• Korean Journal of Microbiology
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• v.41 no.3
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• pp.201-207
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• 2005

A phenanthrene-degrading bacterium HS362, which is capable of using phenanthrene as a sole carbon and energy source, was isolated from oil contaminated soil. This strain is a gram negative, rod shaped organism that is most closely related to Sphingomonas paucimobilis based on biochemical tests, and belongs to the genus Sphingomonas based on fatty acids analysis. It exhibited more than $99.2{\%}$ nucleotide sequence similarity of 16S rDNA to that of Sphingomonas CF06. Thus, we named this strain as Sphingomonas sp. HS362. It degraded $98{\%}$ of phenanthrene after 10 days of incubation when phenanthrene was added at 500 ppm and $30{\%}$ even when phenanthrene was added at 3000 ppm. Sphingomonas sp. HS362 could also degrade low molecular weight PAHs(Polycyclic aromatic hydrocarbons) such as indole and naphthalene, but was unable to degrade high molecular weight PAHs such as pyrene and fluoranthene. The optimum temperature and pH for phenanthrene degradation were $30^{\circ}C$ and $4{\~}8$, respectively. Sphingomonas sp. HS362 could degrade phenanthrene effectively in the concentration range of NaCl of up to $1{\%}$. Its phenanhrene degrading ability was enhanced by preculture, suggesting the possibility of induction of phenanthrene degrading enzymes. Starch and surfactants such as SDS, Tween 85, and Triton X-100 were also able to enhance phenanthrene degradation by Sphingomonas sp. HS362. It carries five plasmids and one of them, plasmid p4, is considered to be involved in the degradation of phenanthrene according to the plasmid curing experiment by growing at $42^{\circ}C$.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1329-1336
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• 2011

The objectives of this study are to examine the processing of oils contamination soil by means of using a micronano-bubble soil washing system, to investigate the various factors such as washing periods, the amount of micro-nano bubbles generated depending on the quantity of acid injection and quantity of air injection, to examine the features involved in the elimination of total petroleum hydrocarbons (TPHs) contained in the soil, and thus to evaluate the possibility of practical application on the field for the economic feasibility. The oils contaminated soil used in this study was collected from the 0~15 cm surface layer of an automobile junkyard located in U City. The collected soil was air-dried for 24 hours, and then the large particles and other substances contained in the soil were eliminated and filtered through sieve No.10 (2 mm) to secure consistency in the samples. The TPH concentration of the contaminated soil was found to be 4,914~5,998 mg/kg. The micronano-bubble soil washing system consists of the reactor, the flow equalization tank, the micronano- bubble generator, the pump and the strainer, and was manufactured with stainless material for withstanding acidic phase. When the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 30 minutes were respectively identified as 4,931 mg/kg (18.9%), 4,678 mg/kg (18.9%) and, 4,513 mg/kg (17.7%). And when the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 120 minutes were respectively identified as4,256 mg/kg (22.3%), 4,621 mg/kg (19.7%) and 4,268 mg/kg (25.9%).

• Journal of Soil and Groundwater Environment
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• v.8 no.4
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• pp.45-52
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• 2003

A gas-substrate degrading bacterium, Nocardia SW3, was isolated from the gasoline contaminated aquifer using propane and butane as carbon and energy sources. We have examined the effects of substrate concentration, temperature and pH on the gas substrate degradation as well as MTBE cometabolic degradation. The result for the effect of substrate concentration showed that the maximum degradation rates of propane and butane were 30.6 and 25.4 (n㏖/min/mg protein) at 70 $\mu$㏖, respectively. The optimum temperature and pH for the degradation of gas substrate were $30^{\circ}C$ and 7, respectively. Substrate degradation activity, however, was still active in broad range of pH from 5 to 8 and temperature between $15^{\circ}C$and$35^{\circ}C$. The degradation activity of Nocardia SW3 for the MTBE was similar to the both substrates. The observed maximal transformation yields ($T_y$) were 46.7 and 35.0 (n㏖ MTBE degraded $\mu$㏖ substrate utilized), and the maximal transformation capacities ($T_c$) were 320 and 280 (n㏖MTBE degraded/mg biomass used) for propane and butane oxidizing activity on MTBE, respectively. And also, TBA was detected as by-product of MTBE and it was continuously degraded further.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1285-1291
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• 2005

In this study, we isolated bacteria from petroleum contaminated soil which were near to underground storage tanks(UST). Through the screen test, we selected high efficiency bacterium, KDi19, for biodegradation of diesel. KDi19 was identified as Pseudomonas sp. by 16S rDNA, fatty acid, and morphological physiological characteristics. KDi19 degraded 956.3 mg/L(95.6%) of 1,000 mg/L diesel for 48 hours(incubation condition : temperature; $30^{\circ}C$, cell concentration; 1.0 g/L, pH 7). At low temperature, $20^{\circ}C$, $15^{\circ}C$, $10^{\circ}C$, KDi19 respectively removed 63.9%, 18.5% and 17.0% of 1,000 mg/L diesel for 48 hours(cell concentration 1.0 g/L, pH 7). At low concentration of diesel, 50 mg/L and 100 mg/L, KDi19 degraded 97.9% and 96.2% of diesel for 24 hours(temperature; $30^{\circ}C$, cell concentration: 1.0 g/L, pH 7), respectively.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1851-1859
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• 2000

Crude oil-degrading bacteria were isolated from the sites contaminated by oil products. The isolates were identified as Acinetobacter sp. A132, Pseudomonas putida A422, Pseudomonas aeruginosa F721, F722, and Xanthomonas maltophilia B823. The results of investigation on the degradability of crude oil indicated that the strain A132 had the highest rate of $6.04g/L{\cdot}day$. Also, the strain A132 and F722 almost degraded each of n-alkane compounds between $nC_{10}$ and $nC_{32}$. The strain A422 degraded benzene and xylene but not n-alkane. The strain B823 grew somewhat in crude oil but did not entirely degrade other substrates used in this study. The results of the GC/FID analysis on the degradability of the mixed n-alkane compounds showed that the strain F722 could degrade 100% of the compounds with $nC_7{\sim}nC_{10}$ and more than 80% of those with $nC_{11}{\sim}nC_{24}$.

• Journal of Korean Society on Water Environment
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• v.32 no.3
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• pp.243-252
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• 2016

In cases of water pollution accidents, accurate prediction for arrival time and concentration of contaminants in a river is essential to take proper measures and minimize their impact on downstream water intake facilities. It is critical to fully understand the behavior characteristics of contaminants on river surface, especially in case of oil spill accidents. Therefore, in this study, the effects of main parameters of advection and diffusion of contaminants were analyzed and validated by comparing the results of Lagrangian particle tracking (LPT) simulation of Environmental Fluid Dynamic Code (EFDC) model with those of Global Position System (GPS)-equipped drifter experiment. Prevention scenario modeling was accomplished by taking cases of movable weir operation into account. The simulated water level and flow velocity fluctuations agreed well with observations. There was no significant difference in the speed of surface particle movement between 5 and 10 layer modeling. Therefore, 5 layer modeling could be chosen to reduce computational time. It was found that full three dimensional modeling simulated wind effects on surface particle movements more sensitively than depth-averaged two dimensional modeling. The diffusion range of particles was linearly proportional to horizontal diffusivity by sensitivity analysis. Horizontal diffusivity estimated from the results of GPS-equipped drifter experiment was 0.096 m²/sec, which was considered to be valid for applying the LPT module in this area. Finally, the scenario analysis results showed that particle movements could be stagnant when discharge from the upstream weir was reduced, implying the possibility of securing time for mitigation actions such as oil boom installation and wiping oil contaminants. The outcomes of this study can help improve the prediction accuracy of particle tracking simulation to establish the most suitable mitigation plan considering the combination of movable weir operation.

• Journal of Soil and Groundwater Environment
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• v.20 no.1
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• pp.1-6
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• 2015

The objectives of this study were to calculate the radius of influence (ROI) of well for an air-sparging (AS)/soil vapor extraction (SVE) system and to evaluate the applicability of the system applied for the remediation of the petroleum contaminated rail site. For air permeability test, three monitoring wells were installed at a location of 1.3 m, 2.3 m, 3.0 m from the extraction well. And the pressure of each monitoring well was measured by extracting air from the extraction well with the pressure and flow of $(-)2,600mmH_2O$ and $1.58m^3/min$. The ROI for an extraction well was calculated as 4.31 m. Air was injected into the injection well with the pressure and flow of $3,500mmH_2O$ and $0.6m^3/min$ to estimate the radius of influence for oxygen transfer. Oxygen concentrations of air from three monitoring wells were measured. The ROI of an injection well for oxygen transfer was calculated as 3.46 m. The 28 extraction wells and 19 injection wells were installed according to the ROI calculated. The AS/SVE system was operated eight hours a day for five months. The rail site was contaminated with the petroleum and concentrations of benzene, toluene, and xylene were over the 'Worrisome Standard' of the 'Soil Environment Conservation Act'. The contaminated area was estimated as $732m^2$ and contaminants were dispersed up to (-)3 m from the ground. During the operation period, soil samples were collected from 5 points and analyzed periodically. With the AS/SVE system operation, concentrations of benzene, toluene, and xylene were decreased from 7.5 mg/kg to 2.0 mg/kg, from 32.0 mg/kg to 23.0 mg/kg, from 35.5 mg/kg to 23.0 mg/kg, respectively. The combined AS/SVE system applied to the rail site contaminated with volatile organic compounds (VOCs) exhibited a high applicability. But the concentration of contaminants in soil were fluctuated due to the heterogeneous of soil condition. Also the effect of the remediation mechanisms was not clearly identified.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.215-221
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• 2005

It was characterized the hexane biodegradation and mineralization using a hexane-degrading consortium, and analyzed its bacterial community structure by 16S rDNA PCR-DGGE (denaturing gradient gel electrophoresis). The specific growth rate (${\mu}_{max}$) of the hexane-degrading consortium was 0.2 $h^{-1}$ in mineral salt medium supplemented with hexane as a sole carbon source. The maximum degradation rate ($V_{max}$) and saturation constant ($K_{s}$) of hexane of the consortium are 460 ${\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$ and 25.87 mM, respectively. In addition, this consortium could mineralize $49.1{\%}$ of $^{14}C$-hexane to $^{14}CO_2$, and $43.6{\%}$ of $^{14}C$-hexane) was used for the growth of biomass. The clones isolated from the DGGE bands were closely related to the bacteria which were capable of degrading pollutants such as oil, biphenyl, PCE, and waste gases. The hexane-degrading consortium obtained in this study can be applied for the biological treatment of hexane.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.381-391
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• 2008

The eigenvalue technique is introduced to overcome the problem of truncation errors caused by temporal discretization of numerical analysis. The eigenvalue technique is different from simulation in that only the space is discretized. The spatially discretized equation is diagonized and the linear dynamic system is then decoupled. The time integration can be done independently and continuously for any nodal point at any time. The results of eigenvalue technique are compared with the exact solution and FEM numerical solution. The eigenvalue technique is more efficient than the FEM to the computation time and the computer storage in the same conditions. This technique is applied to the solute transport analysis in nonuniform flow fields around underground storage caverns. This method can be very useful for time consuming simulations. So, a sensitivity analysis is carried out by using this method to analyze the safety of caverns from nearly located contaminant sources. According to the simulations, the reaching time from source to the nearest cavern may takes 50 years with longitudinal dispersivity of 50 m and transversal dispersivity of 5 m, respectively.