The Experts below are selected from a list of 145449 Experts worldwide ranked by ideXlab platform
Ernest K. Yanful - One of the best experts on this subject based on the ideXlab platform.
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Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled Soil Cover
Applied Geochemistry, 2011Co-Authors: Qing Song, Ernest K. YanfulAbstract:An ideal engineered Soil Cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O2 ingress into an underlying waste rock pile. However, the barrier layer in the Soil Cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O2 transport in the Soil Cover and decrease performance in the long run. The present study employed a 10-cmwide sand-filled channel installed in a Soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the Cover. The Soil Cover had a slope of 20%. Oxygen transport through the Soil Cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without Soil Cover). Moreover, gaseous O2 transport in the Soil Cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the Soil Cover with channel had a lower oxidation rate than the waste rock without Cover because of reduced O2 ingress and water flushing in the Soil Cover with channel, which meant a partial Soil Cover might still be effective to some extent in reducing ARD generation. Gaseous O2 ingress into the Covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy dispersive X-ray analysis indicated that secondary minerals formed as a result of the oxidation of the waste rock included gypsum and goethite in the Covered waste rock and schwertmannite and other Fe oxides in the unCovered waste rock. The findings of the study provided insight into the effect of channel flow on O2 transport and oxidation of the Covered waste rock, which may help to improve Soil Cover design and construction to minimise the generation of preferential flow in the barrier layer.
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Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer Soil Cover.
Journal of Contaminant Hydrology, 2010Co-Authors: Qing Song, Ernest K. YanfulAbstract:Abstract Engineered Soil Covers provide an option to mitigate acid rock drainage through reduced water flow and gaseous oxygen influx to underlying mine waste. Channels such as fissures, cracks or fractures developed in the barrier may influence the long-term performance of the Soil Cover. However, limited published information is available on the extent to which Soil Cover performance is impacted by these fissures and cracks. This study was conducted to investigate the effect of channelling in a barrier layer on water flow and oxygen transport in a Soil Cover. Two inclined (a slope of 20%) multilayer Soil Covers were examined under laboratory conditions. One Cover had a 10-cm wide sand-filled channel in a compacted barrier layer (silty clay) at the upslope section, while the other Cover was a normal one without the channel pathway. The Soil Covers were installed in plastic boxes measuring 120 cm × 120 cm × 25 cm (width × height × thickness). The sand-filled channel was designed to represent the aggregate of fissures and cracks that may be present in the compacted barrier. The Soil Covers were subjected to controlled drying and wetting periods selected to simulate field situation at the Whistle mine site near Capreol, Ontario, Canada. The measured results indicated that interflow decreased from 72.8% of the total precipitation in the Soil Cover without channel flow to 35.3% in the Cover with channel flow, and percolation increased from zero in the normal Soil Cover to 43.0% of the total precipitation in the Cover with channel flow. Gaseous oxygen transfer into the waste rock below the Cover Soils was 1091 times greater in the Cover with channel than in the Soil Cover without channel. The channel pathway present in the barrier layer acted as a major passage for water movement and gaseous oxygen diffusion into the waste rock layer, thus decreasing the performance of the Soil Cover. The spacing of the channel with respect to the length of the test box is similar to those found in other published fracture networks. The distribution and partitioning of the water balance components would be expected to be similar to other situations with the same Cover slope. This, of course, would depend on rainfall intensity.
Qing Song - One of the best experts on this subject based on the ideXlab platform.
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Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled Soil Cover
Applied Geochemistry, 2011Co-Authors: Qing Song, Ernest K. YanfulAbstract:An ideal engineered Soil Cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O2 ingress into an underlying waste rock pile. However, the barrier layer in the Soil Cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O2 transport in the Soil Cover and decrease performance in the long run. The present study employed a 10-cmwide sand-filled channel installed in a Soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the Cover. The Soil Cover had a slope of 20%. Oxygen transport through the Soil Cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without Soil Cover). Moreover, gaseous O2 transport in the Soil Cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the Soil Cover with channel had a lower oxidation rate than the waste rock without Cover because of reduced O2 ingress and water flushing in the Soil Cover with channel, which meant a partial Soil Cover might still be effective to some extent in reducing ARD generation. Gaseous O2 ingress into the Covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy dispersive X-ray analysis indicated that secondary minerals formed as a result of the oxidation of the waste rock included gypsum and goethite in the Covered waste rock and schwertmannite and other Fe oxides in the unCovered waste rock. The findings of the study provided insight into the effect of channel flow on O2 transport and oxidation of the Covered waste rock, which may help to improve Soil Cover design and construction to minimise the generation of preferential flow in the barrier layer.
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Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer Soil Cover.
Journal of Contaminant Hydrology, 2010Co-Authors: Qing Song, Ernest K. YanfulAbstract:Abstract Engineered Soil Covers provide an option to mitigate acid rock drainage through reduced water flow and gaseous oxygen influx to underlying mine waste. Channels such as fissures, cracks or fractures developed in the barrier may influence the long-term performance of the Soil Cover. However, limited published information is available on the extent to which Soil Cover performance is impacted by these fissures and cracks. This study was conducted to investigate the effect of channelling in a barrier layer on water flow and oxygen transport in a Soil Cover. Two inclined (a slope of 20%) multilayer Soil Covers were examined under laboratory conditions. One Cover had a 10-cm wide sand-filled channel in a compacted barrier layer (silty clay) at the upslope section, while the other Cover was a normal one without the channel pathway. The Soil Covers were installed in plastic boxes measuring 120 cm × 120 cm × 25 cm (width × height × thickness). The sand-filled channel was designed to represent the aggregate of fissures and cracks that may be present in the compacted barrier. The Soil Covers were subjected to controlled drying and wetting periods selected to simulate field situation at the Whistle mine site near Capreol, Ontario, Canada. The measured results indicated that interflow decreased from 72.8% of the total precipitation in the Soil Cover without channel flow to 35.3% in the Cover with channel flow, and percolation increased from zero in the normal Soil Cover to 43.0% of the total precipitation in the Cover with channel flow. Gaseous oxygen transfer into the waste rock below the Cover Soils was 1091 times greater in the Cover with channel than in the Soil Cover without channel. The channel pathway present in the barrier layer acted as a major passage for water movement and gaseous oxygen diffusion into the waste rock layer, thus decreasing the performance of the Soil Cover. The spacing of the channel with respect to the length of the test box is similar to those found in other published fracture networks. The distribution and partitioning of the water balance components would be expected to be similar to other situations with the same Cover slope. This, of course, would depend on rainfall intensity.
T. Katsumi - One of the best experts on this subject based on the ideXlab platform.
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seashore msw landfill using drainage layer and thick Soil Cover leachate containment and post closure land use
The International Congress on Environmental Geotechnics, 2018Co-Authors: N. Maeda, J. Tsukahara, Kazuto Endo, M. Kamon, T. KatsumiAbstract:Environmental conservation and post-closure land use are important considerations in seashore MSW landfills. A system consisting of a drainage layer and thick Soil Cover installed over a waste layer is considered an effective measure for the containment of waste leachate and post-closure land use. In this study, the effectiveness of such a system of drainage layer and thick Soil Cover was evaluated via laboratory experiments and numeral analysis. Laboratory experimental results indicated that water discharged through the drainage layer achieves satisfactory quality, as waste leachate can be properly contained in the waste layer owing to the function of the drainage layer. Numerical analysis also revealed the effectiveness of the drainage layer in containing waste leachate. The proposed system is expected to perform satisfactorily in terms of leachate containment and post-closure land use.
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Seashore MSW Landfill Using Drainage Layer and Thick Soil Cover—Leachate Containment and Post-closure Land Use
Environmental Science and Engineering, 2018Co-Authors: N. Maeda, J. Tsukahara, Kazuto Endo, M. Kamon, T. KatsumiAbstract:Environmental conservation and post-closure land use are important considerations in seashore MSW landfills. A system consisting of a drainage layer and thick Soil Cover installed over a waste layer is considered an effective measure for the containment of waste leachate and post-closure land use. In this study, the effectiveness of such a system of drainage layer and thick Soil Cover was evaluated via laboratory experiments and numeral analysis. Laboratory experimental results indicated that water discharged through the drainage layer achieves satisfactory quality, as waste leachate can be properly contained in the waste layer owing to the function of the drainage layer. Numerical analysis also revealed the effectiveness of the drainage layer in containing waste leachate. The proposed system is expected to perform satisfactorily in terms of leachate containment and post-closure land use.
Yongfeng Nie - One of the best experts on this subject based on the ideXlab platform.
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Impact assessment of intermediate Soil Cover on landfill stabilization by characterizing landfilled municipal solid waste
Journal of environmental management, 2013Co-Authors: Dongbei Yue, Jianguo Liu, Xiaochong Shi, Jingting Guo, Haomei Miao, Yongfeng NieAbstract:Abstract Waste samples at different depths of a Covered municipal solid waste (MSW) landfill in Beijing, China, were excavated and characterized to investigate the impact of intermediate Soil Cover on waste stabilization. A comparatively high amount of unstable organic matter with 83.3 g kg−1 dry weight (dw) total organic carbon was detected in the 6-year-old MSW, where toxic inorganic elements containing As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn of 10.1, 0.98, 85.49, 259.7, 530.4, 30.5, 84.0, and 981.7 mg kg−1 dw, respectively, largely accumulated because of the barrier effect of intermediate Soil Cover. This accumulation resulted in decreased microbial activities. The intermediate Soil Cover also caused significant reduction in moisture in MSW under the Soil layer, which was as low as 25.9%, and led to inefficient biodegradation of 8- and 10-year-old MSW. Therefore, intermediate Soil Cover with low permeability seems to act as a barrier that divides a landfill into two landfill cells with different degradation processes by restraining water flow and hazardous matter.
N. Maeda - One of the best experts on this subject based on the ideXlab platform.
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seashore msw landfill using drainage layer and thick Soil Cover leachate containment and post closure land use
The International Congress on Environmental Geotechnics, 2018Co-Authors: N. Maeda, J. Tsukahara, Kazuto Endo, M. Kamon, T. KatsumiAbstract:Environmental conservation and post-closure land use are important considerations in seashore MSW landfills. A system consisting of a drainage layer and thick Soil Cover installed over a waste layer is considered an effective measure for the containment of waste leachate and post-closure land use. In this study, the effectiveness of such a system of drainage layer and thick Soil Cover was evaluated via laboratory experiments and numeral analysis. Laboratory experimental results indicated that water discharged through the drainage layer achieves satisfactory quality, as waste leachate can be properly contained in the waste layer owing to the function of the drainage layer. Numerical analysis also revealed the effectiveness of the drainage layer in containing waste leachate. The proposed system is expected to perform satisfactorily in terms of leachate containment and post-closure land use.
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Seashore MSW Landfill Using Drainage Layer and Thick Soil Cover—Leachate Containment and Post-closure Land Use
Environmental Science and Engineering, 2018Co-Authors: N. Maeda, J. Tsukahara, Kazuto Endo, M. Kamon, T. KatsumiAbstract:Environmental conservation and post-closure land use are important considerations in seashore MSW landfills. A system consisting of a drainage layer and thick Soil Cover installed over a waste layer is considered an effective measure for the containment of waste leachate and post-closure land use. In this study, the effectiveness of such a system of drainage layer and thick Soil Cover was evaluated via laboratory experiments and numeral analysis. Laboratory experimental results indicated that water discharged through the drainage layer achieves satisfactory quality, as waste leachate can be properly contained in the waste layer owing to the function of the drainage layer. Numerical analysis also revealed the effectiveness of the drainage layer in containing waste leachate. The proposed system is expected to perform satisfactorily in terms of leachate containment and post-closure land use.
