• Journal of Soil and Groundwater Environment
• /
• v.13 no.6
• /
• pp.23-30
• /
• 2008

Air sparging technique has been used for remediation of VOC(volatile organic compound)-contaminated aquifer. The aim of this study was to develop an innovative air sparging technique that enhances the efficiency of air intrusion into a specific horizontal layer of aquifer where the contaminants exist with the help of water-soluble surfactant. A twodimensional physical box model, packed with homogeneous sand, was used for simulating the aquifer in this study. Aqueous solution of anionic surfactant (100 mg/L, sodium dodecylbenzene sulfonate) was used to suppress the surface tension of groundwater. Three sets of experiments were conducted: air sparging experiment without surfactant application, air sparging experiments for box model where the surfactant solution was applied right above the air injection point, and air sparging experiments with surfactant solution layer formed in the middle of the box. It was found that the sparging influence zone was expanded up to five times of that formed by sparging without surfactant application. The size of sparging influence zone was more sensitive to the air flow (injection) rate with surfactant application than that without surfactant. More importantly, injection of air into the target aquifer layer was successful with surfactant application. Findings in this study are expected to provide more options for designing remediation processes using air sparging.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.05a
• /
• pp.59-63
• /
• 2000

At military bases, environmental restoration activities resulting from oil contamination are growing concerns of preventing adverse effects on human health and environments. Its technologies are still under developing stage through some countries such as United States and Germany. This study is focused on developing model for a decision-maker to assist the restoration priority under the situation of limited resources such as budget and time. The Model, named the Base Restoration Priority Decision model(BRP model), is composed of the three factors : oil contaminants receptors, and the potential migration pathways. Each risk rating of factor is combined in the 27 matrix blocks and set immediate, moderate, and delayed action category designated restoration priority. This is categorized to group sites into three degree using the simplest of assessment system. As a result, the model will be able to apply to the effective allocation of resources for the restoration by any decision-maker because the model is easy to understand. Also, the continuous study will have established risk assessment system for the restoration of contaminated military with this study as the starting point.

• Journal of Conservation Science
• /
• v.28 no.3
• /
• pp.235-245
• /
• 2012

Nondestructive deterioration diagnosis has been carried out for the former ore dressing plant of the Yongwha mine in Yeongyang (Registered Cultural Property No. 255). Deterioration rates about organic contaminant and soil of the upper part (7 to 13 layer) indicate higher than the lower part (1 to 6 layer) of the ore dressing plants. By contrast, deterioration rates such as crack, break out and discoloration of the lower part indicate very higher than the upper part. It is estimated that the plants of the lower part that mechanical and chemical process had been done for flotation were damaged severely by physicochemical weathering with reaction of concrete and chemical solution. As results of ultrasonic velocity measurement, average p-wave velocity of plants were measured 2,462m/s (compressive strength $529kgf/cm^2$). As for the analytical results of surface contaminants and soil compositions using P-XRF, they were identical with major elements (Cu, Zn, Pb, Fe and As) of ore minerals from the Yongwha mine. Therefore, the ore dressing plant should be treated by phytoremediation with conservation because heavy metals could impinged upon plants and natural environment.

• The Korean Journal of Pesticide Science
• /
• v.20 no.1
• /
• pp.7-13
• /
• 2016

As of many organochlorine pesticides, polychlorinated biphenyls are ubiquitous organic contaminants, which can be found in the most environmental matrices. Their toxic effects include endocrinedisrupting activity. Most researches with these toxicants performed with mixtures of congeners, namely Aroclor and related study has been done in complex environmental matrix, rather than single biosystems or pure congeners. 5 congeners were synthesized and their fates in pure microbial culture (Aspergillus niger) were determined in this study. Among biphenyl and synthetic congeners, biphenyl, PCB-1 (2-chlorobiphenyl), and PCB-3 (4-chlorobiphenyl) were rapidly transformed to hydrophilic metabolites, followed by PCB-38 (3,4,5-trichlorobiphenyl), while the degradation of PCB-126 (3,3',4,4',5-pentachlorobiphenyl) was not observed. The amounts of transformation for biphenyl, PCB-1, PCB-3, and PCB-38 were 65, 38, 52, and 2% respectively. The major metabolites of the above congeners were identified as mono- and di-hydroxy biphenyls, which are known to give adverse endocrinological effects.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.3
• /
• pp.231-239
• /
• 2005

This study was performed to investigate adsorption characteristics of MTBE and Cd depending upon types of clay minerals md their physicochemical properties. The adsorption characteristics were examined by batch adsorption test on various experimental parameters such as adsorption time, ratio of solution to soil, concentration of contaminants, content of organic matter, pH, and zeta potential. The adsorption efficiency of MTBE or Cd for three types of clays decreased in response to the increase of the ratio of solution to soil whereas their adsorbed amounts increased. MTBE was greatly adsorbed in the decreasing order of vermiculite, bentonite, and CTAB-bentonite while Cd was adsorbed in the decreasing order of bentonite, vermiculite, and CTA-bentonite. An equilibrium isotherm for MTBE was well fitted to Freundlich plotting whereas that for Cd was closely corresponded to Langmuir isotherm. The adsorbed amount of MTBE on bentonite and vermiculite showed the maximum at 1% and 5% of humic acid, thereafter diminished while the adsorbed amount of MTBE on CTAB-bentonite increased in proportion to humic acid. Conversely, the adsorbed amount of Cd on the addition of humic acid continued to increase regardless of types of adsorbents. For all types of adsorbents, adsorbed quantity and adsorption efficiency of Cd have been coincidently increased at pH 8 and they were further enhanced at pH 10 showing 90% adsorption efficiency. Upon pH rose, the zeta potential on each adsorbent began to decrease, while increasing Cd concentration led to decline of zeta potential, which in turn ascribed to lowering dispersion stability that could consequently enhance adsorption capability.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.9 no.2
• /
• pp.77-86
• /
• 2001

As construction and expansion of wastewater treatment works is continuing, generation of sludge is increasing. Bur most sludge is not used appropriately but disposed by landfill dumping to sea. Furthermore direct landfilling of sludge cake containing moisture content over 75% has been legally prohibited since 2001 that's enforcement will be more strict in 2003. Such a situation means nowadays recycling of organic waste such as sludge and food waste is necessary. Composting is one of recycling methods commonly and used as an effective means of stabilizing organic waste and then compost can be used as fertilizer. However fertilizer law management which include standard of compost products and other fertilizers applied all sludge products indiscriminiately and was not flexible. So MOE has graded organic composts according to land applications to improve recycle of organic wastes. The classified organic compost which contains low contaminants has been possible to use as various purpose. This study enalyzed 30 samples which were raw materials for compost and compost products management well and to estimate the quality of compost products. Heavy metals were measured in Raw materials and OM/N, NaCl and VS were tested in compost products as well as heavy metals. As a result, approximate 10% of raw materials was not suitable to the grade A and 6.7% over the grade B of the regulation on raw materials for compost. In the case of 30 produced compost propducts approximate, 57% of composts was not compatible with the grade A and B of the regulation on composting product. The qualities of compost products were worse than raw materials, because the compost products have more regulation item raw materials have.

• The Journal of Engineering Geology
• /
• v.22 no.3
• /
• pp.253-262
• /
• 2012

With the aim of remediating soils contaminated by heavy metals and oil, experimental research was conducted to evaluate the optimal design factors for remediation in terms of efficient soil washing methods and processes. The experiments employed absorptiometric analysis and gas chromatography methods to reduce the concentration of heavy metals such as cooper (Cu), lead (Pb), and zinc (Zn), and total petroleum hydrocarbons (TPH) in contaminated soils. The experimental processes consisted of deciding on the washing solution, washing time, and dilution ratio for contaminated soils. A dissolution analysis of heavy metals was then performed by the addition of surfactant, based on the results of the decision experiments, and the injection processes of microbes and hydrogen peroxide were selected. The experimental results revealed that reduction effects in contaminated soils under the experimental conditions were most efficient with hydrochloric acid 0.1 mole, washing time 1 hour, and dilution ratio 1:3, individually. Additional reduction effects for heavy metals and TPH were found with the addition of a washing solution of 1% of surfactant. The addition of microbes and hydrogen peroxide caused a reduction in TPH concentration.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.6
• /
• pp.53-64
• /
• 2009

Wetlands can remove organic contaminants, metals and radionuclides from wastewater through various biogeochemical mechanisms. In this study, a mathematical model was developed for simulating the fate and transport of chemical species in marsh wetland sediments. The proposed model is a one-dimensional vertical saturated model which is incorporated advection, hydrodynamic dispersion, biodegradation, oxidative/reductive chemical reactions and the effects from external environments such as the growth of plants and the fluctuation of water level due to periodic tides. The tidal effects causes periodic changes of porewater flow in the sediments and the evapotranspiration and oxygen supply by plant roots affect the porewater flow and redox condition on in the rhizosphere along with seasonal variation. A series of numerical experiments under hypothetical conditions were performed for simulating the temporal and spatial distribution of chemical species of interests using the proposed model. The fate and transport of a trace metal pollutant, chromium, in marsh sediments were also simulated. Results of numerical simulations show that plant roots and tides significantly affect the chemical profiles of different electron acceptors, their reduced species and trace metals in marsh sediments.

• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.77-86
• /
• 1999

Partitioning of two hydrophobic organic compounds (HOCs), phenanthrene and naphthalene, to kaolinite and sorbed surfactants was studied to evaluate the feasibility of surfactant-enhanced remediation (SER) of contaminated subsurface systems. Sorbed surfactant partition coefficients. $K_ss$, showed a strong dependence on the surfactant sorption isotherms at low sorbed surfactant levels $K_ss$ values were at their highest and then decreased with increasing surfactant sorption densities. $K_ss$ values for SDS were always larger than corresponding $K_mic$values. For Tween 80, however. $K_ss$ values $K_mic$ were higher than $K_mic$ values only at the lower sorbed surfactant densities. HOC distribution between immobile and mobile phases varied with surfactant dose distribution coefficients increased initially with increasing surfactant concentrations and then decreased at higher doses. This observation shows directly the competition between sorbed and micellar surfactants for HOC partitioning. Overall results of this study demonstrate that surfactant sorption to the solid phase can lead to increases in HOC retardation in some SER applications. Therefore, before an SER process is selected, appropriate consideration of surfactant sorption and HOC partitioning to immobile versus mobile phases pertinent to a specific subsurface system must be contemplated.

• Journal of the Korean Society of Groundwater Environment
• /
• v.6 no.3
• /
• pp.152-157
• /
• 1999

Oil leaked from underwound storage tanks and leachate from sanitary landfills have been known as contaminant sources of the high-quality groundwater resources. The mobility of contaminants in the aquifer largely depends on the groundwater flow and the determination of associated hydraulic parameters is essential for a proper remediation of contaminated grnundwater. This study aimed at determining an optimum set of hydraulic parameters for an unconfined sandy aquifer of a laboratory scale through comparison of various methods. Results showed that the specific yield obtained from gravity drainage experiment was an average of 0.20 with minor variations in aquifer depths. and the permeabilities obtained from Dupuit approximation and slug test gave similar values of 5.33 cm/min and 5.85 cm/min but the constant head method gave 0.17 cm/min, which is much ion than the other methods. This experimental evidence reveals that the permeability of the unconfined sandy aquifer could be accurately determined by Dupuit assumption or slug tut rather than by constant head method conducted for a disturbed separate soil column.