| The Three Gorges Project (TGP) on the Yangtze River is the large-scale hydroelectric project, which possess comprehensive utilization purpose and bring about economic, social benefits. But ecological and environmental problems produced by TGP cannot be ignored. These problems include: the change of hydrogeological characteristics in reservoir area of Three Gorges, velocity of Yangtze River mainstream has been slow down and self-purification capacity has been reduced.Yangtze River is one of the most improtant water sources, which directly impacts the safty of drinking water resources. With the official implementation of hygienic standard for domestic water (GB5749-2006), researchers concerened ahout how to solve the problems produced by TCP. In this case, Artifical Floating Wetland has been used to decrease the concentration of organic pollutants like nitrogen and phosphorus, to repaire ecology of water sources.Artifical Floating Wetland is an ecological restoration technology, which relies on assimilation absorption by plants, degradation by miro-organism and efficiency of physical depositon. This technology is developed by morden horticultural science, biological science and water treatment theories, which can be used to strengthen self-purification of ecology.To test purification effect of Artifical Floating Wetland, experimental study has been carried on in water sources area of Banan district, Chongqing. The main content and results are listed as follows:①Aquantic plants are important factor to determine purification effect. According to the quality of raw water and the principle of choosing aquantic plants, AHP-mutilevel fuzzy model has been built up. This modle is depended on multiple fuzzy theory and weight quantization which has been determined by Analytic Hierarchy Process. Finally, Acorus gramineus, Cyperus alternifolius and Canna indica has been chosen to breed on Artificial Floating Wetland.②According to plant's characteristics and economic benefits, three kinds plants was divided into two independent groups. Group one was designed to breed Acorus gramineus only, group two was designed to grow Canna indica and Cyperus alternifolius together. When hydraulic loading was about 0.33m3 m-2 d-1 and plants area coverage rate was 40%, the resluts show that the average remove rate of TN,NH3-N, TP,CODMn in group one is 26.1%,27.9%,30.1%,25.6% respectively. On the same condition, average remove rate of TN,NH3-N,TP,CODMn in group two is 27.1%,30.8%,32.7%,26.1% respectively.③At the second stage of experiment, group one and group two were combined as series system. The whole artificial floating system was operated in serie to test the remove effect. Under the conditon that hydraulic loading was about 0.25m3 m-2 d-1 and plants area coverage rate was 40%, average remove rate of TN,NH3-N,TP,CODMn is 31.2%,34.1%,32.9% respectively.④According to static test, the relationship among the purification effect, hydraulic retention time, and plant's coverage rate had been researched. Temperature and concentration of organic pollutant are dual-factors, which influent the purification effects.⑤Based on machnism of Artificial Floating Wetland and the analysis of test results, one-level dynamic degredation model of TN,TP,CODMn has been built respectively. The model can be used to predict the effluent quality. Ecology dynamic model of nitrogen has been built as well.⑥Results show that, Artificial Floating Wetland can effectively remove the pollutants of water and bring about social and comprehensive benefits in some extent.
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