Anaerobic　ammonium-oxidizing　(anammox)　process　is　considered　to　be　a　sustainable　option　for　nitrogen　removal.　Application　of　this　process,　however,　is　limited　by　the　availability　of　high　strength　nitrogen.　In　this　study,　an　anaerobic　ammonium　oxidation　(ANAMMOX)　biofilter　to　treat　sewage　was　deployed　at　ambient　temperatures　(18-21.5　degrees　C),　and　the　corresponding　microbial　community　was　investigated.　The　ammonia　and　nitrite　initial　loading　rates　were　0.154　kgN/(m(3)　d)　and　0.2　kgN/(m(3)　d),　respectively.　ANAMMOX　bacteria　were　rapidly　enriched　within　25　days　and　achieved　a　sustainable　increase　in　the　nitrogen　removal　rate　(NRR)　for　sewage　treatment.　A　final　NRR　of　0.99　kgN/(m(3)　d)　was　seen　at　the　80　day　point.　Observations　that　combined　fluorescence　in　situ　hybridization　(FISH)　analysis　with　scanning　electron　microscopy　(SEM)　observations　confirmed　that　ANAMMOX　bacteria　were　dominant　in　the　cultivated　biofilm,　accounting　for　39.5　(+/-　1.6)%　of　total　bacteria.　Denaturing　gradient　gel　electrophoresis　(DGGE)　and　phylogenetic　analysis　identified　five　genera　of　bacteria:　Pseudomonas,　Acinetobacter,　Nitrosomonas,　Candidatus　Brocadia　fulgida　and　Ferruginibacter.　Of　these,　Candidatus　Brocadia　fulgida　was　the　functional　ANAMMOX　bacteria　in　the　reactor.　Candidatus　Brocadia　fulgida　could　survive　comfortably　in　sewage,　and　co-existed　with　Nitrosomonas　and　denitrifying　bacteria.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.