Investigation of the pollution load of urban wastewater treatment plants in Türkiye using grey water footprint analysis

This study evaluates the environmental sustainability of three different Urban Wastewater Treatment Plants (WWTPs) in Türkiye by employing the Grey Water Footprint (GWF) and Water Pollution Level (WPL) indicators. The assessment covers various treatment technologies, including conventional activated sludge (CAS) and advanced biological treatment, across different hydrological regimes in Ankara and Kastamonu provinces. Results indicate that nutrient-related parameters, particularly TP, dominate the GWF across all facilities. The WPL analysis revealed that the natural assimilation capacity of the receiving water bodies is significantly overstressed, with WWTP2 reaching a critical WPL of 38.01 for phosphorus due to low river flow. While WWTP3 showed sustainable levels for organic matter (WPL < 1). These findings highlight that meeting legal discharge limits is insufficient to ensure ecological health, necessitating a transition toward load-based management and advanced nutrient removal to protect sensitive aquatic ecosystems.