Lillehammer renseanlegg - Municipal Wastewater Treatment Plant in Lillehammer, Norway

Lillehammer renseanlegg is the primary wastewater treatment facility for the city of Lillehammer, located in Innlandet county, Norway. The plant serves a population of about 93,600, classifying it as a large agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). As a Norwegian facility, it adheres to national regulations that transpose the UWWTD, requiring secondary treatment as a minimum for such population scales. However, under the UWWTD, agglomerations of this size in sensitive areas must achieve tertiary treatment to reduce nutrients. Norway's implementation of the directive includes strict requirements for phosphorus and nitrogen removal to protect its numerous lakes and fjords. The plant is located inland, approximately 50 km from the coast, and discharges into the local watershed. The treated effluent from Lillehammer renseanlegg ultimately drains into the Mjøsa lake, Norway's largest lake, via the river Lågen. Mjøsa is a critical freshwater resource for the region, supporting drinking water, recreation, and diverse aquatic life. The plant plays a vital role in maintaining water quality in this sensitive ecosystem, preventing eutrophication and protecting downstream environments.

The plant discharges into the river Lågen, which flows into Lake Mjøsa, Norway's largest lake. Mjøsa is a deep, oligotrophic lake that serves as a drinking water source for over 100,000 people and supports a rich ecosystem including the endangered European eel. The lake is sensitive to nutrient inputs, making advanced treatment essential to prevent algal blooms and maintain water quality. The watershed ultimately drains to the Glomma river and then to the Oslofjord, a coastal ecosystem of ecological significance.