To　realize　the　purpose　of　enhanced　nitrogen　removal　(TN　-1)　in　step　feed　process　treating　urban　wastewater,　by　using　SBR　reactor,　the　nitrite　accumulation,　variation　of　pH　and　ORP　as　well　as　dynamic　properties　during　denitrification　with　methanol　and　glucose　as　the　sole　carbon　sources　are　investigated　in　details.　The　results　show　that　for　both　carbon　sources,　serious　nitrite　accumulations　are　observed　during　denitrification　under　different　ratios　of　nitrogen　and　carbon　(C/N).　With　identical　C/N,　when　glucose　is　used　as　carbon　source　there　is　more　maximum　NO2--N　accumulation　concentration.　However,　NO3--N　reduction　rate　is　faster　than　NO2--N　reduction　rate　for　both　carbon　sources.　Furthermore,　with　the　increase　of　C/N,　the　maximum　NO2--N　concentration　increases　and　the　time　in　which　the　NO2--N　achieves　the　highest　concentration　is　accordingly　shortened.　For　glucose,　however,　under　high　C/N　ratio　(C/N　=　29.3)　both　the　denitrification　rate　and　NO2--N　accumulation　concentration　decrease.　Besides,　the　changes　of　pH　and　ORP　reflect　the　variation　of　NO2--N　accumulation　concentration　well　because　pH　and　ORP　have　the　significant　relationship　with　NO2--N　concentration.　The　second　inflexion　on　curves　indicates　the　real　end　of　denitrification　process.