Microbiology in nuclear waste management

Transcription

1 Microbiology in nuclear waste management KYT2018 seminar Minna Vikman, Hanna Miettinen, Leena Carpén, VTT Riikka Kietäväinen, GTK

2 Projects Microbial sulphur cycle in final nuclear waste repository conditions - Geobiokierto (Miettinen, VTT) Microbiology related to geological disposal of low- and intermediate level waste - MAKERI (Vikman, VTT) Microbially induced corrosion of low and intermediate level radioactive waste - CORLINE (Carpén, Rajala, VTT) Figure:TVO Nutrients, energy and gases in bedrock biosphere - RENGAS (Kietäväinen, GTK) Microbiology is also studied in Coordinated project Capsule (BASUCA, MICOR) Figure: Posiva

3 Microbes Microbes can be found everywhere Deep subsurface environments Have been around 3.8 billions years (long before plants and animals) Microbes Where microbes come from: Indigenous microbes Groundwater Bedrock Man-introduced microbes Bacteria Archaea Fungi Most microbes µm Live in communities 11/02/2019 VTT beyond the obvious 3

4 Microbes in final repositories Produce gas (methane, CO 2 ) Produce corrosive components (e.g. sulphide, acetate) Enhance/participate corrosion process Produce metabolites that form complexants with radionuclides Change geochemical environment in repository (e.g. ph) Change redox state of the radionuclides Can affect the performance of engineered barrier materials Can influence the solubility, the sorption and the mobility of radionuclides Photo: Posiva

5 What microbes need? What microbes need? Space to grow Water availability Major nutrients: C,H,N,O,P,S Minor nutrients: e.g Fe, Ca, Mg, Mn Available microbial energy: results of oxidation and reduction Certain environmental conditions (ph, temperature etc.) What can we do? Restrict space: porosity >0.2 µm Lower water availability Limit supply of major and minor nutrients (diffusion) Create extreme physicochemical conditions (high ph, temperature etc.) Control microbial respiration to limit unbeneficial microbes Information about microbial communities needed 11/02/2019 VTT beyond the obvious 5

6 Microbes can adapt to extreme conditions: Temperature ph Salinity Pressure Radiation Water content Nutrient concentration Toxic compounds Some bacteria can form spores that survive extreme conditions for long time 11/02/2019 VTT beyond the obvious 6

7 Geology Microbiology Groundwater Bedrock Chemistry Bentonite Copper Structural analytics Steel Waste Photo: Posiva 11/02/2019 VTT beyond the obvious Photos: VTT and commons wikimedia 7

8 Geobiokierto Microbial sulphur cycle in final nuclear waste repository conditions Hanna Miettinen Minna Vikman Mirva Pyrhönen Michał Matusewicz Malin Bomberg

9 Geobiokierto project had two aims: To study microbiological mechanisms related to sulphide formation in final nuclear waste repository conditions Literature review: To evaluate the influence of microbes and their metabolites on physical structure of bentonite and its performance 11/02/2019 VTT beyond the obvious 9

10 35 S tracer method for analysing microbial sulphate reduction in deep groundwater 35 S tracer method for microbial sulphate reduction measurement developed 300 x more sensitive than the chemical method Sulphate reduction detected also in deep groundwaters with low concentration of sulphate Sulphate reduction rate varies between groundwaters Sulphate reduction rate is affected by addition of depleted electron donors and acceptors Master thesis on the method 11/02/2019 VTT beyond the obvious 10

11 Long-term microbial experiment with bentonite 2015 started with worst case scenario conditions Wyoming type bentonite, Olkiluoto water, slurry, low concentration of electron donors for microbes, sterilised control samples Anaerobic and aerobic start Yearly studies of Chemistry (liquid phase: aluminium, silicon, sulphate, iron; bentonite: CEC) Gas phase composition (N 2, O 2, CO 2, CH 4, H 2 ) Microbiology (ATP, sulphate reduction 35 S) Bentonite is challenging material to study Method to extract DNA from bentonite developed Suitable methods to analyse bentonite structure screened for Atomic force microscopy of bentonite (AFM) and HR-TEM 11/02/2019 VTT beyond the obvious 11

12 Main results from long-term experiment Microbial activity Generally microbes not very active based on (energy molecule ATP levels) Sulphate reduction ongoing in the anaerobic samples after one year Microbial activity seen as changes in gas concentrations (O 2, H 2 ) Levels microbes mostly at the same level or slightly decreased as a function of time Energy for microbes levelling out due to the small sample volume (80 ml) not happening in real conditions No changes in bentonite structure after two years of microbial storage - If changes had been detected - a big problem Experiment will be continued in KYT energy additions 11/02/2019 VTT beyond the obvious 12

13 MAKERI Microbiology related to geological disposal of low- and intermediate level waste Minna Vikman Mirva Pyrhönen

14 Aims of MAKERI project: To study the influence of microbial activity on microbiological degradation of low- and intermediate level waste, gas generation and performance engineered barrier systems Research environments Gas Generation Experiment (GGE) in VLJ repository, Olkiluoto Simulation experiments in the laboratory LLW Bitumen Gaseous radionuclides (e.g. 14 C) can be transported to the biosphere in the form of methane gas ( 14 CH 4 ) Development of overpressure in the repository Disruption of the engineered barrier system (EBS) Increase groundwater flow rates Produced gas in the geosphere can enhance the activity of microbial communities 11/02/2019 VTT beyond the obvious 14

15 Microbial activity and ph Extreme alkaline ph (ph > 12.5) limits microbial activity in repository conditions. Microbial activity can reduce ph especially in heterogenous chemical conditions.

16 Heterogenous chemical conditions in the GGE In the beginning of the experiment chemical conditions were heterogeneous in different compartments of the experiment Bottom level /Tank lid level Tank water / Inside drums ph and dissolved organic carbon (DOC) ph 7-8 ph 11 optimal niches for microbial activity gas generation started after 1 year More methanogens and SRBs were detected in bottom level of the tank on the basis of quantitative PCR

17 Gas generation Generation of methane require ph within certain limit values and a low sulphate concentration. Groundwater flow to the LLW repository can reduce the gas generation (activation of sulphate reducers) Hydrogen formed as a result of corrosion of metals and in biodegradation was utilized in microbial in situ processes, and hydrogen was not detected in the gas phase. Simulation experiment in the laboratory

18 Biodegradation of bitumen in final repository conditions The most relevant organic components in ILW in Finland are ion exchange resins and bitumen used for encapsulation. Organic part of ILW can degrade microbiologically, chemically, by radiation, or by combination of them. Bitumen contains aliphatic, aromatic and heterocyclic hydrocarbons, which are shown to be biodegradable at least in certain environmental conditions. No significant microbiological degradation of bitumen was observed Microbial acitivity was slighly increased in bitumen containing samples

19 Results and achievements New information about microbiological degradation of LLW and about factors affecting the gas generation Microbiological monitoring of GGE Simulation experiments in the laboratory with LLW and bitumen International co-operation with National Nuclear Laboratory in modelling of GGE Two manuscripts Presentation in Goldschmidt 2017-conference 11/02/2019 VTT beyond the obvious 19

20 CORLINE Microbially induced corrosion of low and intermediate level radioactive waste Leena Carpén, Pauliina Rajala, Elisa Isotahdon VTT

21 Aims of CORLINE project 1. Development of reliable online in-situ methods for measuring corrosion and water chemistry in drill holes 2. Determination of microbial action and it s effect on corrosion rate and mechanism of decommissioning metal waste in final repository conditions of Finland 3. Exploitation the more throughout analysis of formed corrosion products and gases in order to improve the understanding of microbially induced corrosion 11/02/2019 VTT beyond the obvious 21

22 Examples of corrosion studies Long term electrochemical studies on carbon steel and stainless steels with and without bacteria (acetogens, methanogens, SRB) Instantaneous corrosion rates in different environments (vs. average rates by weight loss) Corrosion mechanisms Sample characterizations after the tests Biofilm Corrosion products 11/02/2019 VTT beyond the obvious 22

23 Gas analysis and microbiology Gas detection (CH 4, CO 2 ) in co-operation with Helsinki University Metagenomics of drill hole water Sequencing of biofilm qpcr 11/02/2019 VTT beyond the obvious 23

24 Microbes and corrosion product on surface of carbon steel exposed to groundwater with SRB and acetogen amendment (left). The number of bacterial 16S rrna and dsrb genes and archaeal 16S rrna genes per cm 2 or ml estimated by qpcr (middle). The average corrosion rates of carbon steel with different amendments (right). 11/02/2019 VTT beyond the obvious 24

25 Field studies in VLJ cave In-situ measurements in drill holes Electrochemical measurements for online measurements of steel sample behaviour OsmoSampler collecting water samples water chemistry connected to corrosion rates 11/02/2019 VTT beyond the obvious 25

26 Results and achievements Corrosion evaluation for carbon steel and the most commonly used stainless steel grades (304 and 316) in relevant microbial environments were done Corrosive effect of different microbes discovered Results may be used to estimate the behaviour of decommissioning waste VLJ cave sample metagenomics relevant metabolism routes were found In-situ measurements in drill holes were successful International co-operation with DCO in metagenomics, Jamstec: Hybridized Chain Reaction Fluorescent in situ Hybridization (HCR-FISH), Stirling University (Mössbauer analysis) 11/02/2019 VTT beyond the obvious 26

27 RENGAS Nutrients, energy and gases in bedrock biosphere Riikka Kietäväinen Geological Survey of Finland Espoo Bedrock Construction and Site Assessment Unit

28 WP1: Method development Monitoring of spontaneous gas flux from the bedrock at Outokumpu Correlation between gas composition and solid earth tides Potential as a monitoring tool in the repository: changes in gas flux can indicate changes in e.g. fracture density, deterioration of engineered barriers Riikka Kietäväinen Métivier et al. EPSL 2009

29 Kietäväinen, 2017 PhD Thesis WP2: Evolution and residence times of bedrock groundwaters South Africa Canada Fennoscandia Model of deep groundwater evolution Compilation and new determinations of groundwater residence times Pyhäsalmi mine, 160 Ma Better understanding of time scales of (bio)geochemical processes, long term safety Riikka Kietäväinen

30 WP3: Sulphur in deep bedrock groundwaters Study of sulphide production using stable sulphur isotopes Observed isotope fractionation consistent with microbial sulphate reduction Differences between the sites could reflect differences in the SRB populations (complete vs. incomplete oxidation of organic carbon or use of H 2 as an electron donor) Sulphate = bulk sulphide Importance for corrosion Riikka Kietäväinen Ion exchange resins used to separate sulphur from the samples

31 Diagram after Etiope 2017 WP4: Carbon in deep bedrock groundwaters Abiotic isotope signal in methane Could be also due to carbon limitation and isolation In the upper 1 km depth considerable potential for microbial methanogenesis High and continous CH 4 flux observed (two drill holes, total flux l/day) 14 C mobilisation, microbial activity Depth Methanogens Residence time Microbial CH 4 Microbial CH 4 Oxidation: Carbon limitation: Mixing: Riikka Kietäväinen Purkamo et al. 2016, methanogenesis rate: 2 Colwell et al. 2008, 6,2*10-12 mmol/cell/a, 3 Simkus et al. 2016, 1,5*10-11 mmol/cell/a

32 Depth (m) WP5: Synthesis of biogeochemical reactions in bedrock groundwater Thermodynamic viewpoint Case study: Outokumpu Deep Drill Hole Direction (Gibbs energies, ΔG r ) Energy densities (E r ) take the limiting compounds into account Methanogenesis from graphite and H 2 the most energetically favourable reaction Sulphate reduction is limited by sulphate availability Energy densities are low (1/1000 of those find at ocean floor sediments) Riikka Kietäväinen

33 Dissertations and thesis Pauliina Rajala, PhD thesis: Microbially-induced corrosion of carbon steel in a geological repository environment (2017), VTT Science, 155 p. Kietäväinen Riikka, Deep Groundwater Evolution at Outokumpu, Eastern Finland: From Meteoric Water to Saline Gas- Rich Fluid. PhD Thesis, University of Helsinki, Geological Survey of Finland Special Publication 97, 150 p. Anna Manninen, Biological sulphate reduction potential in waters from the geological repository site for nuclear waste disposal in Olkiluoto, Finland. Heikkinen Nina, Kaasujen liukoisuus Outokummun syväkairareiän suolaisessa pohjavedessä. MSc thesis, University of Helsinki, Department of Geosciences and Geography, 77 p.

34 Publications Bomberg, M., Raulio, M., Jylhä, S., Mueller, C.W., Höschen, C., Rajala, P., Purkamo, L., Kietäväinen, R., Ahonen, L. Itävaara M., CO 2 and carbonate as substrate for the activation of the microbial community in 180 m deep bedrock fracture fluid of Outokumpu Deep Drill Hole, Finland. AIMS Microbiology 3, Carpén, L., Rajala, P., Bomberg, M Microbially Induced Corrosion in Deep Bedrock. Advanced Materials Research Vol (2015) pp Kietäväinen R., Ahonen L., Niinikoski P., Nykänen H., Kukkonen I.T., Abiotic and biotic controls on methane formation down to 2.5 km depth within the Precambrian Fennoscandian Shield. Geochimica et Cosmochimica Acta 202, Miettinen, H., Kietäväinen, R., Sohlberg, E., Numminen, M., Ahonen, L., Itävaara, M Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland. Frontiers in Microbiology. 6:1203. doi: /fmicb Miettinen, H S-tracer method for analyzing microbial sulfur compound cycling in oligotrophic anoxic groundwater habitat. VTT Technology 249. Miettinen, H., Bomberg, M., Vikman, M Acetate activates deep subsurface fracture fluid microbial communities in Olkiluoto, Finland. Geosciences. 8(11), 399. doi.org/ /geosciences /02/2019 VTT beyond the obvious 34

35 Publications Nuppunen-Puputti M., Purkamo L., Kietäväinen R., Nyyssönen M., Itävaara M., Ahonen L., Kukkonen I., Bomberg M., Rare biosphere archaea assimilate acetate in Precambrian terrestrial subsurface at 2.2 km depth. Geosciences 8, 418, doi: /geosciences Purkamo L., Kietäväinen R., Miettinen H., Sohlberg E., Kukkonen I., Itävaara M., Bomberg M., Diversity and functionality of archaeal, bacterial and fungal communities in deep Archaean bedrock groundwater. FEMS Microbiology Ecology 94, doi: /femsec/fiy116 Rajala, P., Bomberg, M. Vepsäläinen, M., Carpén, L., Microbial fouling and corrosion of carbon steel in alkaline deep groundwater, Biofouling, 33(2): Small, J., Nykyri, M., Vikman, M., Itävaara, M., Heikinheimo, L., The biogeochemistry of gas generation from low-level nuclear waste: Modelling after 18 years study under in situ conditions, Applied Geochemistry. Elsevier. Vol. 84 (2017), Vikman, M., Itävaara, M., Carpén, L., Matala- ja keskiaktiivisen ydinjätteen loppusijoituksen mikrobiologiset riskit Suomessa, VTT Technology 273, 41 s. ISBN Vikman, M., Marjamaa, K., Itävaara, M., Nykyri, M., Small, J., Paaso, N., Microbial degradation of low-level radioactive waste in repository conditions, presentation, Goldschmidt 2017, August 2017, Paris, France European Association of Geochemistry. 11/02/2019 VTT beyond the obvious 35

36 Acknowledgements KYT Finnish Research Program on Nuclear Waste Management Posiva Oy Teollisuuden Voima Oyj Horizon 2020 project Microbiology In Nuclear waste Disposal (MIND) through funding from the Euratom research and training programme under Grant Agreement no Istituto Nazionale di Geofisica e Vulcanologia (INGV) Rome/Giuseppe Etiope Deep Carbon Observatory (DCO) First Quantum Minerals/Pyhäsalmi Mine Callio Lab International Continental Scientific Drilling Program (ICDP) GFZ Potsdam KYT2018 THEBES project