• Wind and Structures
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• 제3권1호
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• pp.11-21
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• 2000

This paper presents results of modeling of the passive contaminant diffusion from a continuous line finite-size source located on the underlying surface of a neutral near-ground atmospheric layer obtained by using the non-local two-parameteric turbulence model and the transport equation of mean concentration. In the proposed diffusion model the turbulent diffusion coefficient changes not only with the vertical coordinate but also with the distance downstream from the source according to the experimental data. The results of the modeling reproduce structural features of the concentration field.

• Environmental Engineering Research
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• 제12권4호
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• pp.176-193
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• 2007

The ability to measure groundwater contaminant flux is increasingly being recognized as crucial in order to prioritize contaminated site cleanups, estimate the efficiency of remediation technologies, measure rates of natural attenuation, and apply proper source terms to model groundwater contaminant transport. Recently, a number of methods have been developed and subsequently applied to measure contaminant mass flux in groundwater in the field. Flux measurement methods can be categorized as either point methods or integral methods. As the name suggests, point methods measure flux at a specific point or points in the subsurface. To increase confidence in the accuracy of the measurement, it is necessary to increase the number of points (and therefore, the cost) of the sampling network. Integral methods avoid this disadvantage by using pumping wells to interrogate large volumes of the subsurface. Unfortunately, integral methods are expensive because they require that large volumes of contaminated water be extracted and managed. Recent work has investigated the development of an integral method that does not require extraction of contaminated water from the subsurface. We begin with a review of the significance and importance of measuring groundwater contaminant mass flux. We then review groundwater contaminant flux measurement methods that are either currently in use or under development. Finally, we conclude with a qualitative comparison of the various flux measurement methods.

• 한국토양환경학회지
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• 제4권1호
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• pp.69-73
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• 1999

PCAPS는 토양 간극수를 효율적으로 포집하기 위해서 fiberglass wick의 모세관 잠재력을 이용하여 토양오염을 조사하는 장치이다. Fiberglass에 붙어 있는 불순물은 wick의 모세관 성질과 포집된 시료의 화학적 성질에 영향을 미치게 되므로 4가지 처리방법들 (소각처리, 아세톤처리, 세정제처리, 비세척)을 이용하여 불순물을 제거하였다. Wick은 미국의 PPG Industries와 Manville Company에서 생산되는 제품을 사용하였다. 실험결과로, PPG fiber는 소각처리에 의해 원래 부피의 3.4%정도 손실되었으며, Manville fiber 는 0.6%미만이 손실되었다. 이들 손실은 제작과정에 사용된 유기합성물이 소각되면서 발생하였다. 모든 세척방법들은 비세척 방법보다 모세관의 상승높이가 더 크게 나타났다. 소각이 가장 좋은 세척방법으로 나타났으며 40$0^{\circ}C$의 온도에서 4시간 처리시 불순물의 98~100%를 제거할 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권2_spc호
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• pp.28-54
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• 2020

Even though a systematic sampling approach is very crucial in both the general and detailed investigation phases to produce the best conceptual site model for contaminated sites, the concept is not yet established in South Korea. The U.S. Environmental Protection Agency (EPA) issued the 'Strategic Sampling Approaches Technical guide' in 2018 to help environmental professionals choose which sampling approaches may be needed and most effective for given site conditions. The EPA guide broadly defines strategic sampling as the application of focused data collection across targeted areas of the conceptual site model (CSM) to provide the appropriate amount and type of information needed for decision-making. These strategic sampling approaches can prevent the essential data from missing, minimize the uncertainty of projects and secure the data which are necessary for the important site-decisions. Furthermore, these provide collaborative data sets through the life cycle phases of projects, which can generate more positive proofs on the site-decisions. The strategic sampling approaches can be divided by site conditions. This technical guide categorized it into eight conditions; High-resolution site characterization in unconsolidated environments, High-resolution site characterization in fractured sedimentary rock environments, Incremental sampling, Contaminant source definition, Passive groundwater sampling, Passive sampling for surface water and sediment, Groundwater to surface water interaction, and Vapor intrusion. This commentary paper introduces specific sampling methods based on site conditions when the strategic sampling approaches are applied.

• 설비공학논문집
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• 제23권2호
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• pp.153-163
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• 2011

Energy efficiency and indoor air quality have become main issue to develop healthy and sustainable building in these days. As an effort to reduce the energy consumption in multi-residential building, many attempts as like passive design strategies and renewable energy as well as active control method are tried. However, underground parking lot in multi-residential building seldom adopt the sustainable strategies and only mechanical system is installed as usual. Moreover, the mechanical system installed in underground parking lot is rarely operated due to the electric demand for operation after completion. In this study, as an energy efficient measure, natural ventilation system using stack effect as a driving force for underground parking lot will be proposed and the performance of the suggested system will be analyzed by simulation method.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 정기총회 및 춘계 공동 학술발표회
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• pp.149-156
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• 1999

In the United States (U.S.), the monitored natural attenuation (MNA) approach has been used as an alternative remedial option for organic and inorganic compounds retained in soil and dissolved in groundwater. The U.S. Environmental Protection Agency (EPA) defines the MNA as“in-situ naturally-occurring processes include biodegradation, diffusion, dilution, sorption, volatilization, and/or chemical and biochemical stabilization of contaminants and reduce contaminant toxicity, mobility or volume to the levels that are protective of human health and the environment”. The Department of Soil Environment. National Institute Environmental Research (NIER) is in the process for demonstrating the MNA approach as a potential remedial option for the BTEX contaminated site in Uiwang City. The project is charactering the research site in terms of the nature and extend of contamination, biological degradation rate, and geochemical and hydrological properties. The microbial-degradation rate and effectiveness of nutrient and redox supplements will be determined through laboratory batch and column tests. The geochemical process will be monitored for determining the concentration changes of chemical species involved in the electron transfer processes that include methanogenesis, sulfate and iron reduction, denitrification, and aerobic respiration. Through field works, critical soil and hydrogeologic parameters will be acquired to simulate the effects of dispersion, advection, sorption, and biodegradation on the fate and transport of the dissolved-phase BTEX plume using Bioplume III model. The objectives of this multi-years research project are (1) to evaluate the MNA approach using the BTEX contaminated site in Uiwang City, (2) to establish a standard protocol for future application of the approach, (3) to investigate applicability of the passive approach as a secondary treatment remedy after active treatments. In this presentation, the overall picture and philosophy behind the MNA approach will be reviewed. Detailed discussions of the site characterization/monitoring plans and risk-based decision-making processes for the demonstration site will be included.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.37-44
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• 2003

MTBE(Methyl tertiary Butyl Ether)와 같은 가솔린 연료의 첨가제의 사용은 대기오염물질의 발생을 효과적으로 감소시키지만, 다른 한편으로는 지하저장 시설로부터의 누출로 인해 토양 및 지하수의 오염을 유발할 수 있다. 특히 MTBE는 높은 용해성으로 인해 지하수내에서는 지하수와 함께 광범위하게 오염을 유발할 수 있다. 본 연구에서는 MTBE를 대상 물질로 하여 폐타이어를 현장내 오염지하수 정화 공법 중 하나인 반응벽체 공법의 흡착매질로 사용을 평가하기 위해, 회분식 실험을 통해서 크기가 다른 폐타이어의 MTBE흡착 특성을 파악해 보았다. 또한 칼럼 실험을 통해서 이용 효율(Utilization Efficiency)을 구하였다. 1.18mm 이하의 폐타이어의 g당 최대 흡착량은 약 0.5 mg으로 나타났다. Freundlich 등온흡착식을 이용하여 구한 이론 흡착용량과 실제 평균 농도 측정을 한 후 계산된 MTBE의 흡착량을 비교하여 이용 효율을 계산 해본 결과, 지름이 가장 작은 폐타이어가 약 36%,나머지 두 가지 종류의 폐타이어는 각각 15.6%와 16.4%의 효율을 나타내었다. 폐타이어의 처분비용과 재생비용을 고려한다면, 폐타이어의 이용은 경제적, 환경적 측면에서 유익하리라 생각되며, 또한 Air-Sparging이나 Bioremediation과 같은 다른 현장내 공법과 복합적으로 적용된다면, 제거효율 향상과 같은 동반 상승효과(synergy effect)를 기대할 수 있을 것이라 사료된다.