A　bench-scale　anaerobic-anoxic-oxic　(A(2)O)　bioreactor　with　steady　denitrifying　phosphorus　removal　performance　was　tested　to　determine　the　influence　of　influent　C/N　ratio　(SCOD/TN)　and　C/P　ratio　(SCOD/　TP)　on　biological　nutrient　removal　for　treating　synthetic　brewage　wastewater;　meanwhile,　the　spatial　profiles　of　DO　pH　and　ORP　sensors　in　such　systems　were　investigated.　The　results　showed　that　influent　C/N　ratio　had　significant　effect　on　the　TN,　TP　removal　efficiencies　and　the　ratio　of　anoxic　to　aerobic　P　uptake　amount.　The　maximal　TN　and　TP　removal　efficiencies　could　be　achieved　when　influent　C/N　ratio　was　kept　at　about　7.1　and　5,　respectively.　Besides,　the　ratio　of　anoxic　to　aerobic　P　uptake　amount　was　found　to　be　linearly　dependent　on　the　influent　C/N　ratio　with　coefficient　R-2　of　0.685　when　total　recirculation　ratio　was　constant　at　3.5.　Influent　C/P　ratio　had　an　important　effect　on　the　TP　removal　efficiency,　while　it　hardly　affected　TN　removal　efficiency.　In　addition,　the　TP　removal　efficiency　reached　the　maximum　for　influent　C/P　ratio　of　42.　On　the　other　hand,　it　was　also　found　that　the　typical　profiles　of　DO,　pH　and　ORP　sensors　could　be　observed,　and　they　have　similar　trends　at　the　different　influent　C/N　ratio　and　C/P　ratio.　It　was　suggested　that　the　operational　state　could　be　well　known　according　to　the　changes　of　simple　online　sensors.