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Advanced leachate treatment become more and more urgent for the sharp increasing of solid waste and sanitary landfills in China.In this study,anoxic and aerobic membrane bioreactors (A/O-MBR) system combined with nanofiltration (NF) and reverse osmosis (RO) membranes were applied to treat the industrial landfill leachate.The MBR with a biomass concentration (MLSS) of 4-5 g/L showed a high efficiency in leachate treatment.On average,the removal of chemical oxygen demand (COD) and ammonia-nitrogen (NH3-N)were 81.5% and 94.0%,respectively.After MBR treatment,although the effluent still contained 472.8-710.4mg/L COD and 18.0-39.0 mg/L NH3-N,the amount of high-valence metal ions decreased more than low-valence ones.Fe decreased by 98.1% with an initial concentration of 3.018mg/L,while Na and K decrease only 0.3 %and 1.4 % respectively.Membrane fouling was observed with the increase of membrane resistance.According to the resistance analysis,39.1% of the total resistance contributed to the cake layer,while 19.2 % to organic fouling and 22.5 % to inorganic fouling.NF and RO membranes were then used to futther treat the MBR effluent.In NF filtration,COD and NH3-N decreased to 276.25 mg/L and 26.55 mg/L respectively,while a total salt rejection of 15-20% indicated a worse desalination.However,it was found that the chromaticity obviously decreased from 125 (times) to 8 (times).Based on NF pretreatment,RO membrane held a relatively high flux in operation.The final permeate from RO membrane contained no heavy metals and had little contents of COD and NH3-N as low as 12.9mg/L and 2.6mg/L respectively,which proved to exceed the related qualification and can be reused in industry very well.