Studies On The Purification Ability Of Aquatic Plants Of The Eutrophication Water

The experiment was taken on the basis of resource surveys to the wild aquatic plants in the northeast regions and Hosta ventricosa, Monochoria vaginalis, Alisma orientale, Polygonum orientale and Polygonum hydropiper were choosen for experiment. The paper analyzed the relationship between these aquatic plants and their purification capacity to eutrophication water, and discussed the relationship between the purification capacity and chlorophyll content and root system vitality. Through research and experiment, the results were summarized as follows:1. Hosta ventricosa, Monochoria vaginalis, Alisma orientale, Polygonum orientale and Polygonum hydropiper all had distinct purification to eutrophication water. TN concentrations had varying degrees decline in the treatment waters after planting five aquatic plants in eutrophication water. The decline trends of TN concentrations were essentially same. It declined rapidly in early three days, and became relatively stable after three days. TN concentrations declined faster in the group of 1.500mg/L treatment than in 1.000mg/L one.2. TP concentration for 0.516mg/L declined rapidly in early five days, then declined relatively stable after five days. TP concentration declined rapidly in early three days and was close to the lowest concentration in the 5 day in the treatments of Monochoria vaginalis, Alisma orientale, Polygonum orientale and Polygonum hydropiper when the TP concentration was 0.0516mg/L. It was the same trends in the treatments of Hosta ventricosa, Monochoria vaginalis, Polygonum orientale and Polygonum hydropiper when the TP concentration was 0.0103mg/L. TP concentration declined more visible in the group of 0.516mg/L treatment than the group of 0.0516mg/L and 0.0103mg/L one.3. TN removal rates of five aquatic plants increased gradually with time. The higher TN concentrations and higher of TN removal rates. The TN removal rate of Polygonum hydropipert was the highest of five aquatic plants amounting 86.88% in the group of 1.5000 mg/L treatment in early three days. And it was Hosta ventricosa amounting 82.27% in the group of 1.0000 mg/L one. TN removal rates of five aquatic plants were more than 90% in any concentration treatments in the 15th. Taken together, Hosta ventricosa and Polygonum hydropiper had good purification effect in early three days, and Hosta ventricosa, Alisma orientale, Polygonum orientale and Polygonum hydropiper all had good purification effect in the 15th.4. TP removal rates of five aquatic plants increased gradually with time. TP removal rate of the group of 0.516mg/L treatment was higher than the groups of 0.0103mg/L and 0.0516mg/L one. TP removal rate of the group of 0.5160mg/L treatment was more than 90% inearly three days, And Hosta ventricosa, Alisma orient ale and Polygonum hydropiper had good performance. TP removal rate of the group of 0.0516mg/L treatment was more than 80% in early three days. And TP removal rates of Alisma orientale, Polygonum orientate and Polygonum hydropiper were more than 60% in the group of 0.0103mg/L treatment in early three days.5. The trends of chlorophyll content changes were essentially same in every TN concentration treatment. First it rised rapid and then declined slightly and then smooth recoveried. The chlorophyll content of Hosta ventricosa which TN removal rate of was high was highest, followed by Alisma orientale, followed by Polygonum orientale and Polygonum hydropiper, finally followed by Monochoria vaginalis. The chlorophyll content changes of different aquatic plants were different in different TP concentration treatments. The chlorophyll content changes of five aquatic plants consistented performance in the TP concentration treatments of 0.0516mg/L and 0.0103mg/L. The chlorophyll contents of Hosta ventricosa and Monochoria vaginalis changed steadily and decreased slightly with time. The chlorophyll contents of Alisma orientale, Polygonum orientale and Polygonum hydropiper rised in early three days and decreased slightly in the 5th day then rised slowly.6. The percentage changes of the active absorb area of root system vitality of five aquatic plants were not significant.7. Hosta ventricosa grew best in all concentration treatments among five aquatic plants. It flowed by Polygonum hydropiper and Polygonum orientale. The leaves of Alisma orientale were withered because of high evaporation. Monochoria vaginalis grew better in early five days but not strong after ten days.8. Aquatic plants were not only purified water but also had good landscape effect, and it could be used in the urban landscape water. Five aquatic plants could be used restoration plants to treat eutrophication water in urban landscape water, because they had not only good landscape effect but also purification effect. Especially, the flowers and leaves of Hosta ventricosa, Polygonum orientale and Alisma orientale all had ornamental value, and they were not strict on the environment besides of good adaptability and economic value, As long as meet their ecological habits to good landscape effect.