Study On The Purification Of 17 Species Of Ornamental Plants For Eutrophic Water

The experiments of greenhouse static state and the simulation experiment of constructed wetland were conducted to investigate of different ornamental plant’s purification on eutrophic waters,the main results are as follows:1.The experiments of greenhouse static state were conducted to investigate of different ornamental plant’s purification on eutrophic waters in summer,autumn and winter.Through different ornamental plant’s depuration evaluation scores for eutrophic water,it is concluded that summer tested ornamental plants in Iris Linn for eutrophic water purification ability are as follows:Iris pseudacorus>Iris ensata vor.hortensis>Louisiana iris.Iris foetidissima,Iris tectorum and Iris japonica are not suitable as summer eutrophic water purification plant material;The experiments of greenhouse static state were conducted to investigate ten species of ornamental plants,such as Louisiana Iris on growth conditions and removal effect on total nitrogen(TN),total phosphorus(TP)and COD in high and middle eutrophic waters.The results shows that:The water purification capability of different ornamental plants as follows:Caldesia parnassifolia>Calla palustris≧ Canna hybrida>Thalia dealbata.>Pontederia cordata = Louisiana iris>Cyperus alternifolius>Iris lactea var.chinensis>Lythrum salicaria>Acorus calamus;The studies that 5 kinds of evergreen plants removal capacity showed that Louisiana iris is the most suitable as the winter of eutrophic water purification materials,followed by Iris foetidissima and Ophiopogon japonicus,water purification effect are relatively weak,Iris germanica L.and Iris japonica’s water purification effect are weaker.Through the comprehensive evaluation of the eutrophication water purification ability of the ornamental plants in winter,the purification ability of the plants are as follows:Louisiana iris>Iris foetidissim≧ Ophiopogon japonicus>Iris germanica>Iris japonica.2.The experiment of Ornamental plants combination shows that:Compared with the single plant water purification,the purification of the combination of Louisiana iris and Iris pseudacorus L was the best treatment,but has not a significant improvement(P>0.05),and the removal efficiency of TN was increased by 1.5%and 1.7%,TP was increased by 1.3%and 3.9%compared with the single cropping;The rest of the combined purification effect is not obvious,and the combination of Iris pseudacorus and Canna hybrida,Iris pseudacorus and Thalia dealbata.are lower than two kinds of single purification effect of plant.3.The experiments of the simulation experiment of constructed wetland were conducted to investigate of different ornamental plant’s purification on eutrophic waters,the main results are as follows:The TN removal rate of Louisiana iris was 46.0%-67.8%,and the TP removal rate was between 54.3%-67.9%;The TN removal rate of Iris foetidissima was 39.5%-55.9%,and the TP removal rate was between 28.6%-52.5%;The TN removal rate of control was 13.3%and 17.3%,and the TP removal rate was between 11.9%and 37.5%.But Louisiana iris and Iris foetidissima removal efficiency of COD were instability.The removal of COD in constructed wetland was influenced by water temperature,light and other factors.Overall,two wetland plant material performed well and purifying effect is remarkable in artificial wetland,and has great practical value.