In　this　manuscript,　Fe(II)　inhibition　of　anammox　and　its　recovery　were　investigated,　and　the　performance,　kinetics　and　statistical　features　were　comprehensively　studied　simultaneously.　Anammox　was　suppressed　and　completely　inhibited　by　the　addition　of　109.29　and　378.57　mg/L　Fe(II),　respectively,　via　uncompetitive　inhibition.　Nitrite　inhibition　of　anammox　was　best　fitted　by　the　Edwards　model　and　Aiba　model.　EDTA-2Na　wash　(0.5,　1.0,　1.5,　and　2.0　mM)　had　a　limited　effect　on　anammox　recovery,　while　the　addition　of　2.0　mM　betaine　accelerated　anammox　recovery.　Prolonged　betaine　addition　caused　an　unintended　reduction　of　anammox　activity,　though　it　self-recovered　after　the　withdrawal　of　betaine.　The　modified　Boltzmann　model　most　accurately　simulated　the　processes　of　anammox　recovery　using　the　EDTA-2Na　wash,　betaine　regulation　and　self-recovery,　and　the　modified　Stover-Kincannon　model　was　able　to　assess　the　results　of　anammox　recovery.　The　one-sample　t-test　was　successfully　applied　to　determine　the　effects　of　these　three　recovery　strategies　on　inhibited　anammox,　which　were　short-term　disinhibition　or　long-term　recovery　effects.　The　above-mentioned　results　demonstrate　that　an　intermittent　addition　of　betaine,　which　is　a　better　alternative　to　frequently-used　but　poorly-degradable　EDTA,　may　be　a　useful　and　environmentally　friendly　recovery　strategy　for　Fe(II)-inhibited　anammox　reactor.　(C)　2020　Elsevier　Ltd.　All　rights　reserved.