Adsorption-membrane hybrid systems present an interesting alternative for the treatment of contaminated waters. This study aims to understand the role of NOM on membrane performance and on removal of pharmaceuticals during the combined application of powdered activated carbon and submerged membranes. A focus was on investigations of the interactions between particles, membrane surface and NOM constituents and how they affect membrane filtration. PAC-particles played a minor role in the flux decline during filtration of demineralised water and phosphate puffer (pH value = 7). Filtration experiments in the presence of NOM resulted in the formation of irreversible fouling, of a thick cake layer and thus a significant flux. decline. The results suggest that NOM can bridge PAC particles together and to the membrane surface so that they become part of the foulants in the hybrid system. The pharmaceuticals were rejected in the hybrid system predominantly more than 99.8% and the removal of DOC was about 60%.