• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.114-117
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• 2002

Sorption and desorption studies were conducted to evaluate several media as a potential biobarrier for the remediation of groundwater contaminated with hydrophobic organic compounds (HOCs). Pahokee and Bion peats, Devonian Ohio shale, vermicompost, and 50% HDTMA-montmorillonite were used as model sorbents. Sorption and desorption isotherms were determined using the radiolabeled phenanthrene (Phe). Sorption capacity of Phe on several sorbents was in the order Ohio shale > 50% HDTMA-montmorillonite > vermicompost > Pahokee peat. Mineralization kinetics was investigated for Phe-sorbed sorbents using Pseudomonas putida 17484. Among the tested sorbents, active biodegradation of Phe was observed in shale and vermicompost: degradation in shale exhibited little lag time while that in shale showed a significant lag time. Results of this study indicate that sorbents used in this work can be utilized as permeable reactive biobarrier media for the remediation of HOC-contaminated groundwater.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권6호
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• pp.11-21
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• 2022

Sorption of phenanthrene (PHE) and pyrene (PYR) in several sorbents, i.e., natural soil, BionSoil^®, Pahokee peat, vermicompost and Devonian Ohio Shale and a surfactant (hexadecyltrimethyl ammonium chloride)-modified montmorillonite (HDTMA-M) were investigated. Pyrene exhibited higher sorption tendency than phenanthrene, as predicted by its higher octanol to water partition coefficient (K_ow). Several sorption models: linear, Freundlich, solubility-normalized Freundlich model, and Polanyi-Manes model (PMM) were used to analyze sorption isotherms. Linear isotherms were observed for natural soil, BionSoil^®, Pahokee peat, vermicompost, while nonlinear Freundlich isotherms fitted for Ohio shale and HDTMA-M. The relationship between sorption model parameters, organic carbon content (f_oc), and elemental C/N ratio was studied. In the binary competitive sorption of phenanthrene and pyrene in natural soil, competition between the solutes caused reduction in the sorption of each solute compared with that in the single-solute system. The ideal adsorbed solution theory (IAST) coupled with the single-solute Freundlich model was not successful in describing the binary competitive sorption equilibria. This was due to the inherent nature of linear sorption of phenanthrene and pyrene in natural soil. The result indicates that the applicability of IAST for the prediction of binary competitive sorption is limited when the sorption isotherms are inherently linear.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.92-95
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• 2002

Bioavailability study was conducted to elucidate the relationship between sorption/desorption and biodegradation of sorbed phenanthrene in seven different soils. Mineralization kinetics was determined for phenanthrene-sorbed soil slurries inoculated with Pseudomonas putida (ATCC strain 17484). Two biodegradation models were used to fit mineralization kinetics; (i) a first-order degradation model and (ii) a coupled degradation-desorption model. The biodegradation rates were in order of vermicompost >Bion peat > 50% organoclay > Pahokee > blank (no soil, medium only) > montmorillonite > Ohio shale. The mineralization rate constants increased as desorption-resistance of phenanthrene increased. Among the tested sorbents, active biodegradation of phenanthrene was observed in vermicompost and Bion peat. Biodegradation in these two sorbents exhibited little lag time and a high maximum mineralized capacity. The role of sorption/desorption in bioavailability of phenanthrene sorbed in soils was discussed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.391-394
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• 2003

The applicability of in situ microbial filter or biobarrier technology for the remediation of soil and groundwater contaminated with chlorinated solvents was investigated. The efficiency and rates of reductive dechlorination of chlorinated solvents are known to be highly dependent on hydrogen concentration. In this study, the effect of electron donors on the reductive dechlorination of PCE was investigated using vermicompost (worm casting) and peat as permeable reactive barrier medium The effect of organic acids (lactate, butyrate and benzoate), yeast extract and vitamin $B_{l2}$ on the reductive dechlorination was investigated. Compared to the control (no electron donor added), addition of electron donors stimulated the dechlorinated rate. Among the electron donor treatments, lactate/benzoate amendment exhibited the highest dechlorination rate. Since vermicompost and peat are inexpensive and biodegradable and have high sorption capacity, they could be successfully used as biobarrier media, especially when electron donors (for example, lactate/benzoate) are added.d.

• 한국환경과학회지
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• 제16권10호
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• pp.1147-1155
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• 2007

The applicability of in situ biobarrier or microbial filter technology for the remediation of groundwater contaminated with chlorinated solvent was investigated through column study. In this study, the effect of packing materials on the reductive dechlorination of PCE was investigated using Canadian peat, Pahokee peat, peat moss and vermicompost (or worm casting) as a biobarrier medium. Optimal conditions previously determined from a batch microcosm study was applied in this column study. Lactate/benzoate was amended as electron donors to stimulate reductive dechlorination of PCE. Hydraulic conductivity was approximately $6{\times}10^{-5}-8{\times}10^{-5}\;cm/sec$ and no difference was found among the packing materials. The transport and dispersion coefficients determined from the curve-fitting of the breakthrough curves of $Br^-$ using CXTFIT 2.1 showed no difference between single-region and two-region models. The reductive dechlorination of PCE was efficiently occurred in all columns. Among the columns, especially the column packed with vermicompost exhibited the highest reductive dechlorination efficiency. The results of this study showed the promising potential of in situ biobarrier technology using peat and vermicompost for the remediation of groundwater contaminated with chlorinated solvents.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권2호
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• pp.22-37
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• 2006

생물벽체(biobarrier) 또는 원위치 미생물 필터(in situ microbial filter) 기술을 이용한 염소계 유기용매로 오염된 지하수의 복원 가능성을 회분식 실험을 통하여 살펴보았다. PCE의 환원성 탈염소화의 효율과 속도는 수소 농도에 의존하는 것으로 알려져 있다. 본 연구에서는 분변토와 토탄을 생물벽체로 이용한 PCE의 환원성 탈염소화시 전자공여체의 영향을 살펴보았다. 유기산(lactate, butyrate benzoate)과 yeast extract, 비타민 $B_{12}$가 PCE의 환원성 탈염소화에 미치는 영향을 조사하였다. 생물벽체 담체 비존재시, 전자공여체를 투여하지 않은 control 실험에 비해, 전자공여체의 첨가는 PCE의 탈염소화 속도를 촉진하였다. 전자공여체를 투여한 실험 중에서 lactate 또는 lactate/benzoate를 수소 공여체(hydrogen donor)로 첨가된 경우, 탈염소화 속도가 가장 빨랐다($k_1=0.0260{\sim}0.0266\;day^{-1}$). 분변토를 생물벽체로 사용한 경우, lactate/benzoate 첨가시 탈염소화 속도가 가장 빨랐으며, 겉보기 1차 분해속도상수($k_1$)는 $0.0849day^{-1}$였다. 반면, Pahokee peat을 생물벽체로 사용하였을 경우, butyrate 또는 lactate의 첨가시 탈염소화 속도가 가장 빨랐으며 $k_1$ 값은 각각 0.1092, $0.1067\;day^{-1}$로 나타났다. 본 연구결과로부터 분변토 또는 토탄을 원위치 생물벽체로 사용하여 염소계 유기용매로 오염된 지하수 처리의 잠재적인 응용 가능성을 알 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권6호
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• pp.47-57
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• 2022

A number of different methods have been used for modeling the sorption of volatile organic chlorinated compounds such as tetrachloroethylene/perchloroethylene (PCE). In this study, PCE was adsorbed in several natural sorbents, i.e., Pahokee peat, vermicompost, BionSoil^®, and natural soil, in the batch experiments. Several sorption models such as linear, Freundlich, solubility-normalized Freundlich model, and Polanyi-Manes model (PMM) were used to analyze sorption isotherms. The relationship between sorption model parameters, organic carbon content (f_oc), and elemental C/N ratio was studied. The organic carbon normalized partition coefficient values (log K_oc = 1.50-3.13) in four different sorbents were less than the logarithm of the octanol-water partition coefficient (log K_ow = 3.40) of PCE due to high organic carbon contents. The log K_oc decreased linearly with log f_oc and log C/N ratio, but increased linearly with log O/C, log H/C, and log (N+O)/C ratio. Both log K_F,oc or log K_F,oc decreased linearly with log f_oc (R² = 0.88-0.92) and log C/N ratio (R² = 0.57-0.76), but increased linearly with log (N+O)/C (R² = 0.93-0.95). The log q_max,oc decreased linearly as log f_oc and log C/N increased, whereas it increased with log O/C, log H/C and log (N+O)/C ratios. The log q_max,oc increased linearly with (N+O)/C indicating a strong dependence of q_max,oc on the polarity index. The results showed that PCE sorption behaviors were strongly correlated with the physicochemical properties of soil organic matter (SOM).