Efficient　retention　and　enrichment　of　anammox　bacteria　(AnAOB)　are　essential　for　the　application　of　municipal　wastewater　anammox.　Herein,　an　innovative　process　for　highly　enriching　AnAOB　within　suspended　carrier　was　developed　in　a　single-stage　anaerobic/oxic/anoxic　reactor　with　5.5　%　carrier　filling　ratio　for　real　sewage.　Addition　of　sludge　fermentation　products　promoted　stable　maintenance　of　partial　nitrification　(nitrite　accumulation　rate　＞　90.0　%)　and　achieved　efficient　external　sludge　reduction　(27.6-37.9　%).　Continuous　nitrite　supply　and　carrier　addition　promoted　AnAOB　enrichment　(2.4　x　1011　gene　copies/g　dry　sludge).　Candidatus　Brocadia　was　the　predominant　bacteria　in　carriers　(18.6　%).　The　average　effluents　of　total　inorganic　nitrogen　(TIN)　and　NH4+-N　were　1.9　and　0.8　mg/L　with　removal　rates　of　97.0　%　and　98.7　%.　In　the　anoxic　stage,　TIN　removal　rate　reached　71.5　%,　and　the　proportion　of　anammox　to　nitrogen　removal　accounted　for　82.7　%.　This　study　broadens　the　application　of　mainstream　sewage　anammox　and　the　resource　utilization　of　waste　activated　sludge.