Hunan Wastewater Treatment Plant, Xupu County, Hunan Province, China

The Hunan wastewater treatment plant is located in Xupu County, Huaihua City, Hunan Province, China. It serves a population equivalent of 105,000, classifying it as a medium-to-large agglomeration under Chinese wastewater management standards. The plant is situated along Xushui South Road, near the Xushui River, a tributary of the Yuan River system. As a facility serving over 100,000 people, it is expected to comply with China's Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), which mandates secondary treatment with nutrient removal for plants of this scale. Typical Chinese plants of this size employ activated sludge processes with biological nitrogen and phosphorus removal to meet Class 1A or 1B effluent standards. The treated wastewater is discharged into the Xushui River, which flows into the Yuan River, a major tributary of the Yangtze River. The Yuan River basin supports diverse aquatic ecosystems and provides water for agriculture and industry in western Hunan. Downstream, the Yangtze River estuary and East China Sea receive the final discharge, making nutrient control critical for preventing eutrophication in coastal waters.

The plant discharges into the Xushui River, a tributary of the Yuan River, which flows into Dongting Lake and eventually the Yangtze River. The Yuan River basin is ecologically sensitive, supporting diverse freshwater species and providing critical habitat for migratory fish. Downstream, Dongting Lake is a large floodplain lake that plays a key role in water regulation and biodiversity in central China. Nutrient loading from wastewater can contribute to algal blooms in the lake and downstream Yangtze estuary, emphasizing the need for effective treatment.