Evaluation of NOx removal from flue gas and Fe(II)EDTA regeneration using a novel BTF–ABR integrated system

• Published in: Journal of hazardous materials 2021-08, Vol.415, p.125741-125741, Article 125741
• Main Authors: Wang, Yanling, Li, Jianjun, Huang, Shaobin, Huang, Xingzhu, Hu, Wenzhe, Pu, Jia, Xu, Meiying
• Format: Article
• Language: English
• Subjects: Biological reduction; Fe(II)EDTA regeneration; Microbial community; NOx removal; Real–time PCR
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.125741

A promising process is under development for the removal of NOx and regeneration of Fe(II)EDTA in a novel biotrickling filter–anaerobic baffled reactor (BTF–ABR) integrated system at 50 ± 0.5 ℃. In this work, we investigated the NOx removal capacity of a BTF under different O2 concentrations (7.0 vol%, 5.25 vol% and 3.5 vol%), and tested the effect of an ABR on NOx removal and regeneration of Fe(II)EDTA. The results showed that the NOx removal capacity was significantly increased with the O2 concentration reduced from 7.0% to 3.5%. The microoxygen environment produced by the BTF–ABR integrated system was more conducive to the removal of NOx and regeneration of Fe(II)EDTA compared with that in the BTF. Real–time polymerase chain reaction (PCR) analysis showed that the coordinated expression of denitrification genes was the major reason for no N2O emission, along with no nitrate and nitrite accumulation. The 16S rRNA gene amplicon sequencing analysis showed that the cooperation of denitrifying bacteria (Klebsiella, Petrimonas, Rhodococcus and Ochrobactium) and iron–reducing bacteria (Klebsiella, Geobacter and Petrimonas) in the system was the key to the stable and efficient removal of NOx and the regeneration of Fe(II)EDTA simultaneously. [Display omitted] •A novel BTF–ABR integrated system was used to remove NOx and regenerate Fe(II)EDTA.•A maximum NOx RE of 98.4% was achieved and NOx RE could be maintained above 90%.•Cooperation of functional bacteria achieved NOx removal and Fe(II)EDTA regeneration.•Coordinated expression of denitrification genes was vital for non–secondary pollution.