QULIN WWTP - Secondary Wastewater Treatment in Qulin, Missouri

QULIN WWTP is a municipal wastewater treatment facility located in Qulin, a small town in Butler County, Missouri, United States. The plant serves a population of 458 residents and operates under secondary treatment standards, which is the minimum required by the US Clean Water Act for municipal wastewater treatment. The facility discharges approximately 170.34 thousand cubic meters of treated effluent annually, with a designed capacity of 378.54 thousand cubic meters per year. The plant's treatment process is secondary, involving biological treatment to reduce organic matter and suspended solids. As a small-scale facility, it is subject to US EPA National Pollutant Discharge Elimination System (NPDES) permitting, which sets effluent limits based on the receiving water body's assimilative capacity. The plant's capacity utilization suggests it operates well below its design capacity, indicating potential for future growth or seasonal flow variations. The treated effluent is discharged into a local water body, likely a tributary of the St. Francis River, which flows into the Mississippi River and ultimately the Gulf of Mexico. The plant plays a key role in protecting local water quality in the rural Missouri Bootheel region, an area characterized by agricultural activity and flat terrain.

The plant's discharge enters a local stream that drains into the St. Francis River, a major tributary of the Mississippi River. The Mississippi River carries the effluent to the Gulf of Mexico, contributing to the vast Mississippi River Basin. The region's aquatic ecosystems support diverse fish and wildlife, and the plant's secondary treatment helps reduce nutrient loading that could contribute to hypoxia in the Gulf.