Pub Date : 1998-09-01DOI: 10.1080/10588339891334474
D. White, R. Irvine
The purpose of this research was to investigate the feasibility of suction bioventing for treatment of contaminated tundra soil. Two laboratory-scale venting reactors were prepared with tundra from Arctic Alaska and operated, one for 32 d and the other for 52 d. For each rectangular reactor, suction was applied to a central well screened at mid-depth, while opposite ends of the reactor were screened to serve as air intake zones. The volume of liquid and gas recovered from the suction well was quantified daily. Numbers for heterotrophic organisms, pH, and dissolved organic carbon were quantified in the recovered liquid. The suction pump held a full vacuum (i.e., 101 kPa vac) for the duration of both experiments, indicating continuous obstruction of pneumatic and hydraulic conductivity. In both reactors, the soil in the proximity of the suction well separated from the bulk of the soil, precluding hydraulic communication. Furthermore, the soil nearest the well screen compacted, forming a barrier to appreciab...
{"title":"Bioventing in Shallow Tundra Overlying Permafrost","authors":"D. White, R. Irvine","doi":"10.1080/10588339891334474","DOIUrl":"https://doi.org/10.1080/10588339891334474","url":null,"abstract":"The purpose of this research was to investigate the feasibility of suction bioventing for treatment of contaminated tundra soil. Two laboratory-scale venting reactors were prepared with tundra from Arctic Alaska and operated, one for 32 d and the other for 52 d. For each rectangular reactor, suction was applied to a central well screened at mid-depth, while opposite ends of the reactor were screened to serve as air intake zones. The volume of liquid and gas recovered from the suction well was quantified daily. Numbers for heterotrophic organisms, pH, and dissolved organic carbon were quantified in the recovered liquid. The suction pump held a full vacuum (i.e., 101 kPa vac) for the duration of both experiments, indicating continuous obstruction of pneumatic and hydraulic conductivity. In both reactors, the soil in the proximity of the suction well separated from the bulk of the soil, precluding hydraulic communication. Furthermore, the soil nearest the well screen compacted, forming a barrier to appreciab...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"15 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114129042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334401
S. Pradhan, J. Conrad, J. Paterek, V. Srivastava
Phytoremediation is a natural, aesthetically pleasing, low-cost technology that employs plant-influenced microbial, chemical, and physical processes to remediate contaminated soils and waters. The Institute of Gas Technology (IGT) conducted a laboratory study to determine the potential of phytoremediation to remediate soils contaminated with polynuclear aromatic hydrocarbons (PAHs). The soils used for the study were collected from a former manufactured gas plant (MGP) site in Newark, NJ. Phytoremediation was assessed both as a primary remediation technology and as a final polishing step for soil treatment. The following three plant species were used for the 6-month laboratory study: alfalfa (Medicago sativa), switch grass (Panicum virgatum), and little bluestem grass (Schizachyrium scoparium). Using both alfalfa and switch grass for primary treatment of PAH-contaminated soil, a 57% reduction in total PAH concentration was observed after 6-months of treatment. Final polishing of that soil using alfalfa fur...
{"title":"Potential of Phytoremediation for Treatment of PAHs in Soil at MGP Sites","authors":"S. Pradhan, J. Conrad, J. Paterek, V. Srivastava","doi":"10.1080/10588339891334401","DOIUrl":"https://doi.org/10.1080/10588339891334401","url":null,"abstract":"Phytoremediation is a natural, aesthetically pleasing, low-cost technology that employs plant-influenced microbial, chemical, and physical processes to remediate contaminated soils and waters. The Institute of Gas Technology (IGT) conducted a laboratory study to determine the potential of phytoremediation to remediate soils contaminated with polynuclear aromatic hydrocarbons (PAHs). The soils used for the study were collected from a former manufactured gas plant (MGP) site in Newark, NJ. Phytoremediation was assessed both as a primary remediation technology and as a final polishing step for soil treatment. The following three plant species were used for the 6-month laboratory study: alfalfa (Medicago sativa), switch grass (Panicum virgatum), and little bluestem grass (Schizachyrium scoparium). Using both alfalfa and switch grass for primary treatment of PAH-contaminated soil, a 57% reduction in total PAH concentration was observed after 6-months of treatment. Final polishing of that soil using alfalfa fur...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124831531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334366
L. Newman, S. Doty, Katrina L. Gery, P. Heilman, I. Muiznieks, T. Q. Shang, Sarah T. Siemieniec, S. Strand, Xiaoping Wang, Angela M Wilson, M. Gordon
As overwhelmingly positive results have become available regarding the ability of plants to degrade compounds such as trichloroethylene, phytoremediation studies are expanding. Studies to determine the potential for phytoremediation of fully chlorinated compounds, such as carbon tetrachloride and tetrachloroethylene, brominated compounds, such as ethylene dibromide and dibromochloropropane, and nonhalogenated compounds, such as methyl-t-butyl ether (MTBE), are underway. When using phytoremediation, it is important to select not only a plant that is capable of degrading the pollutant in question, but also one that will grow well in that specific environment. In ecologically sensitive areas, such as the Hawaiian Islands, only plants native to the area can be used. One way to supplement the arsenal of plants available for remedial actions is to utilize genetic engineering tools to insert into plants those genes that will enable the plant to metabolize a particular pollutant. Hybrid technologies, such as usin...
{"title":"Phytoremediation of Organic Contaminants: A Review of Phytoremediation Research at the University of Washington","authors":"L. Newman, S. Doty, Katrina L. Gery, P. Heilman, I. Muiznieks, T. Q. Shang, Sarah T. Siemieniec, S. Strand, Xiaoping Wang, Angela M Wilson, M. Gordon","doi":"10.1080/10588339891334366","DOIUrl":"https://doi.org/10.1080/10588339891334366","url":null,"abstract":"As overwhelmingly positive results have become available regarding the ability of plants to degrade compounds such as trichloroethylene, phytoremediation studies are expanding. Studies to determine the potential for phytoremediation of fully chlorinated compounds, such as carbon tetrachloride and tetrachloroethylene, brominated compounds, such as ethylene dibromide and dibromochloropropane, and nonhalogenated compounds, such as methyl-t-butyl ether (MTBE), are underway. When using phytoremediation, it is important to select not only a plant that is capable of degrading the pollutant in question, but also one that will grow well in that specific environment. In ecologically sensitive areas, such as the Hawaiian Islands, only plants native to the area can be used. One way to supplement the arsenal of plants available for remedial actions is to utilize genetic engineering tools to insert into plants those genes that will enable the plant to metabolize a particular pollutant. Hybrid technologies, such as usin...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128712679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334429
R. Brigmon, N. C. Bell, D. Freedman, C. Berry
Extensive trichloroethylene (TCE) groundwater contamination has resulted from discharges to a former seepage basin in the A/M Area at the Department of Energy's Savannah River Site. The direction of groundwater flow has been determined and a seep line where the contaminated groundwater is estimated to emerge as surface water has been identified in a region of the Southern Sector of the A/M Area. This study was undertaken to estimate the potential of four rhizosphere soils along the seep line to naturally attenuate TCE. Microcosms were setup to evaluate both biotic and abiotic attenuation of TCE. Results demonstrated that sorption to soil was the dominant mechanism during the first week of incubation, with as much as 90% of the TCE removed from the aqueous phase. Linear partitioning coefficients (Kd) ranged from 0.83 to 7.4 mL/g, while organic carbon partition coefficients (Koc) ranged from 72 to 180 mL/gC. Diffu-sional losses from the microcosms appeared to be a dominant fate mechanism during the remainde...
{"title":"Natural Attenuation of Trichloroethylene in Rhizosphere Soils at the Savannah River Site","authors":"R. Brigmon, N. C. Bell, D. Freedman, C. Berry","doi":"10.1080/10588339891334429","DOIUrl":"https://doi.org/10.1080/10588339891334429","url":null,"abstract":"Extensive trichloroethylene (TCE) groundwater contamination has resulted from discharges to a former seepage basin in the A/M Area at the Department of Energy's Savannah River Site. The direction of groundwater flow has been determined and a seep line where the contaminated groundwater is estimated to emerge as surface water has been identified in a region of the Southern Sector of the A/M Area. This study was undertaken to estimate the potential of four rhizosphere soils along the seep line to naturally attenuate TCE. Microcosms were setup to evaluate both biotic and abiotic attenuation of TCE. Results demonstrated that sorption to soil was the dominant mechanism during the first week of incubation, with as much as 90% of the TCE removed from the aqueous phase. Linear partitioning coefficients (Kd) ranged from 0.83 to 7.4 mL/g, while organic carbon partition coefficients (Koc) ranged from 72 to 180 mL/gC. Diffu-sional losses from the microcosms appeared to be a dominant fate mechanism during the remainde...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133739819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334438
P. Flathman, G. Lanza
{"title":"PHYTOREMEDIATION: CURRENT VIEWS ON AN EMERGING GREEN TECHNOLOGY","authors":"P. Flathman, G. Lanza","doi":"10.1080/10588339891334438","DOIUrl":"https://doi.org/10.1080/10588339891334438","url":null,"abstract":"","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128210427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334393
G. Bañuelos, H. Ajwa, Lin Wu, S. Zambrzuski
Selenium (Se) may be present in soils and sediments in high concentrations and yet not be mobile or available for plant uptake. Phytoremediation of Se by canola (Brassica napus) was evaluated in sediment from Kesterson Reservoir at three different depths (0 to 30, 30 to 60, 60 to 90 cm) under greenhouse and field conditions. In the greenhouse study, total soil Se concentrations at preplant ranged from 10 to 112 mg kg−1. Shoot Se concentrations of canola were 182, 53, and 19 mg kg−1 DM in the 0 to 30, 30 to 60, and 60 to 90 cm depths, respectively. Percentages of Se accumulated by canola relative to total Se loss in the soil at postharvest were as high as 24%. In the field study, total soil Se concentrations were as high as 26 mg kg−1 soil. Field-grown canola accumulated approximately 50 mg kg−1 DM, which accounted for less than 10% of total Se lost in the soil at postharvest. Phytoremediation of Se-laden soils under field conditions was about 50% of that observed under controlled greenhouse conditions. Th...
{"title":"Selenium Accumulation by Brassica Napus Grown in Se-Laden Soil From Different Depths of Kesterson Reservoir","authors":"G. Bañuelos, H. Ajwa, Lin Wu, S. Zambrzuski","doi":"10.1080/10588339891334393","DOIUrl":"https://doi.org/10.1080/10588339891334393","url":null,"abstract":"Selenium (Se) may be present in soils and sediments in high concentrations and yet not be mobile or available for plant uptake. Phytoremediation of Se by canola (Brassica napus) was evaluated in sediment from Kesterson Reservoir at three different depths (0 to 30, 30 to 60, 60 to 90 cm) under greenhouse and field conditions. In the greenhouse study, total soil Se concentrations at preplant ranged from 10 to 112 mg kg−1. Shoot Se concentrations of canola were 182, 53, and 19 mg kg−1 DM in the 0 to 30, 30 to 60, and 60 to 90 cm depths, respectively. Percentages of Se accumulated by canola relative to total Se loss in the soil at postharvest were as high as 24%. In the field study, total soil Se concentrations were as high as 26 mg kg−1 soil. Field-grown canola accumulated approximately 50 mg kg−1 DM, which accounted for less than 10% of total Se lost in the soil at postharvest. Phytoremediation of Se-laden soils under field conditions was about 50% of that observed under controlled greenhouse conditions. Th...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"216 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115980336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334384
Andrew C. P. Heaton, C. L. Rugh, Nian-jie Wang, R. Meagher
Inorganic mercury in contaminated soils and sediments is relatively immobile, though biological and chemical processes can transform it to more toxic and bioavailable methylmercury. Methylmercury is neurotoxic to vertebrates and is biomagnified in animal tissues as it is passed from prey to predator. Traditional remediation strategies for mercury contaminated soils are expensive and site-destructive. As an alternative we propose the use of transgenic aquatic, salt marsh, and upland plants to remove available inorganic mercury and methylmercury from contaminated soils and sediments. Plants engineered with a modified bacterial mercuric reductase gene, merA, are capable of converting Hg(II) taken up by roots to the much less toxic Hg(0), which is volatilized from the plant. Plants engineered to express the bacterial organo-mercurial lyase gene, merB, are capable of converting methylmercury taken up by plant roots into sulfhydryl-bound Hg(II). Plants expressing both genes are capable of converting ionic mercu...
{"title":"Phytoremediation of Mercury- and Methylmercury-Polluted Soils Using Genetically Engineered Plants","authors":"Andrew C. P. Heaton, C. L. Rugh, Nian-jie Wang, R. Meagher","doi":"10.1080/10588339891334384","DOIUrl":"https://doi.org/10.1080/10588339891334384","url":null,"abstract":"Inorganic mercury in contaminated soils and sediments is relatively immobile, though biological and chemical processes can transform it to more toxic and bioavailable methylmercury. Methylmercury is neurotoxic to vertebrates and is biomagnified in animal tissues as it is passed from prey to predator. Traditional remediation strategies for mercury contaminated soils are expensive and site-destructive. As an alternative we propose the use of transgenic aquatic, salt marsh, and upland plants to remove available inorganic mercury and methylmercury from contaminated soils and sediments. Plants engineered with a modified bacterial mercuric reductase gene, merA, are capable of converting Hg(II) taken up by roots to the much less toxic Hg(0), which is volatilized from the plant. Plants engineered to express the bacterial organo-mercurial lyase gene, merB, are capable of converting methylmercury taken up by plant roots into sulfhydryl-bound Hg(II). Plants expressing both genes are capable of converting ionic mercu...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114636979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334410
E. Carman, Tom L. Crossman, E. Gatliff
Phytoremediation has been implemented at an industrial site in Wisconsin to promote in situ remediation of No. 2 fuel oil-contaminated soil. The goal of the project is to utilize microbial-enhancing processes within the rhizosphere of trees to stimulate biodegradation of diesel range organics (DROs) within four contaminated hot spots at the site. Between 40 and 90% reductions in the concentrations of the DROs were observed over the course of a 24-week bench-scale bioventing study performed in 1994. In addition to a reduction in the concentration of DROs, the chromatograms for those analyses exhibited a relative decrease in the proportion of the more water soluble and available shorter chained or lower molecular weight DROs compared to their higher molecular weight counterparts in the fuel. In addition to a decrease in concentration, this observed change in the pattern of the chromatograms over time is consistent with biodegradation of DROs. An agronomic assessment performed in 1995 indicated that conditio...
{"title":"Phytoremediation of No. 2 fuel oil-contaminated soil.","authors":"E. Carman, Tom L. Crossman, E. Gatliff","doi":"10.1080/10588339891334410","DOIUrl":"https://doi.org/10.1080/10588339891334410","url":null,"abstract":"Phytoremediation has been implemented at an industrial site in Wisconsin to promote in situ remediation of No. 2 fuel oil-contaminated soil. The goal of the project is to utilize microbial-enhancing processes within the rhizosphere of trees to stimulate biodegradation of diesel range organics (DROs) within four contaminated hot spots at the site. Between 40 and 90% reductions in the concentrations of the DROs were observed over the course of a 24-week bench-scale bioventing study performed in 1994. In addition to a reduction in the concentration of DROs, the chromatograms for those analyses exhibited a relative decrease in the proportion of the more water soluble and available shorter chained or lower molecular weight DROs compared to their higher molecular weight counterparts in the fuel. In addition to a decrease in concentration, this observed change in the pattern of the chromatograms over time is consistent with biodegradation of DROs. An agronomic assessment performed in 1995 indicated that conditio...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132959772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-07-01DOI: 10.1080/10588339891334375
R. Rivera, V. Medina, S. Larson, S. McCutcheon
Phytoremediation is a viable technique for treating nitroaromatic compounds, particularly munitions. Continuous flow phyto-reactor studies were conducted at the following three influent concentrations of 2,4,6-trinitrotoluene (TNT): 1, 5, and 10 ppm. A control was also prepared with an influent TNT concentration of 5 ppm. Flow rates were systematically reduced to increase hydraulic retention times (HRT) which ranged from 12 to 76 days. Initially, the control reactor removed TNT as efficiently as the plant reactors. With time, however, the efficiency of the control became less than that of the plant reactors, suggesting that adsorption was initially the mechanism for removal. Up to 100% of the TNT was removed. Aminodinitrotoluene (ADNT) effluent concentration was higher for higher TNT influent concentrations. Increasing the retention time reduced ADNT concentration in the effluent. Supplementary batch studies confirmed that ADNT and diaminonitrotoluene (DANT) were phytodegraded. Preliminary batch studies w...
{"title":"Phytotreatment of TNT-Contaminated Groundwater","authors":"R. Rivera, V. Medina, S. Larson, S. McCutcheon","doi":"10.1080/10588339891334375","DOIUrl":"https://doi.org/10.1080/10588339891334375","url":null,"abstract":"Phytoremediation is a viable technique for treating nitroaromatic compounds, particularly munitions. Continuous flow phyto-reactor studies were conducted at the following three influent concentrations of 2,4,6-trinitrotoluene (TNT): 1, 5, and 10 ppm. A control was also prepared with an influent TNT concentration of 5 ppm. Flow rates were systematically reduced to increase hydraulic retention times (HRT) which ranged from 12 to 76 days. Initially, the control reactor removed TNT as efficiently as the plant reactors. With time, however, the efficiency of the control became less than that of the plant reactors, suggesting that adsorption was initially the mechanism for removal. Up to 100% of the TNT was removed. Aminodinitrotoluene (ADNT) effluent concentration was higher for higher TNT influent concentrations. Increasing the retention time reduced ADNT concentration in the effluent. Supplementary batch studies confirmed that ADNT and diaminonitrotoluene (DANT) were phytodegraded. Preliminary batch studies w...","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133365915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-05-01DOI: 10.1080/10588339891334294
D. Steffy, C. Johnston, D. Barry
Long-column laboratory tests were performed to validate improvements to the MOFAT program for simulating LNAPL displacement and entrapment in response to a fluctuating water table. The long-column tests consisted of a fluctuating water table and its subsequent displacement and entrapment of an LNAPL. The modifications of MOFAT include a linear LNAPL trapping estimate and a new scaling technique for the inhibition portion of the fluctuation (water table rise). Improved prediction of the LNAPL trapping was obtained by assuming the amount of LNAPL that is trapped by a rising water table is proportional to the antecedent water content of the porous medium. The pressure- saturation relationship for the air- water drainage system was scaled to estimate the LNAPL- water and air-LNAPL drainage relationships. Scaled inhibition pressure- saturation relationships are improved by incorporating a correction for contact angle hysteresis and surface roughness. The incorporation of these changes into MOFAT led to noticable improvements in the numerical simulation of the experimental data.
{"title":"Numerical Simulations and Long-Column Tests of LNAPL Displacement and Trapping by a Fluctuating Water Table","authors":"D. Steffy, C. Johnston, D. Barry","doi":"10.1080/10588339891334294","DOIUrl":"https://doi.org/10.1080/10588339891334294","url":null,"abstract":"Long-column laboratory tests were performed to validate improvements to the MOFAT program for simulating LNAPL displacement and entrapment in response to a fluctuating water table. The long-column tests consisted of a fluctuating water table and its subsequent displacement and entrapment of an LNAPL. The modifications of MOFAT include a linear LNAPL trapping estimate and a new scaling technique for the inhibition portion of the fluctuation (water table rise). Improved prediction of the LNAPL trapping was obtained by assuming the amount of LNAPL that is trapped by a rising water table is proportional to the antecedent water content of the porous medium. The pressure- saturation relationship for the air- water drainage system was scaled to estimate the LNAPL- water and air-LNAPL drainage relationships. Scaled inhibition pressure- saturation relationships are improved by incorporating a correction for contact angle hysteresis and surface roughness. The incorporation of these changes into MOFAT led to noticable improvements in the numerical simulation of the experimental data.","PeriodicalId":433778,"journal":{"name":"Journal of Soil Contamination","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116446294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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