This　study　developed　a　novel　strategy　for　rapidly　achieving　partial　nitrification　(PN)　without　additional　chemical　agents,　and　infrastructure　costs,　only　by　controlling　aeration　time　to　selectively　enrich　ammonium　oxidizing　bacteria　(AOB)　after　simultaneously　eliminating　AOB　and　nitrite　oxidizing　bacteria　(NOB).　Shorter　aeration　time　and　sludge　retention　time　(10 days)　were　implemented　to　simultaneously　eliminate　AOB　and　NOB,　the　bioactivities　drastically　decreased　to　13　and　0%,　respectively.　Subsequently,　a　gradually　prolonged　aeration　time　selectively　enriched　AOB　and　resulted　in　PN.　The　amoA　abundances　increased　to　1.9 × 1010 copies gVSS-1,　whereas　Nitrospira　and　Nitrobacter　abundances　remained　stable　(3.2 × 109　and　3.1 × 109 copies gVSS-1).　A　nitrite　accumulation　rate　above　96%　was　achieved　and　maintained　for　205 days　over　the　entire　temperature　range　(28.5-17.9 °C).　The　effluent　contained　1.9 mg N L-1　of　ammonium,　25.3 mg N L-1　of　nitrite,　and　less　than　1.0 mg N L-1　of　nitrate,　facilitating　mainstream　wastewater　anammox.