The　biological　nitrogen　removal　of　municipal　wastewater　was　successfully　improved　by　integrating　anammox　in　a　step-feed　sequencing　biofilm　batch　reactor.　Despite　fluctuating　influent　carbon　to　nitrogen　ratio　(1.9–5.1)　and　decreasing　temperature　(24.1–16.3　℃),　nitrogen　removal　efficiency　of　95.9　±　1.4　%　and　nitrogen　removal　rate　of　0.23　±　0.02　kg　N/(m3·d)　were　successfully　maintained　without　requirement　of　external　carbon　sources.　The　advanced　removal　performance　was　mainly　attributed　to　the　enhanced　anammox.　Anammox　bacteria　presented　a　high　relative　abundance　(42.9%　in　biofilms,　1.5%　in　flocs)　and　anammox　activity　was　as　high　as　5.42　±　0.12　mg　N/(g　volatile　suspended　solids·h).　Further　analysis　suggested　that　flexible　control　of　influent　organic　and　ammonium　through　step-feeding　could　provide　multiple　substrate　supply　for　anammox　reaction,　potentially　resulting　in　stable　combination　of　anammox　with　hybrid-nitrite-shunt　processes.　Overall,　this　study　provides　a　promising　anammox-related　application　with　simple-control　step-feed　strategy　for　enhanced　and　stable　nitrogen　removal　from　carbon-limited　municipal　wastewater.　©　2023　Elsevier　Ltd