• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.62-65
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• 2002

Permeable reactive barriers (PRBs) are in-situ barriers constructed in a subsurface to treat contaminated groundwater using various reactive media. The common reactive medium used in PRB is zero-valent iron, which has been widely used to treat chlorinated solvents (i.e., PCE, TCE). A disadvantage of iron media is high cost. In this study, waste foundry sands were tested to determine the feasibility of their use as a low cost reactive medium. Batch and column tests were conducted with TCE to determine transport parameters and reactivity of the foundry sands. The reactivities of foundry sands for common groundwater contaminants are comparable to or slightly higher than those for Peerless iron, a common medium used in PRBs. In addition, the TOC and clay in foundry sands can significantly retard the movement of target contaminant, which may result in lower effluent concentration of contaminant due to biodegradation. In general, PRBs 1-m thick can be constructed with many foundry sands to treat TCE provided the zero-valent iron content in the foundry sand is higher than 1%.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.542-547
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• 2000

It has become interested in the concept of permeable barriers for the containment and/or destruction of contaminated groundwater. The purpose of these trench-like barriers is to provide in situ capture and possibly destruction of the contaminant while preserving groundwater flow to uncontaminated zones. For instance, a trichloreethylene(TCE) plume may be contained by a permeable in which reactive iron reduces TCE to ethylene and ethane, compounds which can be easily biodegraded. The objective of this research is to examine the feasibility of using zero-valent iron as a clean-up media in permeable reactive barrier system. A series of laboratory column tests are performed. The concentration of influent and effluent water and the rate of clean up are analysed from these test results. The experimental result shows that the majority of the contamination in groundwater is removed in the reactor. And it shows the corresponding increase in the concentration of chloride ions through the reactor. Results from this study indicate that permeable reactive barrier containing admixtures of zero-valent iron and other materials can effectively clean up groundwater contaminated with organic compounds.

• 한국지반공학회논문집
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• 제18권5호
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• pp.143-157
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• 2002

주물사의 일반적인 지하수 오염물질인 TCE에 대한 반응성을 조사하기 위해 batch와 column실험을 하였다. 본 실험에서 얻어진 주물사의 반응성은 실제 반응벽체에 쓰여지는 철에 비해 높거나 비슷한 결과를 나타내었다. 또한, 주물사에 포함된 클레이와 TOC에 의해 TCE의 이동이 급격히 감소하는 것을 관찰하였다. 따라서, 실제 현장 상황에서는 토양미생물에 의한 분해에 의해 계산된 값보다 훨씬 낮은 농도의 TCE가 검출되리라 예상된다. 실제 현장 반응벽체 설계에 있어서 1 m두께의 벽체가 설치되기 위해서는 주물사에 포함된 철의 함량이 1%이상이면 안전측으로 벽체설계가 가능하다고 볼 수 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1126-1131
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• 2006

This study is part of the project that develops the permeable preactive barrier to be applied in a landfill. The geotechnical applicability of the permeable preactive barrier that filters the leachate from the landfill was evaluated. Dry specimens were made using a mixture of sand, loess and bentonite. A series of experiments are performed to determine the unconfined compressive strength and permeability of various mixing ratio of bentonite, loess, and sand. The laboratory test indicate that the optimum-mixing ratio that satisfied the regulation of unconfined compressive strength(490kPa) and coefficient of permeability$(10^{-3}\sim10^{-4}cm/s)$ of the landfill was when the ratio of sand and loess was 8:2 with bentonite content of 2%. The permeable preactive barrier is different from an impermeable barrier in that it permits a limited diffusion of the leachate, which will be directly purified biologically and chemically in the landfill.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.250-253
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• 2002

Remediation of groundwater using zero valent iron filings has received considerable attention in recent years. However, zero valent iron is gradually transformed to iron(III) oxides at permeable reactive barriers, so the reduction of iron(III) oxides can enhance the longevity of the reactive barriers. In this study, microbial reduction of Fe(III) was performed in anaerobic condition. A medium contained nutrients similar to soil solution. The medium was autoclaved and deoxygenated by purging with 99.99% $N_2$ and pH was buffered to 6, while the temperature was regulated as 2$0^{\circ}C$. Activity of iron reducing bacteria were not affected by chlorinated organics but affected by iron(III) oxide. Although perchloroethylene(PCE) was not degraded with only ferric oxide, PCE was reduced to around 50% with ferric oxide and microorganism. It shows that reduced iron can dechlorinate PCE.

• 한국지반공학회지:지반
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• 제17권6호
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• pp.28-37
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• 2001

• Environmental Engineering Research
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• 제25권4호
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• pp.605-613
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• 2020

This study is to investigate the possibility of using activated carbon prepared from Iraqi date-pits (ADP) which are produced from palm trees (Phoenix dactylifera L.) as low-cost reactive material in the permeable reactive barrier (PRB) for treating lead (Pb⁺²) from the contaminated groundwater, and then compare the results experimentally with other common reactive materials such as commercial activated carbon (CAC), zeolite pellets (ZP). Factors influencing sorption such as contact time, initial pH of the solution, sorbent dosage, agitation speed, and initial lead concentration has been studied. Two isotherm models were used for the description of sorption data (Langmuir and Freundlich). The maximum lead sorption capacities were measured for ADP, CAC, and ZP and were found to be 24.5, 12.125, and 4.45 mg/g, respectively. The kinetic data were analyzed using various kinetic models particularly pseudo-first-order, pseudo-second-order, and intraparticle diffusion. COMSOL Multiphysics 3.5a depend on finite element procedure was applied to formulate transmit of lead (Pb⁺²) in the two-dimensional numerical (2D) model under an equilibrium condition. The numerical solution shows that the contaminant plume is hindered by PRB.

• Geomechanics and Engineering
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• 제31권3호
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• pp.305-318
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• 2022

Permeable reactive barriers used for groundwater treatment require proper estimation of the reactive material behavior regarding the emplacement method. This study evaluates the dry emplacement of zeolite (clinoptilolite) to be used as a reactive material in the barrier by carrying out several geotechnical laboratory tests. Dry zeolite samples, exhibited higher wetting-induced compression strains at the higher vertical stresses, up to 12% at 400 kN/m². The swelling potential was observed to be limited with a 3.5 swell index and less than 1% free swelling strain. Direct shear tests revealed that inundation reduces the shear strength of a dry zeolite column by a maximum of 10%. Falling head permeability tests indicate decreasing permeability values with increasing the vertical effective stress. Regarding self-loading and inundation, the porosity along the zeolite column was calculated using a proposed 1D numerical model to predict the permeability with depth considering the laboratory tests. The calculated discharge efficiency was significantly decreased with depth and less than 2% relative to the top for barrier depths deeper than 20 m. Finally, the importance of directional dependence in the permeability of the zeolite medium for calibrating 2D finite element flow analysis was highlighted by bench-scale tests performed under 2D flow conditions.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.73-76
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• 2004

Rusted iron could retain activity to redox-sensitive pollutants in batch reactor. Flow-through columns packed with permeable reactive iron filings (Fe$^{0}$ ) between soil and sand layers were used to evaluate the applicability of bio-enhanced iron barriers to treat explosives-contaminated groundwater. One column was bioaugmented with municipal anaerobic sludge to evaluate the enhancement of biodegradation. Military contaminants (RDX, HMX, TNT, 2,4DNT, 2,6DNT), which coexist in soils at military sites, were completely removed in the bioaugmented Fe$^{0}$ layer after 8 months of operation. Overall, this research suggests that Fe$^{0}$ barriers can effectively clean up groundwater contaminated with military explosives, and that treatment efficiency can be enhanced by bioaugmentation.

• 한국지반공학회논문집
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• 제18권5호
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• pp.159-167
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• 2002

아연의 주물사에 대한 분배계수는 주물사에 포함된 TOC, 점토 함량, 총 철 함량 등에 따라 변하고 특히 용액 PH에 큰 영향을 받는 것을 관찰하였다. Batch 실험으로부터 얻어진 경험식으로부터분배계수와 제거상수를 예측할 수 있었다. Batch kinetic 실험과 batch sorption 실험으로부터 얻어진 분배계수는 용액 pH가 같을 시 거의 같은 값을 보이고 있다.