Heiligenbrunn Wastewater Treatment Plant, Hagensdorf, Burgenland, Austria

Heiligenbrunn wastewater treatment plant is located in Hagensdorf, a village in the municipality of Heiligenbrunn, Bezirk Güssing, Burgenland, Austria. The plant serves a population of approximately 1,789 people, classifying it as a small agglomeration under Austrian and EU regulations. The plant employs advanced treatment processes, which go beyond the EU Urban Waste Water Treatment Directive's minimum requirement of secondary treatment for agglomerations of this size. With a designed capacity of 2,500 m³/day and an actual discharge volume of 516.91 m³/day, the plant operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that drain into the Raab River system, which flows into the Rába River in Hungary and ultimately reaches the Danube River. The plant's advanced treatment helps protect the sensitive aquatic ecosystems of the Raab basin, which supports diverse fish populations and migratory birds.

The Heiligenbrunn plant discharges into the Raab River basin, a tributary of the Rába River that flows into the Danube. This watershed supports ecologically sensitive habitats, including wetlands and floodplain forests that provide critical spawning grounds for fish and stopover sites for migratory waterbirds. Advanced treatment at the plant reduces nutrient loads, helping to prevent eutrophication downstream in the Danube and the Black Sea.