The Research On Purification Effect Of 6 Common Submerged Plants On Eutrophic Water In Hunan Province

Water eutrophication is a global environmental problem.Its chain effect leads to the decline of the primary producer,submerged plants,which accelerates the degradation of the aquatic ecosystem,and the transformation of water into the algal body and the further deterioration of the water quality.The existence of the submerged macrophytes plays an important role in the stability of the eutrophic water,also it is essential to choose the common submerged plants to repair the eutrophic water.In this study,6 species of submerged plants,that are common in Hunan,Myriophyllum verticillatum,Potamogeton crispus,Ceratophyllum demersum,Hydrilla verticillata,Elodea Canadensis,and Vallisneria natans,were used as materials to compare the algae inhibition,decontamination and pollution resistance.Plants were planted in eutrophic water to determine the tolerance physiological enzyme indexes in a week or so:proline and MDA,plant biomass and plant height were measured at the end of the test period,and the indexes of chlorophyll a,TN,TP,COD,NH3-N,PH,SS and DO in water were measured every 7 days.Then the dominant species,such as Myriophyllum verticillatum,Potamogeton crispus,Ceratophyllum demersum and Hydrilla verticillata,were selected to compare the effects of different combinations of Submerged Macrophytes on eutrophic wastewatero The algae inhibition ability,decontamination ability and pollution resistance of the 6 submerged plants were evaluated,which provided the theoretical basis of selecting the pioneer macrophyte by using artificial wetland technology to control eutrophic water.The main research results of this paper are as follows:(1)According to the observation of the studied submerged plants,Chlorophyceae and goldilocks showed a more extinguish algae inhibition ability,Goldfish kelp blackweed have a better combined decontamination ability and Black algae bitter herb have the best ability of pollution resistance and growing adaptation.(2)Chlorophyceae and goldilocks these four submerged plants have a better decontamination effect,pollution resistance,and stabler algae inhibition ability.They have a good application prospect in the technology of situ ecological restoration of sewage.(3)The algae suppression efficiency of the combination test group had a significantly higher result than that of single plant,and the highest inhibition rate for planktonic algae is the combination of Hornwort and black algae.From the result of decontamination,the removal rate of COD,NH3-N,SS and the increment of DO were significantly higher than those of the single plant,while the removal rate of TN and TP was lower than that of the single plant.Comprehensive comparison showed that the combination of submerged macrophytes,Goldfish plus bitter grass had the strongest comprehensive purification capacity for eutrophic wastewater.