Soil vapor extraction (SVE), the most common, efficient and economical means of remediation, is an in-situ remediation technique for removing volatile pollutants from unsaturated soil. The paper brie fly introduced th...Soil vapor extraction (SVE), the most common, efficient and economical means of remediation, is an in-situ remediation technique for removing volatile pollutants from unsaturated soil. The paper brie fly introduced the technological rationale and characteristics, summarized the theories and application research for SVE at home and abroad, and made the expectations and suggestions for the research on SVE. The international scholars have systematically researched the influence factors, remediation mechanism and numerical simulation of SVE. At present, SVE has been mostly integrated with other techniques to form enhanced SVE techniques, such as thermally enhanced SVE and AS-SVE (Air sparging- SVE), to be used for the field remediation widely. Compared with foreign countries, researches of Chinese scholars mainly focus on the laboratory research, especially on the influence factors, but rarely study the SVE model and the mass transfer mechanism of pollutant in SVE process. The SVE pilot studies are rare in China, and the field application has not been reported. In view of this situation, Chinese scholars in the future research can focus on the following aspects: (1) strengthening the research and systematized summary of SVE technical parameters and related knowledge;(2) strengthening the research on the mechanism and model of gas-phase mass transfer of pollutants in soil during SVE process;(3) strengthening the research on the enhanced SVE techniques and its application to actual site remediation.展开更多
The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor extraction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization ...The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor extraction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization of three single-component NAPLs in a sandy soil, constant initial lumped mass transfer coefficient (λgN,0) canbe obtained if the relative saturation (ξ) between NAPL phase and gas phase is higher than a critical value (ξc), andthe lumped mass transfer coefficient decreases with ξ when ξ＜ξc. It is also shown that the lumped mass transfercoefficient can be increased by blending porous micro-particles into the sandy soil because of the increasing of theinterfacial area.展开更多
针对烃类污染土壤的修复,本文采用热强化土壤气相抽提(soil vapor extraction,SVE)技术,分别研究了通气、土壤物性和温度等参数对污染土壤中挥发性有机物脱除效率的影响规律。结果表明:延长通气时间,出口浓度(LEL%)逐步降低,最后进入拖...针对烃类污染土壤的修复,本文采用热强化土壤气相抽提(soil vapor extraction,SVE)技术,分别研究了通气、土壤物性和温度等参数对污染土壤中挥发性有机物脱除效率的影响规律。结果表明:延长通气时间,出口浓度(LEL%)逐步降低,最后进入拖尾期,连续通气比间断通气更利于土壤中烃类污染物的去除,适当加大通气流速可提高去除效率。适当增大土壤粒径有利于有机物组分的迁移,且沸点低的碳氢(hydrogen and carbureted,HC)组分更易去除。床层加热方式较气体加热方式去除效率高。综合分析,通气速率和温度是影响去除效率的最主要因素,80 m L/min的通气流速、连续通气、80℃的床层温度为最优参数,吹脱时间为250 min时出口浓度(LEL%)达到6%。展开更多
Based on the theory of fluid dynamics in porous media, a numerical model of gas flow in unsaturated zone is developed with the consideration of gas density change due to variation of air pressure. This model is charac...Based on the theory of fluid dynamics in porous media, a numerical model of gas flow in unsaturated zone is developed with the consideration of gas density change due to variation of air pressure. This model is characterized of its wider range of availability. The accuracy of this numerical model is analyzed through comparison with modeling results by previous model with presumption of little pressure variation and the validity of this numerical model is shown. Thus it provides basis for the designing and management of landfill gas control system or soil vapor extraction system in soil pollution control.展开更多
为研究气相抽提技术(SVE)现场去污效果及影响因素,在北京市某化工厂搬迁遗留场地,以苯系物为目标污染物,应用气相抽提法进行场地污染修复现场小试,考察了气相抽提真空度、气体抽排流量、空气渗透率及温度变化等的影响。试验结果表明,抽...为研究气相抽提技术(SVE)现场去污效果及影响因素,在北京市某化工厂搬迁遗留场地,以苯系物为目标污染物,应用气相抽提法进行场地污染修复现场小试,考察了气相抽提真空度、气体抽排流量、空气渗透率及温度变化等的影响。试验结果表明,抽提真空度存在最优值(试验场地在30 k Pa左右),在该值附近,抽取的气体流量最大(流量为13.5 m3/h);抽出气体的污染物浓度及去污速率随流量增大而提高,在不考虑污染物由土壤中迁移过程的限制时,去污速率基本正比于抽气流量;土壤的透气性越强,气相抽提的影响半径越大,抽气流量以及去除污染物的速率也越高;抽出气体的污染物浓度及去除速率总体随温度的升高而增大。展开更多
基金supported by the Fundamental Research Funds from Chinese Academy of Geological Sciences(YYWF201516)National Natural Science Foundation of China(41402230)
文摘Soil vapor extraction (SVE), the most common, efficient and economical means of remediation, is an in-situ remediation technique for removing volatile pollutants from unsaturated soil. The paper brie fly introduced the technological rationale and characteristics, summarized the theories and application research for SVE at home and abroad, and made the expectations and suggestions for the research on SVE. The international scholars have systematically researched the influence factors, remediation mechanism and numerical simulation of SVE. At present, SVE has been mostly integrated with other techniques to form enhanced SVE techniques, such as thermally enhanced SVE and AS-SVE (Air sparging- SVE), to be used for the field remediation widely. Compared with foreign countries, researches of Chinese scholars mainly focus on the laboratory research, especially on the influence factors, but rarely study the SVE model and the mass transfer mechanism of pollutant in SVE process. The SVE pilot studies are rare in China, and the field application has not been reported. In view of this situation, Chinese scholars in the future research can focus on the following aspects: (1) strengthening the research and systematized summary of SVE technical parameters and related knowledge;(2) strengthening the research on the mechanism and model of gas-phase mass transfer of pollutants in soil during SVE process;(3) strengthening the research on the enhanced SVE techniques and its application to actual site remediation.
基金Supported by the National Natural Science Foundation of China (No. 20276048).
文摘The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor extraction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization of three single-component NAPLs in a sandy soil, constant initial lumped mass transfer coefficient (λgN,0) canbe obtained if the relative saturation (ξ) between NAPL phase and gas phase is higher than a critical value (ξc), andthe lumped mass transfer coefficient decreases with ξ when ξ＜ξc. It is also shown that the lumped mass transfercoefficient can be increased by blending porous micro-particles into the sandy soil because of the increasing of theinterfacial area.
文摘针对烃类污染土壤的修复,本文采用热强化土壤气相抽提(soil vapor extraction,SVE)技术,分别研究了通气、土壤物性和温度等参数对污染土壤中挥发性有机物脱除效率的影响规律。结果表明:延长通气时间,出口浓度(LEL%)逐步降低,最后进入拖尾期,连续通气比间断通气更利于土壤中烃类污染物的去除,适当加大通气流速可提高去除效率。适当增大土壤粒径有利于有机物组分的迁移,且沸点低的碳氢(hydrogen and carbureted,HC)组分更易去除。床层加热方式较气体加热方式去除效率高。综合分析,通气速率和温度是影响去除效率的最主要因素,80 m L/min的通气流速、连续通气、80℃的床层温度为最优参数,吹脱时间为250 min时出口浓度(LEL%)达到6%。
基金TheResearchFundfortheDoctoralProgramofHighEducation P .R .China(No 980 0 2 712 )
文摘Based on the theory of fluid dynamics in porous media, a numerical model of gas flow in unsaturated zone is developed with the consideration of gas density change due to variation of air pressure. This model is characterized of its wider range of availability. The accuracy of this numerical model is analyzed through comparison with modeling results by previous model with presumption of little pressure variation and the validity of this numerical model is shown. Thus it provides basis for the designing and management of landfill gas control system or soil vapor extraction system in soil pollution control.
文摘为研究气相抽提技术(SVE)现场去污效果及影响因素,在北京市某化工厂搬迁遗留场地,以苯系物为目标污染物,应用气相抽提法进行场地污染修复现场小试,考察了气相抽提真空度、气体抽排流量、空气渗透率及温度变化等的影响。试验结果表明,抽提真空度存在最优值(试验场地在30 k Pa左右),在该值附近,抽取的气体流量最大(流量为13.5 m3/h);抽出气体的污染物浓度及去污速率随流量增大而提高,在不考虑污染物由土壤中迁移过程的限制时,去污速率基本正比于抽气流量;土壤的透气性越强,气相抽提的影响半径越大,抽气流量以及去除污染物的速率也越高;抽出气体的污染物浓度及去除速率总体随温度的升高而增大。
