A laboratory-scale sequencing airlift bioreactor
continuously treating high-level 4-chloroaniline (4-ClA)
wastewater was used for studying the effect of 4-ClA on
the characteristics and microbial community of aerobic
granular sludge. The granulation of aerobic sludge and
efficient pollutant removal performance were developed
via shortening sludge settling time and gradually increasing
influent 4-ClA concentration to around 400 mg L
-1.
However, the granular sludge reactor deteriorated with the
4-ClA loading rate above 0.8 kg m
-3 d
-1. Denaturing
gradient gel electrophoresis and real-time quantitative PCR
were applied to investigate the microbial community succession
during the start-up and recovery of bioreactor. The
results showed that the performance of granular reactor
was significantly influenced by the microbial community of
aerobic granule, and stable aerobic granule was dominated
with
β-Proteobacteria (61.28 %),
Flavobacteriales,
Planctomycetales,
Clostridiales, and
Acidobacteria. Since
Thauera
(21.55 %) related to the genus
β-Proteobacteria
was abundant in the stable 4-ClA-degrading granular
sludge, it was speculated as the main 4-ClA-degrading
bacteria. Under high chloroaniline level, the sludge granulation
may maintain the stability of the bioreactor via
adjusting the composition of microbial community and
abundance of functional microorganism. This paper provided
useful information for better understanding the
change of microbial community characteristics under highlevel
toxic organic pollutants and process optimizing.
