Hunan Wastewater Treatment Plant, Xinshao County, Hunan Province

The Hunan wastewater treatment plant is located in Xinshao County, Shaoyang City, Hunan Province, China. It serves a population of approximately 137,400 people, classifying it as a medium-to-large agglomeration under Chinese wastewater management frameworks. As a plant in China, it is subject to the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), which sets effluent limits for conventional pollutants, nutrients, and pathogens. For plants of this scale, secondary treatment with nutrient removal is typically required, especially in sensitive watersheds. The plant discharges treated effluent into a local water body that ultimately drains into the Zi River, a tributary of the Xiang River, which flows into Dongting Lake and then the Yangtze River. The downstream environment supports diverse aquatic life and provides water for agricultural and industrial use.

The plant's treated effluent enters a local watercourse that feeds into the Zi River, part of the Xiang River basin. The Xiang River flows into Dongting Lake, a large freshwater lake that regulates flooding and supports wetland ecosystems. Downstream, the Yangtze River receives the combined flow, impacting water quality in one of China's most important river systems. The region's aquatic habitats are sensitive to nutrient loading and industrial pollutants.