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Soil air permeability plays a decisive role in the effectiveness of soil vapour extraction (SVE) for the removal of volatile organic contaminants (VOCs) from soil. The objective of this work is to study the change of the soil air permeability during continuous venting and removal of contaminant from a polluted soil. SVE pilot experiments were conducted to investigate the interaction of soil air permeability with total liquids saturation. Oppositely to previous studies, air permeability was measured by fitting pressure data measured in a 3D laboratory venting pilot to an analytical airflow solution. The experimental correlation was compared with two different correlations published previously. A difference was observed between measured and calculated air relative air permeabilities especially for low water saturation degrees. The importance of the correct estimate of relative permeability was then illustrated by comparing vacuums and streamlines calculated using measured permeability and permeability values estimated with the two correlations tested here. Results show that an inappropriate assessment of relative permeability may engender significant errors in designing an SVE system. The second part of this work reports on the influence of air permeability change on the prediction capability of an SVE mathematical model. A significant difference between simulated breakthrough curves, estimated using firstly the relationship established experimentally and secondly the two other correlations, was observed. These results lead us to say that inadequate characterization of the air permeability change may generate significant errors in removal rate and closure time estimates. 相似文献
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Raji Otmane Ouabid Muhammad Bodinier Jean-Louis El Messbahi Hicham Malainine Cheikh Elwali Tabbakh Zineb 《Natural Resources Research》2021,30(5):3219-3239
Natural Resources Research - Potassium (K)-rich igneous rocks include a variety of silica-undersaturated and alkaline rocks, which distinguished by their elevated K2O contents. These rocks have... 相似文献
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This study looks at the influence of surface covers on the performance of a single pumping well system. Pilot tests were conducted on a sandy soil to determine the influence of surface confinement based upon both induced vacuum and pore gas velocity design criteria. The results demonstrate how covering the surface can significantly alter the associated air flow patterns and velocity distribution. Comparison of streamline iso‐contours obtained in covered scenarios reveals that the surface seal tended to prevent air from entering the subsurface near the extraction well and force air to be drawn from a greater distance. Calculated and measured pressure differentials, for open and semi‐confined scenarios, clearly show that adding a clay layer as a surface cover increased the vacuum induced within the soil. Pore gas velocity analysis showed that when the cover clay layer was used, the zone of capture of the soil vapor extraction system increased. The radius of influence of soil vapor extraction (SVE) systems, based on the attainment of a critical vacuum or pore gas velocity, can then be increased by including a surface seal in the design of such systems. The focus of this study is limited to air flow patterns contrasted between covered and uncovered conditions and not on the nuances of a full scale remediation implementation. 相似文献
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