Population dynamics during startup of thermophilic anaerobic digesters: The mixing factor

Handle URI:
http://hdl.handle.net/10754/563070
Title:
Population dynamics during startup of thermophilic anaerobic digesters: The mixing factor
Authors:
Ghanimeh, Sophia A.; Saikaly, Pascal ( 0000-0001-7678-3986 ) ; Li, Dong; El-Fadel, Mutasem E.
Abstract:
Two thermophilic digesters were inoculated with manure and started-up under mixed and stagnant conditions. The Archaea in the mixed digester (A) were dominated by hydrogenotrophic Methanobateriaceae (61%) with most of the methane being produced via syntrophic pathways. Methanosarcinales (35%) were the only acetoclastic methanogens present. Acetate dissipation seems to depend on balanced hydrogenotrophic-to-acetotrophic abundance, which in turn was statistically correlated to free ammonia levels. Relative abundance of bacterial community was associated with the loading rate. However, in the absence of mixing (digester B), the relationship between microbial composition and operating parameters was not discernible. This was attributed to the development of microenvironments where environmental conditions are significantly different from average measured parameters. The impact of microenvironments was accentuated by the use of a non-acclimated seed that lacks adequate propionate degraders. Failure to disperse the accumulated propionate, and other organics, created high concentration niches where competitive and inhibiting conditions developed and favored undesired genera, such as Halobacteria (65% in B). As a result, digester B experienced higher acid levels and lower allowable loading rate. Mixing was found necessary to dissipate potential inhibitors, and improve stability and loading capacity, particularly when a non-acclimated seed, often lacking balanced thermophilic microflora, is used. © 2013 Elsevier Ltd.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Sciences and Engineering (BESE) Division; Environmental Science and Engineering Program; Water Desalination & Reuse Research Cntr; Environmental Biotechnology Research Group
Publisher:
Elsevier BV
Journal:
Waste Management
Issue Date:
Nov-2013
DOI:
10.1016/j.wasman.2013.06.011
PubMed ID:
23830181
Type:
Article
ISSN:
0956053X
Sponsors:
This work was supported by the National Council for Scientific Research, Lebanon and the Masri Institute of Energy and Natural Resources at the American University of Beirut. Special thanks are extended to the United States Agency for International Development for its support in acquiring the equipment used in the experimental program. Also, special thanks are extended to Mr. M. Alarawi and Dr. S. Ali at the Bioscience Core Laboratory at KAUST.
Appears in Collections:
Articles; Environmental Science and Engineering Program; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorGhanimeh, Sophia A.en
dc.contributor.authorSaikaly, Pascalen
dc.contributor.authorLi, Dongen
dc.contributor.authorEl-Fadel, Mutasem E.en
dc.date.accessioned2015-08-03T11:35:06Zen
dc.date.available2015-08-03T11:35:06Zen
dc.date.issued2013-11en
dc.identifier.issn0956053Xen
dc.identifier.pmid23830181en
dc.identifier.doi10.1016/j.wasman.2013.06.011en
dc.identifier.urihttp://hdl.handle.net/10754/563070en
dc.description.abstractTwo thermophilic digesters were inoculated with manure and started-up under mixed and stagnant conditions. The Archaea in the mixed digester (A) were dominated by hydrogenotrophic Methanobateriaceae (61%) with most of the methane being produced via syntrophic pathways. Methanosarcinales (35%) were the only acetoclastic methanogens present. Acetate dissipation seems to depend on balanced hydrogenotrophic-to-acetotrophic abundance, which in turn was statistically correlated to free ammonia levels. Relative abundance of bacterial community was associated with the loading rate. However, in the absence of mixing (digester B), the relationship between microbial composition and operating parameters was not discernible. This was attributed to the development of microenvironments where environmental conditions are significantly different from average measured parameters. The impact of microenvironments was accentuated by the use of a non-acclimated seed that lacks adequate propionate degraders. Failure to disperse the accumulated propionate, and other organics, created high concentration niches where competitive and inhibiting conditions developed and favored undesired genera, such as Halobacteria (65% in B). As a result, digester B experienced higher acid levels and lower allowable loading rate. Mixing was found necessary to dissipate potential inhibitors, and improve stability and loading capacity, particularly when a non-acclimated seed, often lacking balanced thermophilic microflora, is used. © 2013 Elsevier Ltd.en
dc.description.sponsorshipThis work was supported by the National Council for Scientific Research, Lebanon and the Masri Institute of Energy and Natural Resources at the American University of Beirut. Special thanks are extended to the United States Agency for International Development for its support in acquiring the equipment used in the experimental program. Also, special thanks are extended to Mr. M. Alarawi and Dr. S. Ali at the Bioscience Core Laboratory at KAUST.en
dc.publisherElsevier BVen
dc.subject16S rRNA gene pyrosequencingen
dc.subjectMicrobial dynamicsen
dc.subjectMixingen
dc.subjectStartupen
dc.subjectThermophilic anaerobic digestionen
dc.titlePopulation dynamics during startup of thermophilic anaerobic digesters: The mixing factoren
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentEnvironmental Science and Engineering Programen
dc.contributor.departmentWater Desalination & Reuse Research Cntren
dc.contributor.departmentEnvironmental Biotechnology Research Groupen
dc.identifier.journalWaste Managementen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, American University of Beirut, Lebanonen
kaust.authorSaikaly, Pascalen
kaust.authorLi, Dongen

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