In　this　work,　a　novel　integrated　reactor　incorporating　anoxic　fixed　bed　biofilm　reactor　(FBBR),　oxic　moving　bed　biofilm　reactor　(MBBR)　and　settler　sequentially　was　proposed　for　nitrogen　removal　from　rural　domestic　sewage.　For　purposes　of　achieving　high　efficiency,　low　costs　and　easy　maintenance,　biomass　characteristics　and　simultaneous　nitrification-denitrification　(SND)　were　investigated　under　long　sludge　retention　time　during　a　149-day　period.　The　results　showed　that　enhanced　SND　with　proportions　of　37.7-42.2%　tapped　the　reactor　potentials　of　efficiency　and　economy　both,　despite　of　C/N　ratio　of　2.5-4.0　in　influent.　TN　was　removed　averagely　by　69.3%　at　least,　even　under　internal　recycling　ratio　of　200%　and　less　proportions　of　biomass　assimilation　(＜3%).　Consequently,　lower　internal　recycle　and　intermittent　wasted　sludge　discharge　were　feasible　to　save　costs,　together　with　cancellations　of　sludge　return　and　anoxic　stir.　Furthermore,　biomass　with　low　observed　heterotrophic　yields　(0.053　+/-　0.035g　VSS/g　COD)　and　VSS/TSS　ratio　(＜0.55)　in　MBBR,　simplified　wasted　sludge　disposal.　(C)　2012　Elsevier　Ltd.　All　rights　reserved.