본 연구에서는 방사성동위원소 추적자 실험을 통해서 산화아연 또는 두 종류의 은나노물질로 오염시킨 토양에서 지렁이 (Eisenia fetida)의 금속축적과 제거율을 비교하였고, 이들을 이온상의 Ag와 Zn으로 처리한 대조구와 비교하였다. 추가적으로 토양의 금속을 다단계추출법 (sequential extraction method)을 이용하여 금속의 결합 형태로부터 생물이용도 (bioavailability)를 예측하고 실제 생물축적 (BAF, bioaccumulation factor)과 비교하였다. ZnO 처리구의 BAF (0.06)는 아연이온 처리구 BAF (1.86)보다 31배 낮았는데, 이는 토양에서 ZnO의 생물전이가 매우 낮음을 제시해 준다. 한편, 은의 BAF는 금속의 오염 형태에에 무관 하게 0.11~0.17의 범위를 보였다. 다단계추출법을 통해서 아연이온 처리구의 아연은 토양에 비교적 약한 결합을 하 는 형태 (mobile fraction)에 35% 분포하여 아연이온처리구 값 (<20%)보다 높았고, 이는 전자의 더 높은 BAF와 일치 한다. 하지만, ZnO 처리구의 다단계추출은 생물이용도나 BAF를 잘 예측하지 못했으며 이는 ZnO가 토양에서 아연 이온과 지화학적으로 다른 거동을 하기 때문으로 추정된다. 지렁이 체내에 축적된 은의 제거율 (3.2~3.8% d-1)은 아연의 제거율 (1.2~1.7% d-1)보다 2~3배 더 높았다

Petroleum energy is the major source of the world energy market, and its massive usage, and the corresponding extreme environmental pollution, imposes a serious threat on the ecological cycles. By screening oil-contaminated soil, we isolated, identified, and characterized a novel strain that represents a considerable diesel-degrading potentiality; the Bacillus aryabhattai DA2 strain is registered in the NCBI with the accession number MG571630, and it possesses an efficient tributyrin-degrading capacity. The optimal condition for diesel degradation by DA2 strain was observed at pH between 7-8 and at the temperature of 30°C. The strain is resistant to salt as well as the antibiotics like ampicillin and streptomycin. These results indicate B. aryabhattai is one of the potential candidates for the remediation of the diesel-contaminated sites.

The petroleum industry is an important part of the world economy. However, the massive exposure of petroleum in nature is a major cause of environmental pollution. Therefore, the microbial mediated biodegradation of petroleum residues is an emerging scientific approach used to resolve these problem. Through the screening of diesel contaminated soil we isolated a rapid phenanthrene and a diesel degrading bacterium identified as Enterobacter cancerogenus DA1 strain through 16S rRNA gene sequence analysis. The strain was registered in NCBI with an accession number MG270576. The optimal growth condition of the DA1 strain was determined at pH 8 and 35°C, and the highest degradation rate of the diesel was achieved at this condition. At the optimal condition, growth of the strain on the medium containing 0.05% phenanthrene and 0.1% of diesel-fuel was highest at 45 h and 60 h respectively after the incubation period. Biofilm formation was found significantly higher at 35°C as compared to 30°C and 40°C. Likewise, the lipase activity was found significantly higher at 48 h after the incubation compared to 24 h and 72 h. These results suggest that the Enterobacter cancerogenus DA1 could be an efficient candidate, for application through ecofriendly scientific approach, for the biodegradation of petroleum products like diesel.

본 연구는 실제 유류오염토양을 in situ 토양세정법으로 정화시 기술 적용성을 평가하기 위한 회분식 기초연구로 적정 계면활성제의 종류와 농도를 결정하고자 하였다. 증류수만의 진탕효과로 인한 TPH 제거는 약 30%이었으며, 계면활성제 희석시 사용되는 용액으로는 증류수를 사용한 경우에 비하여 지하수(해수 혼합)의 유입으로 인하여 약 2~6%의 효율저하가 나타났다. 토양과 계면활성제 용액비는 회분식 실험에서 TPH 제거효율에 미치는 영향이 미미하였다. 단독 또는 혼합 계면활성제 농도를 0.1~4.0 wt%까지 변화시켜 세정한 결과 종류별로는 Tween-80, SWA-1503, SWA-1503+SDS에서 평 균 제거율이 80% 이상으로 대체적으로 높은 효율을 보였으며, 농도에 따른 차이는 크지 않아 0.1 wt% 농도를 최적 농도로 판단하였다.

본 연구에서는 중금속 오염토양 및 광미의 고형화 처리를 위한 보통 포틀랜드 시멘트의 혼화재로서 제강슬래그의 처리효과를 검토하였다. 대상시료는 충청남도 청양군 남양면 구룡리의 구봉광산 주변 하천퇴적토와 강원도 영월군 상동읍 내덕리의 상동광산에 위치한 광미를 채취하여 사용하였다. 경화제는 시멘트 95%에 제강슬래그 분말 5%를 혼합하여 제조하였으며, 하천퇴적토 및 광미오염토양에 5%, 10% 및 15%(w/w)의 경화제를 첨가하였다. 이때 이 결과들은 시멘트만을 사용한 것과 Ca 함량이 제강슬래그 보다 상대적으로 높은 굴폐각 분말을 사용하여 배합한 결과와 함께 비교하였다. 공시체는 지름 5cm, 높이 10 cm의 몰드를 이용하여 혼합토를 채워 넣은 후, 습윤양생기에서 1일간 양생시킨 다음 탈형 후, 수조에 수중양생을 실시하였다. 7일, 14일 및 28일 경과된 시료를 대상으로 강도시험 및 중금속 용출시험을 실시하여 처리효과를 비교·검토하였다. 광미시료의 경우, 시멘트, 제강슬래그 그리고 굴폐각 순으로 강도 개선의 효과가 큰 것으로 나타나 제강슬래그의 효과를 확인할 수 없었고, 하천퇴적토의 경우는 혼합비 15%에서 제강슬래그를 혼합한 경우에서 우수한 효과를 나타내 혼화재로서 적용을 기대할 수 있을 것으로 판단되었다. 폐기물용출시험 및 0.1 N 염산추출법 결과 경화제의 혼합비가 증가할수록 중금속 및 비소의 농도가 감소하는 경향이 나타났고 특히 비소에 있어서는 제강슬래그의 효과가 가장 좋게 나타났다. 산도가 가장 높은 1N 염산추출법의 결과에서는 광미의 경우 대조구 보다 제강슬래그로 처리한 시료에서 중금속 및 비소의 농도가 아주 낮게 나타났다. 그러나 하천퇴적토는 대조구와 큰 차이가 없이 중금속 및 비소가 용출되었다. 이는 하천퇴적토가 95%이상의 모래로 토양의 입경이 크기 때문에 상대적으로 중금속의 고정화율이 상대적으로 낮은 것으로 판단되었다.

본 연구는 TNT 오염토양을 콤포스팅과 슬러리생물상으로 처리 후 형광미생물을 이용하여 독성을 평가하고자 실시되었으며, 운전기간은 각각 45일과 200일이었다. 콤포스팅 처리 후 C/N비 조절용으로 아세톤을 첨가한 경우의 GL값은 40으로 글루코오스를 첨가한 경우(GL 80)보다 낮아 독성이 더 많이 제거되었다. 혐기성, 혐기성/호기성, 그리고 호기성 조건의 슬러리생물상으로 처리 후 GL값은 각각 6, 8, 4로 나타나 독성이 거의 없는 수준까지 크게 감소하였다. GL값과 S. typhimurium 수의 상관도는 1차식으로 표현이 가능하였으며, 생물학적 처리에 따른 미생물독성과 돌연변이성 변화는 비교적 높은 상관도 (r > 0.8890)를 나타내었다.

This study was decontaminant to use hydrogen peroxide(H2O2), surfactant and microbial and to use field contaminated soil experiment was to evaluate the adequacy and processing possibilities. A chemical oxidation was applied to using 5% concentration hydrogen peroxide more than 75% removal efficiency for TPH. Surfactant result of using SOR-100 1% 5,066 mg/kg to 796 mg/kg as the highest efficiency. Microbial injected 106 CFU/g soil in the soil by 45 days result of low-contaminated soil 1,325 mg/kg, removal rate was 57.7%.

We have accomplished a various reaction experiment for a purifying agent selection which is related with efficient site demobilization about soil contaminated with the total petroleum hydrocarbon(TPH) in link of contaminated soil purification enterprise of power train center in Y railway car places of business for an oxidizer comparison experiment, we have differed consistency and implantation quantity of the hydrogen peroxide (H2O2). The result showed the highest 98.8% removal ratio, when H2O2 is 35% consistency. In the same way, the result which implants at 1:1 ratio (hydrogen peroxide (H2O2) : the catalyst (FeSO4 ․7H2O)) showed a similar result, when only the hydrogen peroxide was implanted.

Trophic groups and functional guilds were studied of soil nematodes from the soils of two abandoned mines in Ilkwang and Gunbuk, South Korea to compare nematode communities between the heavy metal contaminated soil and the nonheavy metal contaminated soil. No obvious correlation was found between the level of heavy metal and the total number of nematodes statistically. However the overall densities of bacterial, hyphal, omnivorous and predatory nematodes from the non-heavy metal contaminated soil was higher than those from the heavy metal contaminated soil. Also the densities of c-p 2, c-p 3, c-p 4 and c-p 5 nematodes were higher from the non-heavy metal contaminated soil than those from the heavy metal contaminated soil. MI, MI 2-5 and ΣMI 2-5 were higher, but there were no significant differences.

This paper presents applicability of Fenton oxidation to perchloroethylene(PCE) contaminated soil. The initial concentration of PCE was 187mg/kg and Fenton oxidation conditions were 1.0M H2O2 and 0.5M Fe2+. More than 97% of PCE decomposition and 98% of dechlorination were obtained within 5 hrs. It was found that the decomposition of PCE by Fenton oxidation was followed pseudo first order and its reaction coefficient was 0.78 hr-1. GC-MS and GC-ECD analysis of reaction intermediates confirmed only the presence of trichloroacetic acid(i.e., 1.0% of initial PCE concentration). Under Fenton oxidation conditions, it was proposed that PCE was decomposed not simultaneously but one by one.

Ethanol washing with distillation as a cleanup process of polycyclic aromatic hydrocarbon(PAH)-contaminated soil was investigated in this study. A multistage ethanol washing with distillation process was applied to three different types of soil, i.e., sandy soil, alluvial soil, and clay with the initial concentration of benzo(a)pyrene 10 mg/kg, benz(a)anthracene 250 mg/kg, and pyrene 100 mg/kg soil. Ethanol was selected as washing solvent because of its high PAH removal efficiency, low cost, and non-toxicity comparing to the other solvent such as isopropyl alcohol and sodium dodecyl sulfate. The satisfactory results (i.e. lower than benzo(a)pyrene 1 mg/kg, pyrene 10 mg/kg, benz(a)anthracene 25 mg/kg, which are the Canada or the Netherlands soil standard) for three types of soils were obtained by at most five-six times washing. It was suggested that organic content in soil decreased the removal efficiency by ethanol washing.

본 연구는 아연폐광지역의 토양에 토양개량제를 처리한 후 구절초와 층꽃나무의 생장반응을 연구함으로서 생태계 복원을 위한 기초자료를 얻고자 실시하였다. 아연폐광지의 토양은 유기물 함량ㅇ이 낮았고, 토양 중 중금속 이온은 Zn의 함량이 가장 높았고 Pb, Cu, Cd순이었다. 아연폐광지역 토양에 슬러지 처리 시 유기물 함량이 가장 높았고, 중금속 이온 함량은 토양개량제 초리구간의 차이가 적었다. 생육반응을 보면 구정초와 층꽃나무 모두 슬러지 처리구의 효과가 나타났다. 구절초와 층꽃나무의 가용성 단백질, 엽록소 함량, 엽록소 형광 반응은 슬러지 처리구에서 가장 높았고, 광함성량과 증산량도 슬러지 처리구에서 높았다. 중금속 축적량은 구절초는 슬러지 처리구에서 낮았던 반면 층꽃나무는 슬러지 처리구에서 높았다.

Uranium-contaminated soil can be cleaned using an acid washing process. However, high-concentration acid washing generates substantial amounts of radioactive waste, making it essential to develop a treatment process using low-concentration acid. This study evaluated the effectiveness of low-concentration sulfuric acid washing for uranium removal from contaminated soil. Experiments were conducted with a 0.05 M sulfuric acid solution. With a mixing ratio of soil to acid solution at 1:5, three consecutive washes were sufficient to remove uranium from contaminated soil to clearance level. During the acid washing process, real-time pH monitoring was performed to analyze the correlation between uranium leaching and pH changes. This led to the establishment of a monitoring-based process control strategy. In conclusion, we identified an effective method for removing uranium from soil under low acid concentration conditions. Consequently, significant reductions in radioactive waste generation are anticipated.

This study aimed to develop an efficient recycling process for wastewater generated from soil-washing used to remediate uranium (U(VI))-contaminated soil. Under acidic conditions, U(VI) ions leached from the soil were precipitated and separated through neutralization using hydrazine (N2H4). N2H4, employed as a pH adjuster, was decomposed into nitrogen gas (N2), water (H2O), and hydrogen ions (H+) by hydrogen peroxide (H2O2). The residual N2H4 was precipitated when the pH was adjusted using sulfuric acid (H2SO4) to recycle the wastewater in the soil-washing process. This purified wastewater was reused in the soil-washing process for a total of ten cycles. The results confirmed that the soil-washing performance for U(VI)-contaminated soil was maintained when using recycled wastewater. All in all, this study proposes an efficient recycling process for wastewater generated during the remediation of U(VI)-contaminated soil.

When decommissioning a nuclear power plant, it is expected that clearance or radioactive waste (e.g., soil, concrete, metal, etc.) below the low-level will be generated in a short period on a large scale. Among the various types of waste, most of the contaminated soil is known to be classified as clearance or the (very) low-level radioactive waste. Accordingly, an accurate measurement and classification of contaminated soil in real-time during the decommissioning process can efficiently reduce the amount of soil waste and the possibility of contamination diffusion. However, in order to apply a system that measures and classifies contaminated soil in real-time according to the level of contamination to the decommissioning site, a demonstration is required to evaluate whether the system is applicable to the site. In this study, to establish requirements for determining the applicability of the system to the decommissioning site, preceding cases from countries with abundant decommissioning experience were investigated. For example, MACTEC of the U.S. demonstrated the developed system at the Saxton nuclear power plant in the U.S. and confirmed that the amount of soil that can be analyzed per hour in the system is affected by radionuclides, minimum detectable activity (MDA), and applicable volume. In the future, therefore, we will utilize the result of this study to develop the requirements of demonstrating the system for measurement and classification of contaminated soil in real-time.

For the release of the nuclear power plant site after the decommissioning, a reliable exposure dose assessment considering the environmental impact of residual radionuclides is essentially required. In this study, the Derived Concentration Guideline Level (DCGL) for the hypothetically contaminated surface soil at the Wolsong nuclear power plant (NPP) unit 1 site was preliminarily calculated by using the RESRAD-OFFSITE computational code and compared with the other case studies. Moreover, radiation exposure dose for local residents and relevant exposure pathways were quantitatively analyzed based on the calculation model established through this work. For the target site modeling, the source term was determined by referring to the previous case studies regarding the nuclear power plant decommissioning, quantification analysis data of pressure tubes of Wolsong NPP unit 1, and radionuclide data estimated by using the MCNP/ORIGEN-2 code. In total, 14 different radioisotopes such as Ag-108m, C-14, Co-60, Cs-134/137, Fe-55, H-3, Nb-93m/94, Ni-63, Sb-125, Sn-121m, Sr-90, and Zr-93 were considered as target radionuclides. In addition, the geological structure model of the Wolsong NPP site was established based on the final safety analysis report of Wolsong NPP unit 1. The distribution coefficients (Kd) were taken from the JAEA-SDB to estimate the migration/retardation behavior of various radionuclides under the groundwater condition of the Wolsong NPP site. In the present work, the DCGL values were calculated according to the site release criterion of 0.1 mSv/yr, which indicates the radiation protection standard for the site release. Moreover, the exposure pathway and sensitivity analyses were conducted to assess the sensitive input parameters remarkably influencing the calculation result. For the evaluation of exposure dose for local residents, a site layout centered around Wolsong NPP unit 4, located in the closest proximity to the residents’ habitation area, was alternatively established and all potential exposure pathways were considered as a comprehensive resident farmer scenario. The results obtained from this study are expected to serve as a preliminary case study for the DCGL values regarding the surface soil at the Wolsong NPP unit 1 site and for evaluating the radiation exposure dose to local residents resulting from the residual radioactivity at the site after the decommissioning.

Economical radioactive soil treatment technology is essential to safely and efficiently treat of high-concentration radioactive areas and contaminated sites during operation of nuclear power plants at home and abroad. This study is to determine the performance of BERAD (Beautiful Environmental construction’s RAdioactive soil Decontamination system) before applying magnetic nanoparticles and adsorbents developed by the KAERI (Korea Atomic Energy Research Institute) which will be used in the national funded project to a large-capacity radioactive soil decontamination system. BERAD uses Soil Washing Process by US EPA (402-R-007-004 (2007)) and can decontaminate 0.5 tons of radioactive soil per hour through water washing and/or chemical washing with particle size separation. When contaminated soil is input to BERAD, the soil is selected and washed, and after going through a rinse stage and particle size separation stage, it discharges decontaminated soil separated by sludge of less than 0.075 mm. In this experiment, the concentrations of four general isotopes (A, B, C, and D which are important radioisotopes when soil is contaminated by them.) were analyzed by using ICP-MS to compare before and after decontamination by BERAD. Since BERAD is the commercial-scale pilot system that decontaminates relatively large amount of soil, so it is difficult to test using radioactive isotopes. So important general elements such as A, B, C, and D in soil were analyzed. In the study, BERAD decontaminated soil by using water washing. And the particle size of soil was divided into a total of six particle size sections with five sieves: 4 mm, 2 mm, 0.850 mm, 0.212 mm, and 0.075 mm. Concentrations of A, B, C, and D in the soil particles larger than 4 mm are almost the lowest regardless of before and after decontamination by BERAD. For soil particles less than 4 mm, the concentrations of C and D decreased constantly after BERAD decontamination. On the other hand, the decontamination efficiency of A and B decreased as the soil particle became smaller, but the concentrations of A and B increased for the soil particle below 0.075 mm. As a result, decontamination efficiency of one cycle using BERAD for all nuclides in soil particles between 4 mm and 0.075 mm is about 45% to 65 %.

The primary objective of this study is to evaluate a systematic design’s effectivity in remediating actual uranium-contaminated soil. The emphasis was placed on practical and engineering aspects, particularly in assessing the capabilities of a zero liquid discharge system in treating wastewater derived from soil washing. The research method involved a purification procedure for both the uranium-contaminated soil and its accompanying wastewater. Notably, the experimental outcomes demonstrated successful uranium separation from the contaminated soil. The treated soil could be self-disposed of, as its uranium concentration fell below 1.0 Bq·g−1, a level endorsed by the International Atomic Energy Agency for radionuclide clearance. The zero liquid discharge system’s significance lay in its distillation process, which not only facilitated the reuse of water from the separated filtrate but also allowed for the self-disposal of high-purity Na2SO4 within the residues of the distilled filtrate. Through a comparative economic analysis involving direct disposal and the application of a remediation process for uranium-contaminated soil, the comprehensive zero liquid discharge system emerged as a practical and viable choice. The successful demonstration of the design and practicality of the proposed zero liquid discharge system for treating wastewater originating from real uranium-contaminated soil is poised to have a lasting impact.