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Mineral solubilization from municipal solid waste combustion residues

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Title:
Mineral solubilization from municipal solid waste combustion residues implications for landfill leachate collection systems
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Rhea, Lisa R
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University of South Florida
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Subjects / Keywords:
Waste-to-Energy
ash
batch tests
clogging
deposition
precipitates
Dissertations, Academic -- Environmental Engineering -- Masters -- USF   ( lcsh )
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government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )

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Summary:
ABSTRACT: Leachate collection systems consist of a series of pipes installed beneath the waste at the base of a landfill. The liquid drains toward a central location where it is pumped and then treated, discharged, or recirculated. In some landfills, solid precipitates form in the collection system resulting in clogging and malfunctions of the drainage system. The formation of the precipitates is linked to the chemical and biological stability of the leachate generated within the landfill. To control the formation of precipitates and prevent clogging of leachate collection systems, it is important to understand factors that influence leachate characteristics. Ashes from municipal solid waste (MSW) combustion are either placed in monofills or combined with traditional solid waste, and sludges and biosolids from wastewater and drinking water treatment plants when landfilled.The ashes, depending on the type of combustion process, contain high concentrations of metals and non-biodegradable materials. As the waste degrades, oxygen in the landfill is consumed and the leachate becomes anaerobic. The reducing environment allows for greater solubility of metals. This research tested ashes from three different Waste-to-Energy (WTE) facilities to understand better the role MSW fly ash and MSW bottom ash in the chemical make-up of landfill leachate. Two different types of batch tests were used to analyze the leaching behavior. First, a contact time batch test with a range of different contact times was used to assess the rate at which different elements reach equilibrium. This was followed by a sequential extraction batch test that predicted the total amount of soluble material in the ashes.The chemical characteristics of the leachate produced by the ashes were understood and the leaching behaviors analyzed, dominant chemical factors that influence the formation of precipitates were identified. This data produced a better understanding of the roles of WTE ashes in the production of precipitates in leachate collection systems.
Thesis:
Thesis (M.S.Env.E.)--University of South Florida, 2004.
Bibliography:
Includes bibliographical references.
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by Lisa R. Rhea.
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Title from PDF of title page.
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Document formatted into pages; contains 133 pages.

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University of South Florida
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aleph - 001498178
oclc - 57717248
notis - AJU6781
usfldc doi - E14-SFE0000534
usfldc handle - e14.534
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Mineral Solubilization from Municipa l Solid Waste Combustion Residues: Implications for Landfill Leachate Collection Systems by Lisa R. Rhea A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering Department of Civil and Environmental Engineering College of Engineering University of South Florida Major Professor: Audrey D. Levine, Ph.D. John T. Wolan, Ph.D. L. Donald Duke, Ph.D. Date of Approval: November 12, 2004 Keywords: ash, batch tests, clogging, de position, precipitates, waste-to-energy Copyright 2004 Lisa R. Rhea

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Dedication I would like to dedicate th is thesis to my family. To my husband, R. Douglas Rhea, my mother, Ruth R. Robinson and my children, Jeremiah and Elijah Van Horn. Without their support, encouragement and unde rstanding, I would not have been able to complete this thesis.

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Acknowledgements I would like to start by thanking my mentor and major professor, Dr. Audrey D. Levine, for all her guidance a nd support during the past tw o years. Her interest in environmental issues and her dedication to re search is inspiring. She encouraged me to pursue my goal of earning a Master of Scie nce degree in Environmental Engineering and gave me the opportunity to accomplish this in her lab. I appreciate the help Dr. John T. Wolan a nd Dr. L. Donald Duke provided, both in class and on this thesis. Their comments a nd suggestions helped guide me though this difficult process. I am very grateful for the opportunity to work with Antonio J. Cardoso on this project. Thank you for providing the necessa ry data on the ash monofill lysimeters. Thanks to Barbara M. Dodge and Mindy L. Decker for their help with method development and leachate characterization. I would also like to thank the Solid Wa ste Authorities of the following Florida counties for providing the ash and leachat e samples needed for this research: Hillsborough, Palm Beach, and Pasco. I would like to recognize the Florida Center for Solid and Hazardous Waste, Camp, Dresser & McKee (CDM), and the So lid Waste Authority of Palm Beach County (SWA) for funding the main project, Assessmen t of Biogeochemical Deposits in Landfill Leachate Drainage Systems, of whic h my research was a small part.

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i Table of Contents List of Tables................................................................................................................. ....iii List of Figures................................................................................................................ .....v List of Abbreviations........................................................................................................vi i Abstract....................................................................................................................... .....viii Introduction................................................................................................................... ......1 Objectives..................................................................................................................... ......3 Literature Review.............................................................................................................. ..4 Regulatory Requirements........................................................................................4 Waste-To-Energy in Florida.......................................................................5 EPA RegulationsLandfill Leachate Management....................................6 Clogging of Leachate Collection Systems..............................................................9 Leaching Tests......................................................................................................11 Field and Simulator Tests.........................................................................12 Batch Test.................................................................................................14 Experimental Methodology for Batch Test Leaching Study............................................17 Experimental Design.............................................................................................19 Batch Test Optimization...........................................................................20 Batch Test Development...........................................................................20 Preliminary Contact Time Tests...................................................21 Preliminary Sequential Extraction Tests.......................................22 Contact Time Batch Tests.........................................................................23 Sequential Extraction Batch Tests............................................................25 Quality Assurance Methods......................................................................27 Leachate Characterization.....................................................................................28

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ii Time Sensitive Tests.................................................................................30 Preserved Tests.........................................................................................31 Chemical Analysis Quality Assurance......................................................32 Data Validation and Analysis...............................................................................34 Data Validation.........................................................................................34 Analysis.....................................................................................................36 Results........................................................................................................................ .......39 Comparison of Contact Time and Se quential Extraction Batch Tests..................39 pH, Alkalinity, and Conductivity..............................................................39 Major and Minor Ions...............................................................................48 Comparison of Batch Tests, Lysi meters and Field Samples.................................54 Chemical Factors Influenci ng Precipitate Formation...........................................59 Discussion..................................................................................................................... ....65 Comments on Batch Tests....................................................................................65 Comments on Clog Formation..............................................................................68 Conclusion..................................................................................................................... ...72 Engineering Implications..................................................................................................74 Additional Research..........................................................................................................76 References..................................................................................................................... ....78 Bibliography................................................................................................................... ..81 Appendices..................................................................................................................... ...84 Appendix A: Chemical Ch aracterization Tests.................................................................85 Metals: Flame AA:................................................................................................85 Anions: Capillary Ion Electrophoresis..................................................................86 Analytical Parameters...........................................................................................87 Appendix B: Procedures for Batch Tests..........................................................................88 Sequential Extractions Batch Tests.......................................................................88 Contact Time Batch Tests.....................................................................................89 Appendix C: Data.............................................................................................................90

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iii List of Tables Table 1: WTE Facilities in Florida (FDEP, 2000)..............................................................6 Table 2: Summary of Parameters for Landfill Leachate Collection System Designs.................................................................................................................7 Table 3: Comparison of Three Types of Tests Used to Characterize the Leaching Potential of Landfilled Materials........................................................................12 Table 4: Select Design Parameters for Lysimeters...........................................................13 Table 5: Overview of the Three Ma in Categories of Batch Tests....................................15 Table 6: Comparison of Select Ba tch Leaching Tests Protocols......................................16 Table 7: Comparison of Information Lear ned from Contact Time and Sequential Extraction Batch Tests........................................................................................17 Table 8: Sources of Combustion Residues and Leachates Tested....................................18 Table 9: Time Intervals Used for Initial Batch Tests........................................................22 Table 10: Fly Ash and Distilled Water at Various L/S Ratios..........................................23 Table 11: Time Intervals for Contact Time Batch Tests...................................................23 Table 12: Chemical Characterization Test s Used for Evaluation of Leachate.................29 Table 13: Summary of Time Sensitive Chemical Analysis..............................................30 Table 14: Summary of Preserved Tests............................................................................31 Table 15: Sample ANOVA Results from Microsoft Office Excel 2003......................37 Table 16: Relationship of Q, Ksp and Saturation.............................................................38 Table 17: ANOVA Table for Batch Te st Alkalinity and pH Values................................43 Table 18: ANOVA Results Between CT and SE for Alkalinity and pH Results.............43 Table 19: Two-Tail T-Test of pH for First Four SE Results and Complete CT Results..............................................................................................................44 Table 20: Summary of Percent Decrease in Alkalinity, C onductivity, and TDS During the First Six Sequential Extractions.....................................................48 Table 21: Extractions 1 6 Sodium, Pota ssium, and Chloride Results for P, FA, and BA Leachates.............................................................................................50

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iv Table 22: Extractions 1 6 Calcium, Ca rbonate and Sulfate for P, FA, and BA Leachates..........................................................................................................52 Table 23: Summary of Percent Decrea se in Calcium, Potassium, Sodium, Carbonate, Chloride, and Sulfate for H, P, FA, and BA Leachates.................52 Table 24: Calcium / Carbonate Ratios fo r H, P, PL, FA, BA, RA1, RA5, and PBL Leachates..........................................................................................................58 Table 25: Ksp Values for Calcite, Ar agonite and Gypsum (Benjamin, 2002).................60 Table 26: Comparison of Calcium and Carbonate in Two Landfill Leachates................71 Table A 1: Conditions from Analyti cal Methods for Atomic Absorption Spectrometry, 2000. PerkinElmer..................................................................86 Table A 2: Detailed List of Analytical Tests, Methods, Storage and Preservation, and Detection Limits.......................................................................................87 Table B 1: Sample Contact Time Batch Test Intervals.....................................................89 Table C 1: Hillsborough Contact Time Data Averages and Standard Deviations...........91 Table C 2: Pasco Contact Time Data, Averages and Standard Deviations......................94 Table C 3: Fly Ash Contact Time Data, Averages and Standard Deviations...................97 Table C 4: Bottom Ash Contact Time Data Averages and Standard Deviations..........100 Table C 5: Hillsborough Sequential Extr action Data, Averages and Standard Deviations.....................................................................................................103 Table C 6: Pasco Sequential Extraction Data Averages and Standard Deviations........107 Table C 7: Fly Ash Sequential Extrac tion Data, Averages and Standard Deviations.....................................................................................................111 Table C 8: Bottom Ash Sequential Extr action Data, Averages and Standard Deviations.....................................................................................................116 Table C 9: Pasco County Ash Monofill Data, Averages and Standard Deviations........121

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v List of Figures Figure 1: Diagram of the Base of an Engineered Landfill..................................................8 Figure 2: Diagram of the Interactions Occurring in Landfills and the Relationship to Batch Tests....................................................................................................19 Figure 3: Overview of Approach Us ed for Preliminary Batch Tests................................21 Figure 4: Overview of Cont act Time Batch Tests............................................................24 Figure 5: Sequential Extracti on HDPE Reaction Containers...........................................25 Figure 6: Overview of Seque ntial Extraction Tests..........................................................26 Figure 7: Comparison of pH and Alka linity for Leachates Produced Using Contact Time Batch Tests.................................................................................40 Figure 8: Sequential Extraction Alkalinity and pH Results for Hillsborough Ash...........41 Figure 9: Sequential Extraction Alkalinit y and pH Results for Pasco Ash......................41 Figure 10: Sequential Extraction Alkalin ity and pH Results for Fly Ash........................42 Figure 11: Sequential Extraction Alkalinity and pH Results for Bottom Ash..................42 Figure 12: Conductivity and TDS for Contact Time Batch Tests....................................45 Figure 13: SE Conductivity and TDS Results for Hillsborough Ash...............................45 Figure 14: SE Conductivity and TDS Results for Pasco Ash...........................................46 Figure 15: SE Conductivity and TDS Results for Fly Ash...............................................46 Figure 16: SE Conductivity and TDS Results for Bottom Ash........................................47 Figure 17: Log Scale Concentrations of Sodium, Potassium, and Chloride from............49 Figure 18: Extractions 1 6 Sodium, Po tassium, and Chloride Results for H Leachate...........................................................................................................49 Figure 19: CT Test Calcium, Carbonate a nd Sulfate Results for H, P, FA, and BA Leachates.........................................................................................................51 Figure 20: SE Test Calcium, Carbonate and Sulfate Results for H Leachate...................51 Figure 21: Contact Time Results for Zinc Concentrations...............................................53 Figure 22: Sequential Extraction Results for Aluminum..................................................54

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vi Figure 23: Comparison of Carbonate a nd pH for FA, BA, R1, R5 and PBL Leachates.........................................................................................................55 Figure 24: Comparison of Carbonate and pH for H, P, PL, R1 and R5 Leachates..........56 Figure 25: Comparison of Calcium, Carbona te, and Sulfate for H, P, PL, R1 and R5 Leachates...................................................................................................57 Figure 26: Comparison of Calcium, Car bonate, and Sulfate for FA, BA, R1, R5 and PBL Leachates..........................................................................................57 Figure 27: Molar Concentration of Calcium, Carbonate, and Sulfate in H, P, PL, R1 and R5 Leachates.......................................................................................58 Figure 28: Molar Concentrations of Calc ium, Carbonate, and Sulfate in FA, BA, R1, R5 and PBL Leachates..............................................................................59 Figure 29: CT Leachate Saturation Index for Calcite.......................................................60 Figure 30: SE Leachate Saturation Index for Calcite.......................................................61 Figure 31: SEM Micrograph of Calcium Carbonate Crystals from Bottom Ash Leachate Samples............................................................................................62 Figure 32: CT Leachate Saturation Index for Aragonite..................................................62 Figure 33: SE Leachate Saturation Index for Aragonite...................................................63 Figure 34: CT Leachate Saturation Index for Gypsum.....................................................63 Figure 35: SE Leachates Saturation Index for Gypsum....................................................64 Figure 36: SEM Micrograph of Calcium Sulf ate Crystals from Preserved Fly Ash Sample.............................................................................................................64 Figure 37: Picture of Fly Ash from Palm Beach County, Spring 2004............................66 Figure 38: Picture of Bottom Ash fr om Palm Beach County, Spring 2004.....................66 Figure 39: SEM Micrograph of Clog Mate rial Containing Calcium, Chloride, Phosphorous, and Sulfur from Palm Beach County........................................68 Figure 40: SEM Micrograph of Calcium Cl og Material from a Palm Beach Pump Station..............................................................................................................69 Figure 41: Bacterial Particles Identified in Leachate from an Ash Monofill...................70 Figure 42: Comparison of Saturation Inde x and Calcium Concentration for Batch Tests and Leachates.........................................................................................71

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vii List of Abbreviations BA Bottom Ash CE Capillary Electrophoresis CT Contact Time EC Electric Conductivity EDS Electron Dispersive Spectroscopy FA Fly Ash FAA Flame Atomic Absorption FDEP Florida Department of Environmental Protection H Hillsborough HDPE High Density Polyethylene L/S Liquid to Solid LCS Leachate Collection System MSW Municipal Solid Waste ORP Oxidation Reduction Potential P Pasco PBL Palm Beach Leachate PL Pasco Leachate SE Sequential Extraction SEM Scanning Electron Microscopy TCLP Toxicity Characteristic Leaching Procedure TDS Total Dissolved Solids USEPA United States Environmental Protection Agency VFA Volatile Fatty Acids WTE Waste-to-Energy

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viii Mineral Solubilization from Municipa l Solid Waste Combustion Residues: Implications for Landfill Leachate Collection Systems Lisa R. Rhea ABSTRACT Leachate collection systems consist of a seri es of pipes installed beneath the waste at the base of a landfill. The liquid drains toward a central location where it is pumped and then treated, discharged, or recirculated. In some landfills, solid precipitates form in the collection system resulting in clogging and malfunctions of the drainage system. The formation of the precipitates is linked to th e chemical and biologi cal stability of the leachate generated within the landfill. To control the formation of precipitates and prevent clogging of leachate co llection systems, it is importa nt to understand factors that influence leachate characteristics. Ashes from municipal solid waste (MSW ) combustion are either placed in monofills or combined with tr aditional solid waste, and sludges and biosolids from wastewater and drinking water treatment plan ts when landfilled. The ashes, depending on the type of combustion process, contai n high concentrations of metals and nonbiodegradable materials. As the waste degr ades, oxygen in the landfill is consumed and the leachate becomes anaerobic. The reducing en vironment allows for greater solubility of metals.

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ix This research tested ashes from three different Waste-to-Ene rgy (WTE) facilities to understand better the role MSW fly ash a nd MSW bottom ash in the chemical make-up of landfill leachate. Two different types of ba tch tests were used to analyze the leaching behavior. First, a contact time batch test with a range of different contact times was used to assess the rate at which different elemen ts reach equilibrium. This was followed by a sequential extraction batch test that predicted the total amount of sol uble material in the ashes. The chemical characteristics of the leachate produced by the ashes were understood and the leaching behaviors analy zed, dominant chemical factors that influence the formation of precipitates were identified. This data produced a better understanding of the roles of WTE ashes in the production of precip itates in leachate collection systems.

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1 Introduction In landfills, the interactions of rainwater and other sources of moisture with waste constituents produce leachate. The chemical composition of leachates is controlled by several factors including: waste characteristics; quantity of liquid th at percolates through the landfill; biological activity; and the age of the landfill. In many areas of the country, water and wastewater treatment by-products and combustion residues are co-disposed with municipal solid waste (MSW). Residuals from water treatment facilities can contain high levels of inorganic compounds such as iron, aluminum, and calcium depending on the type of treatment process. Wastewater residuals (biosolids) tend to be high in organics, nutrients, and metals. Depending on the combustion process, incinerator ashes contain high concentrations of metals and non-biodegradable materials. The heterogeneity of the wastes contributes to the complexity of chemical and biological reactions that occur in the leachate. Over the last thirty years, many factor s have contributed to changes in the composition of municipal solid waste. Changi ng societal habits, including increased use of plastics, different approaches to packagi ng, and the proliferation of electronic devices, have resulted in increased amounts of non-bi odegradable materials in landfills. In Florida, many municipalities have adopted th e use of Waste-to-Energy (WTE) facilities with the main goal of reducing the net volume and mass of wastes prior to landfilling and a secondary goal of energy production (FDE P, 2000). Combining combustion residues with MSW, residuals from wastewater and wa ter treatment plants, i ndustrial by-products, and construction and demolition wastes in landfi lls affects leachate characteristics. As wastes degrade, oxygen is consumed leadi ng to anaerobic conditions. Changes in the

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2 redox potential of the leachate influence mi crobial reactions, sol ubility, and partitioning of many constituents (Kylefors, 2003). Leachates generated in landfills are mana ged in a variety of ways dictated by regulatory requirements. Leachate collection syst ems consist of a series of pipes installed beneath the waste. The liquid drains towa rd a central location where it is treated, discharged, or recirculated. It has been reported that in some landfills, solid precipitates deposit in the collection system resulting in clogging and ma lfunctions of the drainage system. The formation of precipitates is linked to the chemical and biological stability of the leachate generated within the landfill. To control the formation of precipitates and prevent clogging of leachate co llection systems, it is importa nt to understand factors that influence leachate characteristics.

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3 Objectives The purpose of this research project is to evaluate the leaching properties of WTE combustion residues that are typically landfilled. The specific objectives are: 1. Develop batch tests to evaluate leaching characteristics of bottom ash, fly ash, and mixed ashes from WTE facilities. 2. Compare leachates generated from batch te sts of combustion residues to leachates produced in laboratory lysimeters simulating monofills, landfills operating as monofills, and landfills that co -dispose ashes with MSW. 3. Identify dominant chemical factors that influence the formation of deposits in leachate collection systems.

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4 Literature Review This section discusses the state and national regulatory requirements for the operation of WTE facilities a nd landfills. Another area covere d by the literature, and of concern in the operation of lined landfills, is the potential clogging of the leachate collection system, leading to contamination of the surrounding environment. Finally the section discusses a review of batch tests that have been developed to help determine the chemical composition and possibl e toxicity of the waste ma terials placed in landfills. Regulatory Requirements Regulations for waste management and landfill design have been established to protect public health and cont rol environmental contaminatio n. In this section, regulatory requirements for management of ash generated in waste-to-energy facilities, and landfill design and operation are summarized. The federal regulations establish minimum standards and allow the states to make the ne cessary adjustment to compensate for local variations.

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5 Waste-To-Energy in Florida The construction and design of landfills in Florida is influenced by the topography and hydrology of the state. Because Florida is very flat with a shal low water table, the base of landfills is at the land surface w ith waste deposition occurring at successive elevations. In many locations, la ndfills are the only topographi c variation in an otherwise uniform environment. To reduce the vol ume of waste requir ing landfilling, many municipalities combust MSW in Waste-to-E nergy (WTE) facilitie s. Typically, MSW combustion produces energy and results in a volume reduction up to 90% and a mass reduction up to 75% (USEPA, 2004). WTE faciliti es have become an integral part of waste management in Florida (FDEP, 2000). There are currently 13 operating WTE facilit ies in the state of Florida; most of these are located near large metropolitan areas. The active WTE facilities and general information about each facility is given in Ta ble 1. Each facility is required to meet current EPA Maximum Achievable Control Technology air quality standards (FDEP, 2000). To achieve this, many of the plants ha ve upgraded air pollution control equipment from electrostatic precipitators to combined systems that include dry scrubbers, filter fabric gas, and nitrogen oxi de controls (FDEP, 2000).

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6 Table 1: WTE Facilities in Florida (FDEP, 2000) Facility Location Technology Type Megawatts of Electricity % by mass of Waste WTE % by mass of Waste Landfilled Bay Mass Burn 12.0 44 44 Broward Mass Burn 66.5 34 40 Broward Mass Burn 64.0 34 40 Dade Refuse Derived Fuel 78.5 27 50 Hillsborough Mass Burn 29.0 25 47 Hillsborough Mass Burn 22.0 25 47 Lake Mass Burn 12.5 30 43 Lee Mass Burn 30.0 37 25 Monroe Mass Burn 4.0 25 51 Palm Beach Refuse Derived Fuel 61.3 25 40 Pasco Mass Burn 31.2 34 54 Pinellas Mass Burn 75.0 40 37 Polk Wood Waste, Tire Derived Fuel 39.6 1 62 Counties with active WTE facilities burn an average of 29%, landfill 45% and recycle 26% of the MSW. The combustion resi dues are either combined with other waste streams or placed in monofills in local la ndfills. Since 1994, when the Supreme Court ruled that ash from MSW combustion must be treated as other hazardous wastes in City of Chicago vs. Environmental Defense Fund all WTE facilities have been required to test the ash using the federal Resource Conserva tion and Recovery Act testing requirements for hazardous waste, prior to disposal in lined landfills (FDEP, 2000). EPA RegulationsLandfill Leachate Management Engineered landfills are designed to pr otect the surrounding environment from contamination by leachate generated within th e landfill. The waste characteristics, age, and extent of biological activity within a landfill influence the leachate composition

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7 (USEPA, 1993). The volume of leachate genera ted by a landfill is estimated prior to construction based on the precip itation patterns for a geograp hical region. As a landfill ages, changes in the quantity and quality of th e leachate occur due to the establishment of microbial communities and the degradation and solubilization of constituents from the waste. Regulatory requirements stipulate that all landfills receiving combustion residues must have liners and leachate collection system s to prevent the migration of leachate into groundwater systems. Design requirements specified by the USEPA are summarized in Table 2. Table 2: Summary of Parameters for Landf ill Leachate Collection System Designs Parameter Section Material and Specifications Figure 1 Composite Liner Base Soil with hydraulic conductivity less than 1 x 10-7 cm/sec; Slope > 2% A Liner Flexible membrane B Leachate Collection System Drainage Layer Placed directly over liner; material based on availability of granular material or geosynthetic net; Conductivity greater than 1 x 10 -2 cm/sec; Slope > 2% C Collection Pipes Perforated; minimum 6 inch diameter; embedded within the drainage layer; strong enough to support waste and drainage layer D Filter Layer Geotextile and/or sand; Protects drainage layer from physical clogging E Adapted from EPA publication EPA530-R-93-017 The base of the composite liner, which acts as the landfill f oundation, is a 2-foot soil layer with a hydraulic conduc tivity of less than 1 x 10-7 cm/sec (USEPA, 1993). Typically, clay is used to construct this relatively impermeable layer. A flexible membrane liner covers the clay layer, and provides an additional la yer of protection in case cracking occurs in the underlying clay due to shifts in the soil. These layers provide a barrier that prevents the leachate from qui ckly traveling through the soil and into the groundwater.

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8 If the leachate develops sufficient head, it will penetrate the composite liner. To prevent the leachate from developing sufficien t head to penetrate th e composite liner, a leachate collection system (LCS) is installed ab ove the liner. Figure 1 is a diagram of the design requirements for the base of a landfill. The design parameters require the LCS maintain a leachate head of less than 30 cm (USEPA, 1993). However, during times of peak flow it is acceptable to exceed this value for short periods. Figure 1: Diagram of the Base of an Engineered Landfill The LCS consists of a series of perforat ed pipes embedded in a drainage layer. The perforated pipes are a minimum 6-inch diameter plastic pipe and are required to support the combined weight of the drainage layer and the waste when the landfill is at capacity (USEPA, 1993). If the pipes are not able to support this weight, the LCS will fail. The drainage layer material must have conductivity equal to or greater than 1 x 10-2 cm/sec, with a slope of at least 2% so that the leachate will flow towards the collection pipes (USEPA, 1993). To prevent physical clog ging of the collection pipes, the drainage material diameter must be larger than the pe rforations in the pipe. Another measure used to prevent physical clogging is the filter layer. This layer of geotextile and sand is placed Composite Liner Perforated Leachate Collection Pipe Drainage layer C Waste 30 c m A B D E Flow of leachate Flow of leachate

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9 above the drainage blanket and prevents waste from traveling into the drainage layer and the collection pipes creating physic al blockages in the flow. Biological and chemical clogs can occur in the LCS pipes. To help control the formation of mineral precipitates and biofilms, clean-out access ports need to be included in the LCS. These ports must be placed at locations that allow cleaning equipment and chemicals to access the whole system. The suggested method for removal of mineral deposits is to flush the system with a liquid that contains biocides and cleaning agents (USEPA, 1993). The cleaning removes minera l precipitates and bi ofilm buildup in the pipes, but does not prevent the formation of future clogs. Clogging of Leachate Collection Systems Typically, the design life of landfills spans several decades, depending on the available space and the quantity of waste received (Fleming, 1999). Leachate collection systems that are below the layers of waste are prone to failure from several factors including clogging (Cooke, 2001). In some landfills, evidence of clogging can be seen within 4 years of beginning operations (Rowe, 2002). The cl ogs are caused by the formati on of biofilms and insoluble mineral deposits that fill the void spaces w ithin the drainage laye r and the perforated collection pipes (Paksy, 1998). Drainage media has been implicated in th e formation of clogs in landfill leachate collection systems (Rowe, 2000) While the initial hydraulic conductivity and porosity of different media may be similar, there are di fferences in the size of the pores and the available surface area for different types of media. For a given volume, smaller media provides a greater surface area, allowing for increased biofilm development that may

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10 influence the clogging rate (Row e, 2000). Larger media provi des for larger pores sizes that result in more uniform leachate flow, maintaining the hydraulic conductivity through the collection system and reduc ing the likelihoo d of clogging. Regardless of the medium, the flow of the leachate also affects the rate at which clogs form. Clogging has been found in both sa turated and unsaturated zones of leachate collection systems. In anaer obic environments, unsaturated regions have less clogging than saturated regions due to differences in available s ubstrate for microbial activity. During times of high flow, the increased ac tivity of the microorganisms can lead to biofilm production and the precip itation of insoluble minerals In reality, the environment in the leachate collection system of a landf ill cycles between saturated and unsaturated conditions depending on precip itation patterns. Unfortunatel y, deposition of precipitates is most pronounced in regions that experien ce changing flows, cycling between saturated and unsaturated conditions (Paksy, 1998; Rowe, 2000). The formation of insoluble minerals presents a serious problem since it reduces the hydraulic conductivity of the leachate collection system. Analysis of the clog material removed from landfills in Canada and Great Britain identified calcite, CaCO3, as the major constituent in the clog material (Manning, 1999; Rowe, 2000). Other minerals containing iron, sulfide, sulfate and carbonate were also identified in the solid. One technique used by Rowe et al (2002), to characterize the am ount of calcium carbonate in the precipitate, is based on the molecular mass ratio of Ca2+ to CO3 2-, which is equal to 0.67. If the ratio is greater than 0.67, calcium is available to precipitate with other anions. When the ratio is lower than 0.67 carbonate is available to precipitate with other cations. From this approach, it was determined that the calcium rather than the carbonate limits the formation of the calcite in leac hate collection systems (Rowe, 2000). Chemical characterization of the leacha te associated with clogging material reflects the composition of the precipitate In models of leachate chemistry, CO3 2and SO4 2are the dominant anions, regardless of th e pH, and are considered supersaturated

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11 (Manning, 1999). Typically, leachates are saturated with respect to CaCO3, FeCO3, MgCO3, and Ca5(PO4)3OH (Rowe, 2002). There are also high concentrations of sodium, potassium and chloride in leachates but due to the highly soluble nature of these ions, they are not commonly found in precipitates. Supersaturated leachates provide a rich source of ions for mineral precipitation. Leaching Tests The types of waste that are placed in a landfill contribute to the leachate characteristics. Various tests have been developed to determ ine the leaching behaviors of materials (Hage, 2003). Tests used to estab lish the leaching characteristics of wastes include field tests, simulator tests and batch te sts. A comparison of these tests is given in Table 3. The tests differ mainly in duration and the presence or ab sence of biological activity. The results from these tests can be used to help predict the long-term behavior of waste as it decomposes in a landfill.

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12 Table 3: Comparison of Three Types of Tests Used to Characterize the Leaching Potential of Landfilled Materials Category Description Advantages Disadvantages Field Monitors the characteristics of leachates produced by wastes in an established landfill. Established microbial communities; heterogeneity of waste constituents Can take several years; limited access to the reacting materials; inability to determine the contribution of the various waste constituents to the characteristics of the leachate Simulator Waste is placed in a column, commonly called a lysimeter, and allowed to react over several months. Allows for the establishment of microbial communities; mimics a landfill; controlled flow of leachant; access to the reacting materials in select locations Can take months to complete; inability to determine the contribution of the individual waste constituents to the characteristics of the leachate Batch Individual wastes and select combinations of waste are placed in nonreactive containers with leachant for a specific length of time. Completed in several weeks; allows for the identification of the contribution of the individual waste constituents to the characteristics of the leachate. Missing microbial activity; limited interaction among different types of waste Field and Simulator Tests A field test is used to monitor characteri stics of leachates produced by wastes in established landfills or in controlled test ce lls (Kylefors, 2003). In both types of field tests, wastes are exposed to natural w eathering allowing for the establishment of microbial communities and production of leachat e from natural precipitation. In a test cell, the waste can be characterized prior to landfilling, while in an established landfill this information is not readily available. In either situation, the interactions of the waste and the microorganisms are hard to monitor due to the large quantity and heterogeneity of material. This type of study can take several years to complete, and, due to the lack of access to the decomposing wastes, can leave many questions unanswered. An advantage

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13 to this type of approach is it allows for the study of all of the components of a landfill, including design and daily management. The simulator test requires less time then a field test but can still take several months to complete. The design and placement of the reactors, commonly called lysimeters, depends on the purpose of the st udy and can influence the results. In a laboratory, the results may not correlate with fi eld tests due to differences in temperature, time and water to solid contact frequenc y (van der Sloot, 1998). Lysimeter design parameters from published studies are compar ed in Table 4. Typically, wastes, or other materials, are placed in a reactor and allowe d to react for a specific time period, during which liquid is circulated through the system, gas production is monitored and leachate is produced. The gas and leachate are sampled regul arly and tested for a predetermined set of parameters. Table 4: Select Design Parameters for Lysimeters Geometry of Lysimeters Material of Lysimeters Packing Material Reference: Columns: Diameter= 50mm Length= 700mm Schedule 40PVC 6-mm diameter glass beads Rowe, R.K., VanGulck, J. and Millward, S. (2002) Boxes: 0.25m x 0.6m x 0.7m PVC clear stone used for drainage blanket, 5-10yr old waste sep. by geotextile Fleming, I.R., Rowe, R.K. and Cullimore, D.R. (1999) Boxes: 3.12 m2 x 1.06m deep Brick and concrete lined with HDPE, 100-mm gravel, waste Blight, G.E., Fourie, A.B., Shamrock, J., Mbande, C. and Morris, J.W.F. (1999) Columns: Diameter= 230mm Length= 900mm MDPE/HDPE limestone / Thames gravel, 4-5 yr old waste Paksy, A., Powrie, W., Robinson, J.P. and Peeling, L. (1998)

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14 Lysimeter tests allow for a complete characterization of wastes prior to start-up and careful control of moistu re in the system. However, the environment within the reactors allows for the establishment of microbial communities. The impact of waste characteristics on the quality of the leachate can be observed. In many ways lysimeters are black boxes, since the ability to determin e a direct relationship between individual materials and leachate characteristics is unknown. Batch Test Batch Tests, also called compliance test s, can be used to determine leaching characteristics of individual wastes. An overview of batch tests, mostly developed to regulate industrial waste dis posal, is given in Table 5. The tests fall into three main categories: shake tests, pH-stat test, and se quential extractions. The shake test allows waste to be exposed to a specific amount of leachant for a predetermined length of time. After the time interval has been completed, th e leachate is analyzed for select chemical parameters, usually designated by a regulatory agency (van der Sloot, 1998). The pH-stat tests are used to determine how a material will behave in a given environment (Hage, 2003). The leachant is monitored to ensure that the pH remains constant throughout the period of contact. Once the leachate is rem oved, it is tested for a set of chemical parameters that vary depending on the goals of the test. Sequential extractions tests are used to determine the depletion of solubilizable constituents in a material. In this test, the leachant is removed and replaced until the levels of the parameters of interest are below detection limits.

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15 Table 5: Overview of the Three Main Categories of Batch Tests Batch Test Category Description Shake Test This test allows wastes to be exposed to a specific amount of leachant for a predetermined length of time. pH-Stat Test The pH-stat tests are used to assess how materials behave under constant pH for a fixed exposure time. The pH of l eachant is monitored continuously. Sequential Extraction Test This test is used to determine the amount of solubilizable constituents in wastes. After a specific amount of time, the leach ant is replaced until the parameters of interest fall below the detection limits. The main variables among the tests are th e liquid to solid mass ratio (L/S), the leaching medium, temperature, contact time and separation techni que. A comparison of batch tests that have been used to assess waste leachability is given in Table 6. By following the procedure from a ny of the assorted tests, it is possible to determine the behavior of waste as it is e xposed to a leachant. The results can be used to help predict the long-term behavior wastes within a la ndfill in the absence of microbial activity.

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16 Table 6: Comparison of Select Batch Leaching Tests Protocols Test Liquid / Solid Ratio (mass) Leaching Medium Temp Agitation Time Contact Time Separation Technique Toxicity Characteristic Leaching Procedure USEPA Method 1311 (USEPA, 1996) 20 / 1 ratio The leaching fluid used is a function of the alkalinity of the solid phase Ambient 18 hrs 18 hrs Filtration using a 0.6m glass filter pH-Stat Test European CEN, 2000 (Hage, 2003) 9 / 1 ratio pH regulated with dilute nitric acid and dilute sodium hydroxide at pH= 4, 5.5, 7, 8, 9, 10, 11, 12 Ambient Not stated 24 hrs Filtration using a 0.45 m filter ASTM Water Leach Test D-3987-85 (Bagchi, 1990) 20 / 1 ratio Ex. 70 g solid to 1400 mL of liquid Distilled Water 18 27C 18 hrs 24 hrs Decanting or pipetting Shaking Leaching Test DIN 38414 (Kylefors, 2003) 10 / 1 ratio Distilled Water Ambient 24 hrs 24 hrs Decanting or pipetting Aqueous Extracts of Soil Samples, Methods of Soil Analysis 2nd Edition (American Society of Agronomy, 1982) 1 / 1 or 5 / 1 Distilled Water Ambient 1 hrs 1 hr Filtration using a highly retentive paper Shaking Leaching Test, European CEN, 2002 (Hage, 2003) 1st interval: 2 / 1 2nd interval: 8 / 1 Distilled Water Ambient 1st interval: 6 hrs 2nd interval: 18 hrs 1st interval: 6 hrs 2nd interval: 18 hrs Filtration using a 0.45m filter Method for Accelerated Leaching of Solidified Waste USDOE BNL 52268 (Department of Nuclear Energy, 1990) Liquid volume will be 100 times the surface area of the solid Distilled or Deionizer water, the leachant can be replenished until the solid is depleted Maximum temp. of 50C None 13 intervals 2 hrs, 5 hrs, 17 hrs, 1-11 days Decanting or pipetting

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17 Experimental Methodology for Batch Test Leaching Study Two different types of batch tests were developed to charac terize the leaching potential associated with combustion re sidues: contact time tests and sequential extraction tests. The contact time test pr ovides an estimate of the time necessary to mobilize minerals from solid wastes. This test also provides insight into the sequence of dissolution, allowing for the id entification of read ily soluble species, thus providing a static view of the interacti on between the leachant and the waste material. The sequential extraction test provides a dynamic view of the material’s behavior as it encounters fresh leachant at regular time intervals. This te st allows for simulation of the sequential changes in leaching mechanisms that occur as fresh water interacts with the waste material. A comparison of the information that can be obtained from each batch test is presented in Table 7. Table 7: Comparison of Information Learned from Contact Time and Sequential Extraction Batch Tests Batch Test Time Stability Potential Solubility Contact Time Predetermined cumulative time series Equilibrium Initial solubility Sequential Extraction Fixed leachate replacement intervals Flow equivalent extraction Total soluble material In this project, combustion residues fr om three different WTE facilities were subjected to contact time and sequential extraction tests. Test methodology was adapted from the Method for Accelerated Leaching of Solidified Waste (Department of Nuclear Energy, 1990). To assess the efficiency of using batch tests to predict leachate

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18 characteristics and the potential for clogging of leachate collection systems, batch test results were compared to leachates from laboratory lysimeters containing combustion residues and landfill leachates. The sources of the combustion residues and leachates are listed in Table 8 Table 8: Sources of Combustion Residues and Leachates Tested Source Material Code Pro cessing Method Tests Run West Palm Beach County Bottom Ash BA RDF Facility Contact Time, Sequential Extraction Fly Ash FA RDF Facility Contact Time, Sequential Extraction Leachate PBL Landfill cellCo-disposal of bottom ash, fly ash, MSW, and treatment plant residuals Analysis of inorganic constituents Clogging material from leachate collection system C Landfill cellCo-disposal of bottom ash, fly ash, MSW, and treatment plant residuals Elemental Analysis of solid phase Laboratory lysimeter RA 80% bottom ash 20% fly ash Analysis of inorganic constituents Pasco County Mixed Ash P Mass Burn Contact Time, Sequential Extraction Leachate PL Landfill cellAsh monofill Analysis of inorganic constituents Hillsborough County Mixed Ash H Mass Burn Contact Time, Sequential Extraction The WTE residues were collected in 1liter LDPE bottles or 5-gallon plastic containers and upon arrival, were stored at 4C until the batch te sts were started. The batch tests were usually started within a week of acquiring each sample. In addition to the batch tests, a preliminary characterization of the material was performed, using a scanning electron microscope coupled with en ergy dispersive spectroscopy. Due to the

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19 larger particle sizes in the bottom ash, some of the materi al was ground in an electric grinder prior to starting the batch tests. Experimental Design This project was developed to evaluate the role of combustion residues in clogging of leachate collection systems. Typi cally, ash produced at WTE facilities is disposed either in a monofill or in combinati on with other waste materials. As moisture filters through landfills, leachate is produced. Unstable leachates may lead to clogging of the collection system. In this project batch te sts were developed to simulate liquid/solid interactions that occur in landfills receiv ing combustion residues. Distilled water was used as a leachant to mimic the chemical composition of rainwater. The relationship of the batch test, lysimeter tests, and field te sts is shown in Figure 2. The experimental design for each type of batch test is presented in this se ction including test optimization, initial set-up of tests, daily operations leachate analysis, and data management. Figure 2: Diagram of the Interactions Occurring in Landfills and the Relationship to Batch Tests Landfill Waste-to-Energy Combustion residuals Rainfall; Runoff Leachate Leachin g Tests Clogs Characterization Characterization Path in Landfill Com p arisons Testing and Analysis

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20 Batch Test Optimization Preliminary batch tests were conducted to optimize the liquid to solid (L/S) mass ratios of distilled water to ash and the durat ion of the contact inte rvals An overview of the approach used during the initial tests is shown in Figure 3. The preliminary tests were designed to assess the quantity of leachate produced, the concentrations of the leached constituents, and the need for pre-treatment of the solid material. The first study focused on determining the contact time intervals necessary for diffusion to occur, while providing adequate volume to conduct leachat e characterization tests. The leachates from the preliminary batch tests were characterized and the data from these initial tests was used to develop a final protocol for the te sting of the combustion residue samples. Batch Test Development Protocols for the batch tests conducted in this project were adapted from the Method for Accelerated Leachi ng of Solidified Waste (Depar tment of Nuclear Energy, 1990). All tests were conducted using Nalgen e amber high-density polyethylene (HDPE) wide mouth bottles. The HDPE bottles are non -reactive with the le achant and leachate, and do not absorb the released ions (Depar tment of Nuclear Energy, 1990). To ensure a uniform environment, in which the temperature does not change by 1C and to simulate the higher temperatures found in landfills, the containers were placed in a 35C incubator for the reaction period.

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21 Figure 3: Overview of Approach Used for Preliminary Batch Tests Preliminary Contact Time Tests The first preliminary batch tests, de signed to determine the contact time requirements of the solids and the leachant, were conducted using an L/S ratio of 10. This ratio was selected based on the EPA Toxicity Characteristic Leaching Procedure (TCLP) protocol that states that at L/S 10, the waste can be considered 100% solid and any residual water in the material can be disreg arded in the calculation of leachant waste relationships (USEPA, 1996). Three aliquots of each of two ash samplesBA and FAwere placed in individual HDPE bottles and treated according to the scheme shown in Figure 3. Distilled water was added until an L/S ratio of 10 was reached for all six bottles based on an average density of 1 g/mL for di stilled water. The contact times ranged from 24 to 120 hours, as shown in Table 9. At th e end of the assigned time interval, the leachate was removed and tested for a limited number of parameters including, pH, Weigh sample into tared HDPE bottle Add distilled water to achieve the desired L/S ratio, using 1g/mL as the density of water Place bottles with sample and water on the orbital shaker for 20 minutes Place bottles in a 35C incubator for the selected length of time Remove sample and run required tests

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22 conductivity, alkalinity, total organic carbon, total solids, and th e dissolved metals: calcium, potassium, magnesium, sodium and al uminum. Since not all tests could be run on the first day, the samples were preserved a nd stored at 4C for future analysis. Based on the results, it was concluded each sy stem approached equilibrium by 48 hours. Therefore, shorter time intervals were needed at the initiation of the leaching reactions. Table 9: Time Intervals Used for Initial Batch Tests Type of Waste FA BA Number of bottles 3 3 Respective contact times 24 hours 48 hours 120 hours 24 hours 48 hours 120 hours Preliminary Sequential Extraction Tests The second set of trial batch tests wa s designed to assess the difference in leaching based on the L/S ratio. Using FA as th e solid and distilled water as the leachant, batch tests were set up as shown in Table 10. As before, the removed leachate was tested for a limited number of parameters. However, upon removing the leachate at the end of 48 hours, an equal amount of distilled water was used to replenish the leachant, thus maintaining a constant L/S ratio in the bottl e but increasing the total L/S ratio over time. This was continued through four cycles, allowing for observa tion of the role of the L/S ratio in the depletion of soluble materials in the waste. The L/S of 4 and 6 did not provide sufficient leachate for analysis, while the L/S of 20 was too dilute. Based on this information, the actual batch tests were design ed based on an L/S value of either 8 or 10.

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23 Table 10: Fly Ash and Distilled Water at Various L/S Ratios Bottle Number Bottle 1 Bottle 2 Bottle 3 Bottle 4 Bottle 5 L/S ratio 4 6 8 10 20 Contact Time 48 hours 48 hours 48 hours 48 hours 48 hours Number of Replenishments 4 4 4 4 4 The results from the preliminary batch test s were used to set basic parameters for the contact time and sequential extraction batch tests. The establishment of equilibrium at approximately 48 hours influenced the time interv als used in both types of batch tests. The L/S =10 was determined to be the best option since sufficient leachate was produced for analysis and the solid required no pretreatment. Contact Time Batch Tests The contact time batch test was designed to yield a static view of the interaction between the waste material a nd the leachant. From this in formation, the readily soluble materials could be identified and the length of time needed for the establishment of complete equilibrium could be determined. To insure a broad view of the interaction between ash and leachant the tests were set up for 21 days with three replicates per time interval as detailed in Table 11. Table 11: Time Intervals for Contact Time Batch Tests Contact Time Group Number 1 2 3 4 5 6 7 8 9 Contact Time Hours 2 7 72 144 216 288 360 432 504 Reaction Containers 3 3 3 3 3 3 3 3 3

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24 The initial set-up for all batch tests was identical; 125 mL amber HDPE bottles were pre-cleaned by soaking in an acid bath of 1% nitric acid fo r 24 hours. The bottles were then rinsed five times with Nanopure™ wa ter and allowed to air dry for two to three days. Once completely dried, the bottles were placed on an analytical balance, tared, and approximately 13.5 grams of ash was added to each bottle. The exact mass was recorded and sufficient distilled water was added to achieve an L/S = 10. The volume added was usually slightly more then 135 ml, which completely fills the bottle, eliminating headspace. The bottles were then treated as shown in Figure 4. At the end of each time interval, the three bottles were removed from the incubator and the leachate was removed by filtration. The leachate was divided into three volumes, one for immediate testing and the other two were preserved for chemical characterization. Figure 4: Overview of Contact Time Batch Tests Weigh sample into tared HDPE bottle; Record mass of sample Add distilled water to achieve an L/S ratio of 10, using 1g/mL as the density of water Place bottles with sample and water on the orbital shaker for 20 minutes Place bottles in a 35C incubator for the selected length of tim e as shown in Table 4 Remove sample by filtration, run time sensitive tests and preserve for future analysis

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25 Sequential Extraction Batch Tests The sequential extraction batch test wa s designed to provide a dynamic view of the interaction between solids and leachants. Th e identity of the more soluble constituents was seen in the preliminary tests; however, over time the contributions of less soluble materials to the leachate became obvious. The time interval between extractions was set at 72 hours, to allow apparent equilibrium to be reached while providing adequate time to test each sequential step. The duration of the sequential extr action tests was determined by the L/S ratio, which increased with each subsequent extraction, in most cases the process lasted 3 months. The HDPE reaction containers are shown in Figure 5 and the steps taken in the sequential extractio n batch test are shown in Figure 6 Figure 5: Sequential Extraction HDPE Reaction Containers

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26 Figure 6: Overview of Sequential Extraction Tests The subsequent removal of leachate and re plenishment with distilled water started at an L/S of 10 and continued, with full chemical analysis, until the cumulative L/S ratio reached 100. By this point, a clear picture of the leaching trends of the ash was available; however, the ash was still releasing ions into solution. From L/S = 100 through L/S =200 the leachate was removed and replenished as before but the leachate was only tested for pH, temperature and conductivity. The final ex traction at an L/S = 200 was preserved and fully analyzed. Weigh sample into tared HDPE bottle; record mass of sample Add distilled water to achieve an initial L/S =10, using 1g/mL as the density of water Place bottles with sample and water on the orbital shaker for 20 minutes Place bottles in a 35C incubator for 72 hours Pipet out leachate sample Replace removed leachate with equal volume of distilled water Run analysis and preserve leachate samples

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27 Quality Assurance Methods To reduce the possibility of contamin ation during the produc tion and removal of leachate from the batch tests, several precautions were implemented. The leaching containers were made from HDPE, a material that does not interact with the leachate or the leachant and will not absorb materials re leased by the ash (Department of Nuclear Energy, 1990). The bottles and lids were pre-cleaned by soaking in a 1% nitric acid bath for 24 hours, removed, rinsed five times with Nanopure™ water, and allowed to air dry for several days. This process reduced the li kelihood of the container contaminating the sample. After each time interval, the leachate was removed by either pipetting or filtration. 25-50 mL disposable serological pipettes were used to remove the leachate from the sequential extraction batch tests. A new tip was used for each extraction and then disposed. The contact time batch test sa mples were filtered through Whatman 6 Qualitative filter paper, which retains particle s larger than 3m, using funnels that had been cleaned with Sparkleen 1 (Fisherbra nd) and rinsed with Nanopure™ water. A set of 24 Erlenmeyer flasks were initi ally acid washed in 1% nitric acid and rinsed thoroughly with Nanopure™ water. Thes e flasks were dedicated for use in this project and isolated from the general labor atory equipment. Upon the removal of the leachate from each batch test, it was placed in one of these flasks. After the completion of the initial chemical analyses, the remaini ng leachate was transferred to Fisherbrand Disposable Sterile Centrifuge t ubes for storage and preservation.

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28 Leachate Characterization The chemical characterization of the leachat e produced by each batch test, laboratory lysimeters simulating ash monofills, landfills operating as monofills and landfills that codeposit ashes with MSW included the use of several techniques The procedures used in each test were based on Standard Methods fo r the Examination of Water and Wastewater, 20th Edition (1998). A list of the tests conducted fo r this project is shown in Table 12 and detailed protocols are given in Appendix A. For this project, characterization tests were grouped into two categories, t hose that were time sensitiv e and those that could be preserved for future analysis.

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29 Table 12: Chemical Characterization Tests Used for Evaluation of Leachate Test Standard Methods, 20th Editionnumber and description Storage and Preservation Detection Limits pH 4500-H+ B. Electrometric Method inoLab pH probe, calibrated at pH=4, 7, 10 Test immediately pH of 0-14 Conductivity 2510 B. Laboratory Method inoLab conductivity probe Test immediately 1S/cm – 2 S/cm Dissolved Metals: Calcium, Copper, Iron, Magnesium, Manganese, Potassium, Sodium, Zinc 3111 B Direct Air-Acetylene Flame Method using a PerkinElmer Flame AA Preserve by adding 5mL of concentrated nitric acid to 1 L of sample. Good for up to 6 months. Prior to use adjust to pH=4. Lower limit= 0.1 mg/L to 0.01 mg/L depending on the metal Total Hardness 2340 B. Hardness by Calculation Based on metals preservation Lower limit= 1 mg/L as CaCO3 Bromide, Chloride, Fluoride, Nitrate, Nitrite, Phosphate, Sulfate 4140 B Capillary Ion Electrophoresis with indirect UV Detection. Using Beakman Capillary Electrophoresis Refrigerate at 4C and process as soon as possible For 30s sampling time, lower = 0.1 mg/L Carbonate Calculated value from Alkalinity Titration Store at 4C and analyze within 6 hours Lower limit = 12 mg/L Alkalinity 2320 B Titration Method Store at 4C and analyze within 6 hours Lower limit =20 mg/L as CaCO3 Aluminum 3500-Al B. Eriochrome Cyanine R Method Acidify with concentrated nitric acid to pH=2, good for 6 months 0.00 mg/L to 0.250 mg/L Solids (TDS) 2540 C Total Dissolved Solids Store at 4C and begin test within 3 days Lower limit= 10 mg/L TOC 5310 C. Persulfate-UV Method using a SIEVERS 800 Portable Total Organic Carbon Analyzer If the sample can not be analyzed immediately, it needs to be acidified to pH=2 with sulfuric acid Lower limit= 0.01 mg C /L Total Nitrogen 4500-N C. Persulfate Method Acidify to pH< 2 using concentrated sulfuric acid and store at 4C for up to 28 days 0-25 mg/L Total Phosphorous 4500-P C. Vanadomolybdophosphoric Acid Colormetric Method Acidify to pH< 2 using concentrated sulfuric acid and store at 4C for up to 28 days 0-25 mg/L Silica 4500-SiO2 Molybdosilicate Method Store at 4C in a plastic bottle for up to 7 days 0-100.0 mg/L

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30 Time Sensitive Tests Due to the instability of some constituent s, it was important to complete some tests immediately after samp le collection. The sample holding times ranged from immediate analysis to seven days. The time sensitive tests and the time ranges that were considered acceptable are listed in Table 13. If the tests could not be completed within the specified amount of time, the results obt ained were considered questionable due to chemical reactions that occurred in the leachate. Table 13: Summary of Time Sensitive Chemical Analysis Time Storage Tests Test Immediately None pH, Conductivity, Oxidation-Reduction Potential, Temperature Within 6 hours 4C Alkalinity Start within 3 days 4C Total Dissolved Solids Within 7 days 4C in plastic Silica As soon as possible 4C Anions (Cl-, Br-, NO2-, SO4 2-, NO3 -, F-, PO4 3-) The four tests that needed to be comp leted immediately were done using probes, which made it possible to complete the analys is within 30 minutes of sample collection. Alkalinity titrations were conducted in trip licate for each sample, so each set of extractions required nine indivi dual titrations. Generally, this could be completed within one hour of extracting the leachate. The solids analyses were also started on the same day as the leachate was extracted; a measured volume was filtered into a pre-weighed ceramic dish and placed in the oven to evaporate off the water. The final determination of the total dissolved solids took several days to comple te due to the weighing, drying and cooling cycles required by the method. The remaining tw o time sensitive tests were completed as soon as possible, usually within seven days of sampling. The silica content was measured using wet chemistry, and the anion concen trations were determined by Capillary

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31 Electrophoresis (CE). During the lag time between extractions and tests, the leachate was stored at 4C. Preserved Tests After proper preservation, leachate samples we re stored for analysis of metals and nutrients. The pH was lowered by adding a sma ll volume of concentrated acid allowing these samples to be stored for up to six months at 4C. For metal analyses preservation, 5 mL of concentrated nitric acid was added to each liter of sample. The reason for using nitric acid in the preservation of metals was that the nitrate ions released by the acid do not form precipitates with the metal cations. Concentrated sulfuric acid was used to preserve for total nitrogen, total phosphorous and total organic carbon. One interesting side effect of this preserva tion technique was the formation of calcium sulfate precipitates upon the addition of the sulfuric acid. An overview of the tests and the appropriate preservation techniques is given in Table 14. Table 14: Summary of Preserved Tests Time Preservation Storage Temperature Tests 6 months 5 mL HNO3 to 1 L sample 4C Al, Ca, Cu, Fe, Na, K, Mg, Mn, Zn 28 days pH=2 by addition of H2SO4 4C Total Nitrogen, Total Phosphorous, Total Organic Carbon Flame Atomic Absorption (FAA) was used to determine the concentration of dissolved metals in each leachate. The samples from each individual extraction were preserved and all samples from each test were analyzed as a group. The only exception was aluminum, this concentration was dete rmined using Eriochrome Cyanine R. The SIEVERS 800 Total Organic Carbon Analyzer was used to determine the TOC. The

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32 remaining two tests, Total Nitrogen, and To tal Phosphorous were colorimetric tests, requiring digestion. Hardness, a chemical test that measures the multi-valent cations in a solution, can be determined by EDTA titration or by measur ement of dominant multi-valent cations. In the analysis of leachate, the presence of large quantities of metals interferes with the color change of the indicator, making it impossi ble to detect the endpoint of the titration. Since the dominant cations in hardness ar e calcium and magnesium, the hardness was calculated using the following fo rmula: Total Hardness (mg CaCO3/L) = 2.497 [Ca2+] + 4.118[Mg2+] (Standard Methods, 1998). The calci um and magnesium concentrations were measured using the FAA. Chemical Analysis Quality Assurance To ensure the accuracy of the chemical parameters measured during leachate characterization tests, specific quality a ssurance practices were adopted. Depending on the type of equipment involved, these tests involved re-calibrati ng, testing standards, running blanks, running replicates or spiking the sample with a known ion. On occasion, to verify the accuracy of results multiple checks were employed. The pH probe and FAA required regu lar re-calibration. The pH probe was recalibrated every three to f our days using Arcos brand buffer solutions with pH = 4, 7, 10. To eliminate any cross contaminati on, the probe was thoroughly rinsed with Nanopure™ water and dried with a Kimwipe™ between testing each sample. The FAA required calibration each time it was turned on or the lamp was changed. At least five standards were used to create a calibration cu rve, with the middle concentration used to re-slope the curve. A graph of the calibration curve was prin ted at the beginning of each run to verify the accuracy of the calibration. The concentrations of the standards used in

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33 calibrating depended on the metal tested. Calcium, sodium and potassium required high range calibration curves, while iron, magne sium and manganese were low range calibrations. Since the samples were preserved at the time of extraction, all of the leachate produced by the batch tests was anal yzed using the same calibration curve. To avoid contamination, the sampling capillary was rinsed with Nanopure™ water between each sample. Three replicates were run on each sample and to insure consistency in the readings, the FAA was re-slope d after every ten samples. The CE calibration was also based on a standard curve; however, the accuracy of the curve was verified periodically instead of recalibrating the system. This verification was accomplished by processing a solution of known concentration every two weeks and analyzing the results. At times, questions cam e up about the identity of a peak on the electropherogram, and to verify the identity of th e ion producing the peak, the sample was spiked and rerun. If the peak in questi on increased in size, then its identity was verified. If a new peak appeared, then its location helped identify the peak since they always appeared in the same order. Testing a standard soluti on was the method used to in sure the validity of the conductivity and ORP probes. Two solutions we re prepared following the procedures in Standard Methods; these were 0.01 M KCl so lutions for testing conductivity and a Light’s solution for ORP (Standard Methods, 1998). The probes were placed in the appropriate solutions every two weeks and allowed to equilibrate. The reading on the conductivity probe was usually within 2% of the expected value of 1412 S/cm, indicating the accuracy of the measurements According to the ORP probe information, the Light’s standard should read between 400 and 500 mV. When tested, the ORP probe was between 430-460 mV, which indicated it was valid in an oxidized solution. Unfortunately, most of the results from the leachate were reduced and it was impossible to verify the accuracy in a reduced environm ent since a standard fo r this range was not available.

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34 One of two approaches, running replicates or processing a standard, verified the remaining tests. For the tests verified by r unning replicates, the aver age and the standard deviation were calculated and recorded. Some of the tests were very labor intensive, so completing multiple runs was impractical; in stead a standard with the concentration comparable to the expected results was run in parallel with the sample. Data Validation and Analysis To keep all of the data organized, da ta from each WTE facility was stored electronically in a separate di rectory; within the folder was an Excel workbook for each batch test. Data from individual results were entered into the appropriate spreadsheet and the significant figures verified. Since all batch tests were run in triplic ate, the results were averaged and the standard deviation was calcu lated. Any results that deviated from the average were re-examined and if needed the test were repeated. Data Validation To validate the comprehensiveness of the an alyses of the leachates, three internal checks were performed: measured TDS to conductivity ratio, measured TDS = calculated TDS, anion-cation balance. These approaches ar e described in the Data Quality section of Standard Methods (Standard Methods, 1998). The TDS test measures the mass of dissolved solids in the leachate, while conductivity measures the ability of the leachat e to conduct an electrical current. TDS to conductivity ratios between 0.55 and 0.7 were co nsidered acceptable and were calculated

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35 by dividing the TDS (mg/L) by the conduc tivity (S/cm) (Sta ndard Methods, 1998). Values that fell outside of the acceptable range indicated that one or both of the measurements were suspect and the tests need ed to be repeated. An additional technique for examining the relationship between these tw o pieces of discrete data was to graph the TDS versus conductivity and add a trend line. The slope of the trend line was positive, indicating an increase in conduc tivity with an increase in TD S. To determine the “nature and strength” of the relationship between these two parameters the Pearson ProductMoment Correlation coefficient was calcula ted (Blair, 1999). This allowed for a definitive determination of the positive correlation and the degree to which the relationship was linear. A comparison of the measured TDS and th e calculated TDS was used to ensure that most of the dominant constituents were identified. The measured TDS was determined by evaporation of the water from an aliquot of filtered leachate while the calculated TDS was arrived at by summing the concentrations of the measured constituents. In theory, if all constituents ha d been identified, the ratio of calculated TDS to measured TDS would be 1 (Standard Me thods, 1998). The acceptable ratio range for calculated TDS to measured TDS was between 0.8 and 1, values outside of the range were considered suspect and required further analysis. The final validation step focused on the i ons in the leachate. Since solutions are electrically neutral, the positive charges have to equal the negative charges. The concentrations of the measured constituents were converted from mg/L to meq/L that allowed for a comparison of the relative char ges rather than that of the masses. The formula used, taken from Standard Methods, 20th edition, for the cation-anion balance was: % Difference = 100 cations (meq/L) – anions (meq/L) cations (meq/L) + anions (meq/L)

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36 The acceptable difference for solutions of high ionic concentration was 5 percent or less (Standard Method, 1998). Analysis Several statistical and chemical technique s were employed to ev aluate batch test results and to compare results from different tests. Statistical tec hniques were used to organize and summarize the data. The chemi cal techniques provided insight into the relationships of the different elements in the leachate and the stability of the leachate. The statistical analysis is explained firs t, followed by the chemical analysis. The average, also called the arithmetic mean, measures the central tendency and standard deviation measures the variability in the data (Blair, 1999). These calculations provided insight into the precision of the da ta. The average was calculated for each CT group (Table 11) and SE extraction set, allo wing for a comparison within the groups. The average and standard deviation were calcula ted for each parameter in the completed CT tests. The one-way ANOVA F-test allowed for the comparison of results between different batch tests. With = 0.05, the ANOVA tested the null hypothesis, Ho: 1 = 1 = 1 = 1, against the alternative hypothesis, H1: not all i are equal. The calculations were performed using Microsoft Office Excel 2003, wh ich provided the statistical analysis in the form of a table as shown in Table 15.

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37 Table 15: Sample ANOVA Results fr om Microsoft Office Excel 2003 SUMMARY Groups Count Sum Average Variance H 27 37990 1407.037 32837.04 P 27 34605 1281.667 68544.23 FA 27 16550 612.963 6475.499 BA 27 41493 1536.778 44741.1 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 13694293 3 4564764 119.6547 1.37E-33 2.691979 Within Groups 3967545 104 38149.47 Total 17661838 107 The first analysis compared the results fr om H, P, FA, and BA contact time tests. The same analysis was used on the H, P, FA, and BA sequential extraction tests. The second comparison subdivided the batch test results into two categories based on the WTE facility technology, comparing H to P and FA to BA. When comparing the CT results to the SE results, th e ANOVA test was not useful due to large changes that occurred with each subsequent extraction in the SE tests. Instead, a two-sample unequal variance t-test was used to compare the fi rst four SE results to the CT results. Parameters with high degrees of variability required the use of several additional techniques. The use of trend lines and linear regressions pr ovided information about the correlation of data. The generated equation i ndicates whether the co rrelation was positive or negative and allowed for possible predicti ons of future changes. The coefficient of determination, r2, indicated the strength of the model (Blair, 1999). In th e SE results, the clearest interpretation of the data was provi ded by the percent decrease in concentration over a set number of extractions. Several techniques were used to analyze chemical data. First the concentrations were converted to mol/L by dividing the ma ss concentrations by the molar mass of the measured element. Using balanced chemical reactions and chemical formulas, a quick comparison of the molar ratios was possible. However, in concentrated solutions, the molar concentrations are insufficient in determ ining the behavior of the ions. The charges

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38 and concentrations of the ions in soluti on can influence the io nic interactions and therefore it is important to include activity corrections. First the ionic strength of the leachat e was calculated and used to calculate activity coefficients for the individual ions. Th e formula used to calculate ionic strength was I = ci z2 (Benjamin, 2002). The activity coeffici ents were calculated using the Davies equation, log DAVIES = -Az2[( I0.5/1I0.5)-0.2 I ], which is applicable for solutions with 0.1< I <0.5 (Benjamin, 2002). The Davies equa tion provides activity coefficients based on the ionic charge. Once the molar conc entrations were corrected for activity, the potential for precipitate formation wa s analyzed using saturation indices. A saturation index is the ratio of the react ion quotient, Q, to the solubility product, Ksp. The reaction quotient is the product of the molar concentr ations of the ions in the mineral, adjusted for activity. The Ksp value is an equilibrium constant and changes depending on the temperature of the system. The Ksp value was adjusted from 25C to 35C using the Arrhenius equation (Benjamin, 2002). The relationships between Q, Ksp and the saturation index ar e presented in Table 16. Table 16: Relationship of Q, Ksp and Saturation Q, Ksp Relationship Saturation Index value Level of Saturation Q < Ksp < 1 Unsaturated Q = Ksp = 1 Saturated, equilibrium Q > Ksp > 1 Supersaturated

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39 Results The results from the batch tests, lysimete r studies, and field samples are presented in this section. A comparison of selected resu lts from the contact time (CT) tests and the sequential extraction (SE) tests is provided a nd compared to characteristics of leachates from laboratory lysimeters and field samples. Batch test results are used to identify the dominant chemical factors influenc ing the formation of precipitates. Comparison of Contact Time and Sequential Extraction Batch Tests In this section results obtained from th e CT and SE tests are compared. The ash samples used in the batch tests were obtai ned from three different WTE facilities: Hillsborough (H), Pasco (P) and Palm Beach (FA and BA). pH, Alkalinity, and Conductivity Leachates from all ash samples had relatively high levels of pH regardless of source or leachate extraction method. The pH values for the leachate produced using the CT test ranged from pH = 11.3 to 12.0.while the SE resu lts ranged from pH = 10.5 to 12.0. Alkalinity is a measure of the bufferi ng capacity of a solution, and the alkalinity

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40 results differ depending on the t ype of batch test used to produce the leachate and the source of the ash. The alkalinity results were more variable than the pH results with CT test standard deviations rangi ng from 60 to 250 mg/L as CaCO3. During the first six extractions SE alkalinity values decreased by 18% to 83% (Table 20). The alkalinity and pH results for the CT tests are presented in Fi gure 7, and the SE test results are presented in Figures 8 – 11. 0 200 400 600 800 1000 1200 1400 1600 1800 2000 HPFABAAlkalinity (mg CaCO 3 / L)0 2 4 6 8 10 12 14pH Alk pH Figure 7: Comparison of pH and Alkalinity for Leachates Produced Using Contact Time Batch Tests In the SE tests, after enc ountering a mass of water equa l to 100 times the initial mass of ash, the pH values had standard devi ations of less than 0.4, and trend lines added to the pH values on Figures 8 11 having slopes of less than 0.1. An ANOVA analysis comparing the pH to the L/S ratios showed the slopes of the li nes did not deviate significantly from zero. Thus, even though there was a reduction in alkalinity, the buffering capacity of the leachate was still adeq uate to resist a change in pH. The final alkalinity values were similar to those of typical groundwater ra nging from 60 to 110 mg CaCO3 /L.

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41 y = 9.3556x2 222.02x + 1448 R2 = 0.9865 0 200 400 600 800 1000 1200 1400 1600 1800 1019283543526068768593102 L/S RatioAlkalinity (mg CaCO 3 /L)0 2 4 6 8 10 12 14pH Alkalinity pH H Figure 8: Sequential Extraction Alkalinity and pH Results for Hillsborough Ash y = 15.442x2 284.91x + 1374.6 R2 = 0.9752 0 200 400 600 800 1000 1200 1400 1600 1800 101927344148576574819099 L/S RatioAlkalinity (mg CaCO 3 /L)0 2 4 6 8 10 12 14pH Alkalinity pH P Figure 9: Sequential Extraction Alkalinity and pH Results for Pasco Ash

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42 y = -85.267x + 1539.7 R2 = 0.8516 0 200 400 600 800 1000 1200 1400 1600 1800 10172432384652596673808694101 L/S RatioAlkalinity (mg CaCO 3 /L)0 2 4 6 8 10 12 14pH Alkalinity pH FA Figure 10: Sequential Extraction Alkalinity and pH Results for Fly Ash y = 3.9444x2 98.573x + 743.57 R2 = 0.9407 0 200 400 600 800 1000 1200 1400 1600 1800 101826334048556270778594102 L/S RatioAlkalinity (mg CaCO 3 /L)0 2 4 6 8 10 12 14pH Alkalinity pH BA Figure 11: Sequential Extraction Alkalinity and pH Results for Bottom Ash A one-way ANOVA, with = 0.05, tested the null hypothesis, Ho: 1 = 1 = 1 = 1, against the alternative hypothesis, H1: not all i are equal. The results showed F > Fcritical when comparing all four sample s for alkalinity and pH, causing Ho to be rejected. However, grouping the samples according to WTE technology used at the facility changed the F statistic. ANOVAs of H and P leachates show ed no significant difference in pH, with F < Fcritical. Ho was rejected for the H and P alkalinity CT results but the SE

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43 results failed to reject Ho. An ANOVA of the CT results for FA and BA pH results showed no significant difference. The ot her ANOVAs used to analyze FA and BA showed large differences between the alkalin ities and pHs of these two samples, causing a rejection of Ho. A summary of the ANOVA results for al kalinity and pH is presented in Table 17. Table 17: ANOVA Table for Batch Test Alkalinity and pH Values Sample Type of Batch Test df F (alkalinity) Fcritical F (pH) Fcritical H, P, FA, and BA CT 107 119.67 2.69 18.97 2.69 H and P CT 53 4.19 4.03 2.15 4.03 FA and BA CT 53 449.91 4.03 0.45 4.03 H, P, FA, and BA SE 55 10.67 2.82 10.94 2.78 H and P SE 27 1.04 4.30 0.22 4.23 FA and BA SE 27 34.74 4.30 5.50 4.23 A one-way ANOVA was used to compare th e alkalinity and pH from the CT and SE leachates. There was a significant differe nce between the two batch tests. When the samples were subdivided as before, there we re significant differences between H, P and FA, while BA had an F < F critical. A summary of this analysis is presen ted in Table 18. Table 18: ANOVA Results Between CT and SE for Alkalinity and pH Results Sample Type of Batch Test df F (alkalinity) Fcritical F (pH) Fcritical H, P, FA, and BA CT and SE 95 42.53 2.12 13.14 2.10 H CT and SE 23 39.41 4.30 29.20 4.23 P CT and SE 23 32.67 4.30 33.73 4.23 FA CT and SE 23 43.64 4.26 11.57 4.23 BA CT and SE 23 24.81 4.26 1.99 4.23

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44 Because an ANOVA tests requires equal numbers of samples, a two-sample unequal variance t-test compared the first four SE results to the CT result. This analysis showed no significant differences in pH duri ng the first four extr actions. A summary of the t-test results is presented in Table 19. An obvious decrease in al kalinity with each subsequent extraction precluded the use of this comparison. Table 19: Two-Tail T-Test of pH for First Four SE Results and Complete CT Results Samples P(T<=t) two-tail t Critical H: CT and SE 0.009 2.262 P: CT and SE 0.157 3.182 FA: CT and SE 0.489 4.303 BA: CT and SE 0.002 2.776 Conductivity is a measure of a solution’s ability to conduct an electrical current and an indirect measure of the dissolved ions in a solution. TDS values directly relate to conductivity. Generally, the TDS/EC rati o for a solution is between 0.55 and 0.7 (Standard Methods, 1998). Given this relationship, the TDS re sults are expected to mirror the conductivity results. The conductivity a nd TDS results for the CT batch tests are presented Figure 12. The SE results for these two parameters are presented in Figures 13 – 16.

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45 0 5 10 15 20 25 30 35 HPFABAConductivity (mS/cm) 0 5000 10000 15000 20000TDS (mg/L) Cond TDS Figure 12: Conductivity and TDS for Contact Time Batch Tests 0 5 10 15 20 25 30 35 1019283543526068768593102 L/S RatioConductivity (mS/cm)0 5000 10000 15000 20000TDS (mg/L) Conductivity TDS H Figure 13: SE Conductivity and TD S Results for Hillsborough Ash

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46 0 5 10 15 20 25 30 35 101927344148576574819099 L/S RatioConductivity (mS/cm0 5000 10000 15000 20000TDS (mg/L) Conductivity TDS P Figure 14: SE Conductivity and TDS Results for Pasco Ash 0 5 10 15 20 25 30 35 10172432384652596673808694101 L/S RatioConductivity (mS/cm)0 5000 10000 15000 20000TDS (mg/L) Conductivity TDS FA Figure 15: SE Conductivity and TDS Results for Fly Ash

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47 0 5 10 15 20 25 30 35 101826334048556270778594102 L/S RatioConductivity (mS/cm0 5000 10000 15000 20000TDS (mg/L) Conductivity TDS BA Figure 16: SE Conductivity and TDS Results for Bottom Ash The CT batch test for H, P and BA had lower conductivity and TDS results than FA (Figure 12). The H and P ashes were quenched at the WTE facility prior to landfilling. This initial rinse removed some of the readily soluble minerals, reduced the ability of the ash to release ions and in turn lowered the conductivity. The BA had the lowest conductivity due to the insoluble nature of th e minerals found in the ash. During the SE test, for all samples, the greatest decrease in conductivity and TDS occurred during the first three extractions. Suggesting that th e readily soluble ions were washed out of the ash quickly, leaving be hind less soluble constituents. Most of the samples had a decrease greater than 85% from the initial conductivity, and 93 % from the initial TDS values after si x extractions. The bottom ash was the exception, dropping 76% and 78% respectively. A possible explanation is due to the lower con centration of soluble ions in the original bottom ash sample. The percent decrease for each sample after six extractions is presented in Table 20.

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48 Table 20: Summary of Percent Decrease in Alkalin ity, Conductivity, and TDS During the First Six Sequential Extractions H % Decrease P % Decrease FA % Decrease BA % Decrease Alkalinity 67 83 18 63 Conductivity 86 92 85 77 TDS 93 94 93 78 It should be noted that conductivity measur ements were not relia ble during part of the study making the data questionable. This co uld be considered a minor deviation given that the TDS results mirror the conductivity results. Major and Minor Ions In general, the results for the other tested parameters follow the same patterns as seen above; the CT tests estab lished equilibrium while the SE tests showed a reduction in concentration during the first six extractions. The dominant ions in the batch tests leachates were calcium, potassium, sodi um, carbonate, chloride and sulfate. The sodium, potassium and chloride ions are readily soluble and not usually found in LCS clog materials. However, an abundance of these ions does influence the ionic strength of the leachate, changing the activities of the precipi tate-forming ions. The concentrations of these three ions from CT tests are presented in Figure 17.

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49 1 10 100 1000 10000 HPF AB AConcentration (mg/L) Sodium Potassium Chloride Figure 17: Log Scale Concentrations of So dium, Potassium, and Chloride from CT Batch Tests 0 500 1000 1500 2000 2500 0102030405060 L/S RatioConcentration (mg/L) Sodium Potassium Chloride HSE Figure 18: Extractions 1 6 Sodium, Potassium, and Chloride Results for H Leachate The SE test concentrations for sodium, potassium, and chloride are presented in Figure 18 for H leachate over an L/S ratio of 10-60. These same trends were observed in all the ash samples and by the second extraction; the impact of these ions on the ionic strength of the leachate was no longer significan t. The concentrations of these ions for the first six extractions of P, FA, and BA leach ate are presented in Table 21 and the percent decreases are presented in Table 23.

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50 Table 21: Extractions 1 6 Sodium, Potassium, and Chloride Results for P, FA, and BA Leachates Sample Ion L/S 10 Conc. (mg/L) L/S 20 Conc. (mg/L) L/S 30 Conc. (mg/L) L/S 40 Conc. (mg/L) L/S 50 Conc. (mg/L) L/S 60 Conc. (mg/L) P Na+ 256 41 12 7.6 5.5 3.7 K+ 150 28 7 4.0 3.1 1.5 Cl1460 203 60 41.9 23.3 7.6 FA Na+ 1834 553 159 58.7 35.6 20.7 K+ 1164 301 68 28.1 20.2 11.6 Cl7652 3051 666 207.2 144.9 49.6 BA Na+ 61 12 6 2.9 2.9 3.1 K+ 51 15 6 2.6 1.9 1.2 Cl35 17 10 13.4 5.5 3.4 Calcium, carbonate and sulfate were the dominant ions found in the precipitates that clog LCS. The H, P, and FA ash samp les had high concentrations of calcium, ranging from 1476 mg/L to 4273 mg/L. These c oncentrations were at least double those of carbonate or sulfate. The BA sample had the lowest concentra tions, and the calcium concentration was lower than the carbonate concentrati on. These relationships are presented in Figure 19.

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51 0 1000 2000 3000 4000 5000 HPFABAConcentration (mg/L) Calcium Sulfate Carbonate Figure 19: CT Test Calcium, Carbonate and Sulfate Results for H, P, FA, and BA Leachates With the exception of BA sulfate concentrations, the SE batch test for calcium, carbonate and sulfate followed the same pattern. The concentrations decreased with each subsequent extraction. The initial six extractio ns of the Hillsborough ash are presented in Figure 20, and a summary of the P, FA and BA results are presented in Table 22. The percentage decrease of calcium, potassium, sodium, carbonate, chloride, and sulfate ions are presented in Table 23. Since the calcium, carbonate, and sulfate we re less soluble, the percent decrease was less than that of potassium, sodium and chloride. 0 300 600 900 1200 1500 1800 0102030405060 L/S RatioConcentration (mg/L) Calcium Carbonate Sulfate Figure 20: SE Test Calcium, Carbonat e and Sulfate Results for H Leachate

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52 Table 22: Extractions 1 6 Calcium, Carbonate and Sulfate for P, FA, and BA Leachates Sample Ion L/S 10 Conc. (mg/L) L/S 20 Conc. (mg/L) L/S 30 Conc. (mg/L) L/S 40 Conc. (mg/L) L/S 50 Conc. (mg/L) L/S 60 Conc. (mg/L) P Ca+2 1167 505 283 188 123 71 CO3 -2 700 544 352 244 168 128 SO4 -2 320 167 114 68 46 36 FA Ca+2 5637 2179 892 562 539 545 CO3 -2 782 806 740 628 934 640 SO4 -2 512 210 30 16 8 7 BA Ca+2 411 308 267 210 151 97 CO3 -2 382 294 350 276 218 140 SO4 -2 16 25 34 28 30 26 Table 23: Summary of Percent Decrease in Calciu m, Potassium, Sodium, Carbonate, Chloride, and Sulfate for H, P, FA, and BA Leachates Ion H % Decrease P % Decrease FA % Decrease BA % Decrease Calcium 89 94 90 76 Potassium 99 99 99 98 Sodium 99 99 99 95 Carbonate 67 82 18 63 Chloride 99 99 99 90 Sulfate 93 89 98 N/A* *BA did not show a decrease in sulfate concentration. For the other tested parameters, concentr ations were either near or below the methods detection limits. In general, thes e constituents followed the same patterns presented above, with two exceptions: CT zinc and SE aluminum. The CT zinc concentrations for H, P, and FA, even though extremely low, were highest in the first time interval of two hours and decreased as pr esented in Figure 21. This behavior implies that the zinc originally b onded to a more soluble anion and quickly dissolved. Once in

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53 solution, the zinc precipitated out of the leachat e. The other minor cations in the CT test did not exhibit any discernable patterns. 0 0.5 1 1.5 2 2.5 3 0100200300400500 Time (hours) Zinc (mg/L) H P FA BA Figure 21: Contact Time Results for Zinc Concentrations The aluminum ions in the SE tests did not exhibit the same behavior pattern as the other ions. Over time, the concentrations of aluminum in the leachates increased as presented in Figure 22. One explanation for th is behavior was that the aluminum, which had a low solubility, was bonded to an anion that washed out duri ng the extractions and the solubility equilibrium shifted to en able dissolution. Another possibility was the samples had pieces of aluminum metal that may have been oxidized to Al+3 as the leachate changed with each subsequent extr action. The pieces of aluminum metal were visible in the bottom ash samples.

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54 0 5 10 15 20 25 020406080100 L/S RatioAluminum (mg/L) H P FA BA Figure 22: Sequential Extraction Results for Aluminum As shown, the CT and SE batch tests pr esent different information about the leaching characteristics of the samples. The CT test provided information about the readily soluble minerals present in the ash a nd the time needed to establish equilibrium. Whereas, the SE test provided a more dynami c view of the leachi ng behavior, providing insight into the changes in leaching pattern s as the waste encountered fresh leachant. Comparison of Batch Tests, Lysimeters and Field Samples In this section, CT batch leachates are compared to leachates from lysimeter and landfills. The reason for using the CT resu lts in the comparison with the lysimeter monofill results (R1 and R5), provided by Cardoso (2004), is that leachate was recirculated through the lysimeter and the system had an L/S < 10. The landfill leachate was a grab sample generated by ashes of different ages and L/S ratios. The FA and BA results are compared to lysimeter leac hates (R1 and R5) and Palm Beach landfill leachates (PBL). The landfill receiving the FA and BA ashes co-deposits the ash with MSW and water and wastewater treatment sl udges. The H and P ashes are compared to

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55 R1, R5 and Pasco landfill leachate (PL). The Pasco landfill deposits the P ash received from the neighboring WTE facility in a monofill. The major elements found in LCS clog ma terial are calcium, carbon, and sulfur. The pH and concentration of ions influences the rate of precipitate formation. Because of this, the following section focuses on thes e select parameters: pH, calcium, carbonate, and sulfate. Carbonate levels for the landfill leachates were estimated from alkalinity measurements using a conversion factor of 0.60.Unfortunately, this approach overlooks the impact of volatile fatty acids (VFA) on the measured alkalinity. Carbonate is a weak diprotic acid that acts as a buffer in natural systems. The disassociation reactions and pKa’ s for the carbonate system at 25C are as follows (Kotz, 1991): H2CO3 (aq) H+ (aq) + HCO3 (aq) pKa1 = 6.38 HCO3 (aq) H+ (aq) + CO3 -2 (aq) pKa2 = 10.32 The species of carbonate present in leach ate depend on the pH of the leachate. A comparison of the carbonate concentrations and pH values of the leachates is presented in Figures 23 and 24. 0 400 800 1200 1600 2000 FABAR1R5PBLCarbonate (mg/L ) 0 2 4 6 8 10 12 14pH Carbonate pH Figure 23: Comparison of Carbonate and pH for FA, BA, R1, R5 and PBL Leachates

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56 0 400 800 1200 1600 2000 HPPLR1R5Carbonate (mg/L ) 0 2 4 6 8 10 12 14pH Carbonate pH Figure 24: Comparison of Carbonate and pH for H, P, PL, R1 and R5 Leachates The leachate produced in the laboratory had a high pH indicating that the majority of the carbonate ions were present as carbonate. The landfill leach ates had lower pH values, so the dominant species for the carbonate ions was most likely bicarbonate. The PBL leachate appears unusual in this compar ison, the low pH and high carbonate values seem contradictory. Since the landfill that ge nerated this leachate co-deposits ash with other waste materials, a high VFA concen tration probably caused the discrepancy. The calcium, carbonate, and sulfate ion concentrations for the laboratory and landfill leachates are presented in Figures 25 and 26. The concentration of calcium was higher than 1000 mg/L in all samples except BA which average 133 mg/L.

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57 1 10 100 1000 10000 HPPLR1R5Concentration (mg/L) Calcium Carbonate Sulfate Figure 25: Comparison of Calc ium, Carbonate, and Sulfate for H, P, PL, R1 and R5 Leachates 1 10 100 1000 10000 FABAR1R5PBLConcentration (mg/L) Calcium Carbonate Sulfate Figure 26: Comparison of Calcium, Ca rbonate, and Sulfate for FA, BA, R1, R5 and PBL Leachates A direct comparison of mass concentrations is deceptive since different elements have different molecular weights. Another approach, suggested by Rowe, et al. (2000), compares the ratio of calcium ions to carbona te ions. If the ratio is greater than 0.67, calcium is in excess and available to precipita te with other ions. Ta ble 24 presents the Ca+2/CO3 -2 mass ratios for each of the solutions.

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58 Table 24: Calcium / Carbonate Ratios for H, P, PL, FA, BA, RA1, RA5, and PBL Leachates H P PL FA BA R1 R5 PBL Ca+2 (mg/L) 2093 1476 5384 4273 133 2182 2071 5429 CO3 -2 (mg/L) 844 769 84 922 368 1127 1131 1008 Ratio 2.48 1.92 64 4.63 0.36 1.94 1.83 5.39 With the exception of the BA leachate, the leachate samples had excess calcium. Calcium precipitates easily w ith several ions, including car bonate, sulfate and hydroxide. Another way of presenting this information involves a comparison of molar concentrations. The ions in calcite (CaCO3) and gypsum (CaSO4) precipitates have oneto-one molar relationships. The molar concen trations of calcium, carbonate and sulfate are presented in Figures 27 and 28. 0 30 60 90 120 150 180 HPPLR1R5Concentration (mmol/L) Calcium Carbonate Sulfate Figure 27: Molar Concentration of Calciu m, Carbonate, and Sulfate in H, P, PL, R1 and R5 Leachates

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59 0 30 60 90 120 150 180 FABAR1R5PBLConcentration (mmol/L) Calcium Carbonate Sulfate Figure 28: Molar Concentrations of Calcium, Carbonate, and Sulfate in FA, BA, R1, R5 and PBL Leachates A one-way ANOVA showed significant differe nces between the concentrations of calcium, carbonate, and sulfate in the laborat ory and landfill leachates. However, the laboratory tests correctly identify the iden tities of the dominant ions and the relative proportions. The differences in the concentra tions may have been due to the microbial activity in the landfill, which was not present in the batch tests and different L/S ratios. Chemical Factors Influencing Precipitate Formation The formation of a precipitate is not only dependent on the molar ratio of the ions in the leachate, but on th e solubility product, Ksp. The Ksp value is the product of the molar concentrations, adjusted for temperature and ionic activity. In dilute systems, the activity of ions are often ignored but the leachate produced in the laboratory and in landfills precludes this omission. The fo llowing reactions describe three common precipitates found in LCS clog ma terial and the corresponding Ksp values in Table 25 (Benjamin, 2002).

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60 Calcite: Ca+2 (aq) + CO3 -2 (aq) CaCO3 (s) Aragonite: Ca+2 (aq) + CO3 -2 (aq) CaCO3 (s) Gypsum: Ca+2 (aq) + SO4 -2 (aq) CaSO4 (s) Table 25: Ksp Values for Calcite, Ar agonite and Gypsum (Benjamin, 2002) Mineral Ksp at 25C Ksp at 35C Calcite, CaCO3 (s) 10-848 10-866 Aragonite, CaCO3 (s) 10-836 10-843 Gypsum, CaSO4 (s) 10-485 10-161 If the reaction quotient (Q) is compared to the Ksp the relative degree of saturation can be assessed. The saturation indices for calcite are presented in Figures 29 and 30. 1.0E-03 1.0E-01 1.0E+01 1.0E+03 0100200300400500 Time (hours)Saturation Index (Q/Ksp) H P FA BA Saturation Figure 29: CT Leachate Saturation Index for Calcite

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61 1.0E-03 1.0E-01 1.0E+01 1.0E+03 020406080100 L/S RatioSaturation Index (Q/Ksp) H P FA BA Saturation Figure 30: SE Leachate Saturation Index for Calcite The H, P and BA leachates were all satura ted with respect to calcite, regardless of the extraction technique. The FA leachate was unsaturated for the CT test and the initial extraction of the SE test, after which it b ecame saturated. The high ionic strength of the FA leachate caused the activity of the calcium and carbonate ions to be considerably lower than the molar concentrations. Subse quent extractions flushed the more soluble ions out of the system decreasing the ioni c strength and creating a supersaturated solution. Aragonite, another calcium carbonate mineral, followed the same trend. The saturation indices for aragon ite are presented in Figures 32 and 33. A scanning electron micrograph of calcium carbonate formed in the unpreserved BA batch leachate is shown in Figure 31.

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62 Figure 31:SEM Micrograph of Calcium Carbonate Crystals from Bottom Ash Leachate Samples 1.0E-03 1.0E-01 1.0E+01 1.0E+03 0100200300400500 Time (hours)Saturation Index (Q/Ksp) H P FA BA Saturation Figure 32: CT Leachate Saturation Index for Aragonite

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63 1.0E-03 1.0E-01 1.0E+01 1.0E+03 020406080100 L/S RatioSaturation Index (Q/Ksp) H P FA BA Saturation Figure 33: SE Leachate Saturation Index for Aragonite The gypsum was unsaturated for the CT and SE test leachates and results are presented in Figures 34 and 35. Since the calc ium concentrations were high for all the leachates, the sulfate concentrations caus ed the small gypsum reaction quotient. The addition of sulfuric acid for sample preserva tion demonstrated this imbalance. A scanning electron micrograph showing the calcium sulf ate crystals formed upon the addition of sulfuric acid is shown in Figure 36. 1.0E-10 1.0E-07 1.0E-04 1.0E-01 1.0E+02 1.0E+05 0100200300400500 Time (hours)Saturation Index (Q/Ksp) H P FA BA Saturation Figure 34: CT Leachate Saturation Index for Gypsum

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64 1.0E-10 1.0E-07 1.0E-04 1.0E-01 1.0E+02 1.0E+05 020406080100 L/S RatioSaturation Index (Q/Ksp) H P FA BA Saturation Figure 35: SE Leachates Saturation Index for Gypsum Figure 36: SEM Micrograph of Calcium Sulfate Crystals from Preserved Fly Ash Sample All of the leachates examined during this study had high concentrations of calcium ions, one of the main cations in LCS clog material. The sulfur and carbon constituents limited the formation of precipita tes in ash leachates. The supersaturated ash leachates form a delicate system that can be easily disrupted by other waste materials and microbial activity.

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65 Discussion Two different types of batch tests were applied to assess the leaching potential of WTE combustion residues. In this section the strengths and weaknesses of these tests are discussed and the relevance of the information provided by the batch tests is analyzed. The ability to predict the potential fo r precipitate formation is presented. Comments on Batch Tests Batch tests were used to analyze ash samp les from three different WTE facilities. Two of the samples, fly ash and bottom ash, were provided by the same WTE facility. The fly ash, pictured in Figure 37, was homoge nous in appearance and contained fine particles. These small particles had a larger surface area, exposing mo re minerals to the leachant and increasing the solubility. The botto m ash contains a wide variety of particle sizes and is pictured in Figure 38. Some of th e materials in the botto m ash were identified as glass, tile, or metal. The ashes from Hillsborough and Pasco counties, which were mixtures of fly and bottom ash, physically resembled the bottom ash but the leaching characteristics reflected the combined nature of the source of the ash.

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66 Figure 37: Picture of Fly Ash from Palm Beach County, Spring 2004 Figure 38: Picture of Bottom Ash from Palm Beach County, Spring 2004 The batch tests developed fo r this research fell into two categories: contact time and sequential extraction. The contact time test provided a static view of the leachate produced by the ash, since the leachant remained in contact with the same material long enough to establish equilibrium. The readily so luble materials leached out of the ash and

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67 become part of the leachate. The sequential extraction test provided a dynamic view of the leaching properties of ash as fresh leachant encountered the material. Each test proved to be useful for understanding the leaching char acteristics of the mate rial being analyzed, and its potential beha vior in a landfill. The CT test provided consistent informa tion about the readily soluble material in the ash. The results proved to be reliable and reproducible, allowing for a complete analysis of the initial leaching capacity of th e ash. The time interval variations provided insight into the stability of the leachate as it remained in contact with the ash. However, the moisture that enters a landfill does not stay in one place; instead, it flows down through the layers of waste. Modifying the CT test by shortening the initial time intervals from hours to minutes would model the c ontact time of water flowing through waste materials. The first extraction from the SE batch test produced results similar to the CT test results. The difference between the two te sts became apparent as the number of extractions increased. The concentrations of the ions in soluti on dropped substantially during the first four extractions, and then a ppeared to level off. Unfortunately, each subsequent extraction increased the possibility of error. The accidental removal of ash during extraction could have changed the dynami cs of the system. By modifying the SE test, this source of error coul d be reduced. Since the majority of the soluble ions washed out of the ash during the first four extractions, the total num ber of extractions could be reduced. If larger L/S ratios are neede d, the initial ratio could be increased. Batch tests provide a clear picture of the chemical leaching properties of the waste material. This allows for the determination of potential interactions that favor the production of clogs. Unfortunately, the ba tch tests do not examine the role of microbiological activity on the leachate compos ition, neglecting an important part of landfill activity.

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68 Comments on Clog Formation In the analysis of traditional MSW landfill leachates, the calcium ion has been reported to limit the formation of pr ecipitates (Manning, 1999; Rowe, 2000). The microbiological activity consumes the biodegr adable materials, thereby increasing the carbonates and making the leachate supersaturated with carbonate and sulfate. According to Rowe et al. (2000), over 50% of the clog mate rial is calcite. In the precipitate, calcium is the dominant cation and carbonate a nd sulfate are the dominant anions. The analysis of the LCS clog material ag reed with the literature. The dominant elements in the Palm Beach clog material were calcium, carbon and sulfur. Other elements, such as iron, copper, magnesium, manganese and phosphorous were present, but in much lower amounts. SEM micrographs of clog material from Palm Beach County are shown in Figure 39 and Figure 40. SEM an alysis indicated the elemental composition of the clog material mirrored the chemical composition of the leachate from the batch tests, lysimeters and field samples. Figure 39: SEM Micrograph of Clog Material Containing Calcium, Chloride, Phosphorous, and Sulfur from Palm Beach County

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69 Figure 40: SEM Micrograph of Calcium Clog Material from a Palm Beach Pump Station The combustion process at WTE facilities consumes the biodegradable materials, reducing the organic carbon in the residuals de posited in the landfill. The total organic carbon in the ash leachates ranged from 1.5mg /L to 61.1 mg/L as carbon, much lower than leachates from other waste streams that range from 500 to 5000 mg/L as carbon (Levine, 1989). The increased calcium concentr ation and the high pH are due in part to the addition of lime used to prevent the formation of acid rain pre-cursers during combustion. Once in the landfill, the calcium in the ash becomes soluble as water percolates through the waste. The low organic carbon concentr ation in the ash provides a limited substrate for microbiological activit y. The presence of nanobacteria in ash monofill leachate can be seen in Figure 41. In ash monofills, as demonstrated by the batch tests, lysimeter studies and monofill leachate analysis, the calcium ions were present in abundance, and car bon and sulfur ions limit the formation of precipitates.

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70 Figure 41: Bacterial Particles Identified in Leachate from an Ash Monofill In landfills that co-depos it ash with MSW, the leachate equilibrium is different and appears to favor the formation of precip itates. The ash introduces a source of calcium ions, while the biological act ivity in the MSW increases the formation of carbonate. A comparison of the calcium and carbonate conc entrations in the Palm Beach and Pasco leachates is presented in Table 26. Both le achates had very high concentrations of calciumabove 5000 mg/L. However, there is a tremendous difference in the carbonate values. The Palm Beach landfill combines the ash with other waste streams that are high in carbon, providing a sour ce of carbonate. The Ca+2 / CO3 -2 ratio of the Palm Beach leachate was 5.38, indicating an excess calcium ion concentration. The Pasco landfill is a monofill, therefore the amount of carbon availa ble for biological activity is limited and the formation of carbonate is suppressed. The Ca+2 / CO3 -2 ratio for Pasco was considerably higher (64) than the Palm Beach ratio, indicating a large amount of calcium but a limited amount of carbonate, limiting the formation of calcite.

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71 Table 26: Comparison of Calcium and Carbonate in Two Landfill Leachates Leachate Source Calcium (mg/L) Carbonate (mg/L) Ca+2 / CO3 -2 ratio Palm Beach 5429 1008 5.39 Pasco 5384 84 64 The concentrations of most of the ions were higher in the landfill leachate than in the batch tests, suggesting the L/S ratio in the landfill was lower than the one used in the laboratory. A lower L/S ratio w ould make the leachate more concentrated. Even with this discrepancy, the batch tests correctly predic ted the high calcium ion concentrations found in the ash leachates and the supersaturated na ture of the leachate as shown in Figure 42. The identities of the dominant ions were es tablished, and the potential for precipitate formation confirmed. 1 10 100 1000 10000 100000 1000000 10000000 HPPLFABA PBLSaturation Inde x 1 10 100 1000Calcium (mmol/L) Saturation Index Calcium Figure 42: Comparison of Saturation Index and Calcium Concentration for Batch Tests and Leachates

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72 Conclusions Ash from three different WTE facilities two mass burn and one refuse derived fuel, were characterized using batch test s adapted from the Method for Accelerated Leaching of Solidified Waste (Department of Nuclear Energy, 1990). The goal of the characterization tests was to provide a means for predicting the contri butions of different waste streams to potential clog formation in landfill leachate collection systems. The major conclusions from this project are: 1. The contact time (CT) and sequential extr action (SE) tests developed for this project were useful for assessing the de gree of leaching that may occur from exposure of combustion residues to landfill environments. 2. The CT test provided insight into the do minant solubilizable components of waste materials and the chemical stability of leachates generated by combustion residues. 3. The SE test provided a means to quantif y the leaching behavior of combustion residues resulting from sequential exposure to rainwater as it percolates through a landfill. The ash leachates from batch and lysimeter tests contained high concentrations of calcium, potassium, s odium, carbonate, chloride, and sulfate. The sodium, potassium, and chloride ions were highly soluble and did not directly contribute to the formation of precipitates. These ions in creased the ionic strength of the leachate, thereby reducing the ac tivity of the less soluble ions in the leachate. The relationships between calci um and carbonate were used to compute saturation indices for calciu m carbonate precipitation.

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73 4. When compared with leachates from labor atory lysimeters and landfills, the batch tests correctly predicted the identities of the dominant ions and the supersaturated nature of the leachate. 5. Calcium, carbonate and sulfate ions were the major constitu ents identified in solidified materials isolated from a landfill leachate collection system. 6. If combustion residues are disposed in monofills, the potential for formation of precipitates appears to be limited by th e anions, carbonate and sulfate. 7. Leachates generated in landfills receiving MSW tend to have higher concentrations of carbonate and sulfat e than combustion residue monofills. However, in MSW leachate the low concentration of calcium limits precipitate formation and the likelihood of LCS clogging. 8. Co-disposal of combustion residues from WTE facilities with MSW in landfills provides high levels of calcium from th e combustion residues and high levels of carbonate and sulfate from biological activ ity in the MSW, thereby increasing the potential for precipitate formation a nd clogging of landfill leachate collection systems. 9. The chemical composition of solid precipitates formed in landfill leachate collection systems reflects supersaturati on of leachates due to excess calcium, carbonate, and/or sulfate. Incidental changes in redox conditions in leachate collection systems may help to initia te the formation of precipitates.

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74 Engineering Implications Landfills are designed to prevent contam ination of the surrounding environment. The covering and lining of landfills and leachate collection systems are integral components of landfill management. As co mbustion and recycling increase, the proportion of biodegradable material disposed in landfills decreases. This research has demonstrated the need for improved understanding of the leaching behavior of waste materials. The two main options for MSW ash disposal are monofilling or co-depositing the ash with other waste material s in landfills. When the ash is monofilled, the consistent environment allo ws the leachate to develop an equilibrium, keeping the supersaturated ions in solution. The co-disposal of ash with other materials changes the dynamics of the system. As leachat e moves through different types of waste, the chemical equilibrium is disturbed and precipitates form. In addition, the reducing conditions within landfills increases the solubi lity of the ions. LCS that fluctuate between reduced and oxidized conditions have a higher chances of precipitate formation. Keeping the LCS under pressure would help mainta in a reduced environment and prevent precipitate formation. Monofills appear to be the best dispos al option for MSW combustion residues, unless the chemical and biologi cal interactions of the waste materials are taken into account. This practice would prevent two supers aturated leachates fr om interacting and producing precipitates. Ash leachate is high in calcium, while MSW’s leachate is high in carbonate; this supersaturated chemical combin ation has the potential of forming calcite. Calcite, a hard mineral, clogs the LCS, pr eventing the collection of the leachate thus increases the leachate head on the liner.

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75 The waste materials have the potential of producing highly reactive leachates. The materials used in the constructi on of the liner and LCS need to be able to withstand this reactive environment. Characte rization of the leachate produced by the expected waste materials in batch tests can be used as a gui de for the selection of the appropriate for landfill construction.

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76 Additional Research Recommendations for further research of the impacts of current combustion technologies and ash handling protocols on the leaching characteristic s of ash produced at WTE facilities. 1. Research the effects of different ai r pollution control devices on leaching properties of fly ash. The addition of chem icals to control the emissions of acid rain pre-cursers may affect the leachab le mineral content. Determining if a relationship exists could provide a basis for developing improved ash management practices. 2. Examine the impact of quenching the ash in water prior to landfilling on the initial soluble mineral content of combustion residue s. This initial rinse appears to play a role in the leaching behavior of ash as demonstrated by this thesis. To determine if the initial rinse has a significant impact on the leaching behavior of the ash, pre and post quenching ash samples should be an alyzed in parallel using batch and lysimeter tests. 3. Examine the changes in leaching charact eristics as WTE ashe s are exposed to periods of wetting and drying. It is possi ble that the changing moisture and redox conditions influence the leaching propertie s of the ash. Using the SE batch test approach, the ash could be dried at ambient conditi ons for a couple of days between leachate replenishments. Running this test in parallel with traditional SE tests would answer this question.

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77 4. Determine the role of increasing temperat ures on the leaching behavior of WTE combustion residues. By running identic al CT batch tests at different temperatures, a relationship between the temperature and the leachate characteristics can be established. 5. Perform a statistical analysis of the waste disposal practices an d the incidences of clog formation in leachate collections systems. This could be achieved by conducting a large scale survey of Class I landfills in the United States and comparing the disposal practices, co -disposal of ash and MSW versus monofilling, and the formation of precipitates in LCS.

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78 References American Society of Agronomy, Inc. (1982). Methods of Soil Analysis, Part 2Chemical and Microbiological Properties, 2nd Edition (pp. 167-178). Madison, WI. APHA, AWWA, WEF (1998). Standard Methods for the Examination of Water and Wastewater, 20th Edition Baltimore, MD. Bagchi, A. (1990). Design, Construction and Monito ring of Sanitary Landfill New York: John Wiley and Sons. Benjamin, Mark A. (2002). Water Chemistry New York: McGraw Hill. Blair, R.C., and Taylor, R.A. (1999). Biostatistics for the Health Sciences Manuscript submitted for publication. Blight, G.E., Fourie, A.B., Shamrock, J., Mbande, C. and Morris, J.W.F. (1999). The Effect of Waste Composition on Leachat e and Gas Quality: A Study in South Africa. Waste Management & Research 17, 124-140. Cardoso, Antonio (2004). Biologically Induced Clogging of Leachate Collection System Unpublished master’s thesis, Universi ty of South Florida, Tampa, FL. Cooke, A.J., Rowe, R.K., Rittman, B.E., VanGluck, J. and Millward, S. (2001). Biofilm Growth and Mineral Precipitation in Synthetic Leachate Columns. Journal of Geotechnical and Geoenvironmental Engineering 127 (No. 10), 849-856. Fleming, I.R., Rowe, R.K. and Cullimore, D. R. (1999). Field Observations of Clogging in a Landfill Leachate Collection System. Canadian Geotechnical Journal 36 (No. 4), 685-707.

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79 Florida Department of Envi ronmental Protection (2000). Solid Waste Management in Florida. Bureau of Solid and Hazardous Waste, July, 2000. Tallahassee, FL. Hage, J.L.T., and Mulder, E. (2003). Prelim inary Assessment of Three New European Leaching Tests. Waste Management 24, 165-172. Kotz, John C., and Purcell, Keith F. (1991). Chemistry and Chemical Reactivity, Second Edition Orlando, FL: Holt, Rinehart and Winston. Kylefors, K., Andreas, L, and Lagerkvist, A. (2003). A Comparison of Small-Scale, Pilot-Scale and Large-Scale Tests for Pr edicting Leaching Behavior of Landfilled Wastes. Waste Management 23, 45-59. Levine, A.D. and Kroemer, L.R. (1989). A Cr itical Look at the Use of TOC and TOX as Indicator Parameters for Organic Contaminants in Landfill Leachates. Waste Management and Research 7, 337-349. Manning, K.C. and Robinson, N. (1999). Leach ate Mineral Reactions: Application for Drainage System Stability and Clogging Proceedings of the Seventh International Waste Manage ment and Landfill Symposium Cagliari, Italy, October, 99, 269-276. Paksy, A., Powrie, W., Robinson, J.P. and P eeling, L. (1998). A Laboratory Investigation of Anaerobic Microbial Clogging in Gr anular Landfill Drainage Media. Geotechnique 48 (No. 3), 389-401. Rowe, R.K., Armstrong, M.D. and Cullimore, D.R. (2000). Mass Loading and the Rate of Clogging due to Municipal Solid Waste Leachate. Canadian Geotechnical Journal 37 (No. 2), 355-370. Rowe, R.K., VanGulck, J. and Millward, S. (2002). Biologically Induced Clogging of a Granular Medium Permeated with Synthetic Leachate. Canadian Journal of Environmental Engineering and Science 1, 135-156. U.S. Department of Nuclear Energy (1990). Method for Accelerated Leaching of Solidified Waste BNL 52268. Upton, New York. U.S. Environmental Protection Agency (1993). Solid Waste Disposal Facility Criteria EPA530-R-93-017. Washington D.C.

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80 U.S. Environmental Protection Agency ( 1996). Toxicity Characteristic Leaching Procedure (TCLP) Method 1311. SW 846 Test Methods for Evaluating Solid Wastes, Physical/Chemical Methods, 3rd Edition United States Department of Environmental Protection. Washington, D.C. U.S. Environmental Protection Agen cy (2004). Municipal Solid Waste. http://www.epa.gov/epaoswer/non-hw/muncpl/disposal.htm Accessed September, 2004. van der Sloot, H.A. (1998). Quick Techniques for Evaluating the Leaching Properties of Waste Materials: Their Relation to D ecisions on Utilization and Disposal. Trends in Analytical Chemistry 17, (No. 5), 298-310.

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81 Bibliography Abbas, Z., Moghaddam, A.P., Steenari, B.M. (2003). Release of Salts from Municipal Solid Waste Combustion Residues. Waste Management 23, 291-305. Bennett, P.J., Longstaffe, F.J. and Rowe, R.K. (2000). The Stability of Dolomite in Landfill Leachate Collection Systems. Canadian Geotechnical Journal 37 (No. 2), 371-378. Berenyi, Eileen B. (1996). The Status of Municipal Waste Combustion in the United States. Journal of Hazardous Materials 47, 1-17. Brereton, Clive (1996). Municipal Solid WasteIncineration, Air Pollution Control and Ash Management. Resources, Conservation and Recycling 16, 227-264. Bruder-Hubscher, V., Lagarde, F., Leroy, M.J.F., Coughanowr, C., and Enguehard, F. (2002). Application of a Sequential Extrac tion Procedure to Study the Release of Elements from Municipal Solid Waste Incineration Bottom Ash. Analytica Chimica Acta 451, 285-295. Chimenos, J.M., Fernandez, A.I., Miralles, L ., Segarra, M., Espiell, F. (in press). Shortterm natural weathering of MSWI bottom ash as a function of particle size. Waste Management. Choi, S.K., Lee, S., Song, Y.K., Moon, H.S. ( 2002). Leaching characteri stics of selected Korean fly ashes and its implications for the groundwater composition near the ash disposal mound. Fuel, 81, 1083-1090. Cooke, A.J. and Rowe, R.K.(1999). Extension of Porosity and Surface Area Models for Uniform Porous Media. Journal of Environmental Engineering 125 (No. 2),126145.

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82 Cooke, A.J., Rowe, R.K., Rittman, B.E. and Fleming, I.R. (1999). Modelling Biochemically Driven Mineral Pr ecipitation in Anerobic Biofilm. Water, Science and Technology 39 (No. 7), 57-64. Dijkstra, J.J., van der Sloot, H.A., and Coma ns, R.N.J. (2002). Pro cess Identification and Model Development of Contaminan t Transport in MSWI Bottom Ash. Waste Management 22, 531-541. Kim, A.G., Kazonich, G., and Dahlberg, M. ( 2003). Relative Solubility of Cations in Class F Fly Ash. Environmental Science and Technology 37, 4507-4511. Kim, I., Batchelor, B. (2001). Empirical Partitioning Leach Model for Solidified/Stabilized Wastes. Journal of Environmental Engineering 127 (No. 3) 188-195. Lapa, N., Barbosa, R., Morais, B., Mendes, B ., Mehu, J. and Santos Olivera, J.F. (2002). Ecotoxicological Assessment of L eachates from MSWI Bottom Ashes. Waste Management 22, 583-593. Lopes, M.H., Abelha, P., Lapa, N., Oliveira J.S., Cabrita, I., and Gulyurtlu, I. (2003). The Behavior of Ashes and Heavy Meta ls During the Co-combustion of Sewage Sludges in a Fluidised Bed. Waste Management 23, 859-870. Mostbauer, P. (2003). Criteria selection for landfills: Do we need a limitation on inorganic total content? Waste Management 23, 547-554. Peeling, L., Paksy, A., Robinson, J.P. and Powr ie, W. (1999). Removal of Volatile Acids from Synthetic Landfill Leachate by Anaer obic Biofilms on Drainage Aggregates: A Laboratory Study. Waste Management & Research 17, 141-149. Pfeffer, J. (1992). Solid Waste Management Engineering Englewood Cliffs, New Jersey: Prentice-Hall Inc., A Simon & Schuster Company. Rowe, R.K., Armstrong, M.D. and Cullimore, D. R. (2000). Particle Size and Clogging of Granular Media Permeated with Leachate. Journal of Geotechnical and Geoenvironmental Engineering 126 (No. 9), 775-786. Rowe, R.K. and Booker, J.R. (1998). Modell ing Impacts Due to Multiple Landfill Cells and Clogging of Leachate Collection Systems. Canadian Geotechnical Journal 35 (No. 1), 1-14.

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83 Rowe, R.K. and Fleming, J.R. (1998). “Estimating the Time for Clogging of Leachate Collection Systems”, Proceedings of the 3rd International Congress on Environmental Geotechnics Lisbon, September, Vol. 1, pp.23-28. Rowe, R.K., Fleming, I.R., Rittman, B.R., Longstaffe, F.J., Cullimore, D.R., Moissac, R., Bennett, P., Cooke, A.J., Armstrong, M.D., and VanGulck, J. (2000). Multidisciplinary Study of Cl ogging of Leachate Drains. 6th Environmental Engineering Specialty Conference of the CSCE London, Ontario, June. Song, G., Kim, H., Seo, Y., and Kim, S. (2004) Characteristics of Ashes from Different Locations at the MSW Incinerator Equi pped with Various Air Pollution Control Devices. Waste Management 24, 99-106. Thipse, S.S., and Dreizin, E.L. (2002). Metal Partitioning in Products of Incineration of Municipal Solid Waste. Chemosphere 46, 837-849.

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84 Appendices

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85 Appendix A: Chemical Ch aracterization Tests Metals: Flame AA Calcium, Copper, Iron, Magnesium, Ma nganese, Potassium, Sodium, Zinc Source: Standard Methods for the Exami nation of Water and Wastewater 20th edition, 3111 B Direct Air-Acetylene Flame Method Equipment: PerkinElmer AAnalyst 100, Atomic Absorption Spectrometer Time Frame: 6 months with preservation, store at 4C. Preservation of Sample: Preserve by adding 5mL of concentrated nitric acid to 1 L of sample and the sample can be stored for up to 6 months (EPA Method 3005). Preparation of Reference Standards: Make up at least three standards. The first should be below the expected concentra tion, the second should be near the expected concentration and the final standard should be above the expected concentration. The middle standard will be used to re-slope. Prepare by adding th e appropriate amount of reference standard to reagent grade water. Preparation of Sample: If th ere are large amounts of partic ulate matter the sample needs to be filtered. If not, ther e is no preparation required.

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86 Appendix A (continued) Table A 1: Conditions from Analytical Methods for Atomic Absorption Spectrometry, 2000. PerkinElmer Metal Wavelength (nm) Slit (nm) Relative Noise Characteristic Concentrations (mg/L) Characteristic concentration checks (mg/L) Linear Range (mg/L) Ca 422.7 0.7 1.00 0.092 4.00 5.0 Cu 324.8 0.7 1.00 0.077 4.00 5.0 Fe 248.3 0.2 1.00 0.110 6.00 6.0 Mg 285.2 0.7 1.00 0.008 0.30 0.5 K 766.5 0.7 1.00 0.043 2.00 2.0 769.9 0.7 1.40 0.083 4.00 20.0 Na 589.0 0.2 1.00 0.012 0.50 1.0 330.2 0.7 0.63 1.700 80.00 --Zn 213.9 0.7 1.00 0.018 1.00 1.0 Recommended Flame: Air-acetylene, oxidizing (lean, blue) Anions: Capillary Ion Electrophoresis Chloride, Bromide, Nitrate, Nitrit e, Sulfate, Fluoride, o-Phosphate Source: Standard Methods for the Exami nation of Water and Wastewater 20th edition, 4140 B: Capillary Ion Electrophoresi s with Indirect UV Detection Equipment: Beckman P/ACE 5000 Series Capillary Electroph oresis System eCap Capillary Tubing in cartridge : 375 m O.D., 75 m I.D., 50 cm L Preparation: The samples need to be filtered if it contains a high concentration of suspended solids. Once completed the sample may need to be diluted.

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87 Appendix A (continued) Analytical Parameters Table A 2: Detailed List of Analytical Tests, Methods, Storage and Preservation, and Detection Limits Test Standard Method, 20th Editionnumber, description Storage and Preservation Detection Limits pH 4500-H+ B. Electrometric Method inoLab pH probe, calibrated at pH=4, 7, 10 Test immediately pH of 0-14 Conductivity 2510 B. Laboratory Method inoLab conductivity probe Test immediately 1 S/cm – 2 S/cm Dissolved Metals: Calcium, Copper, Iron, Magnesium, Manganese, Potassium, Sodium, Zinc 3111 B Direct Air-Acetylene Flame Method using a PerkinElmer Flame AA Preserve by adding 5mL of concentrated nitric acid to 1 L of sample. Good for up to 6 months. Prior to use adjust to pH=4. Lower limit= 0.1 mg/L to 0.01 mg/L depending on metal Total Hardness 2340 B. Hardness by Calculation Based on metals preservation Lower limit= 1 mg/L Bromide, Chloride, Fluoride, Nitrate, Nitrite, Phosphate, Sulfate 4140 B Capillary Ion Electrophoresis with indirect UV Detection. Using Beakman Capillary Electrophoresis Refrigerate at 4C and process as soon as possible For 30s sampling time, lower = 0.1 mg/L Carbonate Calculated value from Alkalinity Titration Store at 4C and analyze within 6 hours Lower limit = 12 mg/L Alkalinity 2320 B Titration Method Store at 4C and analyze within 6 hours Lower limit =20 mg/L as CaCO3 Aluminum 3500-Al B. Eriochrome Cyanine R Method Acidify with concentrated nitric acid to pH=2, good for 6 months 0.00 mg/L to 0.250 mg/L Solids (TDS) 2540 C Total Solids Store at 4C and begin test within 3 days Lower limit= 10 mg/L TOC 5310 C. Persulfate-UV Method using a SIEVERS 800 Portable Total Organic Carbon Analyzer If the sample can not be analyzed immediately, it needs to be acidified to pH=2 with sulfuric acid Lower limit =0.01 mg TOC /L Total Nitrogen 4500-N C. Persulfate Method Acidify to pH< 2 using concentrated sulfuric acid and store at 4C for up to 28 days 0-25 mg/L Total Phosphorous 4500-P C. Vanadomolybdophosphoric Acid Colormetric Method Acidify to pH< 2 using concentrated sulfuric acid and store at 4C for up to 28 days 0-25 mg/L Silica 4500-SiO2 Molybdosilicate Method Store at 4C in a plastic bottle for up to 7 days 0-100.0 mg/L

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88 Appendix B: Procedures for Batch Tests Sequential Extractions Batch Tests Contact Time of 72 hours Procedure: 1. Prepare four High Density Polyethylene ( HDPE) bottles for use by washing with Sparleen 1, rinsing thoroughl y, and soaking in a 1% nitric acid bath for 24 hours. Upon removal, rinse the bottles with Nanopure™ water and allowed to air dry. 2. Place dry bottles on an analytical balance, tare, and add the solid material. Record the mass of material added. Repeat with three prepared bottles. 3. Use the weight of solid added to the bo ttle to determine the volume of distilled water needed to achieve an L/S = 10. Assume water has a density of 1g/1mL. Note: There should be almost no headspace in the container. 4. Fill one of the HDPE bottles full of distilled water as a control. 5. Tightly cap the bottles, shake vigorously for 1 minute, and placed on the orbital shaker for 20 minutes. 6. Place the well-shaken bottles in a 351C incubator for 72 hours. 7. After 72 hours, carefully removed the bottles from the incubator. Use a pipet to remove the leachate from the bottles, this must be done carefully since the solids cannot be disturbed or removed. Record the amount of leachate removed from the bottle and replenish with an equal am ount of the 351C distilled water. 8. The removed leachate needs to be promptly tested or preserved. 9. Repeat steps 6 – 9 until the total L/S ratio is reached.

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89 Appendix B (continued) Contact Time Batch Tests Procedure: 1. Prepare High Density Polyethylene (HDPE) bottles for use by washing with Sparleen 1, rinsing thoroughl y, and soaking in a 1% nitric acid bath for 24 hours. Upon removal, rinse the bottles with Nanopure™ water and allowed to air dry. 2. Place dry bottles on an analytical balance, tare, and add the solid material. Record the mass of material added. Repeat with three prepared bottles. 3. Use the weight of solid added to the bo ttle to determine the volume of distilled water needed to achieve an L/S = 10. Assume water has a density of 1g/1mL. Note: There should be almost no headspace in the container. 4. Fill one of the HDPE bottles full of distilled water as a control. 5. Tightly cap the bottles, shake vigorously for 1 minute, and placed on the orbital shaker for 20 minutes. 6. Place the well-shaken bottles in a 351C incubator for the predetermined time intervals. A sample of the time intervals is presented in Table. Table B 1: Sample Contact Time Batch Test Intervals Sample # # Bottles Contact time 1 3 2 hours 2 3 7 hours 3 3 3 day 4 3 6 days 5 3 9 days 6 3 12 days 7 3 15 days 8 3 18 days 9 3 21 days 7. After the designated contact time is comp lete, remove the bottle removed from the incubator. Filter the contents to sepa rate the leachate from the solid material. 8. The removed leachate needs to be promptly tested or preserved.

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90 Appendix C: Data Table C 1: Hillsborough Contact Time Data Averages and Standard Deviations...........91 Table C 2: Pasco Contact Time Data, Averages and Standard Deviations......................94 Table C 3: Fly Ash Contact Time Data, Averages and Standard Deviations...................97 Table C 4: Bottom Ash Contact Time Data Averages and Standard Deviations..........100 Table C 5: Hillsborough Sequential Extr action Data, Averages and Standard Deviations.....................................................................................................103 Table C 6: Pasco Sequential Extraction Data Averages and Standard Deviations........107 Table C 7: Fly Ash Sequential Extrac tion Data, Averages and Standard Deviations.....................................................................................................111 Table C 8: Bottom Ash Sequential Extr action Data, Averages and Standard Deviations.....................................................................................................116 Table C 9: Pasco County Ash Monofill Data, Averages and Standard Deviations........121

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91 Appendix C (continued) Table C 1: Hillsborough Contact Time Data, Averages and Standard Deviations Hours 2 7 72 Date of Extraction: 7/22/04 7/22/04 7/25/04 mL of H2O 135 135 135 mass of Ash (g) 13.4378 0.1380 13.5698 0.1938 13.7010 0.1993 Test H1 : Avg. Std. Dev. H2 : Avg. Std. Dev. H3 : Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1450 100 1057 12 1187 12 Aluminum (mg/L) 0.0400 0.0100 0.0900 0.0707 BDL BDL Bromide (mg/L) 46.7 6.8 40.3 8.0 31.2 3.6 Calcium (mg/L) 2174 300 1604 30 1806 166 Carbonate (mg/L) 870 60 634 7 712 7 Chloride (mg/L) 2615 200 2201 289 1856 169 Conductivity (mS/cm) 12.25 0.84 10.67 0.92 10.25 0.39 Copper (mg/L) 0.1190 0.0542 0.1173 0.0273 0.1183 0.0527 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 5430 745 4007 74 4510 413 Iron (mg/L) 0.2813 0.0685 0.2530 0.0922 0.2737 0.0299 Magnesium (mg/L) 0.1053 0.0806 0.0437 0.0051 0.0557 0.0058 Manganese (mg/L) 0.0633 0.0085 0.0527 0.0040 0.0637 0.0040 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -80 10 pH 11.87 0.12 11.64 0.06 11.90 0.06 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 200.0 20.1 172.7 36.1 156.0 16.5 Silica (mg/L as SiO2) 0.5 0.4 0.7 0.2 0.7 0.3 Sodium (mg/L) 434.0 24.6 421.3 134.5 383.3 59.5 Solids (TDS) mg/L 6800 471 5953 637 5930 477 Sulfate (mg/L) 197.8 12.8 167.5 5.9 239.4 7.9 Temperature (C) 21.43 0.40 23.47 0.15 21.67 1.91 TOC (mg/L as C) 7.62 0.72 4.77 0.22 BDL Total Nitrogen (mg/L as N) 24.5 33.2 6.0 4.2 1.7 0.6 Total Phosphorous (mg/L as PO4) 0.5 0.4 0.7 0.3 0.2 Zinc (mg/L) 2.3850 0.3196 1.8163 0.1447 0.7073 0.0657 TDS Value 6800 5953 5930 mass (dissolved) 6566.01 5250.64 5187.47 % identified 96.56 88.20 87.48 TDS/EC ratio 0.555 0.558 0.578

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92 Appendix C (continued) Table C 1: Continued Hours 144 216 288 Date of Extraction: 7/28/04 7/31/04 8/3/04 mL of H2O 135 135 135 mass of Ash (g) 13.4967 0.1918 13.5647 0.2255 13.6617 0.2153 Test H4 : Avg. Std. Dev. H5 : Avg. Std. Dev. H6 : Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1343 32 1413 60 1527 95 Aluminum (mg/L) BDL BDL 0.0867 0.0153 Bromide (mg/L) 44.7 0.4 42.5 13.5 35.1 9.8 Calcium (mg/L) 2140 128 2030 273 2592 421 Carbonate (mg/L) 806 19 848 36 916 57 Chloride (mg/L) 2276 118 2155 516 1940 295 Conductivity (mS/cm) 11.99 0.43 11.59 1.73 11.63 1.82 Copper (mg/L) 0.1057 0.0222 0.1193 0.0232 0.2597 0.2454 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 5343 323 5070 685 6473 1049 Iron (mg/L) 0.2707 0.0234 0.2560 0.0056 0.2387 0.0605 Magnesium (mg/L) 0.0440 0.0062 0.0390 0.0026 0.0450 0.0026 Manganese (mg/L) 0.0700 0.0061 0.0517 0.0061 0.0493 0.0042 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -101 3 -70 9 -65 5 pH 11.67 0.07 11.96 0.01 11.63 0.04 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 197.0 13.2 177.3 48.8 157.7 33.0 Silica (mg/L as SiO2) 0.4 0.2 0.1 0.0 1.3 0.1 Sodium (mg/L) 456.0 14.7 435.7 136.0 423.3 96.7 Solids (TDS) mg/L 7150 295 6553 1133 6430 887 Sulfate (mg/L) 322.0 42.3 295.1 108.9 333.5 19.8 Temperature (C) 21.23 0.06 20.03 0.06 22.10 1.84 TOC (mg/L as C) 6.86 0.02 Total Nitrogen (mg/L as N) 3.5 2.1 2.0 BDL 10.7 11.0 Total Phosphorous (mg/L as PO4) BDL 0.8 BDL Zinc (mg/L) 1.1427 0.1561 0.9160 0.1733 0.6960 0.0175 TDS Value 7150 6553 6430 mass (dissolved) 6246.80 5988.15 6410.54 % identified 87.37 91.38 99.70 TDS/EC ratio 0.596 0.566 0.553

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93 Appendix C (continued) Table C 1: Continued Hours 360 432 504 Date of Extraction: 8/6/04 8/9/04 8/12/04 mL of H2O 135 135 135 mass of Ash (g) 13.4506 0.0509 13.5471 0.0774 13.5336 0.0265 Test H7 : Avg. Std. Dev. H8 : Avg. Std. Dev. H9 : Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1590 52 1547 29 1550 44 Aluminum (mg/L) BDL BDL 0.0350 0.0071 Bromide (mg/L) 30.5 3.9 44.0 1.9 44.6 5.6 Calcium (mg/L) 2611 409 2085 193 1794 343 Carbonate (mg/L) 954 31 928 17 930 26 Chloride (mg/L) 2058 180 1805 215 1831 220 Conductivity (mS/cm) 12.51 0.67 12.24 0.80 10.94 0.20 Copper (mg/L) 0.2023 0.2226 0.0930 0.0035 0.2107 0.0743 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 6520 1022 5203 484 4480 854 Iron (mg/L) 0.2937 0.0420 0.2703 0.0184 0.2657 0.0258 Magnesium (mg/L) 0.0347 0.0012 0.0330 0.0017 0.0370 0.0040 Manganese (mg/L) 0.0537 0.0006 0.0560 0.0080 0.0593 0.0032 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -74 3 -79 6 -70 1 pH 11.62 0.05 11.65 0.03 11.75 0.01 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 169.3 16.6 149.7 22.1 154.3 27.1 Silica (mg/L as SiO2) 1.7 0.3 1.2 0.1 1.4 0.2 Sodium (mg/L) 416.0 78.5 331.7 64.5 331.3 82.1 Solids (TDS) mg/L 6680 497 6333 457 6123 757 Sulfate (mg/L) 323.8 44.2 263.1 26.1 252.4 63.0 Temperature (C) 23.23 0.29 24.00 0.26 21.67 0.06 TOC (mg/L as C) 5.64 0.02 7.11 1.39 Total Nitrogen (mg/L as N) 5.5 6.4 2.0 1.7 10.7 10.0 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.7047 0.0922 0.7087 0.0401 0.6433 0.1512 TDS Value 6680 6333 6123 mass (dissolved) 6571.49 5610.83 5351.65 % identified 98.38 88.59 87.40 TDS/EC ratio 0.534 0.517 0.560

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94 Appendix C (continued) Table C 2: Pasco Contact Time Data, Averages and Standard Deviations Hours 2 7 72 Date of Extraction: 16-Jul-04 16-Jul-04 19-Jul-04 mL of H2O 138.9 0.7 140.0 1.1 140.6 0.5 mass of Ash (g) 13.7576 0.0292 13.6430 0.2800 13.7414 0.0992 Test P1 : Avg. Std. Dev. P2 : Avg. Std. Dev. P3 : Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 850 218 972 276 1243 183 Aluminum (mg/L) 0.115 0.078 0.042 0.050 0.059 0.054 Bromide (mg/L) 22.0 4.1 30.9 9.0 40.1 8.3 Calcium (mg/L) 1004 142 1051 223 1509 227 Carbonate (mg/L) 510 131 583 166 746 110 Chloride (mg/L) 1232 74 1368 209 1827 319 Conductivity (mS/cm) 8.05 0.91 9.03 1.52 10.35 1.06 Copper (mg/L) 0.0403 0.0076 0.0423 0.0116 0.0540 0.0161 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 2508 354 2624 557 3768 566 Iron (mg/L) 0.1870 0.0637 0.1690 0.0696 0.2270 0.0272 Magnesium (mg/L) 0.0557 0.0187 0.0573 0.0103 0.0387 0.0284 Manganese (mg/L) 0.0530 0.0010 0.0497 0.0021 0.0537 0.0023 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -61 7 -66 26 -77 25 pH 11.71 0.07 11.79 0.11 11.74 0.07 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 109.0 2.0 124.0 20.1 157.0 19.1 Silica (mg/L as SiO2) 0.6 0.2 0.6 0.5 0.6 0.1 Sodium (mg/L) 212.3 17.2 227.3 36.4 314.0 22.3 Solids (TDS) mg/L 3937 225 4340 742 5647 480 Sulfate (mg/L) 196.0 36.3 190.0 16.6 324.0 58.4 Temperature (C) 23.60 0.44 25.80 0.72 23.53 0.29 TOC (mg/L as C) 8.420 0.057 8.085 0.035 Total Nitrogen (mg/L as N) 4.7 1.5 5.0 1.0 5.3 1.2 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 2.4187 0.9705 1.7100 0.6569 1.8343 0.4087 TDS Value 3937 4340 5647 mass (dissolved) 3294 3582 4925 % identified 84 83 87 TDS/EC ratio 0.489 0.481 0.546

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95 Appendix C (continued) Table C 2: Continued Hours 144 216 288 Date of Extraction: 22-Jul-04 25-Jul-04 28-Jul-04 mL of H2O 140.5 0.5 141.0 0.8 140.5 0.4 mass of Ash (g) 13.5964 0.3312 13.8089 0.1565 13.6477 0.2394 Test P4 : Avg. Std. Dev. P5 : Avg. Std. Dev. P6 : Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1163 12 1457 71 1363 90 Aluminum (mg/L) 0.050 BDL 0.115 0.064 Bromide (mg/L) 32.4 3.9 37.4 8.4 18.8 6.1 Calcium (mg/L) 1405 138 1866 627 1634 148 Carbonate (mg/L) 698 7 874 43 818 54 Chloride (mg/L) 1856 334 1583 489 1442 288 Conductivity (mS/cm) 9.95 0.74 12.49 2.76 10.04 0.47 Copper (mg/L) 0.2190 0.2953 0.0690 0.0212 0.0687 0.0162 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 3509 345 4660 1566 4079 371 Iron (mg/L) 0.1780 0.0277 0.2307 0.0490 0.2097 0.0199 Magnesium (mg/L) 0.0580 0.0131 0.0477 0.0055 0.0530 0.0090 Manganese (mg/L) 0.0520 0.0061 0.0567 0.0076 0.0527 0.0040 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -103 2 -78 1 pH 11.76 0.05 11.78 0.09 11.89 0.04 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 139.0 20.8 204.0 102.6 146.7 17.0 Silica (mg/L as SiO2) 0.2 0.0 0.5 0.1 0.5 0.6 Sodium (mg/L) 280.0 51.0 342.0 138.2 277.3 61.1 Solids (TDS) mg/L 5207 474 6503 1974 5553 215 Sulfate (mg/L) 577.7 206.2 374.3 23.3 266.0 80.9 Temperature (C) 24.73 0.47 25.80 0.20 22.20 0.52 TOC (mg/L as C) 8.465 2.878 Total Nitrogen (mg/L as N) 4.0 1.0 4.7 0.6 3.7 0.6 Total Phosphorous (mg/L as PO4) 0.1 0.2 0.6 0.9 BDL Zinc (mg/L) 1.2020 0.1333 1.8037 0.2729 0.8677 0.1852 TDS Value 5207 6503 5553 mass (dissolved) 4995 5289 4608 % identified 96 81 83 TDS/EC ratio 0.523 0.521 0.553

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96 Appendix C (continued) Table C 2: Continued Hours 360 432 504 Date of Extraction: 31-Jul-04 3-Aug-04 6-Aug-04 mL of H2O 141.0 0.3 141.2 0.5 140.7 1.8 mass of Ash (g) 13.6899 0.1881 13.6310 0.2777 13.6242 0.2253 Test P7 : Avg. Std. Dev. P8 : Avg. St d. Dev. P9 : Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1450 44 1480 17 1557 23 Aluminum (mg/L) BDL 0.153 0.100 BDL Bromide (mg/L) 19.2 4.0 21.5 2.6 22.7 5.4 Calcium (mg/L) 1573 67 1685 195 1562 164 Carbonate (mg/L) 870 26 888 10 934 14 Chloride (mg/L) 1462 220 1592 96 1550 73 Conductivity (mS/cm) 9.13 0.63 10.99 0.40 10.57 0.21 Copper (mg/L) 0.0817 0.0105 0.0590 0.0017 0.1033 0.0794 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 3927 167 4208 486 3900 410 Iron (mg/L) 0.2127 0.0673 0.2007 0.0471 0.1907 0.0469 Magnesium (mg/L) 0.0397 0.0035 0.0387 0.0025 0.0397 0.0064 Manganese (mg/L) 0.0557 0.0015 0.0513 0.0025 0.0520 0.0026 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -63 1 -58 2 -71 1 pH 12.03 0.03 11.71 0.04 11.74 0.02 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 123.3 20.6 143.0 11.5 137.3 7.6 Silica (mg/L as SiO2) 0.4 0.5 0.7 0.1 0.8 0.2 Sodium (mg/L) 229.0 36.5 254.3 8.7 252.0 9.6 Solids (TDS) mg/L 5133 497 5487 214 5297 95 Sulfate (mg/L) 337.7 66.6 345.0 46.9 308.0 81.5 Temperature (C) 19.73 0.21 23.73 0.21 23.80 0.17 TOC (mg/L as C) 61.450 0.495 14.360 11.370 Total Nitrogen (mg/L as N) 10.3 14.6 0.7 0.6 2.3 1.2 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 1.0727 0.5000 0.8833 0.1202 0.6393 0.0439 TDS Value 5133 5487 5297 mass (dissolved) 4626 4931 4770 % identified 90 90 90 TDS/EC ratio 0.562 0.499 0.501

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97 Appendix C (continued) Table C 3: Fly Ash Contact Time Data, Averages and Standard Deviations Hours 2 7 72 Date of Extraction: 28-Jun-04 28-Jun-04 1-Jul-04 mL of H2O 135.0 135.0 135.0 mass of Ash (g) 13.5083 0.0990 13.3782 0.0859 13.5834 0.0481 Test FA1:Avg. Std. Dev. FA2:Avg. Std. Dev. FA3:Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1953 137 1690 115 1693 110 Aluminum (mg/L) 0.133 0.049 0.120 0.078 0.113 0.064 Bromide (mg/L) 191.3 14.2 177.4 7.4 206.0 5.3 Calcium (mg/L) 3624 196 4007 172 4304 143 Carbonate (mg/L) 1172 82 1014 69 1016 66 Chloride (mg/L) 8499 599 8523 447 8370 318 Conductivity (mS/cm) 28.33 1.66 26.97 2.37 23.67 2.32 Copper (mg/L) 0.1157 0.0119 0.1127 0.0021 0.1117 0.0050 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 9050 486 10007 431 10747 359 Iron (mg/L) 0.3283 0.0232 0.3360 0.0165 0.3483 0.0601 Magnesium (mg/L) 0.0687 0.0281 0.0480 0.0108 0.0583 0.0046 Manganese (mg/L) 0.0523 0.0049 0.0463 0.0067 0.0470 0.0036 Nitrate (mg/L) BDL 7 BDL Nitrite (mg/L) BDL BDL 39 ORP (mV) -71 3 -56 25 -70 2 pH 11.66 0.05 11.53 0.06 11.60 0.02 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 988.4 51.4 829.6 301.7 1053.9 14.9 Silica (mg/L as SiO2) 0.5 0.1 1.0 0.6 0.2 0.1 Sodium (mg/L) 1377.7 80.5 1411.7 101.0 1487.3 51.5 Solids (TDS) mg/L 16830 1079 16587 644 18077 426 Sulfate (mg/L) 623.5 164.5 569.2 83.0 605.9 93.4 Temperature (C) 20.73 0.25 21.73 0.61 23.60 1.48 TOC (mg/L as C) 6.7 1.7 5.2 0.1 BDL Total Nitrogen (mg/L as N) 4.3 1.6 9.6 7.4 5.3 3.3 Total Phosphorous (mg/L as PO4) 3.2 0.5 14.8 7.5 2.5 1.6 Zinc (mg/L) 0.558 0.237 0.919 0.065 0.643 0.268 TDS Value 16830 16587 18077 mass (dissolved) 16485 16560 17052 % identified 98 100 94 TDS/EC ratio 0.594 0.615 0.764

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98 Appendix C (continued) Table C 3: Continued Hours 144 216 288 Date of Extraction: 4-Jul-04 7-Jul-04 10-Jul-04 mL of H2O 135.0 135.0 135.0 mass of Ash (g) 13.6186 0.0074 13.7732 0.1548 13.6717 0.1116 Test FA4:Avg. Std. Dev. FA5:Avg. Std. Dev. FA6:Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1561 106 1403 40 1413 12 Aluminum (mg/L) 0.117 0.032 0.053 0.029 0.275 0.332 Bromide (mg/L) 232.0 231.3 7.0 285.3 20.0 Calcium (mg/L) 4398 85 4381 30 4373 102 Carbonate (mg/L) 937 63 842 24 848 7 Chloride (mg/L) 9055 197 8910 157 8297 478 Conductivity (mS/cm) 22.23 0.32 29.60 0.17 25.27 0.32 Copper (mg/L) 0.1067 0.0038 0.1240 0.0101 0.1220 0.0104 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 10983 211 10940 75 10920 252 Iron (mg/L) 0.3393 0.0127 0.3323 0.1564 0.3707 0.0273 Magnesium (mg/L) 0.0473 0.0035 0.0530 0.0070 0.0600 0.0123 Manganese (mg/L) 0.0460 0.0040 0.0410 0.0046 0.0397 0.0057 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -9 6 -69 1 -22 5 pH 11.53 0.04 11.56 0.02 11.65 0.02 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 1072.5 10.0 1098.5 14.3 1090.7 11.2 Silica (mg/L as SiO2) 0.3 0.2 0.7 0.7 0.4 0.2 Sodium (mg/L) 1554.0 44.0 1596.3 81.8 1616.0 30.4 Solids (TDS) mg/L 17287 47 18037 255 17800 46 Sulfate (mg/L) 516.3 11.3 342.3 13.5 253.1 8.5 Temperature (C) 25.00 0.36 24.10 0.10 25.67 0.32 TOC (mg/L as C) 5.2 0.1 4.8 0.0 Total Nitrogen (mg/L as N) 0.8 0.5 1.0 0.7 1.4 0.4 Total Phosphorous (mg/L as PO4) 7.0 4.2 3.2 0.3 5.3 0.2 Zinc (mg/L) 0.512 0.419 0.933 0.025 0.827 0.005 TDS Value 17287 18037 17800 mass (dissolved) 17774 17408 16773 % identified 103 97 94 TDS/EC ratio 0.778 0.609 0.704

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99 Appendix C (continued) Table C 3: Continued Hours 360 432 504 Date of Extraction: 13-Jul-04 16-Jul-04 19-Jul-04 mL of H2O 135.0 135.0 135.0 mass of Ash (g) 13.7741 0.0574 13.6580 0.1293 13.5255 0.1077 Test FA7:Avg. Std. Dev. FA8:Avg. Std. Dev. FA9:Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 1363 45 1323 45 1430 85 Aluminum (mg/L) 0.603 0.984 0.030 BDL Bromide (mg/L) 291.3 4.2 252.0 2.0 295.3 7.6 Calcium (mg/L) 4525 129 4567 11 4283 53 Carbonate (mg/L) 818 27 794 27 858 51 Chloride (mg/L) 8565 68 7435 120 8566 277 Conductivity (mS/cm) 22.83 0.47 20.55 2.00 16.67 0.16 Copper (mg/L) 0.1160 0.0070 0.1117 0.0107 0.1020 0.0010 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 11300 321 11403 25 10693 132 Iron (mg/L) 0.4403 0.0700 0.4093 0.0119 0.4100 0.1159 Magnesium (mg/L) 0.0523 0.0154 0.0433 0.0081 0.0393 0.0029 Manganese (mg/L) 0.0423 0.0055 0.0360 0.0026 0.0363 0.0025 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -46 9 -59 1 pH 11.50 0.05 11.44 0.01 11.55 0.01 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 1137.2 15.2 982.6 56.2 1130.8 33.4 Silica (mg/L as SiO2) 0.8 0.5 0.2 0.1 0.3 0.1 Sodium (mg/L) 1853.0 470.8 2346.0 174.9 1598.7 33.6 Solids (TDS) mg/L 17460 201 17037 57 17323 189 Sulfate (mg/L) 198.7 13.3 111.5 54.7 71.3 13.3 Temperature (C) 25.07 0.61 26.97 3.26 23.57 0.29 TOC (mg/L as C) 4.9 0.1 5.1 Total Nitrogen (mg/L as N) 0.8 0.2 1.1 0.4 0.7 0.8 Total Phosphorous (mg/L as PO4) 5.4 0.5 5.0 0.3 5.2 0.2 Zinc (mg/L) 0.583 0.293 0.568 0.070 0.416 0.181 TDS Value 17460 17037 17323 mass (dissolved) 17397 16495 16810 % identified 100 97 97 TDS/EC ratio 0.765 0.829 1.039

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100 Appendix C (continued) Table C 4: Bottom Ash Contact Time Data, Averages and Standard Deviations Hours 2 7 72 Date of Extraction: 7/1/04 7/1/04 7/4/04 mL of H2O 132.0 0.0 132.0 0.0 134.7 1.5 mass of Ash (g) 13.6084 0.1589 13.5375 0.1376 13.5934 0.1294 Test BA1:Avg. Std. Dev. BA2:Avg. Std. Dev. BA3:Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 470 70 580 40 650 132 Aluminum (mg/L) 18.3 4.1 46.1 10.9 126.9 91.4 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 155 13 167 17 125 27 Carbonate (mg/L) 282 42 348 24 390 79 Chloride (mg/L) 38 10 39 3 87 15 Conductivity (mS/cm) 2.13 0.12 2.21 0.18 1.73 0.39 Copper (mg/L) 0.136 0.023 0.131 0.004 0.099 0.014 Fluoride (mg/L) 0.4 0.0 0.5 0.6 0.1 Hardness (mg CaCO3 / L) 387 35 417 40 313 65 Iron (mg/L) 0.193 0.044 0.161 0.064 0.186 0.010 Magnesium (mg/L) 0.038 0.009 0.048 0.013 0.025 0.004 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) 0.4 BDL 0.6 0.0 Nitrite (mg/L) BDL BDL BDL ORP (mV) -141 4 -187 7 -155 15 pH 11.62 0.03 11.95 0.01 11.71 0.12 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 18.9 3.3 21.0 1.9 18.5 7.4 Silica (mg/L as SiO2) 1.6 0.6 4.0 1.4 30.8 37.9 Sodium (mg/L) 42.9 10.3 49.1 7.4 43.0 8.8 Solids (TDS) mg/L 573 60 673 38 967 283 Sulfate (mg/L) 7.6 0.9 7.2 1.0 13.2 3.3 Temperature (C) 23.80 0.26 23.37 0.25 23.80 0.36 TOC (mg/L as C) 12.05 1.91 11.55 0.35 Total Nitrogen (mg/L as N) 4.4 4.3 2.0 0.6 1.0 0.4 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.062 0.014 0.070 0.004 0.059 0.011 TDS Value 573 673 967 mass (dissolved) 570 684 837 % identified 99 102 87 TDS/EC ratio 0.269 0.305 0.559

PAGE 113

101 Appendix C (continued) Table C 4: Continued Hours 144 216 288 Date of Extraction: 7/7/04 7/10/04 7/13/04 mL of H2O 134.7 0.6 135.0 0.0 135.0 0.0 mass of Ash (g) 13.6185 0.0871 13.5937 0.0244 13.5941 0.1087 Test BA4:Avg. Std. Dev. BA5:Avg. Std. Dev. BA6:Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 667 95 630 26 633 68 Aluminum (mg/L) 152.2 71.3 116.7 36.1 149.7 47.4 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 126 23 134 25 124 14 Carbonate (mg/L) 400 57 378 16 380 41 Chloride (mg/L) 84 5 36 2 104 9 Conductivity (mS/cm) 1.74 0.29 2.10 0.35 1.90 0.16 Copper (mg/L) 0.139 0.025 0.138 0.004 0.142 0.005 Fluoride (mg/L) 0.6 0.0 BDL 0.8 0.0 Hardness (mg CaCO3 / L) 313 59 333 64 310 35 Iron (mg/L) 0.240 0.046 0.239 0.028 0.137 0.029 Magnesium (mg/L) 0.031 0.002 0.024 0.005 0.022 0.002 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) 0.4 0.2 0.5 0.6 Nitrite (mg/L) BDL BDL BDL ORP (mV) -60 2 -127 28 pH 11.56 0.13 11.67 0.05 11.43 0.23 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 22.9 1.4 23.1 1.5 23.5 1.6 Silica (mg/L as SiO2) 25.3 9.0 3.2 13.0 4.4 Sodium (mg/L) 50.1 5.7 48.0 4.1 52.2 8.3 Solids (TDS) mg/L 1010 212 877 98 943 170 Sulfate (mg/L) 10.6 0.7 4.2 0.5 11.8 1.3 Temperature (C) 24.17 0.06 25.50 1.21 24.93 0.25 TOC (mg/L as C) 12.40 0.57 14.05 0.35 Total Nitrogen (mg/L as N) 1.4 0.1 1.1 0.3 1.2 0.1 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.077 0.017 0.107 0.011 0.101 0.013 TDS Value 1010 877 943 mass (dissolved) 874 751 861 % identified 87 86 91 TDS/EC ratio 0.581 0.418 0.497

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102 Appendix C (continued) Table C 4: Continued Hours 360 432 504 Date of Extraction: 7/16/04 7/19/04 7/22/04 mL of H2O 135.0 0.0 135.0 0.0 135.0 0.0 mass of Ash (g) 13.5507 0.1734 13.4526 0.0903 13.6090 0.1494 Test BA7:Avg. Std. Dev. BA8:Avg. Std. Dev. BA9:Avg. Std. Dev. Alkalinity (mg CaCO3 / L) 623 50 653 15 610 26 Aluminum (mg/L) 134.7 65.6 188.7 1.5 114.7 43.3 Bromide (mg/L) BDL 2.8 0.4 BDL Calcium (mg/L) 139 58 101 1 122 16 Carbonate (mg/L) 374 30 392 9 366 16 Chloride (mg/L) 120 3 115 10 59 12 Conductivity (mS/cm) 2.29 0.70 1.41 0.06 1.70 0.25 Copper (mg/L) 0.128 0.002 0.131 0.009 0.141 0.007 Fluoride (mg/L) 0.8 0.0 0.7 0.0 BDL Hardness (mg CaCO3 / L) 347 142 257 6 303 42 Iron (mg/L) 0.201 0.097 0.237 0.035 0.288 0.035 Magnesium (mg/L) 0.026 0.004 0.018 0.001 0.020 0.004 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -115 9 -93 11 -81 6 pH 11.45 0.21 11.40 0.08 11.48 0.06 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 26.3 1.4 24.7 4.1 22.6 5.3 Silica (mg/L as SiO2) 6.8 5.6 13.8 6.4 0.4 0.4 Sodium (mg/L) 57.6 0.9 53.1 0.6 52.3 7.8 Solids (TDS) mg/L 927 95 1003 108 870 104 Sulfate (mg/L) 16.9 4.0 17.5 1.7 9.3 1.4 Temperature (C) 30.50 0.26 22.80 0.20 23.50 0.20 TOC (mg/L as C) 16.90 14.35 3.04 Total Nitrogen (mg/L as N) 1.1 0.1 2.0 1.4 1.3 0.4 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.111 0.028 0.085 0.007 0.108 0.014 TDS Value 927 1003 870 mass (dissolved) 878 912 747 % identified 95 91 86 TDS/EC ratio 0.405 0.712 0.511

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103 Appendix C (continued) Table C 5: Hillsborough Sequential Extraction Data, Averages and Standard Deviations Mass of Ash = 13.4054 g Extraction Number 1st 2nd 3rd Date of Extraction: 25-Jul-04 28-Jul-04 31-Jul-04 mL of H2O 138.5 0.9 256.2 3.1 372.8 5.1 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 1217 93 983 35 957 40 Aluminum (mg/L) 0.000 0.000 0.080 0.066 0.460 0.679 Bromide (mg/L) 59.9 10.3 11.0 3.8 2.1 0.5 Calcium (mg/L) 1457 236 585 70 462 62 Carbonate (mg/L) 730 56 590 21 574 24 Chloride (mg/L) 2152 247 373 70 103 23 Conductivity (mS/cm) 12.00 1.21 4.85 0.42 3.73 0.28 Copper (mg/L) 0.130 0.120 0.118 0.136 0.135 0.095 Fluoride (mg/L) BDL 2.03 2.80 0.16 Hardness (mg CaCO3 / L) 3639 590 1460 174 1155 154 Iron (mg/L) 0.162 0.008 0.123 0.022 0.176 0.014 Magnesium (mg/L) 0.098 0.038 0.054 0.021 0.317 0.019 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -118 13 -119 6 -90 5 pH 11.78 0.03 11.70 0.05 11.82 0.15 Phosphate (mg/L) BDL BDL 3.75 Potassium (mg/L) 242.9 37.4 40.3 1.1 13.1 0.9 Silica (mg/L as SiO2) 0.7 0.4 1.1 0.4 6.0 3.7 Sodium (mg/L) 445.7 56.5 63.0 37.0 20.4 2.2 Solids (TDS) mg/L 6400 771 2113 110 1343 188 Sulfate (mg/L) 244.3 48.6 161.1 27.9 128.7 36.9 Temperature (C) 25.13 0.25 21.20 0.10 21.77 0.35 Total Nitrogen (mg/L as N) 11.8 4.6 6.9 3.8 3.0 2.3 Total Phosphorous (mg/L as PO4) 0.3 0.2 0.2 0.1 0.9 0.4 Zinc (mg/L) 1.676 0.161 0.458 0.037 0.553 0.062 TDS Value 6400 2113 1343 mass (dissolved) 5347 1834 1321 % identified 84 87 98 L/S Ratio 10 19 28 TDS/EC ratio 0.533 0.435 0.360

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104 Appendix C (continued) Table C 5: Continued Mass of Ash = 13.4054 g Extraction Number 4th 5th 6th Date of Extraction: 3-Aug-04 6-Aug-04 9-Aug-04 mL of H2O 467.2 8.1 580.8 8.4 696.8 8.4 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 780 139 543 87 400 61 Aluminum (mg/L) 0.140 0.044 0.517 0.436 1.460 0.316 Bromide (mg/L) 1.4 0.3 0.3 Calcium (mg/L) 338 75 197 37 162 27 Carbonate (mg/L) 468 83 326 52 240 36 Chloride (mg/L) 49 14 19 2 12 2 Conductivity (mS/cm) 3.20 0.74 2.20 0.31 1.65 0.22 Copper (mg/L) 0.122 0.075 0.066 0.091 0.065 0.050 Fluoride (mg/L) 2.72 0.13 2.62 0.04 1.15 0.03 Hardness (mg CaCO3 / L) 845 189 491 91 406 69 Iron (mg/L) 0.125 0.019 0.127 0.014 0.170 0.061 Magnesium (mg/L) 0.081 0.013 0.058 0.033 0.191 0.185 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -97 1 -82 6 -67 11 pH 11.34 0.11 11.15 0.11 11.35 0.14 Phosphate (mg/L) 3.66 0.13 3.55 0.02 1.81 0.11 Potassium (mg/L) 5.7 1.4 2.8 0.5 1.8 0.3 Silica (mg/L as SiO2) 2.6 0.3 4.0 1.6 5.0 1.3 Sodium (mg/L) 11.0 1.7 6.6 0.5 5.0 1.0 Solids (TDS) mg/L 983 189 603 87 443 67 Sulfate (mg/L) 73.7 32.9 22.0 5.1 14.9 1.2 Temperature (C) 26.27 0.31 26.37 0.12 25.87 0.78 Total Nitrogen (mg/L as N) 2.3 1.4 1.4 0.9 0.6 0.4 Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.332 0.040 0.240 0.028 0.335 0.163 TDS Value 983 603 443 mass (dissolved) 959 586 447 % identified 98 97 101 L/S Ratio 35 43 52 TDS/EC ratio 0.307 0.275 0.269

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105 Appendix C (continued) Table C 5: Continued Mass of Ash = 13.4054 g Extraction Number 7th 8th 9th Date of Extraction: 12-Aug-04 15-Aug-04 18-Aug-04 mL of H2O 800.5 29.0 908.7 30.5 1020.3 39.3 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 330 106 277 64 203 42 Aluminum (mg/L) 1.673 0.792 2.657 0.944 3.217 0.717 Bromide (mg/L) BDL BDL BDL BDL BDL BDL Calcium (mg/L) 133 42 117 27 86 15 Carbonate (mg/L) 198 63 166 39 122 25 Chloride (mg/L) 9 4 6 2 5 2 Conductivity (mS/cm) 1.41 0.44 1.13 0.26 0.83 0.18 Copper (mg/L) 0.059 0.045 0.068 0.042 0.034 0.035 Fluoride (mg/L) BDL 1.07 0.01 0.56 Hardness (mg CaCO3 / L) 333 104 292 66 215 38 Iron (mg/L) 0.132 0.017 0.140 0.017 0.140 0.013 Magnesium (mg/L) 0.037 0.019 0.068 0.037 0.038 0.006 Manganese (mg/L) BDL BDL BDL BDL BDL BDL Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -34 7 -36 3 -33 5 pH 11.13 0.15 11.11 0.12 10.74 0.12 Phosphate (mg/L) 1.76 0.15 1.74 0.12 1.06 0.15 Potassium (mg/L) 1.5 0.8 1.1 0.5 3.5 3.2 Silica (mg/L as SiO2) 4.3 0.3 5.2 0.5 5.5 0.4 Sodium (mg/L) 3.1 1.5 3.4 1.0 2.4 1.1 Solids (TDS) mg/L 363 118 330 44 287 35 Sulfate (mg/L) 14.9 3.4 20.1 6.6 22.7 3.8 Temperature (C) 27.30 0.26 26.67 0.06 27.70 0.26 Total Nitrogen (mg/L as N) 0.8 0.4 0.6 0.2 0.4 0.1 Total Phosphorous (mg/L as PO4) 0.9 0.2 1.1 0.6 1.2 0.2 Zinc (mg/L) 0.183 0.039 0.182 0.034 0.147 0.026 TDS Value 363 330 287 mass (dissolved) 370 327 254 % identified 102 99 89 L/S Ratio 60 68 76 TDS/EC ratio 0.258 0.291 0.344

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106 Appendix C (continued) Table C 5: Continued Mass of Ash = 13.4054 g Extraction Number 10th 11th 12th Date of Extraction: 21-Aug-04 24-Aug-04 27-Aug-04 mL of H2O 1132.8 43.2 1247.8 51.8 1362.3 52.1 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 167 31 157 21 127 12 Aluminum (mg/L) 3.673 0.556 4.593 0.597 4.487 0.571 Bromide (mg/L) BDL 0.2 0.0 0.6 Calcium (mg/L) 75 8 78 8 69 8 Carbonate (mg/L) 100 18 94 12 76 7 Chloride (mg/L) 5 2 4 3 3 2 Conductivity (mS/cm) 0.71 0.13 0.65 0.09 0.60 0.07 Copper (mg/L) 0.035 0.028 0.085 0.005 0.046 0.001 Fluoride (mg/L) BDL BDL BDL Hardness (mg CaCO3 / L) 187 21 196 21 172 21 Iron (mg/L) 0.123 0.014 0.145 0.050 0.145 0.024 Magnesium (mg/L) 0.053 0.002 0.227 0.108 0.143 0.120 Manganese (mg/L) BDL BDL BDL BDL BDL BDL Nitrate (mg/L) BDL 1.04 BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -26 4 1 2 31 2 pH 11.10 0.10 11.04 0.10 10.69 0.07 Phosphate (mg/L) 0.99 0.12 0.93 0.03 0.85 0.02 Potassium (mg/L) 3.8 5.3 4.3 6.3 3.2 5.0 Silica (mg/L as SiO2) 4.6 0.2 7.5 1.6 4.5 0.4 Sodium (mg/L) 2.3 0.7 1.9 0.7 1.6 0.6 Solids (TDS) mg/L 230 0 240 10 253 12 Sulfate (mg/L) 30.8 8.9 34.4 4.0 38.7 3.0 Temperature (C) 27.50 0.46 25.83 0.06 31.13 0.49 Total Nitrogen (mg/L as N) 0.3 0.1 0.2 0.2 0.2 0.1 Total Phosphorous (mg/L as PO4) 1.3 0.4 0.6 0.1 1.0 0.5 Zinc (mg/L) 0.133 0.013 0.256 0.092 0.182 0.073 TDS Value 230 240 253 mass (dissolved) 228 232 204 % identified 99 97 80 L/S Ratio 85 93 102 TDS/EC ratio 0.324 0.369 0.425

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107 Appendix C (continued) Table C 6: Pasco Sequential Extraction Data, Averages and Standard Deviations Mass of Ash = 13.5983g Extraction Number 1st 2nd 3rd Date of Extraction: 19-Jul-04 22-Jul-04 25-Jul-04 mL of H2O 140 0 262 5 369 5 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 1167 47 907 57 587 58 Aluminum (mg/L) 0.333 0.197 0.190 0.105 0.130 0.070 Bromide (mg/L) 30.1 3.6 5.6 1.3 BDL Calcium (mg/L) 1167 87 505 48 283 35 Carbonate (mg/L) 700 28 544 34 352 35 Chloride (mg/L) 1463 146 203 38 60 9 Conductivity (mS/cm) 10.39 0.62 4.82 0.38 2.55 0.16 Copper (mg/L) 0.081 0.032 BDL BDL Fluoride (mg/L) BDL 1.39 0.03 1.26 0.13 Hardness (mg CaCO3 / L) 2915 218 1260 119 707 87 Iron (mg/L) 0.103 0.079 0.081 0.016 0.086 0.018 Magnesium (mg/L) 0.081 0.027 0.063 0.012 0.157 0.143 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) BDL 4.59 0.93 5.14 2.24 Nitrite (mg/L) BDL BDL BDL ORP (mV) -151 18 -84 10 pH 11.71 0.03 11.55 0.08 11.73 0.12 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 149.8 14.9 27.6 4.1 7.5 1.7 Silica (mg/L as SiO2) 0.3 0.2 0.5 0.4 2.3 0.1 Sodium (mg/L) 255.5 39.7 40.9 8.5 11.8 2.0 Solids (TDS) mg/L 5060 422 1967 216 990 199 Sulfate (mg/L) 320.3 34.4 166.9 19.9 113.6 19.6 Temperature (C) 26.77 0.32 27.70 0.10 25.03 0.55 Total Nitrogen (mg/L as N) 26.7 20.3 10.0 1.0 6.7 1.5 Total Phosphorous (mg/L as PO4) 0.0 0.0 0.0 0.0 0.0 0.0 Zinc (mg/L) 2.786 0.364 0.858 0.214 0.292 0.045 TDS Value 5060 1967 990 mass (dissolved) 4117 1510 843 % identified 81 77 85 L/S Ratio 10 19 27 TDS/EC ratio 0.487 0.408 0.389

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108 Appendix C (continued) Table C 6: Continued Mass of Ash = 13.5983g Extraction Number 4th 5th 6th Date of Extraction: 28-Jul-04 31-Jul-04 3-Aug-04 mL of H2O 460 19 552 33 657 37 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 407 71 280 56 213 29 Aluminum (mg/L) 0.340 0.125 0.923 0.379 1.467 0.415 Bromide (mg/L) 0.9 0.5 0.8 BDL Calcium (mg/L) 188 39 123 29 71 13 Carbonate (mg/L) 244 43 168 33 128 17 Chloride (mg/L) 42 27 23 6 8 3 Conductivity (mS/cm) 1.79 0.33 1.18 0.24 0.88 0.16 Copper (mg/L) BDL BDL BDL Fluoride (mg/L) 1.13 0.02 1.09 0.03 1.06 0.02 Hardness (mg CaCO3 / L) 470 97 308 71 178 33 Iron (mg/L) 0.088 0.037 0.169 0.040 0.187 0.059 Magnesium (mg/L) 0.107 0.048 0.160 0.117 0.086 0.034 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) 2.63 1.76 2.65 1.95 1.62 0.89 Nitrite (mg/L) BDL BDL BDL ORP (mV) -64 7 -50 12 -38 6 pH 11.43 0.11 11.58 0.12 10.84 0.12 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 4.0 2.0 3.1 2.0 1.5 0.8 Silica (mg/L as SiO2) 2.9 1.1 4.5 0.4 5.6 0.7 Sodium (mg/L) 7.6 2.6 5.5 2.1 3.7 2.0 Solids (TDS) mg/L 570 125 393 90 287 70 Sulfate (mg/L) 68.3 15.3 46.1 9.4 35.6 4.8 Temperature (C) 23.83 0.64 23.13 1.17 25.43 1.27 Total Nitrogen (mg/L as N) 8.3 2.1 0.7 0.3 0.9 0.2 Total Phosphorous (mg/L as PO4) 0.0 0.0 0.0 0.0 0.0 0.0 Zinc (mg/L) 0.222 0.032 0.205 0.045 0.134 0.029 TDS Value 570 393 287 mass (dissolved) 571 380 258 % identified 100 97 90 L/S Ratio 34 41 48 TDS/EC ratio 0.318 0.333 0.327

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109 Appendix C (continued) Table C 6: Continued Mass of Ash = 13.5983g Extraction Number 7th 8th 9th Date of Extraction: 6-Aug-04 9-Aug-04 12-Aug-04 mL of H2O 772 37 889 39 1003 41 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 167 25 133 12 120 10 Aluminum (mg/L) 2.383 0.227 2.687 0.506 3.040 0.140 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 65 11 59 5 53 7 Carbonate (mg/L) 100 15 80 7 72 6 Chloride (mg/L) 6 4 2 0 2 0 Conductivity (mS/cm) 0.67 0.09 0.63 0.05 0.47 0.06 Copper (mg/L) BDL BDL BDL Fluoride (mg/L) 0.57 0.02 0.57 0.00 0.56 0.01 Hardness (mg CaCO3 / L) 163 26 149 13 134 16 Iron (mg/L) 0.228 0.005 0.239 0.018 0.313 0.105 Magnesium (mg/L) 0.269 0.073 0.171 0.070 0.151 0.091 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) 1.14 0.46 0.90 0.36 0.63 0.26 Nitrite (mg/L) BDL BDL BDL ORP (mV) -44 5 -28 4 -4 5 pH 10.58 0.08 10.93 0.04 10.80 0.08 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 0.7 0.3 0.4 0.2 0.3 0.1 Silica (mg/L as SiO2) 6.3 0.6 6.6 0.4 5.9 1.0 Sodium (mg/L) 1.7 1.1 1.5 0.2 1.0 0.3 Solids (TDS) mg/L 250 20 210 20 190 20 Sulfate (mg/L) 37.2 2.7 39.5 3.0 37.8 5.0 Temperature (C) 26.10 0.20 28.00 0.10 24.87 0.31 Total Nitrogen (mg/L as N) 1.0 0.5 0.7 0.3 0.1 0.0 Total Phosphorous (mg/L as PO4) 0.0 0.0 0.0 0.0 0.0 0.0 Zinc (mg/L) 0.222 0.044 0.164 0.045 0.156 0.038 TDS Value 250 210 190 mass (dissolved) 222 195 177 % identified 89 93 93 L/S Ratio 57 65 74 TDS/EC ratio 0.375 0.335 0.402

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110 Appendix C (continued) Table C 6: Continued Mass of Ash = 13.5983g Extraction Number 10th 11th 12th Date of Extraction: 15-Aug-04 18-Aug-04 21-Aug-04 mL of H2O 1107 29 1221 30 1340 30 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 117 6 107 6 107 6 Aluminum (mg/L) 2.993 0.341 3.047 0.742 3.867 0.729 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 55 5 48 6 50 6 Carbonate (mg/L) 70 3 64 3 64 3 Chloride (mg/L) 6 6 2 0 2 0 Conductivity (mS/cm) 0.49 0.03 0.46 0.04 0.45 0.04 Copper (mg/L) BDL BDL BDL Fluoride (mg/L) 0.55 0.01 0.56 0.01 0.56 0.00 Hardness (mg CaCO3 / L) 138 12 120 14 127 14 Iron (mg/L) 0.381 0.060 0.044 BDL Magnesium (mg/L) 0.129 0.037 0.112 0.052 0.498 0.195 Manganese (mg/L) BDL BDL BDL Nitrate (mg/L) 0.53 0.04 0.49 0.07 0.48 Nitrite (mg/L) BDL BDL BDL ORP (mV) -16 3 -1 1 2 1 pH 10.78 0.08 10.64 0.06 11.02 0.07 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 0.2 0.1 0.2 0.1 0.1 0.0 Silica (mg/L as SiO2) 5.6 1.5 5.9 1.6 6.3 1.7 Sodium (mg/L) 0.6 0.2 0.7 0.1 0.7 0.2 Solids (TDS) mg/L 177 23 200 10 170 17 Sulfate (mg/L) 37.8 4.0 33.9 4.5 34.5 4.0 Temperature (C) 25.23 0.40 27.90 0.17 28.40 0.10 Total Nitrogen (mg/L as N) 0.0 0.0 0.2 0.1 0.1 0.1 Total Phosphorous (mg/L as PO4) 0.0 0.0 0.0 0.0 0.0 0.0 Zinc (mg/L) 0.138 0.026 0.132 0.021 0.349 0.116 TDS Value 177 200 170 mass (dissolved) 180 159 163 % identified 102 79 96 L/S Ratio 81 90 99 TDS/EC ratio 0.364 0.438 0.377

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111 Appendix C (continued) Table C 7: Fly Ash Sequential Extraction Data, Averages and Standard Deviations Mass of Ash = 13.7065g Extraction Number 1st 2nd 3rd Date of Extraction: 4-Jun-04 7-Jun-04 10-Jun-04 mL of H2O 135 0 233 7 333 7 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 1303 25 1343 78 1233 311 Aluminum (mg/L) 0.020 0.035 0.057 0.055 0.190 0.104 Bromide (mg/L) 177.2 9.6 76.5 13.5 17.3 3.1 Calcium (mg/L) 5638 231 2179 226 892 119 Carbonate (mg/L) 782 15 806 47 740 186 Chloride (mg/L) 7652 257 3051 519 666 102 Conductivity (mS/cm) 33.10 0.17 16.02 1.38 7.85 1.16 Copper (mg/L) 0.175 0.017 0.101 0.010 0.080 0.014 Fluoride (mg/L) BDL BDL 4.29 0.12 Hardness (mg CaCO3 / L) 14078 577 5441 564 2228 298 Iron (mg/L) 0.313 0.070 0.201 0.167 0.159 0.085 Magnesium (mg/L) 0.291 0.075 0.104 0.034 0.073 0.034 Manganese (mg/L) 0.099 0.007 0.070 0.007 0.057 0.001 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -73 2 -85 5 -68 8 pH 11.16 0.04 11.59 0.09 11.98 0.12 Phosphate (mg/L) BDL BDL 5.83 0.52 Potassium (mg/L) 1163.8 44.4 300.9 69.6 68.0 15.6 Silica (mg/L as SiO2) 10.8 6.8 11.6 4.7 2.9 2.4 Sodium (mg/L) 1834.0 107.0 553.3 99.4 159.1 18.8 Solids (TDS) mg/L 18677 42 7300 849 2780 278 Sulfate (mg/L) 512.3 18.4 209.7 26.2 29.9 4.9 Temperature (C) 24.43 0.42 26.30 0.10 25.07 0.68 Total Nitrogen (mg/L as N) 0.2 0.1 0.3 0.0 0.2 0.1 Total Phosphorous (mg/L as PO4) 17.3 8.6 0.3 1.3 1.2 Zinc (mg/L) 2.338 0.221 1.450 0.053 0.800 0.110 TDS Value 18677 7300 2780 mass (dissolved) 15957 6637 2429 % identified 85 91 87 L/S Ratio 10 17 24 TDS/EC ratio 0.564 0.456 0.354

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112 Appendix C (continued) Table C 7: Continued Mass of Ash = 13.7065g Extraction Number 4th 5th 6th Date of Extraction: 13-Jun-04 16-Jun-04 19-Jun-04 mL of H2O 433 7 525 26 625 26 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 1047 193 1557 117 1067 81 Aluminum (mg/L) 0.047 0.045 0.233 0.108 0.380 0.080 Bromide (mg/L) 5.7 1.0 4.3 1.7 2.6 Calcium (mg/L) 562 52 539 66 545 49 Carbonate (mg/L) 628 116 934 70 640 48 Chloride (mg/L) 207 30 145 67 50 20 Conductivity (mS/cm) 5.15 0.61 6.94 0.60 4.89 0.34 Copper (mg/L) 0.066 0.006 0.072 0.005 0.062 0.000 Fluoride (mg/L) 3.11 0.60 4.44 0.20 2.87 0.71 Hardness (mg CaCO3 / L) 1404 130 1345 165 1360 123 Iron (mg/L) 0.164 0.060 0.054 0.031 0.221 0.085 Magnesium (mg/L) 0.041 0.027 0.063 0.019 0.053 0.046 Manganese (mg/L) 0.044 0.005 0.045 0.000 0.038 0.004 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -77 2 -100 0 -129 4 pH 12.26 0.14 12.32 0.05 12.05 0.07 Phosphate (mg/L) 5.37 0.49 4.53 0.47 3.83 0.44 Potassium (mg/L) 28.1 1.3 20.2 7.4 11.6 1.6 Silica (mg/L as SiO2) 1.1 0.4 4.1 2.1 1.1 0.3 Sodium (mg/L) 58.7 8.7 35.6 10.3 20.7 5.6 Solids (TDS) mg/L 1670 139 1827 224 1250 166 Sulfate (mg/L) 16.0 0.6 7.7 0.5 6.8 0.3 Temperature (C) 23.63 0.59 24.00 0.36 24.37 0.06 Total Nitrogen (mg/L as N) 0.1 0.1 0.2 0.1 0.3 0.2 Total Phosphorous (mg/L as PO4) 2.0 1.1 1.0 1.2 8.9 Zinc (mg/L) 0.471 0.014 0.744 0.078 0.448 0.083 TDS Value 1670 1827 1250 mass (dissolved) 1460 1665 1273 % identified 87 91 102 L/S Ratio 32 38 46 TDS/EC ratio 0.324 0.263 0.256

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113 Appendix C (continued) Table C 7: Continued Mass of Ash = 13.7065g Extraction Number 7th 8th 9th Date of Extraction: 22-Jun-04 25-Jun-04 28-Jun-04 mL of H2O 716 40 805 43 905 43 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 1073 114 850 101 767 90 Aluminum (mg/L) 0.640 0.100 0.607 0.031 0.937 0.225 Bromide (mg/L) 1.9 1.1 0.1 1.2 0.2 Calcium (mg/L) 517 74 429 30 347 41 Carbonate (mg/L) 644 68 510 61 460 54 Chloride (mg/L) 43 14 33 6 30 5 Conductivity (mS/cm) 4.88 0.48 4.02 0.32 3.36 0.44 Copper (mg/L) 0.071 0.016 0.058 0.009 0.076 0.019 Fluoride (mg/L) 5.81 0.57 7.20 1.08 4.61 0.73 Hardness (mg CaCO3 / L) 1292 185 1071 75 868 101 Iron (mg/L) 0.174 0.143 0.061 0.009 0.243 0.080 Magnesium (mg/L) 0.146 0.164 0.036 0.028 0.197 0.195 Manganese (mg/L) 0.047 0.009 0.038 0.001 0.035 0.008 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -100 9 -82 2 -68 1 pH 12.04 0.14 11.91 0.02 12.18 0.02 Phosphate (mg/L) 3.96 0.11 2.84 0.27 2.95 0.28 Potassium (mg/L) 10.4 2.1 10.9 1.9 6.0 4.3 Silica (mg/L as SiO2) 0.5 0.3 1.1 0.7 1.3 0.9 Sodium (mg/L) 17.7 4.4 16.7 1.1 8.1 4.1 Solids (TDS) mg/L 1237 131 973 71 790 131 Sulfate (mg/L) 9.6 1.3 9.6 1.4 16.9 5.5 Temperature (C) 24.90 0.72 23.70 0.17 25.43 0.38 Total Nitrogen (mg/L as N) 0.2 0.1 0.3 0.1 0.2 0.0 Total Phosphorous (mg/L as PO4) 7.6 BDL BDL Zinc (mg/L) 0.511 0.212 0.326 0.038 0.493 0.227 TDS Value 1237 973 790 mass (dissolved) 1246 1006 873 % identified 101 103 110 L/S Ratio 52 59 66 TDS/EC ratio 0.253 0.242 0.235

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114 Appendix C (continued) Table C 7: Continued Mass of Ash = 13.7065g Extraction Number 10th 11th 12th Date of Extraction: 1-Jul-04 4-Jul-04 10-Jul-04 mL of H2O 995 40 1095 40 1184 45 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 587 45 503 40 493 31 Aluminum (mg/L) 1.423 0.140 1.497 0.068 1.787 0.266 Bromide (mg/L) 1.2 0.2 1.3 0.1 1.5 0.1 Calcium (mg/L) 294 69 244 20 225 11 Carbonate (mg/L) 352 27 302 24 296 18 Chloride (mg/L) 23 4 26 2 22 1 Conductivity (mS/cm) 2.67 0.17 2.40 0.19 2.32 0.10 Copper (mg/L) 0.072 0.006 0.064 0.004 0.067 0.005 Fluoride (mg/L) 4.10 0.47 6.05 0.88 4.48 0.95 Hardness (mg CaCO3 / L) 735 172 609 51 563 28 Iron (mg/L) 0.127 0.019 0.166 0.032 0.134 0.023 Magnesium (mg/L) 0.096 0.105 0.034 0.016 0.067 0.046 Manganese (mg/L) 0.036 0.006 0.037 0.002 0.035 0.006 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -120 21 -69 6 -58 5 pH 12.06 0.04 11.93 0.05 11.61 0.13 Phosphate (mg/L) 3.05 0.04 2.10 0.22 2.22 0.12 Potassium (mg/L) 8.0 0.6 6.6 0.6 8.7 0.5 Silica (mg/L as SiO2) 1.9 0.3 2.3 0.4 3.2 0.4 Sodium (mg/L) 0.8 0.3 2.5 2.0 3.7 2.2 Solids (TDS) mg/L 667 143 597 40 587 40 Sulfate (mg/L) 18.2 3.1 18.7 3.8 24.9 4.8 Temperature (C) 26.37 0.25 25.33 0.47 25.20 0.10 Total Nitrogen (mg/L as N) BDL BDL BDL Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.344 0.135 0.240 0.022 0.282 0.058 TDS Value 667 597 587 mass (dissolved) 708 611 591 % identified 106 102 101 L/S Ratio 73 80 86 TDS/EC ratio 0.250 0.248 0.253

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115 Appendix C (continued) Table C 7: Continued Mass of Ash = 13.7065g Extraction Number 13th 14th Date of Extraction: 13-Jul-04 16-Jul-04 mL of H2O 1284 45 1381 57 Test Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 390 20 390 36 Aluminum (mg/L) 2.307 0.146 2.080 0.132 Bromide (mg/L) 1.0 0.0 1.1 0.1 Calcium (mg/L) 178 14 185 13 Carbonate (mg/L) 234 12 234 22 Chloride (mg/L) 14 1 15 1 Conductivity (mS/cm) 1.76 0.08 1.78 0.11 Copper (mg/L) 0.066 0.002 0.066 0.010 Fluoride (mg/L) 5.83 0.56 7.30 0.55 Hardness (mg CaCO3 / L) 446 34 462 34 Iron (mg/L) 0.150 0.082 0.098 0.042 Magnesium (mg/L) 0.062 0.054 0.033 0.003 Manganese (mg/L) 0.042 0.003 0.043 0.002 Nitrate (mg/L) BDL BDL Nitrite (mg/L) BDL BDL ORP (mV) -56 4 -57 3 pH 11.66 0.05 11.53 0.03 Phosphate (mg/L) 1.90 0.10 2.13 0.12 Potassium (mg/L) 5.9 0.8 7.0 5.3 Silica (mg/L as SiO2) 4.2 0.5 1.6 0.6 Sodium (mg/L) 1.3 1.1 0.3 0.1 Solids (TDS) mg/L 483 21 447 31 Sulfate (mg/L) 25.2 3.1 19.7 1.2 Temperature (C) 25.30 0.46 25.23 0.31 Total Nitrogen (mg/L as N) BDL BDL Total Phosphorous (mg/L as PO4) BDL BDL Zinc (mg/L) 0.258 0.058 0.211 0.009 TDS Value 483 447 mass (dissolved) 474 475 % identified 98 106 L/S Ratio 94 101 TDS/EC ratio 0.274 0.251

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116 Appendix C (continued) Table C 8: Bottom Ash Sequential Extraction Data, Averages and Standard Deviations Mass of Ash = 13.6278g Extraction Number 1st 2nd 3rd Date of Extraction: 4-Jun-04 7-Jun-04 10-Jun-04 mL of H2O 135 0 252 3 352 3 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 637 160 490 53 583 93 Aluminum (mg/L) 11.86 13.68 7.23 8.88 8.67 12.29 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 411 82 308 39 267 73 Carbonate (mg/L) 382 96 294 32 350 56 Chloride (mg/L) 34.7 5.5 16.8 2.2 10.5 2.1 Conductivity (mS/cm) 4.18 0.69 3.22 0.44 2.70 0.57 Copper (mg/L) 0.442 0.102 0.180 0.049 0.191 0.051 Fluoride (mg/L) BDL BDL 0.41 0.15 Hardness (mg CaCO3 / L) 1029 206 770 96 667 182 Iron (mg/L) 0.666 0.478 0.156 0.065 0.208 0.078 Magnesium (mg/L) 0.764 0.334 0.054 0.026 0.118 0.045 Manganese (mg/L) 0.143 0.136 0.034 0.002 0.034 0.003 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -180 55 -159 43 -150 48 pH 12.08 0.06 12.22 0.05 11.99 0.10 Phosphate (mg/L) BDL BDL 0.82 Potassium (mg/L) 51.4 62.2 14.8 19.2 5.8 7.2 Silica (mg/L as SiO2) 5.3 3.7 0.7 0.4 1.5 1.2 Sodium (mg/L) 60.6 19.0 12.3 3.7 6.2 2.6 Solids (TDS) mg/L 1023 240 707 95 640 131 Sulfate (mg/L) 15.7 19.4 24.9 33.0 33.9 50.2 Temperature (C) 25.23 0.21 26.27 0.12 25.27 0.29 Total Nitrogen (mg/L as N) 2.3 0.4 0.8 0.1 0.6 0.3 Total Phosphorous (mg/L as PO4) BDL 11.4 0.3 0.2 Zinc (mg/L) 1.021 1.123 0.266 0.072 0.254 0.096 TDS Value 1023 707 640 mass (dissolved) 978 692 686 % identified 96 98 107 L/S Ratio 10 18 26 TDS/EC ratio 0.245 0.220 0.237

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117 Appendix C (continued) Table C 8: Continued Mass of Ash = 13.6278g Extraction Number 4th 5th 6th Date of Extraction: 13-Jun-04 16-Jun-04 19-Jun-04 mL of H2O 452 3 552 3 652 3 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 460 120 363 85 233 23 Aluminum (mg/L) 10.27 13.84 16.98 22.74 16.55 16.82 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 210 66 151 35 97 20 Carbonate (mg/L) 276 72 218 51 140 14 Chloride (mg/L) 13.4 9.2 5.5 2.6 3.4 1.9 Conductivity (mS/cm) 1.89 0.49 1.47 0.37 0.97 0.17 Copper (mg/L) 0.164 0.049 0.145 0.037 0.108 0.023 Fluoride (mg/L) 0.30 0.15 0.28 0.12 0.42 0.39 Hardness (mg CaCO3 / L) 525 165 377 86 244 51 Iron (mg/L) 0.240 0.006 0.318 0.097 0.272 0.035 Magnesium (mg/L) 0.101 0.042 0.087 0.038 0.032 0.009 Manganese (mg/L) 0.037 0.002 0.034 0.002 0.034 0.003 Nitrate (mg/L) 0.10 BDL 0.02 Nitrite (mg/L) BDL BDL BDL ORP (mV) -108 21 -114 26 -154 15 pH 11.85 0.34 12.04 0.14 10.98 0.29 Phosphate (mg/L) 0.82 0.40 0.43 0.01 Potassium (mg/L) 2.6 2.7 1.9 1.8 1.2 1.2 Silica (mg/L as SiO2) 1.6 0.6 2.2 0.9 2.2 0.9 Sodium (mg/L) 2.9 1.5 2.9 1.7 3.1 1.6 Solids (TDS) mg/L 530 130 433 76 320 61 Sulfate (mg/L) 28.1 36.1 29.8 32.4 26.0 24.3 Temperature (C) 22.63 0.15 23.43 0.47 23.67 0.40 Total Nitrogen (mg/L as N) 0.4 0.2 0.4 0.2 0.2 0.2 Total Phosphorous (mg/L as PO4) 1.6 0.2 1.7 1.5 1.4 0.1 Zinc (mg/L) 0.213 0.039 0.230 0.101 0.130 0.022 TDS Value 530 433 320 mass (dissolved) 549 431 293 % identified 104 100 92 L/S Ratio 33 40 48 TDS/EC ratio 0.281 0.296 0.330

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118 Appendix C (continued) Table C 8: Continued Mass of Ash = 13.6278g Extraction Number 7th 8th 9th Date of Extraction: 22-Jun-04 25-Jul-04 28-Jun-04 mL of H2O 752 3 852 3 952 3 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 217 15 193 35 177 35 Aluminum (mg/L) 20.97 20.86 22.92 20.20 23.20 20.81 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 85 20 77 15 68 15 Carbonate (mg/L) 130 9 116 21 106 21 Chloride (mg/L) 2.8 1.9 5.4 3.9 1.6 1.0 Conductivity (mS/cm) 0.86 0.14 0.66 0.08 0.55 0.22 Copper (mg/L) 0.084 0.064 0.112 0.014 0.109 0.012 Fluoride (mg/L) 0.19 0.06 0.33 0.20 0.33 0.23 Hardness (mg CaCO3 / L) 212 49 192 37 171 38 Iron (mg/L) 0.353 0.037 0.368 0.063 0.454 0.093 Magnesium (mg/L) 0.063 0.007 0.095 0.021 0.066 0.021 Manganese (mg/L) 0.042 0.005 0.041 0.007 0.041 0.003 Nitrate (mg/L) BDL BDL 0.28 Nitrite (mg/L) BDL BDL BDL ORP (mV) -100 40 -64 30 -85 38 pH 10.81 0.19 11.36 0.07 11.74 0.07 Phosphate (mg/L) BDL BDL BDL Potassium (mg/L) 3.6 5.2 1.0 1.0 1.1 0.3 Silica (mg/L as SiO2) 3.2 1.0 2.2 0.6 7.2 4.2 Sodium (mg/L) 2.2 0.5 1.7 0.8 1.4 0.6 Solids (TDS) mg/L 270 26 280 36 220 36 Sulfate (mg/L) 38.0 28.4 33.7 25.5 39.5 30.8 Temperature (C) 24.90 0.40 22.77 0.15 24.80 0.26 Total Nitrogen (mg/L as N) 0.7 0.6 0.3 0.1 0.3 0.2 Total Phosphorous (mg/L as PO4) 0.6 0.3 BDL BDL Zinc (mg/L) 0.159 0.036 0.169 0.063 0.142 0.030 TDS Value 270 280 220 mass (dissolved) 288 261 250 % identified 107 93 114 L/S Ratio 55 62 70 TDS/EC ratio 0.315 0.425 0.402

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119 Appendix C (continued) Table C 8: Continued Mass of Ash = 13.6278g Extraction Number 10th 11th 12th Date of Extraction: 1-Jul-04 4-Jul-04 10-Jul-04 mL of H2O 1052 3 1159 3 1275 5 Test Average Std.Dev. Average Std.Dev. Average Std.Dev. Alkalinity (mg CaCO3 / L) 160 46 153 42 147 31 Aluminum (mg/L) 22.07 17.12 22.13 19.46 19.87 11.63 Bromide (mg/L) BDL BDL BDL Calcium (mg/L) 73 10 57 12 59 20 Carbonate (mg/L) 96 27 92 25 88 18 Chloride (mg/L) 1.2 0.9 1.1 0.6 0.5 0.5 Conductivity (mS/cm) 0.60 0.01 0.54 0.05 0.53 0.08 Copper (mg/L) 0.116 0.015 0.093 0.007 0.097 0.020 Fluoride (mg/L) 0.21 0.18 BDL 0.19 Hardness (mg CaCO3 / L) 182 26 141 30 147 51 Iron (mg/L) 0.539 0.063 0.468 0.023 0.557 0.037 Magnesium (mg/L) 0.095 0.042 0.057 0.012 0.086 0.046 Manganese (mg/L) 0.043 0.000 0.044 0.005 0.041 0.002 Nitrate (mg/L) BDL BDL BDL Nitrite (mg/L) BDL BDL BDL ORP (mV) -81 46 -81 36 -48 35 pH 11.44 0.11 11.47 0.06 11.25 0.07 Phosphate (mg/L) 0.40 0.73 BDL Potassium (mg/L) 0.2 BDL BDL Silica (mg/L as SiO2) 3.7 2.1 1.9 0.5 3.3 1.3 Sodium (mg/L) 0.9 0.3 0.6 0.3 0.7 0.2 Solids (TDS) mg/L 227 25 240 56 223 25 Sulfate (mg/L) 29.7 17.6 33.4 20.3 38.7 28.0 Temperature (C) 26.20 0.10 24.93 0.45 25.33 0.25 Total Nitrogen (mg/L as N) 1.1 3.5 2.8 BDL Total Phosphorous (mg/L as PO4) BDL BDL BDL Zinc (mg/L) 0.184 0.110 0.140 0.036 0.151 0.049 TDS Value 227 240 223 mass (dissolved) 229 213 211 % identified 101 89 94 L/S Ratio 77 85 94 TDS/EC ratio 0.380 0.447 0.420

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120 Appendix C (continued) Table C 8: Continued Mass of Ash = 13.6278g Extraction Number 13th Date of Extraction: 13-Jul-04 mL of H2O 1390 5 Test Average Std.Dev. Alkalinity (mg CaCO3 / L) 113 23 Aluminum (mg/L) 18.20 9.57 Bromide (mg/L) BDL Calcium (mg/L) 48 14 Carbonate (mg/L) 68 14 Chloride (mg/L) 0.4 0.3 Conductivity (mS/cm) 0.43 0.05 Copper (mg/L) 0.087 0.015 Fluoride (mg/L) BDL Hardness (mg CaCO3 / L) 120 34 Iron (mg/L) 0.508 0.102 Magnesium (mg/L) 0.042 0.006 Manganese (mg/L) 0.036 0.005 Nitrate (mg/L) BDL Nitrite (mg/L) BDL ORP (mV) -60 25 pH 11.17 0.12 Phosphate (mg/L) BDL Potassium (mg/L) BDL Silica (mg/L as SiO2) 2.9 0.3 Sodium (mg/L) 0.5 0.2 Solids (TDS) mg/L 227 61 Sulfate (mg/L) 30.0 20.1 Temperature (C) 24.63 0.12 Total Nitrogen (mg/L as N) BDL Total Phosphorous (mg/L as PO4) BDL Zinc (mg/L) 0.118 0.017 TDS Value 227 mass (dissolved) 169 % identified 74 L/S Ratio 102 TDS/EC ratio 0.529

PAGE 133

121 Appendix C (continued) Table C 9: Pasco County Ash Monofill Da ta, Averages and Standard Deviations Date: Oct. 22, 2004 Number 1 2 3 Avg. Std. Dev. Test Alkalinity (mg CaCO3 / L) 140 140 140 140 0 Aluminum (mg/L) 0.200 0.240 0.400 0.280 0.106 Bromide (mg/L) BDL 249 BDL 249 Calcium (mg/L) 5341 5371 5440 5384 50 Carbonate (mg/L) 84 84 84 84 0 Chloride (mg/L) 9400 8163 9987 9183 931 Conductivity (mS/cm) 44.00 44.10 44.00 44.03 0.06 Copper (mg/L) 0.390 0.430 0.420 0.413 0.021 Fluoride (mg/L) BDL BDL BDL BDL Hardness (mg CaCO3 / L) 13356 13430 13602 13462 126 Iron (mg/L) 6.130 7.750 7.190 7.023 0.823 Magnesium (mg/L) 4.580 4.710 4.660 4.650 0.066 Manganese (mg/L) 0.680 0.710 0.630 0.673 0.040 Nitrate (mg/L) BDL BDL BDL BDL Nitrite (mg/L) BDL BDL BDL BDL ORP (mV) 32 28 21 27 6 pH 5.86 5.64 5.92 5.81 0.15 Phosphate (mg/L) BDL BDL BDL BDL Potassium (mg/L) 1771.9 1787.8 1774.0 1777.9 8.6 Silica (mg/L as SiO2) 1.2 1.3 0.9 1.1 0.2 Sodium (mg/L) 2464.2 2422.0 3225.5 2703.9 452.2 Solids (TDS) mg/L 25000 24965 24983 25 Sulfate (mg/L) 522 502 528 517 14 Temperature (C) 28.60 28.50 28.50 28.53 0.06 TOC (mg/L as C) 7.29 7.35 7.32 7.32 0.03 Total Nitrogen (mg/L as N) 27.5 26.5 15.4 23.1 6.7 Total Phosphorous (mg/L as PO4) 12.8 9.2 11.0 2.5 Zinc (mg/L) 0.190 0.180 0.180 0.183 0.006 TDS Value 25000.00 24965.00 24982.50 mass (dissolved) 19636.97 18629.42 19947.72 % identified 78.55 74.62 79.85 TDS/EC ratio 0.568182 0.5660998 0.5673543


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Rhea, Lisa R.
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Mineral solubilization from municipal solid waste combustion residues
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implications for landfill leachate collection systems /
by Lisa R. Rhea.
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[Tampa, Fla.] :
University of South Florida,
2004.
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Thesis (M.S.Env.E.)--University of South Florida, 2004.
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Includes bibliographical references.
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Text (Electronic thesis) in PDF format.
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ABSTRACT: Leachate collection systems consist of a series of pipes installed beneath the waste at the base of a landfill. The liquid drains toward a central location where it is pumped and then treated, discharged, or recirculated. In some landfills, solid precipitates form in the collection system resulting in clogging and malfunctions of the drainage system. The formation of the precipitates is linked to the chemical and biological stability of the leachate generated within the landfill. To control the formation of precipitates and prevent clogging of leachate collection systems, it is important to understand factors that influence leachate characteristics. Ashes from municipal solid waste (MSW) combustion are either placed in monofills or combined with traditional solid waste, and sludges and biosolids from wastewater and drinking water treatment plants when landfilled.The ashes, depending on the type of combustion process, contain high concentrations of metals and non-biodegradable materials. As the waste degrades, oxygen in the landfill is consumed and the leachate becomes anaerobic. The reducing environment allows for greater solubility of metals. This research tested ashes from three different Waste-to-Energy (WTE) facilities to understand better the role MSW fly ash and MSW bottom ash in the chemical make-up of landfill leachate. Two different types of batch tests were used to analyze the leaching behavior. First, a contact time batch test with a range of different contact times was used to assess the rate at which different elements reach equilibrium. This was followed by a sequential extraction batch test that predicted the total amount of soluble material in the ashes.The chemical characteristics of the leachate produced by the ashes were understood and the leaching behaviors analyzed, dominant chemical factors that influence the formation of precipitates were identified. This data produced a better understanding of the roles of WTE ashes in the production of precipitates in leachate collection systems.
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Adviser: Levine, Audrey D.
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batch tests.
clogging.
deposition.
precipitates.
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