非水相液体（NAPL）截留条件对空气注射修复效率的影响。

Effect of NAPL entrapment conditions on air sparging remediation efficiency.

作者信息

Waduge W A P, Soga K, Kawabata J

机构信息

Engineering Department, University of Cambridge, Cambridge, UK.

出版信息

J Hazard Mater. 2004 Jul 5;110(1-3):173-83. doi: 10.1016/j.jhazmat.2004.02.050.

DOI:10.1016/j.jhazmat.2004.02.050

PMID:15177738

Abstract

The effect of soil heterogeneity and the entrapment condition of NAPL source on the mass removal efficiency of air sparging coupled with soil vapour extraction (AS/SVE) was investigated using an intermediate scale two-dimensional laboratory soil tank. Four different NAPL entrapments were created by varying the height of the water table in heterogeneous soil models. Different mass removal efficiencies were achieved for different NAPL entrapment conditions, which were governed by soil heterogeneity and water table height before and during AS/SVE operation. Remobilization and redistribution of toluene and water improved the mass removal. Overall results suggested that it was difficult to achieve the complete remediation of NAPL source due to complex entrapment in heterogeneous soil system. In order to assess the potential contamination in the post-remediation stage, gas and dissolved concentrations of toluene were measured after the AS/SVE operation. The results showed that gas concentration close to remaining NAPL source zone increased rapidly and reached to steady state values, which were much smaller than the vapour pressure, whereas the aqueous phase concentrations increased continuously toward the solubility limit.

摘要

利用中尺度二维实验室土槽，研究了土壤非均质性和非水相液体（NAPL）源的截留条件对空气注入与土壤气相抽提联合技术（AS/SVE）去除污染物质量效率的影响。通过改变非均质土壤模型中地下水位的高度，创建了四种不同的NAPL截留情况。在不同的NAPL截留条件下，实现了不同的污染物去除效率，这在AS/SVE操作之前和期间受土壤非均质性和地下水位高度的控制。甲苯和水的再迁移和再分布提高了污染物去除量。总体结果表明，由于非均质土壤系统中复杂的截留情况，难以实现对NAPL源的完全修复。为了评估修复后阶段的潜在污染，在AS/SVE操作后测量了甲苯的气相和溶解浓度。结果表明，靠近残留NAPL源区的气相浓度迅速增加并达到稳态值，该值远小于蒸气压，而水相浓度则持续增加至溶解度极限。