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Article: Collision frequencies of microbial aggregates with small particles by differential sedimentation

TitleCollision frequencies of microbial aggregates with small particles by differential sedimentation
Authors
Issue Date2002
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/est
Citation
Environmental Science And Technology, 2002, v. 36 n. 3, p. 387-393 How to Cite?
AbstractCollision and coagulation rates between microbial aggregates and small particles were measured for individual aggregates (1.0-2.5 mm) that settled through a suspension of fluorescent yellow-green (YG) particles (2.83 μm) placed in a settling column. The microbial aggregates, with an average fractal dimension of 2.26, were generated in a lab-scale sequencing batch reactor (SBR) and also collected from a full-scale activated sludge (AS) treatment system. As calculated from comparisons between the settling velocities observed and those predicted by Stokes' law for impermeable particles, the average fluid collection efficiencies were 0.08 for the SBR aggregates and 0.14 for the AS flocs, which were much lower than those previously reported for nonbiological aggregates of latex microspheres. The collision frequency functions between microbial aggregates and small YG particles were 2 orders of magnitude lower than predicted by the rectilinear model but 1 order of magnitude greater than predicted by a curvilinear model. The overall scavenging efficiencies of suspended particles by the falling microbial aggregates compared well with those observed for the nonbiological aggregates, while the particle removal efficiencies from the flow internal to the microbial aggregates were 1 order of magnitude higher than those of the nonbiological aggregates. It is argued that the permeability of microbial aggregates could be reduced by exopolymeric material clogging the pores within the aggregates. The internal permeation through a bioaggregate thus may not be significant enough to be included in the calculation of its settling velocity; however, the intra-aggregate flow cannot be simply neglected where coagulation is concerned. Streamlines still can penetrate the interior of microbial aggregates, allowing greater collision frequencies with other particles than predicted by the curvilinear model. The narrow and convoluted internal flow passages resulting from the collection of extracellular polymeric substances may also contribute to the higher interior particle removal efficiencies of microbial aggregates than those of more permeable, nonbiological aggregates.
Persistent Identifierhttp://hdl.handle.net/10722/71607
ISSN
2015 Impact Factor: 5.393
2015 SCImago Journal Rankings: 2.664
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLi, XYen_HK
dc.contributor.authorYuan, Yen_HK
dc.date.accessioned2010-09-06T06:33:31Z-
dc.date.available2010-09-06T06:33:31Z-
dc.date.issued2002en_HK
dc.identifier.citationEnvironmental Science And Technology, 2002, v. 36 n. 3, p. 387-393en_HK
dc.identifier.issn0013-936Xen_HK
dc.identifier.urihttp://hdl.handle.net/10722/71607-
dc.description.abstractCollision and coagulation rates between microbial aggregates and small particles were measured for individual aggregates (1.0-2.5 mm) that settled through a suspension of fluorescent yellow-green (YG) particles (2.83 μm) placed in a settling column. The microbial aggregates, with an average fractal dimension of 2.26, were generated in a lab-scale sequencing batch reactor (SBR) and also collected from a full-scale activated sludge (AS) treatment system. As calculated from comparisons between the settling velocities observed and those predicted by Stokes' law for impermeable particles, the average fluid collection efficiencies were 0.08 for the SBR aggregates and 0.14 for the AS flocs, which were much lower than those previously reported for nonbiological aggregates of latex microspheres. The collision frequency functions between microbial aggregates and small YG particles were 2 orders of magnitude lower than predicted by the rectilinear model but 1 order of magnitude greater than predicted by a curvilinear model. The overall scavenging efficiencies of suspended particles by the falling microbial aggregates compared well with those observed for the nonbiological aggregates, while the particle removal efficiencies from the flow internal to the microbial aggregates were 1 order of magnitude higher than those of the nonbiological aggregates. It is argued that the permeability of microbial aggregates could be reduced by exopolymeric material clogging the pores within the aggregates. The internal permeation through a bioaggregate thus may not be significant enough to be included in the calculation of its settling velocity; however, the intra-aggregate flow cannot be simply neglected where coagulation is concerned. Streamlines still can penetrate the interior of microbial aggregates, allowing greater collision frequencies with other particles than predicted by the curvilinear model. The narrow and convoluted internal flow passages resulting from the collection of extracellular polymeric substances may also contribute to the higher interior particle removal efficiencies of microbial aggregates than those of more permeable, nonbiological aggregates.en_HK
dc.languageengen_HK
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/esten_HK
dc.relation.ispartofEnvironmental Science and Technologyen_HK
dc.subject.meshGeologic Sediments - microbiology-
dc.subject.meshPermeability-
dc.subject.meshPolymers-
dc.subject.meshSewage - microbiology-
dc.subject.meshSoil Microbiology-
dc.titleCollision frequencies of microbial aggregates with small particles by differential sedimentationen_HK
dc.typeArticleen_HK
dc.identifier.emailLi, XY:xlia@hkucc.hku.hken_HK
dc.identifier.authorityLi, XY=rp00222en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1021/es010681den_HK
dc.identifier.pmid11871553-
dc.identifier.scopuseid_2-s2.0-0036468329en_HK
dc.identifier.hkuros69205en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0036468329&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume36en_HK
dc.identifier.issue3en_HK
dc.identifier.spage387en_HK
dc.identifier.epage393en_HK
dc.identifier.isiWOS:000173626900030-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridLi, XY=26642887900en_HK
dc.identifier.scopusauthoridYuan, Y=36553559300en_HK

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