The effects of the physical properties of highly compacted smectitic clay (bentonite) on the culturability of indigenous microorganisms

Stroes-Gascoyne, S.; Hamon, C.J.; Maak, Peter; Russell, S.B.

doi:10.1016/j.clay.2008.06.010

Cited by 74 publications

(60 citation statements)

References 18 publications

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“…The main finding shows that viable microorganisms are present in bentonite and, depending on the density of the clay in the module, a fraction of those microorganisms remain viable, which is in line with previous work by others, (Stroes-Gascoyne et al 2010). However, as expected at higher densities, a smaller fraction can grow or even survive (i.e.…”

Section: Ic-a Experimentssupporting

confidence: 78%

Corrosion of carbon steel in clay environments relevant to radioactive waste geological disposals, Mont Terri rock laboratory (Switzerland)

Necib¹,

Diomidis

Keech

et al. 2017

Swiss J Geosci

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Carbon steel is widely considered as a candidate material for the construction of spent fuel and high-level waste disposal canisters. In order to investigate corrosion processes representative of the long term evolution of deep geological repositories, two in situ experiments are being conducted in the Mont-Terri rock laboratory. The iron corrosion (IC) experiment, aims to measure the evolution of the instantaneous corrosion rate of carbon steel in contact with Opalinus Clay as a function of time, by using electrochemical impedance spectroscopy measurements. The Iron Corrosion in Bentonite (IC-A) experiment intends to determine the evolution of the average corrosion rate of carbon steel in contact with bentonite of different densities, by using gravimetric and surface analysis measurements, post exposure. Both experiments investigate the effect of microbial activity on corrosion. In the IC experiment, carbon steel showed a gradual decrease of the corrosion rate over a period of 7 years, which is consistent with the ongoing formation of protective corrosion products. Corrosion product layers composed of magnetite, mackinawite, hydroxychloride and siderite with some traces of oxidising species such as goethite were identified on the steel surface. Microbial investigations revealed thermophilic bacteria (sulphate and thiosulphate reducing bacteria) at the metal surface in low concentrations. In the IC-A experiment, carbon steel samples in direct contact with bentonite exhibited corrosion rates in the range of 2 lm/year after 20 months of exposure, in agreement with measurements in absence of microbes. Microstructural and chemical characterisation of the samples identified a complex corrosion product consisting mainly of magnetite. Microbial investigations confirmed the limited viability of microbes in highly compacted bentonite.

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Section: Ic-a Experimentssupporting

confidence: 78%

Corrosion of carbon steel in clay environments relevant to radioactive waste geological disposals, Mont Terri rock laboratory (Switzerland)

Necib¹,

Diomidis

Keech

et al. 2017

Swiss J Geosci

View full text Add to dashboard Cite

show abstract

“…The finding, which is in line with previous work [13], shows that viable microorganisms are present in bentonite and, depending on the density of the clay in the module, a fraction of those microorganisms remain viable. As expected, at higher densities, a smaller fraction survives, while at lower densities, a higher fraction survives.…”

supporting

confidence: 81%

Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

Leupin

Bernier‐Latmani

Bagnoud

et al. 2017

Mont Terri Rock Laboratory, 20 Years

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A long-term in situ corrosion experiment is ongoing in the Mont Terri Underground Research Laboratory in Switzerland to (i) measure the in situ corrosion behaviour of carbon steel in compacted bentonite under simulated repository conditions, (ii) study the effect of the bentonite buffer density on microbial activity and microbially influenced corrosion and (iii) study the effect of welding on the corrosion rate. Carbon steel corrosion coupons, with and without welds, were surrounded by compacted bentonite with a range of dry densities and mounted in modules allowing free exchange with the local anoxic groundwater. After about 20 months of exposure, corrosion coupons and bentonite were sampled. A complex corrosion product was identified, consisting predominantly of magnetite. The bentonite adjacent to the metal was finer grained, more dispersed and enriched in iron. Aerobic, anaerobic and sulphate-reducing bacteria were identified both in the porewater surrounding the modules and in the bentonite. ARTICLE HISTORY

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“…Microbial implications on the performance of the EBS in DGR have been the subject of considerable study ( Stroes-Gascoyne et al., 2006 , 2010 ; Wang and Francis, 2005 ; Humphreys et al., 2010 ; Mulligan et al., 2009 ; Behrends et al., 2012 ; Pedersen, 2010 , 2013 ; Pedersen et al., 2012 ; Lopez-Fernandez et al., 2015 ; Stone et al., 2016 ). As genuine bio-catalysts, bacteria are capable of vigorously modifying their environments through their growth and metabolite production.…”

Section: Introductionmentioning

confidence: 99%

Bacterial diversity and production of sulfide in microcosms containing uncompacted bentonites

Grigoryan

Jalique

Medihala

et al. 2018

Heliyon

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AimsThis study examined the diversity and sulfide-producing activity of microorganisms in microcosms containing commercial clay products (e.g., MX-80, Canaprill and National Standard) similar to materials which are currently considered for use in the design specifications for deep geologic repositories (DGR) for spent nuclear fuel.Methods and resultsIn anoxic microcosms incubated for minimum of 60 days with 10 g l-1 NaCl, sulfide production varied with temperature, electron donor and bentonite type. Maximum specific sulfide production rates of 0.189 d−1, 0.549 d−1 and 0.157 d−1 occurred in lactate-fed MX-80, Canaprill and National Standard microcosms, respectively. In microcosms with 50 g l-1 NaCl, sulfide production was inhibited. Denaturing gradient gel electrophoresis (DGGE) profiling of microcosms revealed the presence of bacterial classes Clostridia, Bacilli, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, Sphingobacteriia and Erysipelotrichia. Spore-forming and non-spore-forming bacteria were confirmed in microcosms using high-throughput 16S rRNA gene sequencing. Sulfate-reducing bacteria of the genus Desulfosporosinus predominated in MX-80 microcosms; whereas, Desulfotomaculum and Desulfovibrio genera contributed to sulfate-reduction in National Standard and Canaprill microcosms.ConclusionsCommercial clays microcosms harbour a sparse bacterial population dominated by spore-forming microorganisms. Detected sulfate- and sulfur-reducing bacteria presumably contributed to sulfide accumulation in the different microcosm systems.Significance and impact of studyThe use of carbon-supplemented, clay-in-water microcosms offered insights into the bacterial diversity present in as-received clays, along with the types of metabolic and sulfidogenic reactions that might occur in regions of a DGR (e.g., interfaces between the bulk clay and host rock, cracks, fissures, etc.) that fail to attain target parameters necessary to inhibit microbial growth and activity.

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The effects of the physical properties of highly compacted smectitic clay (bentonite) on the culturability of indigenous microorganisms

Cited by 74 publications

References 18 publications

Corrosion of carbon steel in clay environments relevant to radioactive waste geological disposals, Mont Terri rock laboratory (Switzerland)

Corrosion of carbon steel in clay environments relevant to radioactive waste geological disposals, Mont Terri rock laboratory (Switzerland)

Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

Bacterial diversity and production of sulfide in microcosms containing uncompacted bentonites

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