Introduction to Smart Subsurface Environment Management Research Center

( Ho Young Jo ),( Man Jae Kwon ),( Myung Jin Nam ),( Jehyun Shin ),( Weon Shik Han ),( Seung-hak Lee ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

As the development and use of the underground space is increasing, the subsurface contamination is widening, the contamination continues for a long period of time, and the depth of contamination is gradually deepened, which can lead to enormous socio-economic costs in the future. Realistic characterization of the subsurface contamination is difficult due to the heterogeneities in the subsurface, which control distribution, transport, and fate of contaminants. Understanding the subsurface heterogeneities on the various scales is essential for evaluating and remediating contaminated sites. In 2018, the Ministry of Environment, South Korea launched 'Subsurface Environment Management (SEM) Project' to implement sustainable subsurface environment management. The 'smart Subsurface Environment Management Research Center (smart SEM research center)' was launched in June 2018 as part of the SEM project by the Ministry of Environment, South Korea. The aims of the smart SEM research center are to develop integrated technologies for diagnosing, evaluating, and predicting pathways and distributions of contaminants in the subsurface through multidisciplinary research. Main tasks for the SEM research center are; (1) the evaluation of field and laboratory technologies for diagnosing and investigating contaminant pathways and distribution in the subsurface, (2) characterization of contaminant pathways and distribution in the subsurface using surface and borehole geophysical exploration techniques, (3) three-dimensional visualization of contaminant pathways and distribution in the subsurface, and (4) prediction of contaminant transport and fate in the subsurface. These activities will contribute to the development of realistic conceptual site models for contaminated sites, helping to remediate and manage the contaminated sites.

점도변화에 따른 바닥 오염물질의 미끄러짐 저항 특성

박재석 ( Jae Suk Park ),오환섭 ( Whan Sup Oh ) 한국안전학회(구 한국산업안전학회) 2012 한국안전학회지 Vol.27 No.5

While there is no standards on slip risk for contaminants on surface, glycerol is described in standard contaminant for measuring coefficient of friction (COF) and slip resistance such as ISO 13287, But that is just used to measure the slip resistance of surface materials and shoes not to evaluate the contaminant materials, Therefore the objective of this study was to find out the relationship between standard contaminant and the contaminants used usually at the workplaces. For this, some measurement criteria were acquired from the analysis based on biomechanics and kinetics of human gait during slips. The slip resistance according to viscosity of the contaminants was measured applying the criteria and slip probability was determined by the gait analysis. Some factors which should be considered when measuring the slip resistance were identified. The velocity, acceleration, contact time and contact pressure should be 1 m/sec, 10 m/sec2, 350kPa and less than 0.5sec respectively. The variation of viscosity according to temperature for working oils was different from that of standard contaminant. The static coefficient of friction (SCOF) of working oils was almost 0.5 times as large as the SCOF of standard contaminant. So it was assumed to be difficult to compare the contaminants at the workplaces with the glycerol as a standard contaminant for estimating the slip risk.

범용 시나리오 및 오염물질 시나리오에 기반한 불포화대 오염물질 경로에 대한 수치모의 연구

장선우,김민규,정일문 대한토목학회 2019 대한토목학회논문집 Vol.39 No.6

This study tested various assumptions that simplified the configuration of the numerical model for unsaturated zone’s contaminant transport to simulate the pathway to exposed point. This study investigated the contaminant migration through in the pollutant exposure pathway of vadoze zone for risk assessment of the contaminated site. For the purpose, generic scenarios as well as contaminant-based scenarios were simulated using the numerical code for transport of the contaminant in the pathway. The finite-difference one-dimensional transport with adsorption and biodegradation were considered, and it also assumed that the initialconcentration was also depleted over time. The results of the generic-scenario show that as the groundwater infiltration rate decreases, the longer the path from the source to the groundwater level, the lower the concentration at the point of inflow into the groundwaterlevel. In particular, in the case of high biodegradation rate and rapid depletion of pollutant sources, statistically outliers were found in the simulated results and generic scenarios was good at prediction. 본 연구는 오염부지의 위해성 평가를 위해 수치모의 기반 오염물질의 노출이동경로 평가에 활용가능한 개념모델을 제시하였다. 이를 위하여 1차원으로 유한차분 기법을 적용하여 지하수 내 오염물질 이송확산을 모의하였다. 불포화대 경로에서의 수리지질학적 및 오염물질 매개변수가 가질 수 있는 범위를 설정하여 범용 시나리오 및 오염물질별 시나리오를 구성하여 모의에 적용하였다. 모델에서는 흡착 및 생분해를 갖는 유한차분 1 차원 이송확산이 고려되었고, 또한 초기 농도가 시간이 지남에 따라 고갈되는 것을 가정하였다. 일반 시나리오의 결과는 지하수 침투율이감소함에 따라, 오염원에서 지하수면까지의 경로가 길어질수록 지하수면으로 유입되는 지점의 농도 범위는 낮아졌다. 특히, 높은 생분해 속도와 오염원의 빠른 고갈의 경우, 범용 시나리오가 좁은 범위의 지하수 유입농도 예측치를 보여주었다.

토양지하수 미세환경과 오염정화효율과의 상관성 고찰

심무준,양중석,이미정,이기현,박재선,김국진,민상윤,김주영,최민주,김민찬,임종환,권만재,Shim, Moo Joon,Yang, Jung-Seok,Lee, Mi Jung,Lee, Giehyeon,Park, Jae Seon,Kim, Guk Jin,Min, Sang Yoon,Kim, Joo Young,Choi, Min Joo,Kim, Min Chan,Lim, Jon 한국지하수토양환경학회 2014 지하수토양환경 Vol.19 No.1

산업화의 영향으로 발생한 토양 지하수 내 중금속 및 유류 오염정화를 위해 다양한 시도가 이루어지고 있다. 그러나 미세토양이 상대적으로 많이 포함되어 있는 오염토양 정화시 오염물질의 rebound나 tailing 현상이 발생되어 정화기간이 장기화 되어왔다. 이러한 문제점은 미세토양과 미세공극이 존재하는 미세환경과 오염물질의 각각의 특성, 존재형태, 그리고 상호간의 다양한 반응 등으로부터 기인한다고 보고되었다. 따라서, 본 연구에서는 토양 지하수 미세환경과 오염정화 효율성과의 상관성에 대해 고찰하고 미세환경의 샘플링, 분석, 평가 기법을 소개 및 제안하며, 이를 활용한 오염정화효율 향상과 최적의 정화공법선정을 위한 정보를 제공하고자 하였다. 오염토양의 물리 화학 생물학적 특성 그리고 오염물질 종류 및 특성에 따른 정밀 평가를 통해 특정 정화공법 적용시 달성 가능한 정화기간과 정화수준을 예상할 수 있을 것이다. 따라서, 미세환경의 정밀 분석, 평가 기술을 바탕으로 정화 기술의 효율성과 타당성 검토가 가능할 것으로 판단되며 오염된 토양 지하수 복원을 위한 최적의 정화공법을 선정하는 기초자료로써 활용될 수 있을 것으로 사료된다. A variety of physical, chemical, and microbiological techniques have been developed to deal with soil and groundwater contamination. However, in the presence of the large portion of soil micro-environments, contaminant rebound and/or tailing have been frequently reported. Case study of total petroleum hydrocarbons (TPH) removal by full-scale land farming showed that contaminant rebound and/or tailing occurred in 9 out of total 21 cases and subsequently resulted in problems of a long term operation to satisfy TPH guidelines of contaminated soil and groundwater. The main cause of contaminant rebound and tailing is considered to be the strong interactions between contaminants and micro-environments including micro-particles, micro-pores, and organic matter. Thus, this study reviewed the effects of soil micro-environments of soil and groundwater on the removal efficiency for both heavy metals and petroleum contaminants. In addition, the various methods of sampling, analysis, and assessment of soil micro-environments were evaluated. Thorough understanding of the effects of soil micro-environments on contaminant removal will be essential to achieve a cost-effective and efficient solution to contaminated sites.

A Study on the Impact of Animal Intrusion Into Near-Surface Disposal Facility for LLW Radioactive Waste

Hyun Woo Song,Moonoh Kim,Hyosub Kim,Sang June Park,Suil Bang 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Near-surface disposal facility is more susceptible to intrusion than underground repository, resulting in more possible pathways for contaminant release. Alike human intrusion, animals (e.g. Ants, Moles, etc.) could intrude into the disposal site to excavate burrows, which could cause direct release of contaminants to biosphere. In this paper, animal intrusion is demonstrated using GoldSim’s commercial contaminant transport module and impact on the integrity of the near-surface disposal facility is evaluated in terms of fractional release rate of the contaminants. In this study, the near-surface disposal facility is modelled with a single concrete vault to contain radionuclide according to LLW concentration limit stated in NSSC notice No.2020-6. The release of contaminants is modelled to occur directly after the institutional control period, and the contaminants are mostly transported from the concrete vault to cover layers via diffusion. To produce mathematical model of the release of the contaminants due to animal intrusion, firstly, the fraction of burrow volume for each cover layer is calculated separately for each animal species, based on their maximum possible intrusion depth. In this study, fractions of burrow volume for ants and moles are calculated based on their maximum possible intrusion depths, where for ants is 2–3 m, and for moles is 0.1–0.135 m. Then, assuming that the contaminants are distributed homogeneously throughout each cover layers by diffusion, fraction of contaminants transported into the uppermost layer via excavation of the burrow is calculated for each layer based on burrow volume, and fraction of contaminants removed from the uppermost layer to the layers below via collapse of the burrow is also calculated based on the burrow volume. Lastly, the net transportation of contaminants into and out of the burrow via excavation and collapse, respectively, is calculated and demonstrated using direct transfer rate function of the GoldSim. Based on the simulated result, the maximum mass flux is too minor to cause a meaningful impact on the safety. The peak mass flux of the most sensitive radionuclide, I-129, is witnessed at around year 1,470, with a flux value of 5.36×10?6 g·yr?1. This minor release of the contaminants could be due to cover layers being much thicker than the maximum possible intrusion depth of the animals, preventing the animal intrusion into the deeper layers of higher radionuclide concentration. In future, this study can be used to provide a guidance and fundamental data for scenario development and safety evaluation of the near-surface disposal facility.

Hydrogeological Study on Contaminant Transport with Optimization Technique

( Yu-chul Park ),( Ho-jin Jeong ),( Hyun-soo Jeon ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

Contaminant transport has been known as one of the most difficult problems because of aquifer heterogeneity and complicated physical, chemical and biological reactions of contaminants. It could be more difficult jobs to estimate remediation time and costs where groundwater was contaminated with organic solvents in industrial complexes. This study showed how to use optimization techniques for estimating contaminant transport and remediation time and costs. Groundwater flow was modeled with MODFLOW and contaminant transport was modeled with MT3D and RT3D. The initial location and concentration were estimated with optimization techniques such as Genetic Algorithm. Parallelization technique was used to reduce computation time and costs. This research project is funded by the Ministry of Land, Transport and Maritime Affairs and supported by the National Institute of Land, Infrastructure and Transport Technology (Project number: 17TBIP-C125148-01). This research was also supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education (No.2019R1A6A1A03033167).

Contaminant transport through porous media: An overview of experimental and numerical studies

Patil, S.B.,Chore, H.S. Techno-Press 2014 Advances in environmental research Vol.3 No.1

The groundwater has been a major source of water supply throughout the ages. Around 50% of the rural as well as urban population in the developing countries like India depends on groundwater for drinking. The groundwater is also an important source in the agriculture and industrial sector. In many parts of the world, groundwater resources are under increasing threat from growing demands, wasteful use and contamination. A good planning and management practices are needed to face this challenge. A key to the management of groundwater is the ability to model the movement of fluids and contaminants in the subsurface environment. It is obvious that the contaminant source activities cannot be completely eliminated and perhaps our water bodies will continue to serve as receptors of vast quantities of waste. In such a scenario, the goal of water quality protection efforts must necessarily be the control and management of these sources to ensure that released pollutants will be sufficiently attenuated within the region of interest and the quality of water at points of withdrawal is not impaired. In order to understand the behaviour of contaminant transport through different types of media, several researchers are carrying out experimental investigations through laboratory and field studies. Many of them are working on the analytical and numerical studies to simulate the movement of contaminants in soil and groundwater of the contaminant transport. With the advent of high power computers especially, a numerical modelling has gained popularity and is indeed of particular relevance in this regard. This paper provides the state of the art of contaminant transport and reviews the allied research works carried out through experimental investigation or using the analytical solution and numerical method. The review involves the investigation in respect of both, saturated and unsaturated, porous media.

천연기념물 진주 충무공동 익룡·새·공룡발자국 화석산지의 오염물 형성 메커니즘과 관리방안

최명주(Myoungju Choie),원상호(Sangho Won),이태종(Tea Jong Lee),이성주(Seong-Joo Lee),공달용(Dal-Yong Kong),이명성(Myeong Seong Lee) 대한자원환경지질학회 2023 자원환경지질 Vol.56 No.6

익룡 발자국의 개체 및 밀집도 측면에서 세계 최대 규모로 알려진 진주 충무공동 익룡·새·공룡발자국 화석산지는 2011년 천연기념물로 지정된 이래, 2018년 일부 화석층을 현장 보존하기 위해 보호각을 설치하였다. 이 중 제2보호각에 관리중인 화석층은 기 보고된 발자국 중 약 17%에 달하는 익룡·수각류·조각류 발자국(총 679개)이 단일 층준에서 발견되어 학술적 가치가 크지만 물리적, 화학적 손상이 지속적으로 발생하여 발자국의 관찰에 어려움이 있다. 특히 화석층 표면을 피복하는 유백색 오염물은 석고와 대기오염물로 구성된 복합체의 누적현상에서 기인한다. 오염물을 구성하는 석고는 화석층 하부층준에서 기원한 칼슘과 잔디의 생육활동으로 공급되는 황이 보호각 후방의 잔디가 식재된 토양층에서 집수된 지하수에 의해 용출되고, 보호각의 일대의 수분 순환 과정에서 화석층 표면에 증발잔류하며 결정화된다. 또 다른 오염물 구성체인 화분·광물 등은 분진 배출이 어려운 보호각 갤러리창을 통해 풍성으로 유입된다. 따라서 상이한 기원을 가진 두 오염물로부터 화석층을 보존하기 위해서는 보호각의 수분 및 대기 순환 제어와 지속적인 오염물 제거가 필요하다. 분진상의 석고와 대기 오염물은 스팀 세정법으로 충분한 제거 효과가 있으며, 암회색 셰일인 화석층은 레이저 흡수능이 커 흔적화석과 퇴적구조의 물리적 손실을 동반하는 레이저 세정법은 가급적 지양하는 것이 바람직하다. Tracksite of pterosaurs, birds, and dinosaurs in Chungmugong-dong in Jinju was designated as a natural monument in 2011 and is known as the world's largest in terms of the number and density of pterosaur footprints. This site has been managed by installing protection buildings to conserve in 2018. About 17% of the footprints of pterosaur, theropod, and ornithopod in this site under management in the 2nd protection building are of great academic value, but observation of footprints has difficulties due to continuous physical and chemical damage. In particular, the accumulation of milk-white contaminants is formed by the gypsum and air pollutant complex. Gypsum remains evaporated with a plate or columnar shape in the process of water circulation around the 2nd protection building, and the dust is from through the inflow of the gallery windows. The aqueous solution of gypsum, consisting of calcium from the lower bed and sulfur from grass growth, is catchmented into the groundwater from the area behind the protection building. Pollen and a few minerals other constituents of contaminants, go through the gallery window, which makes it difficult to expel dust. To conserve the fossil-bearing beds from two contaminants of different origins, controlling the water and atmospheric circulation of the 2nd protection building and removing the contaminants continuously is necessary. When cleaning contaminants, the steam cleaning method is sufficiently effective for powder-shaped milk-white contaminants. The fossil-bearing bed consists of dark gray shale with high laser absorption power; the laser cleaning method accompanies physical loss to fossils and sedimentary structures; therefore, avoiding it as much as possible is desirable.

조위변화를고려한 해상처분장 2열 연직차수공에서의 오염물질 이동특성 평가

채광석(Kwangseok Chae),오명학(Myounghak Oh) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.3

Vertical hydraulic barrier is essential component to prevent leachate leakage in offshore containment facilities. Double steel pipe sheet pile is one of effectively used as vertical hydraulic barrier in Japanese offshore waste landfill sites. In this study, two-dimensional finite element analysis was performed to evaluate contaminant transport characteristics considering advection-dispersion-diffusion through double steel pipe sheet pile according to tidal fluctuation and different water level in landfill by using SEEP/W and CTRAN/W. Numerical analysis results indicate that water level in landfill should be maintain similar or lower compared with sea water level to prevent the leakage from landfill to sea. In addition, double steel pipe sheet pile was effective to prevent contaminant leakage to outside sea since filling zone between two barrier act as buffer zone for spreading contaminant.

격자 볼츠만 방법에 의한 지반 내 오염물질의 거동 분석

강동훈(Kang, Dong Hun),윤태섭(Yun, Tae Sup) 대한토목학회 2012 대한토목학회논문집 C Vol.32 No.6

오염물질의 거동은 간극 배열과 연결망에 의해 결정되지만 흙에서 오염물질의 이동을 계산하는 전통적인 접근은 거시 스케일에서 적용된다. 나비에-스토크스 방정식을 풀기 위해 소요되는 컴퓨팅 비용 때문에 간극 스케일에서 이동과 결과를 관찰하기 쉽지 않다. 본 논문에서는 단일상 다성분 유체유동에서 국부적인 유속과 밀도를 효과적으로 평가할 수 있는 격자 볼츠만 방법에 대해 설명한다. 오염물질의 시공간적 거동은 유체 유동의 이송에 의해 명시적으로 결정된다. 두 가지 형태의 이상화된 간극은 유체의 경로를 제공한다. 또한 오염물질 이동, 유속장, 오염물질의 평균 농도는 정상상태의 유통에서 계산된다. 굴곡비와 같은 간극 형상은 오염물질 거동의 영향을 준다. 이는 흙이나 암반의 불연속면에서 동일한 간극률를 가져도 간극의 배열과 형상의 중요함을 강조한다. The conventional approach to evaluate the contaminant transport in soils adopts the macro-scale implementation while the pore configuration and network is a dominant factor to determine the fate of contaminant. However, the observation of fate and transport at pore scale may not be readily approachable because of the computational expenses to solve Navier-Stokes equation. We herein present the 2D Lattice-Boltzmann method that enables to assess the local fluid velocity and density efficiently for the case of single phase and multi-components. The solute fate spatio-temperal space is explicitly determined by the advection of fluid flow. Two different types of idealized pore space provides the path of fluid. Also, solute transport, the velocity field and average concentration of solute are computed in steady state. Results show that the pore geometry such as tortuosity mainly affect the solute fate. It highlights the significance of the pore configuration and shape in granular soils and rock discontinuity in spite of the equivalent porosity.