KA Orscholz Wastewater Treatment Plant, Mettlach, Saarland, Germany

KA Orscholz is a municipal wastewater treatment plant located in Orscholz, a district of Mettlach in the Saarland region of Germany. The plant serves a population of approximately 5,700 people, classifying it as a small to medium agglomeration under the EU Urban Waste Water Treatment Directive (91/271/EEC). Under the EU UWWTD, agglomerations of this size are generally required to provide secondary treatment (biological treatment) to remove organic matter and suspended solids. The plant operates within Germany's strict national water regulations, which implement the directive and often require advanced treatment in sensitive areas. The Saarland state environmental agency oversees compliance with discharge permits. The treated effluent from KA Orscholz is discharged into the local water system, which ultimately drains into the Saar River, a tributary of the Moselle River. The Moselle flows into the Rhine, one of Europe's major waterways, before reaching the North Sea. The plant plays a key role in protecting the water quality of these rivers and the downstream aquatic ecosystems.

KA Orscholz discharges into the local watershed that feeds the Saar River, a tributary of the Moselle River. The Moselle joins the Rhine, which flows through Germany and the Netherlands into the North Sea. The region's aquatic ecosystems support diverse fish populations and migratory species. The plant's treatment helps maintain water quality in this transboundary river system, which is ecologically sensitive and used for drinking water abstraction downstream.