Nei Mongol Wastewater Treatment Plant, Ulanhot, Inner Mongolia

The Nei Mongol wastewater treatment plant is located in Ulanhot (乌兰浩特市), a city in the Hinggan League of Inner Mongolia, China. The facility serves a population equivalent of 223,000, classifying it as a medium-to-large urban agglomeration under Chinese wastewater management frameworks. China's wastewater treatment regulations, including the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), mandate secondary treatment with nutrient removal for plants of this scale. Typical facilities in this region employ activated sludge processes with biological nutrient removal to meet Class 1A or 1B discharge standards. The plant discharges treated effluent into local waterways that ultimately drain into the Nen River system, a tributary of the Songhua River basin. This watershed supports agricultural irrigation and aquatic ecosystems in northeastern China. The plant's location inland, over 50 km from the coast, reduces direct marine impact, but its discharge quality is critical for maintaining downstream water quality in the Songhua River basin.

The plant's treated effluent flows into the Nen River watershed, part of the larger Songhua River basin that drains into the Sea of Okhotsk via the Amur River. This region supports diverse freshwater habitats and is important for migratory fish species. The plant's discharge must comply with China's surface water quality standards to protect downstream agricultural and ecological uses.