This　study　presented　a　novel　process　for　simultaneous　biological　nutrient　removal　and　waste　activated　sludge　reduction　in　one-stage　municipal　wastewater　treating　system　without　aeration　on　the　basis　of　endogenous　partial　denitrification,　anammox　and　Candidatus　Phosphoribacter　dominated　biological　phosphate　removal　with　sludge　reduction　(EPDA/PSR).　The　effluent　total　inorganic　nitrogen　and　phosphate　concentrations　were　0.1　mg/L　and　lower　than　detection　limit　(0.1　mg/L),　respectively,　without　dosing　external　carbon　sources.　Compared　with　partial　denitrification-anammox　process,　the　daily　sludge　production　in　EPDA/PSR　process　reduced　by　50.8　%.　The　percentage　of　intact　cells　measured　by　flow　cytometry　reduced　from　92.4　%　to　77.3　%　with　the　increase　of　aromatic　protein,　DNA　content　of　supernatant,　soluble　microbial　byproduct-like　substance　and　decline　of　particle　size.　The　sludge　stabilization　structure　was　destructed,　and　intracellular　organics　were　released,　which　resulted　in　the　reduction　of　sludge　production.　Microbial　community　structure　at　transcriptional　level　indicated　that　really　working　Candidatus　Phosphoribacter　(phosphorus　accumulating　organisms　with　fermentation　capacity),　Candidatus　Competibacter　(endogenous　partial　denitrification　bacteria)　and　Candidatus　Brocadia　(anammox　bacteria)　reached　68.4　%,　9.84　%　and　8.02　%,　respectively,　and　Candidatus　Kuenenia　(anammox　bacteria)　did　not　play　a　role　in　EPDA/PSR　system.　The　novel　one-stage　EPDA/PSR　process　realized　high　efficient　biological　nutrient　removal,　achieved　waste　activated　sludge　reduction　and　saved　100　%　of　aeration　energy　consumption　cost　and　external　carbon　source　dosage　cost,　which　effectively　developed　internal　carbon　source　and　provided　a　new　idea　for　wastewater　treatment.