Poly-phosphate　accumulating　organisms　(PAOs)　could　use　nitrite　as　electron　acceptor　but　poorly　function　compared　to　oxygen　in　phosphorus　removal.　The　authors　try　to　figure　out　the　different　effects　on　anoxic　and　aerobic　P-uptake　by　environmental　factors　(pH,　temperature　and　nitrite　concentration)　and　identify　the　real　inhibitor　in　anoxic　metabolisms.　26　sets　of　batch　tests　were　designed,　using　highly　concentrated　PAO　cultures.　The　results　show　pH　influence　on　P-uptake　activity　are　similar　in　anoxic　and　aerobic　tests,　but　temperature　has　strong　effects　on　aerobic　P-uptake　activity　compared　to　anoxic.　pH　values　were　are　correlated　linearly　with　nitrite　reduction　and　P-uptake　rates　instead　of　FNA.　Also,　weak　correlation　between　FNA　and　two　reaction　rates　shows　pH　rather　than　FNA　is　likely　the　main　inhibitor.　P-uptake　rates　are　correlated　linearly　with　nitrite　reduction　and　PHA　consumption　rates.　It＇s　possible　that　intracellar　NO-　2　concentration　isn＇t　affected　by　FNA　diffusion　and　don＇t　affect　intracellar　P-uptake　process.　©　(2014)　Trans　Tech　Publications,　Switzerland.