North Lake Poygan SD STP - Secondary Wastewater Treatment in Town of Wolf River, Wisconsin

North Lake Poygan SD STP is a municipal wastewater treatment facility located in the Town of Wolf River, Winnebago County, Wisconsin. The plant serves a small population of 562 residents and operates under the regulatory framework of the U.S. Clean Water Act, which requires secondary treatment for municipal discharges to surface waters. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 200.63 m³/day and an actual discharge volume of 189.27 m³/day, the facility operates near its design capacity. As a U.S. facility, it is subject to National Pollutant Discharge Elimination System (NPDES) permitting, administered by the Wisconsin Department of Natural Resources, which sets effluent limits to protect water quality. The treated effluent discharges into the Lake Poygan watershed, part of the larger Fox River basin that drains into Green Bay and ultimately Lake Michigan. This region supports diverse aquatic life and recreational uses, making effective wastewater treatment critical for maintaining water quality in the Great Lakes ecosystem.

The plant discharges into the Lake Poygan watershed, which flows via the Fox River into Green Bay and then Lake Michigan. Lake Poygan is a shallow, eutrophic lake that supports fish populations and migratory waterfowl. The downstream Fox River and Green Bay are ecologically sensitive areas that have experienced nutrient pollution, making the plant's secondary treatment important for controlling phosphorus and nitrogen loads to the Great Lakes basin.