A　modified　sequencing　batch　reactor　(SBR)　operated　at　the　anaerobic-aerobic-anoxic　mode　was　developed　in　this　study　to　fully　utilize　the　organics　in　landfill　leachate　(ammonia　concentration　of　1000　+/-　50　mg　N/L　and　COD/total　nitrogen　(TN)　ratio　of　1-4).　The　unique　feature　of　modified　SBR　process　was　the　addition　of　an　anaerobic　stage　after　feeding　stage,　so　that　microorganisms　could　store　the　organics　during　anaerobic　stage　and　supply　the　carbon　source　for　endogenous　denitritation　after　aeration　stage.　The　70-day　operational　tests　showed　the　effluent　TN　was　below　10　mg　N/L　at　C/N　ratio　of　4.　The　intracellular　stored　polymers　were　analyzed　and　the　microorganisms　were　capable　of　storing　the　carbon　source　as　polyhydroxybutyrate　(PHB)　and　glycogen　in　anaerobic　stage,　which　were　the　electron　donors　for　endogenous　denitritation.　Fluorescence　in　situ　hybridization　(FISH)　analysis　showed　that　glycogen　accumulating　organisms　(GAOs)　account　for　39.8%　of　microorganisms　in　SBR,　and　carried　out　advanced　nitrogen　removal.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.