Study On The Removal Of Nitrogen, Phosphorus And Heavy Metal In Water By Using Hydrophytes

From the engineering practical application's point of view,and by the exam ples of seven plants like scattail,calamus,reed,juncuseffusus,scirpus tabernaemont ani,Zizania caduciflora,as well as cyperus, the thesis discusses these plants'qui ckly growing and breeding,and discusses their antipollution capacity, so as to p rovide technical approach and theory evidence for common application of engin eering. Meanwhile, purification capacity of these seven plants is evaluated in t he thesis in the area of removal effects of pollutants,collection and absorption of the plants themselves, so as to provide reasonable background for practical application of artificial wet land plants, so as to provide appropriate plant reso urce and scientific evidence.the thesis studies the plants which can collect head y metal like Pb and Cd on basis of base-buds in Qin Huai River, adaptive per formance in polluted water and quick breeding methods The wide application o f reed cattail, natural light, buried underground, biological decomposition of 3 compost using comparative test and analysis of feasibility.The research result sh ows:(1) The research of purification capacity of each different water plants shows that different plants result in different absorption and removal of NP. These seven plants can do very well to remove COD,NH3-N,TP from the polluted water. The elimination of COD is mainly done at the beginning 3 days.(2)For water plants, the study on the accumulation and distribution characters of different organs toward nutrient elements shows:for these seven plants, The difference of P content in root and haulm is not big. The biomass in the leaf is the biggest which is the main organ to accumulate N and P elements. The accumulation of N and P in leaf is much higher than other organs.(3)The other key point of this thesis is adaptive capacity of water plants in polluted water. The study result shows:for most of water plants, the critical level of polluted water is 1/3. But these seven water plants in the thesis, their critical level of polluted water is 1/2.(4) The result shows that Pb,Cd content above and under the earth greatly differs among different plants. Among the tested seven plants except uncuseffusus,the distribution of heavy metal Cd element is consistent, namely the part under the earth> the part on the above of earth. And the content of heavy metal under the earth is 3 to 5 times as the one on the above of earth. The heavy metal are mainly concentrate in the roots and haulms of plants. scirpus tabernaemontani, calamus and uncuseffusus are very capable to collect Cd and are greatly potential for purification. Calamus and reeds in water on Pb accumulation effect was significantly higher than that of other plants.(5)The wetland plants composting experimental analysis of wetland plants, three kinds of composting method, biological decomposition method is the most effective, followed by the underground buried method, finally as natural solarization method.