Krottendorf Preding Wastewater Treatment Plant, Weiz, Steiermark

Krottendorf Preding is an advanced wastewater treatment plant located in the municipality of Preding, near Weiz, in the state of Steiermark, Austria. The plant serves a population of approximately 2,096 people and has a design capacity of 3,000 cubic meters per day, with an average discharge volume of 540.47 cubic meters per day. As an advanced treatment facility, the plant 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). This directive requires advanced treatment for agglomerations discharging into sensitive areas, and Austria has designated many water bodies as sensitive to eutrophication. The plant's treated effluent is discharged into local watercourses that ultimately drain into the Danube River basin, contributing to the protection of the Black Sea ecosystem. By providing advanced treatment, the plant helps maintain water quality in the region's streams and rivers, supporting aquatic life and downstream uses.

The plant discharges into small streams near Preding, which flow into the Raab River, a tributary of the Danube. The Danube carries water through several countries before reaching the Black Sea. The region's watershed supports diverse aquatic habitats, and advanced treatment helps prevent nutrient over-enrichment that could harm downstream ecosystems, including the ecologically sensitive Danube Delta.