Anammox-based　processes　are　pivotal　for　elevating　nitrogen　removal　efficiency　in　municipal　wastewater　treatment.　This　study　established　a　novel　HF-EPDA　system　combined　in-situ　hydrolytic　fermentation　(HF)　with　endogenous　partial　denitrification　(EPD)　and　anammox.　Slowly-biodegradable　organic　matter　(SBOM)　was　degraded　and　transformed　into　endogenous　polymers　for　driving　production　of　sufficient　nitrite　by　EPD,　further　promoted　the　nitrogen　removal　via　anammox　process.　Processes　above　formed　positive　feedback,　guaranteeing　the　robustness　and　recoverability　of　system.　After　a　92-day　suspension　during　operation,　advanced　nitrogen　removal　was　still　achieved　with　excellent　nitrogen　removal　efficiency　of　95.84　+/-　1.73　%,　treating　with　actual　domestic　wastewater　and　synthetic　nitrate　wastewater.　Candidatus　Brocadia　and　Candidatus　Competibacter　were　dominant　bacteria　on　biofilms　responsible　for　the　anammox　and　EPD　process　respectively,　while　the　main　hydrolytic　fermentation　organisms　norank_o　SBR1031　was　enriched　in　floc　sludge.　This　study　highlights　the　reliable　potential　for　expanding　anammox　application　with　simultaneous　improvement　of　SBOM　utilization.