Nitrogen Pollution Investigation And Study On Water Purification Technology In The Upper Fuzhou River

The safety of water environment is very important.The river is an important part of ensuring the safety of the water environment.We must strengthen the monitoring and protection of the river's water environment.The Fuzhou River is an important source to alleviate the contradiction between supply and demand of water resources in Wafangdian City and other places in Dalian.However,in recent years,with the rapid growth of population,industrial and agricultural scale of the river basin,point and non-point sources of sewage have also been continuously discharged into rivers.The eutrophication problem caused by the excessive nitrogen and phosphorus nutrient elements has seriously affected the water supply quality and the water environment safety in the upper Fuzhou River.Further investigation and research are urgently needed.Constructed wetland technology is increasingly used in wastewater purification treatment because of its unique advantages of high efficiency,economy,controllability,and ecology.Therefore,on the basis of investigating and analyzing the water pollution status of the upper Fuzhou River,we can design the constructed wetland to ecologically treat the upstream polluted river water to provide assistance for the green and sustainable development of the upper Fuzhou River.First of all,on the basis of understanding the general conditions of the upper Fuzhou River,we went to the upper reaches of the river to conduct on-site investigations of river pollution sources from July to October 2017.At the same time,we set up seven water quality monitoring sections in the upper river to carry out on-site investigations of the river water quality(especially nitrogen)pollution.Secondly,descriptive statistical analysis,correlation analysis,and nitrogen component content analysis were performed on the water quality data surveyed.We finally think that nitrate nitrogen is the main form of total nitrogen in the upper Fuzhou River.The total nitrogen content exceeds the surface water type V water standard,which is mainly from the surrounding agricultural non-point source pollution.Then,this paper introduces the project overview of the pilot test of the constructed wetland technology of our scientific research team in Fuzhou River,Dalian.The paper also summarizes the research results on the plant growth status,hydraulic load and pollution load,pollutant removal effect,and removal influencing factors of wetland.Finally,based on the research results of Cai Fangshen constructed wetland and the pollution status of the upper Fuzhou River,this paper designs a constructed wetland wastewater treatment system to remove nitrogen and phosphorus in Nietun in the upper of Qidaofang Reservoir.The process flow of the Nietun Constructed Wetland is“trashrack?sedimentation tank?parallel,stepped-down horizontal subsurface flow constructed wetland”.Its designed water volume is 25000m~3/d,the wetland surface area is 37030m~2,and the wetland unit size is23m*23m*1.5m.In order to improve the purification efficiency,various types of plants and substrates are selected in the Nietun constructed wetland,and a variety of flood control,anti-freezing,and anti-clogging measures will be adopted during the design and operation stage.