One　lab-scale　biofilter　coupling　nitrification　and　anaerobic　ammonium　oxidation　(ANAMMOX)　that　simultaneously　removes　Fe,　Mn　and　ammonia　from　simulated　groundwater　was　adopted　to　investigate　the　influence　of　Mn　and　ammonia　on　nitrogen　conversion　and　Mn　removal　kinetics　in　this　study.　The　results　showed　that　autotrophic　nitrogen　removal　proportion　(ANRP)　rose　slightly　with　the　raise　of　Mn　concentration　and　declined　along　with　the　raise　of　ammonia;　the　average　ratios　were　49.6%,　51.5%,　51.8%,　52.3%,　52.6%,　48.9%,　47.4%　and　38.8%,　respectively.　Relative　constant　or　slight　down　trend　of　accumulated　ANRP　was　detected　in　filter　bed　which　indicated　the　superiority　of　nitrification　in　relevant　areas.　After　reaching　a　certain　value,　Mn　could　promote　ANAMMOX　in　the　upper　part　of　the　filter　bed　and　shorten　the　main　ammonia　conversion　area.　As　ammonia　content　rising,　the　maximum　accumulated　ANRP　reduced　and　the　maximum　value　acquired　height　went　up.　Moreover,　the　ammonia　inhibition　threshold　for　ANAMMOX　in　the　biofilter　might　be　different　from　waste　water　treatment.　Mn　removal　could　be　assessed　by　first　order　reaction　in　all　the　eight　periods　and　the　k　values　were　more　comparable　than　those　in　abiotic　Mn　oxidation.　(C)　2018　Elsevier　B.V.　All　rights　reserved.