Cartwright Creek STP: Wastewater Treatment Plant in River Rest, Tennessee

Cartwright Creek STP is a wastewater treatment facility located in River Rest, Williamson County, Tennessee. The plant serves a small population of approximately 1,000 residents and operates under the regulatory framework of the United States Clean Water Act, which requires secondary treatment for municipal wastewater discharges. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 946.35 thousand cubic meters, the plant currently treats an annual volume of 340.69 thousand cubic meters, indicating operational capacity well below its design limit. The treated effluent is discharged into a local waterway that ultimately drains into the Cumberland River basin, a major tributary of the Ohio River and Mississippi River system. The plant's location in inland Tennessee means its discharge contributes to freshwater ecosystems rather than coastal or marine environments.

The plant discharges into a tributary of the Cumberland River, which flows through Tennessee and Kentucky before joining the Ohio River. The Cumberland River watershed supports diverse aquatic life, including several species of freshwater mussels and fish. Downstream, the Ohio River feeds into the Mississippi River, which empties into the Gulf of Mexico, making the plant's nutrient management relevant to the Gulf's hypoxic zone.