Purification of Eutrophic Water by Native Aquatic Plants

Abstract:

In order to understand the purifying effect of native aquatic plants on eutrophic water, five representative native aquatic plants in Guangdong Province were selected with Eichhornia crassipes as a control for studying the removal rate of total nitrogen (TN), total phosphorus (TP), and the growth and absorption ability of six plants in two kinds of eutrophic water were also studied. The results showed that the TN removal rate of 5 native plants in low and high polluted water increased 3.8%-13.3% and 13.2%-17.1% compared with the blank control, while TP removal rate increased 15.2%-22.1% and 11.3%-57.6%, respectively. Eleocharis plantagineiformis was suitable for purifying low nitrogen water, while Polygonum lapathifolium for high nitrogen water. Saururus chinensis was suitable for low phosphorus water, while Trapa komarovii for low nitrogen or high phosphorus water. Ludwigia adscendens was suitable for the two kinds of eutrophic water and had excellent purification effect for high phosphorus water. All 5 native plants could grow vigorously in low and high eutrophic water and the net growth rate of biomass of Ludwigia adscendens reached up to 375.5% and 539.8%, respectively, showing the best, followed by Trapa komarovii. But the control plant Eichhornia crassipes decayed and died under high polluted water, which aggravated water pollution. Ludwigia adscendens and Trapa komarovii had perfect absorption effect on pollutants, and the TP absorption capacity was better than that of other plants (P<0.05). So, it was suggested that all of five native plants could be used as alternative plants for the restoration of eutrophic water in Guangdong, among them Ludwigia adscendens and Trapa komarovii had excellent development potentiality.

Key words:Aquatic plant;Eutrophic water;Nitrogen;Phosphorus;Water purification