Due　to　the　difficulty　in　removing　nitrogen　from　landfill　leachate,　a　combined　continuous-flow　process　of　nitritation　and　anammox　was　applied　to　process　mature　leachate.　The　transformation　rate　of　ammonia　and　nitrite　accumulation　ratio　in　A/O　reactor　were　kept　above　95%　and　92%　respectively　through　associated　inhibition　of　free　ammonia　(FA)　and　free　nitrous　acid　(FNA)　to　NOB.　The　total　nitrogen　volumetric　load　of　anammox　in　an　UASB　reactor　was　brought　up　from　0.5　kg/(m(3).d)　to　1.2　kg/(m(3).d)　by　gradually　increasing　influent　substrate　concentration　and　reducing　hydraulic　retention　time　(HRT).　The　results　show　that　COD　from　mature　leachate　did　not　bring　obvious　inhibition　effects　to　anammox.　Under　concentrations　of　influent　ammonia　and　COD　which　were　respectively　1330　mg/L　and　2250　mg/L,　the　removal　efficiencies　of　TN　and　COD　reached　94%　and　62%　respectively.　In　the　quantitative　PCR　reactions,　the　proportions　occupied　by　AOB,　NOB　and　anammox　in　A/O　were　11.39%,　1.76%　and　0.05%　respectively;　and　proportions　of　those　in　UASB　were　0.35%,　4.01%　and　7.78%　respectively.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.