Study On The Pollutant Loading Capacity Of Wuhan Section Of F River

Water pollution capacity is a key issue in total pollutant control and the management of water environment functional areas,which centrally reflects the accumulation and migration process of organic pollutant in natural water and also embodies the maximum capacity of the water function zone to withstand pollutant under certain conditions.In practice,research on the water pollution capacity is often used to guide relevant departments in managing water pollution and plays an important role in relieving natural water pollution loads.In this paper,based on the theory of the water pollution capacity,Wuhan section of the F River is selected as the object,and Code of Practice for Computation on Allowable Permitted Assimilative Capacity of Water Bodies（GB/T25173-2010）is used as the calculation instruction to estimate the water pollution capacity of Wuhan section of the F River.The tasks and conclusions as follow:（1）By investigating all types of pollution sources in the basin,it was determined that the pollutants in Wuhan section of the F River mainly come from urban domestic sewage.Single-factor evaluation method and mean-valued multi-factor index method were used to evaluate the water quality,and the water pollution status of Wuhan section of the F River was determined.According to the changes in the water quality of the four regular monitoring sections in Wuhan section of the F river in the last five years,the water quality has gradually improved,and the average water quality in the river also changed from inferior V water to IV water.（2）Wuhan section of the F River was divided into seven calculation units,and the midpoint generalization method was used to generalize the sewage outlets.The zero-dimensional to two-dimensional mathematical models of water quality were adopted to calculate the pollution capacity of Wuhan section of the F River.By comparing and analyzing the calculation results,the results obtained from the one-dimensional mathematical model were selected as the water pollution capacity of Wuhan section of the F River.The calculation results show that the water pollution capacity of Wuhan section of the F River:COD reached 13081.9t/a,and NH₃-N reached 1703.0t/a.（3）According to the water pollution capacity of each computing unit,a reduction plan for the sewage outlets was proposed:the sewage outlets between the two conventional monitoring sections of the Daishan Bridge to the Zhujia Estuary needs to reduce COD emissions by 391.3t/a,and the total amount of NH₃-N emissions from the sewage outlets between the two conventional monitoring sections of the Lijiadun to the Daishan Bridges need to reduce by 46.9t/a.