Characteristics of nitrogen and phosphorus discharge of main industrial parks in Chongqing in Three Gorges Reservoir Area

In order to clarify the sewage discharge status of key industrial parks in the Three Gorges Reservoir Area, with Changshou chemical park, Fuling industrial Park and Wanzhou industrial park as the key research objects, a total of 48 water samples were collected and analyzed from the drainage channels of sewage treatment plants, the main sewage outlets, the streams into the reservoir and the mainstream of the Yangtze River. The results showed that the concentrations of $NH^{+}_{4}$-N, TN and TP in the water of the drainage channels of sewage treatment plants were 2.58, 13.91 and 0.43 mg/L, the concentrations of $NH^{+}_{4}$-N, TN and TP in the water of main sewage outlets were 18.88, 29.38 and 4.42 mg/L, the concentrations of $NH^{+}_{4}$-N, TN and TP in the water of the stream into the reservoir were 5.48, 12.89 and 0.78 mg/L, the concentrations of $NH^{+}_{4}$-N, TN and TP in the water of the main stream were 0.32, 5.12 and 0.22 mg/L, respectively. The nitrogen and phosphorus concentrations of the main sewage outlets and the stream into the reservoir were 1.93-59.59 times higher than that of Yangtze River main stream water body, which showed that the nutrient salt input characteristics were remarkable to the water quality of the reservoir area. It was suggested that Chongqing City should plan the construction of industrial parks reasonably, control the discharge of industrial wastewater of different industries strictly, reduce the total amount of pollutants entering the river, and reduce the water environment risk in the reservoir area.