Martinsville STP Wastewater Treatment Plant, Martinsville, Illinois

Martinsville STP is a municipal wastewater treatment facility located in Martinsville, Clark County, Illinois. It serves a small community of 1,148 residents, providing essential sanitation services for the town. The plant operates under the regulatory framework of the United States 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 required for most municipal facilities in the U.S. Its designed capacity is 567.81 units, matching the current discharge volume, indicating full utilization. As a small-scale plant, it is subject to state-level oversight by the Illinois Environmental Protection Agency, which issues permits and ensures compliance with water quality standards. The treated effluent is discharged into a local waterway that ultimately drains into the Wabash River basin, a major tributary of the Ohio River. This watershed supports diverse aquatic life and provides drinking water for downstream communities. The plant's operation helps protect local streams from untreated sewage, reducing nutrient and pathogen loads in the regional water system.

The plant's discharge enters a small tributary within the Wabash River watershed, which flows into the Ohio River and eventually the Mississippi River. This inland basin supports a mix of agricultural and natural habitats, including wetlands that filter pollutants and provide wildlife corridors. The secondary treatment process reduces organic matter and suspended solids, helping maintain water quality for fish and other aquatic species in the downstream river system.