Azo dyes are significant organic pollutants known for their adverse effects on humans and aquatic life. In this study, anthraquinone-2-sulfonate (AQS) immobilized on biochar (BC) was employed as a novel carrier in up-flow anaerobic fixed-bed reactors to induce specific biofilm formation and promote the biotransformation efficiency of azo dyes. Novel carrier-packed reactor 1 (R1) and BC-packed reactor 2 (R2) were used to treat red reactive 2 (RR2) under continuous operation for 175 days. The decolorization rates of R1 and R2 were 96-83% and 91-73%, respectively. The physicochemical characteristics and extracellular polymeric substances (EPS) of the biofilm revealed a more stable structure in R1. Furthermore, the microbial community in R1 interacted more closely with each other and contained more keystone genera. Overall, this study provides a feasible method for improving the biotransformation of azo dyes, thus providing support for practical applications in wastewater treatment projects.
Keywords: Anaerobic biofilm; Biochar; Keystone genera; Microbial community structure; Redox mediators.
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