Humphreys WWTP - Secondary Treatment Plant in Sullivan County, Missouri

Humphreys WWTP is a municipal wastewater treatment plant located in Sullivan County, Missouri, United States. The facility serves a small population of 105 residents and provides secondary treatment, which is the minimum standard required by the U.S. Clean Water Act for domestic wastewater. The plant's designed capacity is 49.21 megaliters, with an annual discharge volume of 37.85 megaliters. As a secondary treatment plant, Humphreys WWTP uses biological processes to remove organic matter and suspended solids. The plant is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits to protect water quality. For small agglomerations like this, secondary treatment is typically sufficient to meet environmental standards. The treated effluent from Humphreys WWTP is discharged into local waterways that eventually drain into the Mississippi River basin. The receiving water body supports aquatic life and is part of a larger watershed that flows to the Gulf of Mexico. The plant's operation helps maintain water quality in this inland region, reducing nutrient and pollutant loads downstream.

The treated effluent from Humphreys WWTP enters local streams within the Mississippi River basin, which ultimately drains into the Gulf of Mexico. This region is part of a large agricultural watershed where nutrient pollution is a concern, contributing to hypoxic zones in the Gulf. The plant's secondary treatment helps reduce organic and nutrient loads, supporting downstream aquatic ecosystems.