Effect Of Organic Pollutant Treatment In Zaohe River Using The Constructed Wetland

In recent years, due to extreme deterioration of the water quality of Weihe River,the circumstances of the contradiction between supply and demand of water resources isbecoming more serious in Weihe River basin. In the numerous tributaries of WeiheRiver, Zaohe River is the most seriously polluted. Control on the pollution of ZaoheRiver is of great significance to improve water environment of Weihe River. In order tocontrol the pollution of Zaohe River,the demonstration project of Zaohe River intoWeihe River started running by the end of2010.There are three basic typies ofconstructed wetland in the demonstration project,include vertical flow(VF) constructedwetland, subsurface flowed constructed wetland (SSF) and free water surfaceconstructed wetland (FWS),Which were combined the four processes of VF-SFconstructed wetland SF-FWS constructed wetland,VF-SF-FWS constructed wetlandand FWS-FWS constructed wetland and adopted continuous operation types.For comfirm the best combined process in this demonstration project,the CODand BOD removal efficiency of different constructed wetlands combined processes arecompared in this thesis.The results show that combined processes of constructedwetlands are able to remove organic matter in Zaohe River efficiently.By contrast,thecombined process of VF-SF constructed wetland has the highest removal rate of COD,the removal rates is65.2±13.5%;the combined process of VF-SF-FWS constructedwetland has the highest removal rate of BOD,the removal rates is91.4±7.8%.The effects of filter media and seasonal change on COD and BOD removal areanalysed in this thesis. The results show that stuffing mix of Slag and Peastone was bestwetland filter media to remove organic matter.But under the condition of continuous water input, stuffing mix of gravel and peastone was best appropriate wetland filtermedia to ensure the long term operation of the wetland.Seasonal change have effects onCOD and BOD,the removal rate of COD and BOD increase gradually with the rise oftemperature and the growth of plants in wetlands.In order to find out the purification rules of organic pollutant in differentconstructed wetlands combined processes, the COD removal in combined process ofVF-SF constructed wetland and the BOD removal in combined process of VF-SF-FWSconstructed wetland are simulated by using the first order model.The ecologicalstructure of constructed wetland is analysed.The results show that constructed wetlandnot only could reduce contaminants in Zaohe River,but slso could improve theecological environment.