Hydrogeology Journal

, Volume 23, Issue 8, pp 1703–1718 | Cite as

Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

Paper

Abstract

Understanding the migration of dense non-aqueous phase liquids (DNAPLs) in complex subsurface systems is important for evaluating contamination source zones and designing remediation schemes after spill events. Six sandbox experiments were performed to explore the individual effect of flow velocity, and the combined effect of flow velocity and layered lenses on a DNAPL (PCE) migration in porous media. DNAPL saturation was measured using a light transmission system, and saturation distribution was quantified by spatial moments. The experimental results show that large flow velocity significantly promotes lateral and vertical migration of the low-viscosity DNAPL, while when layered lenses exist, the infiltration rate decreases and horizontal spread increases. Migration processes were numerically simulated, and the modelling results tested against experimental results. Furthermore, migration of DNAPLs with different viscosities was simulated to explore the combined effects of flow velocity and geological heterogeneity. Simulation results show that enhanced heterogeneity makes low-viscosity DNAPLs migrate along preferential pathways, resulting in irregular DNAPL morphology. Layered lenses combined with heterogeneity complicate the effect of flow velocity on the migration of low-viscosity DNAPLs by changing percolation paths. Results also demonstrate that flow velocity exhibits relatively little influence on the migration of medium/high-viscosity DNAPLs, which is predominantly controlled by viscosity and heterogeneity. Enhanced heterogeneity has a larger effect on migration behavior. Findings indicate that the migration paths and position of the source zone could change significantly, due to the combined effect of groundwater flow velocity and geological heterogeneity; thus, comprehensive hydrogeological investigation is needed to characterize the source zone.

Keywords

Multiphase flow Groundwater hydraulics Heterogeneity Laboratory experiments Numerical modelling 

Influence de la vitesse d’écoulement et de l’hétérogénéité spatiale sur la migration de phase liquide non aqueuse dense (DNAPL) en milieu poreux: aperçus des expériences en laboratoire et de modélisation numérique

Résumé

Comprendre la migration des phases liquides denses non-aqueuse (DNAPL) dans les systèmes souterrains complexes est important pour évaluer les zones de la source de contamination et la conception de systèmes d’assainissement après les incidents de déversements. Six expériences dans des bacs à sables ont été réalisées pour étudier l’effet individuel de la vitesse d’écoulement et l’effet combiné de la vitesse d’écoulement et des lentilles sur la migration du DNAPL (PCE) dans un milieu poreux. La saturation en DNAPL est mesurée en utilisant un système de transmission de la lumière, et la distribution de saturation a été quantifiée par les moments spatiaux. Les résultats expérimentaux montrent que la grande vitesse d’écoulement favorise considérablement la migration latérale et verticale du DNAPL de faible viscosité, tandis que lorsque des lentilles en couches existent, le taux d’infiltration diminue et la propagation horizontale augmente. Les processus de migration ont été simulés numériquement et les résultats de la modélisation ont été comparés aux résultats expérimentaux. En outre, la migration des DNAPLs avec différentes viscosités a été simulée pour explorer les effets combinés de la vitesse d’écoulement et de l’hétérogénéité géologique. Les résultats de simulation montrent qu’une hétérogénéité accrue favorise la migration de DNAPL de faible viscosité le long de cheminements préférentiels, entraînant une morphologie irrégulière du DNAPL. Des lentilles en couches combinées avec une hétérogénéité compliquent l’effet de la vitesse d’écoulement sur la migration des DNAPLs de faible viscosité en modifiant les chemins de percolation. Les résultats démontrent également que la vitesse d’écoulement provoque une petite influence sur la migration des DNAPLs de viscosité moyenne à élevée, qui est principalement contrôlée par la viscosité et l’hétérogénéité. L’hétérogénéité accrue a un effet plus important sur le comportement de la migration. Les résultats indiquent que les chemins de migration et la position de la zone source pourraient changer de manière significative, en raison de l’effet combiné de la vitesse d’écoulement d’eaux souterraines et de l’hétérogénéité géologique ; ainsi une étude hydrogéologique globale est nécessaire pour caractériser la zone source.

Influencia de la velocidad del flujo y de la heterogeneidad espacial en la migración de un DNAPL en medios porosos: conocimientos a partir de experimentos de laboratorio y de un modelado numérico

Resumen

La comprensión de la migración de líquidos densos en fase no acuosa (DNAPLs) en sistemas subterráneos complejos es importante para evaluar las zonas de las fuentes de la contaminación y para diseñar planes de remediación después de los eventos de derrames. Se llevaron a cabo seis experimentos en recintos de seguridad para explorar el efecto individual de la velocidad de flujo, y el efecto combinado de la velocidad de flujo y lentes estratificadas en la migración del DNAPL (PCE) en el medio poroso. La saturación del DNAPL se midió utilizando un sistema de transmisión de luz, y la distribución de saturación se cuantificó por momentos espaciales. Los resultados experimentales muestran que una gran velocidad del flujo favorece significativamente la migración lateral y vertical del DNAPL de baja viscosidad, mientras que cuando existen lentes estratificadas, disminuye la tasa de infiltración y aumenta la propagación horizontal. Se simularon numéricamente los procesos de migración, y los resultados de los modelos se testearon contra resultados experimentales. Además, se simuló la migración de DNAPLs con diferentes viscosidades para explorar los efectos combinados de la velocidad de flujo y la heterogeneidad geológica. Los resultados de la simulación muestran que el aumento en la heterogeneidad hace que los DNAPLs de baja viscosidad migren a lo largo de las vías preferenciales, lo que resulta en una morfología irregular del DNAPL. Las lentes estratificadas combinadas con la heterogeneidad complican el efecto de la velocidad de flujo de la migración de los DNAPLs de baja viscosidad cambiando las trayectorias de la percolación. Los resultados también demuestran que la velocidad de flujo exhibe una influencia relativamente pequeña en la migración de los DNAPLs de media / alta viscosidad, que son controlados predominantemente por la viscosidad y la heterogeneidad. Una acentuada heterogeneidad tiene un mayor efecto sobre el comportamiento de la migración. Los hallazgos indican que las trayectorias de la migración y la posición de la zona de la fuente podrían cambiar significativamente, debido al efecto combinado de la velocidad del flujo de agua subterránea y la heterogeneidad geológica; por lo tanto, se necesita una investigación hidrogeológica integral para caracterizar la zona de la fuente.

流速和空间非均质性对孔隙介质中重非水相流体运移的影响:室内实验和数值模拟得到的认识

摘要

了解复杂的地下系统中重非水相流体的运移对于出现污染事件时评估污染源区和设计修复方案非常重要。本文进行了6个砂箱实验以探索流速对孔隙介质中重非水相流体运移的单一影响以及流速和层状透镜体对重非水相流体运移的综合影响。采用光透射系统对重非水相流体饱和度进行的测量,通过空间矩量化了饱和分布。实验结果显示,较大的流速促进低粘度重非水相流体的侧向和垂向运移,而存在层状透晶体时,重非水相流体的垂向入渗率降低,水平扩散范围 增加。对运移过程进行了数值模拟,模拟结果验证了实验结果。此外,还模拟了不同粘性的重非水相流体运移,以探索流速和地质非均质性性的综合影响。模拟结果显示非均质性增强使低粘性重非水相流体沿优先通道运移,造成不规则的分布形态。层状透镜体结合非均质性改变了渗流通路,使流速对低粘性重非水相流体的影响更加复杂。结果还显示,流速对中/高粘性重非水相流体运移的影响相对较小,主要受控于粘性和非均质性。非均质性增强对运移行为有较大的影响。上述结果表明,由于地下水流速和地质非均质性的综合影响,运移通道和污染源区的位置变化会很大。因此,需要进行水文地质调查来描述污染源区的特征。

Influência da velocidade de fluxo e heterogeneidade especial na migração DNAPL em meios porosos: entendimento a partir de experimentos laboratoriais e modelagem numérica

Resumo

Entender a migração de compostos de fase líquida densa não aquosa (DNAPLs) em sistemas subsuperficiais complexos é importante para avaliar zonas de fontes contaminantes e projetar esquemas de remediação após eventos de derramamento. Seis experimentos de caixa de areia foram executados para explorar o efeito individual da velocidade de fluxo, e o efeito combinado da velocidade de fluxo e lentes sobrepostas na migração DNAPL (PCE) em meios porosos. A saturação por DNAPL foi medida utilizando um sistema de transmissão de luz, e a distribuição de saturação foi quantificada por momentos espaciais. Os resultados experimentais mostram que grandes velocidades de fluxo promovem migração lateral e vertical significante de DNAPL de baixa densidade, porém quando existem lentes sobrepostas, a taxa de infiltração diminui e a propagação horizontal aumenta. Processos de migração foram simulados numericamente, e os resultados dos modelos testados contra os resultados experimentais. Além do mais, as migrações de DNAPL com viscosidades diferentes foram simuladas para explorar os efeitos combinados de velocidade de fluxo e heterogeneidade geológica. Os resultados da simulação mostram que a heterogeneidade acentuada faz com que DNAPLs de baixa viscosidade migrem por caminhos preferenciais, resultando em uma morfologia DNAPL irregular. Lentes sobrepostas combinadas com heterogeneidade complicam o efeito da velocidade de fluxo na migração de DNAPLs de baixa viscosidade pela mudança nos caminhos de percolação. Os resultados também demonstram que a velocidade de fluxo exibe relativamente pouca influência na migração de DNAPLs de média e alta viscosidade, que é predominantemente controlada pela viscosidade e heterogeneidade. A heterogeneidade acentuada tem maior efeito no comportamento da migração. As descobertas indicam que os caminhos de migração e a posição da zona de fontes podem mudar significantemente pelo efeito combinado da velocidade de fluxo das águas subterrâneas e heterogeneidade geológica, assim uma investigação hidrogeológica abrangente é necessária para caracterizar as zonas de fontes

Supplementary material

10040_2015_1314_MOESM1_ESM.pdf (311 kb)
ESM 1(PDF 311 kb)

References

  1. Bob MM, Brooks MC, Mravik SC, Wood AL (2008) A modified light transmission visualization method for DNAPL saturation measurements in 2-D models. Adv Water Resour 31(5):727–742CrossRefGoogle Scholar
  2. Bradford SA, Rathfelder KM, Lang J, Abriola LM (2003) Entrapment and dissolution of DNAPLs in heterogeneous porous media. J Contam Hydrol 67(1–4):133–157CrossRefGoogle Scholar
  3. Chatzis I, Dullien FAL (1983) Dynamic immiscible displacement mechanisms in pore doublets: theory versus experiment. J Colloid Interface Sci 91(1):199–222CrossRefGoogle Scholar
  4. Christ JA, Lemke LD, Abriola LM (2005) Comparison of two-dimensional and three-dimensional simulations of dense nonaqueous phase liquid (DNAPLs): migration and entrapment in a nonuniform permeability field. Water Resour Res 41, W01007. doi:10.1029/2004WR003239
  5. Dekker TJ, Abriola LM (2000a) Influence of field-scale heterogeneity on the infiltration and entrapment of dense nonaqueous phase liquids in saturated formations. J Contam Hydrol 42(2–4):187–218CrossRefGoogle Scholar
  6. Dekker TJ, Abriola LM (2000b) Influence of field-scale heterogeneity on the surfactant-enhanced remediation of entrapped nonaqueous phase liquids. J Contam Hydrol 42(2–4):219–251CrossRefGoogle Scholar
  7. Deutsch CV, Journel AG (1998) GSLIB: geostatistical software library and user’s guide, 2nd edn. Oxford University Press, New YorkGoogle Scholar
  8. Díaz J, Rendueles M, Diaz M (2006) 1,2,4-Trichlorobenzene flow characteristics in saturated homogeneous and stratified porous media. Water Air Soil Pollut 177(1–4):3–17CrossRefGoogle Scholar
  9. Erning K, Shafer D, Dahmke A, Luciano A, Viotti P (2009) Simulation of DNAPL infiltration into groundwater with differing flow velocities using TMVOC combined with PetraSim. Proc. THOUGH Symposium 2009, Lawrence Berkeley National Laboratory, Berkeley, CAGoogle Scholar
  10. Erning K, Shafer D, Dahmke A, Luciano A, Viotti P (2010) Simulation of DNAPL distribution depending on groundwater flow velocities using TMVOC. In: GQ10: groundwater quality management in a rapidly changing world. IAHS Publ. no. 342, IAHS, Wallingford, UKGoogle Scholar
  11. Erning K, Grandel S, Dahmke A, Dehafer D (2012) Simulation of DNAPL infiltration and spreading behavior in the saturated zone at varying flow velocities and alternating subsurface geometries. Environ Earth Sci 65(4):1119–1131CrossRefGoogle Scholar
  12. Fagerlund F, Niemi A, Oden M (2006) Comparison of relative permeability–fluid saturation–capillary pressure relations in the modelling of non-aqueous phase liquid infiltration in variably saturated, layered media. Adv Water Resour 29(11):1705–1730CrossRefGoogle Scholar
  13. Fagerlund F, Illangasekare TH, Niemi A (2007) Nonaqueous-phase liquid infiltration and immobilization in heterogeneous media: 1. experimental methods and two-layered reference case. Vadose Zone J 6(3):471–482CrossRefGoogle Scholar
  14. Falta RW (2003) Modeling sub-grid-block-scale dense non-aqueous phase liquid (DNAPL) pool dissolution using a dual-domain approach. Water Resour Res 39(12):181–187Google Scholar
  15. Falta RW, Press K, Finsterle S, BattistelliA (1995) T2VOC user’s guide. LBL-36400, US Department of Energy, Washington, DCGoogle Scholar
  16. Gerhard JI, Kueper BH (2003) Influence of constitutive model parameters on the predicted migration of DNAPL in heterogeneous porous media. Water Resour Res 39:1279. doi:10.1029/2002wr001570 Google Scholar
  17. Gerhard JI, Pang T, Kueper BH (2007) Time scale of DNAPL migration in sandy aquifers examined via numerical simulation. Ground Water 45(2):147–157CrossRefGoogle Scholar
  18. Kamon M, Endo K, Kawabata J, Inui T, Katsumi T (2004) Two-dimensional DNAPL migration affected by groundwater flow in unconfined aquifer. J Hazard Mater 110(1–3):1–12CrossRefGoogle Scholar
  19. Klute A, Dirksen C (1986) Hydraulic conductivity and diffusivity: laboratory methods. In: Klute A (Farthing, M. W. et al.) Methods of soil analysis, part 1, 2nd edn. Agron. Monograph no. 9, ASA and SSSA, Madison, WI. pp 687–734Google Scholar
  20. Kueper BH, Gerhard JI (1995) Variability of point source infiltration rates for two-phase flow in heterogeneous porous media. Water Resour Res 31(12):2971–2980CrossRefGoogle Scholar
  21. Kueper BH, Stroo HF, Vogel CM, Ward CH (2014) Chlorinated solvent source zone remediation. Springer, Heidelberg, GermanyGoogle Scholar
  22. Lee YK, Khinast J, Kim JH (2007) Numerical modelling of contaminant transport resulting from dissolution of a coal-tar pool in an experimental aquifer. Hydrogeol J 15(4):705–714CrossRefGoogle Scholar
  23. Lemke LD, Abriola LM, Goovaerts P (2004a) Dense nonaqueous phase liquid (DNAPL) source zone characterization: influence of hydraulic property correlation on predictions of DNAPL infiltration and entrapment. Water Resour Res 40, W01511. doi:10.1029/2003WR001980
  24. Liang HL, Falta RW (2008) Modeling field-scale cosolvent flooding for DNAPL source zone remediation. J Contam Hydrol 96(1–4):1–16CrossRefGoogle Scholar
  25. Luciano A, Viotti P, Papini MP (2010) Laboratory investigation of DNAPL migration in porous media. J Hazard Mater 176(1–3):1006–1017CrossRefGoogle Scholar
  26. Luciano A, Viotti P, Papini MP (2012) On morphometric properties of DNAPL sources: relating architecture to mass reduction. Water Air Soil Pollut 223(5):2849–2864CrossRefGoogle Scholar
  27. Marsily GD, Delay F, Goncalves J, Renard P, Teles V, Violette S (2005) Dealing with spatial heterogeneity. Hydrogeol J 13(1):161–183CrossRefGoogle Scholar
  28. Mastrocicco M, Colombani N, Petitta M (2011) Modelling the density contrast effect on a chlorinated hydrocarbon plume reaching the shore line. Water Air Soil Pollut 220(1–4):387–398CrossRefGoogle Scholar
  29. McCray JE, Falta RW (1997) Numerical simulation of air sparging for remediation of NAPL contamination. Ground Water 35(1):99–110CrossRefGoogle Scholar
  30. Morrissey FA, Grismer ME (1999) Kinetics of volatile organic compound sorption/desorption on clay minerals. J Contam Hydrol 36(3–4):291–312CrossRefGoogle Scholar
  31. O’Carroll DM, Bradford SA, Abriola LM (2004) Infiltration of PCE in a system containing spatial wettability variations. J Contam Hydrol 73(1–4):39–63CrossRefGoogle Scholar
  32. Okuda N, Shimizu T, Muratani M, Terada A, Hosomi M (2014) Study of penetration behavior of PCB-DNAPL in a sand layer by a column experiment. Chemosphere 114:59–68CrossRefGoogle Scholar
  33. Oostrom M, Hofstee C, Lenhard RJ, Wietsma TW (2003) Flow behavior and residual saturation formation of liquid carbon tetrachloride in unsaturated heterogeneous porous media. J Contam Hydrol 64(1–2):93–112CrossRefGoogle Scholar
  34. Page JWE, Soga K, Illangasekare TH (2007) The significance of heterogeneity on mass flux from DNAPL source zones: an experimental investigation. J Contam Hydrol 94(3–4):215–234CrossRefGoogle Scholar
  35. Parker JC, Lenhard RJ (1987) A model for hysteric constitutive relations governing multiphase flow, 1: saturation-pressure relations. Water Resour Res 23(12):2187–2196CrossRefGoogle Scholar
  36. Phelan TJ, Lemke LD, Bradford SA, O’Carroll DM, Abriola LM (2004) Influence of textural and wettability variations on predictions of DNAPL persistence and plume development in saturated porous media. Adv Water Resour 27(4):411–427CrossRefGoogle Scholar
  37. Powers SE, Nambi IM, Curry GW (1998) Non-aqueous phase liquid dissolution in heterogeneous systems: mechanisms and a local equilibrium modeling approach. Water Resour Res 34(12):3293–3302CrossRefGoogle Scholar
  38. Pruess K, Battistelli A (2002) TMVOC, a numerical simulator for three-phase non-isothermal flows of multi-component hydrocarbon mixtures in saturated-unsaturated heterogeneous media. LBNL-49375, Lawrence Berkley National Laboratory, Berkeley, CAGoogle Scholar
  39. Schroth MH, Ahearn SJ, Selker JS, Istok JD (1996) Characterization of Miller-similar silica sands for laboratory hydrologic studies. Soil Sci Soc Am J 60(5):1331–1339CrossRefGoogle Scholar
  40. Stone HL (1970) Probability model for estimating three-phase relative permeability. J Pet Technol 22(2):214–218CrossRefGoogle Scholar
  41. Wang XY (2013) Dense nonaqueous phase liquid (DNAPL) source zone characterization in highly heterogeneous permeability fields. Master Thesis, Tufts University, Boston, MA, USAGoogle Scholar
  42. Yang ZB, Zandin H, Niemi A, Fagerlund F (2013) The role of geological heterogeneity and variability in water infiltration on non-aqueous phase liquid migration. Environ Earth Sci 68(7):2085–2097CrossRefGoogle Scholar
  43. Ye SJ, Sleep BE, Chien C (2009) The impact of methanogenesis on flow and transport in coarse sand. J Contam Hydrol 103(1–2):48–57CrossRefGoogle Scholar
  44. Yoon H, Werth CJ, Valocchi AJ, Oostrom M (2008) Impact of nonaqueous phase liquid (NAPL) source zone architecture on mass removal mechanisms in strongly layered heterogeneous porous media during soil vapor extraction. J Contam Hydrol 100(1–2):58–71CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Key Laboratory of Surficial Geochemistry of Ministry of Education, School of Earth Sciences and EngineeringNanjing UniversityNanjingChina

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