Study On River Water Environmental Capacity In Yizheng

This paper first did overall field investigation and assessment of the water environment and pollutant resource. There were six water pollution control-units to be explained in detail. Based on it ,the water quality models and the water environment capacity models was selected. The rivers were mainly polluted by organic compound, so we took COD_Mn and COD_Cr as the principle components.The water quality models and the water environment capacity models were established by the rivers flow characteristics.For example, a model of two-dimensional unsteady state was used in Yizheng section of Yangtze River, a model of one-dimensional steady state was used in Yiyang River, and a reservoir river model was used in the other rivers.â‘ A method of two points mensuration was adopted in Yiyang River. It should be figured out the least distance and selected spot position. The degradation coefficient of COD_Mn and COD_Cr was established, which was 0.10d^-1 and 0.28d^-1.The coefficient was also identified with the data of last three years. A method of simulation in constant temperature circumstance was adopted in other rivers. it's titers were mensurated from 1 to 10 days continuously. From them, we got degradation coefficients of COD_Mn and COD_Cr in constant temperature circumstance and modified them to be seasoned with practical, which were:Xupu River 0.12d^-1 and 0.33d^-1,Long River 0.10d^-1 and 0.41d^-1,Yanshan River 0.10d^-1 and 0.41d^-1,Yicheng River 0.12d^-1 and 0.45d^-1.It was also identified and got a sensitivity analysis.â‘¡Based on the degradation coefficients, we can get the rivers'water environmental capacity with different flow(water level) and water concentration probability at level of 10%,25%,50%,75%,90%. It's necessary and important to put mensurateing automatically in practice.â‘¢In this paper, It took 90% of flow(water level) and 50% of water concentration for example. We can get water environmental capacity such as Yizheng section of Yangtze River, sectionâ… andâ…¡of Yiyang River, Xupu River, Long River, Yanshan River and Yicheng River, which were 15190t/a,2926.21t/a,764.78t/a, 532.07t/a,502.15t/a,82.65t/a and 63.52t/a.From the results, we knew that the water environmental capacity in Yizheng was relatively richer as a whole. But, the capacity in different section had different quantity. For example, the residual capacity in Yizheng section of Yangtze River, sectionâ… andâ…¡of Yiyang River and Long River were more richer, they also can be used more than 12402.73t/a,2926.21t/a,726.09t/a and 502.15t/a. While Xupu River and Yanshan River's had a few residual capacity about 345.37t/a and 64.3t/a.It should be controlled the total quantity strictly. At last, There was lack of water environmental capacity in Yicheng River. It was accommodated a large quantity of industry wastewater and living sewage yet. So it must be reduced COD_Cr 1870.7t/a at least.Finally, the result of water environmental capacity and forecast of the development of industry were utilized in this paper to total quantity distribute in industry with discharge coefficient method. It should be reduced from 3.62kg/10,000 Yuan to 1.28kg/10,000 Yuan. And total quantity of distribution would be increased from 1828.02t to 1929.05t, which was increased 5.53%. Ulteriorly, this paper also provided the discharge coefficients about major industries. It can be restraining parameters for total quantity distribute.This Paper,according to the water environment capacity calculating process,selected the models of water quality model and water environment capacity model with reason, and designed the experimentation in order to evaluating parameter of water quality with handily. Based on it, it was calculated the dynamic water environment capacities of Yizheng's rivers, which were used in...