Nitrogen and phosphorus removal effects of different hydrophyte combinations under simulated eutrophic conditions.

Four species of beautiful aquatic plants, including Hydrocleys nymphoides, Iris pseudacorus, Saururus chinensis and Hydrilla verticillata,were chosen to form nine different aquatic plant combinations. The removal effects of nitrogen and phosphorus from eutrophic water containing the above aquatic plant combinations were examined under the controlled eutrophic conditions. The results showed that, the plants could not only grow well in the eutrophic water but also have the removal effects for total nitrogen (TN) and total phosphorus (TP). The maximum accumulative rates of TN and TP in the plants were 53% and 42%, respectively. The removal contribution rates of TN and TP for monoplant experimental cells were 13.79%-65.00% and 18.64%-59.63%, respectively. The removal contribution rates of TN and TP for polyplant cells were 39.61%-72.59% and 9.72%-59.89%, respectively. The removal ability of monoplant cells on TN was in the descending order of H. verticilla, S. chinensis, I. pseudacorus and H. nymphoides. The removal ability of H. verticillata on TP was the highest, while that of H. nymphoides was the lowest. In polyplant cells, the complicated culture units had higher removal ability. The results show that these plants and their combinations all have good removal effects for TN and TP in the eutrophic water and might be applied widely in the landscape water body of city.