In　this　study,　a　full-scale　partial　nitritation/anammox　(PN/A)　process　was　successfully　established　to　treat　dewatering　liquor　(filtrate)　from　the　activated　sludge　after　thermal　hydrolysis　(THP)　-　anaerobic　digestion　(AD).　The　filtrate　had　an　average　ammonium　of　1407　mg/L　with　a　COD/N　ratio　of　1.43　+/-　0.3.　Under　limited　anammox　biofilm　inoculation,　PN/A　was　started-up　in　an　integrated　fixed　-　biofilm　activated　sludge　(IFAS)　reactor.　During　the　stable　period,　2500　m(3)　of　THP　-　AD　sludge　filtrate　was　treated　daily　and　an　average　nitrogen　removal　rate　of　0.21　kg　N/(m(3).d)　was　maintained　with　a　removal　efficiency　over　85%.　The　application　of　PN/A　reduced　mainstream　total　inorganic　nitrogen　in　effluent　by　4.4　mg/L,　saving　$3.5　million　in　operational　costs　annually　due　to　the　reduction　of　organics　addition.　Overall,　IFAS　-　PN/A　process　can　be　an　efficient　and　economical　method　to　treat　THP　-　AD　sludge　filtrate　and　improve　mainstream　nitrogen　removal　performance.