• 한국해양환경ㆍ에너지학회지
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• 제8권4호
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• pp.179-185
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• 2005

다환방향족 탄화수소는 주요한 독성환경오염물질풍의 하나이며 해양퇴적물에 축적이 된다. 다환방향족 탄화수소가 가지고 있는 위해성으로 인해 해양퇴적물내의 다환방향족 탄화수소 제거는 많은 관심사가 되어오고 있다. 본 연구에서는 다환방향족 탄화수소로 오염된 해양퇴적물의 생물정화를 위해 bioslurry reactor를 사용하기 위한 전단계로 ex situ bioremediation을 위한 최적 조건을 찾기 위해 멸균 유무의 퇴적물에서 균주접종과 혼합 cyclodextrin (M-CD)공급의 효과를 알아보았다. 비멸균상태의 퇴적물에서 분해균주의 접종여부에 상관없이 M-CD가 첨가된 실험구의 전자전달계활성이 증가되었고 멸균상태의 퇴적물에서는 분해균주가 접종되고 M-CD가 첨가된 실험구의 전자전달계활성이 증가되었다. 멸균상태의 퇴적물에서 M-CD와 함께 단일 균주가 접종되었을 때 퇴적물내의 다환방향족 탄화수소의 분해율이 9-20%로 나타났으며 동일한 조건에서 혼합균주가 접종되었을 때는 24-37%로 나타났다. 비멸균상태의 퇴적물에서 동일한 조건으로 실험하였을 때는 유의한 분해가 일어나지 않았으며 군집분석 결과 접종 균주도 감소하였다. 또한 M-CD 첨가 없이는 2일후 접종균주를 찾아볼 수 없었다. 결론적으로 퇴적물내의 다환방향족 탄화수소 제거를 위해 퇴적물내의 토착미생물과 포식자가 제거된 상태에서 적절한 탄소원과 함께 균주를 접종하는 것이 효과적인 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1617-1626
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• 2013

The Bacterial community structure and its complexity of the enrichment culture during the isolation and screening of imidacloprid-degrading strain were studied using denaturating gradient gel electrophoresis analysis. The dominant bacteria in the original tea rhizosphere soil were uncultured bacteria, Rhizobium sp., Sinorhizobium, Ochrobactrum sp., Alcaligenes, Bacillus sp., Bacterium, Klebsiella sp., and Ensifer adhaerens. The bacterial community structure was altered extensively and its complexity reduced during the enrichment process, and four culturable bacteria, Ochrobactrum sp., Rhizobium sp., Geobacillus stearothermophilus, and Alcaligenes faecalis, remained in the final enrichment. Only one indigenous strain, BCL-1, with imidacloprid-degrading potential, was isolated from the sixth enrichment culture. This isolate was a gram-negative rod-shaped bacterium and identified as the genus Ochrobactrum based on its morphological, physiological, and biochemical properties and its 16S rRNA gene sequence. The degradation test showed that approximately 67.67% of the imidacloprid (50 mg/l) was degraded within 48 h by strain BCL-1. The optimum conditions for degradation were a pH of 8 and $30^{\circ}C$. The simulation of imidacloprid bioremediation by strain BCL-1 in soil demonstrated that the best performance in situ (tea soil) resulted in the degradation of 92.44% of the imidacloprid (100 mg/g) within 20 days, which was better than those observed in the ex situ simulations that were 64.66% (cabbage soil), 41.15% (potato soil), and 54.15% (tomato soil).

• 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.

• 한국환경보건학회지
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• 제28권5호
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• pp.65-70
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• 2002

Recently, surfactants were frequently used in order to desorb the hydrophobic organic compounds (HOCs) from soil and to enhance the bioavailability. Among them, -cyclodextrin ($\beta$-CD) is one of those. This study was performed to investigate the binding characteristics between benzene and $\beta$-CD and to examine the bioavailability of benzene. First, we investigated binding characteristics between benzene and $\beta$-CD in water and water/soil system. Then, we examined the effect of $\beta$-CD on the biodegradation of benzene in water and water/soil system. Experimental results on the binding characteristics showed that $\beta$-CD resulted in an efficient complex formation with benzene. As -CD concentration increased, the benzene concentration complexed with $\beta$-CD rapidly increased to 30-40% initial benzene added, and reached the equilibrium. We also investigated the effect of $\beta$-CD on the desorption of benzene from soil in the water/soil system. As $\beta$-CD concentration increased, benzene concentration desorbed into water increased up to 90%. How-ever, in its application to biodegradation of benzene in water and water/soil system, the biodegradation rate of benzene did not improved in the presence of $\beta$-CD compared with in the absense of $\beta$-CD. This result indicated that $\beta$-CD was more preferentially used as a carbon source than benzene. Therefore, for remediation of benzene contaminated soils, $\beta$-CD can be used as a surfactant to desert benzene from soil, and then ex-situ chemical treatment can be applied for the remediation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.44-63
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• 2000

Situated close to Heathrow Airport, and adjacent to the M4 and M25 Motorways, the site at Axis Park is considered a prime location for business in the UK. In consequnce two of the UK's major property development companies, MEPC and Redrew Homes sought the expertise of Intergeo to remediate the contaminated former industrial site prior to its development. Industrial use of the twenty-six hectare site, started in 1936, when Hawker Aircraft commence aircraft manufacture. In 1963 the Firestone Tyre and Rubber Company purchased part of the site. Ford commenced vehicle production at the site in the mid-1970's and production was continued by Iveco Ford from 1986 to the plant's decommissioning in 1997. Geologically the site is underlain by sand and gravel, deposited in prehistory by the River Thames, with London Clay at around 6m depth. The level of groundwater fluctuates seasonally at around 2.5m depth, moving slowly southwest towards local streams and watercourses. A phased investigation of the site was undertaken, which culminated in the extensive site investigation undertaken by Intergeo in 1998. In total 50 boreholes, 90 probeholes and 60 trial pits were used to investigate the site and around 4000 solid and 1300 liquid samples were tested in the laboratory for chemical substances. The investigations identified total petroleum hydrocarbons in the soil up to 25, 000mg/kg. Diesel oil, with some lubricating oil were the main components. Volatile organic compounds were identified in the groundwater in excess of 10mg/l. Specific substances included trichloromethane, trichloromethane and tetrachloroethene. Both the oil and volatile compounds were widely spread across the site, The specific substances identified could be traced back to industrial processes used at one or other dates in the sites history Slightly elevated levels of toxic metals and polycyclic aromatic hydrocarbons were also identified locally. Prior to remediation of the site and throughout its progress, extensive liaison with the regulatory authorities and the client's professional representatives was required. In addition to meetings, numerous technical documents detailing methods and health and safety issues were required in order to comply with UK environmental and safety legislation. After initially considering a range of options to undertake remediation, the following three main techniques were selected: ex-situ bioremediation of hydrocarbon contaminated soils, skimming of free floating hydrocarbon product from the water surface at wells and excavations and air stripping of volatile organic compounds from groundwater recovered from wells. The achievements were as follows: 1) 350, 000m3 of soil was excavated and 112, 000m3 of sand and gravel was processed to remove gravel and cobble sized particles; 2) 53, 000m3 of hydrocarbon contaminated soil was bioremediated in windrows ; 3) 7000m3 of groundwater was processed by skimming to remove free floating Product; 4) 196, 000m3 of groundwater was Processed by air stripping to remove volatile organic compounds. Only 1000m3 of soil left the site for disposal in licensed waste facilities Given the costs of disposal in the UK, the selected methods represented a considerable cost saving to the Clients. All other soil was engineered back into the ground to a precise geotechnical specification. The following objective levels were achieved across the site 1) By a Risk Based Corrective Action (RBCA) methodology it was demonstrated that soil with less that 1000mg/kg total petroleum hydrocarbons did not pose a hazard to health or water resources and therefore, could remain insitu; 2) Soils destined for the residential areas of the site were remediated to 250mg/kg total petroleum hydrocarbons; in the industrial areas 500mg/kg was proven acceptable. 3) Hydrocarbons in groundwater were remediated to below the Dutch Intervegtion Level of 0.6mg/1; 4) Volatile organic compounds/BTEX group substances were reduced to below the Dutch Intervention Levels; 5) Polycyclic aromatic hydrocarbons and metals were below Inter-departmental Committee for the Redevelopment of Contaminated Land guideline levels for intended enduse. In order to verify the qualify of the work 1500 chemical test results were submitted for the purpose of validation. Quality assurance checks were undertaken by independent consultants and at an independent laboratory selected by Intergeo. Long term monitoring of water quality was undertaken for a period of one year after remediation work had been completed. Both the regulatory authorities and Clients representatives endorsed the quality of remediation now completed at the site. Subsequent to completion of the remediation work Redrew Homes constructed a prestige housing development. The properties at "Belvedere Place" retailed at premium prices. On the MEPC site the Post Office, amongst others, has located a major sorting office for the London area. Exceptionally high standards of remediation, control and documentation were a requirement for the work undertaken here.aken here.