Johnson's Shut-Ins S P Wastewater Treatment Plant, Reynolds County, Missouri

Johnson's Shut-Ins S P is a wastewater treatment facility located in Reynolds County, Missouri, within the United States. The plant serves a small population of approximately 100 people, reflecting its role as a local-scale treatment facility in a rural area. It operates under the regulatory framework of the US Clean Water Act, which governs wastewater discharges through the National Pollutant Discharge Elimination System (NPDES) permit program. The plant provides secondary treatment, a standard level that removes biodegradable organic matter and suspended solids. With a designed capacity of 18.93 volume units and an actual discharge volume of 15.14, the facility operates below its capacity, indicating adequate headroom for current demand. Secondary treatment typically involves biological processes such as activated sludge or trickling filters. The treated effluent is discharged into the local watershed, which drains into the Black River and ultimately the Mississippi River system. This discharge contributes to the water quality of the region's streams and rivers, supporting aquatic life and downstream ecosystems. The plant's location inland, away from coastal areas, reduces direct marine impact but emphasizes the importance of protecting freshwater resources.

The plant discharges into the Black River basin, a tributary of the Mississippi River, which flows into the Gulf of Mexico. The local watershed supports diverse aquatic habitats, including cold-water streams that are home to sensitive species such as the Ozark hellbender. The secondary treatment level helps reduce pollutant loads, but the small population served means the plant's overall environmental footprint is limited.