For　achieving　energy-efficient　wastewater　treatment,　a　novel　simultaneous　nitrogen　and　phosphorus　removal　(SNPR)　process,　which　integrated　anammox,　endogenous　partial-denitrification　and　denitrifying　dephosphatation　in　a　sequencing　batch　reactor　with　granular　sludge　was　developed　to　treat　mainstream　wastewater.　After　200　days　of　operation,　a　simultaneous　high-level　nitrogen　and　phosphorus　removal　of　93.9%　and　94.2%,　respectively　was　achieved　with　an　average　influent　C/N　ratio　of　2.9.　Anammox　pathway　contributed　82.9%　of　the　overall　nitrogen　removal　because　of　the　stable　nitrite　production　from　nitrate　via　endogenous　partial-denitrification.　In　addition,　phosphorus　was　mainly　removed　via　denitrifying　dephosphatation　utilizing　nitrate　as　the　electron　acceptor,　resulting　in　a　significant　saving　of　carbon　sources　and　oxygen　demands.　Further,　adsorption/precipitation　of　phosphorus　occurred　in　this　novel　SNPR　process,　which　displaced　the　energy　source　to　the　metabolism　of　glycogen　accumulating　organisms　(GAOs)　for　nitrite　production　and　alleviated　competition　between　phosphorus　accumulating　organisms　(PAOs)　and　anammox　for　electron　acceptor.　Using　16S　rRNA　gene　amplicon　sequencing　analysis,　the　study　found　that　anammox　bacteria　(8.4%),　GAOs　(1.5%)　and　PAOs　(1.1%)　co-existed　in　this　system,　potentially　resulting　in　simultaneous　endogenous　partial-denitrification,　anammox　and　denitrifying　dephosphatation.　The　above　results　demonstrated　that　the　novel　SNPR　process　is　a　promising　technique　for　energy-efficient　wastewater　treatment.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.