Water Purification Effect Of Aquatic Plants Communities In Constructed Wetland Parks

At present,China's water resources are scarce.Constructed wetland parks took an important role urban water system conservation and water purification.Among the existing methods for purifying eutrophic water bodies in artificial wetland parks,the use of plant absorption was the most widely used,quicker and less investment.The existing artificial wetland parks faced the main problems when purifying eutrophic water bodies: herbaceous emergent plants grow slowly in winter and the water purification effect declines;artificial wetland parks had good water purification effects in the early stage and lack of strength in the middle and late stages.The circulation pollution caused by the deciduous,withered and dead of herbaceous anhydrous plants when they proliferated in wetland parks.Existing scientific research data mainly focued on the water purification capacity of single plants,and lack of the overall water purification effects on plant communities.In this paper,it took the typical artificial wetland park,Tianhe Guangzhou city wetland park as the research object.By conducting plant community surveys and water quality monitoring and analysis in this park,we conducted simulation experiments on the water purification effects of aquatic plant communities to improve plant communities.Expected results of the water purification effects of the plant community.Finally,the excellent plant community selected by the simulation experiment was planted in Tianhe Wetland Park,and the water purification effects monitoring experiment of the plant community under the condition of dynamic flowing wate.The research results were as follows:(1)The tianhe wetland park water quality status: In the test of 13 sampling points of Tianhe Wetland Park in April 2019 to January 2020 of a period of 10 months,63.8% of the values based on the comprehensive factor water quality index were Category V and inferior.Category V water quality.TN and TP were the two most serious indicators of exceeding the standard.The existing plant communities couldn't achieve the expected water purification effects.Many physical and chemical indicators of Tianhe Wetland Par began to deteriorate,including: total nitrogen,total phosphorus,ammonia nitrogen and turbidity when it was after the Octorber.Among the 13 sampling points,sampling point No.7,sampling point No.9,sampling point No.9,and sampling point No.10 were multiple points of deterioration of the water quality of the month.The status of plant communities needed to be improved.(2)Different plant communities showed different purification capabilities for the same eutrophic water body.Purification effects of composite aquatic plant communities oneutrophic waters.In the experiment: 12 groups of experiments were configuredAmong them: the best among the arboreal plant communities was T4,which was better than T3;the best among the plant communities that change the emergent plants was T7,which was better than T3;the best among the plant communities that change submerged plants There were 7 items for T10 that are better than T3.(3)The plant community needs to be planted in the actual site to provide services for the artificial wetland park.Select the plant community with better water purification ability in Chapter 3(Callistemon viminalis + Bischofia javanica + Canna indica + Juncus effusus +Vallisneria natans + Hydrilla verticillata).The sampling point No.7 with poor water quality during the survey in Chapter 2(T1 group)No.8 sampling point(T2 group),No.9sampling point(T3 group)and No.10 sampling point(T4 group).Study on the purification effects of aquatic plant communities in the artificial wetland dynamic water flow experiment: he water in experimental zone and controlled zone wer from the same water entry,where the named“ A” was the community composed of plants selected in Chapter 3 and “B” was the original plant community was maintained in the control area.There was no data due to the extremely small amount of water in the T4 group in Guangzhou during the winter when precipitation decreases.In terms of total phosphorus and total nitrogen,the composite aquatic plant community performed very well.The composite aquatic plant community showed significantly better effects on total nitrogen in the water body than the native plant community,but the effects of the ammonia nitrogen pair was only a slight advantage.The complex aquatic plant community also showed a good removal rate of COD.T2 A and T3 A showed a COD removal rate of more than 20%,and T1 A was also higher than T1 B.In the turbidity removal rate,the experimental group of T1 A and T2 A can achieve an effect of more than 30%.During the three-month monitoring,according to the analysis of seven indicators between the experimental area and the control area,it can be concluded that the water purification effects of the composite aquatic plant community was better than the original community.(4)In summary,It can be better enhancing the water purification effects by adjusting the existing plant communities in Tianhe Wetland Park.It proved that the purification effect of "woody + herbaceous water + submerged water" plant communities was better than that of "herbaceous water + submerged water" communities through experiments..Therefore,suggestions for improving the water quality of Guangzhou Artificial Wetland Park were asfollows: firstly ensure the water quality of the water inlet,and the targeted growth of submerged plants and other aquatic plants with fast growth rate which was convenient for cutting.And then,some wetland woody plants were planted in the dense area to reduce the cycle pollution caused by the growth of aquatic plants.Secondly,it is necessary to build a reasonable aquatic plant community to restore the plural,multi-layer and diverse ecosystems of wetlands,and to promote the purification effects of artificial wetland parks through the improvement of wetland ecosystems.Finally,improving the management and maintenance methods of artificial wetland.From traditional manual to intelligent way,plants are mowed and salvaged in time to reduce the cyclic pollution of plants withering into the water.Sensors are used to monitor water quality and establish an early warning system.