Concentration and recovery of nitrogen from municipal solid waste leachate by means of forward osmosis and membrane contactor

• Forward Osmosis concentrated the sample around 2 times in terms of NH 4 + . • The flat sheet membrane 0.2 microns was the optimal one in terms of J_NH 3 and k m . • Sulphuric acid and higher pH were the optimal experimental conditions. • Acid concentrations it was not a significant parameter. • Forward Osmosis and membrane contactor are more effective used by separate. Municipal Solid Waste Leachate (MSWL) is a liquid waste generated in the composting of municipal solid waste or in landfills. This waste has a high organic matter concentration and a very high nutrients content, particularly ammoniacal nitrogen representing both an environmental liability and a potential resource. This study evaluates the operational performance and limitations of forward osmosis (FO) and membrane contactor (MC) processes, applied independently and a sequentially, as a favourable solution for recovering ammoniacal nitrogen from real MSWL. On one hand, forward osmosis was tested using (NH 4 ) 2 SO 4 as draw solution to concentrate ammonium in the feed solution (FS) achieving ammonium concentration factors up to 1.76 times, with water fluxes between 2.9-7.9 L·m⁻²·h⁻¹ depending on feed composition. On the other hand, for MC experiments, ammonia fluxes up to 33.54 g·m⁻²·h⁻¹ were obtained using a 0.2 μm polytetrafluoroethylene (PTFE) flat-sheet membrane with 0.1 M H₂SO₄ at pH 11. The integration of FO and MC revealed performance limitations associated with increased ionic strength and potential fouling effects in preconcentrated streams. These findings provide a critical assessment of the applicability boundaries of FO–MC integration for nitrogen recovery from highly variable real MSWL.