Institut UTINAM, Université de Bourgogne Franche-Comté, 16 Route de Gray, 25000 Besançon, France.
SERPOL, 2 Chemin du Génie, 69633 Vénissieux, France.
Sci Total Environ. 2018 Jan 15;612:1149-1158. doi: 10.1016/j.scitotenv.2017.08.309. Epub 2017 Sep 8.
Immiscible mobilization and foam flushing were assessed as low surfactant consuming technologies, for the enhanced recovery of dense non-aqueous phase liquid (DNAPL) residual at a site contaminated by heavy chlorinated compounds. Preliminary experiments in well-controlled conditions demonstrated the phenomena involved in these remediation technologies and their limitations. Furthermore, we characterized the technologies according to by their surfactant consumption (per kg of DNAPL recovered) and the final DNAPL saturation reached. Surfactant foam flushing (SFF) produced lower DNAPL saturation than immiscible mobilization, thanks to its higher viscosity. However, its efficiency is strongly correlated to the pressure gradient (▽P) used during injection, and that is limited by risks of soil fracturing. The two technologies were tested in field cells (10m×10m×10m) delimited by cement/bentonite walls anchored in the clayey substratum. The deepest soil layer was the most contaminated. It was composed of silt-sandy soil and had an average hydraulic conductivity of 10ms. Field results show that we should now model flushing fluid propagation to design efficient set-ups for recovering the displaced DNAPL.
不可混相驱替和泡沫冲洗被评估为低表面活性剂消耗技术，用于强化回收受重氯化物污染的致密非水相液体（DNAPL）残留。在良好控制条件下的初步实验证明了这些修复技术中涉及的现象及其局限性。此外，我们根据其表面活性剂消耗（每回收公斤 DNAPL）和最终达到的 DNAPL 饱和度来对这些技术进行了特征描述。由于其较高的粘度，表面活性剂泡沫冲洗（SFF）产生的 DNAPL 饱和度低于不可混相驱替。然而，其效率与注入过程中使用的压力梯度（▽P）强烈相关，而压力梯度受到土壤破裂风险的限制。这两种技术在由水泥/膨润土墙围起来的田间单元（10m×10m×10m）中进行了测试，这些墙锚固在粘土地层中。最深的土壤层受到的污染最严重。它由粉砂土壤组成，平均水力传导率为 10ms。现场结果表明，我们现在应该对冲洗液的传播进行建模，以设计有效的方案来回收被驱替的 DNAPL。
