A　novel　process　that　combines　partial　nitrification,　fermentation　and　Anammox-partial　denitrification　(NFAD)　was　proposed　to　co-treat　ammonia　rich　sludge　supernatant　(NH4+-N　=　1194.1　mg/L),　external　WAS　(MLSS　=　22092.6　mg/L)　and　WWTP　secondary　effluent　(NO3--N　=　58.6　mg/L).　Three　separated　reactors　were　used　for　partial　nitrification　(PN-SBR),　integrated　fermentation　and　denitrification　(IFD-SBR)　and　combined　Anammox-partial　denitrification　(AD-UASB),　respectively.　The　process　resulted　in　excellent　nitrogen　removal　efficiency　(NRE)　of　98.7%,　external　sludge　reduction　efficiency　(SRE)　of　44.6%　and　external　sludge　reduction　rate　of　4.1　kg/m3　after　200　days　of　continuous　operation.　IFD-SBR　and　AD-UASB　contributed　towards　89.4%　and　9.2%　nitrogen　removal,　respectively.　In　AD-UASB,　cooperation　between　Anammox　bacteria　(4.1%　Candidatus　Brocadia)　and　partial　denitrifying　bacteria　(3.2%　Thauera)　resulted　in　significant　stability　of　Anammox　pathway,　which　contributed　up　to　84.1%　nitrogen　removal　in　the　combined　Anammox-partial　denitrification　process.　NFAD　saved　up　to　100%　organic　resource　demand　and　25%　of　aeration　consumption　compared　with　the　traditional　nitrification-denitrification　process.