Removal of nitric oxide from biomass combustion by thermophilic nitrification-aerobic denitrification combined with catalysis in membrane biofilm reactor

Thermophilic nitrification-aerobic denitrification combined with catalysis was operated for treat flue gas nitrogen oxide (NO) from biomass combustion during 180 consecutive days at 45, 52, 60 degrees C. The thermophilic catalytic membrane biofilm reactor (TCMBR) achieved the best NO removal efficiency of 94.5%, and the maximum elimination capacity was 1165.9 g-NO.m(-3).h(-1) at 60 degrees C, respectively. Catalysis promoted thermophilic nitrification/denitrification and enhance the elimination capacity up from 6.9 to 24.1 g-NO.m(-3).h(-1). Dominant genera Burkholderiales, Neisseriales, Sphingobacteriales and Bacillales participated in nitrification and denitrification simultaneously. Thermophilic nitrifying bacterium, aerobic denitrifying bacterium and ammoniating bacteria co-existed with the TCMBR60, TCMBR60 had no ammonification because of lacking PmoA and HAO, a rise in temperature would lead to the decrease of nitrobacteria, denitrifiers, ammoniated bacteria and the change of microbial nitrogen metabolism, as shown by Illumina high-throughput sequencing. Thermophilic nitrification-aerobic denitrification combined with catalysis could contribute to NO removal under thermophilic conditions in TCMBR60.