Anovelfixed-bed　biofilm　process　based　on　partial　denitrification/anammox　(PD/A)　was　developed　for　the　simultaneous　treatment　of　low　C/N　domestic　wastewater　and　secondary　effluent.　The　nitrogen　removal　performance　of　the　process　at　different　influent　C/N　(1.3,　1.5,　1.6,　1.8)　and　different　pH　(7.5,　8.0,　8.5,　9.0)　was　studied.　Results　showed　that　increasing　influent　C/N　enhanced　the　complete　denitrification　of　the　system,　whichincreased　the　average　removal　rate　of　NO3--N　from　52.3%　to　85.7%;　The　higher　influent　pH　promoted　theNO2--N　accumulation　in　partial-denitrification　process,　and　then　enhanced　the　autotrophic　nitrogen　removal　by　the　anammox,　which　increased　the　average　removal　rate　of　NH4+-N　from　82.2%　to　89.7%.　Under　the　conditions　of　C/N=1.6　and　pH=9.0,　88.3%　of　TN　removal　rate　was　achieved,　and　the　effluent　TN　was　stable　less　than　2mg/L.　Moreover,　the　potential　of　the　fixed-bed　biofilm　process　based　on　PD/Ain　the　upgrading　of　traditional　AAO　process　was　analyzed.　©　2020,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.