The　two-sludge　anoxic　dephosphation　(DEPHANOX)　process　frequently　encounters　the　challenge　of　elevated　effluent　ammonia　levels　in　practical　applications.　In　this　study,　the　anaerobic　ammonium　oxidation　(anammox)　biofilm　was　introduced　into　the　DEPHANOX　system,　transforming　it　into　a　three-sludge　system,　enabling　synchronous　nitrogen　and　phosphorus　elimination,　particularly　targeting　ammonia.　Despite　a　chemical　oxygen　demand/total　nitrogen　ratio　of　4.3　±　0.8　in　the　actual　municipal　wastewater　and　4.5　h　of　aeration,　the　effluent　total　nitrogen　was　13.7　mg/L,　lower　than　the　parallel　wastewater　treatment　plant.　Additionally,　the　effluent　ammonia　reduced　to　5.1　±　2.5　mg/L.　Notably,　denitrifying　phosphorus　removal　and　anammox　were　coupled　in　the　anoxic　zone,　yielding　74.5　%　nitrogen　and　87.8　%　phosphorus　removal.　16S　rRNA　gene　sequencing　identified　denitrifying　phosphorus-accumulating　organisms　primarily　in　floc　sludge　(Saprospiraceae　7.07　%,　Anaerolineaceae　1.95　%,　Tetrasphaera　1.57　%),　while　anammox　bacteria　inhabited　the　biofilm　(Candidatus　Brocadia　4.00　%).　This　study　presents　a　novel　process　for　efficiently　treating　municipal　wastewater.　©　2024　Elsevier　Ltd