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Induced Polarisation (IP) laboratory measurements on E. coli sand mixtures

Martin, Tina LU and Paul, Catherine J. LU (2019) 79th annual conference of the German Geophysical Society (DGG),
Abstract
The aim of the MIRACHL project is the characterisation and monitoring of insitu
remediation of chlorinated hydrocarbon contamination using an interdisciplinary approach and geophysical methods, such as DCIP (direct current induced polarisation) to investigate the remediation process.
To interpret these geophysical field IP data, lab investigations with different kinds of bacteria are necessary to assess the sensitivity of the methods for these specific applications. A first experiment was conducted with E. coli bacteria. Bacteria were grown together with a rich source of nutrients (Luria Bertani
broth LB) and mixed in different flasks with sterilised Ottawa sand. These bacteria-sand-mixtures were continuously shaken (30°C, 80... (More)
The aim of the MIRACHL project is the characterisation and monitoring of insitu
remediation of chlorinated hydrocarbon contamination using an interdisciplinary approach and geophysical methods, such as DCIP (direct current induced polarisation) to investigate the remediation process.
To interpret these geophysical field IP data, lab investigations with different kinds of bacteria are necessary to assess the sensitivity of the methods for these specific applications. A first experiment was conducted with E. coli bacteria. Bacteria were grown together with a rich source of nutrients (Luria Bertani
broth LB) and mixed in different flasks with sterilised Ottawa sand. These bacteria-sand-mixtures were continuously shaken (30°C, 80 RPM) until defined endpoints (within 21 days) when the mixtures were harvested and packed in a
4-point sample holder to measure SIP (spectral induced polarisation), TDIP (time-domain induced polarisation) and SP (self potential) under laboratory conditions. The same procedure was repeated with only the media-sand
mixture to exclude any influences from just the nutrient and with water-sand
mixtures.
The results show a slightly increase in phase and a decrease in resistivity after several days with a decrease in phase that appears to coincide with dieoff
of the bacteria. Resistivity in general was very low (between 310
m) due to the highly conductive LB-media containing 5 g/L NaCl. As a result, the phase effects are very small too. The positive phase which could be observed for the E. coli measurements was surprising and is not yet understood. As expected, the water-sand mixtures showed almost no phase shift and slightly higher
resistivity values. The influence of the nutrients is very small and results in a slightly lower resistivity than the E. coli-sand mixtures. The SP measurements show no clear tendency, but this is most likely due to limitations in the sample holder. The TDIP data needs to be further processed but the resistivity values are in accordance with the SIP results. Scanning electron microscope (SEM) images showed E. coli bacteria attached to the sand grains which could modify the grain surface (e.g. increasing the surface area and/or form a biofilm) and impact the IP
measurements. In future, to support these observations with quantitative comparisons, the number of bacteria present in the sand will be determined using quantitative polymerase chain reaction (qPCR) to detect bacterial DNA (deoxyribonucleic acid). (Less)
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author
organization
publishing date
type
Contribution to conference
publication status
published
subject
conference name
79th annual conference of the German Geophysical Society (DGG),
conference location
Braunschweig, Germany
conference dates
2019-03-04 - 2019-06-06
project
Linking Time Domain Induced Polarization (TDIP) and Spectral IP (SIP) to characterise the subsurface for groundwater management and protection purposes
Characterisation and monitoring of in-situ remediation of chlorinated hydrocarbon contamination using an interdisciplinary approach
language
English
LU publication?
yes
id
2e236609-0c87-437e-b617-5ae5ed3d7e02
date added to LUP
2019-06-03 09:52:37
date last changed
2019-06-11 09:50:13
@misc{2e236609-0c87-437e-b617-5ae5ed3d7e02,
  abstract     = {The aim of the MIRACHL project is the characterisation and monitoring of insitu<br/>remediation of chlorinated hydrocarbon contamination using an interdisciplinary approach and geophysical methods, such as DCIP (direct current induced polarisation) to investigate the remediation process.<br/>To interpret these geophysical field IP data, lab investigations with different kinds of bacteria are necessary to assess the sensitivity of the methods for these specific applications. A first experiment was conducted with E. coli bacteria. Bacteria were grown together with a rich source of nutrients (Luria Bertani<br/>broth LB) and mixed in different flasks with sterilised Ottawa sand. These bacteria-sand-mixtures were continuously shaken (30°C, 80 RPM) until defined endpoints (within 21 days) when the mixtures were harvested and packed in a<br/>4-point sample holder to measure SIP (spectral induced polarisation), TDIP (time-domain induced polarisation) and SP (self potential) under laboratory conditions. The same procedure was repeated with only the media-sand<br/>mixture to exclude any influences from just the nutrient and with water-sand<br/>mixtures.<br/>The results show a slightly increase in phase and a decrease in resistivity after several days with a decrease in phase that appears to coincide with dieoff<br/>of the bacteria. Resistivity in general was very low (between 310<br/>m) due to the highly conductive LB-media containing 5 g/L NaCl. As a result, the phase effects are very small too. The positive phase which could be observed for the E. coli measurements was surprising and is not yet understood. As expected, the water-sand mixtures showed almost no phase shift and slightly higher<br/>resistivity values. The influence of the nutrients is very small and results in a slightly lower resistivity than the E. coli-sand mixtures. The SP measurements show no clear tendency, but this is most likely due to limitations in the sample holder. The TDIP data needs to be further processed but the resistivity values are in accordance with the SIP results. Scanning electron microscope (SEM) images showed E. coli bacteria attached to the sand grains which could modify the grain surface (e.g. increasing the surface area and/or form a biofilm) and impact the IP<br/>measurements. In future, to support these observations with quantitative comparisons, the number of bacteria present in the sand will be determined using quantitative polymerase chain reaction (qPCR) to detect bacterial DNA (deoxyribonucleic acid).},
  author       = {Martin, Tina and Paul, Catherine J. },
  language     = {eng},
  title        = {Induced Polarisation (IP) laboratory measurements on E. coli sand mixtures},
  url          = {https://lup.lub.lu.se/search/ws/files/65396650/Poster_Lab_DGG.pdf},
  year         = {2019},
}