• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.821-826
• /
• 2003

Laboratory experiments were peformed to understand physical properties of soil-cement column under the influence of acidic flow including metal contaminants and its retaining capacity against metal migration. The contaminant used in this study was nitric acid with Cu and Cd. The Permeability of soil-cement column decreased when pH of the column began to drop below 12. Decreases in pH led to significant reduction of compressive strength of clayey soil-cement specimen, while relatively marginal reduction for sandy soil-cement specimen. The metal contaminants did not leachate from soil-cement column until pH of soil-cement dropped below 7∼8 for Cu and 9∼10 for Cd. Metal contaminants were precipitated and trapped inside the soil-cement column at pHs higher than those mentioned as verified with metal analysis and visual inspection. This indicated that soil-cement column not only performs well as a cut-off wall, but also helps alleviating the level of contamination of the surrounding environment.

• Journal of Environmental Health Sciences
• /
• v.31 no.4 s.85
• /
• pp.280-286
• /
• 2005

The purpose of this investigation was to evaluate removal efficiency of $NH_4-N$ using the soil column. Soil, oyster shell and natural zeolite were used as a supporting media of soil column. Removal efficiencies of $NH_4-N$ were $35.9\%,\;41\%\;and\;93.4\%$ for the soil column packed with soil, natural $zeolite(20\%)$ and oyster $shell(20\%)$ at HRT of 72 hours, respectively. The addition of $20\%$ oyster shell to the soil accelerated nitrification in soil column. The influent ammonia nitrogen was mostly converted to nitrate nitrogen in the soil column and little ammonia nitrogen was found in the effluent. When the influent $NH_4-N$ concentration was 200 mg/l, the NIL-N removal was decreased at HRT of 48 hours, while nitrification was significantly increased after mechanical aeration. It was suggested that nitrification from higher $NH_4-N$ concentration was more affected by aeration in soil column process. The number of nitrifiers was approximately in a level of about $10^6\;MPN/g{\cdot}soil$ in the soil column mixed with oyster shell ($20\%$).

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.290-293
• /
• 2000

After kaolin clay was compulsorily contaminated with Co$^{2+}$ion, the remediation characteristics by electrokinetic method were analyzed. Ethanoic buffer was injected in the soil column and $CH_3$COOH was continuously inputted in cathode reservoir to restrain the pH elevation. Since pH of the cathode side of the soil column was 4.0 at initial and was restrained by 6.5 at 43.6 hours, Precipitation, Co(OH)$_2$, was not formed in the column. Effluent rate increased with time passage and remediation in the column in initial time was mainly controlled by ion migration. 13.1% of total in the soil column was remediated in 10 hours, and the 6.8% of total in 20.8 hours, and the 71.7% of total in 43.6 hours, and the 94.6% of total in 43.6 hours. Meanwhile, the residual concentrations in the column calculated by the developed model were similar to those by experiment.t.

• Journal of Soil and Groundwater Environment
• /
• v.15 no.1
• /
• pp.29-38
• /
• 2010

Batch tests were carried out to examine the influence of the presence of soil and Fe(II) sorption capacity of soil on the ferrous catalyzed sodium persulfate oxidation for the destruction of organic pollutants in the application of in-situ chemical oxidation. Laboratory column tests were also conducted to investigate the transport of oxidant and catalyst in contaminated groundwater. Test results proved that Fe(II) was adsorbed on soil surface, and thus soil behaved as a heterogeneous catalyst, enhancing the naphthalene removal rate up to 50%. Column tests that were conducted with and without dissolved Fe(II) showed that naphthalene removal ratio were 24% and 25%, respectively. The removal efficiency was not enhanced with dissolved Fe(II), since the dissolved Fe(II) flew out of the column as the oxidant progressively injected into the column saturated with Fe(II). It indicates that the injected oxidant could not interact with dissolved Fe(II). But target organic pollutant was degraded in soil column system, implying that sulfate radical was produced by the reaction of dissolved persulfate with Fe(II) adsorbed on soil.

• Journal of Korean Society on Water Environment
• /
• v.20 no.3
• /
• pp.231-235
• /
• 2004

To investigate removal effects of nutrients in stormwater runoff by soil of riparian protection zone, soil column experiment was conducted for 20 months. Artificial stormwater runoff containing phosphate and nitrate was applied on the surface of soil column twice a week, and phosphate and nitrate concentrations were measured from the leached water. Soil of riparian protection zone reduced the released amount of infiltrated water to the surrounding water. After infiltration of 1m depth of soil column, average removal rates of phosphate and nitrate were 97.7 % and 74.7 %, respectively. As main mechanisms of phosphate are adsorption to soil particle and utilization by plants, periodical replacement of soil and harvesting of plant at the end of growing season are required. For the removal of nutrients in stormwater runoff by the soil layer, soil of riparian protection zone has higher hydraulic conductivity to infiltrate stormwater. Sandy soil having hydraulic conductivity of about $1{\times}10^{-2}cm/s$ range might be appropriate for this purpose.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.1C
• /
• pp.31-40
• /
• 2008

This study presents the assessment of pseudostatic approach for obtaining the internal response of Single Column/Shaft subjected to earthquake loading. In numerical procedure, various lateral load transfer characteristics (p-y curve and Bi-linear curve) were used to model the nonlinear behavior of soil reactions including soil-pile interaction. The analysis using nonlinear soil model could estimate the seismic performance of soil-pile system, despite its relative simplicity. It was found that lateral behavior of single column/shaft obtained from the response displacement method was larger than those by seismic intensity method. To investigate the effects of soil-pile rigidity and pile head condition on the internal pile response, parametric studies were carried out for various soil models. The results from numerical analysis showed that lateral deflection was decreased with fixed condition of pile head and decreasing the soil-pile rigidity. The seismic analysis using Bi-linear model of JRA could reasonably predict the lateral behavior of Single Column/Shaft.

• Journal of Soil and Groundwater Environment
• /
• v.16 no.5
• /
• pp.90-96
• /
• 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 Environmental Science International
• /
• v.16 no.6
• /
• pp.707-714
• /
• 2007

A laboratory experiment was performed to investigate nitrogen removal by the soil column. The addition of 20% waste oyster shell to the soil accelerated nitrification in soil column. The $NO_3^--N$ concentration in the effluent decreased with the decrease of HRT(Hydraulic Retention Time). When methanol and glucose added as carbon sources, the average removal rates of T-N(Total Nitrogen) were 82% and 77.9%, respectively. The $NO_3^--N$ removal by methanol supplementation in soil column can likely be attributed to denitrification. In continuous removal of nitrogen using the soil column, the COD(Chemical Oxygen Demand) and $NH_4^+-N$ removed simultaneously in organic matter decomposing column. The greater part of $NH_4^+-N$ was nitrified by the percolated through nitrification column, and the little $NH_4^+-N$ was found in the effluent. The T-N of 87.4% removed at HRT of 36 hrs in denitrfication column. Because of nitrified effluents from nitrification column are low in carbonaceous matter, an external source of carbon is required.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.189-196
• /
• 2003

Soil-cement column is often used as a contaminant barrier. This study presents the results of experimental study performed to investigate the changes of properties of soil-cement column under the attack of acids. Sulfuric nitric, and ascetic acid were used as contaminants. Specimen were made of clayey and sandy soils with addition of cement and water Permeability of soil-cement decreased with time during permeability test. When significant amount of acid percolated the specimen, permeability increased and compressive strength decreased due to the dissolution and leaching of cement and its chemical reaction compounds. Sulfuric and nitric acid were more effective than ascetic acid in deteriorating soil-cement column. Amount of acid required to lower the pH of soil cement below 12 was calculated from the results of permeability tests. This leads to a conclusion that, under the conditions employed in this study, the chemical stability of soil-cement column could be maintained against acid attack for longer than generally accepted lifetime of contaminant barriers.

• Earthquakes and Structures
• /
• v.24 no.4
• /
• pp.289-301
• /
• 2023

Developing a competent soil-bridge interaction model for the seismic analysis of piled foundation bridges is of utmost importance for investigating the seismic response and assessing fragility of these lifeline structures. To this end, ground motion histories are deemed necessary at various depths along the piles supporting the bridge. This may be effectively accomplished through time history analysis of a free-field standalone soil column extending from bedrock level to ground surface subjected to an input bedrock motion at its base. A one-dimensional site/ground response analysis (vide one-directional shear wave propagation through the soil column) is hence conducted in the present research accounting for the nonlinear hysteretic behavior of the soil stratum encompassing the bridge piled foundation. Two homogeneous soil profiles atop of bedrock have been considered for comparison purposes, namely, loose and dense sand. Analysis of the standalone soil column has been performed under a set of ten selected actual bedrock ground motions adopting a nonlinear time domain approach in an incremental dynamic analysis framework. Amplified retrieved PGA and maximum soil shear strains have been generally observed at various depths of the soil column when moving away from bedrock towards ground surface especially at large hazards associated with high (input) PGA values assigned at bedrock. This has been accompanied, however, by some attenuation of the amplified PGA values at shallower depths and at ground surface especially for the loose sand soil and particularly for cases with higher seismic hazards associated with large scaling factors of bedrock records.