Applying　anammox　to　municipal　wastewater　treatment　promises　enormous　energy　and　resource　savings;　however,　seasonally　cold　conditions　pose　a　considerable　challenge,　impeding　its　future　applications　towards　non-tropical　regions.　In　this　study,　we　establish　a　pilot-scale　wastewater　treatment　plant　(50　m3/d)　in　northern　China　and　implement　the　partial　denitrification　coupling　anammox　process　on　actual　municipal　wastewater.　Despite　seasonal　cooling,　the　nitrogen　removal　efficiency　remains　high,　ranging　from　75.0　+/-　4.6%　at　27.8-20.0　degrees　C　to　70.4　+/-　4.5%　at　10-7.5　degrees　C.　This　process　exhibits　remarkable　low-temperature　tolerance,　achieving　an　in-situ　anammox　rate　of　32.7　+/-　4.7　g-N/(m3d)　at　10-7.5　degrees　C　and　contributing　up　to　39.7　+/-　6.7%　to　nitrogen　removal.　Further　15N　stable　isotope　tracing　and　kinetic　tests　reveal　that　the　partial　denitrification　is　capable　of　supplying　increasingly　abundant　NO2-　to　anammox　with　decreasing　temperature,　enabling　robust　mainstream　anammox　against　seasonal　cooling.　From　27.8　degrees　C　to　7.5　degrees　C,　anammox　bacteria　not　only　survive　but　thrive　under　mainstream　conditions,　with　absolute　and　relative　abundances　increasing　by　429.1%　and　343.5%,　respectively.　This　pilot-scale　study　sheds　fresh　light　on　extending　mainstream　anammox　towards　non-tropical　regions,　taking　a　necessary　step　forward　toward　the　sustainability　goals　of　the　wastewater　treatment　sector.　Low　temperatures　pose　challenges　to　applying　sustainable　anammox　technology　in　non-tropical　regions.　Here,　authors　propose　a　partial　denitrification　coupling　anammox　process　and　conduct　a　pilot-scale　evaluation,　offering　insights　into　extending　anammox　applications　to　colder　locations.