Purification Effect of Various Submerged Macrophyte Combinations on Eutrophic Water

Four common macrophytes including Vallisneria denseserrulata, Ceratophyllum demersum, Hydrilla verticillata and Elodea canadensis in Zhejiang province were selected for experiment during May 22nd and June 26th, 2019.They were treated for eleven combinations for purification test in simulated eutrophic water in lab.The results showed that the submerged plants grew normally in eutrophic water, and different combinations had obvious effect on the removal of pollutants in water.The combination of V.denseserrulata + C.demersum + H.verticillata + E.canadensis had the best growth, and the final increase in biomass was 3.89 g.Combinations of V.denseserrulata + C.demersum + E.Canadensis and V.denseserrulata + C.demersum + H.verticillata + E.Canadensis had the best purification effect on total nitrogen and total phosphorus with removal rate of 86.14%, 83.52% and 85.59%, 81.26%.The removal rate of NH4 +-N by each combination was more than70%.Among them, the combinations of V. denseserrulata + C.demersum + H.verticillata + E.canadensis and V.denseserrulata + C.demersum + H.verticillata had the best purification effect, the removal rates were 97.78% and 96.89%.The best combination of CODMn removal was the combinations of V.denseserrulata + C.demersum + H. verticillata + E.canadensis and V.denseserrulata + C.demersum + E.canadensis, with the removal rate of 89.63% and 88.96%.Comprehensive analysis demonstrated that the combinations V.denseserrulata + C.demersum + E.canadensis and V.denseserrulata + C.demersum + H.verticillata + E.canadensis had 9 points of removability, indicating the optimal plant combination for purification of eutrophic water.