Tracer measurements reveal experimental evidence of biofilm consolidation

Casey, Eoin

doi:10.1002/bit.21456

Cited by 16 publications

(11 citation statements)

References 40 publications

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“…In cases where the normal stresses are great enough, the biofilm undergoes compression because of its porous structure. This compression actually refers to biofilm consolidation, phenomenon that has been previously described by Laspidou and Rittmann (2004a); Alpkvist et al, 2006;Casey, 2007. It increases the internal strength, possibly explaining why this basal layer is much more resistant to high shear stress.…”

Section: 2mentioning

confidence: 89%

Effect of shear stress and growth conditions on detachment and physical properties of biofilms

Paul¹,

Ochoa²,

Péchaud³

et al. 2012

Water Research

173

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Section: 2mentioning

confidence: 89%

Effect of shear stress and growth conditions on detachment and physical properties of biofilms

Paul¹,

Ochoa²,

Péchaud³

et al. 2012

Water Research

173

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“…biofilm thickness) should be carried out under shear stress in order to produce representative results. Casey [6] proposed compaction as a mechanism contributing to the structural realignment of the biofilm under high shear force. Compaction is defined as the increase in density and the decrease in porosity of a biofilm, resulting in a thickness decrease of the biofilm.…”

Section: Introductionmentioning

confidence: 99%

Compaction and relaxation of biofilms

Linares

Wexler²,

Bucs

et al. 2015

Desalination and Water Treatment

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A B S T R A C TOperation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s −1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m −2 h −1 . The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m −2 h −1 while the biofilm thickness increased again after restoring the original flux of 20 L m −2 h −1 , indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more compact biofilms with a higher hydraulic resistance.

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“…While de‐levelling of microbial mats has yet to be studied in detail, the observation of biofilm compression and density increase without complete detachment from solid surfaces, under laboratory conditions, is consistent with field observations post‐TC Olwyn. Hydrodynamic compression of biofilms resulted in permanent structural changes, including density changes (Casey, 2007) which decrease porosity and increased hydraulic resistance (Picioreanu et al, 2018).…”

Section: Discussion: Impacts Of Tc Olwynmentioning

confidence: 99%

Impacts of Severe Tropical Cyclone Olwyn and the biogeomorphic response, Hamelin Pool, Shark Bay, Western Australia

Morris

Fearns

et al. 2022

The Depositional Record

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Storm disturbance and recovery of the peritidal benthic microbial ecosystem occurs as part of the natural climate regime in Shark Bay. However, tropical cyclone and winter storm frequency and intensity are known to be changing due to climate forcing. Presented here is an analysis of the biogeomorphic response of the benthic microbial ecosystem within the intertidal to upper subtidal zone and the beach face coquina deposits of Hamelin Pool, to the passage of Category 3 Severe Tropical Cyclone Olwyn (13 March 2015). Storm effects (initial response to 40 days post‐event) include: erosional sculpting of sediments, mats and structures; deposition and winnowing of sediments; accumulation of mucilaginous products into flocs, slurries and sludges; along with limited development of new coquina deposits in the beach face. Medium (15 months) term observations include: mat recovery and changes with transformation of mucilage deposits into new subtidal gelatinous mats, intertidal transitional mats and low‐elevation microbial structures. Observations suggest that this disturbance had both positive (the floc‐to‐mat biogeomorphic storm response) and negative feedbacks (enhanced bioturbation), which impact the development of stromatolite forming microbial mats and microbialite structures.

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Tracer measurements reveal experimental evidence of biofilm consolidation

Cited by 16 publications

References 40 publications

Effect of shear stress and growth conditions on detachment and physical properties of biofilms

Effect of shear stress and growth conditions on detachment and physical properties of biofilms

Compaction and relaxation of biofilms

Impacts of Severe Tropical Cyclone Olwyn and the biogeomorphic response, Hamelin Pool, Shark Bay, Western Australia

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