STEP ST BRAIS Wastewater Treatment Plant, Saint-Brais, Jura, Switzerland

STEP ST BRAIS is a municipal wastewater treatment plant located in Saint-Brais, in the Jura canton of Switzerland. It serves a small population of 135 residents, reflecting the rural character of the Franches-Montagnes district. The plant is situated at an elevation in the Jura Mountains, a region known for its limestone karst landscape and forested hills. The plant provides secondary treatment, which is the standard biological treatment required under Swiss water protection legislation (Gewässerschutzgesetz). Swiss regulations mandate that all wastewater treatment plants achieve secondary treatment to protect sensitive water bodies. The plant has a designed capacity of 317 m³/day and currently discharges 61.28 m³/day, indicating it operates well below its capacity. The treated effluent from STEP ST BRAIS flows into the local river system, which eventually drains into the Rhine River basin via the Doubs River. The Doubs forms part of the border with France and is an ecologically important river supporting diverse aquatic life, including fish species such as brown trout. The plant's operation helps maintain water quality in this transboundary watershed.

The plant discharges into the Doubs River watershed, a tributary of the Rhine that flows through the Jura region and eventually reaches the North Sea. The Doubs is a karst-influenced river with sensitive aquatic ecosystems, including populations of native fish and macroinvertebrates. The surrounding Franches-Montagnes area features wetlands and peat bogs that rely on clean water inputs, making the plant's secondary treatment essential for protecting local biodiversity.