• 한국지반환경공학회 논문집
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• 제11권10호
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• pp.49-55
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• 2010

에너지원 및 다양한 화학제품의 원료로 유류의 소비량이 증가함에 따라 유류의 유출사고가 빈번하게 발생하고 있다. 유류오염 지하수 처리를 위해 용존공기부상법이 사용되어지고 있으나 용해성 기름을 효과적으로 제거하지 못하고 있는 실정이다. 따라서 지하수내 주오염원인 자유상 유류와 친수성(oil-in water) 또는 친유성 에멜젼(water-in oil) 상태의 기름과 용해성 기름을 효과적으로 저감하는 것이 필요하다. 본 연구에서는 용존공기부상법에 펜톤 산화 공법을 사용하여 효과적인 유류 오염 지하수 처리를 연구하였다. 펜톤 실험 결과 TPH(Total Petroleum Hydrocarbon) 제거를 위한 최적 조건은 pH 3, $H_2O_2$ 주입농도 25mM과 $Fe^{2+}$ 주입농도 25mM으로 나타났다. DAF와 펜톤 산화 실험을 수행한 결과 7분내에 TPH(Total Petroleum Hydrocarbon)와 COD(Chemical Oxygen Demand) 농도가 각각 1.5mg/L와 40.0mg/L 이하로 감소하는 것으로 나타났다. 하지만 펜톤 산화 반응으로 인하여 슬러지 농도가 약 5배 가량 증가하여 후단에 침전조를 설치하는 것이 바람직하다.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1966-1974
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• 2008

A typical tropical soil from the northeast of Brazil, where an important terrestrial oil field is located, was accidentally contaminated with a mixture of oil and saline production water. To study the bioremediation potential in this area, molecular methods based on PCR-DGGE were used to determine the diversity of the bacterial communities in bulk and in contaminated soils. Bacterial fingerprints revealed that the bacterial communities were affected by the presence of the mixture of oil and production water, and different profiles were observed when the contaminated soils were compared with the control. Halotolerant strains capable of degrading crude oil were also isolated from enrichment cultures obtained from the contaminated soil samples. Twenty-two strains showing these features were characterized genetically by amplified ribosomal DNA restriction analysis (ARDRA) and phenotypically by their colonial morphology and tolerance to high NaCl concentrations. Fifteen ARDRA groups were formed. Selected strains were analyzed by 16S rDNA sequencing, and Actinobacteria was identified as the main group found. Strains were also tested for their growth capability in the presence of different oil derivatives (hexane, dodecane, hexadecane, diesel, gasoline, toluene, naphthalene, o-xylene, and p-xylene) and different degradation profiles were observed. PCR products were obtained from 12 of the 15 ARDRA representatives when they were screened for the presence of the alkane hydroxylase gene (alkB). Members of the genera Rhodococcus and Gordonia were identified as predominant in the soil studied. These genera are usually implicated in oil degradation processes and, as such, the potential for bioremediation in this area can be considered as feasible.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권6호
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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.

• 원예과학기술지
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• 제30권4호
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• pp.442-448
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• 2012

최근 상추와 같은 농산물에 의한 식중독사고가 발생하고 있으며 그 원인으로 병원성 미생물에 오염된 퇴비, 관개용수의 사용이라고 보고되고 있다. 따라서 본 연구는 육묘단계의 상토, 재배과정의 토양, 관개용수의 Escherichia coli와 Bacillus cereus 오염이 상추의 안전성에 미치는 영향을 구명하고자 수행하였다. 이를 위하여 상토는 두 균주로 7.5log CFU/g 수준으로 오염시킨 후 상추종자를 파종하고 28일간 생육시켰고, 오염되지 않은 토양과 6.0log CFU/g 수준으로 오염시킨 토양에 오염된 상토에서 21일간 자란 묘를 이식하고 49일간 인공기상동 ($25^{\circ}C$, 상대습도 70-80%)에서 생육시켰다. 또한 8.0log CFU/mL로 오염된 관개용수로 지표면관수법과 살수관수법으로 상추에 관수하고 40일간 병원성 미생물의 오염 및 생존을 조사하였다. 그 결과 육묘기의 상토와 상추 중 E. coli와 B. cereus는 시간이 경과함에 따라 점차 감소하였지만 육묘기 내내 생존 가능한 것으로 확인되었다. 토양에서는 42일간 E. coli와 B. cereus가 6.0log CFU/g 내외로 유의적인 감소 없이 유지되고 있었다. 오염된 토양에 이식된 상추는 21일째까지 E. coli와 B. cereus의 농도가 4.0log CFU/g 이상 유지되었고 이식 후 42일까지도 검출되었다. 또한 살수관수법으로 처리한 구에서 지표면관수법으로 처리한 구보다 상추의 오염수준이 5.0log CFU/g 정도 높았다. 따라서 본 연구의 결과는 병원성미생물에 오염된 상토, 토양, 관개용수는 농산물의 병원성미생물 오염에 직접적인 원인이 될 수 있음을 시사한다.

• Environmental Engineering Research
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• 제15권4호
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• pp.225-230
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• 2010

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of $600^{\circ}C$ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of $300^{\circ}C$ would be the most economic conditions.

• 한국환경과학회지
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• 제18권4호
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• pp.473-478
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• 2009

The removal characteristics of total petroleum hydrocarbons (TPHs) and heavy metals in contaminated soils with ultrasonic washing have been studied. The ultrasonic washing was evaluated on a laboratory scale. In this investigation, the effects of factors such as ultrasonic frequency, power intensity, duration of irradiation, contents of the TPHs and heavy metals and mixing ratios between the contaminated soils and water, were considered. Experimental results suggested that the rates for contaminant extraction of the TPHs and heavy metals in the contaminated soil increased considerably with the ultrasonic washing. Therefore, the ultrasonic washing has previously been to be an effective method to remediate the contaminated soils with the TPHs and heavy metals.

• 한국물환경학회지
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• 제21권4호
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• pp.403-409
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• 2005

Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by BTEX and MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc. In oil-contaminated environments, anaerobic biodegradation of BTEX and MTBE depended on the concentration and distribution of terminal electron acceptor. In this study, effect of electron acceptor on the anaerobic biodegradation for BTEX and MTBE-contaminated soil was investigated. This study showed the anaerobic biodegradation of BTEX and MTBE in two different soils by using nitrate reduction, ferric iron reduction and sulfate reduction. The soil samples from the two fields were enriched for 65 days by providing BTEX and MTBE as a sole carbon source and nitrate, sulfate or iron as a terminal electron acceptor. This study clearly shows that degradation rate of BTEX and MTBE with electron acceptors is higher than that without electron acceptors. Degradation rate of Ethylbenzene and Xylene is higher than that of Benxene, Toluene, and MTBE. In case of Benzene, Ethylbenzene, and MTBE, nitrate has more activation. In case of Toluene and Xylene, sulfate has more activation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권2호
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• pp.20-27
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• 2005

밀집된 축사의 영향으로 충적층 지하수가 질산성 질소로 심하게 오염되어 있는 소유역을 흐르는 화봉천 수질의 계절 변화를 연구하였다. 이 하천에서 축산폐수의 직접 유입이 확인되었으며, 오염된 지하수 유입으로 인한 수질 변화가 나타났다. 건기에는 축산폐수의 직접 유입이 하천수질에 큰 영향을 미치고 있다. 우기에는 강수에 의한 희석효과에도 불구하고 지표수의 질산성 질소 농도가 오히려 증가하였으며, 질산성 질소로 오염된 지하수 유입량 증가가 큰 영향을 미친 것으로 판단된다. 지하수의 하천 유출은 산소, 수소 동위원소 조성을 이용하여 증명하였다. 질산성 질소 농도는 화봉천이 청미천보다 상대적으로 높으므로, 화봉천 유업에 의해 청미천의 질산성 질소 농도가 증가되고 있으며, 하천수의 질산성 질소 농도가 높아지는 우기에 이러한 수질 영향이 더욱 커졌다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권6호
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• pp.13-17
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• 2014

Subcritical water acts like an organic solvent at elevated temperature in terms of its physicochemical properties. Taking into account this advantage, the remediation experiments of benzo[a]pyrene contaminated soil (8.45 mg/kg of initial concentration) were conducted using subcritical water extraction apparatus. The effect of operating factors on the removal efficiency was studied at the varying the conditions of the water temperature ranging $200{\sim}300^{\circ}C$, extraction time 30~90 min, and flow rate 0.3~2.0 mL/min. 12 g of benzo[a]pyrene contaminated soil was inserted into the extraction cell and placed into the reactor and then the subcritical water was driven through the cell. In this study, the removal efficiency of benzo[a]pyrene was increased from 55.1 to 98.1% when the temperature increased from 200 to $300^{\circ}C$. The removal efficiency was decreased from 97.0 to 77.0% when the flow rate increased from 0.3 to 2.0 mL/min, suggesting that the extraction is limited by intra-particle diffusion. The 30 min reaction time was determined as an effective treatment time at $250^{\circ}C$. Based on the results, the optimum condition for the remediation of benzo[a]pyrene contaminated soil was suggested to be $250^{\circ}C$, 30 min, and 0.3 mL/min.

• Environmental Engineering Research
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• 제23권2호
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• pp.175-180
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• 2018

Box-Behnken Design (BBD) under response surface methodology (RSM) was implemented to optimization the operating parameters and assess the removal and recovery efficiencies of crude oil from contaminated soil using subcritical water extraction. The effects of temperature, extraction time and water flow rate were explored, and the results indicate that temperature has a great impact on crude oil removal and recovery. The correlation coefficients for oil removal ($R^2=0.74$) and recovery ($R^2=0.98$) suggest that the proposed quadratic model is useful. When setting the target removal and recovery (>99%), BBD-RSM determined the optimum condition to be a temperature of $250^{\circ}C$, extraction time of 120 min, and water flow rate of 1 mL/min. An experiment was carried out to confirm the results, with removal and recovery efficiencies of 99.69% and 87.33%, respectively. This result indicates that BBD is a suitable method to optimize the process variables for crude oil removal and recovery from contaminated soil.