COLOMBIERLA SAUNERIE Wastewater Treatment Plant, Milvignes, Switzerland

COLOMBIERLA SAUNERIE is a wastewater treatment plant located in Milvignes, in the canton of Neuchâtel, Switzerland. It serves a population of approximately 27,668 people, placing it in the medium agglomeration category. The plant is situated near the shores of Lake Neuchâtel, the largest lake entirely within Switzerland. As a Swiss facility, the plant operates under the Swiss Water Protection Act (Gewässerschutzgesetz), which mandates advanced treatment for discharges into sensitive water bodies. For agglomerations of this size, secondary treatment with nutrient removal is typically required to protect the lake ecosystem. The plant's design capacity and treatment processes are aligned with these national standards. The treated effluent is discharged into Lake Neuchâtel, which is part of the Rhine basin via the Zihl Canal and the Aare River. The lake supports diverse aquatic life and is an important recreational and ecological resource. The plant plays a key role in maintaining water quality in this sensitive lacustrine environment.

The plant discharges into Lake Neuchâtel, the largest lake entirely within Switzerland. The lake drains via the Zihl Canal into the Aare River, which eventually flows into the Rhine and the North Sea. The lake supports a rich ecosystem, including fish species such as perch and whitefish, and is a vital habitat for migratory birds. Protecting water quality is essential for both ecological health and recreational use.