• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.90-96
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• 2011

Simultaneous removal of heavy metals (Cd, Pb) and diesel-fuel from a soil column was evaluated by respectively flushing with sodium dodecyl sulfate (SDS) solution, mixture of SDS and sodium iodide (SDS + NaI), and surfactant foam (SDS + NaI foam). First, this study evaluated these flushing methods to the heavy metals only-contaminated soil for removal of heavy metals from the heavy-metal only contaminated soil column. After 7 pore volume flushing of the soil column, Cd removal efficiencies from the soil were 40% by SDS solution, 50% by SDS + NaI mixture, and 60% by surfactant foam. The flushing results implied that anionic surfactant and ligand can be efficiently applied to extraction of Cd from the heavy metal contaminated soil. Furthermore, surfactant foam flushing showed an increased flushing efficiency with enhancing the contact between surfactant solution and soil. However, Pb removal efficiency by these flushing methods did not show any difference unlike those of Cd. Second, this study eventually evaluated flushing methods for simultaneous removal of heavy metals and diesel-fuel from the soil column with 7 pore volume flushing. Diesel-fuel removal efficiencies were 50% by SDS + NaI flushing and 90% by SDS + NaI foam flushing. Cd removal efficiency by the foam flushing reached to 80% which was higher than the result of the previous heavy metals onlycontaminated soil experiment. This result implied that diesel-fuel could act as a metal-solvent while it contacted to heavy metals present in the soil. This study clearly showed that surfactant foam flushing simultaneously removed heavy metals and diesel fuel from the soil column.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.824-830
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• 2006

Several tests were conducted to optimize the design parameters of ln-situ soil flushing processes for diesel contaminated soil. According to the batch extraction test for three anionic surfactants evaluation, Calgonit limiting bubble occurrence was selected for its higher oil cleaning efficiency. After optimum surfactant selection, there were many sets of column flushing test. Over 70% of BTEX was removed in this surfactant dose with 400% of soil volume. In the case of no surfactant addition flushing in column, so called "blank flushing test", BTEX removal rate was 64%. But when we reused the effluent for the cleaning solution, the removal rate was decreased to 46.9%. This result showed reabsorption of oil occurred on the soil. With the addition of Calgonit solution to the diesel contaminated column, BTEX was removed up to 98.9% during the first flushing and 99.4% for the second recirculation flushing. In microcosm tests, diesel contaminated soils were cleaned by both surfactant flushing and biological activities. In anoxic condition, nitrate was used as an electron acceptor while the surfactant and the oil were used an electron donor. BTEX removal efficiency could be achieved up to 80% by biological degradation.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.291-300
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• 1999

Surfactant flushing for enhancing the removal of BTEX from contaminated sand/clay mixtures was investigated. Eight soil columns packed with relatively undisturbed BTEX contaminated soils, were leached with water, methyl alcohol and then flushed with surfactant with or without several additives. Initial concentrations of BTEX mixture range from 278mg/kg to 1975mg/kg. Initial BTEX removal efficiency was 98% when the contaminated soil was flushed with water of 850 pore volumes. Because of tailing effect, water flushing could not remove below 8mg/kg concentrations during the experimental period. Eventually, the most effective surfactant for flushing was turned out to be 4% SOFTANOL(equation omitted)-90 with 3% ethyl alcohol and 3% SXS. In interrupted flow conditions, the removal efficiency was 99.5% with the flushed water of 95 pore volumes. The BTEX mixture removed from the soil columns during the surfactant flushing ranges from 84.5% to 99.5% of the initial amount for both water leaching(850 pore volumes) and surfactant flushing(95-165 pore volumes), respectively. Test results indicated that surfactant flushing could enhance the removal of BTEX mixture from contaminated soils and could reduce the aqueous phase BTEX mixture concentration in leachate.

• Journal of Soil and Groundwater Environment
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• v.21 no.5
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• pp.1-7
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• 2016

The removal of non-aqueous phase liquids (NAPLs) from groundwater using pure water, via pump and treat, is quite ineffective due to their low solubility and hydrophobicity. Therefore, the objectives of pilot tests were to select potentially suitable surfactants that solubilize tetrachloroethylene (PCE) and trichloroethylene (TCE) present as contaminants and to evaluate the optimal range of process parameters that can increase the removal efficiency in surfactant-enhanced soil flushing (SESF). Used experimental method for surfactant selection was batch experiments. The surfactant solution parameters for SESF pilot tests were surfactant solution concentration, surfactant solution pH, and the flow rate of surfactant solution in the SESF pilot system. Based on the batch experiments for surfactant selection, DOSL (an anionic surfactant) was selected as a suitable surfactant that solubilizes PCE and TCE present as contaminants. The highest recovery (95%) of the contaminants was obtained using a DOSL surfactant in the batch experiments. The pilot test results revealed that the optimum conditions were achieved with a surfactant solution concentration of 4% (v/v), a surfactant solution pH of 7.5, and a flow rate of 30 L/min of surfactant solution (Lee and Woo, 2015). The maximum removal of contaminants (89%) was obtained when optimum conditions were simultaneously met in pilot-scale SESF operations. These results confirm the viability of SESF for treating PCE and TCE-contaminated groundwater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.418-421
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• 2003

Surfactant enhanced in-situ soil flushing was peformed to remediate the soil and groundwater at an oil contaminated site, and the effluent solution was treated by the chemical treatment process including DAF(Dissolved Air Flotation). A section from the contaminated site(4.5m$\times$4.5m$\times$6.0m) was selected for the research, which was composed of heterogeneous sandy and silt-sandy soils with average Hydraulic conductivity of 2.0$\times$10$^{-4}$ cm/sec. Two percent of sorbitan monooleate(POE 20) and 0.07% of iso-prophyl alcohol were mixed for the surfactant solution and 3 pore volumes of surfactant solution were injected to remove oil from the contaminant section. Four injection wells and two extraction wells were built in the section to flush surfactant solution. Water samples taken from extraction wells and the storage tank were analyzed by GC(gas-chromatography) for TPH concentration with different time. Five pore volumes of solution were extracted while TPH concentration in soil and groundwater at the section were below the Waste Water Discharge Limit(WWDL). Total 18.5kg of oil (TPH) was removed from the section. The concentration of heavy metals in the effluent solution also increased with the increase of TPH concentration, suggesting that the surfactant enhanced in-situ flushing be available to remove not only oil but heavy metals from contaminated sites. Results suggest that in-situ soil flushing and chemical treatment process including DAF could be a successful process to remediate contaminated sites distributed in Korea.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.215-218
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• 2005

We applied the density-surfactant-motivated method to the removal of DNAPL within a rough-walled single fracture. Observations are made to compare the DNAPL residual distribution before and after the flushing of surfactant-enhanced solution or water flushing. Results show that density-motivated method with surfactant-enhanced solution effectively removed DNAPL in a single fracture.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.51-54
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• 2003

Three kinds of experiments were conducted to test existing methods and develop an effective methodology for the remediation of DNAPL trapped in vertical dead-end fractures. A water-flushing method failed to remove TCE from vertical dead-end fractures where no fluid flow occurs. A water-flushing experiment implies that existing remediation methods, utilizing water-based remedial fluid such as surfactant-enhanced method, have difficulty in removing DNAPL trapped from the vertical downward dead-end fractures, because of no water flow through dead-end fractures, capillary, and gravity forces. Fluid denser than TCE was injected into the fracture network, but did not displace TCE from the vertical dead-end fractures. Base(B on the analysis of the experiments, the increase in the density of the dense fluid and the addition of surfactant to the dense fluid were suggested, and this composite dense fluid with surfactant effectively removed TCE from the vertical dead-end fractures.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.2
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• pp.82-90
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• 2004

This study was conducted to evaluate in situ soil flushing and coagulation for naphtalenes-contaminated soil remediation. Mixed-surfactant of 1% POE12 and 1% SDS (1 : 1 by volume basis) was used as a flushing solution. When 5 pore volumes of mixed -surfactant were added to soil column, the flushing efficiencies of 2-methylnaphtalene and 1,5-dimethylnaphtalene with about 1,500 mg/kg(dry soil) were approximately 80% and 60% respectively. In adding 13 pore volumes of mixed-surfactant, the flushing efficiencies of 2-methylnaphtalene and 1,5-dimethylnaphtalene were 90% and 82%. However, considering in situ soil flushing with distilled water, about 42% and 71% were flushed for 2-methylnaphtalene and 1,5-dimethylnaphtalene by surfactant-only. For about 10,000 mg/kg(dry soil) diesel-contaminated soil, 40% and 70% of TPH were flushed-out in 5 pore volumes and 13 pore volumes addition. However, for naphtalenes in diesel TPH, 90% of flushing efficiency was discovered in adding only 5 pore volumes of flushing solution. There was not discovered significant difference among coagulation efficiencies of 6 kinds of polymers, and the coagulation efficiencies were near 50%.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.17-23
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• 2011

In this study, a series of experiments were carried out to remove total petroleum hydrocarbon(TPH) and toluene by soil flushing. In batch experiments, Triton X-100 and SWA 1503 showed TPH removal efficiency of 79.0% and 69.0%, respectively. Although the TPH removal efficiency increased as the surfactant was increased in the concentration range 1-11mmol/L, the optimum concentration was 1mmol/L, considering the ratio of the removal efficiency to the amount of surfactant injected. In column experiment, the optimal velocity was 0.3mL/min. The physical aquifer model(PAM) result revealed that the soil flushing removed as much as 5.5% of the toluene under 3 pore volume(PV) conditions. To improve the soil flushing efficiency, it is necessary to find optimal condition through recirculation or reuse of surfactant.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.96-98
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• 2000

Column experiments were peformed to evaluate the efficiency of surfactant flushing for remediation of non-aqueous phase liquid (NAPL) in the soil under controlled conditions. In column experiment less than 0.1 % of the original mass of tetrachloroethylene (PCE), remained in the column after 15 pore volumes of 1% sorbitan monooleate solution were passed through columns. To determine the influence of soil parameters that may affect the remediation process, column tests were repeated with different values of grain size, application rate, surfactant type, surfactant concentration, and solution viscosity (polymer mixed with surfactant). Experimental works suggest that surfactant flushing has a great potential to rapidly remove mass from NAPL in the soil.