The　SNAD　(simultaneous　partial　nitrification,　anaerobic　ammonium　oxidization　and　denitrification)　process　was　successfully　developed　in　a　SBR　to　treat　domestic　wastewater.　In　the　beginning,　some　anammox　(anaerobic　ammonium　oxidation)　granules　were　inoculated　into　the　SBR　to　develop　partial　nitrification　granules　under　high　DO　(500　L/h).　Afterwards,　some　anammox　granules　were　added　again　to　develop　SNAD　granules　under　low　DO　(40　L/h).　During　the　stable　partial　nitrification　stage,　the　average　ammonium　removal　rate　was　above　94%　while　the　average　nitrite　accumulation　rate　was　more　than　95%.　In　the　stable　SNAD　stage,　85%　average　total　nitrogen　removal　rate　was　achieved.　To　the　partial　nitrification　granules,　batch　tests　indicated　that　the　specific　aerobic　ammonium　oxidation　activity　and　nitrite　oxidation　activity　were　0.234　and　0　kgN/(kgVSS·d),　respectively.　To　the　SNAD　granules,　batch　tests　indicated　that　the　specific　anammox　activity,　denitrification　activity　over　nitrite,　aerobic　ammonium　oxidation　activity　and　nitrite　oxidation　activity　were　0.158,　0.104,　0.281,　0　kg/(kgVSS·d),　respectively.　The　denitrification　activity　over　nitrate　was　0.061　kg/(kgVSS·d)　during　0~120　min　while　the　value　was　0.104　kg/　(kgVSS·d)　during　120~360　min.　The　SEM　observations　indicated　that　the　bacteria　in　the　outer　part　of　the　SNAD　granule　were　mainly　short　rod-shaped　and　spherical,　which　may　be　AOB　and　denitrification　bacteria.　In　the　inner　part　of　the　SNAD　granule,　the　bacteria　were　mainly　crater-shaped,　which　should　be　anammox　bacteria.　©,　2015,　Zhongguo　Huanjing　Kexue/China　Environmental　Science.　All　right　reserved.