• 한국지하수토양환경학회지:지하수토양환경
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• 제15권4호
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• pp.13-20
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• 2010

The purpose of this study was to develope the remediation method of contaminated soils with metals and petroleum. The diesel degrading strain was isolated and identified from the soil contaminated by petroleum at industrial sites. Diesel biodegradation experiment was performed by diesel degrading bacteria in both solution and soil slurry. Contaminated soils by Zn or As and diesel were treated consecutively by steam-vapor extraction, biodegradation, and acid washing. The strain was identified as Pseudomonas aeruginosa, and named as Pseudomonas aeruginosa TPH1. The optimal culture conditions of TPH1 were $20^{\circ}C$ and pH 7.0, 3% of diesel concentration. Biodegradation of diesel was performed using the separated strain in liquid medium, and 63% of diesel was degraded in 72 hours. And 52% of diesel was removed in the tested soils. In the treatment of contaminated soils with diesel and Zn or As, 29% ~ 44% of diesel was reduced by steamvapor extraction, 60% ~ 71% of diesel was removed after biodegradation. 47% of Zn and 96% of As were removed after acid(mixture of sulfuric and oxalic acids) washing. It is recommended that consecutive treatment method of steam-vapor extraction, biodegradation and acid washing is effective for remediation of complex contaminated soils with metals and petroleum.

• Journal of Microbiology and Biotechnology
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• 제33권7호
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• pp.886-894
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• 2023

During the rhizoremediation of diesel-contaminated soil, methane (CH₄), a representative greenhouse gas, is emitted as a result of anaerobic metabolism of diesel. The application of methantrophs is one of solutions for the mitigation CH₄ emissions during the rhizoremediation of diesel-contaminated soil. In this study, CH₄-oxidizing rhizobacteria, Methylocystis sp. JHTF4 and Methyloversatilis sp. JHM8, were isolated from rhizosphere soils of tall fescue and maize, respectively. The maximum CH₄ oxidation rates for the strains JHTF4 and JHM8 were 65.8 and 33.8 mmol·g-DCW^-1·h^-1, respectively. The isolates JHTF4 and JHM8 couldn't degrade diesel. The inoculation of the isolate JHTF4 or JHM8 significantly enhanced diesel removal during rhizoremediation of diesel-contaminated soil planted with maize for 63 days. Diesel removal in the tall fescue-planting soil was enhanced by inoculating the isolates until 50 days, while there was no significant difference in removal efficiency regardless of inoculation at day 63. In both the maize and tall fescue planting soils, the CH₄ oxidation potentials of the inoculated soils were significantly higher than the potentials of the non-inoculated soils. In addition, the gene copy numbers of pmoA, responsible for CH₄ oxidation, in the inoculated soils were significantly higher than those in the non-inoculated soils. The gene copy numbers ratio of pmoA to 16S rDNA (the ratio of methanotrophs to total bacteria) in soil increased during rhizoremediation. These results indicate that the inoculation of Methylocystis sp. JHTF4 and Methyloversatilis sp. JHM8, is a promising strategy to minimize CH₄ emissions during the rhizoremediation of diesel-contaminated soil using maize or tall fescue.

• Environmental Engineering Research
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• 제12권2호
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• pp.37-45
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• 2007

Phytoremediation has been used effectively for the biodegradation of oil-based contaminants, including diesel, by the stimulation of soil microbes near plant roots (rhizosphere). However, the technique has rarely been assessed for itsinfluence on soil microbial properties such as population, community structure, and diversity. In this study, the removal efficiency and characteristics of rhizobacteria for phytoremediation of diesel-contaminated soils were assessed using barnyard grass (Echinochloa crusgalli). The concentration of spiked diesel for treatments was around $6000\;mg\;kg^{-1}$. Diesel removal efficiencies reached 100% in rhizosphere soils, 76% in planted bulk soils, and 62% in unplanted bulk soils after 3weeks stabilization and 2 months growth(control, no microbial activity: 32%). The highest populations of culturable soil bacteria ($5.89{\times}10^8$ per g soil) and culturable hydrocarbon-degraders($5.65{\times}10^6$ per g soil) were found in diesel-contaminated rhizosphere soil, also yielding the highest microbial dehydrogenase. This suggests that the populations of soil bacteria, including hydrocarbon-degraders, were significantly increased by a synergistic rhizosphere + diesel effect. The diesel treatment alone resulted in negative population growth. In addition, we investigated the bacterial community structures of each soil sample based on DGGE (Denaturing Gel Gradient Electrophoresis) band patterns. Bacterial community structure was most influenced by the presence of diesel contamination (76.92% dissimilarity to the control) and by a diesel + rhizosphere treatment (65.62% dissimilarity), and least influenced by the rhizosphere treatment alone (48.15% dissimilarity). Based on the number of distinct DGGE bands, the bacterial diversity decreased with diesel treatment, but kept constant in the rhizosphere treatment. The rhizosphere thus positively influenced bacterial population density in diesel-contaminated soil, resulting in high removal efficiency of diesel.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권3호
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• pp.10-16
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• 2011

The experimental studies for remediation of diesel contaminated soils were performed using subcritical water in laboratory scale. Contaminated soils from industrial area and artificially contaminated soils were utilized for soil remediation. Experimental system was composed for subcritical water to flow upward through the soil packed column for extracting contaminants. 10 g of contaminated soil was packed into the column and water flow rate was 2 mL/min. To evaluate the effects of temperature, pressure and treatment time on the removal efficiency, temperature was changed from 100$^{\circ}C$ to 350$^{\circ}C$, pressure from 50 bar to 220 bar and treatment time at the predetermined temperature from 0 min to 120 min. The purification efficiency increased as temperature increased. However, the effect of pressure and treatment time was low. Temperature 250$^{\circ}C$, pressure 50 bar and treatment time 30 min were selected for optimal operating condition for this study.

• 한국환경과학회지
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• 제17권5호
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• pp.479-484
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• 2008

The application of microwave technology has been investigated in the remediation of diesel-contaminated soil. The paper deals with economic assessment by means of cost analysis and degradation characteristics at different microwave powers for total petroleum hydrocarbon (TPH) in diesel contaminated soils. The soils from S Mountain around the D University were sampled. The samples were screened with 2.0 mm mesh and dried for 6 hours before the diesel was added into the dried soils. The diesel-contaminated soil (3,300 mg THP/kg soil) was prepared with diesel (S Co.). The drying process was carried out in a microwave oven, a standard household appliance with a 2,450 MHz frequency and 700 W of power. The experiments were conducted from 0 to 20 minutes as the microwave powers increased from 350W to 500W to 700W. The concentrations of TPH were analysed using a gas chromatography/mass spectrometer (GC/MS). The initial concentration of TPH was 3,300 mg TPH/kg soil. The weight of contaminated soil was 200g. The concentration of TPH was decreased to 1,828 mg TPH/kg soil (44.7%), 1,347 mg TPH/kg soil (59.2%) and 1,014 mg TPH/kg soil (69.3%) at 350W, 500W and 700W for 15 minutes respectively. In addition, the curve was best fit with first order kinetics using the least-square method. The ranges of a first order rate constant k and r-square were $0.0298{\sim}0.0375min^{-1}$ and $0.9373{\sim}0.9541$ respectively.

• 한국지하수토양환경학회지:지하수토양환경
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• 제9권4호
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• pp.24-31
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• 2004

유류오염토양을 건설재료로 재활용할 수 있는 방안으로써 Cold Mix Asphalt(CMA) 처리를 제시하였고 디젤 및 디젤화합물로 오염된 토양의 CMA 처리특성을 고찰하였다. 양이온성 또는 음이온성 또는 비이온성 계면활성제를 함유하고 있는 5가지 아스팔트 이멀젼을 이용해서 디젤 오염토양의 처리능을 고찰한 결과 첨가된 계면활성제의 차이에 의한 성능의 차이는 확연하게 드러나지 않았으나, 토양과의 친밀성 및 흡착계수를 고려하여 Lauryl Dimethyl Benzyl Ammonium Chloride (LDBAC)를 포함한 이멀젼을 오염토양 처리에 적합한 아스팔트 이멀젼으로 선정하였다. 아스팔트 이멀젼 LDBAC에 의한 세가지 디젤화합물의 처리능은 docosane, pentadecane, undecane의 순으로 높은 것으로 나타났다. 아스팔트 이멀젼 LDBAC를 이용하여 CMA처리된 토양에 대한 용출실험결과 비교적 고농도인 10,000 mg/kg 의 디젤로 오염된 토양도 CMA처리 가능함을 확인하였다. 공시체로부터 디젤의 용출은 초기 4일까지는 확산에 의한 거동을 보여 주었고 그 이후로는 용출속도가 감소하여 총 용출가능양의 $50\%$ 이상이 유출되었다고 판단되는 depletion의 거동을 보여 주었다. CMA처리된 오염토양으로부터 3가지 디젤화합물의 총용출량은 undecane > pentadecane > docosane의 순서로 높은 것으로 나타났으며, pentadecane의 경우 CMA 처리시 양생속도가 상대적으로 더딘 것으로 밝혀졌다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.401-406
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• 2000

Spilling of petroleum hydrocarbons such as gasoline, motor oils, and diesel fuel from underground storage tanks (USTs) is a major source of contamination to ground water and soils. In response to the need of developing an effective and economical cleanup technique, this study investigates the effectiveness of using sonication to enhance the soil flushing method. The study involves laboratory testing, and the testing was conducted using a specially designed and fabricated device to determine the effect of sonication on contaminant removal. The sonication was applied at 20 kHz frequency under different power levels. Test soil was Joomoonjin Sand, and diesel fuel was used as a contaminant of soil flushing test. The results of the investigation show that sonication enhanced the contaminant removal from soils significantly, and the degree of enhancement varied with power levels of sonication. Based on the results of the study, it is concluded that the flushing method with sonication has a great potential to become an effective method for removing petroleum hydrocarbons from the contaminated ground.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.704-715
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• 2006

Oil spill was found in 1999 from a diesel storage facility located near the top of Baekun Mountain in Uiwang City. Application of bioremediation techniques was very relevant in removing oil spills in this site, because the geological condition was not amenable for other onsite remediation techniques. For efficient bioremediation, bacterial communities of the contaminated site and the uncontaminated control site were compared using both molecular and cultivation techniques. Soil bacterial populations were observed to be stimulated to grow in the soils contaminated with diesel hydrocarbon, whereas fungal and actinomycetes populations were decreased by diesel contamination. Most of the dieseldegrading bacteria isolated from contaminated forest soils were strains of Pseudomonas, Ralstonia, and Rhodococcus species. Denaturing gradient gel electrophoresis (DGGE) analysis revealed that the profiles were different among the three contaminated sites, whereas those of the control sites were identical to each other. Analysis of 16S rDNA sequences of dominant isolates and clones showed that the bacterial community was less diverse in the oil-contaminated site than at the control site. Sequence analysis of the alkane hydroxylase genes cloned from soil microbial DNAs indicated that their diversity and distribution were different between the contaminated site and the control site. The results indicated that diesel contamination exerted a strong selection on the indigenous microbial community in the contaminated site, leading to predominance of well-adapted microorganisms in concurrence with decrease of microbial diversity.

• 한국토양환경학회지
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• 제4권2호
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• pp.127-136
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• 1999

식물을 이용하여 토양이나 지하수 등의 매질로부터 오염물을 제거하는 기술인 phytoremediation은 지난 몇 년간 확용잠재성이 높은 환경복원기술로 많은 관심을 받아왔다. 본 연구에서는 현장조건을 모사한 그린하우스에서 이러한 phytoremediation에 의한 디젤로 오염된 토양의 정화효과를 조사하였다. 처리실험에 적합한 식물을 선정하기 위하여 인위적으로 디젤로 오염시킨 토양에서 증가에 따른 대상식물인 알팔파 옥수수, 피, 물피의 생장율 저하정도를 관측하여 내성이 강한 알팔파를 정화식물로 이용하였다. 디젤오염토양의 처리실험은 공기주입, 알팔파 파종, 공기주입과 알팔파 파종이 함께 적용된, PVC 파이프형태의 처리구에서 오염토양의 정화정도를 약 100일간 관측하였다. 칼럼 실험결과, 오염물의 제거속도에 기여하는 식물의 긍정적 효과가 관측되었으며 또한 지속적으로 토양내로 공기를 공급 하여줌으로써 Phytoremediation의 처리효율을 더욱 향상시킬 수가 있었다. 실험종료 후 각각의 처리구에서 토양 깊이별 미생물의 활성을 간접적으로 측정한 결과, 이러한 식물의 정화효과는 근권에 있는 토양미생물에게 유용한 뿌리 분비물을 지속적으로 제공함으로써 미생물의 활발한 번식 및 분해활동을 유지시켜 오염물의 분해를 더욱 촉진시키는 것으로 보인다.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.413-424
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• 2021

식물과 근권미생물을 이용해 토양 오염물질을 제거하는 rhizoremediation의 효율을 높이기 위해서는 오염물질을 제거함과 동시에 식물 생장을 촉진시키는 미생물 자원 개발이 필요하다. 본 연구에서는 중금속 및 유류 복합 오염 토양에서 서식하고 있는 옥수수와 톨페스큐의 근권으로부터 중금속(구리, 카드뮴 및 납) 내성을 가진 근권세균을 순수분리하였고, 식물 생장 촉진능, 중금속 내성능 및 디젤 분해능을 정성적으로 평가하였다. 그 결과 중금속 내성, 식물 생장 촉진 활성 및 디젤 분해능을 가진 6종의 균주를 분리하였다. 옥수수 근권에서 분리한 CuM5와 CdM2 균주는 Cupriavidus sp.로 동정되었다. 톨페스큐 근권에서 분리한 CuT6, CdT2, CdT5 및 PbT3는 각각 Fulvimonas soli, Cupriavidus sp., Novosphingonium sp. 및 Bacillus sp.로 동정되었다. Cupriavidus sp. CuM5와 CdM2는 중금속 내성과 디젤 분해능은 상대적으로 낮았으나, 식물 생장 촉진능이 상대적으로 우수하였다. 6종 중에서 디젤 분해능이 가장 우수한 균주는 Cupriavidus sp. CdT2와 Bacillus sp. PbT3이었다. 특히, Bacillus sp. PbT3는 3종의 중금속에 대해 상대적으로 우수한 내성을 가졌고 식물 생장 촉진능도 우수하였다. 본 연구에서 분리한 근권세균은 유류와 중금속 복합 오염 토양을 정화시키며 식물 생장을 촉진시키는 새로운 미생물 자원으로 활용 가능하다.