RESUMO
Recovery of high quality water from municipal landfill leachate was studied by three-stage disc tube reverse osmosis optimized in pilot-scale. Following UF-membrane-assisted activated sludge plant, overall 46.5â¯tons of leachate were post-treated in real environment and analyzed for conventional contaminants and hazardous compounds (e.g. heavy metals, boron, selenium) throughout operation of membrane system. Operating pressure ranged from 21 to 76â¯bar, while permeate flux varied in the range 7.1-32.5â¯Lâ¯m-2â¯h-1. Rejection factors of specific ions were related to the pressure and global removals were assessed for each stage (e.g. E%CODâ¯=â¯92.4-99.2%, E%NH4â¯=â¯46.2-95.8%, E%NOxâ¯=â¯84.8-97.9%; E%TDSâ¯=â¯88-95.5%). Boron removal was assessed in the range 34-48%, so as to require the third stage to reach standard for discharge or reuse. Two stages were sufficient to reach water recovery higher than 91%. Long-term operation and mathematical modeling demonstrated how the Δπ/ΔP ratio can support the decisions for membrane cleaning and predictive maintenance: permeability decline was associated to the ratio increase from 0.72 to 0.73 to 1.13-1.21.