Physico-chemical parameters alone are not sufficient in obtaining reliable information on treated wastewater. Online toxicity monitoring must be performed in combination with routine chemical analysis. The assessment of biological effects of wastewater discharges in the ecosystems is today considered relevant and ecotoxicological tests identifying the ecological hazard are useful tools for the identification of environmental impacts.

Online toxicity monitoring can play an important role in supporting decision-making, either regulatory driven or needed for process control .

To comply with good ecological status, ecotoxicity evaluation of WWTP effluents is extremely relevant. Within the Integrated Pollution Prevention and Control Directive – IPPC, 2008/1/EC (European Commission [EC], 2008), the Direct Toxicity Assessment concept has been included as a suitable monitoring tool on effluent in several Best Available Techniques (BAT) Reference Documents. Also, in Water Framework Directive – WFD, 2000/60/EC (EC, 2000), direct toxicity assessment of Wastewater Treatment Plant (WWTP) effluents can contribute to attain or keep ecological quality objectives in water masses. Online toxicity monitoring using the TOXcontrol with the luminescent bacteria can help with the protection of biological treatment plants from toxic influents, to monitor the effectiveness of WWTP and control the impact assessment of complex wastewaters. The TOXcontrol can be considered as a suitable tool for assessing the ecotoxicological relevance of complex organic mixtures.