Control of H 2 S generation in simultaneous removal of NO and SO 2 by rotating drum biofilter coupled with Fe II (EDTA).

Simultaneous removal of SO2 and NO from flue gas can be biologically achieved by the rotating drum biofilter with FeII (EDTA) as a solvent. One issue related with this process is the generation of H2 S. To control its generation, the pathways of H2 S formation were investigated, and the parametric tests were conducted. The addition of FeII (EDTA) (10 mM) increased the removal efficiency of NO and SO2 , while the S2- concentration decreased from 81 to 3.5 mM. The parametric tests showed that the high NO concentration favored the SO2 removal and significantly inhibited the H2 S generation. High-throughput sequencing showed that the dominant denitrifying bacteria were Pseudomonas (9.09%), and the main sulfate-reducing bacteria were Desulfovibrio (5.84%). The long-term operation confirmed that the system could effectively simultaneous perform biological denitrification and desulfurization, and the H2 S could be controlled.