Mechanistic insights into 1,2,4-trichlorobenzene removal in flue gas by aerobic denitrifying membrane biofilm reactor

1,2,4-Trichlorobenzene (1,2,4-TrClBz) as dioxin indicator in municipal solid waste incineration can increase risk of human health. Aerobic denitrifying membrane biofilm reactor (MBfR) was investigated for 1,2,4-TrClBz removal in flue gas. During the 75 days of operation, 1,2,4-TrClBz removal efficiency achieved 94%. Pseudomonas, Halomonas, Paracoccus, Thauera, Azoarcus, Proteiniphilum, Mesorhizobium, Pelagibacterium, Chelativorans were the core 1,2,4-TrClBz biodegrading-denitrifying bacteria. 1,2,4-TrClBz biodegradation genes and denitrification genes were responsible for the oxidation of 1,2,4-TrClBz and nitrate reduction. 1,2,4-TrClBz was degraded by ring-cleavage before aerobic dechlorination, 1,2,4-TrClBz bio-oxidation was coupled to denitrification formed redox between 1,2,4-TrClBz and nitrate, as shown by metagenomic sequencing and untargeted metabolomic analysis. Therefore, MBfR effectively achieved bioremoval and biodegradation of 1,2,4-TrClBz in flue gas by aerobic denitrification, which may provide a feasible and environment-friendly biotechnique for decontamination of chlorobenzene compounds in flue gas.