人工浮岛,并对浮岛内外水质进行了跟踪监测。结果显示,人工浮岛显著提高了水体溶解氧(DO),降低了悬浮物(SS)含量,提高了水体透明度,同时显著降低了总氮(TN)、氨氮(NH3-N)、总磷(TP)、活性磷(PO4--P)。人工浮岛构筑初期(2007年9~10月),整个生态系统尚处于适应阶段,浮岛内外水质并无明显差别,DO总体均低于5mg/L、SS均大于40mg/L、TN含量均高于2.0mg/L、NH3-N含量均高于1.0mg/L、TP含量均高于0.15mg/L、PO4--P含量均高于0.05mg/L,此时浮岛对河道水质的改善效果不佳;2007年11月至08年2月,由菖蒲、鲢鳙鱼、三角帆蚌组合的浮岛生态系统结构稳定,各类生物生长状况良好,对水质有明显的改善效果,浮岛内水体DO含量提高至8.0mg/L以上、SS含量降低至10mg/L以下、TN含量较浮岛外均降低了2.0mg/L、NH3-N含量较浮岛外降低了3.0mg/L、TP含量总体均降低至0.06mg/L、PO4--P含量降低至0.03mg/L;构筑后期(2008年3月),浮岛缺乏必要的人工维护和管理,冬季植物死亡、腐烂,再次释放出N、P等营养物质进入水体,使得人工浮岛处理效果明显降低,造成二次污染,浮岛内水体中各指标含量迅速上升至处理前水平。

Building Artificial Floating-island for Treating Bailianjing River in Shanghai

An artificial floating-island composed of fish,shellfish and aquatic plants was designed for bioremediation in Bailianjing River,Shanghai.From September 2007 to March 2008,water samples were collected respectively twice a month and DO,SS,TN,NH3-N,NO3-N,NO2-N,TP and PO4--P were analyzed to test system efficiency.Results showed that artificial floating-island can not only increase DO obviously,reduce SS,enhance transmittance of water body,but also remove nutritious substance in water body dramatically.In early stage of artificial floating-island constructed from September to October 2007,efflux of the system was not steady,and results showed that DO in general was lower than 5mg/L,while SS,TN,NH3-N,TP and PO4--P exceeded 40mg/L,2.0mg/L,1.0mg/L,0.15mg/L and 0.05mg/L respectively.In the middle period of research from Nov.2007 to Feb.2008,whole ecosystem composed of Acorus calamus Linn,Hypophthalmichthys molitrex,Aristichthys nobilis and Hyriopsis cumingii was steady,and all kinds of organisms in floating island were in good condition,resulting in the improvement of water quality.Results showed that DO inside the floating island increased to 8.0mg/L or above,SS was reduced to 10mg/L,TN and NH3-N was 2.0mg/L and 3.0mg/L lower than the outside,while TP was generally reduced to 0.06mg/L and PO4--P decreased to 0.03mg/L.During the latter stage of the study in March,2008,because of lacking of necessary maintenance and management,growth of hydrophytes was restrained,the treatment effect of artificial floating island was significantly reduced,and resulting in secondary pollution and deteriorate water quality.