The　feasibility　of　obtaining　and　keeping　stable　nitrite　accumulation　in　Sequencing　Batch　Reactors　(SBRs)　treating　domestic　wastewater　is　studied.　The　final　product　of　ammonium　oxidation　is　either　reproducible　nitrate　or　nitrite　depending　on　the　aeration　strategy.　With　the　aerobic-anoxic　sequence,　two　SBRs　fed　with　domestic　wastewater　are　operated　in　parallel.　One　SBR　(SBR1)　is　controlled　by　the　aeration　control　strategy,　and　the　other　SBR　(SBR2)　by　alternate　aeration　control　strategy.　Based　on　the　on-fine　indirect　measurements　of　DO　and　pH,　the　relationship　between　pH　(or　DO)　and　nitrogen　concentration　(NH4+-N,　NO3--N　and　NO2--N)　is　investigated.　The　result　indicates　that　pH　and　DO　can　be　used　as　control　parameters　for　the　real-time　aeration　control　strategy　to　obtain　nitritation　in　SBR　treating　domestic　wastewater.　The　result　of　SBR1　indicates　that　long-term　stable　nitritation　is　possible　at　32　+/-　1degreesC.　The　result　of　SBR2　indicates　that　the　aeration　control　strategy　is　necessary　for　nitritation　during　the　acclimation　period,　because　the　nitrite　accumulation　disappears　when　the　aeration　is　extended.