Advanced　nitrogen　and　phosphorus　removal　in　a　single-stage　suspending-sludge　system　was　achieved　by　employing　a　novel　Anaerobic/Oxic/Anoxic　(AOA)　strategy　over　200 days.　Satisfactory　total　inorganic　nitrogen　(TIN)　removal　efficiency　of　90.4%　was　achieved　and　effluent　phosphorus　was　below　0.5 mg/L　when　treating　domestic　wastewater　with　the　chemical　oxygen　demand　(COD)/TIN　as　low　as　2.98 ± 1.26.　Stable　nitritation　was　maintained　with　the　ammonia　residual　and　low　dissolved　oxygen　of　0.2-0.5 mg/L　at　aerobic　stage　following　by　a　post　anoxic　stage.　The　much　higher　activity　of　ammonia　oxidation　bacteria　(12.99　mgN/gVSS/h)　was　achieved　than　the　nitrite　oxidation　bacteria　(0.09　mgN/gVSS/h).　Notably,　improved　anammox　performance　was　obtained　without　initial　inoculation,　contributing　47.4%　to　TIN　removal.　The　abundance　of　Nitrosomonas　increased　from　0.12%　to　0.95%　(P ＜ 0.001)　and　self-enrichment　of　anammox　bacteria　Ca.　Brocadia　was　confirmed.　It　provided　new　insight　into　the　advanced　nutrient　removal　with　comprehensible　regulation　and　less　aeration　requirement.