A　bench-scale　reactor(72　L)　red　with　domestic　sewage,　was　operated　more　than　3　months　with　three　operation　modes:　traditional　mode,　modified　mode　and　real-time　control　mode,　so　as　to　evaluate　effects　of　the　operation　mode　on　the　system　performance　and　to　develop　a　feasible　control　strategy.　Results　obtained　from　fixed-time　control　study　indicate　that　the　variations　of　the　pH　and　oxidation-reduction　potential(ORP)　profiles　can　represent　dynamic　characteristics　of　system　and　the　cycle　sequences　can　be　controlled　and　optimized　by　the　control　points　on　the　pH　and　ORP　profiles.　A　control　strategy　was,　therefore,　developed　and　applied　to　real-time　control　mode.　Compared　with　traditional　mode,　the　total　nitrogen(TN)　removal　can　be　increased　by　approximately　16%　in　modified　mode　and　a　mean　TN　removal　of　92%　was　achieved　in　real-time　control　mode.　Moreover,　approximately　12.5%　aeration　energy　was　saved　in　realtime　control　mode.　The　result　of　this　study　shows　that　the　performance　of　nitrogen　removal　was　enhanced　in　modified　operation　mode.　Moreover,　the　real-time　control　made　it　possible　to　optimize　process　operation　and　save　aeration　energy.