The　effect　of　the　heavy　rare　earth　element　erbium　[Er(Ⅲ)]　on　the　short-term　and　long-term　nitrogen　removal　efficiency　of　the　short-cut　nitrification　process　was　studied,　and　the　related　kinetic　analysis　was　carried　out.　Short-term　experiments　showed　that　Er(Ⅲ)　at　the　concentration　of　0—10mg/L　promoted　the　activity　of　AOB　bacteria,　20—60mg/L　Er(Ⅲ)　slightly　inhibited　the　activity　of　AOB　bacteria,　and　80—120mg/L　Er(Ⅲ)　showed　severe　inhibition　on　the　activity　of　AOB　bacteria.　AOB　bacteria　would　adsorb　a　large　amount　of　Er(Ⅲ),　and　the　Er(Ⅲ)　removal　rate　was　greater　than　90%　when　the　influent　Er(Ⅲ)　concentration　was　lower　than　60mg/L.　However,the　Er(Ⅲ)　removal　rate　gradually　decreased　when　the　influent　Er(Ⅲ)　concentration　was　higher　than　60mg/L.　The　results　of　ICP-MS　and　EDS　analysis　showed　that　Er(Ⅲ)　could　be　adsorbed　extracellularly　and　uptaked　intracellularly　by　AOB　bacteria,　and　the　extracellular　adsorption　was　the　main　one.　The　experimental　results　were　fitted　by　Vadivelu　model,　Hellinga　model,　Michaelis-Menten　model　and　Hill　model,　respectively.　The　results　showed　that　the　inhibition　kinetics　process　of　Er　(Ⅲ)　on　AOB　bacteria　can　be　better　described　by　subsection　fitting　(0—60mg/L　and　60—120mg/L)　using　Hill　model,　the　R2　obtained　by　fitting　are　0.9909　and　0.9999,　respectively,　and　the　maximum　matrix　removal　rate　qmax　(ΔSNPR)　was　2.59mg/(g·h)　and　7.15mg/(g·h),　respectively.　Long-term　experiments　showed　that　the　performance　of　the　short-cut　nitrification　system　will　gradually　disappear　with　the　addition　of　10mg/L　Er(Ⅲ),　and　the　performance　of　the　reaction　system　could　not　recover　after　the　addition　of　Er(Ⅲ)　was　stopped.　©　2023　Chemical　Industry　Press.　All　rights　reserved.