CEST2025

The disposal of sludge from wastewater treatment plants (WWTPs) is increasingly constrained by stringent landfill regulations. Biosolids, the treated residuals from WWTPs, offer a sustainable alternative for agricultural applications when their quality meets safety standards. This study evaluates the physicochemical properties and ecotoxicological effects of biosolids from three WWTPs in Northern Greece. Metal concentrations and toxicity to Daphnia magna neonates were assessed using the EN 12457-2 leaching test. The results showed low metal concentrations, below regulatory limits, but revealed mild toxicity to D. magna, regardless of biosolid origin or season. These findings highlight the need for further improvements in biosolid treatment for safe agricultural use.