Biological　autotrophic　denitrification　based　on　anaerobic　ammonium　oxidation(ANAMMOX)　has　been　considered　as　the　most　economical　way　in　biological　sewage　treatment　processes　for　nitrogen　removal　presently.　Using　bio-ceramic　filter　with　volcanic　activity,　urban　sewage　pilot　study　was　carried　out　at　room　temperature　(8-25°C)　under　the　condition　of　low　NH4+-N　(60-90　mg　·　L-1),　by　changing　the　operating　conditions　such　as　aeration　etc.　After　three　stages-nitrification　hanging　film,　preferred　nitrite　bacteria　and　culturing　anaerobic　ammonia-oxidizing　bacteria,　CANON(completely　autotrophic　ammonium　removal　over　nitrite)process　is　realized　in　biofilter.　The　results　show　that　DO　control　can　be　the　main　factor　for　controlling　reactor　startup.　Through　combined　treatment　of　aeration　at　the　top　of　water　column　in　biofilter　and　internal　recycling　of　treated　water　with　oxygen,　the　control　of　DO　concentration　in　the　biofilm　system　is　easily　achieved.　Furthermore,　the　reaction　cycle　can　be　judged　from　the　change　of　pH　value　in　the　run　process　and　its　second-jump　is　a　signal　of　end　of　reaction　period.　©　All　Rights　Reserved.