An analytical solution to equations describing rate-limited soil vapor extraction of contaminants in the vadose zone
An analytical solution to equations describing rate-limited soil vapor extraction of contaminants in the vadose zone
复制标题
描述包气带污染物限速土壤蒸汽提取的方程的解析解
DOI：
10.1029/94wr01775
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发表时间：
1994
影响因子：
5.4
通讯作者：
M. Oxley
中科院分区：
文献类型：
--
作者：
M. Goltz;M. Oxley
土壤蒸气提取(SVE)是一种常用的从包气带中去除挥发性有机化合物的技术。最近的研究表明，这些化合物的限速吸附和解吸可以对SVE实现的浓度降低产生深远的影响。在这篇笔记中，布鲁塞尔(1991)提出的描述包气带中吸附有机化合物的限速传输的一维方程被修改为在理想位置的SVE修复模型并进行了解析求解。本文提出的分析模型描述了有机污染物在包气带内收敛的径向流场中的传输，吸附速率极限用一阶速率表达式描述。模型方程在拉普拉斯域中求解，并进行数值反演，以模拟抽油井的污染物浓度。文中还给出了包气带内污染物总质量的拉普拉斯域解。结果表明，在一定条件下，限速吸附对包气带中SVE的修复有显著影响。本说明中提出的解决方案可能有助于验证正在开发的数值代码，这些代码正在开发以模拟速率限制吸附条件下包气带中的有机传输。
Soil vapor extraction (SVE) is a technique that is commonly used to remove volatile organic compounds from the vadose zone. Recent research has demonstrated that rate-limited sorption and desorption of these compounds can have a profound impact on the concentration reductions achievable by SVE. In this note, one-dimensional equations presented by Brusseau (1991), which describe rate-limited transport of sorbing organic compounds in the vadose zone, are modified to model a SVE remediation at an idealized site and analytically solved. The analytical model presented herein describes transport of a sorbing organic contaminant in a converging radial flow field in the vadose zone, with sorption rate limitations described by first-order rate expressions. The model equations are solved in the Laplace domain and numerically inverted to simulate contaminant concentrations at an extraction well. A Laplace domain solution for the total contaminant mass remaining in the vadose zone is also derived. It is shown that under certain conditions, rate-limited sorption can have a significant impact upon SVE remediation in the vadose zone. The solutions presented in this note may be useful in verifying numerical codes which are being developed to model organic transport in the vadose zone under conditions of rate-limited sorption.