The Relationship of Different COD Concentration, Sediment Pollutant Content with Hydrodynamic in Black Bloom Water Based on Stepwise Regression Method

Abstract To analyze the relationship of different COD concentration, sediment pollutants with hydrodynamic. Taking a polluted river as the research object, the data of flow velocity, water temperature, COD concentration, sediment OM content, sediment TN content and sediment TP content at nine sampling points were analyzed by stepwise regression and SPSS 25 data analysis software. Construct linear regression model of COD concentration Y, river flow velocity X1, water temperature X2, sediment OM content X3, sediment TN content X4, sediment TP content X5. The regression equation Y=106.172-64.304X4 + 0.065X5 with correlation coefficient R=0.954 and determination coefficient R2=0.91 was obtained by stepwise regression method. The results showed that the concentration of COD in water was correlated with the content of nitrogen and phosphorus in river sediments, and negatively correlated with the content of TN and positively correlated with the content of TP. The model can be used to estimate COD load of water body by analyzing the nitrogen and phosphorus content in river sediments.