• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.119-125
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• 2014

This study evaluated the environmental impacts of a soil washing (SW) process, especially, we compared the on-site and off-site remediation of TPH-contaminated soil using green and sustainable remediation (GSR) tool. To assess relative contribution of each stage on environmental footprints in the entire soil washing process, we classified the process into four major stages: site foundation (stage I), excavation (stage II), separation & washing (stage III), and wastewater treatment (stage IV). In on-site SW process, the relative contribution of $CO_2$ emissions and energy consumption were 87.1% and 80.4%, respectively in stage I, and in off-site SW process, the relative contribution of $CO_2$ emissions and energy consumption were 82.7% and 80.5%, respectively in stage II. In conclusion, the major factor contributing environmental impact in the SW process were consumable materials including steel and stainless steel for washing equipment in on-site treatment and fuel consumption for transportation of soil in off-site treatment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.213-226
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• 2019

Regulatory agency and licensee are preparing for the site restoration of Kori unit 1, the first commercial NPP in Korea, scheduled for 2031. Developing regulatory guidelines and strategies is essential for effective restoration work. Unfortunately, Korea does not have experience of site restoration of commercial NPPs. Therefore, it is important to review cases from experienced countries to establish a strategy and regulatory standards. The U.S. has had numerous soil remediation experiences using RESRAD and MARSSIM. However, formalized evaluation methodologies for subsurface soil have not yet been established in MARSSIM. This survey focused on subsurface soil remediation by reviewing the five decommissioned NPPs under regulation of the US NRC. Overall process of remediating a contaminated subsurface soil and groundwater was reviewed to identify considerations and lessons that could be applicable in Korea. In addition, an applied methodology for evaluation of contaminated subsurface soil and related major issues between regulatory agency and licensees were reviewed in detail to support establishment of remediation strategy for Kori unit 1.

• Environmental Engineering Research
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• v.12 no.4
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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.

• Economic and Environmental Geology
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• v.32 no.1
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• pp.73-82
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• 1999

The objectives of this study are to investigate soil contamination in the vicinity of abandoned Au-Ag mine and to apply a remediation technique of liming to tailings. In the study area of the Imcheon Au-Ag mine, soils were sampled in and around the mine the analyzed by Atomic Absorption Spectrometry extracted by both 0.1N HCl and aqua regia. Elevated levels of Cd, Cu, Pb and Zn concentrations extracted by 0.1N HCl were found in soils taken from tailings site. These high contents directly influenced metal concentrations in soils taken in the vicinity of the site. This is mainly due to clastic movement by wind and effluent of mine waste water. In addition, relatively enriched concentrations of the metals were found in soils extrated by aqua regia due to strong decomposition of the samples compared with 0.1N HCl extration. According to the statistical approach, metal concentrations in soils by 0.1N HCl had a positive correlation with those by aqua regia extraction. Mine waste waters and stream waters were also sampled around the mine in spring and summer and analyzed by AAS for Cd, Cu, Pb and Zn, and by Ion Chromatography for anions. Like soils developed over tailings, significant levels of metals and sulphates were found in the mine waste waters ranging of 0.2~0.3, 0.5~2.0, 0.2~2.8, 30~50 and 1,240~4,700 mg/l of Cd, Cu, Pb, Zn and $SO_4^{2-}$, respectively. These elevated levels influenced in the stream waters in the vicinity of the tailings site. In seasonal variation of metal and anion contents, relatively high levels were found in waters sampled on summer due to leaching the metals and anions from tailings by rain. This study also examined the possibility of lime treatment for remediation of acid mine tailings and assumed to be 46 tones of pulverized lime for neutralization of the tailings.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.52-61
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• 2014

Metal concentrations in the former Janghang smelter area were determined and human health risk of arsenic (As) with bioaccessibility was investigated. Site investigation of the area within 1.5 km from the Janghang smelter showed the As concentrations of 4.8~169.8 mg/kg (avg. 37.8 mg/kg). For 85 samples out of 126 samples, As concentrations were higher than the Worrisome Level of the Korean Soil and Environment Conservation Act, and seven samples exceeded the Countermeasure Standard. Risk assessment for As incorporated with the bioaccessibility revealed that potential human health risk of the carcinogenic ($1.8{\sim}5.0{\times}10^{-5}$) was above the acceptable risk range ($10^{-5}{\sim}10^{-6}$) while the risk of the non-carcinogenic was not found. Remediation goals based on risk incorporated with bioaccessibility of As ranged from 10.8 to 20.0 mg/kg. Such difference in the remediation goals resulted from various bioaccessibility of As (i.e., between 8.7~66.3%) at the study site.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.60-69
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• 1996

Along with rapid industrial development, toxic chemicals have been discharged extensively into the environment. Many of them have flowed into the soil which is final acceptor of environmental pollutants. As a result, they have deteriorated soil and groundwater environment. Once the soil and groundwater were contaminated by pollutants, these media can not be easily restored without artificial remediation. Foreign countries which accomplished earlier industrialization compared to our country have invested enormous capital for the remediation of contaminated sites and the development of relevant technology. In our country the reserch on the development of remediation technology has been conducted for several years, but it is still in its initial stage. This report represents remediation technologies, their adaptability and clean up procedure etc. which are being used for the managenent of contaminated site in advanced countries.

• Journal of Soil and Groundwater Environment
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• v.17 no.4
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• pp.44-50
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• 2012

A new type of chemical oxidation technology utilizing micro bubble ozone oxidizer and a pneumatic fracturing equipment was developed to enhance field applicability of a traditional chemical oxidation technology using hydrogen peroxide as an oxidizer for in-situ soil remediation. To find an efficient way to dissolve gaseous ozone into hydrogen peroxide, ozone was injected into water as micro bubble form then dissolved ozone concentration and its duration time were measured compared to those of simple aeration of gaseous ozone. As a result, dissolved ozone concentration in water increased by 31% (1.6 ppm ${\rightarrow}$ 2.1 ppm) and elapsed time for which maximum ozone concentration decreased by half lengthened from 9 min to 33 min. When the developed pneumatic fracturing technology was applied in sandy loam, cracks were developed and grown in soil for 5~30 seconds so that the radius of influence got longer by 71% from 392 cm to 671 cm. The remediation system using the micro bubble ozone oxidizer and the pneumatic fracturing equipment for field application was made and demonstrated its remediation efficiency at petroleum contaminated site. The system showed enhanced remediation capacity than the traditional chemical oxidation technology using hydrogen peroxide with reduced remediation time by about 33%.

• Journal of Environmental Impact Assessment
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• v.6 no.1
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• pp.93-103
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• 1997

LHR(Landfill Site Hazard Ranking Model) was developed for ranking the relative hazard of landfill sites by using the method of value-structured approach. LHR consists of combining a multiattribute decision-making method with a Qualitative risk assessment approach. A pairwise com parisian method was applied to determine weights of landfill site factors related. To determine the hazard of landfill site, hydrogeological factors, waste characteristics factors and receptors factors were evaluated by LHR. LHR can help decision-makers prioritization of remediation of landfill sites through the relatively convenient and concise evaluation method of landfill site features related. LHR focuses mainly on pathways of groundwater and surfacewater for evaluating landfill hazard to receptors including humans. To validiate the applicability of LHR, Nanjido Landfill site, Metropolitan Landfill site, and Hwasung Landfill site were evaluated.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.13-23
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• 2000

The effects of operating condition of soil vapor extraction system and the characteristics of site on the remediation of oil contaminated soil were investigated. Thorough investigation showed that the site was contaminated with gasoline leaked from underground storage tank and the maximum concentration of BTEX and TPH were 1,081 ppm and 5,548 ppm respectively. The leaked gasoline were diffused to 6m deep and the area and volume of the polluted soil were assumed to 170$m^2$ and 1,000$\textrm{m}^3$respectively. The site were consisted of three different vertitical layers, the top reclaimed sandy soil between the earth surface and 3~4m deep, middle silty sand between 3~4m and 6m deep, and the bottom bedrock below the 6m deep. The air pemeability of soil was measured to 1.058-1.077$\times$10$^{-6}$ $\textrm{mm}^2$ by vacuum pump tests. The groundwater which level was 3~4m deep was observed in some areas of this site. The soil vapor extraction system which had 7.5 HP vacuum pump and 8 extraction wells was constructed in this site and operated at 8 hrs/day for 100 days. The BTEX was removed with above 90% efficiency where no groundwater and silty sand were observed. On the contrary, the efficiency of BTEX and TPH were dramatically decreased where groundwater and silty sand were observed. The flow rate of soil air induced by soil vapor extraction system was reduced in deeper soil.

• Journal of Soil and Groundwater Environment
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• v.18 no.2
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• pp.36-44
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• 2013

The objectives of this study were to identify the characteristics of shallow groundwater from the oil-contaminated site for a long period and to evaluate the applicability of biopile technology to treat the soil excavated from it. The eight monitoring wells were installed in the contaminated site and pH, Electrical Conductivity (EC), Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), Temperature and the concentrations of major ions and pollutants were measured. The VOCs in soil gas were monitored during biopile operation and TPH concentration was analyzed at the termination of the experiment. The pH was 6.62 considered subacid and EC was 886.19 ${\mu}S/cm$. DO was measured to be 2.06 mg/L showing the similar characteristic of deep groundwater. ORP was 119.02 mV indicating oxidation state. The temperature of groundwater was measured to be $16.97^{\circ}C$. The piper diagram showed that groundwater was classified as Ca-$HCO_3$ type considered deep groundwater. The ground water concentration for TPH, Benzene, Toluene, Xylene of the first round was slightly higher than that of the second round. The concentration of carbon dioxide of soil gas was increased to 1.3% and the concentration of VOCs was completely eliminated after the 40 days. The TPH concentration showed 98% remediation efficiency after the 90 days biopile operation.