Overview
MILLSTADT STP serves approximately 4,011 residents in Millstadt, Illinois. The plant discharges treated wastewater into local waterways under the US Clean Water Act framework.
MILLSTADT STP is a municipal wastewater treatment plant located at 299 South Kossuth Street in Millstadt, Illinois, a village in Saint Clair County. The facility serves a population of about 4,011 people, placing it in the small-agglomeration category typical of rural Midwestern communities. As a US-based plant, MILLSTADT STP operates under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Illinois Environmental Protection Agency. For a plant of this scale, secondary treatment is the standard requirement, ensuring that organic pollutants and suspended solids are reduced to levels protective of aquatic life. The plant's treated effluent flows into the Mississippi River basin, which ultimately drains to the Gulf of Mexico. This downstream connection places the facility within a watershed of national ecological significance, where nutrient management is critical to mitigating the Gulf of Mexico hypoxic zone.
Environmental context
MILLSTADT STP discharges into the Mississippi River watershed, a major drainage system that collects runoff from over 40% of the continental United States. The Mississippi River flows southward to the Gulf of Mexico, where nutrient loading from upstream sources contributes to seasonal hypoxia. The plant's location in the American Bottom region, a floodplain with rich agricultural activity, underscores the importance of effective wastewater treatment in protecting downstream water quality and aquatic habitats.
Frequently asked questions
MILLSTADT STP is located at 299 South Kossuth Street in Millstadt, Illinois, United States, within Saint Clair County.
The plant serves approximately 4,011 residents, classifying it as a small municipal wastewater treatment facility.
The plant discharges treated effluent into local waterways that are part of the Mississippi River basin, ultimately flowing to the Gulf of Mexico.
As a US facility, MILLSTADT STP operates under the Clean Water Act and is required to have an NPDES permit issued by the Illinois Environmental Protection Agency, which sets effluent limits to protect water quality.
For small agglomerations of this size, secondary treatment is standard under the Clean Water Act, which typically involves biological processes to reduce biochemical oxygen demand and suspended solids.
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