Within the project OXERAM state of the art membrane filtration was applied as a tertiary treatment step for advanced phosphorus removal in a municipal wastewater treatment plant. Two membrane types, ceramic and polymeric, were tested in pilot scale, using commercial membrane modules. Due to the drawback of membrane fouling, leading to comparably high investment and operating costs, pre-treatment with ozone was tested. Ozonation was expected to increase the sustainable flux for both membrane types. For both membranes types high filtrate quality was achieved. A mean total phosphorus concentration below 25 µg/L was achieved over two years. Additionally disinfection is reached and therefore the European bathing water standards were met. The effect of ozonation and coagulation on various water quality parameters were evaluated and are presented in this report. Ultrafiltration modules (0.02 µm) made of polyether sulfone (PES) were tested comparing different capillary diameters (0.9 vs. 1.5 mm) leading to different package densities (respectively 40 and 60 m2 per module). Both types were operated in parallel and the experience showed a more robust operation with 1.5 mm capillaries when applying high fluxes targeting high recoveries. Both evaluation parameters, total fouling rate and membrane regeneration by cleaning in place, suggested the 1.5 mm module for the application at the WWTP Ruhleben. Optimizing the operation set up and cleaning strategy proved that recoveries = 95 % could be achieved and therefore a second filtration unit treating the backwash water is obsolete. The design with max 75 L/(m2h), 60 minutes of filtration, and a backwash duration of 40 s is the proposed set up for WWTP Ruhleben. A daily acidic chemical enhanced backwash combined with a weekly caustic cleaning step proved to manage the fouling affinity and a cleaning in place interval of 1 – 3 months was demonstrated in a long term run. The usage of ozone did not improve the overall filtration performance, because the benefit of a higher filterability is compensated by a higher additional fouling resistance after each backwash. Therefore the mean trans-membrane pressure remains in the same range. These results were only collected with the combination of ozonation and PES ultrafiltration membranes. Lab scale tests conducted at the Chair of Water Quality, TU Berlin, confirm this outcome but showed different results for other membrane materials and pore sizes. The potential to reduce the total fouling rate combining ozonation with coagulation prior ceramic membrane filtration was shown. A microfiltration membrane (0.1 µm) consisting of Al2O3 and a surface of 25 m2 was tested in pilot scale. Applying a dose of 15 mgO3/L (z = 1.18 mgO3/mgDOC) could reduce the total fouling rate by half even when doubling the flux from 60 L/(m2h) to 120 L/(m2h). Critical flux experiments showed that the application of 7.5 mgO3/L (z = 0.7 mgO3/mgDOC) was sufficient to recognize the beneficial effect of pre-ozonation. Treating the secondary effluent of WWTP Ruhleben a sustainable flux around 130 – 140 L/(m2h) was identified when applying pre-ozonation of 7.5 mgO3/L (z = 0.7 mgO3/mgDOC) and 8 mgFe/L for coagulation. It was not possible to demonstrate this process set up in a long term run, due to technical malfunctions. An economic evaluation showed however that for the case of WWTP Ruhleben a sustainable flux > 500 L/(m2h) is required to be competitive against tertiary treatment with polymeric membranes without ozone. This high value can be explained by the high module cost for ceramic membranes and the high DOC content of the secondary effluent, leading to increased effort for ozonation.