COV Zemianska Olca Wastewater Treatment Plant, Zemianska Olča, Slovakia

COV Zemianska Olca is a wastewater treatment plant located in Zemianska Olča, a village in the Komárno district of Nitriansky kraj, western Slovakia. The plant provided secondary treatment for municipal wastewater, serving the local population as part of the region's sanitation infrastructure. As a secondary treatment facility, the plant met the minimum requirements under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of its scale. The directive mandates secondary biological treatment for communities with a population equivalent above 2,000, ensuring effective removal of organic matter and suspended solids before discharge. The plant's treated effluent was discharged into local waterways that drain into the Danube River basin, ultimately reaching the Black Sea. The surrounding area is part of the Danubian Lowland, an ecologically sensitive region supporting diverse aquatic life and agricultural activities. Proper wastewater treatment is crucial for protecting downstream water quality and biodiversity.

The plant's discharge contributed to the local hydrological network within the Danube River basin, which flows into the Black Sea. This region supports diverse aquatic ecosystems and is important for migratory fish species. Effective treatment helps prevent nutrient pollution and maintains water quality in downstream rivers and wetlands.