The application of magneto-biological effects in wastewater treatment has been brought under the spotlight recently. This work explored the dual effects of magnetic field (MF) and exogenous N-hexanoyl-l-homoserine lactone (C6-HSL) on activated sludge granulation. Results showed that exposure to MF and C6-HSL obviously accelerated the aerobic granulation process and promoted the secretion of extracellular polymeric substances, especially polysaccharides, humic acid-like substances, aromatic proteins, and tryptophan-like substrates. Illumina MiSeq sequencing results indicated that the introduction of MF and C6-HSL can increase the diversity and richness of microbial community without antagonism, and the biological basis for rapid granulation process in this study was the enrichment of slow-growing bacteria Candidatus_Competibacter. Besides, the overgrowth of filamentous bacteria Thiothrix could be suppressed due to the presence of MF, improving the stabilities of aerobic granular sludge. This study provides a new understanding of the MF and C6-HSL effects on rapid aerobic granulation when treating the low-strength wastewater.
Keywords: Aerobic granular sludge; Extracellular polymeric substance; Microbial community; N-acyl-homoserine lactones (AHLs); Weak magnetic field.
Copyright © 2022. Published by Elsevier Ltd.