Sichuan Wastewater Treatment Plant, Duoying Town, Ya'an | China

The Sichuan wastewater treatment plant is located in Duoying Town, Yucheng District, Ya'an, Sichuan Province, China. It serves a population of 231,000, classifying it as a medium-to-large agglomeration under Chinese wastewater management frameworks. The plant is situated in the upper reaches of the Yangtze River basin, a region characterized by mountainous terrain and significant ecological importance. As a facility serving over 200,000 people, the plant is expected to meet China's Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants (GB 18918-2002), which mandates secondary treatment with nutrient removal for plants in sensitive areas. Regulatory requirements for this scale typically include biological treatment and disinfection to protect downstream water quality. The plant discharges into local watercourses that flow into the Qingyi River, a tributary of the Dadu River, which eventually joins the Yangtze River. The downstream environment supports diverse aquatic life and provides water for agricultural and urban uses. Proper treatment is critical to prevent eutrophication and protect the ecological health of the Yangtze River system.

The plant's treated effluent enters local streams that drain into the Qingyi River, a major tributary of the Dadu River. The Dadu River flows into the Yangtze River, one of the world's largest river systems, which supports extensive biodiversity and provides water for millions of people. The upper Yangtze basin is ecologically sensitive, with habitats for endemic fish species and migratory birds. Effective wastewater treatment helps reduce nutrient loading and maintain water quality in this critical watershed.