Using　inhibitors　to　selectively　suppress　the　activity　of　nitrite-oxidizing　bacteria　(NOB)　was　an　emerging　way　to　rapidly　achieve　partial　nitrification　(PN).　This　study　explored　the　feasibility　of　inactivating　NOB　by　a　novel　inhibitor　chloroxylenol　(PCMX)　in　real　domestic　wastewater.　Different　frequencies　(periodic　strategy　and　concentrative　time　strategy)　of　PCMX　side-stream　sludge　treatment　were　used　to　achieve　and　maintain　PN　during　250　days.　PN　was　realized　by　PCMX　treatment　once　a　day　about　20　days,　due　to　the　inhibition　of　Nitrospira.　PN　was　completely　destroyed　after　212　days　by　periodic　strategy,　caused　by　the　increase　of　Candidatus　Nitrotoga.　PN　maintained　without　PCMX　in　following　201　days　by　concentrative　time　strategy.　The　risks　of　PCMX　were　assessed　and　almost　no　PCMX　was　detected　in　the　effluent　of　mainstream　sequencing　batch　reactors.　These　results　meant　PN　realized　by　PCMX　side-stream　sludge　treatment　was　feasible　and　concentrative　time　strategy　was　a　better　operating　strategy.