Exogenous N-acyl-homoserine lactones accelerate resuscitation of starved anaerobic granular sludge after long-term stagnation

Abstract

So as to accelerate the resuscitation of starved anaerobic granular sludge after long-term stagnation, an innovative method was tried derived from the regulation of N-acyl-homoserine lactones (AHLs)-mediated quorum sensing (QS). The mixture of four AHLs was added to the starved anaerobic granular sludge system in this research. The results confirmed that the exogenous AHLs shortened the recovery time of the granular sludge, and improved the treatment performance and methanogenic capacity of the recovered anaerobic sludge to the level before stagnation. At the same time, exogenous AHLs enhanced the synthesis of extracellular polymeric substances (EPS) during the resuscitation period of starved anaerobic granular sludge. The outcomes of microbial composition detection showed that the change of bacterial and methanogenic bacteria communities towards accelerated performance recovery was significantly correlated with exogenous AHLs. This exploration provided a new technical idea for speeding up the recovery of starved anaerobic granular sludge.