Wechselland Monichwald Wastewater Treatment Plant, St. Lorenzen, Austria

Wechselland Monichwald is an advanced wastewater treatment plant located in St. Lorenzen, in the district of Hartberg-Fürstenfeld, Steiermark, Austria. The plant serves a small community of approximately 1,209 people, reflecting its role in rural wastewater management within the region. As an advanced treatment facility, it goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, which is typical for plants operating under the EU Urban Waste Water Treatment Directive (91/271/EEC). The advanced level indicates compliance with stringent effluent standards for sensitive areas. The plant has a designed capacity of 2,573 m³/day and currently discharges 277 m³/day, indicating ample reserve capacity. The treated effluent is discharged into local watercourses that ultimately drain into the Lafnitz River, a tributary of the Raab River, which flows into the Rába River in Hungary and eventually reaches the Danube River basin. This downstream connection highlights the plant's role in protecting the ecological health of the Danube watershed, supporting aquatic life and water quality in the region.

The plant discharges into the Lafnitz River basin, which flows into the Raab River and then the Rába River, part of the Danube catchment. This watershed supports diverse aquatic habitats and is important for migratory fish species. The advanced treatment helps reduce nutrient loading, protecting downstream ecosystems from eutrophication.