Start-up,formation and microbial community analysis of aerobic granules in SABR for treatment of organic wastewater containing aniline and chloroanilines

Abstract:

The granulation of aerobic sludges for high-rate biodegradation of organic wastewater containing aniline and chloroanilines was investigated in a laboratory-scale sequencing airlift bioreactor (SABR). Aerobic granules were observed in 15days after start-up in SABR. After subsequent 83days, SABR was operated sequentially in superficial air velocity of 2.4cm/s, COD loadings of 1.0～3.6kg/(m³·d) and (chloro-)anilines loadings increased stepwise to 1kg/(m³·d), a steady-state performance of aerobic granular SABR was achieved at last, as evidenced by high and stable COD and (chloro-)anilines removal efficiencies of above 90% and 99.9%, respectively. Mature granules with median size of 0.45～2.5mm, minimal settling velocity of 62.1m/h, and SVI of 56mL/g were developed. Aerobic granular sludge displayed noteworthy SOUR, specific (chloro-)anilines degradation rates, PN content and PN/PS ratio in EPS extracts as 154mgDO/(gVSS·h), 0.18g/(gVSS·d), 28.0±1.9mg/gVSS and 6.5mg/mg respectively, indicating that they had high activity and ability to withstand high (chloro-)anilines loadings. Phylogenetic analysis of (chloro-)anilines-degrading aerobic granules indicated that β-、γ-Proteobacteria and Flavobacteria were dominant classes and the predominance bacteria were closely related to Pseudomonas sp. and Flavo-bacterium sp. Compared to chloroanilines-degrading aerobic granules, the population diversity was higher in the aniline and chloroaniline-degrading aerobic granules.