Research On Water Environment Capacity Accounting And Total Nitrogen Precision Emission Reduction In Xiongyue River Basin

Water environmental pollution is one of the major environmental issues of global concern.Due to the unique environmental characteristics of the estuary and the bay,the ecological and environmental problems are more serious.In the comprehensive treatment of the ocean,land-based pollutants are the main pollution sources.The study area of this paper is located in Yingkou City,Liaoning Province.As a river flowing into the Bohai Sea,Xiong Yue River carries a lot of pollutants.This paper takes the Xiongyue River basin as the research object,according to the concept of "pollutant pollution load verification-water environment capacity calculation-pollutant reduction",to achieve the "fourteenth Five-year" Marine ecological environment protection planning target,and puts forward the total nitrogen precise emission reduction plan in the Xiongyue River basin.According to the investigation,a state-controlled section of Yangjiatun is set on the main stream of Xiongyue River,which is located in Bayuquan district of Yingkou City,and is the sea section of Xiongyue River basin.Because Xiong Yue river water quality target for class,through the yangjiatun section in 2015-2020 water quality data analysis,control the surface water environmental quality standard of surface water 24 basic project standard limits,chemical oxygen demand concentration most overweight,ammonia nitrogen concentration,total phosphorus concentration of individual years,total nitrogen concentration each average,other indicators are not overweight.On this basis,we selected the four pollutants of chemical oxygen demand,ammonia nitrogen,total nitrogen,total nitrogen and total phosphorus as the measurement indicators,and further monitored the Xiong Yue River in 2021 and 2022.According to the monitoring results in 2021 and 2022,the analysis shows that ammonia nitrogen meets the water quality standard at all points;the chemical oxygen demand,total nitrogen and total phosphorus did not meet the water quality standard,including the 28 points,28.6% of the points,the total nitrogen reaches the standard,and 89.3% of the total phosphorus not reached the standard,and the water pollution in the north branch of Xiong Yue River is quite serious.In this study,the pollution load of the main pollution sources in Xiongyue River basin is calculated by output coefficient method and discharge coefficient method,the water environment capacity is calculated by one D water quality model,and the author controls the total nitrogen in the Xiongyue River basin,and the targeted total nitrogen reduction scheme is proposed.This conclude as follows:(1)According to the monitoring data statistics in 2021 and 2022,the chemical oxygen demand,ammonia nitrogen,total nitrogen and total phosphorus in Xiong Yue River,among which the chemical oxygen demand,total nitrogen and total phosphorus all exceeded the standard,and the ammonia nitrogen did not exceed the standard.Among them,the highest chemical oxygen demand is about 0.63 times,the highest total nitrogen is about 50.5 times,and the highest total phosphorus is about 10.35 times.Therefore,it can be judged that the main exceeding factors of Xiong yue River are chemical oxygen demand,total nitrogen and total phosphorus.(2)According to the pollution load accounting of the Xiongyue River Basin,The inflow of chemical oxygen demand of urban domestic sources is 357.74 t/a,Total nitrogen inflow was 34.84 t/a,The total phosphorus inflow is 3.16 t/a;The inflow of chemical oxygen demand from rural domestic sources was 370.95 t/a,Total nitrogen inflow was 18.84 t/a,The total phosphorus inflow is 1.64 t/a;The inflow of chemical oxygen demand from livestock and poultry breeding sources is 315.01 t/a,Total nitrogen inflow was 14.8 t/a,The total phosphorus inflow amount is 4.5 t/a;,The chemical oxygen demand intake is 620.00 t/a,The inflow of total nitrogen was 58.96t/a,Total phosphorus inflow was 4.06 t/a.Therefore,the chemical oxygen demand inflow in the Xiongyue River Basin is1663.7 t / a,with the agricultural planting source being 37% of the chemical oxygen demand inflow,and the secondary urban living source being 22% respectively;and the last livestock and poultry breeding source is 19%.Total nitrogen inflow is 127.44 t / a,including: agricultural planting source,accounting for 46% of the total nitrogen inflow;followed by urban source 27%;then rural source 15%;and livestock and poultry source 12%.Total phosphorus into the river is 13.36 t / a,including livestock and poultry breeding source is the main pollution source,accounting for 34% of the total phosphorus into the river;then agricultural source for 30%;then urban source for 24%;rural source for 12%,there is no industrial enterprises in the study area,so there is no industrial pollution source.(3)According to the calculation results of water environmental capacity of Xiongyue River Basin,the water environmental capacity of 5% safety allowance is2871.73 t/a,and the water environmental capacity of total phosphorus is 0.475 t/a,which is surplus;while the water environmental capacity of total nitrogen is-272.79t/a,which is negative,indicating that the environmental capacity of total nitrogen is free.Therefore,the chemical oxygen demand and total phosphorus need not be reduced,and the total nitrogen needs to be reduced by 272.79 t/a.(4)according to the Xiong Yuehe pollution to determine the target,the diagnosis of environmental problems,put forward a series of pollution reduction measures,and according to the Xiong Yue river basin pollutant reduction analysis results,planning project a total of six,including: three projects for urban pollution projects,two for agricultural non-point source project,1 for livestock and poultry breeding source project.Urban pollution source project,livestock source project and poultry source project and agricultural non-point source project can reduce the total nitrogen by about 282.03 t/a,basically achieving the reduction target of 272.79 t/a.According to the engineering analysis,the reduction of total nitrogen is mainly non-point source reduction,and the total nitrogen reduction of non-point source accounts for more than80% of the total reduction.In addition to the implementation of project treatment,the reduction should also be made through management measures,through the active prevention and control of planting pollution,improving the construction of urban pipe network,promoting the treatment of rural domestic sewage,strict control of livestock and poultry breeding pollution,strengthening the management of river inside and outside,and strengthening supervision.(5)according to the principle of easy first after difficult,take "qing,resistance,lift," comprehensive measures,the recent "qing,resistance",in view of the pollution sources formulate corresponding reduction plan and control countermeasures,and analyze the reduction scheme,make it realized during the period of "difference" sea river section total nitrogen concentration is the goal of negative growth in 2020.