A　lab-scale　sequencing　batch　reactor　(SBR)　was　employed　to　treat　low　C/N　ratio　municipal　wastewater　to　investigate　the　stability　of　nitrification-denitrification　via　nitrite　using　a　real-time　control　strategy　to　switch　aeration　on　and　off.　Three　parameters,　pH,　DO　and　ORP,　were　selected　as　control　parameters　in　the　SBR　reactor　operation.　Nitrite　accumulation　was　observed　under　real-time　control　conditions　(NO2--N/NOx--N　＞　0.8),　implying　that　nitrification-denitrification　mainly　via　nitrite　was　achieved　by　the　process　control　strategy　applied.　The　nitrite　concentration　in　the　SBR　decreased　sharply　when　the　SBR　system　was　operated　using　a　fixed　time　aeration　control　strategy　for　7　days.　Ammonia　nitrogen　concentration　(NH4+-N)　and　temperature　also　affect　nitrite　accumulation.　Ammonia　shock　loads　limited　nitrification　due　to　alkalinity　limitations,　but　the　system　recovered　quickly　from　short-time　high　ammonia　shock　loads　when　the　real-time　control　strategy　was　applied.　Temperature　was　observed　to　affect　nitrite　accumulation　rate　when　the　real-time　control　strategy　was　used　in　the　SBR　reactor,　with　higher　nitrite　accumulation　at　28　±　0.5　°C　(NO2--N/NOx--N　=　0.84),　compared　to　the　accumulation　at　the　ambient　average　temperature　of　20　°C　(NO2--N/NOx--N　＞　0.61).　©　2007.