Study On Screening And Configuration Of Riparian Buffer Zone Plants In Cities With Highly Efficient Removal Of Pollutants

Urban inland water is an important component of urban water environment,and plays a vital role in maintaining urban development.For a long time,people often pay attention to the economic development,neglect the protection of water resources,and make a large number of water resources polluted and wasted.Pollution of inland rivers seriously endangers people’s production and life.At present,how to repair the polluted river ecosystem has become an international problem,and has become a hot spot for many experts and scholars to study and discuss.In recent years,more and more attention has been paid to the remediation of non-point source pollution by means of riparian buffer zone,which has a good removal effect on non-point source pollution.China’s study on multi buffer concentration effect on the purification effect and prevention of buffer width and slope of non-point source pollution in the buffer zone configuration optimization,selection and configuration of vegetation research is not deep enough,and do the research mainly concentrated in the south to the north of the aquatic plants,plants and land plants less.This study is divided into two parts,one part is the study of hydroponic herb of alfalfa,ryegrass and bluegrass on ammonia nitrogen,soluble phosphate and COD,heavy metals in surface runoff(Cu,Cd,Pb)the removal effect of different buffer zone;plant configuration of another part of the use of laboratory experimental device,through artificial simulation of surface runoff,bluegrass,ryegrass and alfalfa in different vegetation patterns of riparian buffer size of ammonia,water and seepage water nitrite nitrogen,soluble phosphate and heavy metals(Cu,COD,Cd,Pb)study the purification effect.The experiment draws the following conclusions:(1)the removal effects of different herbaceous plants on ammonia nitrogen,soluble phosphate and COD were different.The total removal efficiency of alfalfa was the best,and the average removal rate was 45.93%.The total average removal efficiency of soluble phosphate and COD in ryegrass was the best,and the average removal rate was 54.02%and 56.52%respectively.(2)the removal effects of heavy metals Cu,Cd and Pb in different herbs were different.The capacity of Cu removal of pollutants or as follows:bluegrass>ryegrass>alfalfa;pollutant removal ability on Cd strength as follows:ryegrass>alfalfa>bluegrass;pollutant removal ability on Pb intensity were alfalfa>ryegrass>bluegrass.The removal ability of heavy metals was different under different concentrations.The higher the concentration of Cu and 3 species of herbaceous plants on Cu removal rate is higher,the lower the concentration,the removal rate is relatively low;the higher the concentration of Cd and 3 species of herbaceous plants on the Cd removal rate of pollutants is low,the concentration of Cd is low,the removal rate is relatively low;the concentration of Pb is low.3 kinds of herbs on Pb removal rate is high,the concentration of Pb is low,the removal rate is relatively low.(3)the different vegetation disposition of the buffer zone for nitrogen and phosphorus removal,COD in runoff,and the three hunzai removal rate is generally higher than two hunzai buffer;buffer with different vegetation patterns on nitrogen and phosphorus removal effect,the COD flow is different,three kinds of mixed planting the removal rate is generally high and two kinds of mixed planting vegetation patterns with buffer;buffer zone for nitrogen and phosphorus removal,COD in runoff increased with the sink distance,which means that with the removal of the buffer by buffer width effect.(4)three kinds of mixed planting riparian buffer strips on runoff heavy metal removal efficiency of Cu increased with the increase of water seepage in the distance,the removal rate of Cu is generally higher than the removal rate of 1.5m runoff is low,this is due to copper ions dissolved in the soil was leached out into the flow,and from in the concentration of Cu increased in the three kinds of seepage;hunzai riparian buffer strips on runoff heavy metal removal efficiency of Cd increased with the increase of water seepage in the distance,the removal rate of Cd is generally higher thanThe removal rate of 1.5 m runoff is low;the removal rate of heavy metal Pb in runoff of three kinds of mixed riparian buffer strips increases with the increase of water tank distance;the removal rate of Pb in seepage is generally higher than that in 1.5 m runoff.