Wastewater Treatment Plants (WWTP) discharge complex effluents raising special concern and direct toxicity assessment can be an added value strategy in WWTP environmental protection. The EU project “Integrated approach to energy and climate changes: changing the paradigm of wastewater treatment management” was set up for a WWTP discharging into Tagus estuary (Portugal). The main objectives of the project are to implement a tool to optimize the management of WWTP in terms of energy efficiency and environmental impact and to reduce the environmental costs of the treatment process. Setting up adequate ecotoxicological methodologies and selecting a battery of ecotoxicity tests to be used in the characterization of WWTP wastewaters are the aim of this study. The results of a battery of tests demonstrated not only that the treatment efficiently reduced wastewater toxicity, but also that the use of an ecotoxicological approach can contribute to the environmental management of the Treatment Plant
