Granger WWTP - Secondary Treatment Plant in Dallas County, Iowa

Granger WWTP is a municipal wastewater treatment facility located in Dallas County, Iowa, serving a population of 1,250. The plant provides secondary treatment, a standard level for small communities in the United States, ensuring that effluent meets federal and state water quality standards before discharge. The plant has a designed capacity of 3,974.67 volume units and currently processes an average daily flow of 707.87 volume units, indicating it operates well below its capacity. As a US facility, it operates under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits and monitoring requirements to protect receiving waters. The treated effluent from Granger WWTP is discharged into local streams that drain into the Des Moines River basin, ultimately reaching the Mississippi River. This watershed supports diverse aquatic life and provides drinking water for downstream communities. The plant's secondary treatment helps reduce organic pollutants and suspended solids, contributing to the ecological health of the region.

Granger WWTP discharges into the Des Moines River watershed, which flows into the Mississippi River, a major waterway supporting extensive aquatic ecosystems and migratory bird routes. The plant's secondary treatment reduces nutrient loads, helping to mitigate downstream eutrophication in the Gulf of Mexico. The local watershed is primarily agricultural, and the plant's effluent management is crucial for maintaining water quality in streams that serve as habitat for fish and macroinvertebrates.