4 Conclusions
This study aimed to investigate the effectiveness of biofilm reactors
inoculated with azo dye degrading Shewanella and using different
carrier materials (biochar, moving bed biofilm reactor (MBBR), and
polypropylene carrier (PPC)) for the decolorization of Reactive Black 5
(RB5). The results showed that all three carriers exhibited good RB5
decolorization performance, with varying degrees of efficiency. Although
the effluent from the biochar reactor and the two polymer carrier
reactors showed some similarity in UV-Vis and FTIR results, LC-MS
analysis revealed significant differences in the degradation pathways of
RB5, indicating the role of carrier materials and microbial communities
in the process.
The MBBR carrier had a rough surface with a large number of microbial
aggregates clustered at the protruding tooth-like positions, which
intertwined with each other and were not easily detached, resulting in
good stability of MBBR operation. Furthermore, the sequencing results
showed that the carrier material had a significant impact on the
microbial structure in the reactor. The differences in the microbial
community structure were relatively small between the MBBR and PPC
carriers compared to the almond shell biochar carrier. The highly
efficient degrading microbial communities on the biochar carrier were
markedly different from those on the MBBR and PPC polymer carrier
reactors, with Shewanella being the dominant functional bacteria
in the MBBR and PPC polymer carrier reactors.
Overall, this study demonstrated that the physicochemical properties of
the carrier materials had a significant impact on the microbial
community in the reactor, which in turn influenced the degradation
efficiency of RB5. The findings provide valuable insights into the
optimization of biofilm reactors for the treatment of dye-containing
wastewater.