Anoxic　MBBR　is　a　process　to　achieve　advanced　denitrification　from　municipal　wastewater.　Here,　anoxic　MBBR　was　applied　as　a　post-denitrification　SBR　to　achieve　advanced　denitrification　by　partial　anammox　(anaerobic　ammonium　oxidation).　During　a　250-day　operation,　denitrification　performance　gradually　improved　and　the　total　nitrogen　concentration　of　the　effluent　was　approximately　5　mg•L-1.　The　average　nitrate,　ammonia,　and　total　inorganic　nitrogen　removal　efficiencies　were　(97.7±2.9)%,　(93.3±2.9)%,　and　(94.3±2.7)%,　respectively,　between　day　211　and　250.　The　simultaneous　removal　of　ammonia　and　nitrate　was　observed　in　the　anoxic　reactor.　Analysis　of　the　ammonia　removal　pathway　revealed　that　assimilation　and　nitrification　were　poor　in　the　anoxic　MBBR.　The　anammox　activity　test　and　the　denitrification　performance　showed　that　anammox　occurred　and　played　a　not　insignificant　role　in　the　anoxic　MBBR.　The　results　of　real-time　quantitative　PCR　showed　that　anammox　bacteria　enriched　in　anoxic　MBBR,　especially　in　the　anoxic　carrier　biofilms,　where　the　abundance　of　anammox　bacteria　increased　from　4.37×107　copies•g-1　to　2.28×1010　copies•g-1.　This　study　demonstrates　that　anoxic　carrier　biofilms　may　have　potential　applications　in　anammox　bacterial　enrichment　to　enhance　denitrification　from　municipal　wastewater.　©　2019,　Science　Press.　All　right　reserved.