Treatability of volatile chlorinated hydrocarbon-contaminated soils of different textures along a vertical profile by mechanical soil aeration: A laboratory test |
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Authors: | Yan M Yi Shi Deyi Hou Xi Zhang Jiaqi Chen Zhifen Wang Zhu Xu Fasheng Li Xiaoming Du |
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Institution: | 1 School of Chemical and Environmental Engineering, China University of Mining &Technology, Beijing 100083, China;2 State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;3 School of Environment, Tsinghua University, Beijing 100084, China;4 BGI Engineering Consultants Ltd., Beijing 100038, China;5 School of Environment and Energy, Peking University, Shenzhen 518055, China |
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Abstract: | Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons (VCHs). Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures (silty, clayey, and sandy soils) along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform (TCM) and trichloroethylene (TCE). Mechanical soil aeration was effective for remediating VCHs (removal efficiency > 98%). The volatilization process was described by an exponential kinetic function. In the early stage of treatment (0–7 hr), rapid contaminant volatilization followed a pseudo-first order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8 hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner. |
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Keywords: | Contaminated site Texture of soil profile Particle-size fraction Volatile chlorinated hydrocarbons (VCHs) Mechanical soil aeration Treatability test |
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