• Title, Summary, Keyword: soil column

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Containing Heavy Metal Contaminants Using Soil-Cement Column Barrier (심층혼합기둥체 차수벽을 이용한 중금속 오염물질의 이동 제어)

  • 정문경;천찬란;이주형;김강석
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.821-826
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    • 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.

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Removal of $NH_4-N$ from Synthetic Wastewater Using Soil Column (토양컬럼을 이용한 합성폐수중의 암모니아성질소 제거)

  • Park San Ill;Cheong Kyung Hoon;Kim Hai Yeon;Paik Ke Jin
    • Journal of Environmental Health Sciences
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    • v.31 no.4
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    • pp.280-286
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    • 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 ($20\%$).

Electrokinetic Remediation of Cobalt Contaminated Soil (코발트 오염토양 동전기적 제염)

  • 김계남;오원진
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.290-293
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    • 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.

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Effect of the Presence of Soil on the Ferrous Catalyzed Sodium Persulfate Oxidation of Naphthalene (과황산나트륨과 제일철 촉매를 이용한 나프탈렌 산화 시 토양이 미치는 영향 평가)

  • Han, Dai-Sung;Yun, Yeo-Bog;Ko, Seok-Oh
    • Journal of Soil and Groundwater Environment
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    • v.15 no.1
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    • pp.29-38
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    • 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.

Soil Column Experiment to Evaluate Removal of Nutrients in Stormwater Runoff by Soil of Riparian Protection Zone (토양칼럼을 이용한 초기우수 중 염양염류의 수변녹지 토양에서의 제거도 평가)

  • Yoon, Seok-Pyo;Choi, Ji-Yong
    • Journal of Korean Society on Water Environment
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    • v.20 no.3
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    • pp.231-235
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    • 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.

Pseudostatic Analysis of Single Column/Shafts Considering Nonlinear Soil Behavior (지반의 비선형거동을 고려한 단일현장타설말뚝의 의사정적해석)

  • Lee, Joon-Kyu;Kim, Byung-Chul;Jeong, Sang-Seom;Song, Sung-Wook
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.1C
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    • pp.31-40
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    • 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.

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Simultaneous Removal of Heavy Metals and Diesel-fuel from a Soil Column by Surfactant Foam Flushing (계면활성제 거품(Foam)을 이용한 토양칼럼 내 유류 및 중금속 동시 제거 연구)

  • Heo, Jung-Hyun;Jeong, Seung-Woo
    • 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.

Nitrogen Removal from Synthetic Domestic Wastewater Using the Soil Column (토양컬럼을 이용한 합성하수 중의 질소제거)

  • Cheong, Kyung-Hoon;Lim, Byung-Gab;Choi, Hyung-Il;Park, Sang-Ill;Moon, Ok-Ran
    • Journal of Environmental Science International
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    • v.16 no.6
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    • pp.707-714
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    • 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.

Changes of Performance of Soil-Cement Barrier due to Migration of Acids (산 이동에 따른 심층혼합기둥체 차수벽의 성능변화)

  • 정문경;천찬란;이주형;김강석
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.189-196
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    • 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.

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Field behaviour geotextile reinforced sand column

  • Tandel, Yogendra K.;Solanki, Chandresh H.;Desai, Atul K.
    • Geomechanics and Engineering
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    • v.6 no.2
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    • pp.195-211
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    • 2014
  • Stone columns (or granular column) have been used to increase the load carrying capacity and accelerating consolidation of soft soil. Recently, the geosynthetic reinforced stone column technique has been developed to improve the load carrying capacity of the stone column. In addition, reinforcement prevents the lateral squeezing of stone in to surrounding soft soil, helps in easy formation of stone column, preserve frictional properties of aggregate and drainage function of the stone column. This paper investigates the improvement of load carrying capacity of isolated ordinary and geotextile reinforced sand column through field load tests. Tests were performed with different reinforcement stiffness, diameter of sand column and reinforcement length. The results of field load test indicated an improved load carrying capacity of geotextile reinforced sand column over ordinary sand column. The increase in load carrying capacity depends upon the sand column diameter, stiffness of reinforcement and reinforcement length. Also, the partial reinforcement length about two to four time's sand column diameter from the top of the column was found to significant effect on the performance of sand column.