Analysis Of Water Environment Characteristics Of Qingshui River And Study On Water Quality Improvement Plan

Qingshui River is located in Datun District,Panjin City.The river flows from east to west and flows through Tianjia Street,Qingshui Town,Xinxing Town and Zhaohuanhe Town.It flows into the Shuangtaizi River and enters the sea.It mainly includes 15.4km of Qingshui River,16.8km of Zhaoquan River and 2.5km of connecting channels of two rivers.The rivers that have been successfully managed at home and abroad are studied and analyzed.The rivers in foreign countries include the Rhine River,the Qingxi River and the Thames River.The domestic rivers include the Funan River,the Qinhuai River and the Suzhou River.Secondly,the sewage outlets along the Qingshui River were investigated.There were 58 sewage outlets and 14 sampling points were arranged near the sewage outlets.The annual water quality of the river was monitored,and the single-factor index method was used to evaluate the water environment quality.In the dry season,the river water pollution was the most serious;the second was the flat water period and the high water period.COD has the highest contribution rate of water pollution,followed by NH3-N and TP.The external pollution mainly includes urban and rural living pollution sources,livestock and poultry breeding pollution sources,agricultural non-point source pollution sources,industrial pollution sources,and aquaculture pollution sources.The rivers entering COD,NH3-N and TP are 2243.lt/a and 201.69t/a respectively.27.48 t/a;endogenous pollution mainly includes pollutant release from river sediments,and the releases of COD,NH3-N and TP are 147.2 t/a,17.33 t/a and 6.28 t/a,respectively.The pollution caused by the Qingshui River is mainly due to the poor water quality of the source head;the pollution source is complex,the pollution is superimposed;the sedimentation of the river channel is serious.The water environment capacity of the Qingshui River system is calculated.The Qingshui River is suitable for the one-dimensional water quality model,and the design flow rate adopts a single 90%guarantee rate monthly average flow rate;due to the freezing characteristics of the northern river in winter,the degradation coefficient is divided into ice-sealing period.And non-ice period;the goal of Qingshui River is surface water V-type water;control factors are COD and NH3-N.Determine the calculation parameters and clarify the dynamic water environment capacity of Qingshui River.Based on the safety considerations,the lower control line of water environment capacity is used,the COD water environment capacity is 1126.81t/a,and the NH3-N water environment capacity is 120.19t/a.The COD of the main pollutants in the Qingshui River needs to be reduced by 1263.49 t/a,and the NH3-N needs to be reduced by 98.83 t/a.According to the water quality status survey and water environment capacity calculation,the water quality improvement plan and preliminary engineering design were formulated,including the tail water deep treatment project,the sediment dredging project,the township sewage treatment plant project,the rural sewage treatment facility and the water body ecological restoration.The water quality improvement project is expected to reduce the COD,NH3-N,and TP reductions of pollutants by 1757.63 t/a,184.22 t/a,and 25.78 t/a,respectively.Using the MIKE HYDRO mathematical model for simulation,the MIKE HYDRO mathematical model can predict the water quality before and after the comprehensive treatment project.The simulation time is 72 h and the time step is 1 h.Verification of water level,water quantity and water quality meets the requirements.The average concentration of COD and NH3-N in the entire channel of Qingshui River decreased from 59.54 mg/L and 3.17 mg/L to 35.22 mg/L and 1.37 mg/L,respectively,and the reduction rates reached 40.85%and 36.61%,respectively;The average COD and NH3-N concentrations in the river channel decreased from 60.91 mg/L and 3.33 mg/L to 37.41 mg/L and 1.48 mg/L,respectively,and the reduction rates reached 38.58%and 39.22%,respectively.If the Qingshui River water quality improvement plan is implemented,each treatment project will play an important role in the reduction of pollutants.The river water quality will gradually improve.According to the simulation analysis,the pollutant concentration will be significantly reduced,and the water quality of the Qingshui River can be eliminated.Classify water bodies and strive to reach class IV water bodies.