Decolorization of Brilliant Scarlet GR enhanced by bioaugmentation and redox mediators under high-salt conditions

The synergistic effects of bioaugmentation and redox mediator catalysis on Brilliant Scarlet GR decolorization under high-salt conditions were investigated. Two start-up models were tested in simulated anaerobic sequencing batch reactors (AnSBRs). The results showed that the start-up was shortened by bioaugmentation with salt-tolerant strain TL, and the biodecolorization was promoted by adding anthraquinone after acclimatization. The start-up time of non-bioaugmented and bioaugmented activated sludge systems were about 9 d and 5 d, respectively. It was proved that anthraquinone could not enhance the process in the start-up stage because it would inhibit some potential azo-reducing microorganisms in the non-acclimatized activated sludge. When anthraquinone was added to the acclimatized bioaugmented system, the maximal decolorization rate was 700–800 mg L−1 d−1. PCR–DGGE fingerprints demonstrated that both the diversity and pattern of microbial community were affected by the addition of bioaugmentation strain and anthraquinone. All the dominant bands were confirmed as anaerobic bacteria.