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

Abstract 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 °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 °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.