Purification Effect Of Submerged Plants On Eutrophic Water

The captive submerged plants will plant the domesticated submerged plants in the ecological flexible modular management device,using submerged plants to purify water and the relative portability of modular management of devices.In the artificial wetland project,the whole module is used to transport,plant and clean the submerged plants.In this study,we selected the common submerged plants in Anhui,for example Vallisneria natans?Lour.?Har?Myriophyllum verticillatum L.?Ceratophyllum demersum L.?Hydrilla verticillata?Linn.f.?Royle?Elodea canadensis Michx.and Herb of Distinct Pondweed.Taking the eutrophication water of cyanobacteria as the dominant population as the control object,a series of single factor experiments were designed to study the pollution tolerance,pollutant removal and phytoplankton inhibition of single submerged plants.?1?Three dominant submerged plants were selected,namely,Vallisneria natans?Lour.?Har?Myriophyllum verticillatum L.?Ceratophyllum demersum L.On the 21st day of the experiment,the biomass of three submerged plants increased by 85.2 g?91g?64.2 g,The plant height increased by 4.6 cm?5.7 cm?16.7 cm.The removal rate of COD by these three submerged plants is between 43.21%and 46.59%,SS removal rate is between 74.36%and 80.49%.The removal rates of NH₃-N,TN,SS and TP are73.67%?76.69%,70.51%?74.39%,80.49%?74.36%,50.85%?61.55%,respectively.Do increased by 70.09%?78.55%,the inhibition rate of phytoplankton is 56.25%?64.71%.?2?The combination of these three submerged plants was planted,and the pollutant removal ability and phytoplankton inhibition ability of the submerged plants combination were compared.Finally,the combination Vallisneria natans?Lour.?Har+Ceratophyllum demersum L.was selected.During the experiment,the removal rate of COD,SS,NH₃-N,TN,TP and phytoplankton was 46.34%,81.4%,77.39%,69.94%,64.57%and 75%respectively.?3?The dynamic flow wetland model was built,and the hydraulic retention time was set as 4 d.To study the purification effect of Vallisneria natans?Lour.?Har+Ceratophyllum demersum L.on eutrophic water in dynamic flow.At the end of the experiment,the final removal rates of COD,NH₃-N,TN and TP were 33.3%,44.59%,32.9%and 38.55%respectively.Experiments show that in dynamic flow,submerged plants still have a good removal effect on pollutants in water.?4?On the basis of the above experiments,the effects of planting proportion and planting density on the purification of eutrophic water by dominant submerged plants were further studied.It was found that when the planting ratio was 3:2?biomass?and the planting density was 4-5 g/L,the combination of Vallisneria natans?Lour.?Har+Ceratophyllum demersum L.was the best way to remove pollutants in water.Therefore,it can provide the theoretical basis for the selection,planting combination,planting proportion and density of plants in the subsequent use of submerged plants in the treatment of eutrophic water body by Artificial wetland technology.