Forward Osmosis (FO) has been designed and studied for various applications due to the advantages it offers when compared to traditional pressure-driven membrane processes. In our previous study, seawater-driven forward osmosis was successfully applied to concentrate nutrients in treated municipal wastewater. In this study, the long-term operational stability and performance of the seawater-driven FO process was investigated by a 2-month continuous operation of bench-top FO reactors. Nitrification inhibition was recommended to maintain the concentration performance of nitrogen by preventing ammonia from being oxidized by microorganisms. With nitrification inhibition, concentration performances of 3- to 4-fold of total phosphorus and 2.1-fold of ammonia were stably achieved at a feed volume reduction of 75%. Membrane fouling, with the active layer of the FO membrane facing the feed solution, had only a mild impact; there was approximately 5% water flux reduction but no significant effect on nutrient enrichment performance. The analytical results by FTIR and SEM-XMA suggested that bio-fouling with a combined structure of bacterial clusters, biopolymers, and slight inorganic scales was the main FO membrane fouling pattern. Furthermore, pre-disinfection performed in feed solution effectively retarded the occurrence of membrane fouling in the FO process. (C) 2015 Elsevier B.V. All rights reserved.