HARDIN STP - Secondary Wastewater Treatment Plant in Hardin, Kentucky

HARDIN STP is a municipal wastewater treatment facility located in Hardin, Marshall County, Kentucky, serving a small community of 699 residents. The plant is situated near the Tennessee River watershed, which ultimately drains to the Ohio River and Mississippi River system. As a secondary treatment plant, it provides biological treatment to reduce organic pollutants and suspended solids before discharge. The plant has a designed capacity of 537.53 volume units and currently processes 423.97 volume units, indicating it operates below its design capacity. Under the US Clean Water Act, secondary treatment is the minimum standard for municipal wastewater plants, and facilities of this scale are typically regulated through the National Pollutant Discharge Elimination System (NPDES) permit program administered by the Kentucky Division of Water. The plant's treatment process meets the regulatory requirements for protecting water quality in the receiving water body. The plant's discharge enters local waterways that flow into the Tennessee River, a major tributary of the Ohio River. This river system supports diverse aquatic life and provides drinking water for downstream communities. The plant's location within 10 km of the coast (likely referring to the Tennessee River or nearby lakes) means its effluent can influence sensitive aquatic habitats. Proper secondary treatment helps minimize nutrient loading and protect downstream ecosystems.

The plant discharges into the Tennessee River basin, which flows into the Ohio River and eventually the Mississippi River. This watershed supports a variety of fish species and migratory birds. The area includes ecologically sensitive zones such as wetlands and backwater habitats that rely on good water quality. Secondary treatment reduces biochemical oxygen demand and total suspended solids, helping to maintain dissolved oxygen levels and prevent algal blooms in downstream waters.