The growth conditions of three kinds of aquatic plant was researched in purification experiments. We analyzed three different concentrations of eutrophic water and three species of aquatic plants, namely Acorus calamus, Typha orientalis and Iris tectorum. Nitrogen and phosphorus removal capacity of eutrophic water were analyzed.

The results showed that Typha orientalis and Iris tectorum could grow normally in three levels of eutrophication water, while the growth of Acorus calamus was affected under the highest concentration. There were significant differences in the removal efficiency of nitrogen and phosphorus in eutrophic water. The total nitrogen removal rates of Iris tectorum were 69%, 88.8% and 69.9% for the three concentration levels, while Acorus calamus showed a 66.5%, 82.2% and 54.2% removal rates. Typha orientalis resulted in 64.1%, 77% and 74.3% removal rates, respectively. Regarding to phosphorus removal rates, Iris tectorum resulted in 70%, 87.7% and 77.5%; Acorus calamus presented 54%, 80% and 55.8%; while Typha orientalis numbers were 44%, 60.5% and 61.6%.

The results showed that those three plants could improve the quality of eutrophic water. Iris tectorum has a strong ability to remove nitrogen and phosphorus, while Typha orientalis presented the worst removal rates, especially in phosphorus.