PacBio Research Topics
1. S&TE: Enhanced removal of 17α-ethinyl estradiol by aerobic granulation of nitrifying activated sludge
English title : Aerobic granulation of nitrifying activated sludge enhanced removal of 17α-ethinylestradiol
Numerous studies have shown that nitrifying activated sludge (NAS) can remove 17α-ethinyl estradiol (EE2) pollution. In this study, the removal efficiency of EE2 by nitrifying granular sludge (NGS) was detected in a sequencing batch batch reactor (SBR), and then the artificial neural network (ANN) model and Spearman correlation analysis were used to prove that nitrite accumulation is an The key factor for the removal of EE2, it is finally inferred that under the same aeration conditions (0.15 L/min), the removal efficiency of NGS is higher than that of non-granular structures because the dense structure makes nitrite easier to accumulate.
Full-length 16S rRNA gene sequencing revealed that EE2 could strongly affect the microbial communities of NAS and NGS. NGS showed an increase in community diversity and richness, whereas NAS showed a decrease. Furthermore, the relative abundance of Nitrosomonas (ammonia oxidizing bacteria, AOB) was significantly decreased in both NAS and NGS, but the expression of amoA and nirK genes was upregulated in Nitrosomonas. This suggests that N. eutropha is forced to regulate its gene expression to resist the negative effects of EE2. Denitrifying bacteria, such as Comamonas , were enriched in both NAS and NGS, and more species of heterotrophic bacteria were found to degrade EE2 contamination in NGS by full-length 16S sequencing. The conversion pathway of EE2 in NAS and NGS is consistent. Ammonia monooxygenase (AMO) in AOB directly biotransforms EE2, while active substances produced by AOB chemically transform EE2. EE2 and its transformation products (TPs) produced by degradation of AOB by heterotrophic bacteria. According to TPs and microbial structure, NGS showed better performance than NAS in the synergistic removal of EE2 by AOB and heterotrophic bacteria. These results provide important information for the development and application of NGS to treat estrogen-containing and high-intensity ammonia-nitrogen wastewater.
Article link:
《Science of The Total Environment》