A　single-stage　partial　nitrification-anammox　(PN/A)　reactor　treating　low-strength　swage　was　operated　for　288　days　to　investigate　the　recovery　of　nitrogen　removal　from　nitrate　accumulation.　The　reactor　was　quickly　started　up　by　inoculating　anammox　sludge.　However,　nitrite　oxidizing　bacteria　(NOB)　abundance　gradually　increased　on　day　25,　leading　to　high　effluent　nitrate　concentration.　Two　strategies　were　executed　to　control　the　effluent　nitrate.　In　strategy　I,　dissolved　oxygen　(DO)　concentration　was　kept　low　(0.17　+/-　0.08　mg/L),　but　nitrate　production　increased　from　4.71　to　38.18　mg-N/L.　In　strategy　II,　intermittent　aeration　operation　mode　(aeration　7　min/anoxic　21　min)　was　adopted,　which　significantly　lowered　the　nitrate　concentration　to　1.3　mg-N/L,　indicating　the　NOB　was　inhibited.　The　high　nitrogen　removal　rate　of　73　mg-N/(L.d)　was　achieved.　The　evolution　of　bacterial　activity　and　abundance　verified　the　changes　of　the　nitrogen　removal　performance　and　proved　the　intermittent　aeration　strategy　could　successfully　solve　the　problem　of　nitrate　build-up　in　the　PN/A　process.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.