The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Holger Weiß - One of the best experts on this subject based on the ideXlab platform.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken. 2 Objectives To obtain a more detailed image of a subsurface NAPL plume and, hence, to facilitate Remediation measures that are best suited for the site in question, a denser network of monitoring points is desirable. The aim of the investigation described in this paper was therefore to develop a new detection method for subsurface NAPL contamination, which is based on an easily accessible indicator for NAPLs rather than on the analysis of soil and groundwater samples taken at the site. Based on the good solubility of radon in NAPLs, the idea was put forward that subsurface NAPL contamination should have an influence on the natural radon concentration of the soil gas. Provided this effect is significant, it would be possible to carry out a straightforward radon survey on an appropriate sampling grid covering the suspected site and thus enabling the NAPL contamination to be detected by the localization of anomalous low radon concentrations in the soil. The overall aim of the investigation was to assess the general suitability of the soil-gas radon concentration as an indirect tracer for NAPL contamination in the ground. 3 Methods The partitioning coefficient K_NAPL/air is one of the most influential parameters governing the decrease of the radon concentration in the soil gas in the presence of a subsurface NAPL contamination. Since NAPL mixtures such as gasoline, diesel fuel and paraffin are among the most important NAPLs regarding Remediation activities, laboratory experiments were performed to determine the radon-partitioning coefficient for these three NAPL mixtures. Field experiments were carried out as well. The aim of the field experiments was to test the use of the soil-gas radon concentration as a tracer for NAPL contamination on-site. For the field experiments, each site was covered with a suitable grid of soil gas sampling points. Finally, the lateral radon distribution pattern achieved on each of the sites was compared to the respective findings of the earlier research performed by conventional means. 4 Results and Discussion The results of the laboratory experiments clearly show a very strong affinity of radon to the NAPL mixtures examined. The partitioning coefficients achieved correspond to those published for pure NAPLs (Clever 1979) and are thus in the expected range. The results of the field experiments showed that the minimum radon concentrations detected match the respective NAPL plumes traced previously. 5 Conclusions Both the results of the lab experiments and the on-site findings demonstrate that the soil-gas radon concentration can be used as an indicator for subsurface NAPL contamination. The investigation showed that NAPL-contaminated soil volumes give rise to anomalous low soil-gas radon concentrations in the close vicinity of the contamination. The reason for this decrease in the soil-gas radon concentration is the good solubility of radon in NAPLs, which enables the NAPLs to accumulate and ‘trap’ part of the radon available in the soil pores. 6 Recommendations and Outlook Further research is required into contamination with rather volatile NAPLs such as BTEX. Further research is also needed to examine whether it is possible to not only localize a NAPL plume, but also to obtain some quantitative information about the subsurface NAPL contamination. The authors also believe that additional investigations should be carried out to study the ability of the method to not just localize a NAPL contamination, but also to monitor on-site, clean-up measures.
Michael Schubert - One of the best experts on this subject based on the ideXlab platform.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken. 2 Objectives To obtain a more detailed image of a subsurface NAPL plume and, hence, to facilitate Remediation measures that are best suited for the site in question, a denser network of monitoring points is desirable. The aim of the investigation described in this paper was therefore to develop a new detection method for subsurface NAPL contamination, which is based on an easily accessible indicator for NAPLs rather than on the analysis of soil and groundwater samples taken at the site. Based on the good solubility of radon in NAPLs, the idea was put forward that subsurface NAPL contamination should have an influence on the natural radon concentration of the soil gas. Provided this effect is significant, it would be possible to carry out a straightforward radon survey on an appropriate sampling grid covering the suspected site and thus enabling the NAPL contamination to be detected by the localization of anomalous low radon concentrations in the soil. The overall aim of the investigation was to assess the general suitability of the soil-gas radon concentration as an indirect tracer for NAPL contamination in the ground. 3 Methods The partitioning coefficient K_NAPL/air is one of the most influential parameters governing the decrease of the radon concentration in the soil gas in the presence of a subsurface NAPL contamination. Since NAPL mixtures such as gasoline, diesel fuel and paraffin are among the most important NAPLs regarding Remediation activities, laboratory experiments were performed to determine the radon-partitioning coefficient for these three NAPL mixtures. Field experiments were carried out as well. The aim of the field experiments was to test the use of the soil-gas radon concentration as a tracer for NAPL contamination on-site. For the field experiments, each site was covered with a suitable grid of soil gas sampling points. Finally, the lateral radon distribution pattern achieved on each of the sites was compared to the respective findings of the earlier research performed by conventional means. 4 Results and Discussion The results of the laboratory experiments clearly show a very strong affinity of radon to the NAPL mixtures examined. The partitioning coefficients achieved correspond to those published for pure NAPLs (Clever 1979) and are thus in the expected range. The results of the field experiments showed that the minimum radon concentrations detected match the respective NAPL plumes traced previously. 5 Conclusions Both the results of the lab experiments and the on-site findings demonstrate that the soil-gas radon concentration can be used as an indicator for subsurface NAPL contamination. The investigation showed that NAPL-contaminated soil volumes give rise to anomalous low soil-gas radon concentrations in the close vicinity of the contamination. The reason for this decrease in the soil-gas radon concentration is the good solubility of radon in NAPLs, which enables the NAPLs to accumulate and ‘trap’ part of the radon available in the soil pores. 6 Recommendations and Outlook Further research is required into contamination with rather volatile NAPLs such as BTEX. Further research is also needed to examine whether it is possible to not only localize a NAPL plume, but also to obtain some quantitative information about the subsurface NAPL contamination. The authors also believe that additional investigations should be carried out to study the ability of the method to not just localize a NAPL contamination, but also to monitor on-site, clean-up measures.
Adrian Rojo - One of the best experts on this subject based on the ideXlab platform.
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Electrokinetic Remediation of Copper Mine Tailings: Evaluating Different Alternatives for the Electric Field
Electrokinetics Across Disciplines and Continents, 2020Co-Authors: Henrik K. Hansen, Adrian Rojo, Claudia Gutiérrez, Pernille Erland Jensen, Lisbeth M OttosenAbstract:Due to the magnitude of the mining activity in Chile, it becomes necessary to find solutions to mitigate the impact of mining waste on the environment. One method that could be suitable for Remediation of mining wastes is the use of electric fields for the removal of metals, the so-called electrochemical Remediation: electrokinetic or electrodialytic Remediation (EKR or EDR). Especially, metals such as copper, zinc, lead, and arsenic have been removed or concentrated when applying electric fields—and these metals are typically also found in mining waste. The use of this Remediation technology will imply the periodic application of the method in order to remove the additional soluble copper that will be generated with time. Therefore, the Remediation Action for this heterogeneous solid waste is to remove the soluble copper in the tailings and in this way making the final residue more stable.
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Electrokinetic Remediation with high frequency sinusoidal electric fields
Separation and Purification Technology, 2011Co-Authors: Adrian Rojo, Henrik K. Hansen, Milagros AgramonteAbstract:Abstract In this work an electrokinetic Remediation cell for copper mine tailings using sinusoidal electric field was analyzed. The sinusoidal electric field was obtained by applying simultaneously continuous-alternating voltages; in this work an alternating voltage of high frequency was applied. The system was tested considering the effect of: (1) the effective voltage applied to the cell and (2) the polarity reversal of the cell. According to the conditions studied in this investigation, the laboratory results showed that a high frequency sinusoidal electric field improves the EKR process, and increasing the effective voltage improves the Remediation Action, especially when a polarity inversion is present, which reduces polarization during the process.
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Electrodialytic Remediation of copper mine tailings with sinusoidal electric field
Journal of Applied Electrochemistry, 2010Co-Authors: Adrian Rojo, Henrik K. Hansen, Jorge Del CampoAbstract:In this work an electrodialytic Remediation cell for copper mine tailings using sinusoidal electric field was analyzed, in order to increase the removal efficiency. The sinusoidal electric field was obtained by applying simultaneously continuous-alternating voltages; in this work an alternating voltage of low frequency was applied. The system was tested considering the effect of: (1) the effective voltage applied to the cell, (2) the period for the alternating voltage, (3) Remediation time, and (4) copper complexing capacity of citric acid. According to the conditions studied in this investigation, the laboratory results showed that decreasing the effective voltage improves the Remediation Action, due to polarity reversal of the system, which reduces polarization during the process, but in terms of the period for the alternating voltage there is no effect. As expected the Remediation time and copper complexing capacity of citric acid improves the amount of remediated material and the Remediation Action in general.
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Electrodialytic Remediation of Copper Mine Tailing Pulps
Separation Science and Technology, 2009Co-Authors: Adrian Rojo, Henrik K. Hansen, Paula GuerraAbstract:Abstract This work compares and evaluates nine electrodialytic laboratory Remediation experiments on copper mine tailings. Experiments in the past have applied this method on moist mine tailings, but can also be applied to mine tailing-liquid mixtures. The objective of this work was the treatment of mine tailing pulps. Different parameters were analyzed, such as current density, desorbing agents, and liquid–solid ratio over non-stirred and stirred mine tailings by air suspension. The results showed that the Remediation Action is improved using mine tailings in pulps. As expected, stirring of the pulp favors the process performance. For 7 days Remediation the best results were obtained using air stirring of the pulp, citric acid addition, a liquid/solid ratio (L/S) of 4.0 [mL/g] and a current density of 0.9 [mA/cm2] reaching a 15% removal of the total copper.
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Electrodialytic Remediation of copper mine tailings using bipolar electrodes.
Journal of hazardous materials, 2009Co-Authors: Adrian Rojo, Luis CubillosAbstract:In this work an electrodialytic Remediation (EDR) cell for copper mine tailings with bipolar stainless steel plates was analyzed. The bipolar plates were inserted inside the tailings, dividing it into independent electrochemical cells or sections, in order to increase the copper removal efficiency from mine tailings. The bipolar plates design was tested on acidic copper mine tailings with a fixed: applied electric field, liquid content, initial pH, and Remediation time. The laboratory results showed that inserting bipolar plates in EDR cells improves the Remediation Action, even though the applied electric field is reduced by the electrochemical reActions on the plates. Basically three aspects favor the process: reduction of the ionic migration pathways, increase of the electrode surface, and in-situ generation of protons (H(+)) and hydroxyls (OH(-)). Furthermore, the laboratory results with citric acid addition significantly improve the Remediation Actions, reaching copper removal of up to nine times better, compared to conventional EDR experiments without any plates or citric acid addition.
Hans-christian Treutler - One of the best experts on this subject based on the ideXlab platform.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken. 2 Objectives To obtain a more detailed image of a subsurface NAPL plume and, hence, to facilitate Remediation measures that are best suited for the site in question, a denser network of monitoring points is desirable. The aim of the investigation described in this paper was therefore to develop a new detection method for subsurface NAPL contamination, which is based on an easily accessible indicator for NAPLs rather than on the analysis of soil and groundwater samples taken at the site. Based on the good solubility of radon in NAPLs, the idea was put forward that subsurface NAPL contamination should have an influence on the natural radon concentration of the soil gas. Provided this effect is significant, it would be possible to carry out a straightforward radon survey on an appropriate sampling grid covering the suspected site and thus enabling the NAPL contamination to be detected by the localization of anomalous low radon concentrations in the soil. The overall aim of the investigation was to assess the general suitability of the soil-gas radon concentration as an indirect tracer for NAPL contamination in the ground. 3 Methods The partitioning coefficient K_NAPL/air is one of the most influential parameters governing the decrease of the radon concentration in the soil gas in the presence of a subsurface NAPL contamination. Since NAPL mixtures such as gasoline, diesel fuel and paraffin are among the most important NAPLs regarding Remediation activities, laboratory experiments were performed to determine the radon-partitioning coefficient for these three NAPL mixtures. Field experiments were carried out as well. The aim of the field experiments was to test the use of the soil-gas radon concentration as a tracer for NAPL contamination on-site. For the field experiments, each site was covered with a suitable grid of soil gas sampling points. Finally, the lateral radon distribution pattern achieved on each of the sites was compared to the respective findings of the earlier research performed by conventional means. 4 Results and Discussion The results of the laboratory experiments clearly show a very strong affinity of radon to the NAPL mixtures examined. The partitioning coefficients achieved correspond to those published for pure NAPLs (Clever 1979) and are thus in the expected range. The results of the field experiments showed that the minimum radon concentrations detected match the respective NAPL plumes traced previously. 5 Conclusions Both the results of the lab experiments and the on-site findings demonstrate that the soil-gas radon concentration can be used as an indicator for subsurface NAPL contamination. The investigation showed that NAPL-contaminated soil volumes give rise to anomalous low soil-gas radon concentrations in the close vicinity of the contamination. The reason for this decrease in the soil-gas radon concentration is the good solubility of radon in NAPLs, which enables the NAPLs to accumulate and ‘trap’ part of the radon available in the soil pores. 6 Recommendations and Outlook Further research is required into contamination with rather volatile NAPLs such as BTEX. Further research is also needed to examine whether it is possible to not only localize a NAPL plume, but also to obtain some quantitative information about the subsurface NAPL contamination. The authors also believe that additional investigations should be carried out to study the ability of the method to not just localize a NAPL contamination, but also to monitor on-site, clean-up measures.
K. Freyer - One of the best experts on this subject based on the ideXlab platform.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken.
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Using the soil gas radon as an indicator for ground contamination by non-aqueous phase-liquids
Journal of Soils and Sediments, 2001Co-Authors: Michael Schubert, K. Freyer, Hans-christian Treutler, Holger WeißAbstract:1 The Problem One of the major problems facing risk assessment at polluted industrial sites and military bases is subsurface contamination by non-aqueous phase-liquids (NAPLs), since tracing the extent of a NAPL plume using conventional methods (drive point profiling) is usually associated with difficulties. In an effort to trace subsurface contamination as precisely as possible, monitoring points are placed in the area that might be affected by contaminants, and groundwater and soil samples are taken to the laboratory for analysis. However, the final number of monitoring points is hardly ever sufficient for distinctive contamination mapping, and this may ultimately result in an unsuitable Remediation Action being taken. 2 Objectives To obtain a more detailed image of a subsurface NAPL plume and, hence, to facilitate Remediation measures that are best suited for the site in question, a denser network of monitoring points is desirable. The aim of the investigation described in this paper was therefore to develop a new detection method for subsurface NAPL contamination, which is based on an easily accessible indicator for NAPLs rather than on the analysis of soil and groundwater samples taken at the site. Based on the good solubility of radon in NAPLs, the idea was put forward that subsurface NAPL contamination should have an influence on the natural radon concentration of the soil gas. Provided this effect is significant, it would be possible to carry out a straightforward radon survey on an appropriate sampling grid covering the suspected site and thus enabling the NAPL contamination to be detected by the localization of anomalous low radon concentrations in the soil. The overall aim of the investigation was to assess the general suitability of the soil-gas radon concentration as an indirect tracer for NAPL contamination in the ground. 3 Methods The partitioning coefficient K_NAPL/air is one of the most influential parameters governing the decrease of the radon concentration in the soil gas in the presence of a subsurface NAPL contamination. Since NAPL mixtures such as gasoline, diesel fuel and paraffin are among the most important NAPLs regarding Remediation activities, laboratory experiments were performed to determine the radon-partitioning coefficient for these three NAPL mixtures. Field experiments were carried out as well. The aim of the field experiments was to test the use of the soil-gas radon concentration as a tracer for NAPL contamination on-site. For the field experiments, each site was covered with a suitable grid of soil gas sampling points. Finally, the lateral radon distribution pattern achieved on each of the sites was compared to the respective findings of the earlier research performed by conventional means. 4 Results and Discussion The results of the laboratory experiments clearly show a very strong affinity of radon to the NAPL mixtures examined. The partitioning coefficients achieved correspond to those published for pure NAPLs (Clever 1979) and are thus in the expected range. The results of the field experiments showed that the minimum radon concentrations detected match the respective NAPL plumes traced previously. 5 Conclusions Both the results of the lab experiments and the on-site findings demonstrate that the soil-gas radon concentration can be used as an indicator for subsurface NAPL contamination. The investigation showed that NAPL-contaminated soil volumes give rise to anomalous low soil-gas radon concentrations in the close vicinity of the contamination. The reason for this decrease in the soil-gas radon concentration is the good solubility of radon in NAPLs, which enables the NAPLs to accumulate and ‘trap’ part of the radon available in the soil pores. 6 Recommendations and Outlook Further research is required into contamination with rather volatile NAPLs such as BTEX. Further research is also needed to examine whether it is possible to not only localize a NAPL plume, but also to obtain some quantitative information about the subsurface NAPL contamination. The authors also believe that additional investigations should be carried out to study the ability of the method to not just localize a NAPL contamination, but also to monitor on-site, clean-up measures.