Process assessment associated to microbial community response provides insight on possible mechanism of waste activated sludge digestion under typical chemical pretreatments

Current studies have employed various chemicals for disintegrating and hydrolyzing microbial cells in waste activated sludge (WAS). However, a comprehensive process assessment over the whole anaerobic digestion process has seldom been proposed. Besides, the characterization of microbial community re...

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Bibliographic Details
Published in:Energy (Oxford) 2017-10, Vol.137, p.457-467
Main Authors: Zhou, Aijuan, Zhang, Jiaguang, Varrone, Cristiano, Wen, Kaili, Wang, Guoying, Liu, Wenzong, Wang, Aijie, Yue, Xiuping
Format: Article
Language:English
Subjects:
Acidification
Acids
Activated sludge
Anaerobic digestion
Anaerobic microorganisms
Anaerobic processes
Biogas
Chemical pretreatments
Chemicals
Communities
Community structure
Cyclodextrin
Cyclodextrins
Disintegration
Methanogenesis
Microbial community
Microorganisms
Peroxide
Pollutants
Process management
Pyrosequencing
Sludge
Sludge digestion
Sodium
Solubilization
Surfactants
Waste activated sludge (WAS)
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Summary:Current studies have employed various chemicals for disintegrating and hydrolyzing microbial cells in waste activated sludge (WAS). However, a comprehensive process assessment over the whole anaerobic digestion process has seldom been proposed. Besides, the characterization of microbial community responses to these chemicals is not well understood. In this study, the effects of five typical chemicals: solubilizer (β-cyclodextrin, CD), alkaline (NaOH), peroxide (peracetic-acid, PA), biological (rhamnolipid, RL) and chemical (sodium dodecylsulphate, SDS) surfactants on WAS digestion were examined. Higher efficiencies of WAS solubilization, hydrolysis and acidification were achieved by CD treatment, followed by RL and SDS. Methanogenesis was also strongly chemicals-dependent. Shifts in microbial community structure were observed in all chemical-pretreated WAS. The community in RL, CD and PA was dominated by microorganisms that anaerobically hydrolyze organics to acids, while that in NaOH and SDS was mainly associated to biogas production. This study proved that the overall performance of WAS digestion was substantially depended on the initial chemical pretreatments, which in turn influenced and was related to the microbial community structures. Although the economic advantage might not be clear yet, the findings obtained in this work may provide a scientific basis for the potential implementation of chemicals for WAS treatment. [Display omitted] •Effects of five typical chemical pretreatments on WAS digestion were examined.•Comprehensive process assessment over the whole AD process was proposed.•The community in RL, CD and PA was dominated by acidification microorganisms.•The community in NaOH and SDS was associated to biogas production.•Underlying mechanism of how and why chemicals enhance WAS digestion was tackled.
ISSN:0360-5442
1873-6785
DOI:10.1016/j.energy.2017.02.166