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Flowing biofilms as a transport mechanism for biomass through porous media under laminar and turbulent conditions in a laboratory reactor system

Flowing biofilms as a transport mechanism for biomass through porous media under laminar and turbulent conditions in a laboratory reactor system
Flowing biofilms as a transport mechanism for biomass through porous media under laminar and turbulent conditions in a laboratory reactor system
Fluid flow has been shown to be important in influencing biofilm morphology and causing biofilms to flow over surfaces in flow cell experiments. However, it is not known whether similar effects may occur in porous media. Generally, it is assumed that the primary transport mechanism for biomass in porous media is through convection, as suspended particulates (cells and flocs) carried by fluid flowing through the interstices. However, the flow of biofilms over the surfaces of soils and sediment particles, may represent an important flux of biomass, and subsequently affect both biological activity and permeability. Mixed species bacterial biofilms were grown in glass flow cells packed with 1 mm diameter glass beads, under laminar or turbulent flow (porous media Reynolds number = 20 and 200 respectively). The morphology and dynamic behavior reflected those of biofilms grown in the open flow cells. The laminar biofilm was relatively uniform and after 23 d had inundated the majority of the pore spaces. Under turbulent flow the biofilm accumulated primarily in protected regions at contact points between the beads and formed streamers that trailed from the leeward face. Both biofilms caused a 2 to 3-fold increase in friction factor and in both cases there were sudden reductions in friction factor followed by rapid recovery, suggesting periodic sloughing and regrowth events. Time-lapse microscopy revealed that under both laminar and turbulent conditions biofilms flowed over the surface of the porous media. In some instances ripple structures formed. The velocity of biofilm flow was on the order of 10 mum h(-1) in the turbulent flow cell and 1.0 mum h(-1) in the laminar flow cell.
0892-7014
161-168
Stoodley, P.
08614665-92a9-4466-806e-20c6daeb483f
Dodds, I.
e1f87920-d7ad-4d1b-a53b-878a0a18e47d
De Beer, D.
dacf8ca7-27c7-4572-882a-7111159d10cc
Scott, H. Lappin
85cc5692-f2d8-4796-847e-c33419e69fcf
Boyle, J.D.
368bdeb9-d77b-42e8-811a-09fb24a33c12
Stoodley, P.
08614665-92a9-4466-806e-20c6daeb483f
Dodds, I.
e1f87920-d7ad-4d1b-a53b-878a0a18e47d
De Beer, D.
dacf8ca7-27c7-4572-882a-7111159d10cc
Scott, H. Lappin
85cc5692-f2d8-4796-847e-c33419e69fcf
Boyle, J.D.
368bdeb9-d77b-42e8-811a-09fb24a33c12

Stoodley, P., Dodds, I., De Beer, D., Scott, H. Lappin and Boyle, J.D. (2005) Flowing biofilms as a transport mechanism for biomass through porous media under laminar and turbulent conditions in a laboratory reactor system. Biofouling, 21 (3-4), 161-168.

Record type: Article

Abstract

Fluid flow has been shown to be important in influencing biofilm morphology and causing biofilms to flow over surfaces in flow cell experiments. However, it is not known whether similar effects may occur in porous media. Generally, it is assumed that the primary transport mechanism for biomass in porous media is through convection, as suspended particulates (cells and flocs) carried by fluid flowing through the interstices. However, the flow of biofilms over the surfaces of soils and sediment particles, may represent an important flux of biomass, and subsequently affect both biological activity and permeability. Mixed species bacterial biofilms were grown in glass flow cells packed with 1 mm diameter glass beads, under laminar or turbulent flow (porous media Reynolds number = 20 and 200 respectively). The morphology and dynamic behavior reflected those of biofilms grown in the open flow cells. The laminar biofilm was relatively uniform and after 23 d had inundated the majority of the pore spaces. Under turbulent flow the biofilm accumulated primarily in protected regions at contact points between the beads and formed streamers that trailed from the leeward face. Both biofilms caused a 2 to 3-fold increase in friction factor and in both cases there were sudden reductions in friction factor followed by rapid recovery, suggesting periodic sloughing and regrowth events. Time-lapse microscopy revealed that under both laminar and turbulent conditions biofilms flowed over the surface of the porous media. In some instances ripple structures formed. The velocity of biofilm flow was on the order of 10 mum h(-1) in the turbulent flow cell and 1.0 mum h(-1) in the laminar flow cell.

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More information

Published date: 2005
Organisations: Engineering Mats & Surface Engineerg Gp

Identifiers

Local EPrints ID: 155949
URI: http://eprints.soton.ac.uk/id/eprint/155949
ISSN: 0892-7014
PURE UUID: aba6b633-6693-40ab-bad5-5c9f25bc544d
ORCID for P. Stoodley: ORCID iD orcid.org/0000-0001-6069-273X

Catalogue record

Date deposited: 09 Jun 2010 09:06
Last modified: 09 Jan 2022 03:32

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Contributors

Author: P. Stoodley ORCID iD
Author: I. Dodds
Author: D. De Beer
Author: H. Lappin Scott
Author: J.D. Boyle

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