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Removal of Trichloroethylene from Contaminated Soil Using Quicklime Application

Permanent Link: http://ufdc.ufl.edu/UFE0021130/00001

Material Information

Title: Removal of Trichloroethylene from Contaminated Soil Using Quicklime Application
Physical Description: 1 online resource (92 p.)
Language: english
Creator: Jordan, Aaron A
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2007

Subjects

Subjects / Keywords: contaminant, envrionment, hazardous, quicklime, remediation, trichloroethylene, waste
Environmental Engineering Sciences -- Dissertations, Academic -- UF
Genre: Environmental Engineering Sciences thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: My study was motivated by efforts to remediate a site in Fairbanks, Florida contaminated with dense non-aqueous phase liquids (DNAPLs). Quicklime was applied on site to soils high in clay content to improve the workability of the material. Tests results soils indicated that after quicklime application, concentrations of the contaminants were reduced below the threshold for leachable soil cleanup target levels. As result of those findings, tests were conducted to evaluate quicklime as a potential soil remediation method on various soil types. One objective of the research was to determine the extent to which soil texture affects the efficiency of the quicklime remediation process. Additional objectives included determining whether abiotic decomposition of TCE occurs. Four soil textures were selected: sand, sand from an organic horizon, sandy clay loam, and sandy clay. The analysis consisted of filling a drum with 50 kg of soil (10% water content); artificially contaminating the soil with TCE (34.68 ml concentrate); rotating the mixture; taking an initial soil sample; and then treating with 0%, 2%, 5%, and 10% doses of quicklime by weight. The TCE concentration and chloride concentration were evaluated before and after quicklime application to evaluate the effects of quicklime in all four soil types. The results from the first objective indicate that a quicklime dose greater than 5% after 3 hours removes at least 86% of TCE with an initial average concentration of 150-390 mg/kg wet soil. The sand E soil and sandy clay loam consistently displayed the greatest removal of TCE and the soils with higher clay content ( > 31%) lost the least. The results of this study indicate that the addition of quicklime does not consistently reduce the concentration of TCE below leachability groundwater target cleanup levels within 24 hours of treatment with one application of quicklime (0.03 mg/kg GWTCL). However, a quicklime application of greater than 5% can reduce concentrations of TCE below residential direct exposure soil cleanup target levels (6.4 mg/kg). The result from the second objective was mixed and complex. Chloride ion was used an indirect indicator to determine if TCE was decomposing as result of quicklime addition. In two soil types, sand and sand with higher organic matter, the chloride concentration did not increase or decrease as a result quicklime application. In the two soils tested with larger percent of fines, the level of extractable chloride decreased with quicklime application. The data from the decomposition analyses suggested that volatilization was the main mechanism for removal in all soil types because the lack of increase chloride concentration after quicklime addition. Because there is potential through decomposition of TCE to produce more toxic forms of chlorinated compounds, these concerns has not been confirmed by these results. However, the analysis is only an indirect measurement and would require further analysis to determine if decomposition is a potential. Thus, the potential for quicklime to be used as form of remediation is plausible and effective. The data shows that quicklime can sufficiently reduce TCE in several soil types.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Aaron A Jordan.
Thesis: Thesis (M.S.)--University of Florida, 2007.
Local: Adviser: Townsend, Timothy G.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2008-08-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2007
System ID: UFE0021130:00001

Permanent Link: http://ufdc.ufl.edu/UFE0021130/00001

Material Information

Title: Removal of Trichloroethylene from Contaminated Soil Using Quicklime Application
Physical Description: 1 online resource (92 p.)
Language: english
Creator: Jordan, Aaron A
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2007

Subjects

Subjects / Keywords: contaminant, envrionment, hazardous, quicklime, remediation, trichloroethylene, waste
Environmental Engineering Sciences -- Dissertations, Academic -- UF
Genre: Environmental Engineering Sciences thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: My study was motivated by efforts to remediate a site in Fairbanks, Florida contaminated with dense non-aqueous phase liquids (DNAPLs). Quicklime was applied on site to soils high in clay content to improve the workability of the material. Tests results soils indicated that after quicklime application, concentrations of the contaminants were reduced below the threshold for leachable soil cleanup target levels. As result of those findings, tests were conducted to evaluate quicklime as a potential soil remediation method on various soil types. One objective of the research was to determine the extent to which soil texture affects the efficiency of the quicklime remediation process. Additional objectives included determining whether abiotic decomposition of TCE occurs. Four soil textures were selected: sand, sand from an organic horizon, sandy clay loam, and sandy clay. The analysis consisted of filling a drum with 50 kg of soil (10% water content); artificially contaminating the soil with TCE (34.68 ml concentrate); rotating the mixture; taking an initial soil sample; and then treating with 0%, 2%, 5%, and 10% doses of quicklime by weight. The TCE concentration and chloride concentration were evaluated before and after quicklime application to evaluate the effects of quicklime in all four soil types. The results from the first objective indicate that a quicklime dose greater than 5% after 3 hours removes at least 86% of TCE with an initial average concentration of 150-390 mg/kg wet soil. The sand E soil and sandy clay loam consistently displayed the greatest removal of TCE and the soils with higher clay content ( > 31%) lost the least. The results of this study indicate that the addition of quicklime does not consistently reduce the concentration of TCE below leachability groundwater target cleanup levels within 24 hours of treatment with one application of quicklime (0.03 mg/kg GWTCL). However, a quicklime application of greater than 5% can reduce concentrations of TCE below residential direct exposure soil cleanup target levels (6.4 mg/kg). The result from the second objective was mixed and complex. Chloride ion was used an indirect indicator to determine if TCE was decomposing as result of quicklime addition. In two soil types, sand and sand with higher organic matter, the chloride concentration did not increase or decrease as a result quicklime application. In the two soils tested with larger percent of fines, the level of extractable chloride decreased with quicklime application. The data from the decomposition analyses suggested that volatilization was the main mechanism for removal in all soil types because the lack of increase chloride concentration after quicklime addition. Because there is potential through decomposition of TCE to produce more toxic forms of chlorinated compounds, these concerns has not been confirmed by these results. However, the analysis is only an indirect measurement and would require further analysis to determine if decomposition is a potential. Thus, the potential for quicklime to be used as form of remediation is plausible and effective. The data shows that quicklime can sufficiently reduce TCE in several soil types.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Aaron A Jordan.
Thesis: Thesis (M.S.)--University of Florida, 2007.
Local: Adviser: Townsend, Timothy G.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2008-08-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2007
System ID: UFE0021130:00001


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1 REMOVAL OF TRICHLOROETHLYENE FR OM CONTAMINATED SOIL USING QUICKLIME APPLICATION by AARON A. JORDAN A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2007

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2 2007 Aaron Jordan

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3 To my Parents

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4 ACKNOWLEDGMENTS I thank my committee chair, Dr. Timothy To wnsend, for constant guidance, inspiration, and encouragement during my years as laboratory assistant and throughout my graduate studies. I also thank my fellow graduate students, especi ally Dr. Jeahac Ko for his mentoring, constant source of knowledge, and friendship. In addition, I thank Steve Musson for his assistance in organizing my research. I would also like to thank two very important men, Dr. Hwidong Kim and Dr. Brajesh Dubey, for their help and advice with various anal ytical instruments used in this study and in previous work under Dr. Townsend. Without the support of all my undergraduate and graduate professors I would not have to essential skills to complete my research, in particular Dr. Willie Harris. I thank my Mother and Father. Throughout my life they have been a source of direction and love. Most importantly my personal relations hip with God has been the driving force behind my success.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS...............................................................................................................4 LIST OF TABLES................................................................................................................. ..........7 LIST OF FIGURES................................................................................................................ .........8 ABSTRACT....................................................................................................................... ............11 CHAPTER 1 INTRODUCTION..................................................................................................................13 1.1 Background and Problem Statement...............................................................................13 1.2 Research Objectives....................................................................................................... ..15 1.3 Research Approach......................................................................................................... .15 2 LITERATURE REVIEW.......................................................................................................17 2.1 Problems Associated with Soils Cont aminated with Chlorinated Solvents....................17 2.2 Typical Remediation Approaches....................................................................................18 2.3 Remediation Goals......................................................................................................... ..19 2.4 The Fairbanks Site........................................................................................................ ...20 2.5 Previous Quicklime Studies.............................................................................................21 2.6 Ko Evaluation of Quicklime Mechanisms of VOC Removal.........................................22 3 MATERIALS AND METHODS...........................................................................................29 3.1 Method Overview........................................................................................................... .29 3.2 Soil Selection and Information........................................................................................29 3.3 Experimental Apparatus Vessel-Drum............................................................................30 3.4 Test Preparation and Initial Soil Sample.........................................................................31 3.5 Quicklime Addition and 3and 24-Hour Sampling Event..............................................33 3.6 Analysis Instrumentation.................................................................................................34 3.7 Statistical Analysis Software ANOVA............................................................................34 4 RESULTS AND DISCUSSION.............................................................................................40 4.1 Temperature Profiles with Quicklime addition and Soil Texture....................................40 4.1.1 Temperature Profiles in soils with 2% Quicklime Addition.................................40 4.1.2 Temperature Profiles in soils with 5% Quicklime Addition.................................40 4.1.3 Temperature Profiles in soils with 10% Quicklime Addition...............................41 4.2 Impacts of Soil Textures on TCE Removal with Quicklime Addition............................42 4.2.1 TCE Concentration with No Quicklime Application............................................42 4.2.2 TCE Removal with 2% Quicklime Application....................................................43

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6 4.2.3 TCE Removal with 5% Quicklime Application....................................................43 4.2.4 TCE Removal with 10% Quicklime Application..................................................44 4.3 TCE Removal with Depth of th e Quicklime-Treated Materials......................................46 4.4 Chloride Analysis with Respect to Soil Depth................................................................47 4.5 Soil pH Analysis.......................................................................................................... ....48 5 CONCLUSIONS....................................................................................................................65 5.1 Summary and Conclusions..............................................................................................65 5.2 Limitations, Implications, and Recommendations..........................................................67 APPENDIX A COMPLETE LIST OF ALL DOCUME NTED TCE REMOVAL ANALYSIS....................69 B CHLORIDE CONCENTRATION.........................................................................................77 C EXCEL WORSHEET TO PR EDICT TCE ADDITION........................................................85 D STATISTICAL SUMMARY.................................................................................................88 LIST OF REFERENCES............................................................................................................. ..91 BIOGRAPHICAL SKETCH.........................................................................................................92

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7 LIST OF TABLES Table page 2-1 List of Hazardous Volatile Organi c Compounds (US Environmental Protection AgencySW-846)..............................................................................................................25 2-2 Examples of Remedial Action Treatment Technologies...................................................25 2-3 Soil Cleanup Target Levels and Maximum Contaminant Level for TCE.........................26 3-1 Particle Text ure Distribution..............................................................................................35 3-2 Organic Carbon Data........................................................................................................ .35 3-3 Sampling Inventory for Initial Soil Samples.....................................................................37 3-4 Summary of Sample Met hod Inventory after 3 Hours.......................................................37 4-1 TCE removal in four soil types wi th respect to quicklime applications............................56 4-2 pH Summary of adding quicklime to f our soil types: Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay.......................................................................................................64 C-1 Excel worksheet used to calculate TCE volumes..............................................................86 D-1 Summary of TCE concentration mg/ kg in Sand E, Sandy Clay Loam, and Sandy Clay with No Quicklime Added after 24 Hours................................................................88 D-2 Summary of TCE Concentration Between all Soil Tested after 24 Hours with No Quicklime Application.......................................................................................................88 D-3 Statistic Summary for 5% TCE Removal after 24 Hours..................................................89 D-4 Statistical Summary between Sandy Clay TCE concentrations and the other Three Soil types tested after 10% Applicat ion of Quicklime after 24 Hours..............................90 D-5 Summary of TCE Concentration Between all Soil Tested afte r 24 Hours with 10% Quicklime Application.......................................................................................................90

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8 LIST OF FIGURES Figure page 2-1 Basic lithology of Fairbanks..............................................................................................26 2-2 Map of Fairbanks and contaminated site (FDOT, 2002)...................................................27 2-3 Map of contamination plume at Fairbanks (FDOT, 2002)................................................28 3-1 Sampling schedule of soils tested......................................................................................36 3-2 Schematic of Drum Test Vessel (not drawn to scale)........................................................38 3-3 Sampling Tube and Layer Delineation..............................................................................39 4-1 Two-percent quicklime addition and soil temperature recordings in Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay............................................................................49 4-2 Five-percent quicklime addition and soil te mperature recordings in Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay...................................................................................50 4-3 Ten-percent quicklime addition and soil te mperature recordings in Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay...................................................................................51 4-4 TCE concentration at 0 Hours (A) and TCE concentration after 24 Hours (B) No quicklime added to Sand E, Sand AE, Sandy Clay Loam, or Sandy Clay........................52 4-5 TCE concentration at 0 Hours (A) and TCE concentration after 24 Hours (B) 2% quicklime added to Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay......................53 4-6 TCE concentration at 0 Hours (A) a nd TCE concentration after 24 hours (B) 5% quicklime added to Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay......................54 4-7 TCE concentration at 0 Hours (A) and TCE concentration after 24 (B) 10% quicklime added to Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay......................55 4-8 Summary of TCE removal in all soil types with respect to time.......................................57 4-9 TCE concentration after 3 hours with respect to soil depth after quicklime addition. The dotted line is the initial concentration before quicklime is added (0 Hour). The error bars indicate standard deviation. (A) Sand E; (B ) Sand AE; (C) Sandy Clay Loam; (D) Sandy Clay.......................................................................................................58 4-10 Sand E. Decomposition of TCE chlorid e ions with respect to soil depth and quicklime addition.............................................................................................................60 4-11 Sand AE. Decomposition of TCE chlorid e ions with respect to soil depth and quicklime addition.............................................................................................................61

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9 4-12 Sandy Clay Loam. Decomposition of TCE c hloride ions with respect to soil depth and quicklime addition.......................................................................................................62 4-13 Sandy Clay. Decomposition of TCE chlor ide ions with respect to soil depth and quicklime addition.............................................................................................................63 A-1 Sand E 0% CaO Treatment................................................................................................69 A-2 Sand E 2% CaO Treatment................................................................................................69 A-3 Sand E 5% CaO Treatment................................................................................................70 A-4 Sand E 10% CaO Treatment..............................................................................................70 A-5 Sandy Clay Loam 0% CaO Treatment...............................................................................71 A-6 Sandy Clay Loam 2% CaO Treatment...............................................................................71 A-7 Sandy Clay Loam 5% CaO Treatment...............................................................................72 A-8 Sandy Clay Loam 10% CaO Treatment.............................................................................72 A-9 Sandy Clay 0% CaO Treatment.........................................................................................73 A-10 Sandy Clay 2% CaO Treatment.........................................................................................73 A-11 Sandy Clay 5% CaO Treatment.........................................................................................74 A-12 Sandy Clay 10% CaO Treatment.......................................................................................74 A-13 Sand A/E 0% CaO Treatment............................................................................................75 A-14 Sand A/E 2% CaO Treatment............................................................................................75 A-15 Sand A/E 5% CaO Treatment............................................................................................76 A-16 Sand A/E 10% CaO Treatment..........................................................................................76 B-1 Sand E-Horizon with No Quicklime..................................................................................77 B-2 Sand E-Horizon with 2% Quicklime.................................................................................77 B-3 Sand E-Horizon with 5% Quicklime.................................................................................78 B-4 Sand E-Horizon with 10% Quicklime...............................................................................78 B-5 Sandy Clay Loam with No Quicklime...............................................................................79 B-6 Sandy Clay Loam with 2% Quicklime..............................................................................79

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10 B-7 Sandy Clay Loam with 5% Quicklime..............................................................................80 B-8 Sandy Clay Loam with 10% Quicklime............................................................................80 B-9 Sandy Clay with No Quicklime.........................................................................................81 B-10 Sandy Clay with 2% Quicklime.........................................................................................81 B-11 Sandy Clay with 5% Quicklime.........................................................................................82 B-12 Sandy Clay with 10% Quicklime.......................................................................................82 B-13 Sand AE-Horizon with No Quicklime...............................................................................83 B-14 Sand AE-Horizon with 2% Quicklime..............................................................................83 B-15 Sand AE-Horizon with 5% Quicklime..............................................................................84 B-16 Sand AE-Horizon with 10% Quicklime............................................................................84

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11 Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science REMOVAL OF TRICHLORETHYLENE FR OM COMTAMINATED SOIL USING QUICKLIME APPLICATION By Aaron A. Jordan August 2007 Chair: Timothy Townsend Major: Environmental Engineering Sciences My study was motivated by efforts to remediate a site in Fairbanks, Florida contaminated with dense non-aqueous phase liqui ds (DNAPLs). Quicklime was a pplied on site to soils high in clay content to improve the workability of the ma terial. Tests results so ils indicated that after quicklime application, concentrations of the cont aminants were reduced below the threshold for leachable soil cleanup target levels. As result of those findings, tests were conducted to evaluate quicklime as a potential soil remedi ation method on various soil types. One objective of the research was to determine the extent to which soil texture affects the efficiency of the quicklime remediation proces s. Additional objectives included determining whether abiotic decomposition of TCE occurs. Four soil textures were selected: sand, sand from an organic horizon, sandy clay loam, and sandy clay. The analysis consisted of filling a drum with 50 kg of soil (10% water content); artificially contaminating the soil with TCE ( 34.68 ml concentrate); rota ting the mixture; taking an initial soil sample; and then treating w ith 0%, 2%, 5%, and 10% doses of quicklime by weight. The TCE concentration and chloride co ncentration were evaluated before and after quicklime application to eval uate the effects of quicklime in all four soil types.

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12 The results from the first objective indicate that a quicklime dose greater than 5% after 3 hours removes at least 86% of TCE with an in itial average concentration of 150-390 mg/kg wet soil. The sand E soil and sandy clay loam consis tently displayed the gr eatest removal of TCE and the soils with higher clay content (> 31%) lost the least. The results of this study indicate that the addition of quicklime does not consistently reduce the concentration of TCE below leachability groundwater target cleanup levels with in 24 hours of treatment with one application of quicklime (0.03 mg/kg GWTCL). However, a qui cklime application of greater than 5% can reduce concentrations of TCE below residential direct exposure soil cleanup target levels (6.4 mg/kg). The result from the second objective was mixed and complex. Chloride ion was used an indirect indicator to determine if TCE was decomposing as result of quicklime addition. In two soil types, sand and sand with higher organic matte r, the chloride concentr ation did not increase or decrease as a result quicklime ap plication. In the two soils tested with larger percent of fines, the level of extractable chloride decreased w ith quicklime application. The data from the decomposition analyses suggested that volatilizat ion was the main mechanism for removal in all soil types because the lack of increase chlo ride concentration af ter quicklime addition. Because there is potential through decomposition of TCE to produce more toxic forms of chlorinated compounds, these concerns has not b een confirmed by these results. However, the analysis is only an indirect measurement and would require further anal ysis to determine if decomposition is a potential. Thus, the potential for quicklime to be used as form of remediation is plausible and effective. Th e data shows that quicklime can sufficiently reduce TCE in several soil types.

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13 CHAPTER 1 INTRODUCTION 1.1 Background and Problem Statement Dense Non-Aqueous Phase Liquid (DNAPL) has the ability to disperse throughout soils into geological parent material s, often creating pools on top of semi-impermeable subsurface formations or at the bottom of aquifers, crea ting long-term sources of contaminant plumes. These plumes often travel in the direction of groundwater flow, thus potentially entering drinking-water supplies a nd threatening human health. This is the scenario that occurred at a Florida Department of Transportation disposal-tes ting facility in Fairbank s, Florida. Fairbanks Disposal Pit (FDP) is located north of Gain esville, Florida on Highway 24. The site was purchased by the Florida Department of Trans portation (FDOT) to test the quality of asphalt paving materials and to use as a disposal si te (borrow pit) for t opsoil and constructiondemolition debris. To test the quality of the asphalt, the facility used a variety of chlorinated solvents. The method of disposing of the mate rials and residues from laboratory was not consistent. Because the solvents were someti mes dumped directly into the ground and a number of drums were found leaking, the site was c ontaminated. The major contaminants found at Fairbanks included trichloroethyl ene, 1-1-1 trichloroethane, 11-dichloroethylene, and benzene (FDOT, 2002). In 1995, as a part of the remediation actions FDOT removed drums of contaminants and installed a groundwater treatment system. Since the concentrations of contaminants did not sufficiently decrease in the groundw ater following in-situ treatment, FDOT excavated the area to remove the source of contamination. The init ial remediation plan was to use soil vacuum extraction to treat the excavated soils. Before treatment, the soils were processed to remove rocks and nodules by using a power trommel scr een. During the excavation, the clay content

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14 increased with depth and they could not use the tr ommel screen effectively. To improve material handling, quicklime was added to amend the soil. Quicklime was mixed into the soils at appr oximately 5% of the contaminated soil to improve the soil handling characte ristics. Because quicklime is known to react with organic compounds, preliminary tests were conducted to i nvestigate if any new compounds (potentially harmful) were produced. An unexpected obser vation was made. The contaminants were removed from the soil. The results suggested that the contaminants may have been decomposed by either CaO or Ca(OH)2 interaction, encapsulated in the soil-Ca(OH)2 matrix, or volatilized from the heat of the quicklime slaking reaction. Those soils had been tested to meet the soil target levels before they we re reused on-site. Approximate ly 10,000 cubic yards of soil were treated with quicklime, saving se veral million dollars compared to off-site disposal methods (Dean, 2005). Soil properties may influence how efficientl y quicklime treatment can remove TCE and possibly other chlorinated ethylenes from soils. Soil properties and environmental conditions can influence the distribution of contaminants in soil, which may also affect the efficiency of treatment. Environmental conditions that may affect the distribution of a chemical include temperature, humidity, and wind speed (Guenzi and Beard, 1974). Also, the introduction of air when mixing quicklime has been shown to incr ease the decomposition of chlorinated ethylene with quicklime addition (Ko, 2007). Elevated temperatures can influence vapor pressure, causing the contaminant to move from greater to lesser concentration. An increase in wind speed on the soil and elevated temperatures can cause the soil to lose soil moisture, which may increase volatilization. These factors can be increase or decreased to maximize the removal of contaminants. Because of these factors, a large-scale test was developed to incorporate these

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15 conditions to determine how and to what extent quicklime will remove contaminant in different soil types. 1.2 Research Objectives The aim of my study was to assess the feas ibility of quicklime mixing as a viable technique to remediate soils contaminated with m oderate levels of TCE and determine which soil types are most amenable to treatment. Additi onally, from previous re search indicates that decomposition of TCE or possibly other chlorinate d solvents may cause the formation of other toxic organic compounds (Ko, 2007). Thus a decomposition analysis was conducted with respect to soil depth and soil type. The large-scale laboratory studies will provide recommendations for parameters such as calcium oxide amounts to be used, soil texture class most treatable, and contaminant level treatment achievable within a given period of treatment. The objectives for large-scale testing were as follows: To determine if soil texture can impact the efficiency of quicklime technology. To determine if quicklime application can effectively remove TCE throughout the soil in the test vessel. To determine if decomposition occurs after quicklime addition and, if so, are there any trends as to where the area of greatest decomposition occurs. 1.3 Research Approach As a result of those findings during excavati on, FDOT funded research to answer questions concerning the dominant mechanisms of pollutant removal and to apply th e technology close to field conditions. The research was divided into two main sectionslabor atory testing and largescale quicklime application. The laboratory te sting was performed by Dr. Jaehac Ko at the University of Florida Environmental Engineer ing Sciences Laboratory. It was designed to determine the dominant mechanisms involved in th e removal of volatile contaminants from soil using the quicklime slaking process. However, the conditions created in the laboratory may not

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16 be reproducible in the field; also conditions encountered in the fi eld may differ significantly from laboratory test conditions. To test field soil samples at soil depths similar to the conditions at Fairbanks, an intermediate large-scale test vessel was designe d. The vessel was capable of collecting larger samples from the field and therefore provided samp les representative of contaminant levels, and moisture regimes found in field applications. Th e analysis used synthesized contaminated soils to evaluate the effectiveness of the quicklim e technology and allowed comparison of the large vessel to laboratory tests to determine any differe nces before testing soils from the field. All tests were performed with the same amount or degree of TCE, method of mixing the materials, water content, sampling schedule, and quicklime. Independent variables included soil type and degree of mixing (due to plastici ty of the soil). Each soil t ype was tested four times with different CaO doses: 0% 2%, 5%, and 10% by weight. To examine if decomposition occurs as a resu lt of quicklime addition, chloride ion per unit of soil was extracted from soil samples before quicklime and after quick lime addition. Each sample was analyzed with an ion chromatogra ph (IC). Each sample was labeled depending on the soil depth it was collected fr om. Three 5-inch sections we re delineated. In addition, soil samples were simultaneously collected and, after filtering, analyzed with a gas chromatographer to determine the TCE concentrations at the sa mpling schedule to determine the ability of quicklime to remove contaminant. The soil samp les were collected in se mi-open tubes and then removed and placed into vials (please see Figure 3-3 in method section). Before being removed from the sampling tubes, the soil samples were marked and organized depending on the depth of sampling. Each section was sampled three times at a minimum for extractable chloride ions and TCE concentrations.

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17 CHAPTER 2 LITERATURE REVIEW 2.1 Problems Associated with Soils Cont aminated with Chlorinated Solvents Chlorinated ethylenes (CE) ar e a group of compounds commonl y used as solvents (Table 2-1). This study targets TCE as the contaminant to remediate since it is a primary concern at the Fairbanks site due to high concentrations found onsite. Fortunately, TCE is less toxic than some of the other chlorinated compounds present at th e site and from a health risk standpoint was a good choice to use for laboratory experiments. CE represents a large portion of volatile chemicals that re quire cleanup sinc e they pose a negative impact to human health and the environment. CE com pounds are denser than water and have low aqueous solubility, which is why they are considered dense non-aqueous phase liquids (DNAPL). If these substances are spilled into the subsurface, they have the potential of penetrating the water table and providing a l ong-term source of contamination. Chlorinated solvents within karsts geol ogy are a major concern because DNAPLs can move through tiny fissures and porous limerock (Feenstra, 1992). The chlorinated solvent contaminant mass that enters a groundwater zone can remain as a pers istent source of residual DNAPL in porous and fractured geologic media for years and even decade s after the initial release. This is possible because gases from the contaminant (TCE and ot her chlorinated solvents) can dissolve into the water, increasing the capacity and potential volume the c ontaminant can occupy (McCoy and Rolston, 1992). Thus the contaminant can persist longer period of time. Chlorinated solvents have a variety of pot ential pathways for contaminating the soil, geologic material, and groundwater. Chlorinated solvents can ente r the environment as a result of accidents, spills during transportation, industr y activity, leakage from waste disposal, or storage sites. TCE can also enter groundwater and surface water from industrial discharges or

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18 from improper disposal of industrial wastes at landfills (Cabbar and Bostance, 2001). Most often these solvents are used as a metal degreaser a nd as intermediates for other compound fabrication. Most airborne TCE comes from me tal degreasing activities associated with tool and automobile production. TCE has been found in many drinking water supplies in the United States. In homes, TCE may be found in typewriter correcti on fluid, paint, spot removers, carpet-cleaning fluids, metal cleaners, and varnishes. Once th ese organic compounds ente r the subsurface they are subjected to a series of chemical-physical transformations. In the unsaturated zone, the chemical will infiltrate downward until it reaches an area of low permeability, such as clay lens. The pure-phase product will build a residual pool underground and continue as a source of contamination. However, vapors from the residual will be absorbed into the soil moisture and travel through stormwater to ha ve a potential widespread impact The extent of contamination will depend on natural attenuation, the degree of biodegradation, and natural forces such as rainwater. (Nobre and Nobre, 2004). 2.2 Typical Remediation Approaches The government, industry, and the public are awar e of the negative eff ects associated with chlorinated solvents. In response to increased awareness, many remediation technologies have been developed. The contaminant can exist in leachate, wastewater, a nd groundwater and there are in-situ and ex-situ methods of remediating th e contaminant. The selection of appropriate remediation technology is site specific, base d on properties of the contaminant and the environment (soil texture, temperature, depth to water table, hydrauli c conductivity, etc) (Khan, et al. 2004). After site evaluation and assessment of reme diation strategy, it is very common that a particular site may require a combination of remediation technologies. Two classes of remediation approaches can be employed to treat soils: in situ, where the soil is treated in the

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19 ground, and ex-situ, when the soil and contaminan t are removed and then treated above ground. Recently, several in-situ methods have been developed over excavation (ex-situ), since excavation tends to be more expensive. Despite the cost, the ability to completely remove the contaminant by excavation is a more-effectiv e option. Although ex cavation removes the contaminant it is often combined with additional treatments (Khan et al., 2004). A list of typical methods of remediation is provided in (Table 2-2). Two other methods of remediation are containm ent and transformation. Containment uses physical barriers, sorption walls, and hydraulics. Transformation is divided into two main groups, thermal-chemical and bioremediation. U nder thermal-chemical transformation there are at least four plausible options; 1) vitrification, 2) inci neration, 3)volatilization, and 4) chemical oxidation. Bioremediation strategies can ta ke various levels of action or no action. 2.3 Remediation Goals Depending on the objectives, a site manager can apply several standards for remediation. Soil Cleanup Target Levels (SCTL) assess the e fficacy of the remediation technology. Several states implement their own target levels for toxic waste. On a national level, Federal Drinking Water standards establish primary and seconda ry maximum contaminant levels (MCL) and maximum contaminant level goals (MCLG). Add itionally, risk-based concentration levels are also considered, depending upon the need for re mediation. Table 2-3 presents SCTL and MCL for TCE. Depending on the use and environment, th e appropriate target leve ls will be enforced. Because the contaminants were polluting the grou ndwater at the Fairbanks site, the leachable groundwater cleanup target levels were applied. The GWTCL for TCE must meet the primary standard (MCL), which is 0.005 mg/L. After pa ssing the GWTCL, the Fairbanks soil was reused after excavation on-site. However if the soil were to be reused in a residential application the standard SCTL would also apply.

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20 2.4 The Fairbanks Site The Fairbanks Disposal Pit (FDP) is approxima tely 7 miles north of Gainesville, Florida on Highway 24, specifically at 8000 NE 51st Street in the small to wn (population 750) of Fairbanks in Alachua County. It is approximately 3 miles nort heast of Gainesville Regional Utilities Murphee Wellfield (See Figure 2-2). The site consists of 75 acres, including a 10-acre landfill-former borrow pit. Fairbanks main source of drinking water is local artesian wells. The local groundwater was exposed to several contam inants. A site map of the basic lithology, a general site map, and a detail map of contaminat ion zone are included as Figures 2-1, 2-2, and 23. Over a 40-year time span the Fairbanks site ha s been used in numerous ways. Originally it was a sand and borrow pit used to supply materi al for road construction. In 1956, the site accepted topsoil generated from road construction, demolition debris, and material collected from roadsides. FDOT purchased the site to te st the quality of asphalt used in paving material and disposed onsite the waste generated at th e FDOT Bureau of Mate rials Research (BMR) Laboratory. These disposal activities continued until 1982 (FDOT, 2002). Throughout the history at the BM R, activities performed require d the use of a variety of chlorinated solvents to test the quality of asphalt materials. The residues from the testing include several toxic compounds. The toxic compounds th emselves originate from the chlorinated solvents and the partially decomposed asphalt material. From 1956 to 1961, carbon tetrachloride was used as a solvent to disso lve samples. Later, carbon tetr achloride was replaced with 1,1,1trichloroethane and in the early 1970s the ma nagement switched to trichloroethylene. The DNAPL was located on top of an impervious clay lens and diffused into the first layer (Hawthorne layer) at approximately 35 to 45 f eet below land surface (bls) as shown in Figure 21. The 10-acre site was subject to the Resour ce Conservation and Recovery Act (RCRA) with

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21 amended provisions set by the 1984 Hazardous and Solid Waste Amendments. During excavation from 1983 to 1995, 1426 drums were remove d from the site. These drums contained residues from the testing of asphalt. The residues stemmed from the asphalt itself and the remains of the solvents used in the testing (FDOT, 2002). The procedure was to divide all excavated soil into piles classified as clean and dirty. FDOT designated dirty as any contaminant greater than one part per billi on (ppb) regardless of contamination type. In all, FDOT reported that 111,688 cubic yards of soil were excavated, power screened to remove debris, and placed in to 100-cubic-yard bins and sampled. It was reported that 1214 bins were sampled. The FDOT used industrial standards to determine the threshold value. A total of 111,132 cubic yards of soil were treated and transported for disposal in Chambers Landfill (FDOT, 2002). In Figure 2-3 the extent of the contamination plume is documented. The contamination plume moves north toward Hatchet Creek (not shown in map). The site method for locating contamina tions consisted of excavating until zero contamination was present in soil and then probing ahead of the excavation for more contaminant. When no contaminant was found, ex cavation ended. In general, the excavation ended at the beginning of the firs t Hawthorne layer at approximate ly 35 feet bls. The soil was very difficult to work due to an increase in clay content. Onsite managers decided to amend the soil with quicklime to increase the workability of the soil. Thus, they created the piles to be treated. Quicklime application led to th e removal of several VOCs including TCE. 2.5 Previous Quicklime Studies Previous studies have reported that the appare nt diffusivitiy of VOCs in soils depends on soil properties, temperature, and soil moisture. Sorption type (linear equilibrium, non-linear BET isotherm, etc) can also affect the apparent diffusivity of VOCs in soils. Soil adsorption factors can affect contaminant movement and retention. Other studie s suggested that in

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22 unsaturated soils the sorption of vapor phase contaminants in wate r contributes to retardation of diffuse transport (McCoy and Rolston, 1992; Te krony and Ahlert, 2001). For oven-dried soils, adsorption correlates directly to total surf ace area (Rhue and Rao, 1990). Additionally, the importance of adsorbent properties, such as organic matter content a nd excess surface energy, increases with soil water content as less polar organic molecules compete for available sorption sites (Peterson, et al. 1988). In porous media such as sandy soil, adsorption is limited by pore size distribution and as absorbent molecules accumulate in multiple layers total adsorption is constrained by the emissions of in traand inter-particle pores. 2.6 Ko Evaluation of Quicklim e Mechanisms of VOC Removal Ko (2007) has been working at the Universi ty of Florida Environmental Engineering Science Laboratories to answer questions regarding the reacti ons involved with hydration of quicklime and chlorinated compounds removed from a soil matrix as a result of the reaction. His dissertation evaluates the mechanisms for contaminant removal from soil as a result of slaking with quicklime. His assessment was confined to several labora tory exercises performed under small-scale conditions. Under these conditions he developed a testing reactor to isolate mechanisms involved in the quicklime reactions to soil contaminated with several chlorinated hydrocarbons. He tested the e ffects of excess water, the pres ence of air, and mechanisms responsible for destruction or removal of TCE a nd other chlorinated ethylenes in four separate studies. In the first study Kos primary objective was to determine the destru ction of chlorinated ethylenes when quicklime reacts with a chlorina ted ethylene-water mixture (note without soil matrix). Within this study he measured organic byproducts and chlo ride in chlorinated ethylenes, determined the impacts of water on th e formation of byproducts with different ratios

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23 of quicklime-H2O, and compared the byproduct with presence and absence of air. The results of this study are as follows: Abiotic destruction of chlorinated ethylenes doe s occur when quicklime reacts with chlorinatedH2O. Ca(OH)2 may have had a major role for th e abiotic destruction to occur. Excess water hindered the formation of byproducts in the quicklime chlorinated-H2O reaction. The abiotic reaction destruction in the presence of air lead to formation of many diverse organic byproducts. Based on the first object the second study prim ary objective was to ve rify the role of Ca(OH)2 on the reaction when TCE is directly exposed to Ca(OH)2 under different temperatures. In addition, the formation byproducts were meas ured over time. The results are as follows: Ca(OH)2 decomposed TCE on direct contact. The formation of dichloroacteylene (DCA) and chloride from the reaction of Ca(OH)2 with TCE increased with increase in temperature. Both DCA and chloride increased in the beginning of the reaction and then remained stable over time. In the third study the experiments were designed to explore the destru ction of chlorinated ethylenes in three soil types by CaO application with different CaO-H2O ratios. In these experiments the temperature was measured as a result quicklime addition. In addition, the extractable chloride was measured by treating the contaminated soil types with different CaO/H2O ratios. The results of this study are as follows: Temperature rise in coarse sand samples were faster and higher than those in loamy sand with same quicklime to water ratios. As the quicklime-to-water ratios increase d the extractable chloride concentration increased. The extractable chloride levels in loam y sand were lower than in coarse sand.

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24 In the fourth study volatilization and destruc tion of TCE from soils by CaO addition were explored. In a similar manner as in Study 3, in th is set of experiments the volatilizat ion of TCE was measured with different quicklime to water ra tios. The byproducts were also measured in the soil samples. The important findings from this experiment are as follows: Quicklime treatment in two sandy soils after 3 hours resulte d in 97%-99% TCE removal with 5%-20% quicklime dose. Quicklime treatment in sandy loam after 3 hours resulted in 79%-99% TCE removal with 5%-20% quicklime dose. Removal of TCE was retarded by high clay content when a 5% quicklime dose was applied. The data from these experiments confirm that under open conditions volatilization was primarily responsible for pollutant removal. Under closed conditions, decomposition increased. Under closed conditions, the volat ilization removed more contaminant than the decomposition. In addition, it was possible to re duce unwanted byproducts by increasi ng the soil moisture. Ko also evaluated the effects of soil particle size on the efficacy of quicklime treatment. Ko found that loamy sand required more quicklime to remo ve contaminant than the sand and sands with a high fraction of organic content. Ko determined that the production of byproducts increase when exposed to hydrated lime rather than qui cklime. The primary organic byproducts of decomposition of TCE and cisdichloroethylene (DCE) were dichloroacetylene (DCA) and chloroacetylene (CA). Under the most optimum conditions (TCE directly applied to hydrated quicklime without soil) up to 37% of TCE can be decomposed but only 0.3% of tetrachloroethylene (PCE) is decomposed. He al so concluded that other secondary byproducts likely formed but were unstable in the presence of air. The presence of excess water hinders the decomposition of TCE.

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25 Table 2-1. List of Hazardous Volatile Orga nic Compounds (US Environmental Protection AgencySW-846) Compound CAS Number Liquid Density Vapor Density SCTL Direct Exposure Residential (mg/kg) Perchloroethylene-Tetrachloroethylene 127-18-4 1.6 5.8 8.9 1,1,2,2-Tetrachloroethane 79-34-5 1.6 5.8 0.7 1,1,2-Trichloroethane 79-00-5 1.4 4.6 1.3 Carbon tetrachloride 56-23-5 1.6 5.3 0.4 Chloroform 67-66-3 1.5 4.1 0.4 Methylene chloride 75-09-2 1.3 2.9 16 Trichloroethylene 79-01-2 1.5 4.5 6.4 1,1,1-Trichloroethane 71-55-6 1.3 4.6 400 1,2,3-Trichloropropane 96-18-4 1.4 5.1 0.01 Ethylene dichloride 107-06-2 1.2 3.4 0.5 1,2-Dichloropropane-Propylene dichloride 78-87-5 1.2 3.9 0.6 1,1-Dichloroethane 75-34-3 1.2 3.4 290 Table 2-2. Examples of Remedial Action Treatment Technologies Soil In Situ Soil Ex Situ Groundwater In Situ Groundwater Ex Situ Bioremediation Chemical Reduction/Oxidation Barrier Walls Pump and Treat with surfactant Bioventing Critical fluid extraction Bioremediation Air stripping Capping Dehalogenation Chemical Reduction/Oxidation Carbon adsorption Soil flushing Excavation Hot water/steam flushing/stripping Chemical Oxidation/reduction Soil Vapor Extraction Incineration Natu ral attenuation Chemical treatment Solidification/Stabilization Land treatment Passive treatment walls Distillation Steam extraction Pyrolysis Sparging Membrane filtration Vitrification Slurry phase bioremediation Surfactants Precipitation Soil washing Reverse osmosis Solid phase bioremediation Solar detoxification Solidification/Stabilization Solvent extraction Solvent extraction UV oxidation Thermal desorption

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26 Table 2-3. Soil Cleanup Target Levels a nd Maximum Contaminant Level for TCE Direct Exposure Residential Commercial/ Industrial Leachability Based on Groundwater Criteria Contaminants mg/kg mg/kg mg/kg Maximum Contaminant Level (mg/L) Target Organs/Systems or Effects TCE 6.4 9.3 0.03 0.005 Carcinogen None specified Figure 2-1. Basic lithology of Fairbanks 30 Ft 60 Ft Sand Clay Hawthorne layer Land Surface

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27 Figure 2-2. Map of Fairbanks and contaminated site (FDOT, 2002).

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28 N N Figure 2-3. Map of contamination plume at Fairbanks (FDOT, 2002).

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29 CHAPTER 3 MATERIALS AND METHODS 3.1 Method Overview This material and method chapter is divided in to seven sections: 1) overview of methods, 2) soil information, 3) soil and test prepar ation, 4) sampling procedures, 5) analysis instrumentation, 6) experimental test vessel design, and 7) a st atistical data analysis using ANOVA F-test software. The research design and methods were developed to reflect the field circumstances found at the Fairbanks site. The sampling procedure was carried out in three distinct stages : 1) before adding quicklime, 2) 3 hours after adding quicklime, an d 3) 24 hours after adding quicklime. Chloride and TCE concentrations were collected at Stages 1 and 2. Stage 3 was reserved for the TCE concentrations after 24 hours. In addition, pH and temperature recordings were collected and observed during the reaction. Stage 1 represents the contamination-soil equilibrium period and establishes initial concentra tion. In Stages 2 and 3 the effects of the quicklime were documented. A sampling schedule with genera l timeline is illustrated in Figure 3-1. The analysis tested four soil types with va rious amounts of quicklime added (0%, 2%, 5%, and 10% by weight). The samples collected were in 18-inch stainless steel sampling tubes and then separated into three sections: a) 1-5 in ches (2.54-12.7 cm), b) 5-10 inches (12.7-25.4 cm), and c) 10-15 inches (25.4-38.1 cm). Each section was collect ed in triplicate. 3.2 Soil Selection and Information The soils used were collected from Pine Acres, Plant Science Research and Education Center at Citra, Florida and from New River Regional Landfill in Raiford, Florida. Three of the four soils tested were collected at Pine Acres: sand from the E-horizon, sand collected from the AE horizon (larger percent from the A-horizon) and a sandy clay loam from the B-horizon

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30 according to USDA classifications. The site has f our soil pits. At the bottom of these, the clay formation (Hawthorne) exists. The sandy clay loam was collected for this analysis from this clay layer. The soil pits were create d using an excavator, which made a vertical profile at a depth of approximately 7 feet. The soil master horizons were collected separately by using a hand shovel and scraping each soil horizon and placing larg e bins under each horizon to collect each soil type. A particle analysis a nd percent carbon analysis were pe rformed at the Soil and Water Science Department in Dr. Willie Harriss labora tory to classify each of the soil types. The sandy clay soil was collected from Raiford. Th e soil collected at the New River Regional Landfill in Raiford, Florida represents the highest pe rcentage of clay-size particle distribution in this study. The depth of soil to the clay hor izon was 8 to 10 ft bls. The landfill operator excavated and stored soils into large piles us ed as landfill daily cover material. The soil was broken up and worked by heavy machinery. The condition of that soil may reflect similar conditions at Fairbanks. Table 3-1 lists the particle dist ribution of the four types of so il tested. The sandy material was collected from the E-horizon and A/E-horizo n. The sandy clay loam was collected from the B horizon. The taxonomy of soil collected from Pi ne Acres is a Loamy Siliceous Hyperthermic Aquicarenic Paleudult. The soil series was a SPA RR and the soil order was Ultisols. Soil data analysis was performed in the Soil and Water Sc ience Mineralogy laboratory supervised by Dr. Harris. After drying, particle size distribution analysis was performed according to the Soil Survey Staff Method. All so ils were oven-dried at 105 C and water content was adjusted to 10%. 3.3 Experimental Apparatus Vessel-Drum The two test vessels are mass produce drums purchased from Zorin Materials (Waukegan, IL USA). The drums were 27 inches tall and 14 inches in diameter (68.58 cm by 35.56cm) made

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31 out of stainless steel. To allow gas to leave the system, the lid of the drum was modified to include three bungholes each with a -in inside diameter with NP T threading. To establish an initial concentration and to reach phase equi librium, the drum bungholes were capped during the equilibrium period. During the slaking proce ss, the bunghole caps were removed and covered with a screen mesh, allowing the vapor pressure to leav e the drum and also preventing the soil from exiting during end-over-end rotation. A locki ng lever secured the lid of the drum. An OAKTON thermometer probe was used to record temperatures. The stainless steel probe was inserted into the center of soil. The probe is approximately 7 inches l ong. A representation is illustrated in Figure 3-2. 3.4 Test Preparation and Initial Soil Sample Before testing, 50 kilograms of soil was oven-dried at 105 C for 24 hours or until the weight of soil held constant. The soil was then removed from the oven to allow the temperature of the dried soil to retu rn to ambient condition. The soil was weighed with a bench scale made by Mettler-Toledo SB12001, Columbus, Ohio. De-ioni zed water (free of ch lorine) was used to adjust the water content of all so ils tested to 10% of the total we ight of the dried soil (soil 50kg and water 5kg total) to allow for comparis on by soil texture. In addition, 50.642 g of trichloroethylene was added to each test for each analysis regardless of soil type to achieve a constant contamination level (Mettler-Toledo AE-260, USA). The test materials (soil, water, and TCE (Alfa Aesar, 99.5%)) were plac ed in the test vessel in five equal layers to create a more uniform distribution of water and the contaminant TCE within the soil before mixing. First,10 kg of so il were added, followed by 1 kg of DI water. After the DI water was absorbed into the soil 10.1284 g of TCE was added. This procedure was repeated four additional times to create five iden tical soil layers. After the soil, water, and TCE were completely applied, the soil depth was r ecorded. The amount of TCE added was calculated

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32 to reach an equilibrium concentration of 500 ppm. The equilibrium concentration, including the TCE vapor pressure in the sand, the TCE in the headspace (over sand), and the TCE in the voids within the soil space, was calcula ted using the ideal gas law at 25 C presented below in equation 3-1. In addition, the researcher developed an Excel worksheet to predict the volume of TCE necessary to spike the entire drum at 500 ppm listed in Appendix C. RT p V n Cg g g [3-1] gC : gas phase concentration of the compound gn : mole of the compound in gas phase gV : volume of the gas T : temperature (K) R : gas constant The test vessel was then placed on a verti cal drum rotator (Morse Mfg. Syracuse, NY. USA 1-300) and rotated 20 times end over end. The degree of mixing the materials was acceptable because of the adequate headspace in the drum. The time and temperature were recorded. After the rotation, th e sealed drum was undisturbed for 3 hours to allow the TCE to reach equilibrium throughout the soil and headsp ace of the drum. The drum was then opened and initial soil samples were collected for analysis as listed in Table 3-3. The following procedure used for sampling: Eighteen-inch JMC (Newton, IA USA) dry stainless steel sampling tubes were used to collect soil samples from the testing vessel with minimal loss of volatile compounds. The soil samples were collected in 42-mL EPA VOA vials. The vials were pre-measured and label. Nine vials were filled with 25 ml of DI water for decomposition analysis and 10 vials were fille d with 30 mL of methanol for to measure TCE concentration (VOA Vials, Fisher Scie ntific, Pittsburgh, Pennsylvania, USA).

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33 To reduce the loss of the volatile portion of the sample, the so il samples were calculated by subtracting the initial weight before and after soil sample collection which varied between 15g-30g for chloride ion analysis and TCE concentration. A correction factor was used to adjust for differences in sample sizes. In addition, samples of approximately 70g were collected for soil pH determination in EPA VOA vials. The collected samples were divided into three groups from the sampling tubes. The pH samples were collected randomly as a composite sample from each of the sections. Figure 3-3 represents the actual spacing of Sections A-B-C. 3.5 Quicklime Addition and 3and 24-Hour Sampling Event The quicklime used for this experiment (ON chemicals, Tampa Fl. USA) was of commercial grain size and stored in sealed 5-ga llon buckets. Each soil type was treated with four levels of quicklime application: 0% No Treatment 0.0 g CaO 2% Treatment 1101.1 g CaO 5% Treatment 2753.5 g CaO 10% Treatment 5505.1 g CaO Equation for 5%CaO dose (wet weight basis): ) 642 50 %) 10 ( 50 ( % gTCE kg CaO *.05= 2753.5 g Quicklime was added to the drum immediately after the initial soil samples were obtained and the time and initial drum temperature were recorded. The drum was then rotated again, mixing the quicklime into the soil. While the quicklime was added and mixed, the bungholes of the drum remained opened to release pressure created by the exothermic reaction during testing to maintain constant pressure during reaction. The temperature of the reaction was then recorded in 2-minute intervals for 30 minutes. Soil sample s for chloride and TCE analysis were then obtained 3 hours after the addi tion of quicklime. The drum wa s then returned to testing

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34 conditions until the next sampling event. Fina l soil samples were obtained 24 hours after the quicklime was added. In this sampling event, 10 FID samples were collected to measure the TCE concentration. Table 3-4 lists the samples taken during this sampling event. 3.6 Analysis Instrumentation Following collection, soil samples for TCE and chlorine analysis were mixed end over end for 2 hours to facilitate extraction. Th e TCE samples were then stored below 4 C. Before analysis the samples were filtered with .2m syringe Teflon filters and the chloride samples were filtered using vacuum filtration with 0.45um filte rs. The contaminant concentrations of the filtered samples were analyzed on a gas chroma tograph/flame ionization instrument (GC/FID, Hewlett Packard 5890 Series II) and decompos ition chloride product was analyzed using a DIONEX LC20 Ion Chromatograph. The IC was operated with 1.20 mL/min of effluent flow rate through an Allsep Anion 7u column (Alltech, Deerfield, Illinois, USA). 3.7 Statistical Analysis Software ANOVA Statistical analysis was used extensively to determine the variation of TCE and chloride levels before and after treatment. The software is single-factor analysis using a 95% confidence interval. The principal factor for determining wh ether the populations are different is to compare the F value and the F critical value. If the F valu e is larger than the F critical, the populations are significantly different. In addi tion to F values, p values are generated using the ANOVA software. If critF F than the difference is significant [3-2] In addition to F values the software created P-va lues. Appendix D is list of the tables used to determine if populations we re statistically similar.

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35 Table 3-1. Particle Texture Distribution Particle Category Sand E Sandy Clay Loam Sandy Clay Sand AE % Sand 95.9 76.4 62.0 96.4 % Silt 2.3 5.7 6.1 1.7 % Clay 1.8 17.9 31.9 1.9 Table 3-2 Organic Carbon Data Organic Carbon Sand E Sandy Clay Lo am Sandy Clay Sand from A/E % Carbon 0.306 0.309 0.323 0.997 % Carbon 0.316 0.312 0.361 0.874 Standard Deviation 0.007 0.002 0.027 0.087

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36 Figure 3-1. Sampling schedule of soils tested Soil Synthesis Treatment Final Soil Sampling 0 Hour Sample 3 Hour Sample 24 Hour Sample Collection, Drying, Adding 0%,2%,5% Analysis: TCE, Chloride p H

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37 Table 3-3. Sampling Inventory for Initial Soil Samples Table 3-4. Summary of Sample Method Inventory after 3 Hours Analysis Frequency of Samples Solvent Weight of Samples pH 2 None 50-70 g Chloride Analysis 6 25 ml of DI water 20-30 g Gas Chromatograph TCE 10 30 ml of Methanol 10-20 g Analysis Frequency of Sample sSolvent Weight of Samples pH 2 None 50-70 g Extractable Chloride: IC 9 25 ml of DI water 20-30 g TCE: GC/FID 10 30 ml of Methanol 10-20 g

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38 14 inches Stainless Steel Construction Teflon O-ring Seal 27 inches Vapor in Headspace Removable Lid Air ti g ht Contaminated Soil Figure 3-2. Schematic of Drum Te st Vessel (not drawn to scale)

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39 Figure 3-3. Sampling Tube and Layer Delineation

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40 CHAPTER 4 RESULTS AND DISCUSSION 4.1 Temperature Profiles with Quic klime addition and Soil Texture Figures 4-1, 4-2, and 4-3 present the temperat ure profiles for each of the four soil types but with the quicklime dose varying (2%, 5%, and 10%) The temperature profile with no quicklime was left out because the conditions we re stable at ambient temperatures. 4.1.1 Temperature Profiles in soils with 2% Quicklime Addition Figure 4-1 depicts the temperat ure profiles in all soil type s with the addition of 2% quicklime by weight. Beginning near 24 C 3 C sand E, sand AE, and sandy clay loam, soil temperature quickly increased above 33 C within the first 5 minutes This did not include sandy clay. Sandy clay soil temperatur es experience a long and steady in cline. The probable cause for delayed temperature peaks in sandy clay is that clays generally contain a higher percentage of finer materials than do sandy soils. This is par tially explainable since the availability between quicklime and soil moisture is reduced in finer grain materials. Anothe r possible reason for the lag is poor mixing. As previously discussed, larger pieces of th e material in clay soils reduced the ability to mix the quicklime into the materi al. By comparison, the sand E horizon with adequate mixing experienced the most accelerated temperature spike among the soil types. In addition, the heat within the sand E persists longer. This trend is also appa rent in Figure 4-2 and Figure 4-3. This trend may be a possible reason why sand E consis tently contains the largest reduction of TCE. 4.1.2 Temperature Profiles in soils with 5% Quicklime Addition As Figure 4-2 shows, soil temperatures were much higher in the 5% quicklime addition than in the 2% quicklime addition. By comparison with the 2% quicklime application, the average maximum temperature peak from all soil types achieved was 43 C 1 C, the maximum

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41 temperature achieved in the 5% quicklime additio n for all soil types tested increased to 81 C 1 C. The sandy clay soil temperature profile ag ain was the slowest to increase; however, it reached the highest soil temperature (92 C) among the soils tested. The sandy clay loam reached the next highest temperature at 87 C. Both of the soil types with high sand content had lower temperatures of 70 C and 74 C for sand E and sand AE, respectively. There may be a relationship between water consumption in the quicklime reaction and higher temperatures illustrated in the soils with higher clay content. 4.1.3 10% Quicklime Addition and Temperature Profiles On average, the difference between 5% and 10% CaO doses resulted in a 20 C increase in all soils. The 10% quicklime a pplication produced the highest temperatures among the four quicklime doses. The difference in temperat ures peaks among larger quicklime (5% and 10%) doses becomes less severe. The difference on average from the 2% to the 5% application was 40 C and by comparison the difference between 5% and 10% quicklime application is only 20 C. Again Figure 4-3 shows that the sandy clay temperature peak is delayed and contains the maximum temperature peak. This trend is consis tent for soils tested with quicklime addition. In summary, soil temperatures increased quick ly between 5 and 15 mi nutes after quicklime addition with subtle changes de pending on soil type. Temperat ure in sands increased faster while soils higher in clay content took more tim e to reach maximum temperature. Sandy clay soil consistently reached the highe st temperatures. The difference of temperature rise in coarse sand E and sandy clay was likely caused by the differe nt fraction of finer pa rticles in soils that had larger surface area and a strong affinity to water. The sand E soil type consistently retains heat longer than the other soil types. Compared with the experiments conducted in the small-sc ale research, the maximum temperature achieved was greater in the laboratory experiments. Thes e higher temperatures may have been attributed

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42 to higher quality of quicklime, a finer grade of quicklime (better mixing), and over all better mixing of materials. In Section 4.2, the conne ction between maximum te mperature achieved and total TCE removed is limited. 4.2 Impacts of Soil Textures on TCE Removal with Quicklime Addition Figures TCE concentration can be examined in two stages, before and after addition of quicklime (Figure 4-4 through Figu re 4-7). The first graph (A) of each figure represents the initial concentration of TCE fo r each analysis and the second gr aph (B) represents the final concentration of TCE after 24 hours with the addition of quick lime, excluding Figure 4-4 where no quicklime was added. Vertical Box plots were chosen because of the high variability of TCE concentrations. Each box plot represents the TCE concentration of 10 samples. 4.2.1 TCE Concentration with No Quicklime Application Figure 4-4 A represents the initial TCE concen trations tested after a 3-hour equilibrium period in four soil types. The initial con centration of TCE varies between 100-400mg/kg. Individual samples were found to contain concen trations greater than 1000 mg/kg and less than 100 mg/kg. As evident in Figure 4-4 A, the ini tial TCE concentrations for all soils possess a large degree of variation. The exception is sa nd AE, which contains le ss variation in initial concentration as illustra ted in Figure 4-4 A. Figure 4-4 B depicts the volatili zation of TCE from the drum after 24 hours of natural (spontaneous) volatilization without the addition of quicklime. The associated P-value, from the sand E, sandy clay loam, and sandy clay, is 0.29 and statistically the same (See Appendix D). The sand AE (.87 carbon content) was significantly different after 24 hours from the other three soil types tested. Performing F-test analysis confirms that the data from the sand AE is significantly different.

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43 The average concentrations of TCE remained were 15.3 mg/kg, 8.4mg/kg, and 18.02 mg/kg in sand E, sandy clay loam, and sandy clay, respectively. The aver age concentration of TCE for the sand collected from the AE master horizon was much higher, 127.8 mg/kg (Standard deviation 41.8 mg/kg). The sandy clay, which co ntains the highest percent of clay (32%), contains the next highest concen tration after 24 hours. The data suggest that soils associated with low surface area, such as sands, and soil w ith low levels of organic matter (<31% clay fraction) will more easily release contaminant fr om the system. This effect may possibly be a result of less sorption of TCE to the organic fr action. Furthermore; the TCE volatilization in sands compared to materials with finer particles will have less interfacial tension. Soils with high interfacial tension and str ong capillary forces may retard volatilization of contaminant. 4.2.2 TCE Removal with 2% Quicklime Application Figure 4-5 illustrates the effect s of adding quicklime doses of 2% by weight to four soil types. Initial concentrations were similar among the four soil types. Adding 2% quicklime resulted in removing more than 90-95% of the initial TCE for a ll soil types tested, as shown in Figure 4-5. However, the 2% Ca O application only resulted in a 5% increase in TCE removal. The average concentration after 24 hours extrac ted varied between 5.8 9.3 mg/kg of TCE. However, due to the high initial concentrations 2% application did not consistently remove enough TCE to pass the target le vel residential direct expos ure SCTL limit of 6.4 mg/kg (GWTCL limit 0.03 mg/kg). The final TCE concen trations after 24 hours did not significantly vary among the soil types tested excluding the te st in sand AE. The 2% quicklime application was effective for sand E and sandy clay loam soil types. 4.2.3 TCE Removal with 5% Quicklime Application Figure 4-6 presents the results of the addition of 5% quick lime. The TCE concentration for all soil types in the 5% CaO application was significantly reduced and consistent. The results

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44 did not vary significantly by soil ty pe. The P-value for all the data after quicklime addition of 5% is 0.34, which passed the F-test analysis. The statistic summary is listed in Appendix D. The effects of quicklime at 5% overcame the effects of soil texture and organic matter in all soils tested. However, sand with high organic content a nd soils with higher clay content lost less than the other two soil types. In sand E and sandy cl ay loam, the TCE concentrations were lowered sufficiently. They both showed lower levels set by the residential direct exposure SCTL standard requirements, as illustrated in Figure 4-6. 4.2.4 TCE Removal with 10% Quicklime Application The application of 10% CaO resulted in similar TCE removals compared to the 5% quicklime application. Initial concentrations were similar with respect to the average initial conditions. However, the sandy clay initial were on average, lower with an average initial concentration of 77 mg/kg. The results indica te that the sandy soils lose more TCE after 24 hours than sandy clay soil. Several soil sample s from sand E and sandy clay were above the target level and required further remediation. The analysis cannot be directly compared to the results from the 5% application because the init ial concentrations of TCE are different between analyses. Most of the samples collected from the sand AE and sandy clay loam analysis would not require further treatment. The sandy clay co ncentrations were higher than the other soil types. A statistical analysis determined the sandy clay concentrations to be significantly different with a P value of 0.0032, which fails the F-Test. However, a complete statistical analysis comparing the results am ong all soil types was performed. The results of this test also confirm that final TCE concentrations are signi ficantly different with a P-value of 0.0084. Appendix D provides a st atistical summary. Figure 4-8 is a summary of TCE removal in all soil types tested and at each sampling interval, 3 and 24 hours. In addi tion, from Table 4-1 it is clear from this graph that the TCE

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45 concentration did not change to a great extent between the 5% and 10% application. The TCE concentration in the 5% quicklime application was lower than in the 10% quicklime application. Comparing TCE concentrations at 3 and 24 hours, 3 hours is a sufficient time to allow contaminant to be removed. In general, the amount of TCE increased from 0%-2%-5% quicklime addition. This trend did not cont inue at the 10% quicklime application. The removal of TCE at 24 hours from 2% qui cklime dose removes 90% of contaminant in soils with initial concentrat ion between 300-400 mg/kg. A 5% quicklime dose can remove 95% percent of TCE. Although the difference is not la rge, the impacts could be crucial in terms of meeting SCTL and GWTCL. The data suggest th at an application of 5% quicklime among the quicklime doses used is sufficient to remediat e TCE-contaminated sandy soils. Additionally, soils with higher percent of clay (> 30% clay ) may require at least 10% to meet the same treatment levels. The differen ce of volatilization betw een the 3and 24-hour sampling events was not significant with most tests. The data suggest that most of the contaminant volatilizes quickly (before 3 hours, as Table 4-1 shows). With respect to managing a field application, the quicklime treatment will usually work well in sandy soils due to good mixing and low su rface charge. In terms of the quantity of quicklime necessary, sandy soil requires less and so ils higher in clay content may require higher doses of quicklime to reach target cleanup levels. A field-scale ap plication would require adding a larger percent of quicklime because the rema ining TCE in the soil is still above SCTLs. However, if the degree of mixing of quicklime and soil is increased, the amount of quicklime necessary may be reduced. The variation in in itial TCE concentration limits the ability to accurately define the optimum quicklime dose. One reason for the variation is the sampling procedure. The effects of sampling must be co nsidered as a potential pathway of contaminant

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46 loss due to the increase of exposed surface area. Another reason in itial concentrations vary is that the degree of mixing varies because the init ial conditions of the soil sampled varied. The sand was very lose and mixed very well. Visually the soils higher in clay did not mix as well. In addition, the time to reach equilibrium may vary depending on the soil texture. 4.3 TCE Removal with Depth of th e Quicklime-Treated Materials Figures 4-9 A-D present the av erage initial concentration of TCE and final concentration after 3 hours. The data for the 24 hours are listed in Appendix A. The concentrations in the sand E are representative of the typical trends, althou gh some exceptions do exist. Notably, the TCE concentration increases as a function of soil depth. In the sand E soil, TCE concentrations in the bottom soil layer are three times greater than in the top soil layer. The difference between the top and middle layer was not si gnificant (less than 5%). The TCE concentrations observed for a 10% quicklime dose in the sand A/E soil and sandy clay highlight the differences between depths, with TCE below detectab le levels in the upper layer and increasing with great er depths. As the soil depth increases, the potential for volatilization from the soil decreases due to the gr eater distance for transport to the atmosphere. The exceptions contained within the graphs are due to the relative heterogeneity of the TCE distribution. Within soil, TCE often remains in the liquid phase and in concentrated pockets. Therefore, random sampling of a soil w ill contain varying quantities of TCE. An increased soil column resulted in consistently higher concentrations of TCE near the base of the drum (10-15in) independent of soil texture type. However the difference between the top and bottom concentrations of TCE was not statistically significant; this trend was consistently observed. Based on these results, contaminant removal would be more effective if the soil depth is limited to 15 inches. Increase d soil depth may affect contaminant transport, mixing, and volatilization; these factors would be important to examine in future studies.

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47 4.4 Chloride Analysis with Respect to Soil Depth The decomposition analysis was important as pect of this research because it may determine if there is a possibi lity to form new and potential ly more toxic compounds created through dechlorination of TCE. The chloride concentrations from th e four soil types are displayed in Figure 4-10 to Figur e 4-13. To determine if decomposition or dechlorination was occurring with quicklime application, chloride ions were extracted from the soil samples. The chloride concentrations after qui cklime addition did not increase significantly above the initial chloride concentrations. The av erage initial concentration in the sand E soil was 3.1 mg/kg 1.9 after quicklime the average final concentration for 0%, 2%, 5%, and 10% was 4.4 mg/kg 2.0, 3.6 mg/kg 0.7, 5.7 mg/kg 1.7, and 1.8 m/kg .3 respectively. Additionally, the initial and final concentrations did not in crease or decrease for the sand AE soil upon adding quicklime. However, in the sandy clay loam and sandy clay soil soils, the chloride concentration decreased after quicklime addition on average. The chloride decrease in the sandy clay loam ranged from 56%-98% reduction after quicklime The chloride decrease in the sandy clay ranged from 37%72% reduction after quicklime. The chance for decomposition may be limited as a result of high volatilization rates discussed in previous sections It is expected that enough volatilization oc curred to reduce potential for decomposition. However, an incr ease of chloride does not directly indicate decomposition or formation of new compounds occurs but if an increase of chloride was present it suggests the conditions are such that decomposition is possible. In future research, an analysis that studies reaction between chloride ions and product from quicklime reaction would be useful to qualify if decomposition is occurring.

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48 4.5 Soil pH Analysis Table 4-2 summarizes the pH observed in each soil type before and after quicklime treatment. As seen in the previous secti ons, quicklime treatment resulted in a significant reduction in TCE concentrations within the larg e-scale experiments. However, most of the treated soils retained enough contaminant after 24 hours to require further treatment to meet regulatory cleanup targets. Extension of the trea tment time may result in further reductions in contaminant concentrations. Reapplying water to the soil may also prove to further remediate the soil by further volatilizing a nd adding a secondary benefit of lo wering the pH of the soil.

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49 Minutes 1101001000 Degree Celsius 20 25 30 35 40 45 50 Sand E Sand AE Sandy Clay Loam Sandy Clay Figure 4-1. Two-percent quicklime addition and soil temperature r ecordings in Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. Two-mi nute intervals for 30 minutes, 180 min, and 1440 min.

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50 Minutes 1101001000 Degree Celsius 20 30 40 50 60 70 80 90 100 Sand E Sand AE Sandy Clay Loam Sandy Clay Figure 4-2. Five-percent quicklime addition and soil temperature r ecordings in Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. Two-mi nute intervals for 30 minutes, 180 min, and 1440 min.

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51 Minutes 1101001000 Degree Celsius 20 30 40 50 60 70 80 90 100 110 120 Sand E Sand AE Sandy Clay Loam Sandy Clay Figure 4-3. Ten-percent quicklime addition and soil temperature r ecordings in Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. Two-mi nute intervals for 30 minutes, 180 min, and 1440 min.

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52 sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 100 200 300 400 500 600 1200 1400 1600 A. Initial sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 20 40 60 80 100 120 140 160 180 200 220 B Final Figure 4-4. TCE concentration at 0 Hours (A) and TCE concen tration after 24 Hours (B) No quicklime added to Sand E, Sand AE, Sa ndy Clay Loam, or Sandy Clay. The middle bars 90th percentile. The TCE was extracted using methanol and is expressed in mg/kg of soil

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53 sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 100 200 300 400 500 600 A. Initial sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 5 10 15 20 25 30 35 40 B. Final Figure 4-5. TCE concentration at 0 Hours (A) and TCE concen tration after 24 Hours (B) 2% quicklime added to Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. The middle bars represent the 90th percentile. TCE was extracted using methanol and is expressed in mg/kg of soil.

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54 sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 100 200 300 400 500 600 700 800 900 1000 2400 2600 A. Initial sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 5 10 15 20 40 50 60 B. Final Figure 4-6. TCE concentration at 0 Hours (A) and TCE concen tration after 24 hours (B) 5% quicklime added to Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. The middle bars represent the 90th percentile. TCE was extracted using methanol and is expressed in mg/kg of soil.

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55 sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 100 200 300 400 500 600 700 800 900 1000 1100 A. Initial sand Esand AEsand clay loamsandy clay TCE (mg/kg) 0 5 10 15 20 B. Final Figure 4-7. TCE concentrati on at 0 Hours (A) and TCE c oncentration after 24 (B) 10% quicklime added to Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. The middle bars represent the 90th percentile. TCE was extracted using methanol and is expressed in mg/kg of soil.

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56 Table 4-1. TCE removal in four soil types with respect to quicklime applications Soil Type and Quicklime Dose 0% SD 2%SD 5%SD. 10% SD Sand E horizon % Removal 3 Hours 86 974797298 1 % Removal 24 Hours 91 797599097 3 Sand A/E horizon. % Removal 3 Hours 50 308810963100 0 % Removal 24 Hours 57 1397498299 1 Sandy Clay Loam % Removal 3 Hours 81 1796299299 1 % Removal 24 Hours 97 2981100098 1 Sandy Clay % Removal 3 Hours 0 08313851167 43 % Removal 24 Hours 89 15965941393 6 SD is the standard deviatio n* All percent are rounded

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57 TCE Concentration (mg/kg) 1 10 100 1000 Initial TCE Concentration TCE 3 hours TCE 24 hours 1 10 100 1000 1 10 100 1000 Sand ESand AESandy Clay LoamSandy Clay 1 10 100 1000 2% CaO dose 0% CaO dose 5% CaO dose 10% CaO dose Figure 4-8. Summary of TCE removal in all soil types with respect to time.

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58 0-5 in5-10 in10-15 inTCE (mg/kg) 1 10 100 1000 0% Quicklime 2% Quicklime 5% Quicklime 10% Quicklime A Figure 4-9 TCE concentration after 3 hours with re spect to soil depth af ter quicklime addition. The dotted line is the initial concentration before quicklime is added (0 Hour). The error bars indicate standard deviation. (A) Sand E; (B) Sand AE; (C) Sandy Clay Loam; (D) Sandy Clay. 0-5 in5-10 in10-15 inTCE (mg/kg) 1 10 100 1000 0% Quicklime 2% Quicklime 5% Quicklime 10% Quicklime B

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59 0-5 in5-10 in10-15 inTCE (mg/kg) 1 10 100 1000 0% Quicklime 2% Quicklime 5% Quicklime 10% Quicklime C 0-5 in5-10 in10-15 inTCE (mg/kg) 1 10 100 1000 0% 2% 5% 10% D Figure 4-9. Continued

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60 0-5 in5-10 in10-15 inChloride (mg/kg) 10 20 30 40 50 0% CaO 2% CaO 5% CaO 10% CaO Initial Chloride Figure 4-10. Sand E. Decomposition of TCE chl oride ions with respect to soil depth and quicklime addition. Nine soil samples we re collected, three at each depth. Soil samples were collected 3 hours after quickli me addition. The dotted line represents the chloride concentration before quicklime a ddition. Chloride was extracted with DI water.

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61 0-5 in5-10 in10-15 inChloride (mg/kg) 10 20 30 40 50 0% CaO 2% CaO 5% CaO 10% CaO Initial Chloride Figure 4-11. Sand AE. Decompos ition of TCE chloride ions w ith respect to soil depth and quicklime addition. Nine soil samples we re collected, three at each depth. Soil samples were collected 3 hours after quickli me addition. The dotted line represents the chloride concentration before quicklime addition. Chloride extracted with DI water.

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62 0-5 in5-10 in10-15 inChloride (mg/kg) 10 20 30 40 50 0% CaO 2% CaO 5% CaO 10% CaO Initial Chloride Figure 4-12. Sandy Clay Loam. Decomposition of TC E chloride ions with respect to soil depth and quicklime addition. Nine soil samples we re collected, three at each depth. Soil samples were collected 3 hours after quickli me addition. The dotted line represents the extractable chloride concentration be fore quicklime addition. Chloride was extracted with DI water.

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63 0-5 in5-10 in10-15 inChloride (mg/kg) 10 20 30 40 50 0% CaO 2% CaO 5% CaO 10% CaO Initial Chloride Figure 4-13. Sandy Clay. Decomposition of TCE c hloride ions with respect to soil depth and quicklime addition. Nine soil samples we re collected, three at each depth. Soil samples were collected 3 hours after quickli me addition. The dotted line represents the extractable chloride concentration be fore quicklime addition. Chloride was extracted with DI water.

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64 Table 4-2. pH Summary of adding quicklime to four soil types: Sand E, Sand AE, Sandy Clay Loam, and Sandy Clay. Sand No Treatment 2% CaO 5% CaO 10% CaO Dried Soil 5.19 5.72 6.22 5.53 Wet Soil + TCE 5.37 5.42 6.16 5.55 Wet Soil+TCE+ CaO 5.75 11.68 11.59 11.20 Sand High Organic No Treatment 2% CaO 5% CaO 10% CaO Dried Soil 5.03 4.34 5.48 5.48 Wet Soil + TCE 5.59 4.48 5.46 5.56 Wet Soil TCE CaO 5.97 11.41 11.68 11.64 Sandy Loam Clay No Treatment 2% CaO 5% CaO 10% CaO Dried Soil 3.89 4.75 3.65 5.53 Wet Soil + TCE 3.82 4.51 4.44 5.53 Wet Soil TCE CaO 3.86 11.40 11.50 11.20 Sandy Clay No Treatment 2% CaO 5% CaO 10% CaO Dried Soil 4.66 4.74 4.45 4.34 Wet Soil + TCE 4.57 4.35 4.39 4.48 Wet Soil TCE CaO 4.91 11.87 10.70 11.41

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65 CHAPTER 5 CONCLUSIONS 5.1 Summary and Conclusions In this research, quicklime was applied to soils artificially contaminated with TCE. Using previous knowledge obtain from a small-scale laboratory analysis (K o, 2007), a large test vessel/drum was constructed to ev aluate the potential remediation t echnology. This research has three primary objectives: To determine if soil texture can impact qui cklimes ability to remove TCE from soilmaterial To determine if the amount of TCE remove d changes with soil depth as a result of quicklime application To determine if decomposition of TCE occurred in the test vessel and, if decomposition does occur, does depend on soil type Four soil types were tested with quicklim e applications of 0%, 2%, 5%, and 10% by weight and spiked with TCE. Each soil analysis consisted of 50 kg of soil and 5 kg of DI water. Chloride and TCE concentrations were quantified with respect to soil depth before and after quicklime addition at 3-hour and 24-hour sampli ng events. Three layers were artificially delineated within a large testing vessel for soil depth analysis. Soils with higher clay cont ent (30%) had a greater prope nsity to retain TCE after treatment. However, the clay content may have not been the primary cause for retention of TCE. Instead, because the sandy clay did not mix as we ll as the other soil types it may have lead to sporadic high concentrations of TCE. Large ar tificial chunks were present in the sandy clay and appeared to decrease the ability to evenly dist ribute the materials thr oughout the test vessel. Hence, a large degree of varia tion (24 hr TCE 9 19 mg/kg with 5% quicklime addition) of TCE concentration was observed in th e sandy clay. In the samples co llected in the sandy clay at 24 hours, eight of the 10 samples contained TCE c oncentration below 2.5 mg/kg. However, two

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66 samples contained 21 and 60 mg/kg. Sand E and sa ndy clay loam were the most susceptible to the quicklime technology among the soil tested. Two possible reasons for this result are the good mixing conditions and because the sands are known to have low surface charge. Based on the research provided, a 10% qui cklime dose, despite producing the highest temperature (10% 86-111 C, 5% 70-92 C), did not significantly increase the amount of TCE removed compared to a 5% CaO dose. Thus, temperature may be less in fluential than the proper mixing of materials. To meet the third objective, chloride was us ed to measure potential decomposition of TCE. The extractable chloride concen trations did not incr ease with quicklime. The low chloride concentration compared with the initial chloride concentration after quicklime addition indicates that decomposition was negligible. This resu lt was consistent in all soil types tested. In summary there are important conclusions and observations based on this research: Soil temperature increased quickly after 5-15 min but the change of temperature varied with soil type. Temperature in sands increase d faster while soils higher in clay content took more time to reach maximum temperature. Sandy clay soil consistently reach ed the highest temperatures. The difference of temperature rise in coar se sand and sandy clay was likely caused by the different fraction of finer partic les in soils that ha d large surface area and a strong affinity to water. Comparing TCE concentrations of 3-hours-treated soil to 24 -hours-treated soil, TCE in soil treated for 3 hours did not varied with those treated for 24 hours. The amount of TCE removed in creased from 0%-to 2%-to 5% quicklime application. The removal of TCE occurs to a greater extent ne ar the top of the test vessel rather than at the base. It is recommended that the soil prof ile be limited to 15 to 18 inches in depth. A volatile removal of TCE for 24 hours from 2% CaO dose removes 90% of TCE in soils with initial concentration of 300-400 mg/kg. A 5% CaO dose removes 95% of TCE. TCE concentrations after 24 hour-treatment did not significantly vary among the soil types tested, excluding the test in sand AE test Overall the impacts of soil type affecting the removal of contaminant with 2% quicklime doses were minimal except with soil rich in organic matter.

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67 The data suggests that 5% application of quick lime is sufficient to treat sandy soils. In addition, soils with higher clay content (> 30% clay) may require at least 10% quicklime to meet soil target levels. For removing TCE up to 95% of initial TCE in all types soils tested within 24 hour-treatment, the optimum amount of quicklime was 5% (by weight) of soil. The differences between TCE concentrations treated for 3 hour and 24 hours were similar except the sandy clay. A 5% quicklime additi on at 3 hours resulted in an 87% removal and a 95% removal at 24 hours. A 10% quick lime addition at 3 hours resulted in a 39% removal and an 87% removal at 24 hours. The chloride concentration did not incr ease as a result of quicklime addition. Furthermore, decomposition did not occur to a greater extent with respect to soil type. 5.2 Limitations, Implications, and Recommendations The ability to remove contaminant is unique to the soil type at lower doses of quicklime (2%). Sand E and sandy clay loam were the most susceptible to using quicklime for remediation of TCE-contaminated soil. However, soils high in clay content (>31%) and soils with organic matter greater than 1% can be treated with quick lime given adequate mixing and soil heights that do not exceed 15 inches. Soil depth is another fact or that could potentially affect remediation success. If the soil depth to be treated exceeds the ability to properly mix the quicklime into the soil, the ability of quicklime to react with soil moisture may be compromised. Thus deeper soil depth would lead to lower temperatures due to poor mixing. Increased soil depths could be possible in sandy soils. Another way to increase remediation efficiency would be limiting soil depth to be treated less than 18 inches (46 cm). Further studies invest igating soil depths would be useful to determine a suitable area for remedia tion. In future studies, optimum water content for individual soil types woul d increase the economics in te rms of amount of quicklime necessary to remove contamination below thresh old levels. Another way to better understand quicklime as a treatment is to apply it to a sour ce of contamination from an actual field site. Additional studies would benefit from acquiri ng soils where natural attenuation of the contaminant has occurred. In this study pure TCE was used as the contaminant. The original

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68 chemical would likely have several species form ed by microbial activities in the soil before excavation. Quicklime technology proved to remove TCE fr om soils and thus is viable ex-situ remediation strategy with limitations. Decompositi on of TCE did not occur near the base of the testing vessel. However, to ensure safety re mediation plans should incl ude a protective barrier under the area of treatmen t in case a small amount of decomposition should occur. The protective barrier should be d eep enough to prevent exposure to heavy machinery associated with mixing of quicklime. A quicklime dose of 5% proved to be ade quate to significantly reduce (>98%) the contaminant. Multiple applicati ons of quicklime or water are ve ry possible with this technology and should be considered as an area of futu re research. Applyi ng water after quicklime application may increase the chance s for a reaction to reoccur. R eapplication could be a useful research topic. Overall, the main pathway by which the TCE is removed from the soils is volatilization through the use of quicklime.

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69 APPENDIX A COMPLETE LIST OF ALL DOCUMEN TED TCE REMOVAL ANALYSIS Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-1. Sand E 0% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 1 10 100 0-5 inches 5-10 inches 10-15 inches Figure A-2. Sand E 2% CaO Treatment

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70 Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-3. Sand E 5% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-4. Sand E 10% CaO Treatment

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71 Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 10-15 inches 10-15 inches Figure A-5. Sandy Clay Lo am 0% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-6. Sandy Clay Lo am 2% CaO Treatment

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72 Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-7. Sandy Clay Lo am 5% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-8. Sandy Clay Lo am 10% CaO Treatment

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73 Time Initial3 hour24 hour mg/kg of TCE 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-9. Sandy Clay 0% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-10. Sandy Clay 2% CaO Treatment

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74 Time Initial3 hour24 hour mg/kg of TCE 0.1 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-11. Sandy Clay 5% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 0.1 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-12. Sandy Clay 10% CaO Treatment

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75 Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 in 5-10 in 10-15 in Figure A-13. Sand A/E 0% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 inches 5-10 inches 10-15 inches Figure A-14. Sand A/E 2% CaO Treatment

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76 Time Initial3 hour24 hour mg/kg of TCE 1 10 100 1000 0-5 in 5-10 in 10-15 in Figure A-15. Sand A/E 5% CaO Treatment Time Initial3 hour24 hour mg/kg of TCE 0.1 1 10 100 1000 0-5 in 5-10 in 10-15 in Figure A-16. Sand A/E 10% CaO Treatment

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77 APPENDIX B CHLORIDE CONCENTRATION 0-5 in 5-10 in 10-15in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-1. Sand E-Horizon with No Quicklime Addition 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-2. Sand E-Horizon with 2% Quicklime Addition

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78 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-3. Sand E-Horizon with 5% Quicklime Addition 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-4. Sand E-Horizon w ith 10% Quicklime Addition

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79 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-5. Sandy Clay Loam with No Quicklime Addition 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-6. Sandy Clay Loam with 2% Quicklime Addition

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80 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-7. Sandy Clay Loam with 5% Quicklime Addition 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-8. Sandy Clay Loam with 10% Quicklime Addition

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81 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 10 20 30 40 Initial Final Figure B-9. Sandy Clay with No Quicklime Addition 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 20 40 60 80 100 Initial Final Figure B-10. Sandy Clay with 2% Quicklime Addition

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82 0-5 in 5-10 in 10-15 in Chloride ion mg/kg 0 20 40 60 80 Initial Final Figure B-11. Sandy Clay with 5% Quicklime Addition 0-5 in 5-10 in 10-15 in Chloride mg/kg 0 20 40 60 80 Initial Final Figure B-12. Sandy Clay with 10% Quicklime Addition

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83 0-5 in 5-10 in 10-15 in Chloride ion mg/kg 0 10 20 30 40 50 60 70 Initial Final Figure B-13. Sand AE-Horizon with No Quicklime Addition 0-5 in 5-10 in 10-15 in 1234567 Chloride mg/kg 0 10 20 30 40 Initial Average Figure B-14. Sand AE-Horizon with 2% Quicklime Addition

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84 0-5 in 5-10 in 10-15 in 0123456 Chloride mg/kg 0 10 20 30 40 Initial Average Figure B-15. Sand AE-Horizon with 5% Quicklime Addition 0-5 in 5-10 in 10-15 in 1234567 Chloride mg/kg 0 10 20 30 40 50 Initial Final Figure B-16. Sand AE-Horizon with 10% Quicklime Addition

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APPENDIX C EXCEL WORSHEET TO PREDICT TCE ADDITION

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86Table C-1. Excel worksheet us ed to calculate TCE volumes Trichloroethylene Volume CalculationDensity1.46 MW131.4g/mole Solubility1100mg/L Vapor Pressure74mmHg at 293K log Kow2.42 sand50.00kgBulk Density1.65g/cm3Volume of Sand30303.0cm3Specific Gravity2.65Porosity (n=Vvoid/VTotal)0.38Volume of Voids in sand (L)11435.1cm311.44 Water5.00kg wc 10% egeeo saturation (Sr=Vwater/Vvoid )0.44 Total55.00kg Total mass27500mg27.5gMass5500mg 5.50 g Total volume18836uL18.8mLVolume3767uL 3.8 mL Mass22000mg 22.00 g Volume15068uL 15.07 mL Chemical properties of TCE Mass of Soil and Water TCE in wet soil TCE as liquid phase (not dissolved) Properties of the sand TCE in Soil water at equilibrium

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87Table C-1. (continued) fy Diameter14inDepth27in Area of the bottom154in2993cm2 Vol. of Drum4154in368075cm368.1Liters Surface Area (Inside of the drum)1186.9in27134770cm2 Height of Sand in the drum30.5cm12.0in Vol. of Headspace2305.0in337772.5cm337.8Liters Vol. of unsaturated voids in sand6435.1cm36.4Liters Total Headspace 44219.6cm444.2Liters TCE in Head at 25OC Temp. (K)1/KTCE vapor pressure (mm Hg) at 25oCln p*ibarpaR (L.bar.mol-1.K1)(with pure TCE)2980.00336744.304070.0999865.90.0831 Cig=nig/Vg=P *i/RT mg/LTCE In the Headspace (over sand)TCE In the Headspace (voids in soil) Mass0.00398398523.519773.7mg 19.8 g3368.7mg 3.4 g Volume13543.6uL 13.5 mL2307.4uL 2.3 mL Ignored IgnoredThe amount of TCE that is required to synthesize 500ppmTCE soil by the phase equilibrium at 25oC Mass 50.6425g10.13volume 34.7mL TCE in Headspace at equilibrium Partitioning to Organic Matter Partitioning to Solid (sand + drum) Volume of the drum Sand in the drum TCE in Headspace at equilibrium

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88 APPENDIX D STATISTICAL SUMMARY Table D-1. Summary of TCE c oncentration mg/kg in Sand E, Sandy Clay Loam, and Sandy Clay with No Quicklime Added after 24 Hours Anova: Single Factor Summary of TCE Levels with No Quicklime Groups Count Sum Average Variance Sand E 10 152.6 15.3 167.8 Sandy Clay Loam 10 83.8 8.4 43.7 Sandy Clay 10 180.2 18.0 359.8 ANOVA Source of Variation Sum Squares Degrees of Freedom Mean Square F P-value F crit Between Groups 493.3 2 246.7 1.295 0.290 3.354 Within Groups 5142.4 27 190.5 Total 5635.7 29 Statistically not Different Table D-2. Summary of TCE Concentration Between all Soil Tested after 24 Hours with No Quicklime Application Anova: Single Factor Summary of TCE with No Quicklime Soil Type Count Sum Average Variance Sand E 10 152.6 15.3 167.8 Sand AE 10 1278.0 127.8 1749.2 Sandy Clay Loam 10 83.8 8.4 43.7 Sandy Clay 10 180.2 18.0 359.8 Source of Variation Sum Squares Degree of Freedom Mean Squares F P-value F crit Between Groups 97815.0 3 32605.0 56.2 0.00000000000012 2.9 Within Groups 20884.8 36 580.1 Total 118699.7 39 Statistically Different

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89 Table D-3. Statistic Summary for 5% TCE Removal after 24 Hours Anova: Single Factor Summary of TCE 5%Quicklime Addition Groups Count Sum TCE mg/kg Average TCE mg/kg Variance Sand E 10 12.6 1.3 0.7 Sand AE 10 52.7 5.3 22.5 Sandy Clay Loam 10 25.0 2.5 1.6 Sandy Clay 10 87.5 8.7 357.5 Source of Variation Sum of Squares Degree of Freedom Mean Square F P-value F crit Between Groups 331.3 3 110.4 1.2 0.34 2.9 Within Groups 3441.0 36 95.6 Total 3772.4 39 Statistically not Different

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90 Table D-4. Statistical Summary between Sandy Cl ay TCE concentrations and the other Three Soil types tested after 10% Applicat ion of Quicklime after 24 Hours Anova: Single Factor Summary of TCE Concentrations Groups Count Sum Average Variance Final TCE values (SCL, Sand AE, Sand E) 30 105.3 3.5 16.5 Sandy Clay 10 97.3 9.7 70.5 ANOVA Source of Variation Sum Square Degrees of Freedom Mean Square F P-value F crit Between Groups 290.1 1 290.1 9.9 0.0032 4.1 Within Groups 1112.4 38 29.3 Total 1402.5 39 Statistically Different Table D-5. Summary of TCE Concentration Between all Soil Tested after 24 Hours with 10% Quicklime Application Anova: Single Factor Summary of TCE Concentrations Groups Count Sum Average Variance Sand E 10 59.8 6.0 23.9 Sand AE 10 18.2 1.8 3.4 Sandy Clay Loam 10 27.4 2.7 15.2 Sandy Clay 10 97.3 9.7 70.5 ANOVA Source of Variation Sum Square Degrees of freedom Mean Square F P-value F crit Between Groups 385.5 3 128.5 4.5 0.0084 2.9 Within Groups 1017.0 36 28.2 Total 1402.5 39 Statistically Different

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91 LIST OF REFERENCES Cabbar, H.C, Bostance, A. 2001. Moisture Eff ect on the Transport of Organic Vapors in Sand. J. Hazard. Mater., B82: 313-322. Dean, Gordon. Ex-Situ Treatment of Dens e Non-Aqueous Phase Liquids Using Calcium Oxide. Contaminated Soils, Sediments and Water Eds. Edward J. Calabrese, Paul T. Kostecki and James Dragun. Springer: USA, 2005. Feenstra, Stanely. 1992. Geochemical Evaluati on of Polychlorinated Biphenyls in Groundwater Ground Water Contamination and Analysis at Hazardous. in the book; Geochemical Evaluation of Polychlorinated Biphenyls in Gr oundwater. Eds. Lesage S and Jackson, R. Published by CRC Press. 479-506. FDOT (Florida Department of Transportati on) 2002. Source Area Remediation Report FDOT Fairbanks Disposal Pit September 27, 2002. Guenzi, W.D., and Beard, W. E.197 4. Pesticides in Soil and Water Soil Science Society of America, Madison WI, USA. Khan, F.I, Husian, T., Hejazi. 2004. An Over view and Analysis of Site Remediation Technologies. J. Environ Mgt., 71: 95-122. Ko, Jeahac, Impacts of Quick lime Application on Chlorinated Ethylenes in Soil. Ph.D dissertation, University of Florida, Gainesville, FL, USA, 2007. Ma, H., Wu, K.Y, Ton, C.H., 2002 Setting Informati on Priorities for Remediation Decisions at a Contaminated-Groundwater Site. J. Chemosphere, 46: 75-81. McCoy, B.J., Rolston, D.E 1992. Convective Tran sport of Gases in Moist Porus: Effect of Absorption, Adsorption, and Diffusion in So il Aggregates. J. Environ. Sci. Technol., 26: 2466-2476. Nobre, M.M., Nobre R.C.M., 2004. Soil Vapor Extr action of Chlorinated Solvents at an Industrial Site in Brazi. J. Hazard Mater., 110: 119-127. Tekrony, M.C., Ahlert, A.C, 2001. Adsorption of Chlorinated Hydrocarbon Vapors Onto Soil in the Presence of Water. J Hazard Mater., B84: 135-146. Schifano, V., MacLeod, C., Hadlow, N., Dudene y, R., 2006. Evaluation of Quicklime Mixing for the Remediation of Petroleum Contamin ated Soils. J. Hazard Mater., 141: 395-409. TRB (Transportation Research Board) 1987. Lime Stabilization-Reaction, Properties, Design, and Construction Washington, D.C., USA. USEPA, Test Methods for Evaluating Solid Wa ste, Physical/Chemical Methods, SW 846 online, http://www.epa.gov/epaoswer/hazwaste/test/main.htm 2006.

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92 BIOGRAPHICAL SKETCH Aaron Alan Jordan was born in 1975, to Barbara Jean Jordan and James Collier Jordan, in Jacksonville, Florida. He graduated from the University of Florida in 2003, with a bachelors degree in the Department of Forest Resources and Conservation. He began graduate studies in the Department of Environmental Engin eering Sciences at the University of Florida in spring 2005, studying solid and hazardous waste with the guidance of Dr. Timothy Townsend, a long-time mentor.