The　studies　of　partial　nitrification　and　anaerobic　ammonium　oxidation　(anammox)　mainly　focus　on　high　ammoniacal　concentration　effiuents.　A　few　research　about　domestic　sewage　of　low　ammonia　nitrogen　concentration　was　reported.　The　domestic　sewage　was　pumped　into　the　UASB　reactor　after　carbon　removal　and　partial　nitrification　to　explore　the　impact　of　domestic　sewage　on　mature　anammox　granular　sludge.　The　results　showed　that　the　concentrations　of　NH4+-N　and　NO2--N　in　effluent　were　below　5　mg·L-1　and　1　mg·L-1,　respectively　when　the　inflow　became　domestic　sewage.　But　the　NO3--N　concentration　was　higher　than　the　theoretical　value　because　the　increased　dissolved　oxygen　enhanced　nitrification.　The　color　of　anammox　sludge　in　UASB　reactor　changed　from　light　red　to　dark　red.　The　T-EPS　content　of　sludge　decreased　and　the　PN/PS　value　increased　from　1.13　to　3.66.　The　settleability　of　the　sludge　turned　better.　The　percentage　of　Candidatus　Brocadia　bacteria　in　the　sludge　decreased　from　17.7%　to　14.4%.　The　ammonia-oxidizing　bacteria　and　nitrite-oxidizing　bacteria　contents　in　the　sludge　increased.　If　dissolved　oxygen　into　the　UASB　reactor　can　be　reduced,　the　NO3--N　concentration　in　effluent　may　decrease　and　total　nitrogen　removal　efficiency　may　be　higher.　©　All　Right　Reserved.