Walnut WWTP | Secondary Treatment Plant in Pottawattamie County, Iowa

Walnut WWTP is a municipal wastewater treatment facility located in Pottawattamie County, Iowa, United States. The plant serves a small population of 1,035 residents in the rural community of Layton Township and surrounding areas. As a secondary treatment plant, it provides biological treatment to remove organic matter and suspended solids from wastewater before discharge. The plant operates under the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater facilities. The National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Iowa Department of Natural Resources, governs the plant's discharge limits and monitoring requirements. The plant's designed capacity is 492.10 megaliters per year, and it currently discharges 847.93 megaliters per year, indicating it operates within its capacity. The treated effluent from Walnut WWTP is discharged into local waterways that drain into the Missouri River watershed, which ultimately flows into the Mississippi River and the Gulf of Mexico. The plant plays a key role in protecting water quality in the region by reducing nutrient and pollutant loads to downstream ecosystems.

Walnut WWTP discharges into tributaries of the Missouri River, which flows into the Mississippi River and eventually the Gulf of Mexico. The plant's secondary treatment helps reduce the risk of eutrophication and hypoxia in downstream waters, including the Gulf of Mexico's dead zone. The surrounding area is primarily agricultural, so the plant's nutrient removal is important for mitigating nonpoint source pollution.