Research Title: Removal Of Dense Non-aqueous Phase Liquid From Saturated Porous Media Using Surfactant-alcohol Presenter: Nor Asni binti Azizan Supervisor: Dr. Samira Albati Kamaruddin

Content 1.Introduction – Background of the Problem – Objectives of the Study 2.Literature Review – Types of DNAPL – Transport and Fate of DNAPL – Surfactant-Alcohol – Previous Laboratory Studies – Previous Numerical Simulation Studies 3.Simulation of DNAPL Removal – T2VOC/Tough2 Software 4.Validation of DNAPL Removal – Experimental and Photographic Setup – Image Analysis Technique 5.Research Planning and Schedule 6.Expected Findings

Background of the Problem Dense non-aqueous phase liquid (DNAPL) is a group of liquid that classified as soil and groundwater contaminants when hydrocarbon liquid spills or leaks into the ground. The DNAPL is toxic and hazardous to human, animals and natural habitats. Following this, the researcher has motivated to carry out a study that aimed to investigate the removal of DNAPL. The process will be conducted through numerical simulation and laboratory experiment within two-dimensional (2-D) saturated porous media model by using surfactant alcohol.

DNAPL’s Flow In Subsurface System Table 1: DNAPL’s flow in subsurface system (Davey, Christine A.,1998)

Objectives of the Study To identify the use of surfactant-alcohol flushing for DNAPL removal process in the 2-D model. To investigate the removal of DNAPL in 2-D model of saturated heterogeneous porous media using T2VOC/Tough2 model simulation. To validate model simulation with existing experimental data of DNAPL removal in saturated heterogeneous porous media.

Types of DNAPL Tetrachloroethene (PCE) and trichloroethene (TCE), are some of the most common groundwater contaminants (Fischer et al., 1987; Lucius et al., 1992) Polychlorinated biphenyls (PCBs) Bunker C, a common marine diesel fuel Chlorobenzene, a solvent and chemical Creosote Coal tar Chlorinated solvents

Transport and Fate of DNAPL Density Viscosity Interfacial Tension Wettability Capillary Pressure Saturation Vapor Pressure Volatility Solubility Relative Permeability Residual Saturation

Surfactant-Alcohol Surfactant-alcohol are injected into the subsurface and interact with DNAPL to increase their aqueous solubility, which increases recovery of the chemicals. Surfactant is a compound that decreases liquids surface tension, adsorb at interfaces between air, water and oil and modify the surface properties. Surfactant has been widely used in remediation of DNAPL worldwide. Surfactant remediates DNAPL with solubilization and mobilization mechanism.

Previous Laboratory Studies Types of ModelDNAPL SourceSurfactantPorous MediaReference Micro model 0.013x6.4x4.0, 0.013x5.9x4.2 Soil column 4.8 i.d b Soil column 50 long x 2.42 i.d b Soil column long x 5.08 i.d b Soil column 4.8 i.d b Soil column 15.4 height x 5.0 o.d c Soil column 15.0 height 4mL glass tube 61x91 50mL glass tube Trichloroethylene Polyoxyethylene (20) sorbitan monooleate Automatic transmission fluid 2,3-dimethyl pentane 2,2,4-trimethylpentane 2,2,5-trimethyhexane Tetrachloroethylene 1,2,4-trichlorobenze Dichlorobiphenyl Tetrachloroethylene, Trichloroethylene, Chlorobenzene, 1,2-dichlorobenzene 1,1,2-trichloroethane Tetrachloroethylene, Trichloroethylene Hydrophobic dye, DO-11 Sodium C olefin sulfonate 14 C-labelled dodecane Alcohol ethoxylate Hexadecyl (C16) diphenyl oxide disulfonate Polyoxyethylene Sodium, diamyl, dioctyl, dihexyl sulfosuccinate Sodium diphenyl oxide disulfonate Polyoxyethylene (23) laurl ether, Polyoxyethylene (20) sorbitan monooleate, Sodium dodecyl sulfate Pure-hydrophobe primary alcohol ethoxylates, Witconol SN-120 primary alcohol ethoxylate, etc Polyoxyethylene (20) sorbitan monooleate, Polyoxyethylene (23) laurl ether Homogeneous Homogeneous Homogeneous Heterogeneous Homogeneous Homogeneous Heterogeneous Heterogeneous Homogeneous Heterogeneous (Jeong et al., 2000), (Jeong and Corapcioglu, 2005)Jeong et al., 2000Jeong and Corapcioglu, 2005 (Abriola et al., 1993)Abriola et al., 1993 (Ang and Abdul, 1991)Ang and Abdul, 1991 (Sabatini et al., 1997)Sabatini et al., 1997 (Pennell et al., 1994)Pennell et al., 1994 (Lee et al., 2002)Lee et al., 2002 (Chu and Kwan, 2003)Chu and Kwan, 2003 (Cowell et al., 2000)Cowell et al., 2000 (Saenton et al., 2002)Saenton et al., 2002 (Chu, 2002)Chu, 2002

Previous Numerical Model Simulation Studies Numerical models have been formulated to simulate the flow of DNAPLs and their interactions with surfactant in the subsurface. Solute movement through heterogeneous porous media containing residual saturation was modeled by Hatfield and Stauffer in The simulated injection of isopropyl alcohol (IPA) was shown to increase the recovery of PCE in a horizontal, one-dimensional porous medium (Reitsma and Kueper, 1996). Surfactant flooding has been simulated by modifying a three-dimensional finite-difference enhanced oil recovery package (Brown and Pope, 1994). Three-dimensional simulations of DNAPLs in heterogeneous saturated and unsaturated porous media have also been performed using the multiphase flow package T2VOC (Falta et al., 1995; Hodges and Falta, 1996). Brame developed a three-dimensional multiphase simulator, ALCLFD, which combines heterogeneous and alcohol/water/DNAPL ternary phase systems (Brame, 1993).

T2VOC/Tough2 Software T2VOC is a TOUGH module for three-phase flow of water, air, and a volatile organic compound (VOC). T2VOC was designed to simulate processes such as – The migration of hazardous non-aqueous phase liquids (NAPLs) in variably saturated media – Forced vacuum extraction of organic chemical vapors from the unsaturated zone (soil vapor extraction) – Evaporation and diffusion of chemical vapors in the unsaturated zone – Air injection into the saturated zone for removal of volatile organics (air sparging) – Direct pumping of contaminated water and free product – Steam injection for the removal of NAPLs from contaminated soils and aquifers.

Research Design and Procedure

Experimental and Photographic Setup An experimental setup of the multiphase flow experiment consists of 2-D model fabrication, porous media and DNAPL source preparation, and fluid content sensors and probes. The sand tank is placed with the glass wall facing a camera. Only the tank and two 500-W tungsten filament floodlights will be placed inside the black curtain. The position of the lighting sources is carefully adjusted to avoid reflection from the lighting stand and the soft box’s flash, and to produce constant lighting for the entire flow region.

Image Analysis Technique The procedures facilitated by the Image Pro-Plus software. The image is registered to a grid mask representing the actual dimensions of the sand tank. Each image will be calibrated to the actual measurement and median smoothing is assigned to all images to remove impulse noise from images. The average optical density of the AOI is measured using the Bitmap Analysis tool and the data is extracted to an Excel spreadsheet for DNAPL and water saturation calculation. The data then used will be visualize in the shape of contour map using the Surfer software.

Research Planning and Schedule

Expected Findings Solubilization and mobilization is the dominant process in DNAPL removal using surfactant alcohol. The successful rate of removal shall be more than 95% successful. The numerical model simulation shall validate the existing experimental data or the extraction of data from laboratory experiment using the IPP.

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