Unnau GKA Wastewater Treatment Plant, Hachenburg, Germany

Unnau GKA is a municipal wastewater treatment plant located near Hachenburg in the Westerwaldkreis district of Rheinland-Pfalz, Germany. The plant serves a population of approximately 7,420 people, placing it in the small to medium agglomeration category under European Union classification. As a German wastewater treatment facility, Unnau GKA operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary treatment for agglomerations of this size. German federal and state regulations further ensure compliance with stringent effluent standards to protect water quality in the region. The plant discharges treated wastewater into local watercourses that ultimately drain into the Rhine River basin. The Westerwald region is characterized by its hilly terrain and numerous small streams, which feed into the Sieg or Lahn rivers, both tributaries of the Rhine. This makes proper treatment essential to protect downstream aquatic ecosystems and drinking water sources.

The plant's treated effluent flows into small streams in the Westerwald region, which are part of the Rhine River basin. These streams eventually join the Sieg or Lahn rivers, both major tributaries of the Rhine. The Rhine is a vital European waterway supporting diverse aquatic life, including migratory fish species such as salmon and eel. The Westerwald's forested landscape and moderate climate contribute to the ecological sensitivity of local water bodies, which require effective nutrient removal to prevent eutrophication downstream.