Study On Rapid Planting And Optimal Configuration Of Aquatic Plants Based On Water Purification Of Rivers And Lakes

In recent years,the problem of eutrophication in rivers and lakes in China is outstanding.The use of aquatic plants to purify water is an eco-friendly,green and lasting solution.In view of the slow rate of planting of aquatic plants,the low rate of survival,and the difference in the purification effect of different plant types on pollutants,this research developed a rapid planting technique for aquatic plants that can simultaneously increase planting efficiency and survival rate.And using this technology to plant 5 kinds of common native aquatic plants.Through the optimization of the optimal aquatic plant type configuration and planting density,the class V eutrophic water can be upgraded to class III water.Developed a portable device of planting submerged plant,it not only for shallow water planting,but also for deep water planting.The planting efficiency is doubled compared with the traditional manual planting method,and the survival rate is increased by about 6%.It achieved rapid planting of aquatic plants.The results of plant configuration purification of water results showed,the composite type configuration of the emergent plants and submerged plants is better than the single submerged plant configuration for water purification.The best configuration for the purification of DO,TP,NH3-N and CODcr in water is the composite aquatic plant configuration type of Iris sibirica+Ceratophyllum demersum.The water quality indexes of purified DO,TP.NH3-N and CODcr were maintained at 10.24 mg/L,0.045 mg/L.0.272 mg/L and 13.56 mg/L.respectively.The concentration of DO was increased by 80.98%.The removal rates of TP,NH3-N and CODcr reached 90.00%,83.00%and 74.44%,respectively.The best plant configuration for TN removal in water is the composite aquatic plant type configuration of Iris sibirica+Hydrill a verticillat a.The TN concentration was maintained at 0.83 mg/L and the removal rate was 76.19%.There was no significant difference in the pH of each aquatic plant type in the water test period,and it was always maintained in the range of neutral and weakly alkaline.The results of planting density of aquatic plants showed,In the case of a plant with a height of about 70 cm and a diameter of about 3 cm,the plant height of the submerged plant is about 20 cm and the diameter is about 0.5 cm.The best planting density for the purification of water quality indicators is(50 submerged plants+25 plants)·m-2 for composite type configuration of emergent plants and submerged plants.The best planting density for the purification of each phase index is 75 plants·m-2 for single submerged plant type configuration.The results of nitrogen and phosphorus absorption in sediments by aquatic plants showed,different aquatic plant types have different effects on the absorption of TN and TP in the sediment.Composite plant type configuration is better than single submerged plant type configuration.Within the planting density range of this research,the better absorption effect of aquatic plants on N and P nutrients in the sediment because of the higher the planting density.