Catawissa WWTP - Secondary Treatment Plant in Catawissa, Missouri

Catawissa WWTP is a municipal wastewater treatment facility located on Frisco Drive in Catawissa, Franklin County, Missouri. The plant serves a population of approximately 1,294 residents and operates under the regulatory framework of the U.S. Clean Water Act, which requires secondary treatment for municipal discharges. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 1,892.70 m³/day and an actual discharge volume of 378.54 m³/day, the facility operates well below its capacity, indicating room for future growth. As a small-scale plant, it is subject to EPA National Pollutant Discharge Elimination System (NPDES) permitting, administered by the Missouri Department of Natural Resources. The treated effluent is discharged to a receiving water body that ultimately drains into the Mississippi River basin. This watershed supports diverse aquatic life and provides drinking water for downstream communities. The plant's inland location reduces direct marine impact, but its discharge contributes to the overall water quality of the regional river system.

The plant discharges into a tributary of the Meramec River, which flows into the Mississippi River south of St. Louis. The Meramec River is a biologically diverse system supporting over 100 fish species and numerous mussel populations. Downstream, the Mississippi River carries the effluent through the Mississippi Delta to the Gulf of Mexico, where nutrient loading can contribute to hypoxic zones. The plant's secondary treatment helps reduce organic pollutants but does not remove nutrients like nitrogen and phosphorus, which are relevant to downstream eutrophication concerns.