PDF(1537 KB)
PDF(1537 KB)
PDF(1537 KB)
裂隙地下水中残留LNAPL物理驱替冲洗实验
Physical displacement and flush of entrapped LNAPL in fractured media groundwater
利用透明复制裂隙模型，选择两种典型LNAPL（轻非水相液体）-邻二甲苯和十二烷残留体，开展一系列水流驱替冲刷和SDS（十二烷基磺酸钠）表面活性剂增强驱替实验，直接获取了裂隙内部LNAPL残留体几何形状与分布情况，结果表明：水流驱替冲刷和SDS驱替裂隙内残留体的去除率分别为8.3%~12.3%和65.9%~82.1%.残留体累积去除率随着驱替流体雷诺数的增加而增加.水流驱替冲刷条件下，残留体离散为小液滴，数量比初始残留状态增加1.3~2.2倍.SDS表面活性剂降低了"LNAPL-水"间的界面张力，能够有效去除裂隙内较大残留体，驱替后仅残余单个面积为1mm2左右的微小液滴.由于粗糙裂隙的非均质性，水流冲刷易导致系统内的"LNAPL-水"有效界面面积增加，对LNAPL污染修复不利，表面活性剂增强修复是一种更有效的方法.
With the transparent replica fracture model, two typical LNAPL (light non-aqueous phase liquid) pollutants o-xylene and dodecane) were selected to be flushed by water and the SDS (sodium dodecyl sulfonate) solution. The geometry and distribution of the entrapped LNAPL were obtained directly in a series of experiments. The results showed that the removal percentage of the entrapped LNAPL flushed by water and the SDS solution were in the ranges of 8.3%~12.3% and 65.9%~82.1%, respectively. The cumulative removal percentage were increased with increasing Reynolds number of the flushing fluids. Under the water flushing condition, the entrapped blobs were dispersed into smaller droplets, and the droplet numbers were increased by 1.3~2.2times compared with the initial states. SDS surfactant reduced the interfacial tension between LNAPL and water, thus it can effectively remove the larger entrapped blobs in the fracture. After SDS displacement, only small droplets with a single area of about 1mm2 remained. Because of the heterogeneity of variable-aperture fractures, water flush was demonstrated to result in the increase of the effective interface area of ‘LNAPL-water’ in the system, which was disadvantageous to the remediation of LNAPL pollutants. Surfactant enhanced displacement could be a more effective method for LNAPL removal.
表面活性剂 / 地下水 / 非水相液体(NAPL) / 裂隙介质 / 物理驱替
fractured media / groundwater / non-aqueous phase liquid / physical displacement / surfactant
[1] 刘玉兰,程莉蓉,丁爱中,等.NAPL泄漏事故场地地下水污染风险快速评估与决策[J]. 中国环境科学, 2011,31(7):1219-1224. Liu Y L, Cheng L R, Ding A Z, et al. Quick assessment of groundwater risk after NAPL spill and its application in site emergency management[J]. China Environmental Science, 2011,31(7):1219-1224.
[2] Essaid H I, Bekins B A, Cozzarelli I M. Organic contaminant transport and fate in the subsurface:Evolution of knowledge and understanding[J]. Water Resources Research, 2015,51(7):4861-4902.
[3] 高存荣,王俊桃.我国69个城市地下水有机污染特征研究[J]. 地球学报, 2011,32(5):581-591. Gao C R, Wang J T. Research on groundwater organic contamination characteristics in 69cities of China[J]. Acta Geoscientica Sinica, 2011,32(5):581-591.
[4] Mao X, Jiang R, Xiao W, et al. Use of surfactants for the remediation of contaminated soils:a review[J]. Journal of hazardous materials, 2015,285:419-435.
[5] O'Carroll D, Sleep B, Krol M, et al. Nanoscale zero valent iron and bimetallic particles for contaminated site remediation[J]. Advances in Water Resources, 2013,51:104-122.
[6] Fedrizzi F, Ramos D T, Lazzarin H S C, et al. A modified approach for in situ chemical oxidation coupled to biodegradation enhances light nonaqueous phase liquid source-zone remediation[J]. Environmental Science & Technology, 2016,51(1):463-472.
[7] Tan Y, Lu B, Wu T, et al. Flow and Solute Transport through a Single Fracture during the Biodegradation of Residual Toluene[J]. Journal of Applied Fluid Mechanics, 2017,10(6):1669-1677.
[8] Lenhard R J, Oostrom M, Dane J H. A constitutive model for air-NAPL-water flow in the vadose zone accounting for immobile, non-occluded (residual) NAPL in strongly water-wet porous media[J]. Journal of Contaminant Hydrology, 2004,73(1):283-304.
[9] Yang Z, Niemi A, Fagerlund F, et al. Dissolution of dense non-aqueous phase liquids in vertical fractures:Effect of finger residuals and dead-end pools[J]. Journal of Contaminant Hydrology, 2013,149:88-99.
[10] 郑菲,高燕维,施小清,等.地下水流速及介质非均质性对重非水相流体运移的影响[J]. 水利学报, 2015,46(8):925-933. Zheng F, Gao Y W, Shi X Q, et al. Influence of groundwater flow velocity and geological heterogeneity on DNAPL migration in saturated porous media[J]. Journal of Hydraulic Engineering, 2015, 46(8):925-933.
[11] 卢斌,吴时强,谈叶飞,等.单裂隙中LNAPL残留特点及残留体对水流运动的影响[J]. 水科学进展, 2015,26(1):107-113. Lu B, Wu S Q, Tan Y F, et al. Characterization of residual LNAPL and effect of LNAPL entrapment configuration on water flow in a single fracture[J]. Advances in Water Science, 2015,26(1):107-113.
[12] 邓亚平,张烨,施小清,等.非均质裂隙介质中重非水相流体运移[J]. 水科学进展, 2015,26(5):722-730. Deng Y P, Zhang Y, Shi X Q, et al. Study on the migration of dense non-aqueous phase liquids in heterogeneous fractured media[J]. Advances in Water Science, 2015,26(5):722-730.
[13] 赵科锋,王锦国.包气带中裂隙对轻非水相流体运移和分布影响的模拟研究[J]. 水利学报, 2016,47(7):891-899. Zhao K F, Wang J G. Simulation of fracture impacts on light non-aqueous phase liquids migration liquids migration and distribution in the unsaturated zone[J]. Journal of Hydraulic Engineering, 2016,47(7):891-899.
[14] 肖岳峰,王锦国,黄倩,等.LNAPL在含裂隙层状非均质地层中运移模拟研究[J]. 水文地质工程地质, 2017,44(1):23-30. Xiao Y F, Wang J G, Huang Q, et al. A simulation study of LNAPL migration in layered heterogeneous porous media containing fractures[J]. Hydrogeology & Engineering Geology, 2017,44(1):23-30.
[15] Lu B, Wu S, Xie X, et al. The behaviors of LNAPL migration and entrapment in a rough-walled vertical fracture[J]. Geosciences Journal, 2017,21(3):407-416.
[16] Longino B L, Kueper B H. Nonwetting phase retention and mobilization in rock fractures[J]. Water Resources Research, 1999, 35(7):2085-2093.
[17] 郭琼泽,张烨,姜蓓蕾,等.表面活性剂增强修复地下水中PCE的砂箱实验及模拟[J]. 中国环境科学, 2018,38(9):200-207. Guo Q Z, Zhang Y, Jiang B L, et al. Experiment and numerical simulation of surfactant-enhanced aquifer remediation in PCE contaminated laboratory sandbox[J]. China Environmental Science, 2018,38(9):200-207.
[18] 程洲,吴吉春,徐红霞,等.DNAPL在透镜体及表面活性剂作用下的运移研究[J]. 中国环境科学, 2014,34(11):2888-2896. Chen Z, Wu J C, Xu H X, et al. investigation of the migration characteristic of DNAPL in aquifer with lenses and under the action of surfactant flushing[J]. China Environmental Science, 2014,34(11):2888-2896.
[19] Lee H B, Yeo I W, Ji S H, et al. A capillary number for physical displacement of TCE-DNAPL trapped in a rough-walled fracture[J]. Geosciences Journal, 2011,15(3):305-311.
[20] Zhong L, Mayer A. Visualization of surfactant-enhanced nonaqueous phase liquid mobilization and solubilization[J]. Water Resources Research, 2001,37(3):523-537.
[21] Wan J, Tokunaga T K, Orr T R, et al. Glass casts of rock fracture surfaces:A new tool for studying flow and transport[J]. Water Resources Research, 2000,36(1):355-360.
[22] Detwiler R L, Pringle S E, Glass R J. Measurement of fracture aperture fields using transmitted light:An evaluation of measurement errors and their influence on simulations of flow and transport through a single fracture[J]. Water Resources Research, 1999,35(9):2605-2617.
[23] Nowamooz A, Radilla G, Fourar M, et al. Non-Fickian transport in transparent replicas of rough-walled rock fractures[J]. Transport in Porous Media, 2013,98(3):651-682.
[24] Brush D J, Thomson N R. Fluid flow in synthetic rough-walled fractures:Navier-Stokes, Stokes, and local cubic law simulations[J]. Water Resources Research, 2003,39(4):1-15.
[25] 王栋,李静,吕建晓,等.表面活性剂环境模拟水相粘度温度响应及热力学解析[J]. 大连理工大学学报, 2005,45(4):527-530. Wang D, Li J, Lv J X, et al. Temperature response and thermodynamic analysis of aqueous viscosity in surfactant environment[J]. Journal of Dalian University of Technology, 2005,45(4):527-530.
国家自然科学基金资助项目（51709184，41831278）；中国博士后基金资助项目（2018M630577）；中央级公益性科研院所基本科研业务费专项（Y118008）
京公网安备 11010802030352号 /
| 〈 |
|
〉 |
