Selection Of Wetland Plants Used For Renovation Of Eutrophicated Waters And Comparison Of Matrix In Artificial Wetlands

Water Eutrophication, a global environmental issues referring to social economic development and human healthy living, has always been valued by all countries in the world. At present methods of controlling water eutropication available mainly contain physical, chemical and biological methods. As biological method has many special features, like non-side effect, cheap and easy-operating, it has great practicability and good prospect, receiving extensive attention. Large emergent aquatic plant plays an important part in controlling ertropication; it can not only eliminate the nutrients by absorption, but provide suitable living conditions for microbes and zooplanktons, providing another way of eliminating the nutrients. Based on this theory, Artificial wetland technique, gets very efficient treating effect by combining organisms and man-made facilities.This paper studied six types of common aquatic plants in northeast China:Reed (Phragmites australis), Cattail (Typha orientalis Presl), Polygonaceae (Polygonum lapathifolium Linn.), Blackberry lily(Polygonum lapathifolium Linn.), Yellow fleur-le-dis (Iris pseudoacorus) and Iris (Iris ensata Thunb.). By the Analysis of how well these plants remove TN, TP and NH4+-N and their growth index I inquire into the principle of N,P elimination by aquatic plants. A research on the improvement of water quality by three types of matrix, gravel, cinder and sand, in which reed has been planted, was made as well. After a comprehensive discussion, provide basis for the administration of northern waters.The results show that:1 Six types of aquatic plants have certain effect in removing N and P in water, and they showed abilities of different degrees. Viewing as a whole, the result of removing N and P by Yellow fleur-le-dis, Reed and Cattail are better than the other three types, and Yellow fleur-le-dis is the best.2 The comparison between three kinds of matrix show that the sequence of N removing is sand>gravel>cinder; the sequence of P removing is gravel>cinder>sand. The ability of N/P removing differs greatly, so it is necessary to select suitable matrix in practice.