• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.48-56
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• 2017

Although various methods have been investigated for treatment of crude oil contaminated soil, more researches are still required to preserve soil environment. This study investigated the potential utility of subcritical water in remediation of crude oil contaminated soil under various experimental conditions including temperature ($150-300^{\circ}C$), flow rate (1.0-2.0 mL/min) and extraction time (60-120 min). The removal rate of crude oil gradually increased with increasing temperature and time. After treatment at $200^{\circ}C$ and $300^{\circ}C$ for 60 min, the remaining concentration of crude oil met the Kuwait standard clean-up level (10,000 mg/kg) and the Korean standard level (2,000 mg/kg), respectively. The removal efficiency of crude oil increased from 77.8% to 88.4% with increasing extraction time from 60 to 120 min at $250^{\circ}C$. A decreasing rate of oil removal was observed as flow rate increased, possibly due to channeling flow occurred within the soil body at higher flow rate condition. Overall, the results revealed that subcritical water extraction process could be feasible for remediation of crude oil contaminated soil, and the relative effect of parameters on the oil removal was in the order of temperature > time > flow rate.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.9-19
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• 2021

This study evaluated the feasibility of combined use of physical separation and soil washing to remediate heavy metals (Pb and Cu) contaminated soil in a military shooting range. The soils were classified into two types based on the level of heavy metal concentrations: a higher contaminated soil (HCS) with Pb and Cu concentrations of 6,243 mg/kg and 407 mg/kg, respectively, and a lower contaminated soil (LCS) with their concentrations of 1,658 mg/kg and 232 mg/kg. Pb level in both soils exceeded the regulatory limit (700 mg/kg), and its concentration generally increased with decreasing soil particle size. However, in some cases, Pb concentrations increased with increasing soil particle size, presumably due to the presence of residues of bullets in the soil matrix. As a pretreatment step, a shaking table was used for physical separation of soil to remove bullet residues while fractionating the contaminated soils into different sizes. The most effective separation and fractionation were achieved at vibration velocity of 296 rpm/min, the table slope of 7.0°, and the separating water flow rate of 23 L/min. The efficiency of ensuing soil washing process for LCS was maximized by using 0.5% HCl with the soil:washing solution mixing ratio of 1:3 for 1 hr treatment. On the contrary, HCS was most effectively remediated by using 1.0% HCl with the same soil:solution mixing ratio for 3 hr. This work demonstrated that the combined use of physical separation and soil washing could be a viable option to remediate soils highly contaminated with heavy metals.

• Journal of Soil and Groundwater Environment
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• v.25 no.4
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• pp.1-6
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• 2020

Recently, ex-situ remediation technologies has been emerging to clean up contaminated soils mainly because the in-situ techniques have limited applicability and technical difficulties in relatively small contaminated sites. Accordingly, implementation of off-site treatment and disposal have been continuously increased in soil remediation and restoration projects in Korea. However, in many cases, reclaimed soil is still not properly recycled or reused. Therefore, there is an urgent need to document the current status of soil management practices in soil remediation projects in the nation. This study presents a survey of soil contamination status and remedial approaches in Korea based on soil cleanup projects completed in 2015 - 2019, and proposes the possible options of the recycling or reusing the reclaimed soils under compliance with related regulations. The results of the soil survey showed soil contamination was most severe in gas stations, industrial facilities, and military areas. The major types of pollution were related to the petroleum-contaminated site (TPH and BTEX) with 77.0% occurrence in all the contaminated sites. The reclaimed soils were mostly reused as a ground filling-up soils in industrial facilities (60.0%) and warehouses (37.0%).

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.147-152
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• 2001

This study was carried out to investigate the effect of application time and amount of liquid pig manure on growth and yield of rice plant and infiltration water quality. Liquid manure treatment with higher application rate and closer application time to transplanting time showed higher plant height and number of tiller at panicle formation stage, but it caused the plant disease and pest and lodging. In liquid manure treatment with higher application rate, number of panicles per hill and number of spikelets per panicle were higher but yield of rice was less than chemical fertilizer treatment due to low rate of ripeness and 1,000 grain weight. $NO_3-N$ concentration in infiltration water sample was increased with increasing application amount of liquid manure and closer application time to transplanting of rice plant. With consideration yield of rice and environment such as groundwater quality, the proper application amount were 150% and 100% of recommending N fertilizer level (11kg) at before winter and April or May treatment, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.257-264
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• 2011

Recycling of industrial products as the stabilizers can be proper handling of industrial products and has positive side in terms of recycling of wastes. In this study, the final aims were to evaluate the usability as stabilizer of Bio-solids which was generated from contaminated soil with heavy metals after primary process and to compare the treatment efficiency with slag being currently applied in many existing sites. Soluble and exchangeable forms have closely related to pollution of groundwater and plant growth and they can be used to determine the effect of the stabilization efficiency. Slag and Bio-solids were tested to investigate the capacity of stabilizing arsenic. Slag treatment process 4 (PS-ball 5%) showed higher leachate concentration rather to 0.84% compared to treatment 1 (blank) based on an average of 0.63%. The other hand treatment 4 (Bio-solids 5%) showed the lowest soluble and exchangeable forms to 0.57% when Bio-solids was applied to stabilize arsenic. Thus, the leaching of arsenic will be more reduced if the Bio-solids are used as stabilizer in stead of slag which is being currently used in many fields.

• Journal of Soil and Groundwater Environment
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• v.14 no.5
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• pp.62-70
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• 2009

A field soil highly contaminated with petroleum hydrocarbons (JP-8 and diesel fuels) was employed for its remediation by a lab-scale thermal desorption process. The soil was collected in the vicinity of an underground storage tank in a closed military base and its contamination level was as high as 4,476 ppm as total petroleum hydrocarbon (TPH). A lab scale directly-heated low temperature thermal desorption (LTTD) system of 10-L capacity was developed and operated for the thermal treatment of TPH contaminated soils in this study. The desired operation temperature was found to be approximately $200-300^{\circ}C$ from the thermal gravimetric analysis of the contaminated field soils. The removal efficiencies higher than 90% were achieved by the LTTD treatment at $200^{\circ}C$ for 10 min as well as at $300^{\circ}C$ for 5 min. As the water content in the soils increased and therefore they were likely to be present as lumps, the removal efficiency noticeably decreased, indicating that a pre-treatment such as field drying should be required. The analysis of physical and chemical properties of soils before and after the LTTD treatment demonstrated that no significant changes occurred during the thermal treatment, supporting no needs for additional post-treatments for the soils treated by LTTD. The results presented in this study are expected to provide useful information for the field application and verification of LTTD for the highly contaminated geo-environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.827-831
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• 2008

In this study, the effects of reclaimed wastewater irrigation on the concentration of heavy metals such as lead, zinc, cadmium, and copper in soil and vegetables were investigated by monitoring an experimental area irrigated with reclaimed wastewater. Three treatments and three replications on $10{\times}2$-m plots were installed and heavy metal concentrations in soil and vegetables were monitored from 2005 to 2007. The treatments applied in this study were groundwater irrigation (control treatment), wastewater irrigation, and irrigation with filtered reclaimed wastewater treated with ultraviolet light. The monitored results showed that the concentrations of Cu, Cd, and Pb in soil during the experimental period were lower than initial soil levels before irrigation, whereas Zn increased in all treatment plots. However, the ranges of Zn, Cu, Cd and Pb in soil were below the soil pollution standards in the Republic of Korea. Heavy metal concentrations in vegetables showed insignificant variations for all treatments.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.267-270
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• 2003

This paper presents a recent finding from the progressed research efforts on the application for wastewater reclamation and reuse for agricultural uses. Reclaimed effluents from the Suwon municipal sewer treatment plant has been used to irrigate paddy rice at experimental plots. Three levels of reclamation treatments, filtration, disinfection, and the both, and one treatment to apply heavily polluted stream flow are compared to the control which uses groundwater for irrigation. The rice growth indicated by plant height and tiller number, and the yields were compared statistically among the five treatments. The results showed that the rice yields from polluted stream were greatest, and the control showed the lowest yields. And the first year experiment indicated that the agricultural reuse is promising.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1166-1172
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• 2007

Drainage pipeline system repaired by trenchless technology using liners can be defined between partial and entire collapse. The liners in the partial collapse pipeline are subjected to only uniform groundwater pressure on the surface. This research evaluates practical and useful cured-in-placed pipe (CIPP) design equations based on experimental results and finite element analysis results. Also, stability evaluation of pipe liner system with edge treatment is performed using finite element analysis. The CIPP equation should be used to design liner pipe system.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.51-61
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• 1997

The objective of this study is to evaluate the feasibility of Pumping-and-Treatment system (PTS) for remediation of the saturated zones contaminated with NAPLs. A simulation is carried out for the removal of DNAPLs (denser-than-water non-aqueous phase liquids) and LNAPLS (lighter-than-water non-aqueous phase liquids) distributing at and below the water table. In the study, LNAPL and DNAPL are assumed to be n-hexane and 1,1-dichloroacetone, respectively. The model system studied consists of four heterogeneous soil layers with different permeabilities. Groundwater flows through the bottom layer and a pumping well is located under the initial water table. The time-driven deformation of the water table and removal efficiency of contaminants are estimated after vacuum application to the inlet of the well. In the calculation, FVM (Finite Volumetric Method) with SIMPLEC algorithm is applied. Results show that removal efficiencies of both DNAPL and LNAPL are negligible for the first 5 days after the PTS operation. However, when the cone-shape water table is formed around the inlet of the pumping well, the rapid removal rate is obtained since NAPLs migrate rapidly through the curvature of the water table. The removal efficiency of DNAPL is estimated to be higher than that of LNAPL due to the gravity. The results also show that the fluctuation or cone-shaped depression of the water table enhances the removal efficiency of NAPLs in saturated zones. The simulation results could provide a basis of the PTS design for the removal of NAPLs in saturated zones.