A　three-stage　sequencing　batch　reactor　(SBR),　comprising　pretreating　SBR　(SBRpre),　nitritation　SBR　(SBRni),　and　anaerobic　ammonium　oxidation　(Anammox)　SBR　(SBRana),　was　developed　for　the　nitrogen　removal　from　mature　landfill　leachate.　The　concentrations　of　ammonia　and　chemical　oxygen　demand　(COD)　in　the　leachate　were　2000　+/-　100　and　2200　+/-　200　mg/L,　respectively.　About　100　mg/L　of　organic　substance　was　removed　from　SBRpre　to　reduce　the　negative　effect　on　the　Anammox　process　under　real-time　control.　After　acclimation　for　40　days,　the　nitrite　to　nitrogen　oxide　ratio　(NO2-/NOx)　in　SBRni　was　above　0.95.　The　nitrogen　removal　efficiency　reached　90%　in　SBRana,　and　nitrogen　load　rate　and　nitrogen　removal　rate　were　0.81　and　0.76　kg　N/(m(3)　d),　respectively.　The　continuous　filling　process　was　used　to　avoid　the　nitrite　inhibition　on　the　Anammox　activity.　The　quantitative　PCR　analysis　of　Anammox　indicated　the　average　Anammox　gene　ratio　increased　from　0.23%　to　4.77%　after　220　days　operation.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.