The　anaerobic　ammonium　oxidation　(anammox)　process　is　a　promising　method　for　carbon　reduction　and　energy　conservation.　However,　the　advantages　of　its　application　in　municipal　wastewater　treatment　have　not　been　completely　revealed.　Stable　nitrogen　removal　was　successfully　achieved　in　the　anaerobic/aerobic/anoxic　(AOA)　process　by　directly　integrating　stable　anammox.　Over　a　200　+　day　operating　period,　the　abundance　of　anammox　bacteria　(3.1　±　0.9　×　108　copies/gSS)　and　anammox　activity　(0.32　±　0.07　mgN/(gSS·h))　remained　high,　despite　a　temperature　decrease　(27.8–17.2　°C)　and　fluctuating　carbon-nitrogen　(C/N)　ratio　(1.6–5.0).　A　stable　nitrogen　removal　efficiency　of　87.1　±　2.5　%　was　successfully　maintained,　because　the　anammox　activity　compensated　for　the　effect　of　low　temperatures　and　low　C/N　ratios　on　the　nitrification　and　denitrification.　Further　analysis　found　that　anammox　accounted　for　52.6　%-57.5　%　of　N2　production,　and　the　rest　was　through　nitrification–denitrification.　The　stable　anammox　reaction　was　mainly　due　to　the　limitation　of　oxygen　and　carbon　sources　and　the　stable　supply　of　nitrite　by　endogenous　denitrification.　Overall,　these　findings　confirmed　that　the　stability　and　efficiency　of　nitrogen　removal　from　municipal　wastewater　could　be　increased　by　integrating　anammox　under　appropriate　conditions.　©　2022　Elsevier　B.V.