Low　water　temperatures　and　ammonium　concentrations　pose　challenges　for　anammox　applications　in　the　treatment　of　low　C/N　municipal　wastewater.　In　this　study,　a　10　L　-water　bath　sequencing　batch　reactor　combing　biofilm　and　suspended　sludge　was　designed　for　low　C/N　municipal　wastewater　treatment.　The　nitrogen　removal　performance　via　partial　nitrification　anammox-(endogenous)　denitrification　anammox　process　was　investigated　with　anaerobic　-aerobic　-anoxic　mode　at　low　temperatures　and　dissolved　oxygen　(DO).　The　results　showed　that　with　the　decrease　of　temperature　from　30　to　15　degrees　C,　the　influent　and　effluent　nitrogen　concentrations　and　nitrogen　removal　efficiencies　were　73.7　+/-　6.5　mg/L,　7.8　+/-　2.8　mg/L,　and　89.4　%,　respectively,　with　aerobic　hydraulic　retention　time　of　only　6　h　and　DO　concentration　of　0.2-0.5　mg/L.　Among　that,　the　stable　anammox　process　compensated　for　the　inhibitory　effects　of　the　low　temperatures　on　the　nitrification　and　denitrification　processes.　Notably,　from　30　to　15　degrees　C,　the　anammox　activity　and　relative　abundance　of　the　dominant　Brocadia　genus　were　increased　from　39.7　to　45.5　mgN/gVSS/d　and　7.3　to　12.0　%,　respectively;　the　single　gene　expression　level　of　the　biofilm　increased　9.0　times.　The　anammox　bacteria　showed　a　good　adaptation　to　temperatures　reduction.　However,　nitrogen　removal　by　anammox　was　not　improved　by　increasing　DO　(＞=　4　mg/L)　at　8-4　degrees　C.　Overall,　the　results　of　this　study　demonstrate　the　feasibility　of　the　mainstream　anammox　process　at　low　temperatures.