NUTRIENT REMOVAL CAPACITIES OF FOUR SUBMERGED MACROPHYTES IN THE POYANG LAKE BASIN

Submerged macrophytes play an important role in eutrophic water purification. Using four species of commonly submerged macrophytes, Ceratophyllum demersum, Elodea canadensis, Hydrilla verticillata and Vallisneria natans (Lour.) Hara, as research objects, and using the Junshan Lake water quality in the Poyang Lake basin as the standard, purification efficiency levels were analyzed for submerged macrophytes at low temperatures using static simulation experiments. The results showed that these four of submerged macrophyte species could partially purify eutrophic water at low temperatures. The purification efficiencies of the four submerged macrophyte species were ranked in descending order as follows: Elodea canadensis, Hydrilla verticillata, Ceratophyllum demersum, and Vallisneria natans (Lour.) Hara. For Ceratophyllum demersum, Elodea canadensis, Hydrilla verticillata and Vallisneria natans (Lour.) Hara. The maximum total nitrogen (TN) removal rates were 67.84%, 68.70%, 64.38% and 69.13% of Ceratophyllum demersum, Elodea canadensis, Hydrilla verticillata, and Vallisneria natans (Lour.) Hara, respectively; the maximum total phosphorus (TP) removal rates were 36.59%, 58.60%, 47.94% and 43.70%, respectively; the maximum NH4+-N removal rates were 23.86%, 24.69%, 18.47% and 22.93%, respectively; the maximum NO3-N removal rates (percentage) were 46.69%, 41.08%, 34.19% and 36.32%, respectively; the maximum PO4-P removal rates were 24.26%, 27.92%, 22.75% and 12.71%, respectively; and the maximum CODMn removal rates of 35.11%, 45.06%, 46.30% and 42.88%, respectively.