The　application　of　partial　nitritation-anammox　(PNA)　process　suffers　severe　obstacles　due　to　the　instability　of　partial　nitritation　(PN)　process.　This　study　sought　to　evaluate　the　feasibility　of　endogenous　partial　denitratation　(EPD)　as　a　remediation　or　alternative　to　supply　nitrite　for　the　unstable　PNA　process.　A　novel　strategy　of　optimal　organics　utilization　through　pre-anaerobic　carbon　storage　and　post-anoxic　endogenous　denitrification　coupled　with　anammox　was　developed　in　a　single-stage　bioreactor　treating　actual　municipal　wastewater　with　low　C/N　(similar　to　3.2).　Specifically,　the　undesired　NO2-/NH4+　ratio　(2.4　to　0.04)　and　nitrate　accumulation　were　obtained　by　increasing　the　aeration　rate　(0.6　to　1.8　L/min)　to　simulate　the　PN　instability.　Delightedly,　advanced　nitrogen　removal　efficiency　(92.1%)　was　maintained　despite　a　dramatic　decrease　in　nitrite　accumulation　ratio　from　97.6%　to　2.6%.　This　was　attributed　to　the　significant　increase　in　anammox　contribution　to　total　nitrogen　removal　from　30.2%　to　80.5%.　The　steady　nitrite　flux　supplied　from　EPD　coupled　with　PN　(EPD　contribution　increased　from　0　to　97.0%)　was　assumed　to　be　the　main　reason　for　the　continually　increasing　abundance　and　bioactivity　of　anammox　bacteria.　Both　the　anammox　bacteria　(1.5%,　Ca.　Brocadia)　and　glycogen　accumulating　organisms　(6.0%,　responsible　for　EPD)　were　enriched　and　coexisted　stably　in　the　single　reactor.　Our　study　confirms　that　coupling　EPD　with　anammox　has　great　potential　as　a　remediation　for　the　unstable　mainstream　PNA　process.