• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.72-79
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• 2016

Bioremediation is one of the most effective ways to remediate TPH-contaminated sites. However, under actual field conditions that are not at the optimum temperature, degradation of microorganisms is generally reduced, which is why the efficiency of biodegradation is known to be significantly affected by the soil temperature. Therefore, in this study, the labscale experiment was conducted using indigenous crude oil degrading microorganisms isolated from crude oil contaminated site to evaluate the remediation efficiency. Crude oil degrading microorganisms were isolated from crude oil contaminated soil and temperature, which is a significant factor affecting the remediation efficiency of land farming, was adjusted to evaluate the microbial crude oil degrading ability, degradation time, and remediation efficiency. In order to assess the field applicability, the remediation efficiency was evaluated using crude oil contaminated soil (average TPH concentration of 10,000 mg/kg or more) from the OO premises. Followed by the application of microorganisms at 30℃, the bioremediation process reduced its initial TPH concentration of 10,812 mg/kg down to 1,890 mg/kg in 56 days, which was about an 83% remediation efficiency. By analyzing the correlation among the total number of cells, the number of effective cells, and TPH concentration, it was found that the number of effective microorganisms drastically increased during the period from 10 to 20 days while there was a sharp decrease in TPH concentration. Therefore, we confirmed the applicability of land farming with isolated microorganisms consortium to crude oil contaminated site, which is also expected to be applicable to bioremediation of other recalcitrant materials.

• 한국미생물·생명공학회지
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• 제39권2호
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• pp.161-167
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• 2011

본 연구실에서 확보한 diesel 분해 고효율 균주 Pseudomonas putida KDi 19, kerosene 분해 고효율 균주 P. aeruginosa K14, gasoline 분해 고효율 균주 P. putida G8, BTEX 분해 고효율 균주 P. putida BJ10, P. putida E41의 5개의 고효율 균주를 컬럼 및 반응기에 적용하여 TPH의 생물학적 분해 실험에 적용하였다. 영양염류 및 산소 농도, 균농도 등 최적의 환경인자 도출을 통해 최적의 생물학적 처리 효율을 TPH의 경우, MSM 및 activator I을 주입하여 25일 동안 76.3%의 제거 효율과 제거속도상수 K=0.711를 나타냈으며, diesel의 경우 40일 동안 99.2%의 제거 효율을 보였다. 또한, TPH 오염 토양의 lab-scale bioremediation 실험에서 고효율 균주를 적용한 결과 45일 운전 기간 동안 7,209.9 $mg{\cdot}kg^{-1}$을 825.6 $mg{\cdot}kg^{-1}$까지 88.5% 제거하였다. 본 연구에서 도출된 TPH로 오염된 토양의 bioremediation을 위한 고효율 균주 확보와 최적의 환경 인자 도출은 현재 부족한 생물학적 처리 연구와 물리적 화학적 처리의 문제를 해소하기 위한 기초적 실험 자료로서 기여할 것으로 사료된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.161-166
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• 2002

Bioremediation of trace metals in groundwater may require the manipulation of redox conditions via the injection of a carbon source. To simulate the numerous biogeochemical processes that will occur during the bioremediation of trace-metal-contaminated aquifers, a reactive transport model has been developed. The model consists of a set of coupled mass balance equations, accounting for advection, hydrodynamic dispersion, and a kinetic formulation of the biological or chemical transformations affecting an organic substrate, electron acceptors, corresponding reduced species, and trace metal contaminants of interest, uranium in this study. The redox conditions of the domain are characterized by estimating the pE, based on the concentrations of the dominant terminal electron acceptor and its corresponding reduced specie. This pE and the concentrations of relevant species we then used by a modified version of MINTEQA2, which calculates the speciation/sorption and precipitation/dissolution of the species of interest under equilibrium conditions. Kinetics of precipitation/dissolution processes are described as being proportional to the difference between the actual and calculated equilibrium concentration.

• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.244-247
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• 2012

To remediate lead (Pb)-contaminated soils, it is proposed that microbially induced calcite precipitation (MICP) would provide the best alternative to other remediation technologies. In this study, Pb bioremediation in soils was investigated using the calcite-precipitating bacterium Kocuria flava. Results indicate that the Pb is primarily associated with the carbonate fraction in bioremediated soil samples. The bioavailability of Pb in contaminated soil was reduced so that the potential stress of Pb was alleviated. This research provides insight into the geochemistry occurring in the MICP-based Pb-remediated soils, which will help in remediation decisions.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.153-162
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• 2000

A field study was performed to test effectiveness of a bloluminescent genetically engineered microorganism (GEM) for bioremediation process monitoring and control. The study employed Pseudomonas fluorescens HK44 that was the first strain approved for field application in the U.S. for bioremediation purposes. HK44 contains lux gene fused within a naphthalene degradative pathway, allowing this GEM to bioluminesce as it degrades naphthalene as well as substituted naphthalenes and other polycyclic aromatic hydrocarbons (PAHs) , Results showed that HK44 was maintained in both PAH-contarninated and uncontaminated soils even 660 days after inoculation. HK44 was able to produce bioluminescence in response to PAHs in soil. Although effectiveness of chemical remediation was not assessed due to heterogeneous distribution of contaminants, decreased concentration of naphthalene was shown in the soils, Taken together, HK44 was useful for in situ bioremediation process monitoring and control. This work is so far the only field release of a GEM for bioremediation purposes.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.107-118
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• 2000

For the last several decades, the fate of organic pollutants has been extensively studied in natural environments with emphasis on sorption and desorption phenomena. Although the mechanisms involved are not clear yet there is a consensus about the existence of hysteresis in the sorption and desorption of organic pollutants. Furthermore, it is found that hysteresis is the outcome of slow nonequilibrium sorption of organic pollutants, which results in the formation of desorption-resistant fractions of the pollutants. Desorption-resistant fractions may increase as a function of the residence time of the pollutants in the environments. Field monitoring data show a slow but continuous decline of chemicals applied to soil, followed by little or no subsequent disappearance. One plausible explanation for such resistance to biodegradation, desorption, or extraction can be attributed the gradual movement of organic pollutants to less accessible remote sites inside the matrix with time. This phenomenon has been termed sequestration or aging. The fact that some pollutants are sequestered in soil with time may have a great impact on bioremediation and risk assessment, Some portion of the resistant pollutants may still be present in the environments after bioremediation. It requires vigorous means to completely remove the aged portion that may not be further bioavailable. However, precaution should be taken since aging is not always evident. Aging seems to be soil and chemical specific.

• Environmental Engineering Research
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• 제24권3호
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• pp.484-494
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• 2019

This paper presents a preliminary investigation of the optimum nutrients combination required for bioremediation of spent-engine oil contaminated soil using Box-Behnken-Design. Three levels of cow-manure, poultry-manure and inorganic nitrogen-phosphorus-potassium (NPK) fertilizer were used as independent biostimulants variables; while reduction in total petroleum hydrocarbon (TPH) and total soil porosity (TSP) response as dependent variables were monitored under 6-week incubation. Ex-situ data generated in assessing the degree of biodegradation in the soil were used to develop second-order quadratic regression models for both TPH and TSP. The two models were found to be highly significant and good predictors of the response fate of TPH-removal and TSP-improvement, as indicated by their coefficients of determination: $R^2=0.9982$ and $R^2=1.000$ at $p{\leq}0.05$, respectively. Validation of the models showed that there was no significant difference between the predicted and observed values of TPH-removal and TSP-improvement. Using numerical technique, the optimum values of the biostimulants required to achieve a predicted maximum TPH-removal and TSP-improvement of 67.20 and 53.42%-dry-weight per kg of the contaminated soil were as follows: cow-manure - 125.0 g, poultry-manure - 100.0 g and NPK-fertilizer - 10.5 g. The observed values at this optimum point were 66.92 and 52.65%-dry-weight as TPH-removal and TSP-improvement, respectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1843-1845
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• 2007

As the preservation law of soil environment has reinforced, several soil remediation projects have been performing for railroad sites. One of the main sources of soil contamination is the leakage of diesel from locomotives or underground storage tank. Also, the lubricant used to maintain turnouts causes railroad soil contamination. The purpose of this study was to develop the analysis and the remediation method for lubricant-contaminated soil. The lubricant in the contaminated soil was analyzed qualitatively and quantitatively by TLC (Thin Layer Chromatography) and GC (Gas Chromatography), respectively. The organic pollutants were removed from the soil using microorganisms degrading lubricant. Hereafter it will be necessary to apply this bioremediation method in the railroad field.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.164-167
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• 2004

To investigate the chemical and microbiological characteristics of groundwater and surface waters in contaminated sites, hydrochemical and microbial community analysis were executed. Different indigenous bacteria were observed at 4 contaminated sites and this is considered to decompose the contaminants of groundwater. The research results showed the close relationship between hydrochemistry and microbial characteristics and those are used for the information of natural attenuation and enhanced bioremediation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.28-30
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• 2005

Because of high population diversity in soil microbial communities, it is difficult to accurately assess the capability of biodegradation of toxicant by microbes in soil and sediment. Identifying biodegradative microorganisms is an important step in designing and analyzing soil bioremediation. To remove non-important noise information, it is necessary to selectively enrich genomes of biodegradative microorganisms fromnon-biodegradative populations. For this purpose, a stable isotope probing (SIP) technique was applied in selectively harvesting the genomes of biphenyl-utilizing bacteria from soil microbial communities. Since many biphenyl-using microorganisms are responsible for aerobic PCB degradation In soil and sediments, biphenyl-utilizing bacteria were chosen as the target organisms. In soil microcosms, 13C-biphenyl was added as a selective carbon source for biphenyl users, According to $13C-CO_2$ analysis by GC-MS, 13C-biphenyl mineralization was detected after a 7-day of incubation. The heavy portion of DNA(13C-DNA) was separated from the light portion of DNA (12C-DNA) using equilibrium density gradient ultracentrifuge. Bacterial community structure in the 13C-DNAsample was analyzed by t-RFLP (terminal restriction fragment length polymorphism) method. The t-RFLP result demonstates that the use of SIP efficiently and selectively enriched the genomes of biphenyl degrading bacteria from non-degradative microbes. Furthermore, the bacterial diversity of biphenyl degrading populations was small enough for environmental genomes tools (metagenomics and DNA microarrays) to be used to detect functional (biphenyl degradation) genes from soil microbial communities, which may provide a significant progress in assessing microbial capability of PCB bioremediation in soil and groundwater.