While　direct　anammox　implementation　is　attractive　when　treating　wastewater,　nitrite　(NO2−-N)　availability　and　excess　organic　matter　significantly　limit　its　practical　application.　This　study　proposed　partial　nitrification　and　endogenous　partial　denitrification/anammox　(PN/A-EPD/A)　for　the　treatment　of　real　municipal　wastewater　(COD/N　ratio:　2.8)　within　a　single-stage　reactor　under　anaerobic/aerobic/anoxic　mode.　Interestingly,　with　reducing　dissolved　oxygen　concentration　(5.0　±　1.0　→　1.0　±　0.5　mg-O2/L)　during　aerobic　phase,　Comammox　Nitrospira　clade　A　became　dominated　and　introduced　vast　nitrate　(NO3−-N)　into　the　subsequent　anoxic　stage.　Both　in-situ　and　ex-situ　tests　confirmed　that　sufficient　NO3−-N　as　electron　acceptors　were　in　favor　of　the　EPD/A　occurrence　with　endogenous　organics　utilization,　which　was　obtained　by　anaerobic　endogenous　transformation.　Metagenomic　results　confirmed　the　role　of　Thauera　in　facilitating　NO3−-N→NO2−-N　process,　and　further　supporting　AnAOB.　As　a　result,　Ca.　Brocadia　gradually　enriched　on　granules　(from　0.08%　to　3.51%)　and　contributed　up　to　51.5　%　to　total　inorganic　nitrogen　removal　through　the　PN/A-EPD/A　process.　Optimized　carbon　utilization　pathway　promoted　the　re-cooperative　balance　of　microorganisms　and　this　process　achieved　efficient　nitrogen　removal　(93.5%)　and　desirable　quality　of　effluent　(3.2　mg-N/L)　when　treating　real　municipal　wastewater.　©　2025　Elsevier　Ltd