Accelerated performance recovery of anaerobic granular sludge after temperature shock: Rapid construction of protective barriers (EPS) to optimize microbial community composition base on quorum sensing

Poor temperature shock resistance of anaerobic granular sludge is one of its main disadvantages. In this study, enhancing the temperature shock resistance of AnGS by regulating quorum sensing based on the exogenous addition of The results indicated that adding AHLs significantly enhanced the COD removal and specific methanogenic activity of AnGS after temperature shock, and the recovery time was reduced by 4 days. The sludge breakage and particle size reduction induced by temperature shock were attenuated by AHLs-mediated QS. Meanwhile, exogenous AHLs increased EPS concentration and the number of hydrophobic functional groups in AnGS. The addition of AHLs reduced the ratio of Firmicutes to Bacteroidota , leading to higher microbial community stability. The enrichment of major functional bacteria and hydrogenotrophic methanogens was promoted by AHLs. The increased EPS induced by AHLs provided the protection for microbial community optimization, leading to the rapid recovery of the temperature-shocked AnGS performance.