滇池捞鱼河湿地公园不同功能单元水质净化效果及稳定性

Purification effect and stability of water quality of different functional units in Laoyuhe Wetland Park of Dianchi Lake

以滇池捞鱼河湿地公园(Laoyuhe Wetland Park,WP_(lyh))为研究对象,分别在其不同功能单元设置监测点,研究湿地试运行期间(2015年4月15日—5月14日)不同功能单元对水体化学需氧量(CODCr)、氨氮(NH4+-N)和总磷(TP)的去除效果,并在湿地进水口与出水口设置监测点,对湿地2015年4月—2017年3月的长期运行效果进行监测和分析。结果表明:WP_(lyh)试运行期间出水口COD_(Cr)、NH_4^+-N与TP浓度相较进水口明显下降,去除率分别为40. 07%、48. 48%和40. 38%,但处理效果仍不稳定。各功能单元中,入湖口表流湿地对CODCr去除效果(10. 36%)最佳,林间浅水湿地前部对NH_4^+-N去除效果(17. 59%)最佳,林间浅水湿地后部对TP去除效果(9. 44%)最佳;林间浅水湿地对污染物的总去除率占WPlyh的53. 15%,是湿地的优势净化功能单元。WP_(lyh)长期运行对COD_(Cr)、NH_4^+-N和TP的月均削减量和去除率均随时间呈下降趋势,尤以运行1 a后下降趋势最为明显。

Taking Laoyuhe Wetland Park( WPlyh) in Dianchi Lake as the research object, sampling points were set up in different functional units of the wetland to analyze the removal effects of CODCr, NH4+-N and TP by different functional units in the testing operating period from April 15 th, 2015 to May 14 th, 2015. Sampling points were also set up at the inlet and outlet of wetlands and the long term operation effects in the period from April, 2015 to March, 2017 were monitored and analyzed. It revealed that during the WPlyhtest run, the CODCr, NH4+-N and TP concentrations in the outlet were significantly lower than those in the inlet, with the removal rates of 40. 07%,48. 48% and 40. 38%, respectively, while the treatment effect was still unstable. Among the functional units, the surface flow wetland at the entrance of the lake had the best removal effect on CODCr with removal rate of 10. 36%,the front part of the inter-forest shallow-water wetland had the best removal effect on NH4+-N with the removal rate of 17. 59%, and the back part of the inter-forest shallow-water wetland had the best removal effect on TP with the removal rate of 9. 44%. It means that the decontamination rate of the inter-forest shallow-water wetland accounted for 53. 15% of WPlyhtotal decontamination rate, which could be regarded as the best purification unit in the wetland parks. WPlyh’s monthly reductions and removal rates for CODCr, NH4+-N, and TP during long term operation and the removal rates of the three characteristic pollutants showed a downward trend with time. Especially after one year of operation, the downward trend was most obvious.