• 대한자원환경지질학회:학술대회논문집
• /
• 대한자원환경지질학회 2005년도 춘계 학술발표회 논문집
• /
• pp.148-151
• /
• 2005

Field-scale DNAPL dissolution is controlled by the topology of DNAPL distributions with respect to the velocity field. A high resolution percolation model was developed and employed to simulate the distribution of DNAPL within source zones. Statistically anisotropic permeability values and capillary parameters were generated for 10${\times}$10${\times}$10 m domains at a resolution of 0.05 to 0.1 m for various statistical properties. TCE leakage was simulated at various rates and the distribution of residual DNAPL in 'fingers' and 'lenses' was computed. Variations in finger and lens geometries, frequencies, average DNAPL saturations, and overall source topology were predicted to be strongly influenced by statistical properties of the medium as well as by injection rate and fluid properties. Model results were found to be consistent with observations from controlled DNAPL release experiments reported in the literature. The computed distributions of aquifer properties and DNAPL were utilized to perform high-resolution numerical simulations of groundwater flow and dissolved transport. Simulations were performed to assess the effect of grout or foam injection in bore holes within the source zone and of shallow point-releases of fluids with various properties on dissolution in DNAPL dissolution rate, even for widely spaced injection points. The results indicate that measures that induced partial flow reductions through DNAPL source zones can significantly decrease dissolution rates from residual DNAPL. The benefit from induced partial flow reductions is two-fold: 1) local flow reduction in DNAPL contaminated zones reduces mass transfer rates, and 2) contaminant flux reductions occur due to the decrease in groundwater velocity

• Journal of applied mathematics & informatics
• /
• 제7권3호
• /
• pp.773-785
• /
• 2000

In this paper an algorithm is presented based on the additive Schwarz method for steady groundwater flow in a porous medium. The subproblems in the algorithm correspond to the problem on a coarse grid and some overlapping subdomains. It will be shown that the rate of convergence is independent of the mesh parameters and discontinuities of the coefficients, and depends on the overlap ratio.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.451-454
• /
• 2006

Fiber optic distributed temperature sensing and thermal line sensor are applied in an observation borehole and a loom deep borehole heat exchanger. For the case of permanently installed system fiber optic DTS is very useful. By comparing with TLS, fiber optic DTS shows good accuracy and reliability. Ground water flow can give influences at heat exchange rate of the heat pump system. According to the hydraulic characteristics and temperature-depth profile, we consider that temperature-depth profile do not seem to be dependent on ground water flow. A permanent installation of fiber optic cable is expected as a reliable temperature measurement technique in a borehole heat exchanger system.

• 분석과학
• /
• 제28권5호
• /
• pp.353-360
• /
• 2015

지하수 중 라돈은 끓임으로서 쉽게 제거할 수 있다. 다양한 라돈 농도를 가진 13 개 지하수 시료를 이용하여 가열 시간과 온도를 변경시키며 라돈의 제거효율을 평가하였다. 지하수 시료는 Bladder 펌프를 이용하여 채수하였고 용존산소, 수소이온농도 등의 현장수질은 Flow cell을 이용하여 측정 하였다. 경과시간 및 수온 별로 분취한 시료의 라돈 농도는 액체섬광계수기(LSC)로 분석하였다. 실험결과, 온도가 높을수록 경과시간에 따른 지하수 중 라돈의 제거율도 높아지며 지하수 중 라돈의 초기농도가 높을수록 경과시간에 따른 지하수 중 라돈의 제거율은 낮아진다. 즉, 지하수 중 라돈의 농도가 높을수록 가열에 의한 라돈 제거 시 더 많은 시간과 에너지를 필요로 한다. 따라서 지하수 중 라돈 제거율은 주로 라돈초기농도, 가열온도, 그리고 가열시간에 의해 결정된다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제15권4호
• /
• pp.1-12
• /
• 2010

Well production by a riverbank filtration facility with multi-radial collector well systems in Jeungsan-ri, Changnyeong gun, Korea was evaluated. In this study, the drawdown at collector wells due to pumping and groundwater inflow rates along the horizontal arms of the collector wells were computed through numerical simulations. Sensitivities of the well production to hydraulic conductivity and well flow coefficient, which represents the resistance to the flow from the aquifer to the horizontal arms, were analyzed. Simulation results showed that, with given proposed pumping rate conditions, the drawdown in the caisson exceeded maximum drawdown constraints in the study site and the adjustment of the pumping rate at each well is needed. The drawdown is affected by the hydraulic conductivity of the main aquifer and the well flow coefficient, which means the profound field investigation of the study site is needed to accurately estimate the efficiency of riverbank filtration through radial collector wells.

• 한국물환경학회지
• /
• 제28권5호
• /
• pp.743-753
• /
• 2012

The hydrologic models, capable of simulating groundwater recharge for long-term period and effects on it of crops management in the agricultural areas, have been used to compute groundwater recharge in the agricultural fields. Among these models, the Soil and Water Assessment Tool (SWAT) has been widely used because it could interpret hydrologic conditions for the long time considering effects of weather condition, land uses, and soil. However the SWAT model couldn't represent the spatial information of Hydrologic Response Unit (HRU), the SWAT HRU mapping module was developed in 2010. With this capability, it is possible to assume and analyze spatio-temporal groundwater recharge. In this study, groundwater recharge of rate for various crops in the Mandae stream watershed was estimated using SWAT HRU Mapping module, which can simulate spato-temporal recharge rate. As a result of this study, Coefficient of determination ($R^2$) and Nash-Sutcliffe model efficiency (NSE) for flow calibration were 0.80 and 0.72, respectively, and monthly groundwater recharge of Mandae watershed in Haean-myeon was 381.24 mm/year. It was 28% of total precipitation in 2009. Groundwater recharge rate was 73.54 mm/month and 73.58 mm/month for July and August 2009, which is approximately 18 times of groundwater recharge rate for December 2009. The groundwater recharges for each month through the year were varying. The groundwater recharge was smaller in the spring and winter seasons, relatively. So, it is necessary to enforce proper management of groundwater recharge during droughty season. Also, the SWAT HRU Mapping module could show the result of groundwater recharge as a GIS map and analyze spatio-temporal groundwater recharge. So, this method, proposed in this study, would be quite useful to make groundwater management plans at agriculture-dominant watershed.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
• /
• pp.137-140
• /
• 2000

The purpose of this study is to see the effect of SVE (Soil Vapor Extraction) and Bioventing (biostimulation) hydrocarbon contaminated areas. The removal rate of VOC for three weeks were 17.43 kg on 3.6 ㎥/hr at steady-state. In the application of Bioventing, every flow rate were tested, and it was found that 4.0 ㎥/hr were adequate for best control of the system. At this stage, the addition of microbial agent accelerated the biodegradation of the hydrocarbon.

• 대한토목학회논문집
• /
• 제38권4호
• /
• pp.517-526
• /
• 2018

지하수 함양은 기후조건, 토지이용, 수리지질학적 비균질성에 의해 시공간적인 변동성을 나타내므로 통합수문해석에 의한 지하수 함양량의 추정이 필요하다. 본 연구에서는 SWAT-MODFLOW 연계모형을 활용하여 장성지역의 물리적 기반의 일단위 지하수 함양량을 산정하였다. 수문분석은 하천에서의 관측유량과 계산유량의 검보정에 이어 부정류 지하수위의 계산값과 관측값의 비교를 통해 모형의 정확도를 평가하였다. 추정된 수문성분은 상호간에 서로 관련이 깊고, 유역내의 비균질한 인자들인 소유역 경사, 토지이용, 토양종류에 따라 지하수 함양량의 공간적 변동이 크게 나타났다. 통합수문모형은 지표수 및 지하수 수문성분 프로세스의 시공간적 변화를 잘 모의하고 있는 것으로 평가되었다. 추정된 함양량의 평균은 약 20.8%로 나타났다.

• 한국지열·수열에너지학회논문집
• /
• 제9권3호
• /
• pp.1-10
• /
• 2013

Open loop geothermal heat pumps have great potential where the groundwater resources are sufficient. Performance of open loop geothermal heat pump systems is considered higher than that of ground source heat pumps. Head and power calculation of submersible pumps, heat pump units, and piping are numerically based on regression data. Results shows that the system performance drops as the water level drops, and the lowest flow rates generally achieve the highest system COPs. The highest achievable cooling system COPs become 6.34, 6.12, and 5.95 as the groundwater levels are 5m, 15m, and 25m. The highest heating system COPs also become 4.59, 4.37, and 4.20. Groundwater level and submersible pump selection greatly influence the system performance of open loop geothermal heat pumps. It needs to be analysed during the design process of open loop geothermal heat pump system, possibly with analysis tools that include wide range of pump product data.

• 한국방재학회 논문집
• /
• 제8권1호
• /
• pp.145-151
• /
• 2008

농어촌지역의 하수종말처리시설 민간투자사업에 대한 계획인구 및 계획하수량 산정 방법을 검토하였다. 기존의 추정 방법에서는 인구 감소 추세임에도 불구하고, 인구가 정체될 것으로 가정하여 계획인구를 추정하고 있으며, 수도보급률이 매우 낮은 지역에서의 계획하수량을 정수장 급수보급량을 이용하여 산정하고 있다. 결과적으로 계획 인구 및 계획하수량의 과다 산정은 필요이상의 하수종말처리시설이 만들어지게 되는 결과를 가져오게 된다. 그러므로 본 연구에서는 계획 인구는 통계청의 장래인구 추계결과를 따르는 것으로 하고, 수도가 보급된 지역에서는 급수사용량을, 수도가 보급되지 않은 지역에서는 지하수 사용량을 이용하여 계획하수량을 산정하는 방안을 제시하였다.