Nitritation　can　be　used　as　a　pretreatment　for　anaerobic　ammonia　oxidation　(anammox).　Various　control　strategies　for　nitritation　and　half-nitritation　of　old　landfill　leachate　in　a　membrane　bioreactor　were　investigated　in　this　study　and　the　inhibition　kinetics　of　substrate,　product　and　old　landfill　leachate　on　nitritation　were　analyzed　via　batch　tests.　The　results　demonstrated　that　old　landfill　leachate　nitritation　in　the　membrane　bioreactor　can　be　achieved　by　adjusting　the　influent　loading　and　dissolved　oxygen　(DO).　From　days　105-126　of　the　observation　period,　the　average　effluent　concentration　was　871.3　mg/L　and　the　accumulation　rate　of　NO2-　-N　was　97.2%.　Half-nitritation　was　realized　quickly　by　adjusting　hydraulic　retention　time　and　DO.　A　low-DO　control　strategy　appeared　to　best　facilitate　long-term　and　stable　operation.　Nitritation　inhibition　kinetic　experiments　showed　that　the　inhibition　of　old　landfill　leachate　was　stronger　than　that　of　the　substrate　(NH4+　-N)　or　product　(NO2-　-N).　The　ammonia　oxidation　rate　dropped　by　22.2%　when　the　concentration　of　old　landfill　leachate　(calculated　in　chemical　oxygen　demand)　was　1600.2　mg/L;　further,　when　only　free　ammonia　or　free　nitrous　acid　were　used　as　a　single　inhibition　factor,　the　ammonia　oxidation　rate　dropped　by　4.7-6.5%　or　14.5-15.9%,　respectively.　Haldane,　Aiba,　and　a　revised　inhibition　kinetic　model　were　adopted　to　separately　fit　the　experimental　data.　The　R-2　correlation　coefficient　values　for　these　three　models　were　0.982,　0.996,　and　0.992,　respectively.　(C)　2016,　The　Society　for　Biotechnology,　Japan.　All　rights　reserved.