| At present,researches had been conducted on the configuration of artificial wetland plants,the material selection and assembling of matrix,the mechanism of sewage treatment and the type of sewage treatment.The plant is an important part of the constructed wetland system.The growth of plants is affected by the environment,as a result,the distribution is very regional and the combination of different plants matrices will show different treatment effect.Therefore,in different regions,construction of artificial wetlands,not only to consider the effect of plant water purification,but also to consider its suitability.At the same time,different flow patterns and combinations of processes will also affect the wetland system to deal with sewage capacity.In this paper,according to the "water pollution control and management of national water pollution control and management" special project "Yinma River Basin water pollution comprehensive management" needs,through the study of the common wetland plant Phragmites australis?Typha orientalis?Heleocharis equiaetiformis?Scirpus triqueter?Heleocharis dulcis?Butomus umbellatus?Trapa bispinosa?Spirodela polyrrhiza and Ceratophyllum demersum,the use of zeolite?volcanic slag?furnace ash in proportion to the proportion of the composition of the wetland system,to explore the different wetland system water purification efficiency,screening efficient local water purification plants;the use of selected plants and known landscape and water purification effect And the multi-stage artificial wetland simulation system,including the surface flow constructed wetland and the subsurface flow constructed wetland,studied the different technological combinations in the vegetative growth season and the breeding season and pulsed flow respectively.Simulation system for the removal of pollutants.The results of this study can provide a scientific basis for the large-scale construction of constructed wetlands,improve the efficiency of wetland treatment of sewage,improve the quality of regional rivers and the restoration of damaged aquatic ecosystems.The main research results are as follows:(1)The small experiment simulations were carried out to select nine species of wetland plants,Phragmites australis ? Typha orientalis ? Heleocharis equiaetiformis ? Scirpus triqueter?Heleocharis dulcis?Butomus umbellatus?Trapa bispinosa?Spirodela polyrrhiza and Ceratophyllum demersum,In this paper,we studied the common reed,cattail,trough water chestnut,Scirpus,Sagittaria,Iris,Water chestnut,Purple duckweed and Duckweed in the wetland of the Songhuajiang River in the Songhuajiang River through a small wetland simulation experiment.Effects of 9 Species of Wetland Plants and Their Combined on the Purification of Chemical Oxygen Demand(CODcr),Nitrogen and Phosphorus in River Water.The results showed that the selected wetland plants could effectively improve the water quality of the river water under the simulated environmental conditions.The different wetland plants had obvious difference in the purification of pollutants in the wastewater.The Butomus umbellatus shows the best in removing TP,CODcr and NH3-N,the removal rate were 99.65%,68.22% and 99.54%,respectively.The Typha orientalis,Trapa bispinosa and Ceratophyllum demersum show best in removal TN,and the removal rate was 66.19%.The best removal efficiency of NO2-N are Heleocharis equiaetiformis,Phragmites australis and Ceratophyllum demersum,and the removal rate was 83.64%.The effect of comprehensive treatment on various pollutant indicators is generally better than that of individual species.The removal efficiency of various plants and their wetland systems changed regularly with the time.It is the pollutant concentration in the water was decreased rapidly in the first two days,decreased slowly after 5 days,and stabilized after 5 days.(2)During the growth season and the breeding season,the purification experiment was conducted in Yudai River,the branch of Yitong River,based on the Internal circulation+surface flow wetland-second flow.The results showed that the removal of TN,TP,and CODcr by pulsed recirculating artificial wetlands is rapid and efficient,which can reach 82.78%,54.23% and 61.49% respectively.The removal efficiency of the breeding season can reach 83.68%,58.02% and 55.73% respectively,moreover,the concentration of CODcr in the final effluent can be effectively stabilized.The removal effect of traditional subsurface wetland on pollutant index is worse than that of circulating water,but the treatment effect is obvious as well.Sewage through the internal circulation wetland treatment,and then into the surface wetlands,results show the surface wetlands can effectively enhance the dissolved oxygen content in the water,and further stable removal of pollutants in water.The removal rate of surface flow wetland-second flow on TN,TP,and CODcr are 66.17%,83.33% and 68.85%,respectively.The treatment efficiency dring breedling season was 67.38%,80.53% and 85.5%.In the second-stage wetland treatment system,the treatment efficiency of each pollutant was different in the growing and breeding stages.The treatment efficiency of N and P was higher in the breeding period than that of in the growing season,while the treatment efficiency of CODcr was in the opposite way.(3)Through the pulsed flow water supplement,the purification effect experiment of the growing and breeding period's subsurfaceflow+Surfaceflow+Surface flow +subsurfaceflow multi-stage series wetland system towards rivers shows,The experimental results show that in the intermittent influent ranges from 440L/d to 2640L/d,the daily treatment capacit is 2200L/d,the system can achieve large processing efficiency for CODcr,TN,TP and SS as a whole,the efficiency is 71.57%,85.16%,81.77% and 34.6% respectively in growing season,and 73.16%,73.91%,78.36% and 48.2%,respectively in breeding season.In the subsurface flow + surface flow + surface flow + subsurface flow wetland system,the growth period and the breeding period of the pollutant treatment effect is also different.The treatment efficiency of TN and TP was higher in breeding season than that of in growing season,but the treatment efficiency of CODcr and SS was in the opposite way. |
PDF Full Text Request