Nitrate　or　nitrite-dependent　anaerobic　methane　oxidation　(n-DAMO)　is　a　microbial　process　that　links　carbon　and　nitrogen　cycles　as　a　methane　sink　in　many　natural　environments.　This　study　demonstrates,　for　the　first　time,　that　the　nitrite-dependent　anaerobic　methane　oxidation　(nitrite-DAMO)　process　can　be　stimulated　in　sewer　systems　under　continuous　nitrate　dosing　for　sulfide　control.　In　a　laboratory　sewer　system,　continuous　nitrate　dosing　not　only　achieved　complete　sulfide　removal,　but　also　significantly　decreased　dissolved　methane　concentration　by　similar　to　50　%.　Independent　batch　tests　confirmed　the　coupling　of　methane　oxidation　with　nitrate　and　nitrite　reduction,　revealing　similar　methane　oxidation　rates　of　3.68　+/-　0.5　mg　CH4　L-1　h(-1)　(with　nitrate　as　electron　acceptor)　and　3.57　+/-　0.4　mg　CH4　L-1　h(-1)　(with　nitrite　as　electron　acceptor).　Comprehensive　microbial　analysis　unveiled　the　presence　of　a　subgroup　of　the　NC10　phylum,　namely　Candidatus　Methylomirabilis　(n-DAMO　bacteria　that　couples　nitrite　reduction　with　methane　oxidation),　growing　in　sewer　biofilms　and　surface　sediments　with　relative　abundances　of　1.9　%　and　1.6　%,　respectively.　In　contrast,　n-DAMO　archaea　that　couple　methane　oxidation　solely　to　nitrate　reduction　were　not　detected.　Together　these　results　indicated　the　successful　enrichment　of　n-DAMO　bacteria　in　sewerage　systems,　contributing　to　approx.　64　%　of　nitrite　reduction　and　around　50　%　of　dissolved　methane　removal　through　the　nitrite-DAMO　process,　as　estimated　by　mass　balance　analysis.　The　occurrence　of　the　nitrite-DAMO　process　in　sewer　systems　opens　a　new　path　to　sewer　methane　emissions.