Hole avlopsanlegg - Wastewater Treatment Plant in Hønefoss, Norway

Hole avlopsanlegg is a wastewater treatment plant located in Hønefoss, within the municipality of Hole in Buskerud county, Norway. The plant serves a population of approximately 4,660 people, placing it in the small to medium agglomeration category under Norwegian regulations. As a Norwegian facility, the plant operates under the national implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for discharges to freshwater and estuaries from agglomerations of this size. The plant discharges treated wastewater into the local watershed, which ultimately drains into the Tyrifjorden lake system. Tyrifjorden is one of Norway's largest lakes and supports diverse aquatic life, including important fish populations. The receiving waters are part of the Drammenselva river basin, which flows into the Drammensfjord and eventually the Oslofjord, a significant coastal ecosystem.

The plant's treated effluent enters the local watercourse, which flows into Tyrifjorden, a large lake in Buskerud. Tyrifjorden is an important freshwater habitat supporting fish species such as brown trout and Arctic char. The lake drains via the Drammenselva River into the Drammensfjord, a fjord that connects to the Oslofjord and the Skagerrak. This watershed is ecologically sensitive, with the lake and fjord supporting diverse aquatic life and serving as recreational and fishing areas.