Start-up strategy and bacterial community analysis of SNAD process for treating anaerobic digester liquor of swine wastewater (ADLSW) in a continuous-flow biofilm reactor

Simultaneous partial nitrification, anammox and denitrification (SNAD) process for treating anaerobic digester liquor of swine wastewater (ADLSW) was achieved successfully in a continuous -flow biofilm reactor by gradually increasing the influent ammonium ( NH4+-N ) concentration whilst controlling the low dissolved oxygen (DO) concentration. After 180 days of operation, the average removal efficiencies of NH4+-N , total nitrogen (TN) and COD were 61.59, 55.76 and 75.21% respectively. Also, the average conversion efficiency mml:mfenced close=")" open="(" separators=""Ymml:mfenced close=")" open="(" separators=""NO2-+NO3-/NH4+ of total effluent nitrite and nitrate production to ammonia consumption was kept at about 0.053 at the last stage (days 181-218). Anaerolineaceae (26.92%), Candidatus Brocadia (3.96%), Candidatus-Kuenenia (4.69%), Armatimonadetes-norank (4.25%), Limnobacter (4.15%), Xanthomonadaceae (3.07%) and Ignavibacterium (2.87%) were the dominant genera in the SNAD system for treating ADLSW. The quantitative polymerase chain reaction (qPCR) results further confirmed that the co-existence and enrichment of anammox bacteria, ammonium oxidising bacteria (AOB) and denitrifying bacteria (HB) in the bioreactor.