Enhancement of methane production in anaerobic digestion of sewage sludge by thermal hydrolysis pretreatment

•The optimal THP conditions of 180 °C and 76 min were obtained from RSM.•The SMPs and EPSs in sewage sludge converted to low molecular substances through THP.•Both acetoclastic and hydrogenotrophic methanogens were dominant in the AD with THP. This study was performed to optimize thermal hydrolysis...

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Bibliographic Details
Published in:Bioresource technology 2018-07, Vol.259, p.207-213
Main Authors: Choi, Jae-Min, Han, Sun-Kee, Lee, Chae-Young
Format: Article
Language:English
Subjects:
Anaerobic digestion
Microbial community
Response surface methodology
Sewage sludge
Thermal hydrolysis pretreatment
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Summary:•The optimal THP conditions of 180 °C and 76 min were obtained from RSM.•The SMPs and EPSs in sewage sludge converted to low molecular substances through THP.•Both acetoclastic and hydrogenotrophic methanogens were dominant in the AD with THP. This study was performed to optimize thermal hydrolysis pretreatment (THP) of sewage sludge for enhanced anaerobic digestion (AD). Using the response surface methodology (RSM), the optimal conditions were found 180 °C of reaction temperature and 76 min of reaction time. Through THP under optimal conditions, high molecular substances in sewage sludge such as soluble microbial by-products (SMPs) and extracellular polymeric substances (EPSs) were hydrolyzed into low molecular ones without the generation of refractory compounds. The microbial community analysis revealed that relative abundances of Methanomicrobia such as Methanosarcina, Methanosaeta (acetoclastic methanogens), and Methanoculleus (hydrogenotrophic methanogens) in AD with THP were higher than those in conventional AD.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2018.02.123