A Study Of Effects Of Five Wetland Plants On Removing TN,TP,Pb And Cd From Brackish Water

Constructed wetland is a kind of ground similar to marshland constructed and controlled artificially,as well as a kind of technology of treating sewage and sludge by triple synergism of physics,chemistry and biology of soil,artificial medium,plant and microorganism.So it has been widely applied to purify water bodies.Constructed wetlands have been widely used to treat industrial sewage and domestic sewage at home and abroad.However,in the context of high salinity and alkalinity,the constructed wetland sewage resource treatment system with high performance is very rare in Xinjiang.In 2019,the author made an experiment of simulating constructed wetlands,studied the effects of several wetland plants on removing TN,TP,Cd and Pb from brackish water,and explored the cultivation mode of the plants in constructed wetlands to provide theoretical basis and technical support for the technology of pollutant removal of constructed wetlands in brackish water lake in arid areaThis paper studies the effects of scirpus Scirpus validus Vahl and Typha orientalis Presl on removing TN,TP,Pb and Cd from brackish water by planting them in simulated constructed wetland.Removal rates have been calculated since 1 April,In 30-day cycles.It can be seen from the comparison with the influent concentration(the removal rate)that scirpus Scirpus validus Vahl wetland,Typha orientalis Presl wetland and CK wetland without plant cultivation can better remove TN,TP,Pb and Cd.From the perspective of the highest removal rate,the removal rate of TN and TP is respectively 95.3%and 85.3%in the period of Second Cycle(30d～60d)for scirpus Scirpus validus Vahl wetland,and the removal rate of Pb and Cd is respectively 97.7%and 52.7%in the period of First Cycle(1d～30d)for Typha orientalis Presl wetland.It can be seen from the comparison with CK wetland without plant cultivation(the removal rate 2)that for scirpus Scirpus validus Vahl,the removal rate of TN is 66.7%in the period of First Cycle(1d-30d),and that of TP is 60.7%in the period of Second Cycle(30d-60d));for Typha orientalis Presl,the removal rate of Pb is 65.0%in the period of First Cycle(1d～30d),and that of Cd is 52.7%.This paper studies the effects of reed,Phragmites communis Cyperus rotundus and epilobium parviflorum on removing TN,TP,Pb and Cd from brackish water by planting them in simulated constructed wetland.Removal rates have been calculated since July 1,In 20-day cycles.It can be seen from the comparison with the influent concentration(the removal rate 1)that the three wetlands significantly better remove TN,TP,Pb and Cd compared than CK wetland without plant cultivation.From the perspective of the highest removal rate,for reed wetland,the removal rate of TN is 91.4%in the period of First Cycle(1d～20d),the removal rate of TP is 91.5%in the period of Third Cycle(40d～60d),and the removal rate of Pb is 83.9%;for epilobium parviflorum wetland,the removal rate of Cd is 76.6%in the period of First Cycle(1d～20d).It can be seen from the comparison with CK wetland without plant cultivation(the removal rate 2)that for Phragmites communis Cyperus rotundus,the removal rate of TN is 67.4%in the period of Third Cycle(40d-60d);for reed,the removal rate of TP is 78.3%;for Phragmites communis,the removal rate of Pb is 62.7%in the period of Third Cycle(40d～60d);for epilobium parviflorum,the removal rate of Cd is 55.3%in the period of First Cycle(1d～20d).This paper studies the effect of Typha orientalis Presl on removing TN,TP,Pb and Cd from brackish water based on the L16 45 orthogonal test.Removal rates have been calculated since July 11,In 20-day cycles.For Typha orientalis Presl,the removal rate of TN was 58.2%98.4%.The most significant effect on the removal rate of TN is degree of mineralization,negatively correlated.That is to say,with the increase of degree of mineralization,for Typha orientalis Presl,the removal rate of TN decreases,and the removal rate of TP range from 37.3%to 93.1%.The most significant effect on the removal rate of TP is Cd,negatively correlated.The removal rate of Pb is 59.2%～98.7%;The most significant effect on the removal rate of Pb is TP,positively correlated.The degree of mineralization is negatively correlated with the removal rate of Pb;the removal rate of Cd is 8.4%～98.5%.In the 3(40d～60d)and 4(60d～80d)cycles,all factors were negatively correlated with Cd removal rate.The factors influencing Typha orientalis Presl plant height are:TN>TP>Pb>M>Cd.In addition to degree of mineralization,all factors are positively correlated with the increment of plant height;the factors influencing the number of Typha orientalis Presl plants:M>TP>TN>Cd>Pb;when the degree of mineralization is at a low level and TN and TP are at a high level,Typha orientalis Presl can better grow and branch.