Analysis Of Water Environmental Capacity Of Wuliangsuhai Lake

As the drainage area of the entire Hetao Irrigation District,Wuliangsuhai Lake is gradually being taken seriously with the protection of the natural environment.In the feedback from the Central Environmental Protection Inspectorate on the Inner Mongolia Autonomous Region in 2016,the ecological environment governance of "one lake and two seas" was divided.Among them,General Secretary Xi Jinping often mentioned "one lake and two seas",and the water environmental pollution problem of Wuliangsuhai has received public attention.The self-purification ability of the lake itself restricts the amount of pollutants that can be emitted by humans.The calculation and analysis of the water environment capacity of the lake area has become one of the necessary prerequisites for the current Wuliangsuhai water environment management and treatment.Therefore,studying the degradation of water pollutants in Wuliangsuhai can not only understand the current status of Wuliangsuhai's current water environment,but also find ways to improve the water environmental capacity of Wuliangsuhai.In this paper,the southern lake area of Wuliangsuhai Lake is used as the research area.The outdoor water sample collection and indoor experimental analysis are used to calculate the comprehensive degradation coefficient at each point in the lake area,and the water environment capacity of Wuliangsuhai is calculated based on the completely uniform mixed tank water quality model.And the status quo analysis;the use of drained drainage and drainage water quality,as well as the corresponding period of the export section water quality analysis of its potential correlation.The three most significant indicators of Wuliangsuhai pollutants were selected as the water quality analysis indicators of this study,namely total phosphorus(TP),total nitrogen(TN)and chemical oxygen demand(COD).Water was used for these three water quality indicators.Environmental capacity calculation and various water quality analysis can basically reflect the water quality characteristics of the Lake District as a whole.At the same time,according to the water quality monitoring data of Wuliangsuhai entrance and exit from April 2017 to January 2018 for 9 consecutive months,the time variation law and pollutant characteristics analysis were carried out.The pollutant export concentration was significantly correlated with the flow into the lake.The situation will directly affect the quality of the export section.Based on the flow velocity in the Wuliangsuhai Lake area,the first-order reaction kinetic equation is used to calculate the three pollutants by using the lake differentiation point to calculate the comprehensive degradation coefficient.The flow velocity and flow direction of different observation points in the lake area will affect the comprehensive degradation coefficient.That is,the rate of degradation of pollutants is high,and the region with a relatively fast flow rate will have a corresponding comprehensive degradation coefficient.At the same time,the analysis of the factors affecting the comprehensive degradation coefficient verified that the comprehensive degradation coefficient of pollutants was affected by water temperature,total dissolved solids,dissolved oxygen and pollutant concentration,indicating that the comprehensive degradation coefficient of pollutants in Wuliangsuhai Lake area showed different distribution characteristics.Based on the completely uniform mixed water environment capacity model,the water environment capacity of Wuliangsuhai is calculated in four periods throughout the year.The four periods are ice-sealing period,spring water-replenishing period,non-replenishing period and autumn water-replenishing period.Different hydrological and meteorological conditions in different periods,the water environment capacity will also change with the size of external water supply and the comprehensive degradation coefficient.The water quality,water depth,water temperature and microbial activity will affect the water environment capacity of Wuliangsuhai.The water environment capacity of total phosphorus is less than the ice-sealing period in the spring replenishment period,non-replenishment period and autumn replenishment period,and the pollutant discharge in these three periods should be reduced;the total nitrogen-water environmental capacity value in the ice-sealing period is the smallest,chemistry The water environment capacity of oxygen demand is the smallest during the freezing period and non-replenishing period.Reducing the pollutant discharge during this period can maximize the use of Wuliangsuhai and protect its water environment from damage.