Currently, most techniques for removal of compounds of emerging concern (CEC) are complex, expensive or energy demanding. Microalgae-based technologies have appeared as an emerging alternative. In this project, microalgae-based photobioreactors (PBRs) will be operated to study the removal of 18 CEC’s. The change of transformation products and eco-toxicity as well as the removal mechanisms will be investigated. Finally the optimal environmental and operational conditions for CEC removal will be defined and a 100 L pilot scale PBR will be tested. The outcomes will broaden the understanding of CEC removal by microalgae-based biotechnologies, which will serve as knowledge platform to implement new water treatment technologies in practice.