Enhancement of the removal and settling performance for aerobic granular sludge under hypersaline stress. (December 2018)

• Record Type: Journal Article
• Authors: Ou, Dong; Li, Wei; Li, Hui; Wu, Xiao; Li, Cheng; Zhuge, Yangyang; Liu, Yong-di
• Is Part Of: Chemosphere. Volume 212(2018)
• Page Start: 400
• Page End: 407
• Publication Date: 2018-12
• Subjects: Saline wastewater -- Removal and settling performance -- Aerobic granular sludge -- Microbial community succession -- PICRUSt; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.08.096
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The aerobic granular sludge (AGS) dominated by halophilic microorganisms, was successfully cultivated in a lab-scale sequencing batch reactor (SBR) under varying salinity levels (from 0% to 6% (w/v)). Removal performance of AGS improved with the increase of salinity and increased up to 42.86 mg g −1 VSS h −1 at 6% salinity. Increased salinity resulted in better settling performance of AGS in terms of the sludge volume index (SVI), which was initially 148.80 mL/g at 0% salinity and gradually decreased to 59.1 mL/g at 6% salinity. The increase of salinity stimulated bacteria to secret excessive extracellular polymeric substances (EPS), with its highest production of 725.5 mg/(g·VSS) at 5% salinity. The total protein (PN) exhibited highly positive correlation with the total EPS (R = 0.951), indicating that selective secretion of some functional PN played a key constituent in resisting the external osmotic pressure and improving sludge performance. Salinicola, accounted for up to 91% relative abundance at 6% salinity, showed the high positive correlation (R = 0.953) with salinity. The enrichment of such halophilic or halotolerant microbial community assured both stable and improved removal performance in the AGS system. The enrichment of salt response pathways and altered metabolic processes for salt-tolerant bacteria indicated that the microbial community formed special metabolic pattern under long-term hypersaline stress to maintain favourable cellular activity and removal performance. Highlights: AGS dominated by halophilic microorganisms was successfully cultivated at 6% salinity. Increased salinity resulted in enhancement of removal and settling performance of AGS. The functional groups of PN contributed a lot to salt-tolerance ability of AGS. Salinicola (91% at 6% salinity) showed the highly positive correlation with salinity.