Developing a novel technology to remove micro pollutants from wastewater effluent. The idea is to combine a powerful chemical treatment (ozone) with microorganisms (bio filtration) to create an efficient and cost effective technology, with the final aim to scale up the technology for application at a municipal wastewater treatment plant. In the thesis we study three aspects: 1 what type of biofiltration has the best synergy with the ozonation and how should the biofiltration reactor be operated, 2 how do the different types organic matter present in a wastewater effluent matrix affect the ozonation of micropollutants, and 3 what is the chemical and toxicological water quality after the biofiltration – ozone treatment. All results can be used to optimize the micropollutant removal process, maximizing removal of both chemical and toxicological parameters and minimizing the required energy input.