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Effect of hydraulic retention time on landfill leachate and gas characteristics Munasinghe, Ranjani 1997-12-31

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EFFECT OF HYDRAULIC RETENTION TIME ON LANDFILL LEACHATE AND GAS CHARACTERISTICS by Ranjani Munasinghe B.Sc. (Hons), Peradeniya, Sri Lanka; M.Eng., Bangkok, Thailand A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES CIVIL ENGINEERING We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA August 1997 © Ranjani Munasinghe, 1997 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Civil Engineering The University of British Columbia Vancouver, Canada Date: A.^.g^....M..>.(^'? Abstract Previous field studies carried out in order to characterize leachate in Vancouver, B.C. landfills show an effect of water input patterns on leachate characteristics. With high rain fall into the landfills, high volatile fatty acid (VFA) concentrations appear in leachate. It is postulated that with high rainfall there is a reduction in hydraulic retention time (HRT) which results in a reduction in the conversion of VFA to CH4 and CC>2- Coincidence of peak infiltration rates with high dissolved organic carbon concentrations greatly increases the pollutant loadings to the treatment plants. The objective of the study was to investigate the effects of HRT on landfill leachate and gas characteristics. HRTs from 3 to 200 days were assigned to eighteen lab scale lysimeters during four experimental phases in which the HRT was changed by changing the infiltration rates through the lysimeters. A relationship was established between HRT and infiltration rate in refuse columns and tested using tracer studies. For unsaturated landfills; S HRT = — Q Where; S = Volumetric water holding capacity of the solid waste in the landfill X Volume of the solid waste in the landfill (L3) Q = Flow rate through the landfill (L3T_1) Percent CH4 concentration in gas decreased with increasing HRT up to 60 days. ii Lower HRTs showed higher CH4 productions and increase in CH4 concentration indi cating enhanced methanogenesis. High gas producing columns increased their pH with time from values less than 5.5 irrespective of the changes in HRT. Decrease in HRT helped the columns with low gas production and pH less than 5.3 to increase their pH which is favorable for methanogen esis. When HRT was decreased in columns with high gas production and pH higher than 5.8, a slight decrease in pH was observed with a substantial decrease in CO2 concentra tion in gas, but no detrimental effect on gas production was observed. Gas production itself helps in developing favorable conditions for biological degradation; it increases pH, produces alkalinity when VFAs are consumed, responds favorably to changes in HRT, reduces inhibitive concentrations of VFAs and other organics and inorganics in the mi-croenvironments. The amount of total carbon released to the environment is highly dependent on gas production. High gas producing columns released 50% more carbon than low gas pro ducing columns. Continuous mobilization of zinc and iron occurred throughout the experiment. Zinc concentrations showed inconsistent correlation to either pH or methane production rate. Correlation of iron concentrations to pH and CH4 production rate showed dependence on HRT and CH4 production stage of the column. The high VFA concentrations observed in field studies are not, based on this study likely to be due to the failure of methanogenesis because of high water inputs contrary to the original hypothesis. During phase I under similar HRT conditions, there was considerable variability in methane production from the lysimeters that could not be explained. iii Table of Contents Abstract ii List of Figures x List of Tables xx nomenclature xxii Acknowledgment xxii1 Introduction 1 2 Background and Literature Review 4 2.1 Introduction 4 2.2 Landfill Characteristics2.3 Leachate Production2.3.1 Hydrological Balance in Landfills 5 2.3.2 Field Capacity 7 2.3.3 Moisture Flow Through the Refuse 7 2.4 Landfill Gas Production and Characteristics 10 2.4.1 Decomposition of Refuse 12.5 Factors Affecting Waste Decomposition 12 2.5.1 Oxygen 12.5.2 Hydrogen 4 iv 2.5.3 pH and Alkalinity 14 2.5.4 Sulfate 15 2.5.5 Nutrients2.5.6 Inhibitors 6 2.5.7 Temperature 17 2.5.8 Moisture/Water Content 18 2.6 Landfill Leachate Characteristics 20 2.7 Change in Landfill Gas and Leachate Characteristics with Time 20 2.8 Effects of Infiltration of Water through Refuse 26 2.9 Effects of Rainfall Pattern on Landfill Leachate and Gas Characteristics . 26 2.10 Landfill Stabilization 30 2.11 Hydraulic Retention Time of Landfills 32.12 Present Trends in Landfill Management and Timing of the Research ... 33 2.13 Summary 34 3 Objectives 6 4 Experimental Methods and Analytical Procedures 38 4.1 Experimental Set-up 38 4.1.1 Construction of Lysimeters 38 4.1.2 Filling of Refuse in the Columns 40 4.1.3 Preparation of Columns for the Study 3 4.2 Selection of HRTs for the Study 44.3 Methodology-Phase I 46 4.4 Methodology-Phase II4.5 Methodology-Phase III 8 4.6 Methodology-Phase IV 49 v 4.7 Tracer Experiments 50 4.8 Analytical Procedures 1 4.8.1 PH4.8.2 Volatile Fatty Acids (VFAs) 51 4.8.3 Chemical Oxygen Demand (COD) 52 4.8.4 Total Organic Carbon (TOC) and Inorganic Carbon (IC) 52 4.8.5 Alkalinity 54.8.6 Specific Conductance 53 4.8.7 Solids4.8.8 Nitrogen 54.8.9 Metals 4 4.8.10 Chloride4.8.11 Gas Analysis 55 4.9 Statistics5 Results and Discussion 56 5.1 Introduction5.2 Hydraulic Retention Time for Landfills 58 5.2.1 Tracer Experiments 61 5.3 General Characteristics of Landfill Gas (Phase I) 70 5.3.1 Methane potential of the Refuse Columns 96 5.4 Effect of HRT on Landfill Gas Characteristics (Phases II, III and IV) . . 101 5.5 General Characteristics of Leachate (Phase I) 107 5.6 Effect of HRT on Landfill Leachate (Phase II and III) 107 5.6.1 pH 108 5.6.2 Volatile Fatty Acids (VFA) 113 vi 5.6.3 Chemical Oxygen Demand (COD) 126 5.6.4 Total Organic Carbon (TOC) and Inorganic Carbon (IC) 128 5.6.5 Alkalinity 132 5.6.6 Specific Conductance 135 5.6.7 Total Solids 137 5.6.8 Nitrogen (NH3 - N, TKN) 139 5.6.9 Iron 143 5.6.10 Zinc5.6.11 Sodium 155.6.12 Chloride 5 5.7 Pollutant Release to the Environment from the Lysimeters 157 5.8 Micro-environments 163 5.9 Carbon Released to the Environment 164 5.9.1 Carbon in Leachate 165 5.9.2 Carbon in Gas 6 5.10 General Overview 191 5.11 Potential Applications of Findings 199 6 Conclusions and Future Work 206.1 Conclusions 209 6.2 Recommendations for Future Work 211 Bibliography 212 Appendices 9 A Calculation of 00% produced and Total Gas Production 219 A.l C02 Produced 220 vii A.1.1 For Samples with Low Dissolved Solids - Method 1 220 A. 1.2 Sample calculation 221 A.1.3 Total Gas Produced Calculated from Method 1 222 A. 1.4 For Samples with High Dissolved Solids - Method 2 223 A. 1.5 Sample Calculation 224 A. 1.6 Total Gas Produced Calculated from Method 2 225 B Regression Plots for Iron and pH 230 C Regression Plots for Iron and Methane Production Rate 239 D Regression Plots for Zinc and pH 248 E Regression Plots for Zinc and Methane Production Rate 257 F Leachate Characteristics Data 266 F.l pH 26F.2 Volatile Fatty Acids 267 F.3 Distribution of VFA types 268 F.4 Chemical Oxygen Demand 274 F.5 Total Organic Carbon 5 F.6 Inorganic Carbon 276 F.7 Alkalinity 277 F.8 Specific Conductance 278 F.9 Total Solids 279 F.10 TKN 280 F.ll Ammonia Nitrogen 281 F.12 Zinc 282 viii F.13 Iron 283 F.14 Sodium 4 F. 15 Chlorides 285 G Gas Characteristics Data 286 G. l Composition of GasG.2 Gas Production 291 ix List of Figures 2.1 Schematic of the General Hydrological Balance in a Completed Sanitary Landfill 6 2.2 Substrates and Major Bacterial Groups Involved in the Methane Gener ating Ecosystem 11 2.3 Major Abiotic Factors Affecting the Methane-generating Ecosystem . . 13 2.4 Illustration of Developments in Gas and Leachate Composition in a Land fill Cell 24 2.5 Summary of Observed Trends in Refuse Decomposition with Leachate Recycle 5 2.6 Stimulus-Response Techniques Commonly used to Study Flow in Reactors 32 4.1 Schematic of the Experimental Set-up 39 4.2 Schematic of a Wet Gas Meter 43 5.1 Tracer Response Curve for HRT=18 days 66 5.2 Tracer Response Curve for HRT=35 days5.3 Tracer Response Curve for HRT=60 days 67 5.4 Tracer Response Curve for HRT=120 days5.5 Tracer Response Curve for HRT=200 days 68 5.6 Comparison of Observed HRTs 65.7 Tracer Response Curve for column 16 69 5.8 Tracer Response Curves for Columns 7 and 10 at Different Stages of Decomposition 6x 5.9 Methane Production Rate in Columns 1-3 72 5.10 Methane Production Rate in Columns 4-6 3 5.11 Methane Production Rate in Columns 7-9 74 5.12 Methane Production Rate in Columns 10-12 5 5.13 Methane Production Rate in Columns 13-15 76 5.14 Methane Production Rate in Columns 16-18 7 5.15 Cumulative Methane Production in Columns 1-3 78 5.16 Cumulative Methane Production in Columns 4-65.17 Cumulative Methane Production in Columns 7-9 79 5.18 Cumulative Methane Production in Columns 10-12 79 5.19 Cumulative Methane Production in Columns 13-15 80 5.20 Cumulative Methane Production in Columns 16-18 80 5.21 Composition of Gas in Column 1 81 5.22 Composition of Gas in Column 25.23 Composition of Gas in Column 3 82 5.24 Composition of Gas in Column 45.25 Composition of Gas in Column 5 83 5.26 Composition of Gas in Column 65.27 Composition of Gas in Column 7 84 5.28 Composition of Gas in Column 85.29 Composition of Gas in Column 9 5 5.30 Composition of Gas in Column 10 85.31 Composition of Gas in Column 11 6 5.32 Composition of Gas in Column 12 85.33 Composition of Gas in Column 13 7 5.34 Composition of Gas in Column 14 8xi 5.35 Composition of Gas in Column 15 88 5.36 Composition of Gas in Column 165.37 Composition of Gas in Column 17 89 5.38 Composition of Gas in Column 185.39 Gas Production Rates in Columns 1-3 90 5.40 Gas Production Rates in Columns 4-6 1 5.41 Gas Production Rates in Columns 7-9 92 5.42 Gas Production Rates in Columns 10-12 3 5.43 Gas Production Rates in Columns 13-15 94 5.44 Gas Production Rates in Columns 16-18 5 5.45 Effect of HRT on CH4 Concentration in Landfill Gas 105 5.46 Comparison of Cumulative CH4 Production of Columns 2, 5 and 6 . . . 105 5.47 Comparison of Cumulative CH4 Production of Columns 15 and 1 . . . . 106 5.48 Comparison of Cumulative CH4 Production of Columns 12 and 13 . . . 106 5.49 Change in pH in Columns 11, 12 and 14 110 5.50 Change in pH in Columns 2, 7, 10, 13, 16 and 18 Ill 5.51 Change in pH in Columns 1, 3 and 4 Il5.52 Change in pH in Columns 5, 8 and 9 112 5.53 Change in pH in Columns 6, 15 and 17 115.54 Change in VFA in Columns 1-6 115 5.55 Change in VFA in Columns 7-12 6 5.56 Change in VFA in Columns 13-18 115.57 Distribution of VFAs in Column 1 7 5.58 Distribution of VFAs in Column 2 115.59 Distribution of VFAs in Column 3 8 5.60 Distribution of VFAs in Column 4 11xii 5.61 Distribution of VFAs in Column 5 119 5.62 Distribution of VFAs in Column 65.63 Distribution of VFAs in Column 7 120 5.64 Distribution of VFAs in Column 85.65 Distribution of VFAs in Column 9 121 5.66 Distribution of VFAs in Column 105.67 Distribution of VFAs in Column 11 122 5.68 Distribution of VFAs in Column 125.69 Distribution of VFAs in Column 13 123 5.70 Distribution of VFAs in Column 145.71 Distribution of VFAs in Column 15 124 5.72 Distribution of VFAs in Column 165.73 Distribution of VFAs in Column 17 125 5.74 Distribution of VFAs in Column 185.75 Change in COD in Columns 1-6 126 5.76 Change in COD in Columns 7-12 7 5.77 Change in COD in Columns 13-18 125.78 Change in TOC in Columns 1-6 9 5.79 Change in TOC in Columns 7-12 125.80 Change in TOC in Columns 13-18 130 5.81 Change in IC in Columns 1-65.82 Change in IC in Columns 7-12 131 5.83 Change in IC in Columns 13-185.84 Change in Alkalinity in Columns 1-6 133 5.85 Change in Alkalinity in Columns 7-12 135.86 Change in Alkalinity in Columns 13-18 134 xiii 5.87 HRT, pH and Alkalinity of the Leachate at Steady State 134 5.88 Change in Specific Conductance in Columns 1-6 135 5.89 Change in Specific Conductance in Columns 7-12 136 5.90 Change in Specific Conductance in Columns 13-18 136 5.91 Change in Total Solids in Columns 1-6 137 5.92 Change in Total Solids in Columns 7-12 138 5.93 Change in Total Solids in Columns 13-18 135.94 Change in TKN in Columns 1-6 140 5.95 Change in TKN in Columns 7-125.96 Change in TKN in Columns 13-18 141 5.97 Change in Ammonia Nitrogen in Columns 1-6 145.98 Change in Ammonia Nitrogen in Columns 7-12 142 5.99 Change in Ammonia Nitrogen in Columns 13-18 145.100 Change in Iron in Columns 1-6 147 5.101 Change in Iron in Columns 7-12 8 5.102 Change in Iron in Columns 13-18 145.103 Change in Zinc in Columns 1-6 151 5.104 Change in Zinc in Columns 7-12 2 5.105 Change in Zinc in Columns 13-18 155.106 Change in Sodium in Columns 1-6 3 5.107 Change in Sodium in Columns 7-12 154 5.108 Change in Sodium in Columns 13-185.109 Change in Chloride in Columns 1-6 155 5.110 Change in Chloride in Columns 7-12 6 5.111 Change in Chloride in Columns 13-18 15xiv 5.112 Comparison of COD with the COD Prediction Curve by Reitzal et al., 1992 161 5.113 Comparison of Chloride with the Chloride Prediction Curve by Reitzal et al., 1992 162 5.114 Comparison of NHz — N with the NHs — N Prediction Curve by Reitzal et al., 1992 165.115 Carbon Released to the Environment from Column 1 172 5.116 Carbon Released to the Environment from Column 2 . 173 5.117 Carbon Released to the Environment from Column 3 174 5.118 Carbon Released to the Environment from Column 4 175 5.119 Carbon Released to the Environment from Column 5 176 5.120 Carbon Released to the Environment from Column 6 177 5.121 Carbon Released to the Environment from Column 7 178 5.122 Carbon Released to the Environment from Column 8 179 5.123 Carbon Released to the Environment from Column 9 180 5.124 Carbon Released to the Environment from Column 10 181 5.125 Carbon Released to the Environment from Column 11 182 5.126 Carbon Released to the Environment from Column 12 183 5.127 Carbon Released to the Environment from Column 13 184 5.128 Carbon Released to the Environment from Column 14 185 5.129 Carbon Released to the Environment from Column 15 186 5.130 Carbon Released to the Environment from Column 16 187 5.131 Carbon Released to the Environment from Column 17 188 5.132 Carbon Released to the Environment from Column 18 189 5.133 Carbon Released to the Environment in Relation to the CH^ Production 190 xv A.l Comparison of Measured and Calculated Gas Production Rates for Col umn 1 226 A.2 Comparison of Measured and Calculated Gas Production Rates for Col umn 2 22A.3 Comparison of Measured and Calculated Gas Production Rates for Col umn 3 227 A.4 Comparison of Measured and Calculated Gas Production Rates for Col umn 4 22A.5 Comparison of Measured and Calculated Gas Production Rates for Col umn 12 228 A.6 Comparison of Measured and Calculated Gas Production Rates for Col umn 14 22A.7 Comparison of Measured and Calculated Gas Production Rates for Col umn 16 229 A. 8 Comparison of Measured and Calculated Gas Production Rates for Col umn 18 22B. 9 Iron Vs pH for Column 1 230 B.10 Iron Vs pH for Column 2B.ll Iron Vs pH for Column 3 231 B.12 Iron Vs pi I for Column 4B.13 Iron Vs pH for Column 5 232 B.14 Iron Vs pH for Column 6B.15 Iron Vs pH for Column 7 233 B.16 Iron Vs pH for Column 8B.17 Iron Vs pH for Column 9 234 xvi B.18 Iron Vs pH for Column 10 234 B.19 Iron Vs pH for Column 11 5 B.20 Iron Vs pi I for Column 12 23B.21 Iron Vs pH for Column 13 6 B.22 Iron Vs pi I for Column 14 . , 23B.23 Iron Vs pH for Column 15 7 B.24 Iron Vs pH for Column 16 23B.25 Iron Vs pH for Column 17 8 B. 26 Iron Vs pH for Column 18 23C. 27 Iron Vs Methane Production Rate for Column 1 239 C.28 Iron Vs Methane Production Rate for Column 2 23C.29 Iron Vs Methane Production Rate for Column 3 240 C.30 Iron Vs Methane Production Rate for Column 4 24C.31 Iron Vs Methane Production Rate for Column 5 241 C.32 Iron Vs Methane Production Rate for Column 6 24C.33 Iron Vs Methane Production Rate for Column 7 242 C.34 Iron Vs Methane Production Rate for Column 8 24C.35 Iron Vs Methane Production Rate for Column 9 243 C.36 Iron Vs Methane Production Rate for Column 10 243 C.37 Iron Vs Methane Production Rate for Column 11 244 C.38 Iron Vs Methane Production Rate for Column 12 244 C.39 Iron Vs Methane Production Rate for Column 13 245 C.40 Iron Vs Methane Production Rate for Column 14 245 C.41 Iron Vs Methane Production Rate for Column 15 246 C.42 Iron Vs Methane Production Rate for Column 16 246 xvii C.43 Iron Vs Methane Production Rate for Column 17 247 C. 44 Iron Vs Methane Production Rate for Column 18 247 D. 45 Zinc Vs pi I for Column 1 248 D.46 Zinc Vs pH for Column 2D.47 Zinc Vs pH for Column 3 249 D.48 Zinc Vs pi I for Column 4D.49 Zinc Vs pi I for Column 5 250 D.50 Zinc Vs pH for Column 6D.51 Zinc Vs pi I for Column 7 251 D.52 Zinc Vs pH for Column 8D.53 Zinc Vs pH for Column 9 252 D.54 Zinc Vs pH for Column 10D.55 Zinc Vs pi I for Column 11 253 D.56 Zinc Vs pH for Column 12D.57 Zinc Vs pH for Column 13 254 D.58 Zinc Vs pH for Column 14D.59 Zinc Vs pH for Column 15 255 D.60 Zinc Vs pli for Column 16D.61 Zinc Vs pH for Column 17 256 D. 62 Zinc Vs pi I for Column 18E. 63 Zinc Vs Methane Production Rate for Column 1 257 E.64 Zinc Vs Methane Production Rate for Column 2 25E.65 Zinc Vs Methane Production Rate for Column 3 258 E.66 Zinc Vs Methane Production Rate for Column 4 25E.67 Zinc Vs Methane Production Rate for Column 5 259 xviii E.68 Zinc Vs Methane Production Rate for Column 6 259 E.69 Zinc Vs Methane Production Rate for Column 7 260 E.70 Zinc Vs Methane Production Rate for Column 8 26E.71 Zinc Vs Methane Production Rate for Column 9 261 E.72 Zinc Vs Methane Production Rate for Column 10 261 E.73 Zinc Vs Methane Production Rate for Column 11 262 E.74 Zinc Vs Methane Production Rate for Column 12 262 E.75 Zinc Vs Methane Production Rate for Column 13 263 E.76 Zinc Vs Methane Production Rate for Column 14 263 E.77 Zinc Vs Methane Production Rate for Column 15 264 E.78 Zinc Vs Methane Production Rate for Column 16 264 E.79 Zinc Vs Methane Production Rate for Column 17 265 E.80 Zinc Vs Methane Production Rate for Column 18 265 xix List of Tables 2.1 Field Capacities for Unprocessed Refuse 8 2.2 Toxic Concentrations of Heavy Metals in Anaerobic Waste Treatment 17 2.3 Typical Leachate Constituent Concentrations for Landfills 21 2.4 Characteristics of Landfills with High Organic Carbon during High Water Input 28 4.1 Composition of Refuse 40 4.2 Characteristics of the Prepared Columns and Feed Water 44 4.3 Experimental Design for Phase II 47 4.4 Experimental Design for Phase III 8 4.5 Summary of Experimental Conditions During the Research 49 4.6 LiCl Mass used in Tracer Studies 50 5.1 Moisture Sorbed and S of the Columns 60 5.2 t, a2 and Percentage of Mass of Tracer Recovered 62 5.3 Comparison of Predicted and Observed HRTs 4 5.4 Comparison of CH4 Produced from the Columns 99 5.5 Comparison of CH4 Yields and Annual Production Rates 100 5.6 Comparison of CH± concentration before Phase III and after Phase IV . 103 5.7 Summary of Correlation Analysis of Iron Vs pH and CH4 Production Ratel46 5.8 Summary of Correlation Analysis of Zinc Vs pH and CH4 Production Rate 150 5.9 Mass of VFA, COD, TOC and Alkalinity Leached during Phases I and II 158 5.10 Mass of Conductivity, Total Solids, TKN and NH2- N Leached .... 159 xx 5.11 Mass of Iron, Zinc and Sodium Leached 160 5.12 Summary of Carbon Releases from the Landfill 169 5.13 Effect of HRT on pH and Iron Concentrations 196 5.14 Effect of HRT on VFA, COD, TOC, TS, Na and Specific Conductance . 197 5.15 Effect of HRT on TKN, NH3 - N and Zinc 198 xxi nomenclature Symbol Description CH4 Methane C02 Carbon Dioxide COD Chemical Oxygen Demand DLC Demolition Landclearing and Construction HRT Hydraulic Retention Time IC Inorganic Carbon MSW Municipal Solid Waste n Number of observations N2 Nitrogen NHZ - N Ammonia Nitrogen o2 Oxygen ORP Oxidation Reduction Potential R2 Coefficient of Determination (Square of Correlation Coefficient) SD Standard Deviation SSE Sum of Squares due to Error SSR . Sum of Squares due to Regression TKN Total Kjeldahl Nitrogen TOC Total Organic Carbon TS Total Solids TSS Total Suspended Solids VFA Volatile Fatty Acid xxii Acknowledgment I would like to express my sincere gratitude to my supervisor Prof. J.W. Atwater for his constant supervision, guidance and encouragement throughout this research. I would like to thank my supervisory committee, Drs. Donald S. Mavinic, Kenneth J. Hall and Sheldon Duff for their guidance and valuable comments and suggestions throughout this research. I also wish to thank Dr. Richard M.R. Branion for his valuable input on tracer studies. I am also grateful to Susan Harper, Paula Parkinson, Jufang Zhou and Guy Kirsch for their assistance during the setting up the experiment and analytical work. Also thanks are due to Martin Donat, John Brereton, Heather Artherton, Rhiannon Johnson and Ron Macdonald for their help in collection and filling up the refuse in the columns; to the residents of UBC student family housing who helped me in collection of food waste; Vancouver Transfer Station at Kent Avenue and Lions Gate Sewage Treatment Plant staff for their support. I am also grateful to all my family, friends and Sarah Dench for their support and encouragement. No words of gratitude could repay the moral support, encouragement and sacrifice by my husband Kamal. I would like to dedicate this work to my little girl Dinushi and to Kamal. "Dinushi, now that my thesis is finished, can I join your Earthsavers Club?" xxiii Chapter 1 Introduction Sanitary landfills have been a traditional means of solid waste disposal in most parts of the world including North America. Today, the environmental impacts of landfilling are well recognized and at most sanitary landfills, measures are taken to control these. In terms of early planning and designing of sanitary landfills, leachate treatment plants and gas disposal/treatment facilities, characterization of leachate and gas has become an absolute necessity. The characterization of landfill leachate is difficult for a number of reasons, the most important of which is the site specific nature of the leaching process. The climate, surface hydrology and hydrogeology of the site, all have a large influence on the amount of water entering and leaving a landfill. The amount of water along with the age, mode of site operation and the type of waste disposed of affect the nature and strength of the leachate produced. Also the moisture content of the waste, seasonal variations in infiltration, landfill microbiology, waste compaction, and use and composition of cover material have an influence on the characteristics of the resultant leachate (Robinson et al., 1982). Field studies done on leachate characterization show a relationship of water input patterns and hydraulics of the landfill to leachate strength and mass loading with respect to organic compounds. In the Port Mann landfill, Vancouver, B.C. and the Premier landfill, North Vancouver, B.C., peak organic concentrations coincided with the end of the peak rainfall period and the peak in the calculated leachate discharge flow rate (Jasper 1 Chapter 1. Introduction 2 et al., 1987). Similarly, at the Richmond landfill, Soper and McAlpine (1977) reported peak concentrations occurring with high water inputs. The same trend of peak organic concentrations during high leachate flows is also reported by other researchers (Bull et al. 1983, Rovers and Farquhar, 1973). As a response to new regulations, new landfills are designed to minimize the envi ronmental impact. Leachate production is minimized by controlling the water inflow into the landfill leaving a moisture deficient environment for biodegradation. This will extend the landfill stabilization period. Harris et al. (1994) calculated under these con ditions it will take 500 years or more for the landfills in U.K. to stabilize and leachate NH3 — N levels to reduce to dischargeable concentrations. Therefore if environmental impact from these landfills is to be minimized, liners, leachate and gas collection systems and treatment plants should be designed for over 500 years. More researchers; e.g. Harris et al. (1994) and Wall and Zeiss (1995) are recognizing the importance of introducing water into the landfills. But the observations of the researchers Jasper et al. (1987), Soper and McAlpine (1977), Rovers and Farquhar (1972) and Bull et al. (1983) show a limit in introducing water. Therefore before designing new landfills with moisture inputs, the coincidence of high organic carbon in leachate with water inputs should be properly understood. The objective of this thesis was to determine the effects of hydraulic retention time on landfill leachate and gas characteristics. Past literature (Jasper et al., 1987) suggests that there exists an interrelated effect of hydraulic retention time, rate of infiltration and moisture content on leachate and gas characteristics. To reduce the environmental impact from landfills and to satisfy the legislation requirements concerning aqueous dis charges into surface waters, treatment of leachate has become necessary. Coincidence of peak flow rates with peak concentrations greatly increase the mass loadings of pollutants to the treatment plants which will interfere with the treatment performances. Therefore Chapter 1. Introduction 3 the problem of increasing organic concentrations with increased flow should be addressed before designing landfills and/or treatment plants. Improved knowledge of the charac teristics of the leachate and gas with respect to the parameters; hydraulic retention time, infiltration rate and moisture content will help the designers of landfills and leachate treatment plants. Landfill management can be effectively done if the control parame ters can be manipulated to achieve the objectives such as maximizing gas production, maximizing landfill stabilization, minimizing landfill life etc.. The literature review (Chapter 2) summarizes background for the study and the parameters that affect landfill leachate and gas characteristics. The objectives of this study are given in Chapter 3. Materials and methods are described in Chapter 4. Results of the study and the discussion of results are presented in Chapter 5. Conclusions and the recommendations for the future work are given in Chapter 6. Chapter 2 Background and Literature Review 2.1 Introduction This research focuses on the effects of Hydraulic Retention Time (HRT) on characteristics of landfill gas and leachate. Reviewed in this chapter is the background for the research. Production of landfill leachate and gas is reviewed. Literature dealing with the factors affecting landfill leachate and gas characteristics is presented. The main factor affecting leachate and gas characteristics is decomposition of refuse. A review of biological pro cesses involved in decomposition of refuse and the factors affecting these processes are also presented. 2.2 Landfill Characteristics Once refuse is deposited in the landfill, physical, chemical and biological processes will take place. As a result gaseous, dissolved and suspended compounds in the form of landfill gas and leachate are released. In most landfills, assuming that they receive some organic wastes, the microbial processes will dominate the stabilization of waste and hence govern the generation and composition of landfill gas and leachate. 2.3 Leachate Production Leachate is water that has percolated through emplaced refuse and, in doing so, has suspended and dissolved constituents. Thus leachate constituents are a reflection of 4 Chapter 2. Background and Literature Review 5 material in the waste. Refuse, when disposed to landfills receives moisture from different sources. Moisture at placement and precipitation are major contributors. With the input of water into the refuse mass, sorption occurs. Leachate starts to appear before the refuse reaches its field capacity (described in Section 2.3.2) and will increase in flow rate until the landfill reaches its field capacity. The volume of leachate produced depends on volume of water entering and leaving the landfill. 2.3.1 Hydrological Balance in Landfills Figure 2.1 adapted from Canziani and Cossu (1989) gives an overall summary of the components which make up the hydrological balance of a controlled landfill where; P = Precipitation J = Irrigation or leachate recirculation R = Surface runoff Re = Run-on from external areas ET = Actual evapotranspiration Pi = Net infiltration through the cover Pi = P + J + Re - R - ET ± AUS Us = Water content in soil Uw = Water content in waste S = Water added by sludge disposal b = Water production if > 0; Water consumption if < 0 caused by the biological degradation of organic matter Is = Water from surface water sources Iq = Ground water infiltration L = Total leachate production Chapter 2. Background and Literature Review 6 Figure 2.1: Schematic of the General Hydrological Balance in a Completed Sanitary Landfill with Leachate Drainage System (adapted from Canziani and Cossu, 1989) L = Pt + S + Is + IG ± AUW + b LR — L - Lj Li = Infiltration into aquifers LR = Leachate collected by drains From this it can be seen that only some of the components of the hydrological balance can be influenced. A good description of all the component parts in the hydrological balance (see Fig ure 2.1) and with details on how to estimate each component is given in Canziani and Cossu (1989). Modern landfill designs are aimed at controlling the amount of water entering the landfills so that the leachate produced is minimized. Also in most modern landfills efforts are taken to control ground water inflow as well as to contain the leachate within the landfill. These measures will decrease the landfill leachate volume decreasing the Chapter 2. Background and Literature Review 7 cost of disposal. But the long term effects on the environment from the landfill are not addressed (Munasinghe and Atwater, 1996). 2.3.2 Field Capacity The field capacity is defined as the moisture content above which continuous gravity drainage will occur. Water infiltrating through refuse will be sorbed by the waste until the field capacity is reached. Any additional water will infiltrate to the next layer of refuse. Studies have shown breakthrough of leachate before the refuse mass reaches field capacity (Zeiss and Major, 1993). Moisture content is either calculated on volume basis or weight basis (dry or wet). Moisture contents through out this thesis are calculated on weight basis unless specified. Water percolating through a landfill will be sorbed by the waste until the field capacity is reached. When the infiltration of water exceeds the field capacity movement of water through the waste will occur. Field capacity of refuse depends on many factors. Density, type of refuse (composi tion, whether processed or not etc.) and the stage of decomposition of the waste (age). Table 2.1 (adapted from Table 8, Holmes, 1980) presents the field capacities for different densities and for wastes of different ages. It can be seen from this table that field capacity (weight basis) decreases with increasing density for raw refuse. Also that field capacity decreases with time. 2.3.3 Moisture Flow Through the Refuse Hydrologic models similar to the model discussed above in Section 2.3.1 are useful in predicting volume of leachate produced over time. But when it comes to the designs of leachate collection, bottom liners etc. it is necessary to know the velocity and discharge rate of water through layers of refuse. Also hydraulics of the landfill and the collection system should be known before designing leachate collection and treatment systems. Chapter 2. Background and Literature Review 8 Density Field Capacity Type of Waste (wet basis) (% weight) (% volume) (kg/m3) (on a wet basis) (on a wet basis) Raw 282 101 29 Raw 523 75 39 Raw 624 59 37 Raw mixed with sludge after: a. 4 yrs 638 60 38 b. 10 yrs 814 49 40 c. 17 yrs 960 44 42 Table 2.1: Field Capacities for Unprocessed Refuse (adapted from Holmes, 1980) Several researchers have investigated and modeled the flow through the refuse. Deme-tracopoulos et al. (1986) and Korfiatis et al. (1984) modeled the flow through solid waste landfills assuming the flow is predominantly vertical. Horizontal flow due to inhomo-geneities of the landfill material was assumed to be a small fraction of the total flow. The theory of unsaturated flow through porous media was used to develop their model. They found the model to be very sensitive to changes of the physical properties of the porous medium, mostly the hydraulic conductivity. Schroeder et al. (1988) modeled (HELP) vertical moisture flow through compacted municipal waste layers to be Darcian drainage flow through a constant homogeneous medium with constant characteristics over time. Characteristics of the refuse change much more than a soil medium due to decomposition and leaching of the material. Khanbilvardi et al. (1995) developed the model Flow Investigation for Landfill Leachate (FILL). This model describes the leachate flow process in a landfill as a two-dimensional unsteady-state moisture flow. All these researchers assumed the landfill to be comparable to a porous medium with constant characteristics. Refuse is a porous medium with characteristics changing Chapter 2. Background and Literature Review 9 with time due to decomposition and leaching of material. Refuse sorbs moisture, a characteristic that none of the researchers (except HELP model) accounted for in their models. Korfiatis (1984) acknowledged the importance of sorptive characteristics of the refuse but this was not accounted for in his model. Zeiss and Major (1993) observed channeling and flow along wetting curves which produced irregular and more rapid breakthrough times and leakage rates of leachate. In these experiments an infiltration rate of 94.6 mm/hr was used. Channeling is the vertical flow of liquid through channels with cross sectional areas which are substantially less than the cross section of the top layer of waste where infiltration occurs. The constriction of flow into channels through the waste layers in landfills is predicted to significantly reduce breakthrough and flow time from infiltration into the top waste surface until discharge to the underlying drainage layer. Their findings result in lower field capacities and breakthrough times and higher unsaturated hydraulic conductivities and leachate discharge rates than obtained from models that assume homogeneous Darcian flow. Zeiss and Uguccioni's (1995) experiments confirmed that the channeled flow through municipal solid waste is a significant flow mechanism at low loading rates (0.017 mm/hr and 0.034 mm/hr) also, as less than 45 percent (maximum) of the cross-sectional area of the solid waste column conveys flow, even at steady state. Also, the cross-sectional area did not become significantly larger over time indicating that Darcian flow may not be the dominant flow mechanism even at steady-state conditions. However, they also observed Darcian flow through the solid waste, by virtue of measured capillary pressure in many areas of the waste column gradually decreasing over time. This was coupled with an observed increase in storage with time. These observations further questions the predictability of the above mentioned mod els. Zeiss and Major (1993) analyzed seven key variables used in HELP model and found Chapter 2. Background and Literature Review 10 them to be considerably different from the values used. For example hydraulic conduc tivity was found to be 104 to 105 times more than the default values used in HELP. Korfiatis's (1984) model was very sensitive to the changes in physical parameters such as hydraulic conductivity. Observations by Korfiatis et al. (1984) showed that moisture content continued to increase after drainage has started indicating that secondary sorption and capillary action redistribute moisture into the waste from the primary flow channels. There was no work found on flow through a landfill from a bioreactor concept. 2.4 Landfill Gas Production and Characteristics 2.4.1 Decomposition of Refuse Once the solid wastes are placed in landfills, aerobic biological activity immediately begins to degrade the organic waste fraction. This aerobic phase results in accelerated waste consolidation, high internal temperatures and produces large volumes of carbon dioxide gas and degraded residual organics. This aerobic phase lasts for a short period of time as an oxygen deficit builds up creating semi-anaerobic conditions; conditions in which facultative anaerobes can then begin to metabolize and grow. The dominant anaerobic phase begins shortly thereafter, with the development of an obligate anaerobic population. These anaerobic bacteria will metabolize the organic carbon to CO2 and CH4. Figure 2.2 shows the most important interactions between the relevant bacterial groups, substrates and intermediate products. The anaerobic processes involved are viewed by Christensen and Kjeldsen (1989) as consisting of three stages. During the first stage solid and dissolved organic compounds Chapter 2. Background and Literature Review 11 Solid organic matter Complex dissolved organic matter Hydrolysis Dissolved organic matter Sulphate (S04) Sulphate reducing Fatty acids + alcohols 1 < ' Hydrogen sulphide (HjS) Carbon dioxide (CO^) 1 x Hydrogen Acetate Methanogeriic\ jgcetophilicX^ ithanogenic lydrogenophilic' Methane (CHS Figure 2.2: Substrates and Major Bacterial Groups Involved in the Methane Generating Ecosystem (adapted from Christensen and Kjeldsen, 1989) Chapter 2. Background and Literature Review 12 are hydrolyzed and fermented by fermenters to primarily volatile fatty acids, alcohols, hy drogen and carbon dioxide. Refuse degradation is an example of solid state fermentation. Therefore hydrolysis is a very important process in any landfill environment since the solid organic waste must be solubilized before microbial degradation. In the second stage, an acetogenic group of bacteria converts the products from the first stage to acetic acid, hydrogen and carbon dioxide. In the final stage, methane is produced by methanogenic bacteria. This is done either by acetophiles which convert acetic acid to methane and carbon dioxide or by hydrogenophiles which convert hydrogen and carbon dioxide to methane. The conversion of acetic acid to methane is by far the most important part of the methane-forming process (Christensen and Kjeldsen, 1989). 2.5 Factors Affecting Waste Decomposition Methane-forming ecosystems are exposed to a variety of highly variable factors in the landfill waste. The heterogeneity of the landfilled waste can make the landfill a highly diverse, but rather inefficient ecosystem. Figure 2.3 illustrates the major abiotic factors affecting the methane formation in the landfill: oxygen, hydrogen, pH, alkalinity, sul fate, nutrients, inhibitors, temperature and moisture content (Christensen and Kjeldsen, 1989). Other factors that affect waste decomposition and hence gas and leachate char acteristics are: refuse composition, emplacement and particle size, the hydrogeology of landfill area, the landfill age and the gas recovery system. 2.5.1 Oxygen The methanogenic bacteria are the most sensitive to oxygen and require a very low redox potential. Oxygen will either diffuse from the atmosphere into the landfill waste or will be carried with the infiltrating water. However, aerobic bacteria in the top layer of the Chapter 2. Background and Literature Review 13 Moisture Oxygen Temperature ; Inhibitors Methane generating ecosystem Hydrogen pH and Alkalinity Sulphate Nutrients Figure 2.3: Major Abiotic Factors Affecting the Methane-generating Ecosystem (adapted from Christensen and Kjeldsen) landfill waste will readily consume the oxygen and limit the aerobic zone to less than 1 m of compacted waste (Christensen and Kjeldsen, 1989). Gas recovery pumping may create a vacuum in the landfill, which would force the atmospheric air into the landfill. This may extend the aerobic zone in the waste and if gas recovery pumping is over done, formation of methane in these layers would be stalled. Zehnder (1978) reported that there were no spore-forming methanogenic bacteria. But methanogenic organisms are apparently resistant to the introduction of oxygen. Anaerobic incubation of aerobic sewage and aerobic soil fairly rapidly results in methane production (Zehnder, 1978). The existence of anaerobic microenvironments in the overall aerobic environment may be one explanation for the survival of the methanogenic bacteria in aerobic environments (Christensen and Kjeldsen, 1989). Chapter 2. Background and Literature Review 14 2.5.2 Hydrogen According to Mclnerney and Bryant (1983), the fermentative bacteria generate hydrogen, carbon dioxide and acetic acid at low hydrogen partial pressures, while hydrogen, carbon dioxide, ethanol, butyric acid and propionic acid are generated at higher hydrogen partial pressures. Ethanol, butyric acid and propionic acid may be further utilized by acetogenic bacteria, if the hydrogen partial pressure is not too high. The conversion of propionic acid requires hydrogen pressures below 9xl0~5 atmospheres (Christensen and Kjeldesen, 1989). Therefore if the hydrogen partial pressure is high, propionic and butyric acids will be generated but will not be further converted. Hydrogen can be consumed by methanogenic and sulfate-reducing bacteria. Hydro gen partial pressures of below 1CT5 atmospheres favor the formation of methane from hydrogen and carbon dioxide. If the hydrogen-consuming bacteria decrease their activi ties, hydrogen partial pressures will be increased. This would result in the accumulation of volatile fatty acids. 2.5.3 pH and Alkalinity Optimal pH values found in anaerobic digestion range from 6.4 to 7.4 with digestor performance collapsing at a pH of below 6.0 (Kotze et al., 1969). However, because of microenvironments and bacterial adaptability, methane production can occur at a pH less than 6.0. After refuse emplacement, there is generally, a gradual increase in pH to an optimal value. Chapter 2. Background and Literature Review 15 2.5.4 Sulfate According to Christensen and Kjeldsen (1989) sulfate reducing bacteria can interfere with methanogenic activity in landfills. This group of bacteria in many ways resem bles the methanogenic group. They are obligate anaerobes and can utilize hydrogen, acetic acid and higher volatile fatty acids during sulfate reduction. Several laboratory experiments done by Oremland and Polcin (1982) showed retardation of methanogene sis for the substrates hydrogen and acetic acid, when sulfate ion is present. Addition of other substrates (e.g. trimethylamine, methanol, or methionine) caused extensive en hancement of methanogenesis, regardless of the addition of sulfate. These results showed that suppression of methane formation by sulfate is not related to any toxic effects of sulfate on methanogenic bacteria but due to simple substrate competition. For pure cultures of methanogenic bacteria, sulfate does not suppress methane formation. If a sulfate-reducing strain is present, in mixed cultures (e.g. Desulfovibrio), suppression is substantial due to the higher energy yielded by sulfate reduction (Zehnder et al., 1978). Sulfate is a major compound in many waste types (e.g. demolition waste, incinerator slag, fly ashes) that are disposed of in landfills. Therefore, highly active sulfate reducers may decrease the amount of organics available for methane production. 2.5.5 Nutrients The anaerobic ecosystem must have access to all required nutrients, in particular nitrogen and phosphorus. All the necessary micronutrients, (e.g. sulfur, calcium, magnesium, potassium, iron, zinc, copper, cobalt, molybdanate and selenium) are considered to be present in most landfills (Christensen and Kjeldsen, 1989). The anaerobic ecosystem assimilates only a very small part of the substrate into new cells and therefore requires much less nitrogen and phosphorus than aerobic systems. In general, the mixed waste Chapter 2. Background and Literature Review 16 landfill will not be nitrogen or phosphorus limited but insufficient homogenization of the waste may result in nutrient-limited environments. 2.5.6 Inhibitors The methane-forming ecosystem is sensitive to inhibitors. The inhibitory effects of oxy gen, hydrogen and sulfate have already been discussed. The inhibitory effects of volatile fatty acids have been investigated and results presented in several references (McCarty and McKinney, 1961a; Kugelman and Chin, 1971). Inhibitory effects were not observed by Kugelman and Chin (1971) at a total concentration of acetic, propionic and butyric acids of up to 6000 mg/L. Carbon dioxide is produced in many of the degradation processes and its potential inhibitory effects have been investigated in sludge-fed batch reactors by Hansson and Molin (Hansson, 1979; Hansson, 1982; Hansson and Molin, 1981a,b). The removal rate of acetic acid was significantly affected by the increase of carbon dioxide partial pressure, while butyric acid removal, which does not produce carbon dioxide, was not affected. The partial pressure of carbon dioxide in a landfill may in the initial phases increase up to 0.9 atmospheres and will decrease to about 0.5 atmospheres. The mechanisms by which carbon dioxide inhibits methanogenesis are not yet known, although it has been speculated (Hansson, 1982) that the inhibition may be due to the raising of the redox potential. A second possibility is that carbon dioxide dissolves in the cell membranes of methanogens and impairs membrane function by increasing its fluidity (Senior and Kasali, 1990). MaCarty and McKinney (1961b) cited inhibition levels and stimulating levels of sodium, potassium, calcium, magnesium and ammonium (total). The inhibitory effects of ammonium are caused by free ammonia and hence are increasing with increasing pH. In landfill environments, the concentrations of the five cations are usually below the Chapter 2. Background and Literature Review 17 Compound Toxic Concentration, mg/L Reference Copper 150-250 500 1000 Rudgel, 1941 Rudgel, 1946 Barnes and Braidech, 1942 Nickel 200 1000 Barnes and Braidech, 1942 Wischmeyer and Chapman, 1947 Zinc 1000 350 Rudolphs and Zeller, 1932 McDermott and Barth, 1963 Nickel 2000 200 Barnes and Braidech, 1942 Pagano et al., 1950 Table 2.2: Reported Values of Toxic Concentrations of Heavy Metals in Anaerobic Waste Treatment (adapted from Kugelman and Chin, 1971) inhibitory levels. Heavy metals concentrations at which toxicity occurs in anaerobic waste treatment systems are given in Table 2.2 (Kugelman and Chin, 1971). These are much higher than the concentrations reported for aerobic treatments. According to Kugelman and Chin, (1971) these higher tolerance levels and variability are probably due to the fact that the heavy metals take part in complex-type reactions with the normal constituents of an anaerobic waste treatment unit. 2.5.7 Temperature The anaerobic waste degradation rate is highly affected by temperature. In laboratory simulations of landfill processes, the methane production rate has been proven to in crease significantly (up to 100 times), when the temperature is raised from 20 to 30 and 40 °C (Buivid, 1980; Ehrig, 1984). In a deep landfill the flux of heat from the landfill to the surroundings is small due Chapter 2. Background and Literature Review 18 to the insulating capacities of the waste, and the heat generated by the anaerobic de composition process may cause a temperature rise in the landfill (Rees, 1980b). Landfill temperatures of 30 - 45 °C should be possible even in temperate climates. 2.5.8 Moisture/Water Content Studies done on the effect of moisture content show increased methane production with increasing moisture content indicating increased stabilization of refuse. Despite the num ber of studies made, the question of the percentage moisture content required to facilitate increased stabilization is still a subject for debate. For example, de Walle et al. (1978) de termined in laboratory studies that water saturated refuse (99%, as dry weight) resulted in maximum rates as did Klink and Ham (1982). Similarly, Rees (1981) incubated refuse core samples under anoxic conditions at in situ temperature and showed that the highest rate (300 ml/kg dry weight per day) was apparent in material sampled from below the site water table. Farquhar and Rovers (1973) demonstrated maximum gas production at moisture contents between 60 and 80% wet weight. Similarly, de Walle et al. (1978) recorded maximum methane concentrations in the presence of a refuse moisture content of 78% and recommended that landfills which were to be used for gas production should be maintained at a moisture content in excess of 75% but below 100%. Leckie et al. (1979) studied whether the stabilization of refuse in a sanitary landfill can be accelerated by the controlled application of moisture with a resulting reduction in the time during which the landfill presents a potential source of pollution. This study showed the test cells with initial moisture content at field capacity showed higher stabilization (higher methane concentration and low organics in leachate) than the control which did not get additional moisture after placement. Cells with recirculation 1000 gal/day (3.8 m3/day, 17 mm/day) and continuous water addition 700 gal/day (2.7 m3/day, 12 mm/day) showed higher stabilization than others indicating higher methanogenic activity (high Ci74 %). Chapter 2. Background and Literature Review 19 From Kasali's (1986) results it was apparent that when the moisture content was raised above 60%, gas production started to decline, thus suggesting that this discrete moisture regime satisfied the physiological requirements of the methanogenic organisms. Since, moisture promotes the mass transfer or the distribution of other methanogenic enhancement precursors (Buivid et al., 1981), it may be speculated that once such dis tributions were optimized, then elevated moisture contents, approaching field capacity, would be of little value since both gas and methane evolution rates would be independent of the moisture regime (Senior and Kassali, 1990). In addition, it is possible that large water additions may also introduce oxygen, thus delaying initiation of methanogenesis, and may also stimulate acidogenesis to the detriment of the initially low and slow-growing methanogenic population (Rees, 1980a). These two possibilities offer a partial explana tion for the lower volume of methane generated at a moisture content of 80% versus 60%. Similar results were reported by Buivid et al. (1981). They also found a substantial decrease in methane production when the moisture content of the municipal solid waste was increased above 80%. Senior and Kasali (1990) speculated that total waterlogging, particularly during the initial stages of refuse emplacement, could be inhibitory, such that flooded sites or fills extending below the water table may not provide the optimum conditions for methane generation. Moisture flow through solid wastes is discussed in Section 2.3.3. Moisture in the refuse could be distributed unevenly due to channeling observed by Zeiss and Major (1993) and Zeiss and Uguccioni (1995). Therefore biodegradation rates could be different from place to place depending on the availability and movement of moisture. Zeiss and Uguccioni (1995) indicate that zones of intense nutrient transport and waste removal may occur around channels resulting in higher biodegradation rates in these areas. Biodegradation in other areas will still occur at a slower rate, as nutrients and wastes are transported and removed by uniform moisture fronts flowing through the solid waste matrix. Chapter 2. Background and Literature Review 20 2.6 Landfill Leachate Characteristics Landfill leachate strength varies considerably from landfill to landfill because of the wide range of site specific conditions; e.g., moisture content of the refuse, seasonal variations in infiltration through the refuse, composition of wastes, landfill microbiology, depth of the landfill, compacted density, use and composition of cover etc.. Table 2.3 obtained from the published literature shows typical leachate constituent concentrations for land fills. In this table Robinson et al. (1982) data were taken from analysis of 23 samples of leachate from 15 sites in the UK. Their observations showed that leachates from re cently emplaced refuse contained high concentrations of dissolved organic substances, a large portion of which were short chain fatty acids. In sites where refuse has been em-placed for longer periods, the BOD, COD and TOC in the leachate were lower. Also the ratios BOD/COD and BOD/TOC were lower indicating the smaller proportions of biodegradable compounds from aged wastes. Characteristics of leachate reported (Jones et al, 1985) from municipal solid waste lysimeters are presented in Table 2.3. These ranges of concentrations were extracted from the tables of the document (Jones et al., 1985) for the columns containing municipal solid wastes only. In their study, leachate was characterized over a period of 4 years for three lysimeters receiving a precipitation of 12.7 mm/week. Higher concentrations represent the initial leachate for all parameters except for pH. 2.7 Change in Landfill Gas and Leachate Characteristics with Time Christensen and Kjeldsen, (1989) speculate on a theoretical or idealized sequence of the involved degradation processes and their consequences as to gas and leachate composition involving five distinct decomposition stages (Decomposition stages I-V) (Figure 2.4). This is based on Farquhar and Rovers (1973) and Ehrig (1984). Barlaz et al. (1989) updated Chapter 2. Background and Literature Review 21 Concentrations Concentrations Compound for landfills for lysimeter studies Robinson et al. (1982) Jasper et al. (1987) Jones et al., (1985) pH* 6.2 - 7.4 6.26 - 7.37 4.35-6.2 COD 66 - 11600 232 - 2240 5890-44800 BOD <2 - 8000 10.7 - 1230 1020-33000 TOC 21 - 4400 60 - 565 1900-24500 Ammonia-N 5 - 730 51.9 - 236 — Chloride 70 - 2777 93.9 - 498 70-1442 Na 43 - 2500 94.7 - 463 12-1225 Fe 0.09 - 380 24.5 - 127 229-1110 Zn <0.05-0.95 0.113 - 2.91 0.14-32.5 TKN — 64 - 277 78-1380 Alkalinity — 19.9 - 46.0** 184-8000 VFA — <25 - 1028 Conductance + — 2238 - 5751 2200-11000 Table 2.3: Typical Leachate Constituent Concentrations for Landfills (all Concentrations in mg/L except *-pH units, **-meq and + -/imhos/cm) the characterization of refuse decomposition including data on microbial population de velopment and chemical constituents during decomposition. Their characterization study consisted of leachate recycle with neutralization in laboratory scale landfills. Summary of their characterization is given in Figure 2.5. Characteristics of the Decomposition stages I and II in Figure 2.4 and aerobic and anaerobic acid in Figure 2.5 are similar. Decomposition stages III, IV and V in Figure 2.4 were characterized in Barlaz et al. (1989) (Figure 2.5) in two stages; accelerated methane and decelerated methane phases. Christensen and Kjeldsen (1989) described the decomposition stages as follows; Decomposition stage I: A short aerobic stage immediately after landfilling the waste, where easily degradable organic matter (soluble sugars) is aerobically decomposed and carbon dioxide is generated. During this period, depletion of OQ, and increasing CO2 concentration will occur in the landfill environment. In Barlaz et al. (1989) study only Chapter 2. Background and Literature Review 22 2% of the soluble sugars were oxidized during this period. Decomposition stage II: Immediately after the aerobic decomposition stage the first intermediate anaerobic stage develops. The activity of the fermentative and the acidogenic bacteria results in a rapid generation of volatile fatty acids, carbon dioxide and hydrogen. The acidic leachate may contain high concentrations of fatty acids, cal cium, iron, heavy metal and ammonia. The latter due to hydrolysis and fermentation of proteineous compounds in particular. The concentration of nitrogen in the gas is reduced due to the generation of carbon dioxide and hydrogen. The initial high concentration of sulfate may slowly be reduced as the redox potential drops. The generated sulfide may precipitate iron, manganese and heavy metals that were dissolved in the initial part of this stage. According to Barlaz et al. (1989), pH decrease and accumulation of VFAs are due to insufficient levels of oxygen and nitrate in fresh refuse for the complete oxidation of sugars, COi dissolution and low acid-consuming activities of the acetogenic and methanogenic bacteria. Their data showed that cellulose and hemicellulose hydrolysis was not consistent during this phase. They suggested that the feedback inhibition of polymer hydrolysis by the accumulated carboxylic acid and any cellulose and hemicellulose hydrolysis which occurred must have aggravated the acid accumulation. Decomposition stage III: A second intermediate anaerobic stage will start with slow growth of methanogenic bacteria. The methane concentration in the gas increases, while hydrogen, carbon dioxide and volatile fatty acid concentrations decrease. Also the sulfate concentration decreases due to continued sulfate reduction. The conversion of fatty acids results in a pH and alkalinity increase which results in a decreasing solubility of calcium, iron and manganese and heavy metals. The latter are supposedly precipi tated as sulfides. Ammonia is still being released and is not converted in the anaerobic environment. Chapter 2. Background and Literature Review 23 Decomposition stage IV: The methane stage is characterized by a fairly stable methane production rate resulting in a methane concentration in the gas of 50% - 65% by volume. The high rate of methane formation maintains the low concentrations of volatile fatty acids and hydrogen. Decomposition stage V: Where only the more refractory organic carbon remains in the landfilled waste, the methane production rate will be so low that nitrogen will start appearing in the landfill gas again due to diffusion from the atmosphere. Aerobic zones and zones with redox potentials too high for methane formation will appear in the upper layers of the landfill. During accelerated methane phase Barlaz et al. (1989) measured an increase in methanogenic (cellulolytic and acetogen) populations. There was little solids hydrolysis and suggested feedback inhibition due to the acid accumulation. This phase showed the maximum methane production. During decelerated methane phase (Barlaz et al., 1989) maximum rate of solids de composition was observed. At the end of this phase only 28% of cellulose plus hemicel-lulose present in fresh refuse were remaining as opposed to 63% at the end of accelerated methane phase. Continuous decrease in methane production was observed and suggested that there was a decrease in polymer hydrolysis. The above mentioned behavior of landfill gas and leachate could be seen in landfill simulators if their volume of waste is homogeneous. In real landfills the conditions are far from these. In landfills with or without cells, there is a highly varying composition and age of refuse. This could produce a completely different landfill and leachate behavior than the above presented. This can be seen from the extent of variation and ranges of the constituents presented in Table 2.3. Chapter 2. Background and Literature Review 24 Gas composition, vol % 100 1 , i Leachate Leachate Figure 2.4: Illustration of Developments in Gas and Leachate Composition in a Landfill Cell (adapted from Christensen and Kjeldsen, 1989) Chapter 2. Background and Literature Review 25 Figure 2.5: Summary of Observed Trends in Refuse Decomposition with Leachate Recycle (adapted from Barlaz et al, 1989) Chapter 2. Background and Literature Review 26 2.8 Effects of Infiltration of Water through Refuse Rovers and Farquhar (1973) concluded in their work that rapid infiltration impedes methane production. The distinction between moisture volume and infiltration rate was subsequently endorsed by Klink and Ham (1982) who demonstrated methanogenic rate increases between 25% and 50% in the presence of moisture movement and found that the relationship held even when the total moisture content was constant. From their studies it was concluded that moisture content and moisture movement are separate variables affecting landfill methanogenesis. A study by Leckie et al. (1979) described in Sec tion 2.5.8 showed recirculation and continuous water addition increases methanogenesis. Both these increased the infiltration. Recirculation provided higher infiltration rate (3.8 m3/day, 17 mm/day) than the continuous water addition (2.7 m3/day, 12 mm/day). The cell with leachate recycle showed higher stabilization. It may be speculated that higher infiltration had an additional effect to mixing of methane precursors. From studies by Leckie et al. (1979) and Rovers and Farquhar (1973) it can be seen that up to a certain level increasing infiltration increases methanogenesis but there exists a break point infil tration rate after which methanogenesis fails. Field studies done by Wreford (1995) at Vancouver Landfill site at Burns Bog, located in Delta, British Columbia, indicated that the most significant factor affecting CR\ production was the cumulative precipitation 14 days prior to sampling. In all the cases observed by this study the periods of high moisture input coincided with peak CH4 production. 2.9 Effects of Rainfall Pattern on Landfill Leachate and Gas Characteristics Field studies done on leachate gas characterization show a relationship of water input patterns and hydraulics of the landfill site to leachate strength and mass loading with respect to organic compounds. In Port Mann landfill, Surrey, B.C. and Premier landfill, Chapter 2. Background and Literature Review 27 North Vancouver, B.C. peak organic concentrations coincided with the end of the peak rainfall period and the peak in the calculated leachate discharge flow rate (Jasper et al., 1987). Similarly, at the Richmond landfill, Soper and McAlpine (1977) reported peak concentrations occurring with high water inputs. The same trend of peak organic concentrations during high leachate flows is reported by Bull et al. (1983). Similar observations are reported by Rovers and Farquhar (1973) in their study of refuse placed in a 11.3 m3 (400 cubic feet) cylindrical cell. After 115 days CH4 concentrations of 19% (by volume) were established in their refuse columns. At that point, large amounts of water generated from melting snow and ice infiltrated the refuse causing a large increase in leachate production. The infiltration coincided with a reduction in CH4 gas concentration to 4% (by volume) with an increase in COD, BOD and volatile dissolved solids and a decrease in alkalinity and pH in the resulting leachate. Characteristics of these landfills and lysimeters are given in Table 2.4. Port Mann landfill leachate is characterized by low concentration of BOD and COD, neutral pH, low level of metals, high NHz — N and moderate total salt concentrations, with little day-to-day variations and large overall trends for organic constituents (Jasper et al, 1987). If this leachate pattern observed (mentioned earlier) is due to either or all of (1) as more water flows into, more refuse is brought up to field capacity, therefore contributing more of each constituent to the leachate, (2) due to the effect of water input on the pathways of water, and (3) due to high infiltration, additional pathways developed, it should be the trend for all the constituents. Instead, some constituents decrease, some stay constant, others increase with increasing water input. Landfills with long retention time have low organic carbon levels in leachate due to long enough retention time for methanogenesis and ones with short retention time have high organic carbon levels. When the conditions exists such that retention time shifts from long to short, then high organic carbon levels will appear in leachate, due to loss of methanogenesis. This hypothesis Chapter 2. Background and Literature Review 28 Landfill Location Average annual rainfall (mm) Average depth during the study (m) Type of waste dispo-sited Age of the waste Estimated HRT (day) Port Mann Surrey, British Columbia, Canada 2075 10 MSW and commercial 8 yrs 6 - 600 Premier North Vancouver, British Columbia, Canada 2500 20 - 30 MSW and commercial 2 - 3 yrs storm response about 7 days Richmond Richmond, British Columbia, Canada 1000 6 MSW, commercial and industrial 5 yrs 4 - 1000 Table 2.4: Characteristics of Landfills with High Organic Carbon during High Water Input explains the trends in Port Mann landfill as the shortest retention time corresponds to the peak concentration in organic carbon in leachate (Jasper et al., 1987). Rovers and Farquhar (1973) concluded in their work that rapid infiltration impedes methane production. Rapid infiltration decreases retention time. Recirculation of leachate in landfills improves the stabilization process. According to Pohland et al. (1980) this increased methane formation compared to a normal landfill (without recirculation) is due to the benefits of distributing methane formers and nutrients throughout the landfill mass. Recirculation of leachate increases retention time of water in the landfill. It is suggested that there is an effect from increased retention time, in addition to the benefits Chapter 2. Background and Literature Review 29 discussed by Pohland et al. (1980). These results show that there exists an interrelated effect of hydraulic retention time, rate of infiltration and moisture content on leachate and gas characteristics. To reduce the environmental impact from landfills and to satisfy the legislation requirements con cerning aqueous discharges into surface waters, treatment of leachate has become neces sary. Coincidence of peak flow rates with peak concentrations, greatly increase the mass loadings of pollutants to the treatment plants which will interfere with the treatment performances. Therefore the problem of increasing organic concentrations with increased flow should be investigated and addressed before designing landfills and/or treatment plants. If the landfill hydraulic regime determines the decomposition stage of the landfill as explained earlier, it should be possible to adjust organic carbon levels in leachate by manipulating landfill hydraulics. Retention time can be changed by controlling the leachate removal or recirculation of the leachate to the top of the landfill. This is useful for existing landfills that have high seasonal organic carbon peaks of short duration. In designing new landfills, flexibility to change hydraulics can be incorporated, so that peaks can be damped out by manipulating landfill hydraulics. Therefore work should be done to understand the behavior of landfills under different retention times and varying retention times. Trends observed in other constituents also should be explained to confirm the above mentioned hypothesis. Also improved knowledge of the characteristics of the leachate and gas with respect to the parameters; hydraulic retention time, infiltration rate and moisture content will help the designers of landfills and leachate treatment plants. Landfill management can be effectively done if the control parameters can be manipulated to achieve the objectives such as maximizing gas production, maximizing landfill stabilization, minimizing landfill life etc.. Chapter 2. Background and Literature Review 30 2.10 Landfill Stabilization A landfill is considered stabilized when the maximum settlement has occurred, negligible gas production is occurring and leachate does not constitute a pollution hazard. When refuse is placed in landfills, stabilization will take place as a result of physical, chemical and biological processes. In most landfills biological processes will dominate the stabiliza tion of the waste. Microbial processes in the landfills and the factors affecting them are discussed in Sections 2.4 to 2.9. Stabilization of refuse can be accelerated by enhancing the microbial processes. Barlaz and Ham (1990) reviewed the effects of enhancement variables; moisture content, leachate recycle and moisture flow, particle size, innoculum addition, pH, nutrient addition and temperature addition. Stegman and Spendlin (1989) reported placing a thin layer of uncompacted, composted refuse improved methanogenesis by decreasing souring. Once the refuse is deposited in landfills, the degradable portion will be eventually degraded. The time taken to degrade the refuse will depend on the availability of factors that affect the degradation processes. Enhancing biodegradtion processes will shorten the time to stabilize the landfill while releasing gas and leachate during gas and leachate collection facilities are in good condition. Present landfill cover and liner requirements do not recognize this as it reduces the input of moisture, an important parameter for degradation. 2.11 Hydraulic Retention Time of Landfills Moisture flow through the refuse was discussed in the Section 2.3.3. Also the models developed to analyze the flow through refuse were briefly discussed. There was no work done on flow characteristics of landfills considering it as a bioreactor. Flow characteristics of other bioreactors such as anaerobic digestors, anaerobic filters have been analyzed and Chapter 2. Background and Literature Review 31 established. For an ideal plug flow reactor HRT is defined as; HRT = ^ (2.1) Where; V= Volume of the reactor (L3) Q= Flow rate through the reactor (L3T_1) Flow through a plug flow reactor does not follow this idealized flow pattern even in chemical reactors. But according to Levenspiel (1972) a large number of designs approximate the ideal plug flow with negligible error. In other cases deviation from the ideal can be considerable. These deviations can be caused by channeling of fluid, by recycling of fluid, or by creation of stagnant regions in the reactor. When it comes to the estimation of HRT for wastewater reactors assuming plug flow conditions, deviations from the ideal can be significant. Though HRT calculated assuming a plug flow is used as a control parameter in wastewater treatment plants. When it comes to landfill reactors, the contents and the volume of the reactor both are very difficult to estimate. Therefore the flow patterns could be far from plug flow. This could be the reason for the efforts by different researchers to estimate the time taken to travel (residence time) through the landfill by other means (discussed in Section 2.3.3). For nonideal flow Levenspiel (1972) defined the term mean residence time (holding time, space time) for the HRT calculated from the Equation 2.1. Residence time of water in landfills is very difficult to predict. It is dependent on many factors such as leachate collection system (whether it provides free drainage or not), depth of landfill and again on saturated and unsaturated depths, compaction of Chapter 2. Background and Literature Review 32 Tracer Tracer input N. -*" 0 0UtPut signal Ves^S c^/r s'8nal (stimulus) (response) Time Time Figure 2.6: Stimulus-Response Techniques Commonly used to Study Flow in Reactors (adapted from Levenspiel, 1972 ) refuse etc.. Residence time in landfills can be changed due to many causes. Change in depth of refuse and rate of infiltration changes retention time. With increasing rainfall if the depth of saturated layer increases, retention time is increased. There is a need to investigate the term HRT as applicable to landfills. Experimental methods are used to characterize the extent of nonideal flow by means of exit age distribution function (Levenspiel, 1972). To accomplish this, the system is disturbed and then its response to this disturbance is measured. An analysis of the response gives the desired information about the system. In most of the cases the stimulus is a tracer input into the reactor, whereas the response is a time record of the tracer leaving the reactor. Any material that can be detected and which does not disturb the flow pattern in the reactor can be used as tracer, and any type of input signal may be used; a random signal, a periodic signal, a step signal, or a pulse signal. These signals and their typical responses are shown in Figure 2.6. There are a variety of tracer inputs used in experiments; Fluorescin, NaCI, LiCl and Chapter 2. Background and Literature Review 33 Rhodamine B are some of them. Among all the tracers that are used LiCl is recommended when sorption of the tracer onto the reactor contents is a concern (Branion, 1992). For a pulse input the normalized tracer response curve is called the C curve. This C curve directly gives the exit age distribution. The mean of the exit age distribution curve gives the mean residence time. This gives a good estimation of the mean flow rate through the reactor. It is not practicable to use this technique in real landfills. But it can be used in pilot scale and lab scale landfill simulators which are used to develop models. It can then be extended to the real landfill to make predictions. 2.12 Present Trends in Landfill Management and Timing of the Research As a response to the past ground water problems and to new regulations, new landfills are Hesigned to minimize the environmental impacts. Leachate production is minimized by controlling the water inflow into the landfill using top and bottom liners. Leachate produced is collected using a drainage system and treated in in situ treatment plants before discharge into the natural water sources or discharged into sewers for treatment with domestic sewage. Gas produced is collected and used or flared reducing the impact from the landfill. This type of landfill design will keep the landfill under very low moisture conditions. Since the moisture is a principal factor for biodegradation, the dry vault design will extend the stabilization period of the landfill beyond that of a conventional landfill. Therefore landfills (liner systems, cover, gas and leachate collection systems etc.) should be designed for a longer life span. Otherwise the landfill will still be a threat to the environment discharging strong leachate and gas if the liner systems fail. An alternate approach was discussed by Wall and Zeiss (1995), to design and operate the landfill as an anaerobic digestor. This design consists of the bottom- and top-liner Chapter 2. Background and Literature Review 34 systems, but may include inputs of moisture. Therefore it is important to investigate the related topics such as moisture, infiltration and seasonal variations in rainfall to explore the opportunities to incorporate moisture from these methods. The importance of moisture in the landfill stabilization is well documented as discussed in Section 2.5.8. Effects of moisture movement and infiltration are discussed in Section 2.8. The effects of infiltration have not being explored enough to use infiltration as a means of introducing moisture into the landfills or as a means of increasing stabilization of landfills. Hydraulic retention time is a function of infiltration. Improved knowledge of effects of HRT and infiltration will be beneficial in landfill planning, designing and operations. 2.13 Summary Observations of past researchers (Soper and McAlpine, 1977; Jasper et al., 1987; Bull et al., 1983; Rovers and Farquhar, 1973) show that there exists an interrelated effect of hydraulic retention time, rate of infiltration and moisture content on leachate and gas characteristics. To reduce the environmental impact from landfills and to satisfy the legislation requirements concerning aqueous discharges into surface waters, treatment of leachate has become necessary. Coincidence of peak flow rates with peak concentrations, greatly increase the mass loadings of pollutants to the treatment plants which will in terfere with the treatment performances. Therefore the problem of increasing organic concentrations with increased flow should be investigated and addressed before designing landfills and/or treatment plants. If the landfill hydraulic regime determines the decomposition stage of the landfill as explained earlier, it should be possible to adjust organic carbon levels in leachate by manipulating landfill hydraulics. Retention time can be changed by controlling the leachate removal or recirculation of the leachate to the top of the landfill. This is useful Chapter 2. Background and Literature Review 35 for existing landfills that have high seasonal organic carbon peaks of short duration. In designing new landfills, flexibility to change hydraulics can be incorporated, so that peaks can be damped out by manipulating landfill hydraulics. Therefore, work should be done to understand the behavior of landfills under different retention times and varying retention times. Also, improved knowledge of the characteristics of the leachate and gas with respect to the parameters; hydraulic retention time, infiltration rate and moisture content will help the designers of landfills and leachate treatment plants. Landfill management can be effectively done if the control parameters can be manipulated to achieve the objectives such as maximizing gas production, maximizing landfill stabilization and minimizing landfill life. Chapter 3 Objectives Observations of landfill leachate characteristics have shown a trend of increasing organic carbon with increasing rainfall or water input (Soper and McAlpine, 1977; Jasper et al., 1987; Bull et al., 1983; Rovers and Farquhar, 1973). The proposed hypothesis was that methanogenesis failure was due to the reduction in Hydraulic Retention Time (HRT) with increasing infiltration. Rovers and Farquhar (1973) concluded in their work that rapid infiltration impedes methanogenesis. In the study by Jasper et al., (1987), char acterization of gas was not done. Alternatively Leckie et al. (1979) observed increasing methanogenesis with increasing infiltration through the refuse although his infiltration rates were relatively low. Studies by Rovers and Farquhar (1973) and Leckie et al. (1979) showed that there exists a breakthrough infiltration after which methanogenesis fails. Coincidence of peak infiltration rates with increased organic carbon concentrations would greatly increase the pollutant loadings to the treatment plants which will interfere with the treatment plant performances. Therefore, it is necessary to understand this relationship to facilitate the design of landfills and treatment facilities for leachate. The objectives of this research were; 1. To study the effects of Hydraulic Retention Time (HRT) on landfill leachate and gas characteristics. 2. To explore the breakthrough infiltration rate for methanogenesis. 3. To propose possible explanations for the increasing organic loadings in landfill leachates. 36 Chapter 3. Objectives 37 To achieve these objectives, eighteen landfill simulators were constructed. To compare the effects due to different HRTs, other factors that affect leachate and gas characteristics were kept to a minimum. Since the refuse filled was fresh from houses there was concern regarding the time to establish methanogenesis. Therefore anaerobic digestor sludge was added as a seed to initiate methanogenesis. The experiments were conducted in four phases. The purpose of phase I was to investigate the reproducibility of all columns under identical independent variables. This phase lasted for 163 days. Phases II and III were done to demonstrate the effects of HRT on landfill leachate and gas characteristics. Leachate characterization studies discussed in Section 2.9 showed higher concentrations of organics coincide with high water inputs. The HRT was changed by changing infiltration rate. Different HRTs were established in each column and con firmed using tracer study. To study the variation of HRT with time (decomposition of refuse) a second tracer study was done for columns 7 and 10. There was no indication of failure of methanogenesis under the range of HRTs assigned during phase II. As the objective of exploring the breakthrough HRT (infiltration rate) for methanogenesis was not accomplished during phase II, the HRT was further lowered by increasing the infiltration rate (phase III). Columns 16 and 18 were assigned the HRTs of 6 and 3 days as a preliminary study to phase III. There was no indication of failure of methanogenesis but an enhancement was observed. Phase II and III lasted for 300 days and 60 days, respectively. HRTs of the remaining columns (except 7, 10, and 15) were reduced to 13 days to see whether there is an effect from the original HRT on the characteristics of leachate and gas when HRT is lowered. During phase IV gas was characterized for a further 90 days to see the effects of succession of infiltration through the columns. Chapter 4 Experimental Methods and Analytical Procedures Characteristics of gas and leachate are affected by many environmental parameters. This research was aimed at finding the effects of HRT on landfill leachate and gas character istics. Therefore, experiments were designed in a way to minimize effects from other parameters. The experiments were located in the laboratory to minimize temperature fluctuations throughout the research. Composition of the refuse filled was the same. Mixing and filling the refuse according to the composition was done in small batches to achieve a uniform composition in the columns. Eight batches were needed to fill one column. 4.1 Experimental Set-up 4.1.1 Construction of Lysimeters Eighteen lysimeters were constructed using 30 cm diameter by 180 cm high PVC pipes as shown in Figure 4.1. The flanges at the top and the cones at the bottom were fabricated using fiber glass. Flexible tubing of 12 mm diameter was fixed to the bottom. A loop in the tubing was used to prevent entry of air from the bottom. The bottom of the column (cone shaped part) was filled with 19 mm gravel with a layer of pea gravel on top. This was done to provide free drainage of leachate. A frame was constructed to position the 18 columns vertical. Columns were tested for water leaks by filling them with water. After the columns 38 Chapter 4. Experimental Methods and Analytical Procedures 39 water tank pump teed Vvdter to vent 40 cm compacted refuse 140 cm gas sampling port 29 cm diameter PVCpipe wet gas meter pea gravel Figure 4.1: Schematic of the Experimental Set-up Chapter 4. Experimental Methods and Analytical Procedures 40 Material Quantity Weight per batch (kg) % Paper 1.93 31.7 Plastic 0.35 5.7 Organics (food, garden waste etc.) 3.20 52.6 Metals 0.35 5.7 Glass 0.25 4.1 Total 6.08 100 Table 4.1: Composition of Refuse were prepared (Section 4.1.3) lids were placed and sealed carefully. Air tightness of the columns was very important since gas production rates were measured. Also air tight columns were necessary to measure the gas production rates since the functioning of the gas meters was dependent on it. All the gas meters showed build-up of the small pressure in the columns indicating airtight columns. 4.1.2 Filling of Refuse in the Columns Refuse was collected separately for each category shown in Table 4.1. This is the com position of refuse typical to the Greater Vancouver Area (Waste Program Consortium, 1992) and reflects the existence of an active recycling program (paper, plastic, metal and glass) at the residential level. Food Waste Food waste was collected from UBC family housing during April and May 1993. Residents separated their food waste from other refuse and put it into zip lock bags each day (this was done for their convenience) and stored in a garbage bag for weekly collection. After collection, the bags were emptied into big garbage bags and were stored at 4 °C until the columns were ready to be filled. Food waste was not shredded. Chapter 4. Experimental Methods and Analytical Procedures 41 Paper Shredded (2-4 cm) mixed paper was taken from a mobile shredding truck of Proshred Company Limited. Plastic Plastic was taken from the Vancouver Transfer Station at Kent Avenue. These were shredded to a size of approximately 2-4 cm by the mobile shredder of Proshred Company Limited. Metal Metals were brought from Vancouver Transfer Station at Kent Avenue and shredded to a size of 2 - 4 cm by the mobile shredder of Proshred Company Limited. Glass Glass was collected from my home and lab and broken into pieces of size 2-4 cm by tamping in a bucket. Yard Waste Yard waste was collected from Keremeos court, UBC family housing cleanups. This waste included leaves, dirt, weeds and soil. Another portion of yard waste included cut grass and was collected from the field near B.C. Research. Moisture content of the mixed waste was measured by drying the samples at 104 °C. This was done prior to filling the columns for a batch of garbage collected from home (same composition of materials). Chapter 4. Experimental Methods and Analytical Procedures 42 After collecting all the refuse, the columns were filled according to the composition in Table 4.1. Weights from each category as in Table 4.1 were measured and mixed in a concrete mixer. Eight batches were needed to fill a column. The batches were compacted to 120 cm height by tamping using a wooden block fixed to a steel rod. Columns were filled one at a time. Four kilograms of additional yard waste/cut grass was added to each column and compacted to 20 cm. All the columns were compacted to a height of 140 cm to achieve a density (wet weight basis) of 570 kg/m3. After measuring the moisture absorbed (discussed in Section 4.1.3) 10 liters of anaerobic digestor sludge from Lions gate sewage treatment plant was added as a seed. On the same day the columns were covered with plates which were fitted with plumbing for exit gas and inlet water. Drain tubes were closed to avoid loss of water. Other than the exit gas tube explained in the following paragraph all other joints were sealed to prevent air entry. Eighteen wet gas meters were placed in a platform, constructed near the columns and connected to each column. A schematic of a wet gas meter is shown in Figure 4.2. Since flexible tubing is permeable to gas, Cu tubing was used for plumbing. The exit gas tubes were connected to the wet gas meters. Calibration of each gas meter was done before connecting. Columns 16, 7, 18 and 1 were the first columns to be connected. The others except 10 and 13 were connected over a period of two weeks. Columns 13 and 10, because of mechanical problems, were connected about 6 weeks after the first group. Once a gas meter is connected to a column the column becomes completely sealed against air entry. Water was pumped to the lysimeters from a 40 liter capacity overhead tank. The tank was fed using a tube connected to a tap near the columns. For the infiltration a proportioning pump (Model Pump III from Pulse Instrumentation Ltd.) that can accommodate 26 channels (tubes) was installed and plumbing was done with flexible tygon tubing. Leachate was discharged to a drain unless samples were being collected. Chapter 4. Experimental Methods and Analytical Procedures 43 Gas exit Gas enter Sensor Counter Magnet Gas Collected Figure 4.2: Schematic of a Wet Gas Meter 4.1.3 Preparation of Columns for the Study After the experimental landfill columns were set-up, and filled with refuse, they were flooded with water and let stand for 4 days so that the refuse was well wetted. The saturating water was then drained and measured. A water balance was done to calcu late the amount of water absorbed. Moisture at placement was calculated from initial moisture content data. Characteristics of the prepared column and feed water are given in Table 4.2. 4.2 Selection of HRTs for the Study HRTs of the landfills where leachate organic carbon increased with increasing water input are given Table 2.4. Lower HRTs correspond to rainfall events during winter. These rain fall events last for shorter periods. Depth of the laboratory scale lysimeters used is much Chapter 4. Experimental Methods and Analytical Procedures 44 Condition/Characteristic Refuse weight at placement wet weight (kg) 52.64 Refuse height at placement (cm) 140 Refuse compacted density (kg/m3) 570 Moisture content at placement (% wet weight basis) 36 Temperature of feed water (°C) 15 - 18.8 Alkalinity of feed water (mg/L as CaCOz) 1.1 - 1.5 Hardness of feed water (mg/L as CaCOz) 3.10 - 3.93 pH 5.9 - 6.0 Temperature of the laboratory where the columns were kept (°C) 15 - 27 Table 4.2: Characteristics of the Prepared Columns and Feed Water smaller than the real landfills. Achieving higher HRTs will need the addition of small volumes of water at spaced intervals. For lower HRTs high volumes are needed at shorter intervals. It was not practical to use different time intervals for different columns. Also it would create different unpredictable hydraulic conditions in each column. Therefore it was decided to manipulate the HRTs using continuous application of water. The main source of infiltrating water for landfills is precipitation. Precipitation on landfills varies from landfill to landfill with time. Annual precipitation in Vancouver, B.C. landfills are in the range of 1000 mm to 2350 mm. This is not distributed evenly throughout the year. For example Vancouver receives most of its rainfall from September to May. June, July and August are considered dry months. Therefore 1000 mm to 2350 mm precipitation will be often distributed over nine months, instead of twelve months. Port Mann landfill, Vancouver discussed in Section 2.9 does not have any surface runoff during rainfall events. Therefore all of its 2350 mm of rain infiltrates through the refuse creating lower hydraulic retention times. Rainfall in other parts of the world with monsoon rain creates even lower HRTs. For Chapter 4. Experimental Methods and Analytical Procedures 45 example Sri Lanka's annual rainfalls for the years 1990 and 1991 ranged from 1700 mm to 4300 mm for different regions in the country. These included daily rainfalls from trace amounts to 162 mm. Rainfall events produce much higher infiltration rates. For example; the maximum daily rainfall in Vancouver International Airport for the year 1993 was 33 mm. For Port Mann landfill it was even higher. To create the hydraulics in the refuse similar to 33 mm/day, an infiltration rate of 2300 ml/day was needed. An infiltration rate of 2300 ml/day was chosen as the highest infiltration rate which gives an HRT of 18 days. Other HRTs higher than this were selected up to 200 days which corresponded to the lowest flow rate available in the pump. Failure of methanogenesis was expected within the wide range of HRTs used 18 - 200 days. Over the 300 day period there was no sign of failure of methanogenesis. Therefore columns 16 and 18 were given very low HRTs of 6 and 3 days (infiltration rates 5600 ml/day and 11200 ml/day respectively) in order to see a breakthrough infiltration rate. An infiltration rate of 11200 ml/day simulates the hydraulics for a daily precipitation of 170 mm. This is similar to the highest daily rainfall for Sri Lanka mentioned earlier. After 55 days of these low HRTs there was no sign of failure of methanogenesis. Since HRTs lower than this are not realistic it was decided that there is no breakthrough HRT beyond which methanogenesis fails. Therefore further lowering of HRT was not done. During phase III, HRTs of all the other columns were decreased to 13 days. This was done to see whether there is an effect from the original HRT (phase II HRTs) on the behavior of the columns (characteristics of leachate and gas) when the HRT is lowered. Chapter 4. Experimental Methods and Analytical Procedures 46 4.3 Methodology-Phase I Construction, refuse filling and preparation of the columns were done with the intention of making 18 identical columns. It was necessary to confirm this before starting the experiments to see the effects of HRT. Once the experimental set-up was completed continuous addition of water at a rate of 1150 ml/day (HRT = 35 days) was started. Sampling and analysis of gas and leachate were done every two weeks except for the third set of samples which were taken three weeks after the second sampling. Volume of gas produced was measured weekly using the wet gas meters. Gas was analyzed for CH/L, CO2, N2 and 02. Leachate was collected in sampling bottles set at the end of the drain tubes. Leachate was analyzed for VFA, COD, total organic carbon, inorganic carbon, volatile solids, dissolved solids, total solids, NHz — N, TKN, zinc, iron, sodium, pH, specific conductance, chlorides and alkalinity. Column 16 was chosen to do a tracer study to confirm the HRT assigned to the columns. A slug of LiCl was added and leachate was analyzed for Li. Samples were taken daily until the peak of the curve has passed, then every two days for about 14 days and randomly after that to complete the tracer curve. During this period only few columns established methanogenesis completely. But it was necessary to move to the next phase of the experiments as flushing of the columns was reducing measurable concentrations. Delaying the initiation of the HRT changes could have resulted in an inability to detect leachate changes. 4.4 Methodology-Phase II After 163 days of preliminary runs, the new column HRTs (18, 60, 120 and 200 days) were developed in the columns by changing the flow rates from 1150 ml/day to 2300, 600, 330, and 230 ml/day respectively. HRTs were assigned in triplicates. When selecting Chapter 4. Experimental Methods and Analytical Procedures 47 Column # Experimental condition HRT(day) Flow rate(ml/day) 1,3,4 60 600 2,7,10,13,16,18 35 1150 5,8,9 120 330 6,15,17 200 230 11,12,14 18 2300 Table 4.3: Experimental Design for Phase II triplicates, columns with identical gas composition and gas production pattern were taken. Six columns were left at the original HRT (35 days) as controls. Table 4.3 shows the experimental design for the Phase II. Sampling and analysis of leachate and gas were done bi-weekly (at the beginning), tri-weekly (middle of phase II) and monthly (towards the end). Gas production rates were measured by taking wet gas meter readings weekly. Analytical parameters for gas composition and leachate were same as phase I except chlorides were not measured since they decreased to the levels not detectable by the chloride ion electrode. A tracer study was carried out using LiCl as the tracer, to confirm the HRTs assigned. A slug of tracer was added to each column and leachate was analyzed for Li. Sampling frequency of leachate for the tracer was determined for each column (HRT) according to the stage of the tracer curve. For example for lower HRTs at the beginning and near the peak, sampling was done every day and then every other day. But for the tail end of the curve, samples were taken weekly and bi-weekly. Tracer curves for the columns 6, 15 and 17 were not complete enough by the end of phase II. Therefore column 15 was left out from the phase III to complete the tracer curve. Before the tracer curve was complete in column 15 the experiments were stopped due to the failure of the pump after running continuously for 600 days. Chapter 4. Experimental Methods and Analytical Procedures 48 Column # Experimental condition HRT(day) Flow rate (ml/day) 1,2,3,4,5,6,8,9,11,12,14,17 13 2800 7,10 35 1150 15 200 230 16 6 5600 18 3 12000 Table 4.4: Experimental Design for Phase III 4.5 Methodology-Phase III As a trial for phase III of the experiments, columns 16 and 18 were given very low HRTs, 6 (flow rate = 5600 ml/day) and 3 (flow rate = 11200 ml/day) days respectively. After 68 days of trial experiment, all the columns except columns 7, 10, 15, 16 and 18 were given an HRT of 13 days (flow rate = 2800 ml/day). Columns 7 and 10 were left at original HRT to do another tracer study. Column 15 was left unchanged to complete its tracer curve. Leachate and gas were sampled weekly at the beginning and bi-weekly after that. Gas was analyzed for Ci74, C02, N2 and 02. Leachate was analyzed for VFA, COD, total organic carbon, inorganic carbon, pH, specific conductance and alkalinity. Gas production rates were measured by taking wet gas meter readings weekly. Table 4.4 summarizes the experimental design for the phase III. Tracer studies were done to columns 7 and 10 to see whether there was any change of HRT in these columns after 8 months, due to decomposition. A slug of tracer was added to each column and the leachate was analyzed for Li. Leachate was sampled daily until the peak of the curve had passed and randomly after that. Chapter 4. Experimental Methods and Analytical Procedures 49 Time Phase I Phase II Phase III * Frame 10/04/93-3/18/93 3/18/94-1/13/95 1/13/95-3/29/95 Time 163 days 300 days 75 days Column # Infiltration HRT Infiltration HRT Infiltration HRT Rate(ml/day) (day) Rate (ml/day) (day) Rate (ml/day) (day) 1 1150 35 600 60 2800 13 2 1150 35 1150 35 2800 13 3 1150 35 600 60 2800 13 4 1150 35 600 60 2800 13 5 1150 35 330 120 2800 13 6 1150 35 230 200 2800 13 7 1150 35 1150 35 1150 35 8 1150 35 330 120 2800 13 9 1150 35 330 120 2800 13 10 1150 35 1150 35 1150 35 11 1150 35 2300 18 2800 13 12 1150 35 2300 18 2800 13 13 1150 35 1150 35 2800 13 14 1150 35 2300 18 2800 13 15 1150 35 230 200 230 200 16 1150 35 1150 35 5600 6 17 1150 35 230 200 2800 13 18 1150 35 1150 35 11200 3 Table 4.5: Summary of Experimental Conditions during the Research. *Note: Phase III for columns 16 and 18 were started on 11/16/94 as a trial for the Phase III 4.6 Methodology-Phase IV After running the experiment at the HRTs in phase III for 75 days, the addition of water to all the columns was stopped; and the water was allowed to drain. Gas was analyzed for the following 90 days for CH±, CO2, N2 and 02- Gas production rates were measured for 112 days by taking wet gas meter readings weekly. A summary of experimental conditions for phases I, II and III of the study is given in Table 4.5. Chapter 4. Experimental Methods and Analytical Procedures 50 4.7 Tracer Experiments Tracer tests were conducted at different stages of the research as described in Sections 4.3 - 4.5. Mass of tracer used in each test are given in Table 4.6. Column # LiCl mass used (g) Phase I Phase II Phase III 1 — 5 — 2 — 5 — 3 — 5 — 4 — 5 — 5 — 5 — 6 — 5 — 7 — 5 10 8 — 5 — 9 — 5 — 10 — 5 10 11 — 7 — 12 — 7 — 13 — • 5 — 14 — 7 — 15 — 5 — 16 9.9 5 — 17 — 5 — 18 — 5 — Table 4.6: LiCl Mass used in Tracer Studies Chapter 4. Experimental Methods and Analytical Procedures 51 4.8 Analytical Procedures Sampling of leachate and gas were done at time intervals as discussed in Sections 4.3, 4.4, 4.5 and 4.6. Leachate was directed to sampling bottles for a period depending on the flow rates in the columns. Sampling, handling and preservation times before analysis were kept to a minimum. Most analysis were done on the same day of sampling. The majority of the tests were conducted in accordance with Standard Methods (A.P.H.A. et al., 1992). The exception was COD for the samples with COD less than 100 mg/L. Samples were diluted using distilled water where necessary. 4.8.1 pH A Beckman 44 pH meter with automatic temperature compensation was used to deter mine the pH of the samples. The meter was calibrated daily, prior to measurements, using two standard buffer solutions of pH 4.0 and 7.0. Detection limit = 0.01 pH units. 4.8.2 Volatile Fatty Acids (VFAs) The volatile fatty acid determination was conducted using a Hewlett-Packard 5880A gas chromatograph, equipped with a Flame Ionization Detector (FID) using the method described in Supelco Bulletin 751. Helium was used as the carrier gas. Volatile fatty acids analyzed include; acetic, propionic, butyric, iso-butyric, valeric and 2-methylbutyric. Samples were acidified with 5% phosphoric acid to bring the pH below 3, 1 ml of the sample was dispensed to VFA vials and stored at 4 °C until analysis. Samples were kept frozen at -17 °C in sealed plastic bottles, when preserving to pH below 3 was delayed for more than 12 hrs after sampling. Detection limit = 1 mg/L for each volatile fatty acid. Chapter 4. Experimental Methods and Analytical Procedures 52 4.8.3 Chemical Oxygen Demand (COD) Samples were analyzed for COD using the dichromate reflux procedure outlined in Stan dard Methods (A.P.H.A. et al., 1992) when the COD is within the range 100 - 900 mg/L (detection limit = 20 mg/L). Samples were diluted depending on the expected COD of each sample to fit to the above range. When the COD was below 100 mg/L, the proce dure was done according to the HACH company DR/2000 spectrophotometer procedure manual. COD dichromate reflux method for the range 0 - 150 mg/L was used (detection limit = 3 mg/L). 4.8.4 Total Organic Carbon (TOC) and Inorganic Carbon (IC) TOC and IC were determined on a Shimadzu Total Organic Carbon Analyzer (Model TOC-500) using a series of low and high standards, as described in the Instruction Manual (Shimadzu Corporation, 1987). Samples were diluted using distilled water for TOC where necessary. Inorganic Carbon was analyzed on undiluted samples. TOC was calculated using the relationship TOC = TC - IC. Detection limit = 1 mg/L. 4.8.5 Alkalinity Total alkalinity was measured by titrating the samples to an end point pH of 4.5 with sulfuric acid. Normality of sulfuric acid (between 0.2 N and 0.02 N) used was decided based on the expected alkalinity of the samples so that the titrant volume is about 20 ml. One normality was used for all the samples in one day. A sample volume of 25 ml was used. Samples were analyzed within 4 hours of collecting. Detection limit = 5 mg CaC03/L. Chapter 4. Experimental Methods and Analytical Procedures 53 4.8.6 Specific Conductance Conductivity was measured using a BACH-SIMPSON Ltd.(TYPE CDM 3) conductivity meter. 4.8.7 Solids Total Solids (TS) and Volatile Solids (VS) Both TS and VS analyses were performed as outlined in Standard Methods (A.P.H.A. et al., 1992). Total solids were determined by evaporating a known volume of well-mixed sample in a Fisher Isotemp (Model 350) forced draft oven at 104 °C. To measure the volatile solid content the residue was ignited at 550 °C in a Lindberg muffle furnace (Type 51828). Detection limit = 6 mg/L. Total Suspended Solids (TSS) Total suspended solid content of the samples was analyzed in accordance with Standard Methods (A.P.H.A. et al., 1992). A known volume of sample was vacuum filtered through pre-washed and oven-dried Whatman 934-AH glass microfibre filter and dried at 104 °C for TSS analysis. Detection limit = 3 mg/L. 4.8.8 Nitrogen TKN Total Kjeldahl Nitrogen was measured by digesting the samples in a BD-40 Technicon Block Digester with concentrated H2SO4 and K^SO^ to liberate all organically bound nitrogen. Analysis was performed colorimetrically following the instructions in the Lachat Chapter 4. Experimental Methods and Analytical Procedures 54 QuickChem Automated Ion Analyzer according to QuickChem Method No. 10-107-06-2-E. Detection limit = 0.1 mg N/L. Ammonia Nitrogen Samples were filtered (Whatman #4), preserved to pH less than 2 by addition of con centrated sulfuric acid, and refrigerated in plastic tubes at 4°C. Ammonia nitrogen was analyzed by the automated phenate method using Lachat QuickChem Automated Ion Analyzer in accordance with the Method No. 10-107-06-1-Z. Appropriate dilutions were done using distilled water where necessary. Detection limit = 0.05 mg N/L. 4.8.9 Metals Zinc, iron and sodium were analyzed in accordance with the Standard Methods (A.P.H. A. et al., 1992). Fifty milli-liters of sample was digested with cone. HNO^ and analyzed on an atomic adsorption/atomic emission sprectophotometer (Thermo Jarrel Ash Cor poration, model No. VIDEO 22) using atomic absorption. Detection limits at the most sensitive wave lengths are 0.002 mg/L as Na, 0.01 mg/L as Zn and 0.05 mg/L as Fe for Na, Zn and Fe respectively. For the tracer study, Lithium was analyzed in accordance with the Standard Methods (A.P.H. A. et al., 1992) on undigested samples. Flame emission method was used in atomic adsorption/atomic emission sprectophotometer. 4.8.10 Chloride Chloride was measured initially by the Mercuric Nitrate Method in accordance with the Standard Methods (A.P.H.A. et al., 1992). Due to the turbidity and color of the samples it was not possible to detect the end point accurately. Therefore a chloride ion electrode Chapter 4. Experimental Methods and Analytical Procedures 55 with pH meter Model 50 from Fisher Scientific was used. 4.8.11 Gas Analysis Gas sampling was done two days prior to leachate sampling. Sampling was done from each column through the gas sampling ports using an 1 ml Hamilton syringe and rapid injection into a Fisher-Hamilton Gas Partitioner (Model 29), using helium as the carrier gas and a thermal conductivity detector. Gases were identified by comparing the peak areas with known standards that were used to determine response factors. 4.9 Statistics Standard deviations were calculated using the statistics package Systat for windows ver sion 5. Simple linear regression analysis was done for zinc and iron concentrations with pH and CH4 production rate using Microsoft Excel Version 5. A confidence level of 0.05 was used to perform analysis of variance (ANOVA) and when F > Fcrmcai null hypothesis was rejected. Chapter 5 Results and Discussion 5.1 Introduction A complete description of the methodology of the research is given in the Chapter 4. In this section an introduction to the contents of this chapter is presented. Also the general performance of the columns and the problems encountered during the research which will be helpful in the interpretation of data, are presented. Phase I was done to establish an understanding of the performance of all the columns and even though care was taken to produce identical refuse columns, the columns behaved differently. This gave the opportunity to observe the effects of HRT under different stages of the refuse decomposition and leachate characteristics. Phase I also gave the opportunity to acknowledge the differences in characteristics of the columns instead of assuming they would all behave similarly due to the efforts went into producing identical columns as one would generally expect. The columns were sealed after filling with refuse and adding anaerobic digester sludge. Therefore, a continuous decrease of available organics in the system occurred during the study. When the HRTs were changed at the beginning of phase II and phase III, available organics and the stage of the decomposition were likely different, even though the leachate from each of the columns was nearly identical. Due to the above mentioned differences, only the gas composition was directly com pared between the columns and phases II and III (i.e., HRT). As explained in the Chapter 4, water was pumped to the columns from an overhead 56 Chapter 5. Results and Discussion 57 tank. This tank was fed from a nearby tap with a very low flow rate. Because of the very low flow rate from the water tap, accumulation of dirt in the valve stopped the flow to the tank. On three occasions during the 550 day experiment (day 120, 390 and 500), there was not enough water in the tank to pump. As a result of this, air was pumped to the columns. The N2 and 02 data points, shown in the gas composition, confirm this. During the experiment, columns 7 and 10 had an HRT of 35 days (predicted) through out the research and were considered as controls. During phase I and II columns 2, 13, 16 and 18 also had an HRT of 35 days (predicted) and are also considered as controls for those phases. These were considered as controls with respect to the changes in op erational variables. As any researcher on landfills would know one cannot have/consider a landfill to be a control with respect to the characteristics of leachate being constant but might be able to have with respect to gas composition as this tends to remain con stant over a longer period. Due to these, direct comparison of leachate characteristics in terms of numbers will not be done, rather trends were compared. Gas characteristics comparisons were done with respect to these columns. To observe the effects of Hydraulic Retention Time (HRT) on landfills, it was neces sary to establish a relationship for HRT in landfills and means of controlling it. A model to determine HRT in landfills was developed and is discussed in Section 5.2. Tracer studies were done at different stages of the research to confirm the HRTs assigned in the columns and to strengthen the established relationship. Results of these are discussed in Section 5.2.1. The general characteristics of leachate and gas are discussed in Sections 5.3 and 5.5. The effects of HRT on landfill gas and leachate are presented and discussed in Sections 5.4 and 5.6. Pollutants released to the environment are discussed in Section 5.7. Microenvironments and carbon released to the environment are discussed in Sections 5.8 and 5.9, respectively. Effects of HRT on landfill leachate and gas characteristics are Chapter 5. Results and Discussion 58 reviewed as a whole in Section 5.10. Potential applications of the findings are discussed in Section 5.11. Figures in this chapter are presented at the end of respective sections or sub sec tions. Predicted HRTs were used in the discussions. Raw data for gas and leachate characteristics are given in Appendices F and G. 5.2 Hydraulic Retention Time for Landfills HRT in landfills is very difficult to predict. It is dependent on many factors such as, a leachate collection system (whether it provides free drainage or not), depth of landfill and again on saturated and unsaturated depths, compaction of refuse etc.. HRT in landfills can change due to many causes. For example; change in depth of refuse or rate of infiltration changes retention time. With increasing rainfall if the depth of saturated layer increases, retention time is increased. As in plug flow reactors, HRT in landfills should be predictable if one knows the volume of water in the landfill. However, for landfills, unlike reactors, it is not directly measurable. For an ideal plug flow reactor HRT is defined as in Equation 2.1. It is assumed that the flow rate through refuse is plug flow. But water holding capacity of a reactor filled with refuse is much less than the actual volume of the reactor; even less, when the reactor is designed to be free draining. It is proposed by this author that the following relationship given in Equation 5.2 holds true for the HRT in the landfill. Chapter 5. Results and Discussion 59 For unsaturated landfills; HRT = — (5.2) Q Where; S = Volumetric water holding capacity of the solid waste in the landfill X Volume of the solid waste in the landfill (L3) Q = Flow rate through the landfill (L3T_1) Water holding capacity of the reactor (landfill) is the total amount of water that can be sorbed by the refuse i.e., including moisture at placement in the refuse. This is often known as field capacity (Section 2.3.2). Water holding capacities of the columns were estimated before starting the experi ments. Moisture content of the refuse at placement was measured to be 36 % wet weight basis (57.5 % dry weight basis). Water sorbed was measured by saturating the refuse columns for four days and then letting them drain. Addition of the amount of water sorbed and moisture at placement gives the water holding capacity. Water sorbed by each column was different, as shown in Table 5.1. When estimating the initial moisture content, samples were taken for the total refuse mass, not for each column. Therefore, 18.95 L of moisture at placement is an average value for all the columns. As such, differ ences in water absorbed could be due to differences in moisture at placement. Therefore when calculating HRTs, average moisture holding capacity for all the columns (i.e., 36.5 L) was taken. Field capacity (water holding capacity) of the refuse was 36.5% volume basis and 69% wet weight basis (i.e., 365 mm/m). This is comparable to the results published by Holmes, 1980 (Table 2.1) for the density of 600 kg/mz, but much higher than the value, 100 mm/m, reported by Rovers and Farquhar (1973). Chapter 5. Results and Discussion 60 Column # Volume of Moisture water absorbed at placement S (L) (L) (L) 1 16.65 18.95 35.6 2 17.86 18.95 36.81 3 17.88 18.95 36.83 4 18.31 18.95 37.26 5 15.83 18.95 34.78 6 18.02 18.95 36.97 7 13.06 18.95 32.01 8 17.75 18.95 36.70 9 19.36 18.95 38.31 10 18.61 18.95 37.56 11 21.61 18.95 40.56 12 16.37 18.95 35.32 13 18.19 18.95 37.14 14 18.94 18.95 37.89 15 18.34 18.95 37.29 16 15.75 18.95 34.70 17 17.01 18.95 35.96 18 16.59 18.95 35.54 Average 17.56 18.95 36.5 SD 1.79 — — Table 5.1: Moisture Absorbed and Field Capacities of the Columns In this research HRT was controlled by regulating the flow rate (infiltration rate). Height of the refuse was kept the same in all the columns. The bottoms of the refuse lysimeters were filled with pea gravel to ensure free draining (i.e., no saturated depths). HRTs were calculated using the Equation 5.2. Where S = 36.5 liters and Q being the flow rate through the column. Flow rates were measured by collecting leachate at the bottom from time to time and the average was used in the calculation of the HRT predicted. Chapter 5. Results and Discussion 61 Example: For columns 1, 3 and 4 Average flow rate (Q) = 600 ml/day Water holding capacity (S) = 36.5 liters from Equation 5.2 HRT 36500 ml/(600 ml/day) = 60.8 day 5.2.1 Tracer Experiments To confirm the model developed and the HRTs assigned to columns a tracer study was conducted. The tracer response curves are shown in Figures 5.1 - 5.5. From the tracer curves it can be seen that there are no multiple peaks. This indicates that channeling was not present in these columns. The mean residence time (HRT) and variance of a tracer curve is calculated using Equations 5.3 and 5.4 when data is collected by instantaneous readings (Levenspiel, 1984). j _ E£r(**+i + *t)(ci+i + c*)(*i+i - u) (5.3) JXl(U+l + U)2(ci+1 + Cj)(ti+1 - tj) -2 ^Zl{ci+l + Ci)(ti+l-U) (5.4) Where; t Mean residence time (T) Variance (T2) U ith time the concentration of tracer measured (T) Concentration of the tracer at ti (ML-3) Chapter 5. Results and Discussion 62 From the Tracer Curve Recovered Column Tracer Mass # t (day) a2(day2) (%) 1 78 1170 19 3 79 1267 21 4 79 1286 19 2 37 470 17 7 42 463 15 10 48 331 20 13 48 359 19 16 35 490 23 18 39 474 19 5 118 2622 18 8 136 2321 17 9 160 1659 17 11 28 298 21 12 30 264 19 14 27 321 23 Table 5.2: t, a2 and Percentage of Mass of Tracer Recovered The mean residence time and the variance for the curves (except for columns 6, 15 and 17 where tracer curves were not complete enough) were estimated and presented in the Table 5.2. Levenspeil (1984) warns of the limitation of this approach to finding the mean residence time (HRT) when the tracer disappears from its flowing phase either by some form of sorption onto solid or by transfer to another phase. LiCl is considered the least sorbing tracer available. The percentage of mass of tracer recovered from the columns is given in the Table 5.2. It can be seen from the data that a very high percentage of tracer was sorbed into the refuse. The long tails of the tracer curves are due to the tracer desorbing from the refuse and was consistent for all the tracer curves. It could be ideal if one could do the tracer experiments until after the desorption is completed and all the tracer mass is completely recovered. Then using these data Chapter 5. Results and Discussion 63 estimation of the part of the tracer curve responsible for sorption and desorption would make it possible to find the actual tracer curve due to the flow characteristics of the refuse column. Such a curve will give an accurate estimate of the t and cr2 where t would give the mean HRT. When obtaining complete tracer curves are impossible one could look at the early part of the tracer curve to be due to the real hydraulics of the columns and the tail end of the curve to be due to sorption and desorption of the tracer. But the question "where to cut off the tracer curve to get a fair estimate of the actual HRT?" will arise. A wrong cut off point will give wrong HRTs for the columns. HRT of an ideal plug flow reactor is defined by the Equation 2.1. Flow through a plug flow reactor does not follow this idealized flow pattern even in chemical reactors. Nevertheless, HRT is defined by the Equation 2.1 for chemical reactors as well as for bio-reactors. It is used extensively as an operational parameter; a parameter which has been able to differentiate between flow conditions, which has been proven to be related to the performances of the reactors. Also it has facilitated the design of the reactor configurations to meet required performances. In these, absolute correct values for HRT were not necessary. Plug flow in a landfill could be far from ideal. Due to all these above mentioned reasons the author looked at the tracer curve in the following way. The peak of the tracer curve represents the time when the maximum number of particles reached the bottom of the lysimeters. Also either sides of the maximum concentration represents a high percentage of the tracer recovered. All the tracer curves demonstrated a consistent pattern. Therefore the time of the peak was chosen as the HRT of the columns. Absolute correct values for HRT are not necessary whereas a consistent means of measuring a difference in HRT is. Table 5.3 shows the predicted HRTs and actual HRTs taken from the tracer curves. Figure 5.6 shows the distribution of the observed HRTs. Chapter 5. Results and Discussion 64 Column # Predicted HRT (day) From the Tracer Curve Observed HRT (day) Mean HRT (day) 1 60 60 60 3 60 60 60 4 60 60 60 2 35 16 25 7 35 23 25 10 35 36 25 13 35 36 25 16 35 16 25 18 35 20 25 5 120 87 117 8 120 120 117 9 120 145 117 6 200 200 200 15 200 190 200 17 200 215 200 11 18 16 17 12 18 18 17 14 18 16 17 Table 5.3: Comparison of Predicted and Observed HRTs It can be seen from the results that the predicted HRT is close to the peak of the tracer curve, if not the same, for most lysimeters. These results show that the Equation 5.2 appears to predict the HRT reasonably well in the lysimeters. This can be extended to landfills. Water holding capacity is the field capacity of the landfill. Since most modern landfills keep records of the quantity of the refuse deposited, composition of the refuse and landfill cross sections, field capacity of the site can be estimated. Therefore, HRT for the landfill for different rainfall patterns can be calculated using Equation 5.2, once the landfills have been fully wetted. Chapter 5. Results and Discussion 65 The first tracer curve for column 16, shown in Figure 5.7, gave an HRT of 22 days. From the tracer curve in Figure 5.2, column 16 has a peak concentration at 16 days. Also, a second tracer study was done for columns 7 and 10. Figure 5.8 shows the comparison of the tracer curves for these two columns at two different stages of decomposition. When the tracer study was done for the first time in column 16, the refuse was fairly new. By the time the second tracer study was started, the refuse has decomposed to some extent. From the tracer curve for column 10 it is seen that with decomposition HRT decreased from 36 days to 30 days. The tracer curves for column 7 shows that the peak concentration occurred at the same time as before. But the spread of the curve towards the left suggests reduction of retention time for some of the infiltrating water. Water holding capacity (field capacity) of the refuse decreases with decomposition. Therefore, according to the Equation 5.2, HRT decreases. This argument is strengthened by the tracer curves for 6 different columns which have the same flow rate (Figure 5.2). Columns 2, 16 and 18, that have high gas production, fall close together and show lower HRTs than columns 10 and 13 which had very low gas production and were in the very early stages of decomposition at the time of the tracer study. These observations indicate that the HRT decreases with the decomposition of the refuse. This is in accordance with the Equation 5.2, as S decreases with the decomposition of the refuse. Chapter 5. Results and Discussion 66 30 T Time (day) Figure 5.1: Tracer Response Curve for HRT=18 days 25 T 100 Time(day) Figure 5.2: Tracer Response Curve for HRT=35 days er 5. Results and Discussion 67 25 T Time(day) Figure 5.3: Tracer Response Curve for HRT=60 days 25 x Time (day) Figure 5.4: Tracer Response Curve for HRT=120 days Chapter 5. Results and Discussion 68 25 -r Time (day) Figure 5.5: Tracer Response Curve for HRT=200 days 250 T 0 -I 1 1 : 1 1 0 50 100 150 200 Predicted HRT (day) Figure 5.6: Comparison of Observed HRTs Chapter 5. Results and Discussion 35 T 69 Time (day) Figure 5.7: Tracer Response Curve for column 16 100 Time(day) Figure 5.8: Comparison of Tracer Response Curve for Columns 7 and 10 at Different Stages of Decomposition (a is for the second tracer study) Chapter 5. Results and Discussion 70 5.3 General Characteristics of Landfill Gas (Phase I) Characteristics of gas in landfills are affected by many environmental parameters. This research was aimed at determining the effects of HRT on landfill leachate and gas char acteristics. Methane production rates in the columns are shown in Figures 5.9 - 5.14. These show the gradual increase and then decrease of the gas production which occurs in a normal landfill. This trend was expected as discussed in Section 2.7. Shown in Figures 5.15 - 5.20 are cumulative CH4 production in the columns, which also show the gradual decrease in methane production. Figures 5.21 - 5.38 show the composition of gas in the columns throughout the study period. These show the gradual increase in CH4 concentration. Composition of gas was different from column to column. CH4 concentration in the columns ranged from 30 - 55% at the end of preliminary runs. After the columns were filled, they were seeded with anaerobic digester sludge. This gave the refuse a good start in methanogenesis. All the columns were at the start of the decomposition stage III (refer Figure 2.4) with respect to waste degradation stages except column 16 which was in the latter part of the decomposition stage III. No definite relationship was observed between gas production rate and the composition of gas in the columns at the beginning of the experiments (phase I). But with time towards the end of phase I, when the CH4 concentration increased, gas production increased. Figures 5.39 - 5.44 show the gas production rates for the columns. Gas production rates and gas compositions were different from column to column even with great care taken to produce identical refuse columns. In setting up the experiment, and after adding anaerobic digester sludge, all of the columns were sealed except for exit gas tubes to prevent air entry. As stated earlier, the exit gas tubes were connected to wet gas meters as they were calibrated. Columns 16, 7, 18 and 1 were the first columns to be connected. All but 10 and 13, were connected over the next period of two weeks. Chapter 5. Results and Discussion 71 Columns 13 and 10, because of mechanical problems, were connected about 6 weeks after the first group. Once the gas meter was connected to a column it became completely sealed against air entry. This was not considered to be that significant since the tubes were only 5 mm in diameter and 1.5 - 4 m long. With the exit flow of gas produced in the column, diffusion of 02 was considered negligible. However, after being connected to a gas meter, the pressure in the column builds up until it is able to push a 2 inch water column in the gas meter. This increase in pressure appears to assist the gas production. This was speculated from the observations that column 16 being the first to be connected had the highest gas production and columns 10 and 13, being the last to be connected, had the lowest gas productions. During the experiments it was observed that increasing amounts of C02 were dissolved in leachate with increasing infiltration rates. Therefore the amount of gas produced is different from the amount of gas measured through the meters. Solubility of CH4 is very small compared to that of C02. As such CH4 production rates (calculated from measured CH4 concentration and measured gas production rates) were considered to be a better parameter for comparisons than the estimated total gas production rates (addition of estimated C02 dissolved and measured gas production). Estimates of total gas production were done for those columns with lower dissolved solids and are presented in Appendix A. In addition inaccuracies that would arise in such estimates for the rest of the columns are discussed. Chapter 5. Results and Discussion 12000 10000 + -a 8000 72 6000 + o o CL I X o 4000 2000 50 100 150 200 Time (day) 250 300 350 12000 10000 ST "O c o o O o 8000 V f= 6000 4000 + 2000 ¥ 300 350 400 450 500 Time (day) Phase IV 550 600 Figure 5.9: Methane Production Rate in Columns 1-3 300 350 400 450 500 550 600 Time (day) Figure 5.10: Methane Production Rate in Columns 4-6 Chapter 5. Results and Discussion 10000 -r Phase I 74 0 "a 2 a. 1 x o 9000 --8000 --% 7000 + "D -§ 6000 c o 50 100 150 200 Time (day) 250 300 350 ro -o o 0 n TJ 2 D. •ST 1 X o + + Phase I + 300 350 400 450 500 550 Time (day) Figure 5.11: Methane Production Rate in Columns 7-9 600 Chapter 5. Results and Discussion 75 3000 2500 + 5 2000 Phase I Phase c 0 'o 3 TJ 2 1 X o 1500 1000 4-500 50 100 150 200 Time (day) 250 300 350 4500 T Phase IV 300 350 400 450 500 Time (day) 550 600 Figure 5.12: Methane Production Rate in Columns 10-12 Chapter 5. Results and Discussion 76 4000 3500 ~ 3000 CD E 2500 Phase I •13 -*-14 -c—15 50 Phase 100 150 200 Time (day) 250 300 350 Phase IV 300 350 400 450 500 Time (day) 550 600 Figure 5.13: Methane Production Rate in Columns 13-15 7000 -r 6000 4-a 5000 c 4000 + o o 2 Q. X 2000 O 1000 T 0 300 Phase IV 350 400 550 450 500 Time (day) Figure 5.14: Methane Production Rate in Columns 16-18 600 Chapter 5. Results and Discussion 78 Figure 5.15: Cumulative Methane Production in Columns 1-3 Time (day) Figure 5.16: Cumulative Methane Production in Columns 4-6 Chapter 5. Results and Discussion 79 Time (day) Figure 5.17: Cumulative Methane Production in Columns 7-9 Time (day) Figure 5.18: Cumulative Methane Production in Columns 10-12 Chapter 5. Results and Discussion 80 Figure 5.19: Cumulative Methane Production in Columns 13-15 Time (day) Figure 5.20: Cumulative Methane Production in Columns 16-18 Chapter 5. Results and Discussion 90 T 81 HRT = 60 days 13 days •CO-2 •0-2 •N-2 •CH-4 100 200 300 400 Time (day) 500 i — — 600 700 Figure 5.21: Composition of Gas in Column 1 100 200 300 400 Time (day) 500 600 700 Figure 5.22: Composition of Gas in Column 2 Chapter 5. Results and Discussion 82 90 -r Figure 5.23: Composition of Gas in Column 3 H RT = 35 days H RT = 60 days 13 days Time (day) 90 -r 80 --Figure 5.24: Composition of Gas in Column 4 Chapter 5. Results and Discussion 90 13 days 100 300 400 Time (day) Figure 5.25: Composition of Gas in Column 5 13 days 100 200 300 400 Time (day) 500 600 Figure 5.26: Composition of Gas in Column 6 Chapter 5. Results and Discussion 80 84 70 + 20 + 10 HRT = 35 days •CO-2 •0-2 •N-2 •CH-4 100 200 300 400 500 600 Time (day) 700 Figure 5.27: Composition of Gas in Column 7 HRT = 35 days HRT = 120 days 13 days 100 200 300 400 Time (day) 500 600 700 Figure 5.28: Composition of Gas in Column 8 Chapter 5. Results and Discussion 90 ao + HRT=35 days HRT=120 days 13 days fl H tt'^B 85 •CO-2 •0-2 •N-2 •CH-4 100 200 300 400 Time (day) 500 H H-600 700 Figure 5.29: Composition of Gas in Column 9 HRT = 35 days •CO-2 •0-2 •N-2 •CH-4 100 200 300 400 Time (day) 500 600 700 Figure 5.30: Composition of Gas in Column 10 Chapter 5. Results and Discussion 90 T HRT = 35 days HRT = 18 days 86 13 days 100 200 300 400 Time (day) 500 600 700 Figure 5.31: Composition of Gas in Column 11 100 200 300 400 Time (day) 500 600 700 Figure 5.32: Composition of Gas in Column 12 Figure 5.33: Composition of Gas in Column 13 HRT =18 days 13days 100 200 300 400 Time (day) 500 600 700 Figure 5.34: Composition of Gas in Column 14 Chapter 5. Results and Discussion 88 Time (day) Figure 5.35: Composition of Gas in Column 15 100 200 300 400 500 600 700 Time (day) Figure 5.36: Composition of Gas in Column 16 Chapter 5. Results and Discussion 89 Time (day) Figure 5.37: Composition of Gas in Column 17 Time (day) Figure 5.38: Composition of Gas in Column 18 Chapter 5. Results and Discussion 20000 T Phase I Phase II Time (day) 18000 Phase Phase Phase IV 300 350 400 450 500 550 600 Time (day) Figure 5.39: Gas Production Rates in Columns 1-3 650 Chapter 5. Results and Discussion 91 16000 -r 14000 Phase I Phase o 12000 TJ 50 100 150 200 Time (day) 250 300 350 16000 14000 D CD Phase II Phase Phase IV -§ 12000 f 10000 4-£ 8000 o TJ g CL 6000 + K 4000 4-2000 4-300 350 400 450 500 Time(day) 550 600 650 Figure 5.40: Gas Production Rates in Columns 4-6 Chapter 5. Results and Discussion 92 Phase I Phase 20000 50 100 150 200 Time (day) 250 300 350 20000 Phase II Phase Phase IV 16000 >> CD T3 S12000 T c o T3 P CO CO O 8000 + 4000 300 350 400 450 500 550 Time (day) Figure 5.41: Gas Production Rates in Columns 7-9 600 650 Chapter 5. Results and Discussion 93 Phase I Phase II 8000 7000 + co T3 o 6000 5000 « 4000 -a p CO O 2000 50 100 150 Time (day) 200 250 300 350 8000 -r Phase Phase IV ro 2000 300 350 400 450 500 Time (day) 550 600 650 Figure 5.42: Gas Production Rates in Columns 10-12 Chapter 5. Results and Discussion 94 50 100 150 200 Time (day) 250 300 350 8000 Phase IV 7000 o TJ 6000 E 5000 + S 4000 4-o D TJ g al CO D 0 3000 2000 1000 +} 300 13 14 15 350 400 550 600 450 500 Time (day) Figure 5.43: Gas Production Rates in Columns 13-15 650 Chapter 5. Results and Discussion 95 Phase I Phase 12000 > 10000 TJ 8000 c o o 6000 TJ o CO o o 4000 4-2000 50 100 150 200 Time (day) 250 300 350 12000 >: 10000 o TJ c o TJ TJ O a. CO o O 8000 6000 4000 2000 + -- Phase IV -K-16 \ -*-17 Phase III for Phase III for -0-18 W 16 & 18 W 17 1 —I 1 1 H 1 1 300 350 400 550 450 500 Time (day) Figure 5.44: Gas Production Rates in Columns 16-18 600 650 Chapter 5. Results and Discussion 96 5.3.1 Methane potential of the Refuse Columns Cumulative CH4 production by the end of the experiments for the columns are tabulated in Table 5.4. They ranged from 16 - 76 L/kg of dry refuse. CH4 potential for these columns is 470 L/kg of dry composite refuse based on the available organics in the columns and assuming organics are 100% biodegradable. The potential methane production from the refuse columns was estimated based on an assumed stochiometri. From Emcon Associates (1980); empirical formulae for food waste and non food organic wastes are CieH^OgN and CZOZHZMOIZSN respectively. The mass of CH4 that can be produced assuming 100% conversion of the given con stituent to CO2, CH4 and NH3 is given by the Equation 5.5 (Parkin and Owen, 1986). CnHaObNc + [n- a/4 - 6/2 + 3c/4]#20 -[n/2 - a/8 + 6/4 + 3c/8]C02 + [n/2 + a/8 - 6/4 - 3c/8]C*H4 •+ cNH3 (5.5) Using the empirical formula for food waste CIQ,H270SN and the Equation 5.5; CieH2708N + 6H20 -»• 7C02 + 9C#4 + NH3 361 g of food waste —> 9 moles of CH4 From PV = nRT CH4 potential at 20°C from 1 kg of food waste = (9X0.082X293/0.361) liters = 600 liters Using the empirical formula for non-food organic waste C203^334Oi38^V and the Equa tion 5.5; C203 #334Oi38iV 4- 51.25#20 -> 94.6C02 + 108.4C#4 + NHS 4992 g of non-food organic waste —•> 108.4 moles of CH4 Chapter 5. Results and Discussion 97 From PV CH4 potential at 20°C from 1 kg of food waste Wet weight of paper Wet weight of garden waste Total wet weight of non-food organics Dry weight of non-food organics CH4 potential due to non-food organics Total wet weight of food waste in a column CH4 potential due to food waste CH4 potential from refuse in one column Total wet weight of non organics in the column CH4 potential from 1 kg of dry composite refuse CH4 potential from 1 kg of wet composite refuse nRT (108.4X0.082X293/4.992) liters 521 liters 8X1.93 kg 15.44 kg 8X1.2 + 4 kg 29.04 kg 29.04X(l-0.36) kg 18.58 kg 18.58 X 521 9680 liters 8 X 2 kg 16 kg 16 (1-0.36) X 600 liters 6144 liters 15824 liters 7.6 kg 15824/(18.58+10.24+7.6 X 0.64) 470 liters 15824/(29.04+16+7.6) 300 liters CH4 potential from the anaerobic digester sludge was not included in the calculations. From these columns 3 -16% of the potential CH4 was recovered during 630 day period. Distribution of CH4 potential from food waste, garden waste and paper are 38.8%, 28.7% Chapter 5. Results and Discussion 98 and 32.5% respectively. Barlaz et al. (1989) observed that in their experiment very little solid hydrolysis occurred during the early stages of the decomposition. It can be assumed that the CH4 produced is basically from the food waste. That even though CH4 production rates are decreasing in the columns, theoretically 95 - 75% (if the organics are 100% degradable) of the CH4 potential is still left in -the columns which will be slowly excercised with time. This is further discussed in Section 5.9. Table 5.5 compares CH4 production rates from this study with those of other studies. The range of ultimate methane yields observed is comparable with the other studies. CH4 production rates at the end of the study were still higher than the other studies in the Table 5.5 (except Barlaz et al., 1989). Therefore it is reasonable to expect that most of the CH4 potential will be exercised with time. Chapter 5. Results and Discussion 99 Column Cumulative CH4 CH4 Produced # Produced liters per kg of dry composite refuse (liters) (m3/tonne) 1 1451 43 2 2565 • 76 3 736 22 4 1447 43 5 2197 65 6 2128 60 7 2557 76 8 2528 75 9 1289 38 10 865 26 11 1084 32 12 838 25 13 710 21 14 832 25 15 1260 37 16 2203 65 17 539 16 18 1325 39 Table 5.4: Comparison of CH4 Produced from the Columns Chapter 5. Results and Discussion 100 Source Ultimate methane yield (m3/dry kg) Annual rate of methane production (mz/dry kg/yr.) Comments This work 0.016-0.076 0.01-0.041* 0.018-0.12 (max) MSW and anaerobic digestor sludge; range for 18 cells Fawcett and Ham, 1986 0.032-0.090 (range) 0.071 (control) 0.0081-0.021 (range) 0.017 (control cell) Mountain View, California, USA controlled landfill (field project) Barlaz et al., 1989 0.087 0.29 Laboratory incubation of fresh refuse in 2L containers for 111 days at 41°C with leachate recycle and neutral ization; water added to 73% (wt/wt) Ehrig, 1991 0.078-0.11 (range) Laboratory incubation of fresh refuse mixed with composted refuse (2:1) in 120 L containers for 300 to 400 days at 30°C with leachate recycle; water added to 65% (wt/wt) Jenkins and Pettus, 1985 0.022 (max) Laboratory incubation of landfill cores (15 cm dia. X 76 cm long at 37°C; assuming 50% CH4 from total gas generation of 0.043 mz/(drykg)/yr Wreford, 1995 0.005 Burns Bog landfill, Vancover, B.C., Canada Table 5.5: Comparison of CH4 Yields and Annual Production Rates; *- CH4 production rate for the last sampling (adapted from Bogner and Spokas, 1993) Chapter 5. Results and Discussion 101 5.4 Effect of HRT on Landfill Gas Characteristics (Phases II, III and IV) Composition of gas was affected by the HRT. Increasing HRT from 35 days resulted in a decrease in CH4 concentration. The opposite was observed in columns where HRT was lowered from 35 days. During phase III, when the HRTs were lowered even further (Table 4.4), CH4 concentration increased to fairly high values, (as high as 92% in column 18) with corresponding decreases in CO2 concentration. Figure 5.45 shows the CH4 concentration versus HRT, at the steady state conditions. HRTs were controlled by controlling the infiltration rates in the columns. For the lowest HRT, 3 day, (column 18 in phase III) the infiltration rate was 11200 ml/day. In this column CO2 concentration was less than 8%. With high infiltration, CO2 produced will not be released to the gas phase resulting in higher CH4 concentration in the gas stream. If this was the only effect, gas production rates should decrease since part of the CO2 stayed in the leachate. But change in HRT did not change the gas production pattern other than the sudden increase shortly after switching HRTs (Figures 5.39 - 5.44). This sudden increase is due to displacement of gas by increased water inflow. Once the columns were adjusted to the new high water inflow, gas production rates fell back into the earlier trend; decreasing, increasing or steady. If the CO2 dissolved were estimated and added to the gas production measured it would show an increase in overall gas production. According to the literature, CO2 partial pressure affects methanogenesis (Hansson, 1979; Hansson, 1982; Hansson and Molin, 1981a,b). The removal rate of acetic acid was sig nificantly affected by the increase of carbon dioxide partial pressure, while butyric acid removal, which does not produce carbon dioxide, was not affected (Hansson, 1979; Hans son, 1982; Hansson and Molin, 1981a,b). In their experiments at lower CO2 partial pressures (0.2 atmospheric), acetate degradation was four times higher than that at 1 Chapter 5. Results and Discussion 102 atmospheric C02- The conversion of acetic acid to methane is by far the most important part of the methane forming process (about 70%) (Christensen and Kjeldsen, 1989). A decrease in CO2 partial pressure should enhance methanogenesis (Hansson, 1979; Hansson, 1982; Hansson and Molin, 1981a,b). Therefore, the increase in CH4 concen tration observed during low HRTs could also be due to the enhanced methanogenesis. Theoretically, when there is no water flowing one would expect the CH4 concentration to decrease since all the CO2 produced is released to the gas phase. Data showed that the CH4 concentration at steady state dropped after the pump was stopped (i.e., no infiltration). CH4 concentration in phase IV can be considered as CH4 concentration of gas produced (no CO2 dissolved in infiltrating water). In phases I, II and III, measured CH4 concentrations are higher than the CH4 concentration of gas produced due to CO2 being dissolved in different rates of infiltrating water (230 ml/day - 11200 ml/day). A small increase in CH4 concentration (from the CH4 concentration before the HRT was lowered in phase III) was seen in columns 1, 2, 3, 5, 6, 8, 9, 15, 16 and 17 (Table 5.6). Columns 7 and 10 which can be considered as controls, decreased their CH4 concentra tion after the pump was stopped. This is expected, since C02 that would have dissolved in leachate is in the gas stream. Also, for columns 11, 12 and 14, there was a decrease in CH4 concentration. These three columns had HRTs of 18 days (2300 ml/day), which is fairly low compared to the other columns at that time and had comparatively high CH4 concentration due to CO2 being in infiltrating water during phase II also. A base amount of CH4 cannot be found for these three columns. Column 15 did not go through a period of low CO2 partial pressure. No improvement in methanogenesis was expected in this column. Data shows that there was an increase in methanogenesis. Column 15 started to increase its pH with a decrease in VFAs by the end of phase II. Increase in CH4 is due to the enhancement of methanogenesis. When the HRT was higher than 60 days (600 ml/day) there was no significant effect on Chapter 5. Results and Discussion 103 Column Before Phase III Phase III CHA Remarks # CH4 Infiltration infiltration content after content (%) (ml/day) (ml/day) Phase III (%) 1 52 600 2800 53.6 increased 2 54.8 1150 2800 55.8 increased 3 52.2 600 2800 55.2 increased 4 54.8 600 2800 54.8 increased 5 49.7 330 2800 54.9 increased 6 53 230 2800 55.6 increased 7 57.8 1150 1150 55.8 decrease explained 8 52.9 330 2800 55.3 increased 9 53.7 330 2800 55.8 increased 10 59 1150 1150 56.1 decrease explained 11 60.8 2300 2800 57.7 m.h.i.b.v. 12 65.2 2300 2800 54.8 m.h.i.b.v. 13 57.4 1150 2800 55.8 m.h.i.b.v. 14 63.6 2300 2800 55.9 m.h.i.b.v. 15 50.2 230 230 54.4 increase explained 16 54 1150 5600 56.2 increased 17 48.1 230 2800 56.5 increased 18 59 1150 11200 56.5 decrease unexplained Table 5.6: Comparison of CH4 concentration before Phase III and after Phase IV; m.h.i.b.v. =must have increased from the base value CH4 concentration (Figure 5.45). HRTs higher than this were achieved by even smaller infiltration rates. When the CO2 is produced in the bacterial cells it will start moving away from the cell and will be in water as long as the carbonic acid system allows. With lower flow rates (higher concentrations of dissolved CO2 will shift the equilibrium to the left) most of the CO2 will be released into the gas stream. Lower flow rates accompanied by the higher concentrations of dissolved constituents further decrease the potential of the CO2 to be in the carbonic acid system. As a result of the high CO2 partial pressure, there was no increase in methanogenic activity. Chapter 5. Results and Discussion 104 Comparison of CH4 production rates is difficult due to different decomposition histo ries of the columns. However some observations are possible as there are sets of columns with similar cumulative methane production prior to the changes in HRTs. As shown in Figure 5.46 columns 2, 5 and 6 had similar CH4 production during phase I. At the end of phase II, column 2 had the highest methane production followed by column 5 in the order of increasing HRT. Similar comparison between columns 15 and 1 which had the same CH4 production also showed that at the end of phase II lower HRT (column 1) had higher CH4 production. Another pair of columns that had similar CH4 production during phase I is 7 and 8 (Figure 5.17). HRT of column 8 was increased to 120 days while column 7 was not changed. By the end of phase II column 7 had higher CH4 production than column 8. Columns 12 and 13 showed the same effect (Figure 5.48). Column 12 started CH4 production earlier than column 13 but they both had similar CH4 production towards the end of phase I and at the beginning of phase II. Column 12 showed higher CH4 production (lower HRT than column 13) towards the end of phase II which also suggests that lower HRT increased the methanogenesis. For all sets lower HRT columns had increased methanogenesis relative to the higher HRT columns. In summary when there were similar phase I starting rates, CH4 production was higher for columns with shorter HRTs. Chapter 5. Results and Discussion 105 Figure 5.46: Comparison of Cumulative CH4 Production of Columns 2, 5 and 6 Chapter 5. Results and Discussion 106 Time (day) Figure 5.47: Comparison of Cumulative CH4 Production of Columns 15 and 1 Figure 5.48: Comparison of Cumulative CH4 Production of Columns 12 and 13 r Chapter 5. Results and Discussion 107 5.5 General Characteristics of Leachate (Phase I) Leachate was characterized for VFA, COD, total organic carbon (TOC), volatile solids, dissolved solids, total solids, chlorides, NHo, — N, TKN, zinc, iron, sodium, pH, specific conductance and alkalinity. During phase I, when all the columns had similar HRTs of 35 days (infiltration rate = 1150 ml/day), all the parameters analyzed showed a similar pattern except metals and pH. At the beginning, concentrations were different for all the columns but within 3 months they all converged to smaller similar values. pH values in all the columns were between 5.2 and 5.5. After about two months, pH in some columns started to decrease and some started to increase. These are discussed in detail in Section 5.6.1. Metals (iron, sodium and zinc) had very different concentrations and showed random patterns during phase I. These are discussed in detail in Sections 5.6.9, 5.6.10 and 5.6.11. 5.6 Effect of HRT on Landfill Leachate (Phase II and III) Leachate characteristics were affected by the HRTs. During phase II, HRTs were changed from 35 days to higher values and lower values. Higher HRTs (in most of the columns) resulted in increasing the concentrations in all the constituents except pH. Lower HRTs resulted in decreasing all constituent concentrations except pH. These are discussed in the following sections under each parameter. During phase III, HRTs were decreased to very low values (13, 6 and 3 days). This resulted in decreasing all the constituent concentrations except pH and alkalinity. Some columns decreased their pH and some columns increased their pH. With respect to alka-linities, some columns maintained steady values, others decreased. Chapter 5. Results and Discussion 108 5.6.1 pH Figures 5.49 - 5.53 show the change in pH with time, during different phases of the experiment. It can be seen from these figures that pH ranged from 4.6 to 7. There was CH4 production in all these columns even if pH was below 5.5. These pH values are typical for lysimeter studies, whereas for full scale landfills the range of pH observed are typically higher (Table 2.3). At the beginning of the experiments pH in all the columns were between 5.2 and 5.5. After about two months when the leachate constituent concentrations decreased, the pH started to increase for high CH4 production columns and decrease for the others. Columns with high CH4 production (cumulative above 130 L) had a trend of increas ing pH up to about 6.5 to 7.5 during the phase II irrespective of HRTs. Columns with lower cumulative CH4 production than 130 L responded to changes in HRT. For columns 1, 3 and 4, where HRTs were increased to 60 days, the pH continued to decrease for some time and only started to increase with increasing CH4 production (VFAs are consumed). In columns 15 and 17 (HRT - 200 days), pH kept decreasing until the end of phase II. De crease in pH coincided with the increase in VFA concentrations. When the VFAs started to decrease, the pH of the two columns started to increase slowly. Column 6 where HRT was also increased to 200 days started to show a pH increase soon after changing the HRT. This column had high CH4 production (cumulative 154 L). Therefore, decrease in VFAs was observed shortly after starting phase II and hence the increase in pH. CH4 production in columns 11, 12 and 14 was low (cumulative 58, 26.5 and 38.5 L respectively by the end of phase I) and each had a pH of 5.3 when their HRTs were lowered to 18 days. Their pH started to increase shortly after (except 11 which took a little longer than others) and reached pH values of above 5.8 by the end of the phase II. Columns 10 and 13 (cumulative CH4 production 23 and 27 L), where HRTs were not Chapter 5. Results and Discussion 109 changed, did not change their pH trend (they had a decreasing trend and was steady after starting phase II) until they reached steady state conditions with respect to gas composition. After they reached 50% CH4 concentration, the pH started to increase. Columns 12 and 13 both had the same CH4 production. Column 12 had a decrease in HRT and column 13 did not change. Increase in pH in column 12 is possibly due to the decrease in HRT which is favorable for methanogenesis. During phase III the HRTs of all the columns (except 7, 10 and 15) were dropped to 13, 6 and 3 days from various HRTs ranging from 18 to 200 days. Infiltration rates adopted to get HRTs of 13, 6 and 3 days were 2800, 5600 and 11200 ml/day. By the end of the phase II, pH of all the columns that had high CH4 productions were between 5.7 and 7.2. Also columns 11, 12 and 14 which did not have high CH4 production as the above columns but had low HRTs, had pH in the above range. During phase III, when the HRTs were lowered, all the columns that had pH values above 5.8 (columns 2, 4, 5, 6, 7, 8, 9, 11, 12, 14, 16 and 18) showed a pH decrease within a week, except column 11 and 14 where there was no change. These columns (2, 4, 5, 6, 7, 8, 9, 16 and 18) except 11, 12 and 14 had established high CH4 production by the end of phase II. Also the C02 concentration in the gas phase decreased. Evidence that the inorganic carbon levels also increased in these columns, suggests that some of the C02 was dissolved in leachate. This could account for the decrease in pH. Columns 11, 12 and 14 already had a fairly low HRT of 18 days. Their pH values were 5.8, 5.9 and 5.9 respectively. Columns 12 and 14 had established pH above 5.8 for about three months, whereas column 11 had been increasing its pH from 4.9 and just entered the above range at the end of phase II. It kept increasing regardless of the change in HRT. Its very active methanogens are indicated by the fast rate of decreasing VFA during the last two months of phase II. Leachate from columns 1, 3, 13 and 17 which had pH below 5.4, started to increase in Chapter 5. Results and Discussion 110 0 50 100 150 200 250 300 350 400 450 500 550 Time(day) Figure 5.49: Change in pH in Columns 11, 12 and 14 pH when HRTs were decreased to 13 days. These columns had high VFA concentrations (830, 800, 615 and 3375 mg/L respectively) at this time. So the dilution of VFAs is the likely reason for increasing pH. This same trend of increasing pH (when HRT was decreased) was observed in columns 11, 12 and 14 which had higher VFAs when their HRTs were decreased during phase II. In summary, the effect of HRT on pH depended on the stage of decomposition (CH4 production) and the leachate VFA concentration at the time. When the HRT was in creased in established high CH4 producing columns, the pH kept increasing since the VFA was being consumed. The pH in low CH4 producing columns decreased since the VFA concentrations increased due to concentration. When the HRT decreased, high CH4 producing columns reduced the pH due to the shift in carbonic acid system. Low CH4 producing columns, which had higher VFA concentrations, increased their pH due to the dilution of VFAs. Chapter 5. Results and Discussion 111 Figure 5.50: Change in pH in Columns 2, 7, 10, 13, 16 and 18 HRT = 35 days HRT = 60 days HRT=13days •1 •3 •4 0 50 100 150 200 250 300 350 400 450 500 550 Time(day) Figure 5.51: Change in pH in Columns 1, 3 and 4 Chapter 5. Results and Discussion 7 112 6.5 ol 5.5 " HRT = 35 days HRT = 120 days 13 days --1 1 H 1 1 1 1 1 r— 1 1 50 100 150 200 250 300 Time(day) 350 400 450 500 550 Figure 5.52: Change in pH in Columns 5, 8 and 9 H RT = 35 days , H RT = 200 days 13 days except 15 50 100 150 200 250 300 Time(day) 350 400 450 500 550 Figure 5.53: Change in pH in Columns 6, 15 and 17 Chapter 5. Results and Discussion 113 5.6.2 Volatile Fatty Acids (VFA) Figures 5.54 - 5.56 show the change in VFA with time. At the beginning of the research (phase I), VFA concentrations of the columns ranged from 23,000 - 45,000 mg/L. This is typical for a young landfill leachate. These leachates are referred to as young leachate at the beginning since the refuse was fresh. By the end of phase I (a period of 163 days), VFA concentrations decreased to a range of 1400 - 6200 mg/L. The columns with high CH4 production showed a faster decrease in VFAs than the low CH4 producing columns. During this period, the columns where HRTs were changed from 35 days to lower HRTs (columns 11, 12 and 14), continued reductions of VFA concentrations were observed. Columns where HRTs were increased, showed increases in VFA concentrations at the beginning but started to decrease later. Columns 15 and 17 where HRTs were increased to 200 days, showed increased VFAs up to a period corresponding to one HRT and then started to decline. In columns 5, 8 and 9 with HRT of 120 days VFAs increased for a short period of time and then started to decrease. Columns 1, 3 and 4 where HRTs were shifted to 60 days, VFAs increased for about 50 days before they started to decline. Column 6 with higher HRT (200 days) did not follow the above pattern. This column had very high CH4 production and, as such, the VFA was being consumed quickly. By the end of phase II, VFA concentration in columns 2, 7, 8, 9, 12, 14, 16 and 18 were very low (in the range 0-20 mg/L), while for the other columns, it fell into a range of 130 - 4250 mg/L. When HRTs were lowered to 13, 6 and 3 days, VFA concentrations of all the columns decreased very rapidly. This is expected due to dilution as well as due to increased methanogenesis. VFAs were analyzed in terms of acetic acid, propionic acid, butyric acid and va leric acid. During the early stages of the experiments butyric acid and acetic acid were Chapter 5. Results and Discussion 114 dominant. With time the acetic acid portion increased. Towards the end of the exper iments, where the concentrations were small, the only VFA detectable was acetic acid. Distribution of VFAs in all the columns are given in Figures 5.57 - 5.74. The VFAs in high gas producing columns fell off to negligible values midway during phase II. Other columns also decreased their concentrations towards the end of phase III. Therefore, in Figures 5.57 - 5.74 towards the end of the time axis, the concentrations are very small. Once the VFAs decreased to small values during the analysis the peaks of the response curves were sometimes not detectable, even if the presence of most of the VFA types were seen. Therefore, 100% acetic acid towards the end of time scale does not necessarily mean there were no other types of VFAs. No relationship was observed between HRT and the distribution of VFA types. During phase III when the C02 partial pressure decreased in the columns acetic acid concen trations should decrease faster than propionic acid since the C02 partial pressure affects only acetic acid conversion but not the propionic acid (Hansson, 1979; Hansson, 1982; Hansson and Molin, 1981a,b). This could not be seen due to the low concentrations. Mass of VFA released to the environment are discussed in Section 5.7. Chapter 5. Results and Discussion 115 Time (day) Figure 5.54: Change in VFA in Columns 1-6 Chapter 5. Results and Discussion 116 60000 -r Phase I 50000 H-40000 cn -§ 30000 < LL > 20000 10000 + Phase 100 200 Time (daypO 400 P III 4- 8000 500 Figure 5.55: Change in VFA in Columns 7-12 60000 50000 40000 -§ 30000 < u. > 20000 4-10000 4-Phase 100 200 300 Time (day) 400 500 Figure 5.56: Change in VFA in Columns 13-18 Chapter 5. Results and Discussion 100% 80% 117 60% c CD O S. 40% 20% 4\ 11 I 11 I 111 111 11 I I • 111 1) I I 11 I 11 I j 11 111 I u I u I u I u I 1 & others ^ butyric • propionic • acetic 0% I"!1 |ii|H|ii|ii|H|ii|ii|ii| ocMOooco^tojom^fojoococnco-i-Time (day) Figure 5.57: Distribution of VFAs in Column 1 100% 80% 3* 60% c 0- 40% B others • butyric • propionic • acetic 20% 0% H—I S cvioin'd-cnoococnOT-00i--^-CT)CMr-T+CD00-i-in O CM O 00 CD r- ro CM T-I-I-CMCMCVCTCO Time (day) Figure 5.58: Distribution of VFAs in Column 2 Chapter 5. Results and Discussion 100% -TO i 80% 118 S> 60% c CD E CD Q. 40% 20% 0% S others butyric • propionic • acetic OCNOOOCO^CVIOlO'S-COOOCOCnCO't-Time (day) Figure 5.59: Distribution of VFAs in Column 3 100% -I-80% ^ 60% c a> 0 1 40% 4] 20% 0% I 1 II I B others & butyric • propionic • acetic ocxioooco^-cvioin^-cncncocnco-i-— cviinooi-'frOiCMi'^'d-coco-!-1^ CD CM Time (day) Figure 5.60: Distribution of VFAs in Column 4 Chapter 5. Results and Discussion 100% TH 119 80% 60% CD CD o- 40% 20% |ii|ii|ii|ii|ii|ii|ii|H|ii|ii|ii|ii|ii|ii|ii|ii|H|U| & others butyric • propionic • acetic 0% ocviocncD^+c\jOLnrj-o)oocoo5co-i— •^r^oicNjinoo-t-rfcric\ir~-^fcoQO-i-Time (day) Figure 5.61: Distribution of VFAs in Column 5 100% 80% 60% c CD U £ 40% 20% 0% El others El butyric • propionic • acetic |ll|ll|ll|ll|ll|ll|ll|ll|ll|ll|tl|U|U|U|U|U|U|U|U|U|U|U|U|U| ocMOooco-^-cvjoin^tooocoencoT-rrr^cncvjinoo-i-Ti-cncvir^-^-cDcoT-i--i--i-cMCMC\Jcoco'*^'a-m Time (day) Figure 5.62: Distribution of VFAs in Column 6 Chapter 5. Results and Discussion 120 CD Q-S others • butyric • propionic • acetic O CM O coio^tiMOifl'Jciioonffln'-O)CMlOCDT-^-O)<Mls-'^tCD00-i-Time (day) Figure 5.63: Distribution of VFAs in Column 7 100% TH 80% C? 60% c • 40% 20% -H S others butyric • propionic • acetic Time (day) Figure 5.64: Distribution of VFAs in Column 8 Results and Discussion 121 Time (day) Figure 5.65: Distribution of VFAs in Column 9 § others • butyric • propionic • acetic 100% 80% others ^ butyric propionic • acetic 60% c Q) O £ 40% 20% 0% O OJ O 00 CO I— O CM |M|U|LI|U|U|U|U|U|Li[ll[ll|ll|U|U|U|U|U| | | | |JJ_| S cMOin^cncocococo-i-^T-^cncMiv.Ti-coopTr i- CM CM CM CO CO in Time (day) Figure 5.66: Distribution of VFAs in Column 10 Chapter 5. Results and Discussion 122 100% -m 80% 60% c CD E CD Q. 40% I 20% Oo/o jl 1,11,11111,11,11 jl I |l 1,1J 111 |l 1111 |LJtLJ jLJ! |U|II|II|U|U|U|U|U|U|LI|U|U| OCNIOCDCO^CVJOUl'frCOCOCOOJCOi-Ttr>-o)C\jLnoo-i-'!tc»cvji^'*cDoo-i-100% 80% Time (day) Figure 5.67: Distribution of VFAs in Column 11 5 others • butyric • propionic • acetic 3* 60% c CD U I 40% S others ^ butyric • propionic • acetic 20% 0% oc\ioroco-*cMOifi^c»cDcoo>cr>-!-•^r^cncNjLno3-i-'^-cT)Cvir~'^-cooo-i-i-T-i-wtMcMnn^^^w Time (day) Figure 5.68: Distribution of VFAs in Column 12 Chapter 5. Results and Discussion 100% TB 123 80% 3* 60% c 2 CD Q- 40% 20% ll Q0/O III^IIIIIIIIII^^UIUIUILIIH^IJII^IIU^IU^IUIUIUIUIUIUIIIIIJIIJIU^IUIUI OOJOOOCD'a'OJOLO^tCnoOOOCDCOT-Time (day) Figure 5.69: Distribution of VFAs in Column 13 5 others butyric • propionic • acetic 100% TB 5 others Ii butyric • propionic • acetic ocjococo^tcjoin^fojcococncoi-•i-i-'i-cvjcMCJcocoTf^i-'^-m Time (day) Figure 5.70: Distribution of VFAs in Column 14 Chapter 5. Results and Discussion 100% TH 80% 124 60% tz <D o CD Q- 40% 20% 1111111111111111111111111 I I I l"l 5 others • butyric • propionic • acetic 0% I' I'M 'l"l"l"lul ocNjooocD^c\join^-c»oococnco-i-•^t^OTC\iinoD-i--^c»CNjr^^cooO'i-Time (day) Figure 5.71: Distribution of VFAs in Column 15 100% 80% Ce 60% c o g. 40% 20% 0% S others • butyric • propionic • acetic oc\ioooco'*ojOLn'!tcooo 1-1-1-CMCMCMCOCO l"l"l"l l"l"l cn co i-CD 00 T— LO Time (day) Figure 5.72: Distribution of VFAs in Column 16 Chapter 5. Results and Discussion 100% TB 125 c CD O CD a. 90% 80% -H 70% 60% 50% 40% 30% 20% 10% 0% 11111111111111 11111111111U | U | U | U | U | U | U | U | II111111,1111J | LJ | U , U | U | U , U | LJ | oc\ioooco^rcMOif)Tro>oocoo5co-i-•^•t^cniNmoo-i-tcncur^-^cDoo-i-T--T-i-cvjcMc\icocY5^t-^-'^-un Time (day) Figure 5.73: Distribution of VFAs in Column 17 S others E33 butyric • propionic • acetic 100% TB 80% 3" 60% c CD O rJ 40% 20% 0% ocviooocD'jcvioinTfrocococnco-i-•^r^05CMif)oo-i-->*o>c\ir^^-cooo-i-S others ES butyric • propionic • acetic Time (day) Figure 5.74: Distribution of VFAs in Column 18 Chapter 5. Results and Discussion 126 5.6.3 Chemical Oxygen Demand (COD) Change in COD for the columns are given in Figures 5.75 - 5.77. At the beginning of the experiments, COD for the columns were in the range of 42,000 - 62,000 mg/L. COD for all the columns followed the same pattern as VFA during all three phases except column 15 during phase III. HRT of column 15 was not changed during phase III. During this period column 15 had its peak in CH4 production rate. This coincided with the increase in pH and rapid decrease in VFA. But the rate of decrease in COD did not appear to change. Mass of COD released to the environment is discussed in the Section 5.7. Time (day) Figure 5.75: Change in COD in Columns 1-6 Chapter 5. Results and Discussion 127 Phase I P HI T 14000 =B> 40000 E O 30000 O 0 50 100 150 200 250 300 350 400 450 500 550 Time (day) Figure 5.76: Change in COD in Columns 7-12 60000 50000 40000 Phase I Phase P III Q O o 30000 20000 + 10000 + 16000 100 200 300 Time (day) 400 500 Figure 5.77: Change in COD in Columns 13-18 Chapter 5. Results and Discussion 128 5.6.4 Total Organic Carbon (TOC) and Inorganic Carbon (IC) Changes in TOC for the columns with time are given in Figures 5.78 - 5.80. TOC in all the columns during phase I decreased very rapidly. When the HRTs were changed (phase II and phase III), TOC followed the same pattern as VFA. The mass of TOC released to the environment is discussed in the Section 5.7. Figures 5.81 - 5.83 shows the change in IC concentrations in the columns. IC concen trations followed a different pattern. During the early stages of the research, the leachate was very strong and was necessarily diluted for analysis. When samples are diluted, IC can be lost and the results are not accurate. Therefore the initial IC concentrations were not taken into consideration in data interpretation. After about 2 months when leachate concentrations had decreased, IC was analyzed using undiluted samples. After this change in analysis, the IC concentration also had a decreasing pattern for some time and started to increase towards the end of the phase I. When the HRTs were changed (phase II) IC showed no relation to HRT. During phase III when HRTs were decreased to 13, 6 and 3, ICs in all the columns increased to a range of 100 - 300 mg/L. During phase III extra care was taken to limit the dissipation of C02 dissolved by covering the sampling vials with tape until analysis. This must have added to some extent to the increase in IC. This can be seen from the increase in IC in columns 7, 10 and 15 whose HRTs were not changed during phase III. But the increase in other columns was higher than these columns. The decreasing trend of IC is due to leaching out of IC from the landfill mass. With the increase in gas production in the columns an increase in dissolved CO2 in the leachate is expected. This would increase the IC in the leachate. Chapter 5. Results and Discussion 129 Time (day) Figure 5.78: Change in TOC in Columns 1-6 0 100 200 300 400 500 Time (day) Figure 5.79: Change in TOC in Columns 7-12 Chapter 5. Results and Discussion 130 T 6000 100 200 300 Time (day) 400 r 5000 500 Figure 5.80: Change in TOC in Columns 13-18 Phase I , Phase II 50 100 150 200 250 300 Time(day) •1 •2 •3 •4 •5 •6 350 400 450 500 550 Figure 5.81: Change in IC in Columns 1-6 Figure 5.82: Change in IC in Columns 7-12 Figure 5.83: Change in IC in Columns 13-18 Chapter 5. Results and Discussion 132 5.6.5 Alkalinity Figures 5.84 - 5.86 shows the change in alkalinity of the columns during the study period. Initial leachate (phase I) had alkalinities in the range 6800 - 12000 mg CaCOz/L. With time, the alkalinity concentrations decreased until the end of phase I. With the changed HRTs in phase II, irrespective of the HRTs, high CH4 production columns (2, 5, 6, 7, 8, 9, 16 and 18) maintained an alkalinity above 500 mg/L. An increase in alkalinity is expected with the consumption of VFA (Christensen and Kjeldsen, 1989). In columns with low CH4 production, alkalinities kept decreasing. Exceptions to these were columns 15 and 17, where an alkalinity of above 600 mg/L was maintained until the end of phase II. This could be due to the concentration of alkalinity by increased HRT. By the end of phase II, alkalinities of the columns which had high CH4 production and high HRT (columns 5, 6, 8 and 9 had HRTs of 120, 200, 120 and 120 respectively) were in the range 740 - 1060 mg CaCO^/h. By the end of phase II, alkalinities of the columns 2, 7, 16 and 18 which had higher CH4 production and lower HRT (35 days) were 540, 495, 340 and 460 mg CaCOz/L respectively. These were in parallel with their CH4 production rates at the time; 4840, 4050, 3160 and 3280 ml/day respectively. Columns 5, 6, 8 and 9 could maintain the alkalinity produced by methanogenesis due to their lower infiltration rates than columns 2, 7, 16 and 18. During phase III, when the HRTs were lowered to 13, 6 and 3 days, columns that had high alkalinities decreased in concentration showing the effect of dilution with high infiltrating water. But the columns that had low alkalinities around 200 mg/L, did not change due to dilution. It was observed that there is a definite relationship between pH, HRT and alkalinity. This is shown in Figure 5.87. Lower HRT's maintained a pH close to 6 for a wide range of alkalinity. Chapter 5. Results and Discussion 133 Figure 5.84: Change in Alkalinity in Columns 1-6 Time (day) Figure 5.85: Change in Alkalinity in Columns 7-12 Chapter 5. Results and Discussion 134 Figure 5.87: HRT, pH and Alkalinity of the Leachate at Steady State Chapter 5. Results and Discussion 135 5.6.6 Specific Conductance Figures 5.88 - 5.90 show the change in specific conductance in the columns during phases I, II and III. Specific conductance of the initial leachate ranged from 13 - 17 mS/cm. The values in all the columns decreased until the end of phase I. When HRTs were changed in phase II conductivity followed the dilution phenomena. Higher HRT columns (lower infiltration rates) had increased conductivity and lower HRT columns (higher flow rates) decreased in conductivity. In the Port Mann landfill study (Jasper et al., 1987), a decrease in specific conductance with high rainfall (due to dilution) was also observed. Pseudo mass of specific conductance released to the environment is discussed in the Section 5.7. Phase I Phase II Phase III 0 100 200 300 400 500 600 Time (day) Figure 5.88: Change in Specific Conductance in Columns 1-6 Chapter 5. Results and Discussion 136 Phase I o > o ~o c o o 100 200 300 Time (day) 400 500 600 Figure 5.89: Change in Specific Conductance in Columns 7-12 100 200 300 Time (day) 400 500 600 Figure 5.90: Change in Specific Conductance in Columns 13-18 Chapter 5. Results and Discussion 137 5.6.7 Total Solids Total solids ranged from 28,000 - 41,000 mg/L when the experiments were started (Fig ures 5.91 - 5.93). With time total solids decreased until the end of phase I. For new HRTs in phase II, total solids followed the same pattern as organic constituents. High HRT columns increased solids up to a period of close to one HRT and then decreased to stable concentrations. For the lowered HRTs solids decreased faster than it had been observed before lowering the HRT. When the HRTs were lowered in phase III, total solids decreased to very low values in a range 160 - 490 mg/L. Mass of total solids released to the environment is discussed in the Section 5.7. In the Port Mann landfill the total solids concentration stayed constant, irrespective of the seasonal variation in rainfall/infiltration (Jasper et al., 1987). 0 100 200 300 400 500 600 Time (day) Figure 5.91: Change in Total Solids in Columns 1-6 Chapter 5. Results and Discussion 138 Phase 100 200 300 Time (day) 400 500 600 Figure 5.92: Change in Total Solids in Columns 7-12 40000 -p Phase I P III 100 200 300 Time (day) 400 500 Figure 5.93: Change in Total Solids in Columns 13-18 Chapter 5. Results and Discussion 139 5.6.8 Nitrogen (NH3 - N, TKN) Change in TKN and NHZ - N with time are shown in Figures 5.94 - 5.99. TKN values ranged from 250 - 1000 mg N/L at the beginning of the experiment and then decreased rapidly to a range of 10 - 60 mg N/L by the end of phase I. Ammonia Nitrogen was in the range 140 - 475 mg N/L and then decreased to a range 5-60 mg N/L by the end of phase I. TKN concentrations were approximately twice the N Hz — N concentrations throughout the study. This is very different from real landfills where most of the TKN is usually accounted for by NHz — N. For example in Port Mann landfill (Jasper et al., 1987) more than 90% of TKN was NHz — N. Addition of anaerobic digestor sludge could have added extra nitrogen that is not available for landfills. When the HRTs were increased, in columns 5, 6, 8, 9, 15 and 17, the TKN and NHz — N concentrations increased for a short period and then started to decrease. In others (columns 1, 3 and 4) there was a decrease in the rate of decrease in concentration. In columns 15 and 17 where HRTs were also increased, the leachate had an increase in NHz — N and TKN concentrations. After about 200 days, these also started to decrease. In columns 11, 12 and 14, where HRTs were decreased, the decrease in concentrations was faster. Analysis of leachate for ammonia nitrogen was not done for phase III. During this period some of the columns decreased in TKN very quickly. Some of them stayed steady for some time and then decreased. Mass of NHz — N and TKN released to the environment is discussed in the Section 5.7. Chapter 5. Results and Discussion 140 0 100 200 300 400 500 Time (day) Figure 5.94: Change in TKN in Columns 1-6 Time (day) Figure 5.95: Change in TKN in Columns 7-12 Chapter 5. Results and Discussion 141 1200 -r 1000 4-800 4-600 Phase I Phase II PIUY 160 400 200 4-100 200 300 Time (day) 400 500 Figure 5.96: Change in TKN in Columns 13-18 50 100 150 200 250 300 350 Time (day) 400 Figure 5.97: Change in Ammonia Nitrogen in Columns 1-6 Chapter 5. Results and Discussion 142 Time (day) Figure 5.98: Change in Ammonia Nitrogen in Columns 7-12 Time (day) Figure 5.99: Change in Ammonia Nitrogen in Columns 13-18 Chapter 5. Results and Discussion 143 5.6.9 Iron The change in iron concentrations with time, during phases I and II, is given in Fig ures 5.100 - 5.102. They were different from column to column during phase I. For a short period of time concentrations decreased; then concentrations increased (except for columns 16 and 18) towards the end of phase I. During phase II, increasing iron concen trations were seen in columns where HRTs were increased. Columns 11, 12 and 14 where HRTs were decreased, showed decreased concentrations of iron relative to the controls. In other columns, iron concentrations remained steady throughout. These results showed that mobilization of iron continued throughout the experiments. Solubility of iron depends on pH and ORP. Methanogenic bacteria need very low redox potentials and cannot initiate growth at a potential higher than -330 mV (Zehnder, 1978). After this initiation, increases in ORP were shown to decrease methanogenic activity. Methane production rate is an indicator of the levels of ORP in the landfills. Higher CH4 production can be considered a sign of very low ORPs and lower CH4 production can be considered a sign of increasing ORP. But CH± production rate and ORP are not directly correlated. Continuous release of iron was observed, so was the release of carbon to the environment. Carbon released to the environment was dependent on CH4 production rate. Therefore, iron concentrations were analyzed for possible correlations to CH4 production rate. Since solubility of iron depends on pH, iron concentrations were also analyzed for correlation to pH. Summary of these is given in Table 5.7. Regression plots are given in Appendices B and C. Five columns (1, 3, 4, 15 and 17) showed significant negative correlation to pH with correlation coefficients of 0.92, 0.87, 0.63, 0.94 and 0.86 respectively. These columns also showed significant positive correlation to CH4 production rate (0.81, 0.80, 0.49, 0.78 and 0.80 respectively). pH and iron solubility are negatively correlated. Methane Chapter 5. Results and Discussion 144 production and pH are positively correlated. Columns 1, 3, 4, 15 and 17 which showed significant negative correlation with pH and positive correlation with CH4 production had two characteristics in common. Their HRTs were increased in phase II and CH4 productions were low. When the HRT of low gas producing columns were increased, their pH decreased. But their CH4 production rates kept increasing while pH stayed low during the period iron was analyzed. For these columns the effect of increasing HRT gave strong correlation to pH and CH4 production. This is a coincidence with the effect of the increase in HRT in low CH4 producing columns, i.e. kept decreasing their pH while CH4 production was increasing with time. Columns 5, 6, 8, and 9 also increased their HRTs. But the CH4 production rates were higher. They showed positive correlation for CH4 production (0.81, 0.81 and 0.47 for columns 5, 6, and 8 respectively) except column 9 but showed no significant correlation for pH. From these data it is not possible to conclude which of the effects of pH or CH4 production is stronger. Columns 2, 7, 10, 13, 16 and 18 where HRT was not changed during this period only 16 significant correlation with respect to pH (correlation coefficients -0.46). Only columns 10, 16 and 18 showed significant correlation with CH4 production rates (-0.45, -0.47 and -0.64 respectively). HRTs of columns 11, 12 and 14 were decreased. Column 11 showed positive correlation to pH which is the opposite of the effect of pH on iron solubility. Column 11 and 12 showed negative correlation with CH4 production (-0.51 and -0.71 respectively) which is the opposite of the expected effect from CH4 production. Correlations of iron to pH or CH4 production was linked to the changes in HRT and CH4 production stage of the column. These are summarized in Table 5.7 and can be grouped as follows; 1. Columns with low CH4 production and increased HRT in phase II showed strong negative correlation to pH and positive correlation to CH4 production Chapter 5. Results and Discussion 145 2. Columns with low CH4 production and decreased HRT showed very small or no significant correlation to pH and negative correlation to CH4 production except one column 3. High CH4 production and increased HRT showed positive correlation to CH4 production and no significant correlation to pH 4. When the HRTs were not changed, correlations to pH was either very little (negative) or not significant and that for CH4 production was very small (negative) or none except one column showing a correlation of -0.64 to CH4 production These results show that the effects of pH and CH4 production rate on iron concen tration is complicated in these landfill ecosystems and dependent on many other factors. Predictability of correlation of pH and CH4 production to iron concentrations in these columns in the long run is questionable due to the interrelated effects of pH, HRT and CH4 production. What is clear however is that iron continues to be released overtime and that leachate concentration is dependent on a set of factors not fully understood. The mass of iron released to the environment is discussed in Section 5.7. Chapter 5. Results and Discussion 146 pH CH4 Production Column Rate # R Significant R Significant 1 -0.92 yes +0.81 yes 2 — no — no 3 -0.87 yes +0.80 yes 4 -0.63 yes +0.49 yes 5 — no +0.81 yes , 6 — no +0.81 yes 7 — no — no 8 — no +0.47 yes 9 — no — no 10 — no -0.45 yes 11 +0.44 yes -0.51 yes 12 — no -0.71 yes 13 — no — no 14 — no — no 15 -0.94 yes +0.78 yes 16 -0.46 yes -0.47 yes 17 -0.86 yes +0.80 yes 18 — no -0.64 yes Table 5.7: Summary of Correlation Analysis of Iron Vs pH and CH4 Production Rate; yes - significant, no - not significant Chapter 5. Results and Discussion 147 Figure 5.100: Change in Iron in Columns 1-6 Chapter 5. Results and Discussion 148 Figure 5.102: Change in Iron in Columns 13-18 Chapter 5. Results and Discussion 149 5.6.10 Zinc The change in zinc with time is shown in Figures 5.103 - 5.105. Concentrations of zinc in the columns at the beginning were in the range of 0 - 3.6 mg/L. Exceptions to these were columns 4, 6, 9 and 15 which had zinc concentrations of 6.3, 10.1, 8.4 and 21.2, respectively. Within two months, these had decreased to the range 0-3.6 mg/L. Other than this, there was no reduction in concentrations with time during phase I as opposed to other parameters measured. Data showed that continued mobilization of zinc to the environment. ORP and pH affects the solubility of metals. Therefore zinc concentrations were analyzed for correlation with pH and CH4 production rates (CH4 production and ORP are discussed in Section 5.6.9). Correlation plots for pH and CH4 production rates are given in Appendices D and E. Results are summarized in Table 5.8. Zinc concentrations showed significant correlation to pH in columns 2, 3, 5, 7 and 18 (correlation coefficients -0.67, -0.78, -0.47, -0.43 and -0.93 respectively). Columns 10 and 13 showed significant positive correlation to pH (0.47 each). Zinc concentrations showed significant negative correlation to CH4 production in thirteen columns. Column 3 showed positive correlation. These correlations were unpredictable. Decreasing ORP increases increases zinc solubility. With increasing CH4 production pH increases and should decrease the solubility. HRT also affected the pH. This complicates the solubility process. Analysis of the data showed this. Chapter 5. Results and Discussion 150 pH CH4 Production Column Rate # R Significant R Significant 1 — no — no 2 -0.67 yes -0.73 yes 3 -0.78 yes +0.64 yes 4 — no -0.49 yes 5 -0.47 yes -0.58 yes 6 — no -0.41 yes 7 -0.43 yes -0.53 yes 8 — no — no 9 — no -0.63 yes 10 +0.47 yes -0.82 yes 11 — no -0.45 yes 12 — no -0.67 yes 13 +0.47 yes -0.68 yes 14 — no -0.47 yes 15 — no — no 16 — no -0.44 yes 17 — no — no 18 -0.93 yes -0.87 yes Table 5.8: Summary of Correlation Analysis of Zinc Vs pH and CH4 Production Rate; yes - significant, no - not significant Chapter 5. Results and Discussion 151 0 50 100 150 200 250 300 350 400 Time (day) Figure 5.103: Change in Zinc in Columns 1-6 Chapter 5. Results and Discussion 152 0 50 100 150 200 250 300 350 400 Time (day) Figure 5.104: Change in Zinc in Columns 7-12 0 50 100 150 200 250 300 350 400 Time (day) Figure 5.105: Change in Zinc in Columns 13-18 Chapter 5. Results and Discussion 153 5.6.11 Sodium The change in sodium with time is shown in Figures 5.106 - 5.108. Sodium concentrations started within a range 250 - 500 mg/L and decreased with time, converging by the end of phase I. When the HRTs were changed in phase II, sodium concentrations in the columns with higher HRTs increased for some time and started to decrease. Columns where HRTs were decreased, decreases in concentrations were quicker than the columns with no change in HRT. The mass of sodium released to the environment is discussed in Section 5.7. Time (day) Figure 5.106: Change in Sodium in Columns 1-6 Chapter 5. Results and Discussion 154 Time (day) Figure 5.107: Change in Sodium in Columns 7-12 Time (day) Figure 5.108: Change in Sodium in Columns 13-18 Chapter 5. Results and Discussion 155 5.6.12 Chloride The change in chloride with time is shown in Figures 5.109 - 5.111. Chloride in leachate was only analyzed during the phase I. The chloride concentrations in the initial leachate were in the range 340 - 715 mg/L. Within 4 months, the concentrations decreased to a range of 20 - 60 mg/L, except for the column 16 which decreased in concentration to 80 mg/L and then showed an increase to 170 mg/L for the last sampling. Due to the low concentrations and the analytical difficulties (due to interferences) chloride was not measured after these 4 months. 700 T 0 -I 1 1 1 1 1 1 0 20 40 60 80 100 120 Time (day) Figure 5.109: Change in Chloride in Columns 1-6 Chapter 5. Results and Discussion 156 Figure 5.110: Change in Chloride in Columns 7-12 Figure 5.111: Change in Chloride in Columns 13-18 Chapter 5. Results and Discussion 157 5.7 Pollutant Release to the Environment from the Lysimeters Once the refuse is deposited in the landfill, physical, chemical and biological processes will take place. As a result gaseous, dissolved and suspended compounds in the form of leachate and gas are released. In this research it was observed that the releases are different from column to column depending on (but not correlating to all) many factors such as; infiltration rate (HRT), gas production rate (decomposition) etc.. The highest leachate concentrations of all the pollutants measured except inorganic carbon, zinc and iron for all the columns were observed at the beginning of the experi ments. Mass releases of inorganic carbon was not analyzed since the initial concentrations of IC had analytical errors. The analytical difficulties for IC at the beginning of the ex periments were discussed in Section 5.6.4. During phase I all the columns had the same HRT. By the end of this period, all contaminants, except inorganic carbon, iron and zinc, decreased to very low values. Therefore, most of the pollutants were leached to the environment during this period. Tables 5.9 - 5.11 gives the mass of the pollutants leached to the environment during phase I and phase II. Comparison of phase I and II shows that for all the constituents, 70 - 98% of the mass was leached during phase I (except for zinc and iron where 35 - 83% mass was leached). Comparison of concentrations of COD, chloride and ammonia nitrogen for the vol ume of leachate produced was done with the prediction curves for these constituents by Reitzal et al. (1992) and are given in Figures 5.112 - 5.114. COD concentrations are in agreement with the prediction curve except towards the end of the curve where the majority of the concentrations are little higher. After a leachate production of 3.5 liters (corresponds to 100 days) data points shift away from the exponential decay curve. COD concentrations are dependent on biological activity in the landfills. Data on CH4 produc tion and CH4 composition showed that biological activity increased with time. Leaching Chapter 5. Results and Discussion 158 HRT (day) VFA (g) COD (g) TOC (g) Alkalinity (g) Column # I II I II I II I II I II 1 35 60 1974 413 3568 912 855 254 695 104 2 35 16 1898 263 3519 704 850 196 641 254 3 35 60 1942 402 3691 1002 829 281 677 160 4 35 60 1809 342 3435 774 817 225 664 120 5 35 87 2032 239 3927 638 934 180 720 132 6 35 200 1818 134 3370 365 790 99 678 91 7 35 23 1915 193 3524 479 810 140 765 256 8 35 120 2094 319 3625 789 820 227 665 171 9 35 145 1884 217 3498 524 799 151 717 112 10 35 36 2293 669 3939 1641 990 481 745 115 11 35 16 2385 829 4309 1852 1034 572 851 304 12 35 18 2578 522 4162 1126 906 343 789 186 13 35 36 2195 573 3798 1456 934 410 755 103 14 35 16 2740 375 4342 924 1033 267 806 220 15 35 190 1870 404 3716 835 864 231 555 56 16 35 16 1687 58 2926 217 670 51 588 257 17 35 215 1967 334 3590 784 891 211 665 79 18 35 20 1922 134 2952 437 738 101 613 341 Table 5.9: Mass of VFA, COD, TOC and Alkalinity Leached during Phases I and II of soluble organic products with increasing biological activity would increase the COD concentration. Chloride concentrations are not affected by the biological activity. They did not show much scatter as in COD and were well below the chloride prediction curve. Ammonia nitrogen concentrations showed good agreement with the ammonia nitrogen prediction curve. In summary, releases of chloride and sodium were not dependent on the biological activity. Release of organics to the environment is through gas and leachate. These were dependent on the biological activity and continuous release occurred throughout the experiment. Release of zinc and iron are controlled by the chemical characteristics of the refuse mass which is also dependent on the biological activity. Continuous release Chapter 5. Results and Discussion 159 HRT Conductivity Total Solids TKN - N (day) ((mS/cm)Xml) (g) (g) (g) Column # I II I II I II I II I II 1 35 60 1303 323 2530 508 47.9 3.2 25.8 1.3 2 35 16 1337 465 2389 645 65.4 5.6 36.8 4.3 3 35 60 1343 382 2473 618 74.0 5.0 37.6 2.4 4 35 60 1345 303 2572 480 43.2 4.8 28.0 3.0 5 35 87 1418 250 2760 442 65.3 3.6 33.4 2.4 6 35 200 1330 173 2436 286 44.9 2.1 29.1 1.2 7 35 23 1364 438 2515 559 53.6 5.4 33.4 2.5 8 35 120 1340 301 2482 571 46.0 4.3 34.4 2.6 9 35 145 1336 228 2725 379 28.3 2.0 19.4 0.4 10 35 36 1429 541 2882 757 53.8 6.4 21.9 1.3 11 35 16 1546 782 3027 1187 53.2 7.7 31.7 2.8 12 35 18 1436 492 2856 694 43.5 5.0 25.6 1.6 13 35 36 1429 417 2810 632 37.0 4.9 22.3 0.8 14 35 16 1498 541 3000 816 56.2 5.9 31.8 2.0 15 35 190 1245 237 2255 383 77.4 7.1 41.1 4.6 16 35 16 1175 432 2247 547 23.7 4.2 16.3 0.5 17 35 215 1326 235 2574 409 42.7 4.3 25.2 2.2 18 35 20 1234 536 2319 704 28.1 3.7 19.1 1.8 Table 5.10: Mass of Conductivity, Total Solids, TKN and NHz - N Leached during Phases I and II of zinc and iron also was observed. Presence of sulfate in the landfill will precipitate metals as sulfide. This will help decrease metal levels in leachate. But in this work continuous release of zinc and iron was observed indicating absence or presence in very small quantities of sulfates. This is further strengthened by the levels of methanogenesis of the columns. This research involved infiltration rates higher than most of the lysimeter studies published. Therefore one would suspect higher releases to the environment. Data for chloride showed that they are lower than the data used in the Reitzal et al. (1992). Release of organics to the environment depends on the break down of the solid organic Chapter 5. Results and Discussion 160 HRT (day) Iron (g) Zinc 'mg) Sodium (g) Column # I II I II I II I II 1 35 60 9.7 12.5 118 120 18.1 0.5 2 35 16 13.6 18.7 84 42 26.5 2.3 3 35 60 15.8 25.0 67 112 23.5 0.8 4 35 60 18.8 19.0 555 218 26.5 0.6 5 35 87 14.1 11.0 92 23 27.2 1.0 6 35 200 15.1 10.1 475 61 24.9 0.4 7 35 23 17.9 23.6 37 19 24.4 0.8 8 35 120 13.7 8.5 165 62 22.3 0.6 9 35 145 17.5 8.8 695 146 21.4 0.4 10 35 36 14.6 17.4 604 472 18.5 0.8 11 35 16 18.5 34.8 136 212 25.8 1.3 12 35 18 24.0 40.3 311 542 25.2 0.7 13 35 36 21.7 29.2 361 363 24.2 0.8 14 35 16 12.7 14.0 76 67 26.2 1.1 15 35 190 11.3 10.7 1027 337 27.6 0.8 16 35 16 20.6 20.8 82 16 15.7 0.8 17 35 215 9.7 7.0 294 112 18.7 0.6 18 35 20 11.0 8.5 406 90 20.4 1.7 Table 5.11: Mass of Iron, Zinc and Sodium Leached during Phases I and II materials. This was shown by the higher concentrations than the prediction curve with time (towards the end of the graph) when CH4 production was increased (Figure 5.112). Organic carbon release to the environment is further discussed in the Section 5.9. Chapter 5. Results and Discussion 161 70000 T 60000 50000 O) 40000 £ 8 30000 O 20000 10000 4-Y=40000 exp(-0.49X) 5000 4500 4000 Jx * >°$00 3500 - ^ • | 3000 \% •<> w 2500 ;oO • O 2000 -j- O v$o 2.4 6 8 Volume of Leachate per kg of Refuse (L) Y=40000 exp(-0.49X) s 1500 £ 1000 $ J*** 500 * ' * 13 18 23 _4 I I t 0| $o_ 28 33 -«4-38 Volume of Leachate per kg of Refuse (L) Figure 5.112: Comparison of COD with the COD Prediction Curve by Reitzal et al., 1992 Chapter 5. Results and Discussion 162 1800 T Volume of Leachate per kg of Refuse (L) Figure 5.113: Comparison of Chloride with the Chloride Prediction Curve by Reitzal et al., 1992 700 -r Volume of Leachate per kg of Refuse (L) Figure 5.114: Comparison of NHz — N with the NHz — N Prediction Curve by Reitzal et al, 1992 Chapter 5. Results and Discussion 163 5.8 Micro-environments Enhancement of CH4 production with increase in moisture content and moisture move ment can be due to many reasons. Transportation and distribution of nutrients and carbon sources and dilution of inhibitors are the possible primary factors. During phase I of the experiments all the lysimeters were given 1150 ml/day infiltration. Leachate characteristics in all the lysimeters were similar with respect to organic carbon; however, the gas productions were different. Some factors that would have lead to the differences in initiation of gas production were discussed in Section 5.3. After the gas production was initiated, this itself is speculated to be a factor in increasing methanogenesis. During the first 60 days of the experiments, the pH values in all the lysimeters were 5.5 ± 0.2. Lysimeters with high gas production (VFA consumed) showed increasing pH. Higher pH further helps methanogenesis. Lysimeters with low gas production eventhough there is limited VFA consumption had a decreasing pH. This is not favorable for methanogenesis. During phase I all the experimental conditions were identical. Gas production rates and composition of gas were different but leachate constituent concentrations were identi cal with respect to organic carbon. This leads to the speculation that microenvironments are responsible for the behavior of the lysimeters and the constituent concentrations in leachate are not the concentrations in the microenvironments. For example, VFA con centrations in a microenvironment is the difference between VFA produced (by solid hydrolysis and fermentation of sugar) and VFA consumed for gas production (assuming there is no water flowing through the refuse). Hydrolysis and fermentation are depen dent on the removal of VFA by gas production. Barlaz et al. (1989) observed little solid hydrolysis during this period of their study and suggested that feedback inhibition due to accumulated acids. Therefore the majority of the VFAs during the first 60 days are from fermentation of sugars. VFA concentration in the microenvironment cannot be higher Chapter 5. Results and Discussion 164 than the concentration that is inhibitive to hydrolysis and fermentation. Consequently, up to a certain rate of gas production, VFAs are the same in microenvironments when the rate of VFA production (hydrolysis and fermentation) is less than its maximum due to the inhibition. This was seen during first 60 days from leachate VFA concentrations. When the VFAs in microenvironments are similar, the rate of transfer of VFAs to passing water will be the same if the flow rate of water is the same and as such leachate VFA concentrations were nearly identical during the first 60 days. But, with time, gas pro duction rates of some columns increased rapidly. When this happens, VFAs are removed from the microenvironments faster than they are produced. This will decrease the VFA concentrations in the microenvironments. This is reflected by the reduced leachate VFAs in the high gas producing columns. Towards the end of the experiments, leachate VFA concentrations were not detectable in some columns while having high gas productions. 5.9 Carbon Released to the Environment Landfills receive degradable organics from different sources. When the refuse is deposited in the landfills physical, chemical and biological processes occur. Biological processes are responsible for stabilization of the landfill with respect to organics. Hydrolysis of solid organic matter and complex dissolved organic matter to VFAs and alcohols is required for the biostabilization of this organic carbon. Hydrolysis of the organics is the most important process in the landfill stabilization. This is discussed in Sections 5.10 and 5.11. After hydrolysis, these products can be removed from the landfill environment either as gas or in leachate. This will depend on the extent of methanogenesis in the landfill and the availability of infiltration. Also, these two are very much interdependent; methanogenesis is affected by infiltration. The mass of organics removed due to infiltration is dependent on the extent of methanogenesis. Organic carbon in the landfills will be either converted Chapter 5. Results and Discussion 165 to gas or leached with infiltrating water. Initially, most of the organic carbon was leached with infiltrating water while a small portion was converted to CH4 and C0% With time, organic carbon converted to CH4 and CO2 increased, consequently decreasing organic carbon mass in the leachate. From the data obtained during phases I, II and III carbon released to the environment as gas and leachate were estimated. The methods for calculating carbon in leachate and gas are given in Sections 5.9.1 and 5.9.2 respectively with sample calculations. In calcu lating carbon released in leachate VFAs were used instead of TOC since VFA represents the biodegradable portion of TOC. 5.9.1 Carbon in Leachate Organic carbon in leachate was estimated using VFA concentrations. VFAs were analyzed in terms of acetic acid, propionic acid, butyric acid and valeric acid. Amounts of carbon in each were calculated as follows and added to get the total carbon (as carbon) in leachate. Carbon in acetic acid = (Acetic acid cone.)X(24/60,000) g/L Carbon in propionic acid = (Propionic acid cone.)X(36/74,000) g/L Carbon in butyric acid = (Butyric acid conc.)X (48/88,000) g/L Carbon in valeric acid = (Valeric acid conc.)X (60/102,000) g/L Concentration of carbon in leachate = Total of above 4 items Sample calculation: Column 5 for the 126 th day; Acetic acid concentration = 1590 mg acetic acid/L Chapter 5. Results and Discussion Carbon in acetic acid Propionic acid concentration Carbon in propionic acid Butyric acid concentration Carbon in butyric acid Valeric acid concentration Carbon in valeric acid Concentration of carbon in leachate Total carbon leached (Acetic acid conc.)X(24/60,000) g/L 0.64 g/L 440 mg propionic acid/L (Propionic acid conc.)X(36/74,000)g/L 0.21 g/L 803 mg butyric acid/L (Butyric acid conc.)X (48/88,000) g/L 0.44 g/L 540 mg valeric acid/L (Valeric acid conc.)X (60/102,000) g/L 0.32 g/L Total of above 4 items 0.64 + 0.21 + 0.44 + 0.32 g/L 1.61 g/L 1.61 g/L X flowrate 1.61 g/L X 1.15 L/day 1.85 g/day 5.9.2 Carbon in Gas Sample calculation: For column 5 for the 126 th day; PV = nRT Where; P =1 Atmospheric Pressure Chapter 5. Results and Discussion 167 V = Volume of gas in Liters n = Number of moles in the sample T = Temperature of Gas in Kelvin degrees = 20 °C = 20 + 273 °K R = 0.082 L*atm/mol*K n = V/(0.082 X 293) = V/24.026 Concentration of C02 = 46.1% Concentration of CH4 = 46. 9% Rate of gas production = 5.01 L/day Carbon in gas as C02 (g/day) = 12 X moles of C02 = 12 X (C02 volume/24.026) = (12/24.026) X C02 cone. X Rate of gas production = (12/24.026) X 0.461 X 5.01 = 1.15 g/day Carbon in gas as CHA (g/day) = (12/24.026) X 0.469 X 5.01 = 1.17 g/day Total carbon in gas = 1.15 -f- 1.17 g/day = 2.32 g/day Cumulative carbon released in the leachate ranged from 800 - 1500 grams. Lower values were related to high gas production columns and high amounts were related to low gas production columns. Cumulative carbon released in the gas phase ranged from 540 - 2270 grams by the end of phase IV. During the early stages, leachate carried a higher percentage of organic carbon from the landfill. With time, carbon released in the Chapter 5. Results and Discussion 168 gas phase showed an increasing trend. For some columns, the rate of carbon released in the gas reached a peak and then started to decrease during the study period. Others had an increasing trend until the end of experiments. Leachate carbon concentrations were very small towards the end. Cumulative carbon released in gas or leachate was dependent on the gas production of each column. Figures 5.115 - 5.132 illustrates the rates of carbon released and cumulative carbon released as gas and leachate in the columns. Column 10 had the lowest gas production at the beginning and took a long time to get the methanogenesis established. As a result, VFAs were leached unused by the methanogens. Therefore, carbon released in the leachate was high (1375 g of which 1000 g was leached in the first quarter of the experiment). This was the case with all the low gas producing columns. Column 1 and 2 established their gas production from the beginning and kept increasing. The initial VFAs were used by the methanogens and still a portion of these products were leached in the leachate. Column 1 leached a total of 1147 g with 900 g in the first quarter. Column 2 leached a total of 1028 g with 850 g in the first quarter. However, with time, most of the VFAs were consumed by the bacteria, thus increasing the carbon released in the gas phase and decreasing the carbon in leachate. All the high gas producing columns behaved in the same pattern. As discussed earlier, organic carbon released to the environment is dependent on many factors. First of all the availability of soluble organic carbon. When the refuse is placed in landfills, readily biodegradable organic compounds will be hydrolyzed and fermented by fermenting bacteria to volatile fatty acids and alcohols. Therefore, during the early stages of the experiment these can be mobilized and result in high carbon concentrations in leachate. But after this source is depleted, the availability of organics depends on the degradation of solid organics; cellulose, hemicellulose etc.. Therefore, at this stage, organic carbon released to the environment depends on the extent of biological activity within the landfill. This is shown in the Figure 5.133. During phase I, the total carbon Chapter 5. Results and Discussion 169 released to the environment was very similar in all the columns. During phase II, the total carbon released was dependent on the CH4 production Figures 5.133). Summary of carbon releases and total gas produced is given in Table 5.12. Column # Cumulative C Cumulative C Total C Cumulative released in released in released in gas methane gas (g) leachate (g) and leachate (g) produced (L) 1 1275 1148 2423 1451 2 2189 1029 3218 2566 3 658 1128 1786 736 4 1224 1001 2225 1447 5 1991 1099 3091 2197 6 1787 916 2704 2028 7 2150 1005 3155 2557 8 2269 1144 3413 2528 9 1123 976 2099 1289 10 733 1375 2108 865 11 885 1496 2381 1084 12 631 1438 2069 838 13 588 1301 1888 710 14 645 1480 2125 832 15 1094 1128 2222 1260 16 1833 815 2648 2203 17 540 1113 1653 539 18 1054 984 2038 1326 Table 5.12: Summary of Carbon Releases from the Landfill Figure 5.133 shows high gas producing columns released more carbon than the low gas producing columns. Carbon released through leachate had tailed off in all the columns. The trend for high gas producing columns shows that their release of carbon to the environment is decreasing (Figures 5.116, 5.119, 5.120, 5.121, 5.122, 5.123, 5.130 and 5.132). In these columns, the gas production decreased and have released carbon to the environment in the range of 2700 - 3400 grams, except columns 9, 16 and 18. Columns Chapter 5. Results and Discussion 170 9, 16 and 18 released 2100, 2650 and 2040 grams respectively. When the data collection was started, column 16 had 40% CH4 concentration and the highest gas production rate. A reasonable amount of initial carbon released in the gas phase was not accounted for. Column 18 and 16 lost CO2 into the leachate which brought the CH4 concentration of up to about 90%. Carbon in the CO2 lost to leachate was also not accounted for. Therefore, it would be fair to consider that columns 16 and 18 also had the carbon released to the environment in the above high range. Column 9 slowed down in gas production after about 200 days probably due to the increase in HRT. Decrease in CH4 production was observed in both columns 8 and 9. But column 8 started to increase CH4 production after about a month of changing HRT. Column 9 had all the other characteristics associated with high gas producing columns. This column could be an exception. Low gas producing columns released carbon in the range 1650 - 2400 grams. These columns also showed a decreasing trend in gas production. Therefore, most likely these columns would release 50% (or even more) less carbon than the high gas producing columns. All the eighteen columns in this study received the same amount of organic material at the beginning. Therefore, they all had the potential for releasing similar amounts of carbon to the environment. Carbon release was dependent on the CH4 production stage of the columns, indicating the importance of biological activity in sta bilizing a landfill. What could be happening in these low gas producing columns is an interesting point of conjecture. Barlaz et al. 's (1989) results showed that during the first two stages of decomposition soluble sugars are fermented and released increasing VFAs in the leachate. This was not seen in this study, since, when the sampling started all the columns had passed this stage. Highest VFAs and a pH of 5.5±0.2 were measured at the beginning and VFAs had a decreasing trend. This and the increasing CH4 production showed establishing methanogens which were utilizing VFAs from soluble sugar fermentation according to Chapter 5. Results and Discussion 171 Barlaz et al. (1989). Very little solid hydrolysis occurred in their study during the first three phases. With time, carbon released in the leachate decreased due to the decrease in available soluble organics. This could be attributed to either; the VFAs are converted to gas or limiting solids hydrolysis or both. Increasing conversion to gas was seen by the increase in carbon in the gas phase. Some of the columns started to decrease their CH4 production rate which is charac teristic of decelerated methane phase (Barlaz et al., 1989). According to them polymer hydrolysis limited the refuse methanogenesis. Continuous decrease in methane produc tion was suggested to be due to concurrent decrease in polymer hydrolysis and is explained as the preferential use of cellulose and hemicellulose which are less heavily lignified. Once the cellulose and hemicellulose are degraded during this period the remaining refuse be comes high in lignin content. Khan (1977) found in his study the presence of higher proportion of lignin in cellulose products adversely affected the ability to degrade cellu lose by the mixed culture used. In summary Carbon released to the environment during the initial stages will depend on the availability of soluble organic carbon and will be released mainly as leachate. When this source is depleted the hydrolysis of the solid organic carbon will control the release of the carbon to the environment. Hydrolysis of the solids will be controlled by the use of these products by methanogens or it being carried away by infiltrating water; In addition hydrolysis is mediated by extracellular enzymes produced by fermenting bacteria (Jones et al., 1983). These show the interaction of the biological processes in the landfill stabilization process which in turn affects the extent to which the landfill organics are degraded. Chapter 5. Results and Discussion 172 Time (day) 1400 T 700 Time (day) Figure 5.115: Carbon Released to the Environment from Column 1 Chapter 5. Results and Discussion 173 100 200 300 400 Time (day) 500 600 2500 -r ^2000 O) V. ' C o •§1500 O Q) > 1000 o C in Gas • C in Leachate ^^•••••••••grjtarjnrj • rxrunnn .•nD 100 200 300 400 Time (day) 500 600 700 Figure 5.116: Carbon Released to the Environment from Column 2 Chapter 5 Results and Discussion 174 4 T • C in Gas •C in Leachate 100 200 300 400 Time (day) 500 600 1200 1000 + o C in Gas • C in Leachate • ••••••• n^000 100 200 300 400 Time (day) 500 600 700 Figure 5.117: Carbon Released to the Environment from Column 3 Chapter 5. Results and Discussion 175 100 200 300 400 Time (day) 500 600 1400 -r 1200 o ^1000 o .Q O 800 O CD £ 600 o § 400 O 200 0 o C in Gas • C in Leachate DnoaDD°°°°DDDDD  n$ 100 200 500 300 400 Time (day) Figure 5.118: Carbon Released to the Environment from Column 4 600 700 Chapter 5. Results and Discussion 176 0 100 200 300 400 500 600 Time (day) 0 100 200 300 400 500 600 700 Time (day) Figure 5.119: Carbon Released to the Environment from Column 5 Chapter 5. Results and Discussion 177 Time (day) 1800 -r 1600 31400 + §1200 .Q °1000 + CD > 800 -H-D £ O 400 0 o C in Gas • C in Leachate 3 600 + Q° 00° 200 4-D + 0 100 200 300 400 500 600 700 Time (day) Figure 5.120: Carbon Released to the Environment from Column 6 Chapter 5. Results and Discussion 178 0 100 200 300 400 500 600 Time (day) c o •S 1500 + O 351000 f e 3 500 o C in Gas • C in Leachate 0 100 200 —I— 500 300 400 Time (day) Figure 5.121: Carbon Released to the Environment from Column 7 600 700 Chapter 5. Results and Discussion 179 Time (day) Figure 5.122: Carbon Released to the Environment from Column 8 Chapter 5. Results and Discussion 180 1200 T 700 Time (day) Figure 5.123: Carbon Released to the Environment from Column 9 Chapter 5. Results and Discussion 181 Time (day) 0 100 200 300 400 500 600 700 Time (day) Figure 5.124: Carbon Released to the Environment from Column 10 Chapter 5. Results and Discussion 182 0 100 200 300 400 500 600 Time (day) 1600 T 700 Time (day) Figure 5.125: Carbon Released to the Environment from Column 11 Chapter 5. Results and Discussion 183 Time (day) 1600 1400 CM 200 o C in Gas • C in Leachate anna00 0 100 200 500 600 300 400 Time (day) Figure 5.126: Carbon Released to the Environment from Column 12 700 Chapter 5. Results and Discussion 184 Time (day) 1400 -r 700 Time (day) Figure 5.127: Carbon Released to the Environment from Column 13 Chapter 5. Results and Discussion 185 Time (day) Figure 5.128: Carbon Released to the Environment from Column 14 Chapter 5. Results and Discussion 186 Time (day) Figure 5.129: Carbon Released to the Environment from Column 15 Chapter 5. Results and Discussion 187 Time (day) 2000 T 700 Time (day) Figure 5.130: Carbon Released to the Environment from Column 16 Chapter 5. Results and Discussion 188 4T 100 C in Gas C in Leachate 200 300 Time (day) 400 500 600 1200 1000 + o C in Gas • C in Leachate nnnnoDD1300 •••••••DDDD 100 200 300 400 Time (day) 500 600 700 Figure 5.131: Carbon Released to the Environment from Column 17 Chapter 5. Results and Discussion 189 Chapter 5. Results and Discussion 190 3500 3000 + o Total C Released during P II x Total C Released - end of P I A Total C Released - end P I x XX 2500 2000 1500 1000 500 A * XX* o ~o o O o 0 + + + 50 100 150 200 250 Cumulative CH-4 Production (L) 300 350 Figure 5.133: Carbon Released to the Environment in Relation to the CH4 Production Chapter 5. Results and Discussion 191 5.10 General Overview HRT affects landfill leachate and gas characteristics. The effects of HRT on landfill gas composition and leachate pH and organic constituent concentrations were the most noticeable and important with regard to stabilization of landfills. This indicates that HRT affects methanogenesis. Quantitative analysis of the effects was not possible due to the time trends in the data but some observations were possible. These are summarized in Tables 5.13 to 5.15 for the period of phase II. When the HRTs were reduced below 60 days, exponential increase in CH4 concen tration was observed. With the decrease in CO2 concentration to 8% in gas and the increase in IC in leachate, it is evident that a major portion of the C02 stayed in infil trating water. It is suggested that the increase in CH4 concentration is also due to the enhancement of methanogenesis, as a result of decreased C02 partial pressure and other effects such as increasing pH of low gas producing columns and dilution of inhibitive concentrations of VFAs. This is supported by the fact that there was no decreased gas production (Figures 5.39 - 5.44), which is expected when a noticeable portion of produced CO2 was dissolved in the infiltrating water. Also, from the Table 5.6, it can be seen that CH4 concentration has increased after the period of three months with low C02 partial pressure. When the columns had identical decomposition history, lower HRTs showed an increase in CH4 production by the end of the phase II. In addition to these, there are other effects that will come into play due to low HRT (high infiltration); lowering C02 partial pressure, increasing pHs of the low gas producing columns, moisture distribution which is essential for methanogenesis, transport of nutrients and organic carbon in the refuse and dilution of inhibitors. Wreford (1995) analyzed the factors affecting landfill gas composition and production and leachate characteristics at the Vancouver landfill site at Burns Bog. Her results Chapter 5. Results and Discussion 192 indicated that precipitation had the most prominent effect. Cumulative precipitation from 14 days prior to sampling showed the strongest relationship to CH4 production at the individual gas wells. Her observations support the findings of this research. Port Mann landfill and other landfills discussed in Chapter 2 show high organic con centrations in leachate following high rainfall period. This was suspected to be due to the failure of methanogenesis as a result of decrease in HRT. An increase in infiltration rate decreases the HRT, and it does affect the leachate and gas characteristics. But, in this research decreases in HRT due to increase in infiltration rate enhanced the methano genesis. Field studies done by Wreford (1995) showed an increase in CH4 concentration and CH4 production in Burns Bog landfill, Vancouver during the high rainfall periods. Therefore the increase in organic loadings during the periods of high rainfall in Port Mann landfill is unlikely to be due to the failure of methanogenesis as a result of low HRT with high infiltration. In the Port Mann case there was no gas collection system, so parallel measurements were not made. The research data from Rovers and Farquhar (1973) showed a decrease in CH4 con centration from 17% to 6% with an increase in COD, BOD and volatile dissolved solids and a decrease in alkalinity and pH in the resulting leachate. These observations were explained as the failure of methanogenesis during periods of rapid infiltration. The ex cessive infiltration was due to snow melting during spring. They felt since there was only 2°C drop in temperature, the failure could not be due to a decrease in temperature. Reduction of pH was thought to be a result of failure in methanogenesis rather than a cause. The cause of failure was explained as due to the increase in oxidation-reduction potential (ORP) which would have occurred during the melted ice and snow infiltration. However, ORP was not measured in their experiments. Their results showed that the CH4 concentration dropped to 6%. Gas samples were taken from the bottom of the refuse column. When the methanogenesis failed in their Chapter 5. Results and Discussion 193 work (in cell C\) 200 liters of infiltration (calculated from Figure 1 in Rovers and Far quhar, 1973) occurred over a period of approximately 20 days. An average infiltration rate of 4 mm/day took place in this cell over a period of 20 days. Moisture absorbed was 740 liters. And the moisture content at placement was 1505 liters (62% X 2428 L). According to Equation 5.2, these will give an HRT of 224 days (S = 2245 liters, Q = 10 L/day). This is close to the highest HRT (200 days) tested in this research (phase 11 columns 6, 15 and 17). Infiltration rates of 3.5 mm and 5.0 mm were used to achieve HRTs of 120 and 200 days respectively. When the HRTs of the columns in this work shifted to 120 and 200 days from 35 days, methanogenesis slowed down compared to HRT of 35 (comparison of columns 7 and 8 and 2, 5 and 6 in Section 5.4). But in Rovers and Farquhar (1973) infiltration rate increased from 0 mm/day to 4 mm/day. This should favor methanogenesis. Therefore the failure of methanogenesis would not appear to be just due to reduction in HRT with rapid infiltration. It could be due to some other factor introduced with the cold water infiltration. Also it was observed in this research that the effects of HRT was dependent on the stage of the decomposition of the refuse mass. For example column 6 had very high gas production and its pH did not decrease when the HRT was increased as did its triplicate columns 15 and 17. The effect seen in Rovers and Farquhar's (1973) work could be due to the unestablished methanogenic population indicated by low CH<\ concentration. Leckie's study consisted of 5 landfill cells. Two of them had continuous water inflow and recirculation. These had higher methanogenesis than the other three. During the second winter high infiltration occurred through four of the columns. Columns with established methanogenesis kept increasing methane concentration. The control did not establish methanogenesis. When water infiltrated due to the cracks in the cover, organic carbon in leachate increased. The other two cells had some methane in the gas (5 - 10%). Chapter 5. Results and Discussion 194 After the increased water inflow, leachate organic carbon increased in both columns. Effect on CH4 concentration was different. One cell kept increasing CH4 concentration while the other decreased. The behavior of the cell with decreased CH4 concentration is similar to what happened in Rovers and Farquhar's (1973) work. Therefore it could be that unestablished methanogenesis was disturbed by the increased infiltration. Burns Bog landfill had established methanogenesis when the study started (Wreford, 1995). Methane concentration and methane production increased with rainfall. The same trend of increasing organic constituents was also observed at the Richmond landfill during high water input (application of dredge from the Fraser river) (Soper and McAlpine, 1977). At neither the Port Mann landfill (Jasper et al., 1987) nor Richmond landfill (Soper and McAlpine, 1977) were gas characteristics measured and hence one is unable to analyze the effect of HRT on overall methanogenesis. pH of initial leachate were between 5.2 and 5.5. With time increasing pH for high CH4 producing columns and decreasing pH for the other were observed. High Ci74 producing columns increased their pH irrespective of the change in HRT during phase II. When HRT was increased in low CH4 producing columns pH decreased until CH4 production was established, and then started to increase. Decreasing HRT of low CH4 producing columns increased the pH due to the dilution of VFAs. When HRT was decreased in the high gas producing columns with pH higher than 5.8, a slight decrease in pH was observed. With high infiltration through landfills, significant amount of CO2 dissolves in water. According to water chemistry, the pH should decrease. But in this work it was seen that columns that had higher VFAs, have increases in pH. This helps methanogenesis. Columns that had low VFA, high gas production and higher pH, decreased their pH and stabilized around a pH of 5.7. No detrimental effect on methanogenesis was observed due to decrease in pH. From Figure 5.87, it can be seen that lower HRTs due to higher infiltration, gives a pH close to 6 for a wide range of alkalinities. This is also a favorable Chapter 5. Results and Discussion 195 effect of low HRT on methanogenesis. Correlation analysis for zinc and iron for pH and methane production rates showed different correlations from column to column. Correlation of iron concentrations to pH and CH4 production was dependent on the changes in HRT and CH4 production stage of the columns. These correlations could be due to the coincidence of effects of HRT on iron concentrations. Therefore predictability of correlations in a different situation is question able. Correlation of zinc concentrations to pH and CH4 production was unpredictable. Increasing methane production increases pH which should decrease the solubility of met als. If increasing pH is always due to increasing methane production, combined effect should be predictable or the data should show the combined effect. But data analysis showed very different unpredictable correlations showing the complicated nature of the solubility of metals in the landfill ecosystem. Chapter 5. Results and Discussion 196 After 163 days of HRT=35 days HRT Changed to (day) Effect on pH Effect on Iron Correlations Cumulative CH4 production (L) pH 635.9 5.74 <—> increased either very little significant correlation to pH/Ci/4 production rate or were not significant 197.1. 5.39 <—• increased 172.7 5.52 *—• increased 30.1 4.99 <—• decreased 27.2 4.87 decreased until day 308* 194.8 5.46 |120 increased no significant correlation to pH and positive correlation to CH4 production rate 191.2 5.56 T120 increased 166.5 5.33 |120 increased 175.8 5.58 T200 increased 95.1 5.14 |200 decreased strong negative correlation to pH and strong positive correlation to CH4 production rate 33.6 5.14 T200 decreased 94.5 5.39 |60 decreased 76.3 5.4 |60 decreased until day 329* 66.6 5.46 T60 decreased until day 443* 66.0 5.33 118 decreased until day 308* very small or not significant correlation to pH and -ve correlation to CH4 production rate except one column 38.6 5.26 118 increased 31.5 5.33 118 decreased until day 266* Table 5.13: Effect of HRT on pH and Iron Concentrations;<—>=not changed, |= in creased, J.=decreased, *=then started to increase pH Chapter 5. Results and Discussion 197 After 163 HRT Effect on VFA, Alkalinity days of Changed COD, TOC, End of HRT=35 days to TS, Na Phase II summary Cumulative CH4 pH (day) and specific (mg/L as production (L) conductance CaCOz) 635.9 5.74 <—> 340 high CH4 prod. 197.1 5.39 <—• kept 495 and high HRT 172.7 5.52 <—> decreasing 460 maintained 30.1 4.99 <—• 135 high values; 27.2 4.87 <—• 205 high CH4 prod. 194.8 5.46 T120 770 and low HRT 191.2 5.56 T120 895 maintained 166.5 5.33 T120 increased 740 a medium range; 175.8 5.58 T200 for some 1060 low CH4 95.1 5.14 T200 time and 510 production 33.6 5.14 |200 then 695 low HRT had 94.5 5.39 T60 decreased 150x very low values; 76.3 5.4 T60 370 low CH4 66.6 5.46 T60 365 production and 66.0 5.33 118 kept 200 high HRT had 38.6 5.26 118 decreasing 165 medium values 31.5 5.33 118 160 Table 5.14: Effect of HRT on VFA, COD, TOC, TS, Na and Specific Conductance;^—>=not changed, T= increased, J.=decreased, x= had very low values from the begining Chapter 5. Results and Discussion 198 After 163 HRT days of Changed Effect HRT=35 day to Effect on on Zinc Cumulative CH4 pH (day) TKN and Concentrations production (L) NHZ - N 635.9 5.74 *—• 197.1 5.39 < • continuous 172.7 5.52 < • kept release was 30.1 4.99 * • decreasing observed 27.2 4.87 *—• 194.8 5.46 T120 kept decreasing showed 191.2 5.56 T120 increased for unpredictable 166.5 5.33 T120 some time correlations 175.8 5.58 T200 and then to pH and 95.1 5.14 T200 decreased methane 33.6 5.14 |200 production 94.5 5.39 T60 decreased in rate 76.3 5.4 T60 a reduced rate 66.6 5.46 T60 than before 66.0 5.33 118 38.6 5.26 118 kept decreasing 31.5 5.33 118 Table 5.15: Effect of HRT on TKN, NH3-N and Zinc;<—>=not changed, T= increased, j=decreased Chapter 5. Results and Discussion 199 5.11 Potential Applications of Findings As discussed in Section 2.5.8, researchers still debate the optimum moisture content for methanogenesis in landfills. From a microbial stand point, moisture content in the refuse is an important factor in landfill stabilization. It facilitates the hydrolysis process. Removal of VFAs produced by enhanced gas production will reduce the hydrogen partial pressure and reduce feedback inhibition of hydrolysis. This will also give higher CHA production which will make recovery of gas for energy more feasible. If the CH4 recovery is not intended, removal of VFAs by means of moisture movement (infiltration) will also enhance landfill stabilization. But an active population of methanogenic bacteria will keep the hydrogen partial pressure low enough for acetogenic bacteria, which convert other VFAs to acetic acid to be used by acedogenic bacteria. Infiltration also helps methanogenesis by means of providing the solution and transport of CC>2- Low C02 partial pressures enhance methanogenesis. This work showed that moisture availability higher than field capacity will help methanogenesis and stabilize the landfill faster. The problem of souring due to accumulation of acids has been observed in many research projects during the early stages of decomposition (for example, Barlaz et al. (1989), Fungaroli and Steiner, (1971)). Barlaz et al. (1990) discussed the importance of research to solve the problem of souring. Separation of food waste from the waste stream and composting them prior to landfilling was identified as a solution. This is a good method for future landfills. But for the existing landfills, lowering the HRT by increasing the infiltration can be used to solve the problem of souring as it will increase the pH and decrease the VFAs (column 11, 12 and 14 in phase II and columns 17, 13 and 1 in phase III). Most modern landfills are designed to prevent rainfall and ground water from enter ing the refuse mass. This creates a moisture deficient environment within the landfill Chapter 5. Results and Discussion 200 which will reduce landfill stabilization and prolong the time necessary to complete the stabilization of the landfill. According to Knox (1990) between 5 to 7 bed volumes (a bed volume is the total moisture content of the landfill, including absorbed water and free leachate) of water will have to pass through most landfills receiving degradable wastes to reduce NHz — N levels to dischargeable concentrations (to reduce NHz — TV concentra tions by three orders of magnitude within one generation). Calculation of flushing rates generated solely by percolation through clay caps have shown that it will easily take 500 years or more (Harris et al., 1994). This can not be considered sustainable. Six or more generations will have to lookout for our garbage. Landfill liners and leachate collection systems are designed for much shorter periods (30 - 40 years) than this. The potential for the failures in these structures pose a much greater risk to the ground and surface water than the generation, collection and treatment of leachate under controlled conditions. In the present work NHz-N concentration were below 10 mg N/L after passing of 5-10 L/kg dry refuse. Vancouver landfill at Burns Bog is used as an example to demonstrate this in a practical situation. It is assumed that all the rainfall water was allowed to infiltrate through the refuse and that there will be no waste deposited on top of this 8 hectare area. Calculation (Data were taken from Wreford, 1995 unless specified) Refuse deposited in the landfill during year 1992 471,000 tonnes MSW + 150000 tonnes DLC Area used to deposit waste for 3 years 300 m X 800 m Area used for one year 80000 m2 MSW field capacity (Munasinghe, this work) 69 % wet weight Chapter 5. Results and Discussion 201 Moisture at placement (Bird and Hale, 1976) = 24 % wet weight Additional moisture that can be absorbed 45 % wet weight Amount of moisture that can be absorbed to MSW= 471,000x1000x45 % kg = 21195xl04 kg = 211950 m3 The waste was spread over an area of 80000 m2 Infiltration required to reach the field capacity = 211950/80000 m = 2649 mm Annual rainfall for Vancouver landfill =1150 mm Evapotranspiration for the Burns Bog area = 639 mm Time needed to reach field capacity = 2649 mm/(1150-639) mm/year Evapotranspiration is high in dry months. Most of the rainfall is during the rest of the year. Therefore available water is higher than what is assumed above and the time taken to reach the field capacity is less than 5.2 years. For the landfill to bring JVi/3-N below 10 mg/L the refuse will need to pass 5 - 10 liters of water through each kg of dry refuse. Total weight of dry refuse deposited in year 1992 = 471,000 tonnes x 76% 5.2 years 357960 tonnes Total volume of water needed to pass through 357960 x 1000 x (5 to 10) liters (17898 to 35796) x 105 liters 1789800 to 3579600 m3 Chapter 5. Results and Discussion 202 Assuming the source of water is rain. This will fall over an area of 80,000 m2. Time taken to bring the NH2-~N to a level lower than 10 mg/L = (17898 to 35796)xl05m/(80,000x511 mm/year) = (22.372 to 44.745) m /511 mm/year = 44 to 88 years after reaching the field capacity Total time since 1992 = 49 to 93 years This shows that even if all the available rainfall was let to infiltrate through the refuse it will take 49 - 93 years to stabilize the landfill with respect to JVi73-N. By providing 2000 mm/year infiltration rate (discussed in next paragraph) this portion of the Vancouver landfill at Burns Bog (filled starting 1992 over three years) can be stabilized within 12 to 23 years. The above calculation did not include 150,000 tonnes of DLC waste. Including this waste will bring the time span close to Harris et al. (1994). According to Harris et al. (1994) to reduce N H3 — N levels to dischargeable concen trations within 30 years, the mean hydraulic retention time must be less than 5 years. And for it to be effective, passing water must be reasonably uniform, reaching the whole of the waste mass eliminating zones of 'dead volume'. Irrigation rates equivalent to 2000 mm/year or more will be needed at many landfills. Moisture in the refuse could be distributed unevenly due to channeling; observed by Zeiss and Major (1993) and Zeiss and Uguccioni (1995). Channeling is the vertical flow of liquid through pores with cross sectional areas which are substantially less than the cross section of the top layer of waste where infiltration occurs. According to Zeiss and Uguccioni (1995) low infiltration rates are less likely to lead to pronounced channeling than high rates, because slow application of water will allow more time for the sorption into the refuse. Also capillary action in the waste layer may redistribute moisture so that the matrix flow regime in the waste Chapter 5. Results and Discussion 203 layer may contribute more to the overall discharge. Irrigation rates of 2000 mm/year or more should be distributed throughout the year to reduce channeling and allow moisture to be distributed evenly within the refuse mass. Increasing moisture and moisture movement remains the most practicable method to promote stabilization and methanogenesis. Landfill operation practices like the addition of water for compacting the refuse increases moisture in the landfill. This is a good method of increasing moisture. As it does not give sufficient moisture it has to be supplemented with another source of moisture. Recycling of leachate is the most common method used to improve methanogenesis and stabilization. This also increases moisture and moisture movement. Nutrients will be retained in the landfill. Leachate recycling stabilizes landfills with respect to degradable organic compounds but increase in other inorganic compounds is observed over time. Increased inorganic compound concentrations could lead to toxic levels and completely inhibit microbial activities over time. Landfills cannot be considered completely stabilized until the pollution threat to ground and surface waters are completely eliminated. Soluble compounds in landfills should be converted to gaseous or liquid phase and transported away from the landfill so that these are not mobilized at a later date and pose a risk to the environment. Leachate recycling will not achieve this. Problems associated with leachate recycling such as odor and biological clogging of recharge wells which have forced abandonment and storage of leachate requiring leakage proof facilities has made it unattractive as an alternate method for increasing moisture and moisture movement. Leachate recycle involves pumping which adds to the cost of operation. With enhanced gas production this energy requirement could come from landfill gas. Even if all the problems associated with leachate recycle are overcome it does not bring the landfill releases to a level that will allow for uncontrolled release. Precipitation and moisture at placement are the main sources of moisture available Chapter 5. Results and Discussion 204 for landfills. The seasonal variation in precipitation can cause problems if uncontrolled infiltration through the refuse is allowed. In reference to the Pacific North West; 1. High precipitation season coincides with the colder season; cooling of the refuse mass could impede methanogenesis and therefore high organic carbon levels appear in leachate. 2. During warmer months there could be reduced infiltration through the refuse mass which in turn reduces nutrient transport, by-product removal etc.. This is the time during which higher stabilization could be achieved with warmer temperatures available. 3. Uncontrolled high infiltration will promote channeling of water through refuse leaving moisture deficient zones. Wall and Zeiss (1995) suggest an alternate approach for landfill design; addition of moisture to stabilize the landfill faster. But the questions "How much moisture should be applied?" and "How will it be done?" arise. From the work of Leckie et al. (1979) it was seen that continuous water infiltration enhances methanogenesis. This research supports the study by Leckie et al. (1979) in that continuous water infiltration enhances methanogenesis. Infiltration rates as high as 170 mm/day (column 18) can be applied to landfills while enhancing methanogenesis. But caution should be taken not to introduce cooling effects with the applied water and landfill operation should address the nutrient availability. Introducing oxygen with increased infiltration did not seem to have an effect on the results of these column experiments. The refuse columns were 1.4 m in height. Normal landfill heights are at least an order of magnitude more. Therefore, any oxygen that is introduced with increasing water inputs should be readily consumed by aerobic bacteria in the top most layers. Chapter 5. Results and Discussion 205 Decreasing HRT by increasing infiltration to enhance methanogenesis raise the con cerns about leachate treatment. With high infiltration one would expect high volumes of leachate to deal with. In most of the present landfills all the rain water that falls on the landfill premises is collected and treated before discharged. This rainfall gives peak flow rates during winter months. Decreasing HRT will not be economically feasible if importing water from other sources is intended. Decreasing HRT should be managed with the available water in the site in which case volume of leachate to be treated will be the same. Also peak flow rates will be damped out by passing through the refuse. Towards the end of the study period some of the columns showed a decreasing trend in CH4 production rates. Barlaz et al. (1989) also observed a decrease in CH4 pro duction in his cells with leachate recycle. They discounted absence of microorganisms, toxic carboxylic acids, and cation concentrations and an ammonia limitation. From this study it was also seen that toxic levels of carboxylic acids or cation concentrations were not the cause of the decrease in CH± production as they were low during the periods of decreased CH4 production. With time, available nutrients could become limiting for the biodegradation and hence decrease in gas production. But in this work TKN concentra tions towards the end showed that nitrogen could not be the limiting factor. Data showed that in higher HRT columns (15 and 17 in phase II) NHz — N increased for sometime indicating NH3 — N is released to the leachate faster than they are flushed out. In this research only after passing 5 - 10 L of water/kg dry refuse that NH2, — N were lower than 10 mg/L. Burns Bog landfill refuse will be 49 - 93 years old by the time refuse is flushed 5 - 10 L/kg dry refuse. Therefore, according to this research nitrogen was not limiting even with very low HRTs used. It could be that other necessary elements for biodegradation are beginning to deplete. If this is what is happening in low gas producing columns, there is organic carbon left that will not be degraded. This is a disadvantage when recovery of gas for energy is intended since the potential for gas production is lost. Also after Chapter 5. Results and Discussion 206 the gas production becomes very low, the diffusion of atmospheric air will create aerobic conditions further slowing the process. These observations show the importance of initiation of high gas production early in landfills. By providing moderate infiltration rates, nutrients would be retained within the landfill (compared to the high infiltration rates) while landfill stabilization is enhanced. In this work even with high flushing rates used TKN concentrations showed that nitrogen could not be limiting. Landfill management strategy should be carefully analyzed. If the landfill is to receive fresh refuse in layers over the years, it is unlikely to be deficient in nutrient or other necessary elements even if high infiltration rates are applied. In this case providing infiltration will carry the organic carbon from top layers to the layers at the bottom where methanogenesis is well established. According to Barlaz et al. (1989) polymer hydrolysis limited the refuse methanogen esis. In this work even though the CH4 production rates were decreasing they were still much higher than that reported for landfill. If the decreasing CH± production rates are due to the limiting hydrolysis, improving hydrolysis at this decelerated methane phase should be considered to stabilize the landfill faster. Starting leachate recycling at this stage could be an option which will provide lechate treatment as well as extra organics for the methanogenic population. The discussion in the Section 5.9 shows that carbon released from the landfill is highly dependent on the gas production of the system, i.e. an active microbial population is necessary for the stabilization of a landfill with respect to organic carbon. Higher gas producing columns released 50% more carbon to the environment than the low gas producing columns. If the low carbon release from the low gas producing columns is due to depletion of necessary elements for biodegradation, low gas producing columns will give a lower CH4 yield than high gas producing columns. This is disadvantageous when the recovery of gas for energy is intended, since the potential for gas production is lost. It Chapter 5. Results and Discussion 207 was also seen in this work that only 3% to 16% of the methane potential was recovered. By the end of the study period even though CH4 production rates were decreasing they were still high. Hydrolysis of cellulose would not have been completed. Most of the methane potential from cellulose and hemicellulose was not recovered. Implications of these in the real landfills would be that landfill gas recovery projects will not be as economically viable as they could be. Since the majority of the methane potential in a landfill is from cellulose and hemicellulose it is necessary to concentrate on hydrolysis process in the landfill. Therefore it is important to plan the landfill operation with the application of enhancement technology if the recovery of gas is intended. Also, the results of this study showed high CH4 production columns behave favor ably. For example, column 6 had high CH4 production; when the HRT was increased in phase II, column 6 behaved differently than other two columns 15 and 17 (low CH4 pro duction) that assumed the same HRT. Column 6 increased its pH which is favorable for methanogenesis, where as columns 15 and 17 decreased their pH. High CH4 production columns could maintain a higher alkalinity irrespective of HRT. Enhancement of landfill stabilization should concentrate on establishing a healthy microbial population at the very beginning. This will give faster stabilization, as well as a system that is not prone to failures due to unavoidable natural causes. The objective of this research was to see the effects of HRT on landfill leachate and gas characteristics. Although much effort went into creating 18 identical columns of landfill, decomposition in most columns was highly variable with a few exceptions. Some possible causes for the differences were explained in Section 5.3. These columns were carefully controlled to have identical enhanced methanogenesis. Addition of anaerobic digestor sludge must have helped in establishing methane production at the very beginning in the majority of the columns. But the extent of methanogenic activity was different from column to column. Barlaz et al. (1987) also found that it was difficult to duplicate Chapter 5. Results and Discussion 208 methane production in replicate containers. This variability questions the ability and reliability of control or enhancement of methanogenesis in real landfills where conditions are far from the ideal laboratory conditions. Chapter 6 Conclusions and Future Work 6.1 Conclusions HRT of landfills affects landfill gas and leachate characteristics. Based on the results of this research, the following conclusions can be made: 1. For unsaturated landfills: S HRT = — Q Where; S = Volumetric water holding capacity of the solid waste in the landfill X Volume of the solid waste in the landfill (L3) Q = Flow rate through the landfill (L3r_1) 2. Tracer work also showed that as the refuse undergoes decomposition, HRT decreases. This is reflected in the equation above since the water holding capacity (S) decreases with the decomposition of the refuse. 3. Percent CH4 concentration in gas decreases with increasing HRT up to 60 days. 4. Percent CH4 concentration in gas did not show any significant effect from increasing HRT beyond 60 days 209 Chapter 6. Conclusions and Future Work 210 5. Lower HRTs result in higher CH4 concentration in the landfill gas due to the following reasons; (1) dissolution of C02 into the increased leachate flow and (2) Enhanced methanogenesis with the decrease in C02 partial pressure. 6. Comparison of CH4 production of columns with similar decomposition history showed lower HRTs resulted in higher CH4 production than the higher HRTs. 7. The amount of carbon released (both in gas and leachate) to the environment is highly dependent on gas production. High gas producing columns released 50% more carbon than low gas producing columns giving a more stabilized landfill with respect to carbon. 8. Gas production itself helps in developing favorable conditions for biological degradation; it increases pH, produces alkalinity when VFAs are consumed, responds favorably to changes in HRT, and reduces inhibitive concentrations of VFAs. 9. The initial leachate pH was between 5.2 and 5.5. During phase I, high gas producing columns increased their pH, while low gas producing columns de creased their pH. High gas producing columns increased their pH irrespective of the change in HRT in phase II. A decrease in HRT helped low gas produc ing columns to increase their pH which is favorable for methanogenesis. A decrease in HRT during phase III for high gas producing columns decreased pH but no detrimental effect on gas production was observed. 10. Correlation of iron concentrations to pH and CH4 production showed depen dence on HRT and CH4 production stage of the columns. 11. Zinc concentrations showed unpredictable correlations to pH and methane production rate. Chapter 6. Conclusions and Future Work 211 12. The high organic carbon concentrations observed in field studies are not, based on this study likely to be due to the failure of methanogenesis because of high water inputs. 1 6.2 Recommendations for Future Work 1. In this research HRT was changed by changing the infiltration rate. The effect of HRT when changed due to the height of refuse, saturated and unsaturated depths of refuse and the density should be studied. This will help determine the most effective landfill designs to enhance methanogenesis. 2. Increase in organic carbon observed in field studies could be due to the failure of methanogenesis as a result of the cooling effects introduced by infiltrating water. Studies that characterizes leachate and gas with respect to temperature of infiltrating water with different HRTs is necessary. 3. The concept of microenvironment needs further investigation; spacial distri bution of microbial species and other relevant information. 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Mitchell, (ed.), John Wiley, New York, vol.2, pp. 349-376. [75] Zeiss, C. and W. Major (1993), "Moisture Flow Through Municipal Solid Waste: Patterns and Characteristics", Journal of Environmental Systems, Vol. 22 (3), pp 211-231. [76] Zeiss, C. and M. Uguccioni (1995), "Mechanisms and Patterns of Leachate Flow in Municipal Solid Waste Landfills", Journal of Environmental Systems, Vol. 23 (3), pp 247-270. Appendix A Calculation of COi produced and Total Gas Production When microbes produce CO2 they excrete it in dissolved form. Outside the microbial cell, infiltrating water provide the media for carrying dissolved carbon dioxide. When carbon dioxide dissolves in water it forms a weak acid, carbonic acid (H2CO3), which dissociates to give bicarbonate and carbonate ions. Only a small fraction of dissolved CO2 forms carbonic acid and, depending on pH, four forms can be present, namely, CO2, H2CO3, HCO3 , and CO3 . Dehydration of CO2 will release CO2 as gas. It can be seen from the calculated gas productions in Sections A. 1.3 (method 1) and A.1.6 (method 2), 14529 ml/day and 8819 ml/day respectively are much higher than measured gas production 3282 ml/day. Methane production for this day is 2373 ml/day. This gives CO2 productions of 12156 ml/day 6446 ml/day for method 1 and method 2 respectively. This is not close to the methane production, which is expected when methanogenesis is established. These errors could be due to the following discussed. According to Covington (1985) hydration and dehydration of CO2 is surprisingly slow. In the landfill lysimeters with the contact time available it is very unlikely that equilib rium conditions were achieved before leaving the lysimeters. Therefore use of Henry's law for calculating CO2 dissolved could be erroneous. But it was assumed otherwise. Also all the other equations used in the calculations assumes the equilibrium conditions of the system. Leachate leaving the lysimeters would not have achieved the equilibrium by the time pH and alkalinity were measured. Therefore the errors in assuming equilibrium conditions is larger for low HRTs. This can be seen from the Figures A.l to A.8. The 219 Appendix A. Calculation of CO2 produced and Total Gas Production 220 difference between measured and calculated are higher for low HRT. Both methods used assume that the alkalinity is only due to bicarbonates. For the period in method 1 this assumption should give little errors. But for the period when leachate was stronger this could give larger errors. It can be seen that the calculated carbon dioxide produced is far from the real carbon dioxide produced. Therefore calculated gas production was not used in any of the data analysis. A.l C02 Produced Carbon dioxide dissolved in the leachate were estimated using two methods and are presented in Sections A.1.1 and A.1.4. A.1.1 For Samples with Low Dissolved Solids - Method 1 When the total alkalinity of a water is due almost entirely to hydroxides, carbonates, or bicarbonates, and the total dissolved solids is not greater than 500 mg/L, alkalinity forms, free CO2 and total CO2 can be calculated from the Equations A.6, A.7, A.8, A.9 and A.10 (Standard Methods (A.P.H.A. et al., 1992)). Since the dissolved solids in most samples were higher than 500 mg/L, this method was used only for columns 1, 2, 3, 4, 12, 14, 16 and 18 for the last few sampling days where dissolved solids were less than 500 mg/L. Calculated gas productions for those sampling days are shown in Figures A.l - A.8. Bicarbonate alkalinity as mg CaCOz/L = T - 5.0X10(pi/-10) 1 -f0.94X10(^-10) (A.6) Where; T= total alkalinity, mg CaCOz/L Appendix A. Calculation of CO2 produced and Total Gas Production 221 Carbonate alkalinity as mg CaC03/L = 0.94XBXlO(pH~10) (A.7) Where; B = bicarbonate alkalinity, from Equation A.6 Hydroxide alkalinity as mg CaCOz/L = 5.0X10(pi;r~10) (A.8) Free carbon dioxide mg C02/L = 2.0XBX10(e~pH) (A.9) Where; B = bicarbonate alkalinity, from Equation A.6 Total carbon dioxide rag C02/L = A + 0.44(25 + C) (A. 10) Where; A = mg free C02/L B = bicarbonate alkalinity, from Equation A.6 C = carbonate alkalinity, from Equation A.7 Note: Since pH in all the samples during the experiments were well below 8.3 total alkalinity was assumed to be equal to bicarbonate alkalinity. A. 1.2 Sample calculation For column 16, day 406; Appendix A. Calculation of C02 produced and Total Gas Production 222 = 1512 mg as CaC03/L = 3282 ml/day total alkalinity 1512 as mg CaCOz/L 2 X B X 10(6"pi/) mg CO2/L 2 X 1512 X lO"011 mg C02/L 2347 mg C02/L pH = 6.11, Alkalinity Flow rate = 5.6 L/day, Gas measured Bicarbonate alkalinity (B) = From Equation A.9 Free C02 (A) From Equation A. 10 Total C02 Equivalent C02 volume (ml) = Total C02 dissolved A + 0.44 (2B + C) mg C02/L 2347 + 0.44 (2 X 1512) mg C702/L 3678 mg CO2/L =*P X Flow rate^X °-^^X 3678 X 5.6 X 24.026/44 11247 ml/day A. 1.3 Total Gas Produced Calculated from Method 1 Total gas produced = Gas measured + C02 dissolved = 3282 + 11247 ml/day = 14529 ml/day Appendix A. Calculation of CO2 produced and Total Gas Production A. 1.4 For Samples with High Dissolved Solids - Method 2 In pure water at great dilution, the first dissociation; H2COZ ^ H+ + HC03 CH+XCHCO-Ki = CH2CO3 Second dissociation; HC03 ^ H+ + COf~ CH+X Cnn2-K2= C°3 CHCOJ For not pure water (sea water, leachate, wastewater) aH+XaHCO-K2 = 0-H2CO3 aH+Xaco2-AHCO^ Where a is the activity. Apparent dissociation constants; AH+XCHCO-*2 = aH+XCC02-O-H2CO3 — o-co2 X an2o aco2 = Pco2 X aQ Pco2 — Partial pressure of C02 aa = Solubility of C02 in pure water in moles per liter Appendix A. Calculation of C02 produced and Total Gas Production 224 ajj2o is unity for pure water and is depressed by the presence of salts in solution. In these calculations au2o is assumed to be unity. Pco2 X a0XaH20 Carbonate alkalinity = CHCO~ + 2CCQ2-K'* = r 3 (A.18) Total CO2 — CHCO- + CCQ2- A- Cco2 m solution Cco2 = asXPco2 as = solubility of C02 in leachate at 1 atm in moles per liter For the pH range in the samples CC02- could be assumed negligible. Also it was assumed that Alkalinity measured is only due to bicarbonates. But this is not really true for the initial leachate. Therefore calculated CO2 produced for the phase I should not be taken as accurate. A. 1.5 Sample Calculation For column 16, day 406; pH = 6.11, Alkalinity = 1512 mg as CaC03/L Flow rate = 5.6 L/day, Gas measured = 3282 ml/day Bicarbonate alkalinity (B) = total alkalinity = 1512 as mg CaC03/L Appendix A. Calculation of CO2 produced and Total Gas Production 225 Total C02 From Table 23 in Harvey (1963); PcOn CHCO~ Total CO2 1512/50000 mol./L ^HCO^ +" Ccoi m solution 0.0394 mol./L 0.277 atmospheres 1512/50000 mol./L 1512/50000 + 0.0394 X 0.277 mol./L 0.0412 mol./L Equivalent CO2 volume (ml) Total CO2 dissolved 0.0412^ X Flow rate ^X 0.082^ X 5.537 L/day 5537 ml/day A.1.6 Total Gas Produced Calculated from Method 2 Total gas produced = Gas measured -f CO2 dissolved - 3282 + 5537 ml/day = 8819 ml/day Appendix A. Calculation of CO2 produced and Total Gas Production 226 16000 ^ 14000 + P 12000 4-10000 c o o "O O a o ® 2000 • measured • method 1 • method 2 100 200 300 Time(day) 400 500 600 Figure A.l: Comparison of Measured and Calculated Gas Production Rates for Column 1 100 200 300 Time(day) 400 500 600 Figure A.2: Comparison of Measured and Calculated Gas Production Rates for Column 2 Appendix A. Calculation of CO2 produced and Total Gas Production 227 9000 -r Phase 100 200 300 Time(day) 400 500 600 Figure A.3: Comparison of Measured and Calculated Gas Production Rates for Column 3 600 Time(day) Figure A.4: Comparison of Measured and Calculated Gas Production Rates for Column 4 Appendix A. Calculation of CO2 produced and Total Gas Production 228 9000 -r Phase 100 200 300 Time(day) 400 500 600 Figure A.5: Comparison of Measured and Calculated Gas Production Rates for Col umn 12 Figure A.6: Comparison of Measured and Calculated Gas Production Rates for Col umn 14 Appendix A. Calculation oiCOi produced and Total Gas Production 229 16000 T 14000 + o 12000 "D e 10000 4-£ 8000 6000 4000 2000 + • measured • method 1 • method 2 Phase 100 200 300 Time(day) 400 500 600 Figure A.7: Comparison of Measured and Calculated Gas Production Rates for Col umn 16 50000 45000 S! 40000 D 5 35000 30000 £ 25000 •D 20000 O Q- 15000 O 10000 5000 measured method 1 method 2 100 200 Phase 300 Time(day) 400 500 600 Figure A.8: Comparison of Measured and Calculated Gas Production Rates for Col umn 18 Appendix B Regression Plots for Iron and pH 20 + + 4.6 4.8 5 PH 5.2 5.4 5.6 120 -r 100 80 •&> & 60 C 2 40 --20 --0 Figure B.9: Iron Vs pH for Column 1 y = -11.4 x + 140 SSE = 2395 F = 3.55, n = 21 Not significant 5.2 5.4 5.6 PH 5.8 —r— 6.2 6.4 Figure B.10: Iron Vs pH for Column 2 6.6 230 Appendix B. Regression Plots for Iron and pH Figure B.12: Iron Vs pH for Column 4 Appendix B. Regression Plots for Iron and pH 232 160 140 120 + _ 100 _i 80 c 2 - 60 40 + 20 0 o o 5.2 o o v y = 19.9 x -7.9 + 5.4 —I 5.6 5.8 PH 6.2 SSE = 22077 F=0.71, n = 21 Not significant 6.4 6.6 Figure B.13: Iron Vs pH for Column 5 250 -r 200 4-^ 150 + "&> E, c 2 100 4-50 y = 42.2 X - 122.8 Not significant —I 5.5 6.5 SSE = 50178 F=2.65, n = 21 PH Figure B.14: Iron Vs pH for Column 6 Appendix B. Regression Plots for Iron and pH Figure B.15: Iron Vs pH for Column 7 140 120 --100 -80 --40 -20 --0 5.2 * o o 5.4 5.6 y = -11.7 x + 149.9 SSE = 14121 F=0.47, n = 21 Not significant 5.8 6.2 6.4 6.6 PH 6.8 Figure B.16: Iron Vs pH for Column 8 Appendix B. Regression Plots for Iron and pH 234 Figure B.17: Iron Vs pH for Column 9 y = 14.8x-1.15 SSE = 5601 F=1.45, n = 21 Not significant 100 + 80 20 + 4.6 4.8 5 5.2 5.4 5.6 PH Figure B.18: Iron Vs pH for Column 10 Appendix B. Regression Plots for Iron and pH Figure B.20: Iron Vs pH for Column 12 Appendix B. Regression Plots for Iron and pH 236 Figure B.21: Iron Vs pH for Column 13 ~5> E 140 T 120 --100 80 p 60 40 --20 -0 o o 5.2 5.4 5.6 5.8 PH y = -21 x +162.7 SSE = 16125 F=1.1 n = 21 Not significant 6.2 6.4 Figure B.22: Iron Vs pH for Column 14 Appendix B. Regression Plots for Iron and pH 237 o -I 1 1 1 1 1 4 5 4.7 4.9 5.1 5.3 5.5 PH Figure B.23: Iron Vs pH for Column 15 200 i y = - 36.2 x + 304.2 180 -R =-0.46 160 - SSE = 20518 140 - F=5.2 n = 21 120 - Significant £ 100 - o o o ° I 80 < k o o o o 60 -40 - o 20 -0 - 1 —\ —I 1 I —I 1 1 5.3 5.5 5.7 5.9 6.1 6.3 6.5 6.7 PH Figure B.24: Iron Vs pH for Column 16 Appendix B. Regression Plots for Iron and pH 238 Figure B.25: Iron Vs pH for Column 17 5.3 5.5 5.7 5.9 PH 6.1 y = -20.5x + 164.8 SSE = 9530 F = 3.4 n = 21 Not significant 6.3 6.5 6.7 Figure B.26: Iron Vs pH for Column 18 Appendix C Regression Plots for Iron and Methane Production Rate E, c o 120 100 80 60 40 20 0 F = 37.8 n=22 Significant y = 0.017x +47.19 R = + 0.81 SSE = 3241 + 500 1000 1500 2000 2500 CH-4 Production (ml/day) 3000 3500 Figure C.27: Iron Vs Methane Production Rate for Column 1 120 100 1 80 E, 60 c 2 40 20 0 F = 2.1 n=21 Not significant + y = -0.001 x+ 79.57 SSE = 2653 1 h 2000 4000 6000 8000 CH-4 Production (ml/day) 10000 12000 Figure C.28: Iron Vs Methane Production Rate for Column 2 239 Appendix C. Regression Plots for Iron and Methane Production Rate 240 Figure C.29: Iron Vs Methane Production Rate for Column 3 Significant y = 0.01x +98.65 R = + 0.49 SSE = 14890 500 1000 1500 2000 2500 CH-4 Production (ml/day) 3000 3500 4000 Figure C.30: Iron Vs Methane Production Rate for Column 4 Appendix C. Regression Plots for Iron and Methane Production Rate Figure C.31: Iron Vs Methane Production Rate for Column 5 Figure C.32: Iron Vs Methane Production Rate for Column 6 Appendix C. Regression Plots for Iron and Methane Production Rate 242 20 --0 -I 1 1 1 1 1 0 2000 4000 6000 8000 10000 CH-4 Production (ml/day) Figure C.33: Iron Vs Methane Production Rate for Column 7 Figure C.34: Iron Vs Methane Production Rate for Column 8 Appendix C. Regression Plots for Iron and Methane Production Rate 243 180 T 160 --140 --_ 120 ^ 100 + | 80 + 60 40 + 20 0 _2_ O O * o F=0.13 n=23 Not significant + + + y= 0.002X +93.27 SSE = 22555 H 1 1 0 500 1000 1500 2000 2500 3000 CH-4 Production (ml/day) 3500 4000 Figure C.35: Iron Vs Methane Production Rate for Column 9 Figure C.36: Iron Vs Methane Production Rate for Column 10 endix C. Regression Plots for Iron and Methane Production Rate 160 140 120 100 "&> E, 80 c o 60 40 20 0 F = 7.4 n=23 Significant + + + 500 1000 1500 2000 CH-4 Production (ml/day) 2500 3000 Figure C.37: Iron Vs Methane Production Rate for Column 11 Figure C.38: Iron Vs Methane Production Rate for Column 12 Appendix C. Regression Plots for Iron and Methane Production Rate 245 200 180 • 160 :: 140 120 80 60 + 40 20 4-0 F = 3.0 n=23 Not significant y = -0.012x +121.18 SSE = 8239 + + 500 1000 1500 CH-4 Production (ml/day) 2000 2500 Figure C.39: Iron Vs Methane Production Rate for Column 13 Figure C.40: Iron Vs Methane Production Rate for Column 14 Appendix C. Regression Plots for Iron and Methane Production Rate 246 300 250 200 c» £ 150 c s 100 50 y = 0.077x + 17.11 R = + 0.78 SSE = 72520 F = 33.4 n=23 Significant o o 0 4-500 1000 1500 2000 2500 CH-4 Production (ml/day) 3000 3500 Figure C.41: Iron Vs Methane Production Rate for Column 15 y = -0.013x + 151.29 R = - 0.47 SSE = 20841 F = 6.0 n=23 Significant o o + + + + 1000 2000 3000 4000 5000 CH-4 Production (ml/day) 6000 7000 Figure C.42: Iron Vs Methane Production Rate for Column 16 Appendix C. Regression Plots for Iron and Methane Production Rate 247 y =0.086x + 33.33 Significant 0 A 1 1 1 1 1 1 1 0 200 400 600 800 1000 1200 1400 CH-4 Production (ml/day) Figure C.43: Iron Vs Methane Production Rate for Column 17 140 120 100 2 80 | 60 40 oo °oo y = -0.01x + 69.68 R = - 0.64 SSE = 6861 F = 14.23 n=23 Significant 20 4-4- + 1000 2000 3000 CH-4 Production (ml/day) 4000 5000 Figure C.44: Iron Vs Methane Production Rate for Column 18 Appendix D Regression Plots for Zinc and pH 1.4 j 1.2 --1 --0.8 --E, o c 0.6 --N 0.4 --0.2 --0 --4.6 4.8 5 PH 5.2 o o y = -0.023x + 0.819 SSE = 1.1 F = 0.02 n = 22 Not significant <x> 5.4 5.6 248 Appendix D. Regression Plots for Zinc and pH 249 Figure D.48: Zinc Vs pH for Column 4 Appendix D. Regression Plots for Zinc and pH 250 1.4 1.2 1 i>8 5 0.6 + N y = - 0.32x + 2.18 R =-0.47 SSE = 1.1 F = 5.7 n = 22 Significant Figure D.49: Zinc Vs pH for Column 5 12 ~r 10 + 05 £ 6 + o c N y = - 1.84X+ 12.19 SSE = 83.6 F = 3.88 n = 22 Not significant 5.5 pH 6.5 Figure D.50: Zinc Vs pH for Column 6 Appendix D. Regression Plots for Zinc and pH 251 Figure D.52: Zinc Vs pH for Column 8 Appendix D. Regression Plots for Zinc and pH 252 y = - 1.98X + 13.39 SSE = 68.5 F = 4.3 n = 22 Not significant 4.5 T 4 3.5 -3 --rib 2.5 E, ¥ 2 + Kl 1.5 1 0.5 + 0 4.6 Figure D.53: Zinc Vs pH for Column 9 °o + y = 1.8x-6.53 R = + 0.47 4.7 4.8 4.9 5 pH 5.1 —t— 5.2 —I— 5.3 SSE = 28.1 F = 5.8 n = 22 Significant 5.4 5.5 Figure D.54: Zinc Vs pH for Column 10 Appendix D. Regression Plots for Zinc and pH 253 1.8 T 1.6 1.4 1.2 4-1 + g 0.8 N y = 0.39x-1.54 SSE = 2.8 F= 1.14 n = 22 Not significant o o 3.5 -r 3 --2.5 -5* 2 -E i^.5--N 1 --0.5 --0 -Figure D.55: Zinc Vs pH for Column 11 4.7 4.9 5.1 o<>< —f— 5.3 PH 5.5 5.7 y = - 0.21x + 2.54 SSE = 15.6 F = 0.14 n = 22 Not significant 5.9 6.1 Figure D.56: Zinc Vs pH for Column 12 Appendix D. Regression Plots for Zinc and pH 254 Figure D.57: Zinc Vs pH for Column 13 0.9 -| 0.8 - O y = -0.21x + 1.44 0.7 - SSE = 0.9 0.6 - F = 2.56 n = 22 "cn 0.5 - Not significant E, ¥o.4 -N o 0.3 - —-—•— ° 0.2 - • oo 0.1 - o o o o —— o • ^_>> o 0 - 1 1 1 —I O—I 1 1 5 5.2 5.4 5.6 5.8 6 6.2 6.4 Figure D.58: Zinc Vs pH for Column 14 Appendix D. Regression Plots for Zinc and pH 25 20 4-•~ 15 + "o> E, o R 10 4-5 + 25 -r 20 y = -2.23x +16.23 SSE = 440 F = 0.38 n = 22 Not significant o-° o <*> o o o ° 1 1 1 1 1 1 1 1 1 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 pH Figure D.59: Zinc Vs pH for Column 15 y = + 0.54X + 1.85 SSE = 447.3 Not significant F = 0.05 n = 22 IT 15 Oi E, o H 10 4- ' <0 o o o o° v<> o o <> o o o 4 1 h 5.2 5.4 5.6 5.8 6 6.2 6.4 6.6 6.8 PH Figure D.60: Zinc Vs pH for Column 16 Appendix D. Regression Plots for Zinc and pH 256 Figure D.61: Zinc Vs pH for Column 17 Figure D.62: Zinc Vs pH for Column 18 Appendix E Regression Plots for Zinc and Methane Production Rate 1.40 -r 1.20 _ 1.00 rr |> 0.80 4-"g 0.60 N 0.40 0.20 4-0.00 o o o o o + 4-y = - 5.3E-6X + .72 Not significant SSE = 1.15 F = 0.01 n=24 o 4-500 1000 1500 2000 2500 , CH-4 Production (ml/day) 3000 3500 Figure E.63: Zinc Vs Methane Production Rate for Column 1 1.20 1.00 0.80 •B 0.60 o c N 0.40 0.20 E y = - 6E-5x + 0.51 R = - 0.73 SSE = 0.65 F = 22.3 n=22 Significant 0 2000 4000 6000 8000 10000 12000 CH-4 Production (ml/day) Figure E.64: Zinc Vs Methane Production Rate for Column 2 257 Appendix E. Regression Plots for Zinc and Methane Production Rate 258 Figure E.65: Zinc Vs Methane Production Rate for Column 3 8.00 7.00 6.00 ^ 5.00 4.00 y = -0.00059X + 2.98 R = - 0.49 SSE = 46.99 F = 7.18 n=24 Significant 0 500 1000 1500 2000 2500 3000 3500 4000 CH-4 Production (ml/day) Figure E.66: Zinc Vs Methane Production Rate for Column 4 Appendix E. Regression Plots for Zinc and Methane Production Rate 259 1.40 T 1.20 1.00 + o) 0.80 E + o y = -7.2E-5X + 0.57 R = - 0.58 SSE = 0.95 F = 11.33 n=24 Significant 0 1000 2000 3000 4000 5000 6000 7000 8000 CH-4 Production (ml/day) Figure E.67: Zinc Vs Methane Production Rate for Column 5 12.00 -r 10.00 8.00 rr £ 6.00 o c N 4.00 2.00 y = -0.00043X + 2.82 R = - 0.41 SSE = 83.58 F = 4.5 n=24 Significant 1000 2000 3000 4000 5000 CH-4 Production (ml/day) 6000 7000 Figure E.68: Zinc Vs Methane Production Rate for Column 6 Appendix E. Regression Plots for Zinc and Methane Production Rate y = -2.3E-5X + 0.21 R = - 0.53 SSE = 0.26 F = 8.1 n=23 Significant 2000 4000 6000 CH-4 Production (ml/day) 8000 10000 Figure E.69: Zinc Vs Methane Production Rate for Column 7 Figure E.70: Zinc Vs Methane Production Rate for Column 8 Appendix E. Regression Plots for Zinc and Methane Production Rate 261 y = -0.0012x+ 4.76 R = - 0.63 SSE = 50.6 500 1000 1500 2000 2500 3000 3500 4000 CH-4 Production (ml/day) Figure E.71: Zinc Vs Methane Production Rate for Column 9 Figure E.72: Zinc Vs Methane Production Rate for Column 10 Appendix E. Regression Plots for Zinc and Methane Production Rate 262 y = -0.00018x+ 0.73 R = - 0.45 SSE = 2.36 F = 5.72 n=24 Significant 500 1000 1500 2000 CH-4 Production (ml/day) 2500 3000 Figure E.73: Zinc Vs Methane Production Rate for Column 11 Figure E.74: Zinc Vs Methane Production Rate for Column 12 Appendix E. Regression Plots for Zinc and Methane Production Rate 263 Figure E.75: Zinc Vs Methane Production Rate for Column 13 Figure E.76: Zinc Vs Methane Production Rate for Column 14 Appendix E. Regression Plots for Zinc and Methane Production Rate 264 25.00 20.00 1J 15.00 + cn E, o R 10.00 5.00 + 0.00 y = - 0.00034X + 5.55 SSE = 449 F = 0.12 n=24 Not significant o o oo -35-O « 0$ o o + + + 500 1000 1500 2000 2500 3000 3500 CH-4 Production (ml/day) Figure E.77: Zinc Vs Methane Production Rate for Column 15 25.00 T 20.00 =d 15.00 cn | 10.00 + y =-0.00147x+ 11.72 R = - 0.44 SSE = 363.2 F = 5.34 n=24 Significant 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 CH-4 Production (ml/day) Figure E.78: Zinc Vs Methane Production Rate for Column 16 Appendix E. Regression Plots for Zinc and Methane Production Rate 265 3.00 j 2.50 --2.00 --Oi £ 1.50 o c N 1.00 4-0.50 0.00 y = 0.000162x + 1.48 + + SSE = 3.4 F = 0.9 n=24 Not significant H 1 200 400 600 800 1000 CH-4 Production (ml/day) 1200 1400 Figure E.79: Zinc Vs Methane Production Rate for Column 17 Figure E.80: Zinc Vs Methane Production Rate for Column 18 Appendix F Leachate Characteristics Data F.l pH Leachate pH Column # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Date Time (day) 6/10/93 0 5.48 5.41 5.49 5.46 5.41 5.39 5.51 5.54 5.47 5.43 5.49 5.49 5.48 5.52 5.27 5.42 5.35 5.45 20/10/93 14 5.46 5.47 5.50 5.43 5.48 5.45 5.60 5.52 5.49 5.43 5.53 5.52 5.47 5.46 5.24 5.41 5.30 5.45 17/11/93 42 5.47 5.55 5.70 5.49 5.47 5.50 5.63 5.63 5.53 5.43 5.51 5.56 5.43 5.40 5.31 5.40 5.28 5.32 1/12/93 56 5.52 5.50 5.65 5.47 5.48 5.55 5.65 5.53 5.51 5.43 5.56 5.52 5.41 5.39 5.29 5.39 5.33 5.46 15/12/93 70 5.58 5.54 5.66 5.53 5.53 5.63 5.70 5.59 5.55 5.46 5.58 5.59 5.46 5.43 5.36 5.41 5.42 5.49 29/12/93 84 5.51 5.50 5.63 5.49 5.44 5.60 5.59 5.51 5.37 5.38 5.48 5.43 5.37 5.30 5.32 5.34 5.39 5.48 12/1/94 98 5.57 5.51 5.65 5.60 5.51 5.72 5.56 5.55 5.44 5.29 5.60 5.56 5.31 5.40 5.34 5.43 5.46 5.44 26/1/94 112 5.43 5.29 5.50 5.45 5.40 5.61 5.41 5.43 5.34 4.98 5.45 5.44 5.19 5.28 5.22 5.30 5.28 5.33 2/9/94 126 5.46 5.36 5.58 5.46 5.54 5.68 5.51 5.51 5.41 5.00 5.49 5.50 5.18 5.39 5.29 5.60 5.35 5.48 2/23/94 140 5.36 5.16 5.42 5.32 5.37 5.53 5.33 5.38 5.26 4.76 5.29 5.30 4.89 5.18 5.07 5.51 5.09 5.33 3/9/94 154 5.39 5.23 5.46 5.40 5.56 5.58 5.39 5.46 5.33 4.87 5.33 5.33 4.99 5.26 5.14 5.74 5.14 5.52 3/23/94 168 5.22 5.21 5.39 5.38 5.37 5.52 5.27 5.38 5.21 4.72 5.15 5.08 4.81 5.17 5.03 5.90 5.01 5.64 4/6/94 182 5.21 5.28 5.38 5.36 5.40 5.52 5.41 5.44 5.30 4.90 5.35 5.10 4.90 5.32 5.08 6.00 5.13 5.74 4/20/94 196 5.05 5.30 5.34 5.27 5.30 5.39 5.49 5.39 5.14 4.77 5.18 4.92 4.79 5.21 5.03 6.20 5.02 6.03 5/4/94 210 5.02 5.33 5.38 5.22 5.37 5.40 5.81 5.41 5.14 4.75 5.18 4.88 4.76 5.25 4.96 6.33 5.00 6.32 6/8/94 245 5.01 5.73 5.36 5.13 5.82 5.57 6.25 5.41 5.27 4.74 5.08 4.80 4.75 5.34 4.87 6.37 4.99 6.43 6/29/94 266 4.71 6.03 5.22 4.96 5.49 5.66 6.37 5.29 5.24 4.66 5.04 4.78 4.66 5.56 4.70 6.47 4.85 6.31 8/10/94 308 4.70 6.46 5.19 4.93 5.42 6.09 6.70 5.54 5.55 4.67 4.90 4.86 4.71 6.39 4.65 6.38 4.83 6.45 8/31/94 329 4.68 6.33 5.16 4.92 5.80 6.40 6.48 6.00 6.02 4.70 4.95 5.12 4.69 6.01 4.61 6.34 4.79 6.54 9/28/94 357 4.76 6.35 5.20 5.08 6.49 6.95 6.51 6.45 6.47 4.70 5.05 5.45 4.71 6.00 4.60 6.32 4.77 6.33 10/19/94 378 4.85 6.25 5.12 5.15 6.45 6.79 6.40 6.71 6.48 4.84 528 5.89 4.77 5.98 4.59 6.62 4.75 6.35 11/16/94 406 4.79 6.27 5.22 5.53 6.54 6.70 6.30 6.57 6.50 5.02 5.58 5.99 4.77 5.95 4.60 6.11 4.72 5.96 12/23/94 443 4.65 6.15 5.19 6.07 6.55 6.92 6.25 6.36 6.37 5.23 5.53 5.77 4.78 5.84 4.62 6.12 4.76 5.89 1/11/95 462 4.81 6.18 5.39 6.14 6.49 7.14 6.30 6.30 6.37 5.37 5.82 5.92 4.82 5.92 4.68 6.10 4.80 6.00 1/18/95 469 4.93 6.01 5.66 6.06 6.21 6.42 6.40 6.40 6.26 5.90 5.71 4.98 5.97 6.00 4.78 5.98 1/25/95 476 4.95 6.02 5.64 5.95 5.94 6.14 5.16 6.23 5.83 5.83 5.03 5.90 5.94 4.92 5.94 2/1/95 483 5.07 5.72 5.69 5.90 5.90 6.17 6.12 6.17 5.91 5.79 4.91 5.81 5.89 5.01 5.83 2/15/95 497 5.30 5.92 5.73 5.94 5.95 6.26 5.97 6.10 5.76 5.66 5.19 6.00 5.88 5.04 5.82 3/1/95 511 5.20 5.94 5.88 5.89 5.89 5.97 6.19 6.16 6.02 5.63 5.32 5.95 5.91 5.03 5.83 3/15/95 525 5.23 5.85 5.81 5.75 6.07 6.05 6.16 5.95 6.11 5.90 5.77 5.55 5.24 5.69 4.62 5.95 5.23 5.74 3/29/95 539 5.58 5.84 5.80 5.72 6.13 6.00 5.97 5.88 5.89 5.49 5.58 5.79 5.91 5.24 5.78 266 Appendix F. Leachate Characteristics Data t 267 F.2 Volatile Fatty Acids co 27870| 33480 10860 7160| 6350 5655 50201 5243 4495 3612J 2778 2046 1438 1269 0 10 CO CM cn Tf O co CM CM 0 10 cn CM h- CM 5 CM Tf CM CO co r» 29420 29260 15970 9040 6450 6010 5060 4118 3935 3462 3084 2830 2963 3695 3995 4413 4644 5526 5652 2240 6181 5334 5101 4481 3770 3374 1587 0 co f CO r-co 0 CM co CJ) Tf co h-LO CM 0 Tf co 28770 29410 11230 7380 6650 4440 3555 3260 1954 1479 1433 co co o> •* CO CM LO CM LO CM LO h. co LO LO Tf O) CO CM r- h- Tf Tf CO 0 LO CO LO LO 27370 30160 12340 0068 9650 4695 3775 3923 3408 3053 2617 2319 2525 3447 4023 4929 4977 6706 7497 7431 7531 7029 5899 5690 4467 4236 3606 0 34130 53260 14390 9930 10950 6890 6495 5690 5115 4471 4229 2836 1742 1742 1194 co 0 CO LO h-O Tf 0 0 CM CM LO cn CO LO cn cn h- co co LO co co Tf co 0 co 30250 31450 13250 10090 9100 7195 7250 6855 5948 5226 4995 4144 3417 3378 3000 2192 2062 1634 CM lO 1438 1194 CM CO co CO co s co CO hi CM co 0 Tf r-0 co co CO CM CM co Tf cu Tf 0 CM h-0 CM 35670 51940 12550 7860 10700 5940 5290 5350 4568 3911 3861 2867 1800 1329 1314 10 co cn 0 co cn co CO h. 00 f-O) co f-0 Tf co co CM co Si *-0 co LO O) co cu co LO cn 32340 35250 15790 10810 10100 7440 6855 6233 5830 5520 5231 3946 2498 2004 CO co c-CM co CM 90S I. 0 0 0 Tf co h-h-LO h-Tf Si 5) co CO 0 co s CM CM co 1— § O) Tf h-co Tf Tf CO h. O 30540 35220 12320 7480 7800 7105 7585 8588 7765 6386 6218 5379 4160 3947 3375 2560 2390 1908 1638 1807 1063 00 0 00 CO CO CM Tf co LO O Tf oo co cu O CO 31710 30880 11170 7780 6500 5625 4840 4480 3748 3489 3193 2842 3254 4357 5176 4198 3826 2854 2506 1882 1148 Tf f-co LO O) co cn TJ-co CJ) r- LO 0 CM CJ) Tf 0 O co 40230 33170 10890 7150 7650 5670 5365 5318 5693 4731 4508 4325 4940 5479 5422 5148 5429 4730 4303 3186 2497 co CO cn 00 in Tf h- S! co co CM h. CM LO co Tf O 35820 27980 11900 7310 5950 5695 5870 5540 4790 4210 3677 2784 2395 1779 1353 Tf 00 CO f» Tf CO co cn 0 CM 0 Tf f- Tf 00 co CM co O CO 28310 29680 13560 7660 7750 4785 3230 3600 3290 2555 2037 1802 2670 3456 3564 3481 2888 2702 1997 1823 1492 co 01 CO CM s i co 00 h-CO 0 cn cn CM CO co Tf co CO LO 36390 30270 13640 9100 8450 6125 5520 5410 3373 2858 2614 2917 3602 4015 3638 3032 2766 2748 3081 3015 2332 1378 co cn cn CM LO h. cn co CO h-CU LO LO 8 00 Tf CM CO O) h-co CM co 00 0 CO LO Tf 30880 28110 11910 8020 6150 5120 4885 4381 3668 3244 2870 3053 2798 3639 3336 2665 2316 2047 1860 1862 1475 1009 CM hi £ co co o> 10 h. Tf O co co Tf 10 Tf CO 44570 29080 11370 7400 6350 4955 5105 5343 3773 3200 3053 2842 3009 3241 3018 2993 2837 2542 2658 2373 LO Tf o> Tf CO CM 0 Tf h-3 0 CM O h-O) h. cn f-co CM CO co cn co O) LO 0 co co CM 34300 22290 13040 8940 8300 6320 5685 7483 4478 4508 4051 3315 2553 2279 1768 1299 1061 c» Tf co co CO CM CO CO 00 o> h- Tf 0 h- 10 CM o> co 23630 28990 15940 10190 6800 5910 5675 5048 4193 3788 3648 3294 3263 3693 3532 3120 2992 2695 2713 2300 1777 1152 3 cn 1028 f-10 cn 11 co LO co co cu co CM h-co CM Tf co co co LO 00 CM o co LO 0 h- co co o> CM i— co CM 0 a co co CM co co O) 0 CM co CM LO Tf CM co co CM Tf O) CM oo 0 CO cn CO f-LO CO i CO co 0 Tf CO CM co Tf O) co h-Tf co 00 Tf h-O) Tf LO LO 0! LO O) s /FA(mg Time (c _g % co £» 120/10/93 117/11/93 CO a> 15/12/93 co •«r SJ Tf cn Tf Tf cn Tf S> Tf 9> Tf 9? Tf cn Tf Ol Tf cn 3 t cn Tf Tf £» Tf cn Tf O) LO LO 82 10 cn LO 9? LO 9> 10 cn LO O) LO SP Leacha Columr Date 6/10/ 120/10/93 117/11/93 c\) 15/12/93 O) CM CM 26/1/9^ I 2/9, 2/23/ s CO I 3/23, CO 4/20, 10 5/25, CO CD 6/29/ I 7/27/ 0I78 | 8/31/ 9/28/ 10/19/ 11/16/ 12/23/ 1/11/ — I 1/25/ 2/15/ co 3/15/ 3/29/ Appendix F. Leachate Characteristics Data 268 F.3 Distribution of VFA types GO 13910 5150 o CO 7880 o O) LO 27870 14270 5150 LO 8930 4560 33480 5640 1430 O co 2820 o 0> r-10860 3390 1120 o LO 2030 o 7160 3450 o m 00 o o 1650 o o co 6350 3120 in co r~ O 1285 LO o -<* | 5655| 12920 3750 o o 11840 O Lo 29420 13030 3730 o co co 9820 2020 29260' 8880 1630 o co co 4530 o o co 15970 4550 1010 o •* CM 2660 o CO m 9040 3700 o o co o in 1750 o 10 CM 6450 3455 in oo o> O CM 1220 o co CM | 6010 CD 14190 5040 o co 8260 O) 28770 13440 4980 o LO t 0999 3880 29410 6200 1800 o LO 2450 o CO co 11230 3590 1290 o T— 1760 o CO co 7380 4200 o o 0) o o 1150 O O CO | 6650 2640 in o> m m o co co o r-CM | 4440 LO 12440 27801 o in •* 11120 o oo LO 27370 10580 2690 o 8 10620 5590 30160 5580 1090 o Si 4750 o 00 co 12340 3050 o O) o | 3180 | 1530 8900 4100 o o i*~ o in 2500 1 2200 | 9650 I 2130 m in o | 1750 in CO CM | 4695 Tt 17620| 53001 IS) 9630 1010| 34130| 22440 6040 1610 15080 8090 53260 7250 1430 o CO •* 4580 o o f~ 14390 | 4740 | 1160 o Si co | 3020 o 0) co 9930 | 4500 o o o> o o CM ] 2350 1 3000 | 10950 | 3895 in CO LO r» | 1820 in oo co ] 6890 co 15600| 28701 o o co 10600 o oo in 30250| 15340 3250 1100 9740 2020 31450 7820 1100 o co co 3500 o r--| 13250 | 5450 o in O) o r-co | 2780 o LO 10090 | 4850 8 CO o in CM I 2000 1 1350 | 9100 | 4465 SOS I o CM | 1685 o CM | 7195 CM 16710) 29301 o 5) 14580I o LO 35670| 24830 4980 1910 20030 o O) | 51940 | 6830 ] 1100 o co co | 3780 o co | 12550 | 4160 o co r-o co CM | 2360 o m CO I 7860 | 6700 OOS I o o CM | 1700 | 1600 | 10700 I 3740 m o m LO | 1330 O a | 5940 ^ 13970| 31601 o 0) 13490| o LO P-32340| 13050| 36401 1300] | 11010 | 6250 | 35250 | 8280 | 1560 o | 4470 I 1010 | 15790 | 5400 | 1170 o o> CO | 3010 o 00 | 10810 | 5200 o o co o o co | 2350 I 1450 I 10100 | 4335 o r-m in CO CM [ 1875 in 5! | 7440 o 15360| 18301 o o> r-12560| o 30540| 15820| | 2170] | 1190] | 11310] | 4730 | 35220 I 6870 o o CD | 3830 o 5! | 12320 | 3960 o in m o in CO | 2380 o Si ]7480 | 4850 o m o LO CM | 2050 o o CM ] 7800 | 4565 in LO co CM P1750 o CM | 7105 0) 16420j 22501 1070| 11970| o 31710| 15610| 2810 1470 10990 o | 30880 | 6240 | 1080 o | 3040 o | 11170 j 3940 0 co 01 o co | 2140 o o | 7780 [ 3850 o in co o m CM f 1500 O in CM | 6500 | 3490 o CM m o o CM 1185 O co CM | 5625 co 16570| 30901 19080| LO 40230| 14580| 3310J 1140] 11460 2680 | 33170 [ 5690 o 5> o CO \ 3420 o CD LO p0890 | 3550 CM | 2270 CO | 7150 | 3750 o in co o | 1900 1150 I 7650 | 3205 m LO o co I 1510 O oo CM | 5670 r*. 14260| 40201 15750| 10701 35820| 10100| ] 3200| o LO 00 10830 | 3000 | 27980] | 5280 | 1220 o co | 4280 o co h-| 11900 | 3100 o LO CJ) O CO CM I 2550 o CO | 7310 I 3150 o o r-. o LO I 1700 o m CM I 5950 I 3275 o m in CO I 1350 in cn co | 4785| 5695 CO 13670| 31601 o co 10890| o oo CM 28310| 14170] 4110 co | 10780 o | 29680 0989 | | 1560 o CM | 4050 o oo | 13560 | 3680 1 1080 | I 2330 o co | 7660 3400 o o r» o o I 1650 I 1900 I 7750 I 2845 o -a- m oo | 1120 m O) CM | 4785| 5695 LO 157401 55701 o co 13500| O •f O) 36390J 11190| 5230] o CM oo | 10100] | 2930 | 30270 | 6630 | 1850 8 CM I 3980 o co 0) I 13640 I 4150 I 1310 o o CM I 2690 o LO I 9100 I 4000 I 1050 o m I 2150 I 1100 I 8450 I 3105 o cn CD o co I 1670 o CO in | 6125 •<* 147101 31901 o G> 118101 o o co 30880I 13240] ] 3260 o r-0) I 9880 o co I 28110 I 6420 I 1060 O 00 CM I 3490 o co CO I 11910 I 4150 o Si 00 O SI I 2380 o in <* I 8020 I 3650 OOS | o m I 1650 o o CM I 6150 I 3075 o co o co I 1280 m O) CM 5120 1 Leachate Volatile Fatty Acids Distribution (mg/L) co 193801 57001 o LO co 171401 15001 44570I 11410] ] 4140] | 1050' I 10370 | 2110 | 29080 I 5370 | 1390 O Si co I 3420 o r-oo I 11370 I 3350 I 1110 o co CM I 2140 o r-LO 7400 I 3350 o m co o m I 1650 O in co I 6350 2735 o o in o co 1200 o 0) co 4955 1 Leachate Volatile Fatty Acids Distribution (mg/L) CM 130401 47301 o CM co 152301 o oo CO 34300I 8590 3510 069 | 0096 o 22290 I 6340 I 1720 o Si I 4000 o | 13040 I 4250 I 1250 O o CM I 2630 o CO 8940 I 3750 I 1050 o in I 2150 I 1200 8300 3450 o in h-o co 1645 in co 5910 6320 1 Leachate Volatile Fatty Acids Distribution (mg/L) T— 8050! 22501 o CO 97201 32701 23630I 11940 | 3610] o 8 I 9690] I 3150 | 28990 I 7350 I 1540 o CM I 4070 I 2770 I 15940 5830 1120 O 0) 2380 o CO 10190 I 3950 o in 00 o m I 1800 OS | 6800 3200 m oo h-IS) CM i— 1400 o o 5910 6320 1 Leachate Volatile Fatty Acids Distribution (mg/L) VFA Type Acetic Propionic Iso-butyric Butyric 1 Others Total Acetic | Propionic | Iso-butyric | Butyric I Others Total Acetic Propionic Iso-butyric Butyric Others Total Acetic Propionic Iso-butyric Butyric Others Total Acetic Propionic Iso-butyric Butyric Others Total Acetic Propionic Iso-butyric Butyric Others Total 1 Leachate Volatile Fatty Acids Distribution (mg/L) Column # Date 10/6/93 10/20/93 11/17/93 12/1/93 12/15/93 12//29/93 Appendix F. Leachate Characteristics Data 269 00 2840 LO Tf to 1125 in CO in f-CM 5020 2933 8 to O cn 1048 m LO 5243 2580 OSS o in CO cn 8 Tf 4495 1888 m o m O 3 00 h-Tf 3612 1234 Tf cn Tf 0) to cn Tf 10 CM co Tf 2778 Tf a> co Tf CO in Tf co co 3 CO 1 2046| h- o CO O) CM o o Tf o CM in in 3 o co o in o 3 CM lO o co co cn co cn cn co CM oo Tf o in Tf CM 8 CM o co CO cn O CO m CO o CO o r--o CM co oo O 10 f-00 cn Si CO CM CO Tf CO CM f--co CM CM 3 o CO f» oo r-co Tf oo o CO co in m CM Tf co LO 81 h-Tf m co 8 oo CM 10 in CM in 01 in O in Tf h-o in in in co O O f-10 S 8 co r» L0 10 h-co o co CM co cn f-0) CO LO Tf o o o Tf co CM 3 a> 1 O CO 0) CM 0) 0) N-Tf o h-Tf CM co Tf CM Tf co 81 co CM co co Tf CO cn CM f-CM 00 CM co Tf co co co in 00 Tf in LO co in f~ m t»-co in 3 in 5 co 8 co 00 CO LO CM co r-Tf co S> CO m CO co CO CM o in o> cn in CO co co o Tf CO to h-lO o CO CM o LO CO co 8 CO CO LO O CO s CO to CM CO h- O) to Tf 3 f-co CM o o co Tf 3 h-r-in o> CM Tf O) CO CM m i— LO co o to to o to in CM to in co m m o> 3 in CM CO in co to co co o in co I o cn co LO s CO LO co 10 o co o CM co o> 10 in O co h-CM 81 LO r--in o CM co o £ Tf Tf Tf co CM CM m m co CO CO a> O) cn CO cn 81 Tf to oo Tf O) o co oo in LO co co co Tf co co 3 CM co m in in Tf in to in o h-CM m to in Tf CM o in 8 co h-m in CM oo LO co oo CM in in CO co co co m o m o cn oo Si CO s T— 3 cn in i in o LO oo in Si co CM o to m CO CO CM o> m in to Tf co cn o co co co m cn O) Tf co cn co CM Tf cn CO CM 00 Si 0) h-co Tf Tf Tf CM o r-co LO 0) co O CO s LO Tf Tf 8 CM in 3 CM CO s Tf O Tf in CM CO cn co o in co m co o co in m co o o h-cn If) 81 00 to to Tf CM to in CM co a> CM o 5> 0) co cn co to CM o CO co oo o oo CO 00 co CO co CO m oo in to Si cn CM co 00 CM ^ in CO cn co o CO LO in cn o CO to in to in LO s co CM co in Tf co oo in to CO I co co CM to o 8 CO h-co o f-co 0) CM tn co o co oo in co o Tf co co o CO CM co o co CM r-Tf o CM in in to CM CO co r*. CM to Tf co 00 o in co CM tn co co CO CM 0) co r>- to cn CO co 3 co 3 CO o in co o in o LO CO in CM o Tf r-in o CM m 00 m h-in CO 0) LO in CM CO LO o CM to cn oo oo cn co 00 LO co 00 in m in o m CM co m 00 o m to 1 cn m o to co CO co oo to Tf to CM Si cn o CO Tf o CM 00 CM co LO to CO CM Tf co in LO CM co f-cn ft m CD LO co GO CM LO m in o r- in in O) in cn CM o 3 Tf co co to CM CO o> m o in m to h~ o CO o oo 5 co 3 CM CO to o co 3 o oo Tf f-co h-co CO m to o co to m o CM Tf cn 3 co m 3 h-3 CO o to f-Tf o> o in co o> CO oo o Tf in CM Tf f-co h-CM Tf co O) Tf CM 3 CM oo in CM CO CM m CO m in co m in to LO in 8 in 10 8 CM co s o co o cn m s oo co in | co o 8 o co o 10 CM co 8 co o> co in o CO CM co a> m o 8 *— h-3 Tf 8 CM co Tf co co co in m co oo o to Tf CM CM 8 cn o Tf o> h-0) in Si co Tf r- LO CM CO o O) 10 in o o CM o s o 1". CO in co co1 o co to CO m cn o f-co o 3 LO co CM CO CO f-m o co cn r-co o co o 0) r-Tf O to CO CM oo 8 o co in to LO 8 o § O CM CM LO o> r- co Tf LO Tf CM Tf r--co CO Tf o co cn 3 to CO Tf CM Tf 3 Tf oo r-CM CM o co co lO o a> LO o O O 0) o o co CM CO 8 8 in CM 1 s ? 8 cn oo to co o o oo m tn co Tf 8 CM CO O CO Tf co Tf co o co co Tf o LO co in m m CM CM 00 o> CM h-CO cn co o CO CM Tf CO CO h. 8 CM co cn co co CM co co o Si m co in o s CM in h. CO 10 in Tf m co CO o CM m in s co CM m 8 CO cn 8 v— co in CM o Tf LO o a> m o o CO o 00 o 3 CO 8 CO oo CM in 0) CO o o m CO in CO m 00 CM CO m o CM O Tf co oo LO o CO m Tf CO CM co h-Tf Tf 0> Tf h-h-LO to o> LO 5 CM Tf LO o co CM in o co in in LO 3 LO o CM 8 CM CO o CO ft cn 8 i m m Tf CM oo to o CO to co 8 8 8 CO CO 0) 8 o o Si co § co CO cn in CO CM r-00 LO h-in co CO O f-00 CM Tf 3 co Tf co co o oo co in co co in o co 1 Leachate Volatile Fatty Acids Distribution (mg/L) co in CM co CM o s o CM in S LO CO h-m o in m h. co CM I co L0 8 CM m JO in to CM co 3 o co co co in Tf co 1^ co co 3 co h-CM o o o to co o o Si co cn m co Tf CM Tf 00 Tf h-CO co s CO in 8 o o> o co co cn LO h-CM to CM 3 CM 1 Leachate Volatile Fatty Acids Distribution (mg/L) CM LO co h-CM 3 in CM in Tf Tf o 3 in 8 in co to Tf CO in to oo co Tf LO 3 8 Tf 8 Tf h-LO 3 CM o f» m o o Tf o 3 co co h-Tf Tf co 5! CM in in in o oo Tf o oo h-Tf co o LO Tf 8 oo to LO CO CM 3 oo 3 co LO O Tf 81 Tf CM Tf co o co 0> CO co o to in CO CO 1 Leachate Volatile Fatty Acids Distribution (mg/L) o o CM LO 00 co m i— *— in co 1 in to in w in CM 10 8 co Tf LO CM co o m o co cn r-o 3 CO 0) Tf 8 CM S o o Tf h-to Si co co co h. co CO co o CM cn 3> 8 co m to CO Tf 3 co co 3 co m CO co P2 ft LO Tf 3 CM co 1 Leachate Volatile Fatty Acids Distribution (mg/L) CD CL < LL > o < u 'c o 2 a. 3 XI 6 o & 3 m CO CD £ O 1 .2 0 1 o c o CL O CL o .& 3 XI A — o 2-3 m CO <5 £ O 1 O f-0 1 o 'c o CL g CL o XI 6 o 3 m CO CD £ O a .2 0 '•£3 1 o 'c o CL o 0L o .& 3 XI 6 O £• 3 m to CO £ O a 0 1 o 'c o CL 2 o_ o 3 XI 6 tn o & 3 m CO 1 o a .2 o < o 'c o CL o o 3 XI 6 tn o 3 CD to CD £ O a o 1-1 Leachate Volatile Fatty Acids Distribution (mg/L) c E o o 1 Q Tf 1 Tf a> CO Tf Tf co 8 Tf cn gj CO Tf CJ CO Si co Appendix F. Leachate Characteristics Data 270 03 co o tv co CO CO c% O) co CM cn CM 1438 rv CM m co CO o> CM tv |v m CM 1269 CM co m CM CM 5 o co 0) CM o 0> CM CO m 00 CM in CM CM o o o cn in CM CO cn co o o rv O tv cn in cn to 5> tv cn co CO CO cn CM oo o CM 10 co 00 CO co co 0) tv in O) CO CO in oo 81 m tv o co CM m cn cn co in co co CM CM o oo CM in 0) co co |v o |v CM |v oo in oo |v CM CM cn co co in CM co cn 81 CO o 00 o m IO CO CD CM m m co co CM CO CM cn to oo in co o co oo o CM co o CM O CM in CM in o CM o O o co o CO CM CO IO IO o oo o m CM m |v o o O o m |v co o o o o CD in co o CM o CM CM co tv cn to m tn -t in CM 10 CM 1 CM co r- co 8! f~ co CM co 00 cn m in 10 CO co CM s co s o s in cn ft! •<t tv CM CO m GO co o o in fv 0) •«t oo CO o CM CO o co IO cn tv 10 CD o |v co lO co oo tv co CM co co PI CO •* co CM in CO oo rv co CM co co CM CM iv in oo o CM cn CM CM co CM O) co CM CM |v co co co PI |v oo co m o o co IV o co in in co co o O) co CM in IV o CO •c— CO O) 5 oo CO 15 O CM iv s co O) O 8 15 co in iv co tv CM 00 co co o s CM in CD i in O O 8 in CO CM m o CM Si O) CM 0) m oo o 00 CM m o CO CM CM CD o CM co o cn o 00 CM in CO I CM oo cn o CO co •<* co iv o CM o o oo co oo cn oo o •* co CO CM cn CM co co Si co CM m cn CM h. co co CD co in co |v oo O) 8i co |v in co cn co in oo co o a CM co co o CO cn co m o |v cn o oo CO oo pi ^- tv co oo oo CO CD in m C\J CM 00 cn CM o 00 CO co in in 1 o in m o> in in CO cn co co CO CM 00 co h» O) CO Si co 00 co CM •* |v Si co CM 5) tv |v in cn co CO co in IV m o m CO oo in Si co o cn CM CM cn o tv 0) |v CM o co 8 CM 5 CM O o co 8 tv CM o oo 10 o cn in cn -a-rv cn CO co 81 CO co CO oo 55 oo co IO in CO CO t-. cn co co tv co IV CM CO co o O co m CM 81 co o CM m co CD pl o CO CM in o in o cn co 00 o O) 0) 8! CO U) CO cn in cn co o m tv CM in lO CM CO CM CO CM •* |v 00 cn iv co in CM co |v in co m CM 3 m CO co f| in o PI o cn 00 cn co PI co |v 00 tv 00 cn CM co CM |v 0) o •>* co cn o co CD Si co CO CO PI CO co oo in in co in o IV in oo CM co CO CM co co o CM O) oo CM 3 o cn O CM m CM co 8! co co co oo cn cn 5 cn tv in r--m CM in ft! 0) CO co in cn 0> o m co CM co 5 CM cn in tv co IV o oo in IO 81 in co co Iv |v co CM cn CM in co cn cn s cn tv m co co cn oo o CO rv •<t tv co CM in CO CO CO tv in co CO in cn co CM o 3 & co co co s CM CO co 0) tv tv co CM in in co oo in cn fi! CM co in co o CM co 81 •* co in in s co Pi in o CM o o PI IV co o oo o> o o o co cn co CO co in co co •<* CO CM co 0) co o CO CM 0) O) CO co •* q> m in co CO o in co in •<* co co cn 00 CO co in in cn m •* in s IO CO CO oo co in co co CO cn CM o co co co O) CM m cn CO CO oo CO Si CO CM CO in 00 co oo CM 00 co o PI CM co in o co s IO 8 rv CM in in co co CO CO CM co oo CO |v o 00 s CO co tv •* o o 00 o o> in o cn CO |v o CO o CO o CO r~ co 0) 00 co co co Si co o in co CO CO cn CO oo CO CM in 00 % o co Iv 0) Iv oo CO CO cn •<*• CM CO CO pi CO co |v CM o CM o o 00 oo CO co 10 CD rv 10 00 fv CM •<* 00 co m co CM i— o co in h-iv o o CO 00 cn CM o CM CO lO T— T-f- 5-0) in co CO cn co co co CO co cn 0) in CO co CO co oo m co CO co co co CM co 00 CO in co m 81 m co CO CM o o co oo |v co co CM oo Si co CO cn o CM m in oo |v o CM 1 Leachate Volatile Fatty Acids Distribution (mg/L) I co o rv <£> f-i— to rv CM iv in co in O) O O CO cn CM CO o co co iv cn in h-o o CO CM co in oo co oo co o oo IO oo 8 co o in in co co co o> CO co |v m co cn in o co co pi o 0) Iv co 00 CM in co CM CM CM m co IO CO |v 5! 5! ID CM 1 Leachate Volatile Fatty Acids Distribution (mg/L) I CM CM CO T~ co oo oo co 00 IS co in in CM 00 O) o cn |v |v in co o> tv 81 s co § CM CO o co CM oo 8 oo co r-IO co cn co in | CO m CM cn o CM CO co 00 m co o CM oo CD CM CO o o |v CO o CO CM m |v 1 Leachate Volatile Fatty Acids Distribution (mg/L) I cn tv to o co o co |v tv CO CO o iv o CM 00 r— •Q co co co co in co CO cn co co o o O) CM co cn 00 m IO S CM co in CO CM IO CO o cn co o co cn in o CM CO o m m co 0) in oo co oo Iv ft! 0) CM cn cn co CM co co CM IO o in cn CO CM 1 Leachate Volatile Fatty Acids Distribution (mg/L) I CD Q. < LL > 0 1 o 'c o Q_ 2 o XI 6 tn o §• 3 m CO CD SZ 5 1 u 1 o c o CL o CL o & 3 XI 6 tn o '!> 3 CO CO CD x: O I o < O 'E o Q. 2 0. o % 3 XI 6 — o 3 m CO CO x: 5 1 o < o 'c o Q. S 0. o S> 3 XI 6 tn o 3 m CO CD £ O 1 0 1 u "c o CL 2 0-o & 3 XI 6 _co 3 m CO CD x: O 1 o 8 < o 'c 0 01 s 0. o 3 X) 6 tn g 3 m CO CD x: o 1 1 Leachate Volatile Fatty Acids Distribution (mg/L) I % c E 3 o o fi ca Q S cn o CM •*r 9? in •>» S! IO S! IO cn co CO Ti en cn co Appendix F. Leachate Characteristics Data 271 oo rf O) o o o co CM CM o o o o CM o o o o o o in o o o o in cn o o o o cn CM o o o o CM h-35351 co CM o 1409| CM CO Tf 5652] O CO 1— Tf | 1497 cn cn Tf | 2240 | 3735 io CM co CM 1 1570 o 10 1 6181 j 3259 co B! oo | 1472 o Tf co | 5334 | 3119 co h- 3 | 1402 co B! co | 5101 | 2695 cn co 0) h-| 1148 O) co co | 4481 CO LO o o o o LO LO o o o o LO Tf O O o o Tf cn o o o o cn oo O o o o co o o o CM LO 45821 h-3 h-o> 15291 3 j 7497j | 4428] CO 3 CM o I 1568 s CO 1 7431 I 4550 CO Tf o | 1560 co h-co | 7531 | 4118 co CM 00 | 1636 CO 00 m | 7029 | 3462 CO CO Tf Tf h-] 1396 3 | 5899 | 3375 LO 8 Tf h-| 1163 CO h-10 | 5690 Tf h-CO co h. LO CO ft o o CM CM oo o Tf oo CM LO LO CM LO o o o cn CO in o o o o in 0) o O o o cn CO i— O o o cn co s co o 3 0) CM LO co oo h- cn Tf o C^ co co oo | 1438 CO LO CO o CM h-Tf | 1194 cn oo Tf o oo h- Tf cn Bi co co oo 0) co CO1 O in Tf 8 h. oo co CD h-co LO LO O CD in co 0) 3 CD CM h-5 £3 o LO CO o CO h. oo LO CO Tf LO co o o CO r-co h-0) CO co Tf CM CM CO o CO CO o h. o Tf h-oo h-m o 0) CO o co CO co o 8 O Tf o CM CD CO h-Tf O o o Si ^ o o o o o o CO 10 CO 3 CM 3 CO co CO 0) CO | 1764 3 Tf Tf o o Tf cn Tf h-in r-LO Tf oo h- oo Tf CM CM in Tf CM h- oo CM 3 O 3 Tf 5 CO in co o Tf CO 8 co o 0> CO o O) o Tf o oo 1638] | 1218: CO Tf o CO LO Tf h. oo I 1807 o CO CD CD CO o h-co co o \ 1063 CO SJ CM o co SJ ft! co oo o oo Tf Tf in O CO CO CD o CO i— o CO V-CM CM CO Tf CD CM CO LO co 5> 0) oo CO co | 2506j i LO h- co 0) CO 10 | 1882 LO co oo CM 10 3 8, CO | 1148 8 CD 81 o O o 00 Tf ft 00 h- CO o o o m CO 3 o CO o o o CO CO 00 1935| 10011 CM h- s 10 10 co h-| 4303 co co cn CO 8 0) CD o 8 00 | 3186 | 1109 cn 3 co Tf CO CO CO Tf CO Tf | 2497 o h. CO cn ft Tf CM co CO Tf m CD CO 0) oo CM co CM o oo LO o h- oo LO cn Tf o o Tf Tf h-h. o o o o o o CM o o o o CM o o o o o o Tf o O o o Tf h. o o o o h- Tf o o o Tf (O LO h-CO CO CO CO CO 1— LO Tf | 1997 CM LO CO s LO CO Tf CM 00 0) h-co | 1823 Tf 3 LO CM in 00 co h-Tf h-cn CM I 1492 CO Tf CM oo CM O CO CO cn CD CO in CM co h- o h-co CM CO CM CO in co in CM o in CM Tf Tf Tf LO 14941 h-CM Tf O oo LO 3 10 co LO | 3081 | 1509 oo 00 h- co s h-| 3015 | 1189 co CO co h. LO CM Tf 3 I 2332 CO 8> CM oo CO co o CM [ 1378 CO CM LO co cn CM CO o CM in co cn cn co 3 oo CO CM in co co CM Si h. Tf 1183| co oo co co 3 Tf h-CM j 1860| | 1215! CM 0) LO CO CO Tf 10 o | 1862 o LO 0) in r- 10 CM co co o I 1475 00 hi O m o 3 co in I 1009 CO m in CO Tf o CO CO CM hi co in to 0) o o oo Tf co CM h-| Leachate Volatile Fatty Acids Distribution (mg/L) | co 14981 o> 3 cn 3 CO CO CO 2658 | 1345 CM h- CO Tf ft co CD 8 | 2373 | 1150 00 to Tf CO co CO Tf CM I 1945 10 00 h- o> CO o CM 3 00 CO I 1264 cn in h- 8 o CO in CM co 00 I 1140 o h-oo h-CJ> o co CO CM co | 1347 | Leachate Volatile Fatty Acids Distribution (mg/L) | CM h- B! co h. cn O CO co co CO o o o o co CM o o o o CM O) CM o o co co o o o o co 00 o o o o co | Leachate Volatile Fatty Acids Distribution (mg/L) | 1415| h-CM co co LO i T? 2713] I 1228! co CM LO Tf h-CO co 8 I 2300 O co CO Tf CM Tf CD CM m o co I 1777 h-10 CO 0) CM 3 m Tf co h-I 1152 CO co o o in CM 00 CM CM 3 0) CO co CO 0) o co CO in h-CM | 1028 | Leachate Volatile Fatty Acids Distribution (mg/L) | VFA Type 1 Acetic | Propionic J Iso-butyric I Butyric 1 Others Total j Acetic | Propionic ] Iso-butyric Butyric Others I Total I Acetic 1 Propionic 1 Iso-butyric 1 Butyric 1 Others I Total 1 Acetic 1 Propionic 1 Iso-butyric Butyric Others I Total (Acetic [ Propionic Iso-butyric Butyric Others Total Acetic Propionic Iso-butyric Butyric Others Total | Leachate Volatile Fatty Acids Distribution (mg/L) | 1 Column # 1 iDate 1 I 7/27/941 I 8/10/94] I 8/31/94 9/28/94 110/19/94 11/16/94 Appendix F. Leachate Characteristics Data 272 03 o o o o tv CM o O o o CM CM o o CO Tf Tf CO o o o o CO CM o O o o CM Tf o o o o Tf r-23071 CO CM o o to 0) in CM 37701 20211 o IO CM in co to oo CM CO CM | 3374j CO m co co o co cn Tt Tf o tv 1587 co tv CM in o Tf Tf oo Tt o co Tf CM Tf CM |v CM o co co CM co tv CO O o CM tv CM Tf 8 CO CM o CM CO 10 tv O o o o fv fv o o o O |v o co o O Tf Tf o o O o Tt CO O o o o co O O o o o o m 27401 co o CM 00 0) 44671 [ 2464] 8 co TT in CM Ti en 00 00 CO | 4236 | 1975 cn fv CM in m co cn 00 Tf o Tf 3606 O o o O o o O O o o o o O O o o o o TT fv o o O o tv to o o o o to to O o o o co in o o o o IO CO O o o o co co O o o o co co in CM to o Tt CO 00 co fv to co o tv o Tf T— tv to CM to o co CM Tf Tf to oo |v CM m o Tf CO IV CM CO o o CO 0) co tv o CO CM CO Si co o cn CM 8 CM in CM S! co Tf co co CM si CM ^~ O o o o i— o o o o *" CM to o O o 8 CM CO o o o in 0) o o o o cn CO CM o o o O co CM -fv <£> 8 CO to CM to s CM Tt CM o o o CM to r-CD tv oo o tv to O) o o Tf cn o o o cn Tf 0> CM oo o o o fv co CO o o O Tf o |90S O) o CO O) IV Tf 1 CO CM o m |v o to co Tf |v CM |v co 00 to 03 in o Tf o o o o o o O o o o o o O o o o O o 0) 8 o o o fv o o o cn tv O o O o fv co CM o o o in 8 o o o o 8 O) o o o O cn 03 co co CD Tt o o o 3 co O o o o co CM o o o o CM CO Tf o o o tv CM o o o o CM m o o o O m r- 00 O o o o co CO O o o o CO CM o o o o CM o O o o o o O o o o o O o o o o O o co CM <o Tt CM o O o to oo 8, IO Tf o o o tv co O o o o o o tv 03 CM o o o cn cn m tv tv o o o Si CO co o o o o co in CO (O CO tv CM S! co 5) cn 03 to to CM CO loot. | o o m m |v CM in cn Tf CM 8 co o m in co in 03 CO CM CO O CM tv m co co CM oo Tt CM |v CM CM in co CM oo co cn CO oo co co cn o tv co Tt CM CO to 0) o in o oo to 0) cn Tt to CM o o o IO tv 1— to in O o CO Tf tv fv co O o o o Tf in CM in o o o o co in o o o co Leachate Volatile Fatty Acids Distribution (mg/L) J CO CM <o Ti to SI CO CM m cn [ 1020] IO in CO Tf o co in in |v |V cn tv tv CM cn co cn co tv Tf 0) IV CO tv tv co in Tf to CM CM tv cn Tf CM o IV CM in CO co CO oo CO CM CO rv o cn co Leachate Volatile Fatty Acids Distribution (mg/L) J CM cn O o O o 0) tv o o o o tv cn m o o o Tf tv co o o o O tv O o o o tv in o o o o m Leachate Volatile Fatty Acids Distribution (mg/L) J 03 to § o in Tt 8 tv in cn cn oo Tt CM m CM 8 SI CO O) S! oo fv co 0! to co in in tv Tf m co co co Tf Tt 0) 8 CM CM CO CM s CO Tt 0) CO CO CM tv CO CM in cn CO Tf CO 8 |v s Leachate Volatile Fatty Acids Distribution (mg/L) J VFA Type | Acetic 1 Propionic I Iso-butyric I Butyric I Others I Total I Acetic Propionic Iso-butyric Butyric Others Total Acetic Propionic Iso-butyric I Butyric | Others I Total | Acetic Propionic Iso-butyric Butyric Others Total I Acetic Propionic Iso-butyric Butyric Others Total Acetic Propionic Iso-butyric Butyric Others Total Leachate Volatile Fatty Acids Distribution (mg/L) J Column # 1 Date 12/23/94 1/11/95 1/18/95 1/25/95 2/1/95 2/15/95 Appendix F. Leachate Characteristics Data 273 oo o o o CM Tf o o CM o CO o o CM o CO I-- CM CO CM m co r- o co m 0) 3 O) co CD CM Tf o m 00 r«-m CM CO oo Tf co in CM m o Tf (0 in o o o o 10 o Tf Tf o cn o CO in co o CM CM *-in o o o o o o 3671 ,609 55 1449 CM CO 5782 o CO o o o Tf co o o o O co o 00 in Tf s CD 8 Tf CM T? CM co o co in cn CM 0) Tf o CM LO CD f- CM CM i— h-O CM co o O o O CO in o o o O m oo o o o cn Tf o O o O Tf co o o o o CO o o o o r- r-o o o O o O o in f» co co h-CO co 8 CM o cn Tf o o o O Tf o o o O o O o oo m o CO o O co Tf o o O o Tf o r~- o o o o o o CD o o O o CO o co h- o in CM o Tf CD o o o o CO co o o o o CO in in in CD CM Tf co fi CO in Tf o CO o h. CO r-. CM CD CO tn 10 Tf *- o co O o Tf m o o o o ID Tf o O O o Tf 1 Leachate Volatile Fatty Acids Distribution (mg/L) 1 co co cn co CO CD O CM CM cn ID CO CO co CM Tf *- o o CM CO CM Tf o CD CO 1 Leachate Volatile Fatty Acids Distribution (mg/L) 1 CM Tf CO Tf O O 0) o o o o CO co o O O o co 1 Leachate Volatile Fatty Acids Distribution (mg/L) 1 CM o in oo CO CM oo CO CM Tf co CM Tf f- CM lO 00 o co CM CO o Si 1 Leachate Volatile Fatty Acids Distribution (mg/L) 1 VFA Type 1 Acetic 1 Propionic I Iso-butyric I Butyric I Others I 1 Total 1 I Acetic I Propionic I Iso-butyric I Butyric I Others I Total I Acetic I Propionic Iso-butyric 1 Butyric Others | Total 1 Leachate Volatile Fatty Acids Distribution (mg/L) 1 Column* 1 Date 3/1/95 3/15/95 3/29/95 Appendix F. Leachate Characteristics Data 274 F.4 Chemical Oxygen Demand co 42140 31488 16439 13298 10430 7640 6796 8726 7875 7036 7187 4285 2813 3410 1688 co cn LO r-o> m oo m co in oo in 0) oo in m oo T— Tf in co co oo Tf h-Tf co CO Tf CM tn f~ CT o Tf oo CT CO Tf r-3 Tf LO co Tf Tf CO co cu co Tf co o o 3 CO CO 0) LO Tf oo co co CO 8 in Tf co O) oo cn 10 LO oo in o to co h-fS o CO s o h-LO CO cn CM 5> co Tf o h-co m o oo to CM oo sl co to f-CM Tf o CT CM co oo CO o Tf o ai CO cn to h. 8! cn in Tf co CM CO CM Tf Tf 00 CT CM CO O h. cn io co f-O) o CO Tf 00 o CO Tf CO co co co o oo o Tf CO in CM co r-. oo co r-CO Tf o ft in oo co cn CO o CO CO Tf cn CO co Tf to LO cn f-CM I«-cn cn cn CM LO m Tf o h-CM oo m oo Tf co co to Tf o oo h-10 LO CT m cn Tf CT CT Tf in Tf LO CO to Tf LO f-o Tf f--Tf r-co 0) r-Tf h. Tf CM m Tf co LO 3 oo LO O) O) f-CM R Tf cn co co oo o CM co o O) LO in m oo CO CM co m o Bi co co Tf Tf CM to o r-m oo r-CM OO Tf CO co to 10 CM co f-LO co co co m Tf co o Tf LO CO O Tf co Bi co CM CO o CM CT CM OO Tf Tf co oo CO 00 f--to rr Tf Tf 8 Tf L0 a ft Tf (0 CO CM 8 co o CM § IO oo h. o 3 m CO co 00 S> co in o CO 00 r--Bi co in 00 CO h-o h. in in in cn oo co r-cn co to CM m 00 Tf fl LO OO CO r--co in oo o co co r-. o m f-CO FI CO in 00 to oo in CM m Tf co 00 m o in in CD co O Tf CN Tf Tf co Tf CO co CM CO o SJ 3 CO CM CM Tf oo Tf 0) in CO h-cn CO o Tf Tf co cn CO m CO co co o Tf oo Si Tf 8! cn CO ft co CO f-. CM to to 00 o Tf CO CO Tf R co CO CO Bi co CO 00 Si CO in cn oo CM c-oo CM to co CM Tf LO o CM o co f-[•-m in CM co oo m o oo in co co i— co oo in co oo CO C\J i— co r-co CO LO f-co co r-LO LO f". O CM 00 CO Si CO co in CM i co cn r-co m LO CO oo LO r-oo h. Tf co oo r-oo FI in CM co Tf co f-O) CO f-oo Tf CM Tf CO m co CO Ol o co Tf o Tf m cn m Tf to Tf OO oo Tf f-cn co Tf f-Tf CM oo CM co CM oo in co o co oo o CM *-CO h-CO f-co Tf r-Tf O) LO CO Tf CM Tf P: 00 o in 00 o CO cn o CM o 8 S O Tf 5 CM co cn cn CM r-f-cn o Tf LO CO co CM Tf cn co co CO Tf CM Tf co O) Tf co CM o o in CM 00 oo oo CM in IO to co oo Tf o co CO co m h-m CM h-CM B! co CM 00 co Sj o CT h-CM h. o o CO Tf s Tf f-CM in co Tf CO co CM CO o CO o Tf in co CO Tf CO o Tf oo CO o CO cn cn CM 1 CO co co Tf CM CO f-co LO m 00 00 m m co co CO f-CO Si co h-Bi co o m Tf o LO CO O) Tf Tf CO Si CO $ Tf o oo co CO Tf CO CM CO in CM CO Tf co Tf CM Tf in to o cn co in o CO CM O) CO Tf f-lO 8 Tf CO 00 £ co in CM 8 o CM co LO CO co oo 0) co oo CO Tf cn CO CO LO Tf co CO co o> in o ft LO oo in o co CO 00 oo I-. o to Tf oo CO h-to h-to in co f-LO CO in co 00 cn 00 to r--00 LO y— co co Si o CM LO co to to LO Bi Tf Tf in CO co o co CM oo CM CO Si o cn FI T— co B! CO CO CO LO co CO CM Tf Tf CO CO h-co in CM in co CM Bi CO cn CO LO cn co co in LO co 00 r-Tf co CO CO O) oo 00 Tf 00 LO 00 oo CO cn oo co m cn CO to CD CM CO Tf s Tf O 8 co o LO o o> OO r-co Bi co CO Tf 0) r-CO cn m to TJ h-O) CM CO CO CM 00 Si o o co O) in Tf Bi co co O co OJ CO CM in Si 0) Tf h- f» FI 1— LO CO CO oo co Tf 00 O) co in CM i— CO oo in OO 00 in cn in r-. CO 00 cn r- oo Tf r-CO Tf f>-co oo oo in co f-B! 00 Tf r--CM co Tf CO CM to co CO LO l«-cu in cn co 00 r-Tf o CM o LO co CM to co CM Tf co CM CM CM tn co CT co co o> o CO h-CO co co oo f~ Tf 00 a Tf h-1 CO $ co r-Tf 00 o *— Tf O) Tf co 8 f-CM CO co in in ft 0) Tf B! CO in Tf CO si CO cn in CO 1-to cn CO 00 to s co 00 o co O) CM co I Tf CM 12 Tf 00 h-Tf h-m Bi co CO ft CM o CO CM Tf CM fi o CO CO Tf to co h-00 in in m co s in OO CO »~ in m LO 00 co o LO LO h-co O) r>-Tf Tf co co CU 00 LO CO LO LO CO CO Tf co o m po CO co co oo cn h-in CO oo T? co cn oo oo in in in 0) 00 r«-r-m CM 10 oo o CO Tf oo Tf f-lO f-. co LO oo h-Tf Tf oo co co o Tf CO CO Tf co CO CO o CM m tn o tn CO o CT CM oo oo CO cn co CM oo to oo h-00 CO o h-in o 00 CO h-3 CO oo CM Tf CM Tf co 8 h-Tf oo co CM co Tf 00 CM Tf O) o oo o Tf m co CM o ll h. CO LO LO cn co oo co in CO CM f~-CO CM co co oo oo co co s f-LO 00 in o CO 1 CO CO h- Bi 8 in o 00 Tf ft Tf cn o oo co o CM to Tf Tf r-o co in o cn CM 1 CM r-. 00 CT 00 co r-. o o LO in in CM CT CO Tf co 00 cn r- co cn co 0) CO O LO LO 10 o CO LO Tf 3 CO IV f-CM Tf CO CM oo co *— 00 CO CO co O) in 10 o h-tn 00 Si CO Bi CO CO oo oo r-co CM Tf in CO CO 8 o h-co o FI oo in 8 co to co co CO IO 10 to in N. oo oo Tf m CM Tf cn r-h-co f-oo Bi CO oo o LO CM o o o CM f-Bi CO co 00 ft co m CO co cu in 1— CO co Bi O) CM nand (mi cu CM CO CO CO LO 8 co CO o f-co CM o co CO O) oo co CO LO cn LO h-CO 00 Si o oo Tf 00 s in 00 oo CO to co CM to m CD Tf co co Bi 00 CO CM at Si CO CM ft CO R Tf Tf co CM in co Tf CO CM h-Tf CM oo h- oo to CO c-co in co co co o Tf co o a /gen Dei h-O) O co Tf oo in co Tf LO CO co 00 CM h-co 0> 8 CM CO oo So CO CO FI co oo cn f-m r-oo h-CO co o f-oo 8 co o h-m in CO Tf CO h-Tf Si o LO ft CM co CM in oo oo cn m co 8 in co 9 O Tf 8 co co in oo f» co Tf co co 00 in oo CM in Tf CM CT Bi oo T— CO to oo 00 in o co B! to co 00 CM co r-. to Tf f-co co Leachate Chemical Coo s-~u CD E 1-o Tf CM Tf co in O s oo O) CU 10 CM o Tf Tf LO oo co CM co CO cn o CM co CM m Tf CM to to CM Tf oo CM 00 o co oo Bi co h-m co CT co to T? CT T| CM to Tf CO co Tf to Tf co oo Tf r-oo Tf io LO CM in cn CO in Leachate Chemical Coo c E 3 o O f Co Q co CO o CO s JM O CO s> f". 1— co CO 1 CO po 10 CO 1 1 Tf 1 Tf CO CO 2 Tf CO Tf 8 Tf 92 CO CO Tf 92 CO S! CO Tf 92 Tf Tf 92 1 Tf po m Tf 92 m C! in Tf po CO to Tf go O) CM co Tf go N. Tf 9! o CO Tf po 00 Tf CO co oo Tf go oo | Tf S> co Tf CT 8 to g> LO po 00 ^» 1— in go in 2 in go CM in 92 LO CM in 92 S to go in m 92 cn CM CO Appendix F. Leachate Characteristics Data 275 F.5 Total Organic Carbon CO 11780 6720 4570 4690 3375 2684 3096 3060 2650 2505 1875 1500 1097 CO m rv co rv in 00 in in CO O) o 00 CO CO co o 8 00 CM CO in Tf cn rv 12920 10530 0669 6160 3509 2480 2384 2514 2258 2282 2032 1977 2253 2173 2817 3118 3031 4126 3677 3459 4018 4235 4330 3660 CO o CM cn rv CM |v CM co co CM CO 11900 7210 4910 4840 3168 2218 2322 1971 1329 1139 o rv 0) CO o CO CM rv m o CO CO m CM CO |v in Tf 00 CO o CO Tf rv |v cn o O) CO cn CM m m *~ rv in 12580 9980 6350 5730 3964 2745 2617 2579 2185 2128 1872 1755 1991 2006 2796 3196 3185 4582 3994 3995 4688 5287 5150 4309 rv Si co Tf 14460 11000 7190 6570 4713 3477 3826 3492 3070 3134 2713 1920 1288 CM rv O) o 00 00 605 CO cn CO CO oo 8 Tf co o rv Tf rv CM o CM 00 o CM CO 11720 9160 6120 5760 4118 3330 3802 3869 3316 3457 3108 2640 2536 1892 2122 1545 1457 1428 rv oo 1001 m CM cn Tf rv cn Tf rv rv in co CO CM m CM Tf o CM rv rv in CM 13900 10890 0909 4890 3569 2926 3012 3036 2573 2646 2431 1724 1218 rv CM rv CD CO 00 CM CO Tf 3 CM IO in co CO in o in Tf CO 3 CO rv CM m CO 0) CO Tf cn co oo Tf fv ^ 13670 9430 7590 6480 4821 3835 3968 3693 3489 3799 3504 2693 1873 1223 1286 m Si 0) 1026 co 00 co co cn co in cn 5 co co co in Tf co rv 0) CM cn in m CO in rv in Tf o 13250 9350 5970 5030 3982 3545 4242 4562 4265 4303 3872 3585 3046 2340 2483 1899 1825 1767 1041 1188 co m cn CM cn cn co Si co in 0) in CO o> 13570 9340 5400 4490 3292 2503 CM co CO CM 2507 2214 2056 2008 1913 2232 2341 2942 2871 2487 2503 1678 1429 1092 CD Tf rv cn CM CO co CM CM rv co rv in CM Tf in co 14500 7290 5340 4560 3561 2890 2982 3100 3066 3120 2924 3022 3527 3244 3805 3788 3570 3758 2493 2317 2060 1124 00 rv CD rv CM Tf CO o cn o rv CO in CO CO rv 13660 7900 6030 4820 3138 2554 3000 3022 2547 2460 2070 1735 1612 CO O) cn in Tf <° CO co 0) CM o Si 00 in rv Tf CM co in co co Tf co 12140 9190 6830 5040 3248 2190 2302 2097 rv o rv co CM CM o o co Si co rv 2266 2376 2098 2431 1556 1535 1349 o CM co co co rv 1 CO CM 3 co o CM cn in o> oo in 14820 9560 7360 6020 4250 3192 3446 2861 2295 2175 1944 2106 2824 2459 2913 2724 2345 2632 1930 1959 1893 1363 1012 Tf in p- fv i— cn O) in o Tf CM co Tf 13200 8350 6450 5080 3438 2534 2621 2604 2277 2304 2111 1912 2151 2046 2330 o co oo Tf CM co 00 oo co in rv CM CO CM o in o co oo 00 rv co o> co Tf 01 m co Tf o co co m co co Leachate Total Organic Carbon (mg/L) co 13890 8320 6380 5080 3562 2640 2828 2617 2298 2404 2133 1912 2330 2006 2363 2098 2088 2407 oo rv m in Tf CO in co rv rv co CM co co Tf co o 8 Tf rv Tf rv o co CM Tf Leachate Total Organic Carbon (mg/L) CM 12540 6900 6930 5620 3881 2992 3300 3172 2636 2814 2691 2211 1882 1424 1269 CO Si co |v co rv m CO Tf CO CO in CM Tf CO rv | cn rv T? CO rv fv Leachate Total Organic Carbon (mg/L) 10300 7540 7900 5800 3919 3026 3112i 2983 2419 2453 2169 2082 2344 2028 2350 1959 1996 2030 1375 1435 1292 Tf CM O) rv o cn co o cn CM co co OJ o in CM Tf co CM cn co Leachate Total Organic Carbon (mg/L) Time (day) o Tf to in o rv 3 oo 0) CM co CM o Tf Tf m CO CO CM oo CO O) o CM co CM in Tf CM co co CM Tf 0) CM oo o co 0) Si co rv m CO oo rv CO co o Tf CO co Tf rv O) Tf in in CM in cn co in Leachate Total Organic Carbon (mg/L) Column* 1 Date 10/6/93 10/20/93 11/17/93 12/1/93 12/15/93 12/29/93 1/12/94; 1/26/94 2/9/94 2/23/94 3/9/94 3/23/94 4/6/94 4/20/94 5/4/94 5/25/94 6/8/94 6/29/94 7/27/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 2/1/95 2/15/95 3/1/95 3/15/95 3/29/95 Appendix F. Leachate Characteristics Data 276 F.6 Inorganic Carbon oo o oo 1 o o o 0> CO co Tf in IO m CM o rv O o rv oo CM oo Tf Tf o oo co co co CM 00 rv CO 1 co 0) co m co oo Tf oo rv co co 00 tv 00 oo tv fv o oo o Tf o o co iv o rv co CM co CJ) co CJ) CO m CM Si co in rv Tf CJ) oo CM o o in co o CM co iv o m o rv m Tf CO o oo o Tf o o CM Tf Si co oo CM 0> |v co Tf co co o CO Tf rv 00 CO m O) |v co CM CM CM o 10 CM O 81 co rv CO co in co 5 fv 0) oo co CJ) CO CO o 00 3 CM in o oo o Tf o o CO co in m s CM in 00 rv oo CO in |v CO o 3 co oo o co CM m CM co Tf CM Tf co o CO o co o Tf o o CM rv co rv Tf CM 00 o o co co rv oo o co oo in Tf co Tf m oo CM Tf Tf 0) o Tf Tf Tf tv CM co o o co rv CM CM fv oo co m co Tf rv oo o o CM co o CD o Tf o o CM Tf o rv 00 Tf co in Tf co 00 IV CO rv co O) tv oo CM CM tv 3 co oo m Tf i— CD CM o CM co 8 o rv fv in 0) 00 tv m 0) co Tf IV co CM o oo o Tf o o CO Tf tv 8 O) co rv CM CD co CO o CM oo in i— Tf CM Tf CJ) in oo oo in 00 fv o Tf o co CD CO co oo CM Tf fv CM CO CM CD CO CD m 00 3 ^ o o CM o Tf o o Tf Tf in CM CM oo *- CM CO CD rv 3 % CJ) in m rv 00 rv oo Tf tv CO Si co o m CD CM 00 m CM o fv CO o o co CM CM O CM CO CM CJ) 00 o o CM o Tf o o oo m in in oo in 00 00 in co rv O) 00 CM CO co tv O in fv o co in Tf co o co m rv |v co co CM co oo CO CM CO CJ) §! oo GO CO 81 0) o o CM o Tf o o oo m rv Tf CM co CO CD co 0) CD CM Tf CJ) CO CO in 0) m CM rv Tf *~ o Tf Tf co Tf co o CM co in CM CO 00 CM m oo m CM CM in CO m CM CD 0) GO 81 in CO CM 00 o oo o Tf o o a O CM s o in 0) m 8 CO CM fv o in co CO CM m 00 CO fe |v CO in CD co CO Tf CM CD oo Tf co CM Tf Tf CM CD co |v CM O CM oo CO CM in CM rv o oo o Tf o o CM CM CO CM o oo CM 00 CM 10 co o co CO 0) m 3 in Tf CM Tf in Si 0) o CM tv co co CM Tf co CM CM CM Tf Tf oo o CM 0) CJ) CM CO fv CM tv 0) co CO CD o o CM o Tf •r-o o 9 00 rv CO 1 co oo m oo o m 3 Tf CM rv oo 0) in in Tf tv rv fv 81 O) co CM co co CM Tf co co co oo in o co CM CO Iv" CM Tf fv CM in o oo o Tf o o 8 8 S 3 o co o o CO fe CM oo CD Tf in CM CJ) o CM tv co m IV co co IO Tf co CD m CM oo co CM o CM CO 8 CM CO m CM Tf o CM 1 o o R CM co CM o> rv fv co CM co Tf 3 co co 0) in rv CM tv in oo CM 3 rv 81 CO 0) in co CO CO CM co in in CM Tf Tf CO CM Si 0) O CM CJ) CJ> co o Tf CM o Tf o o 00 CM O co CM § oo m Iv co 0) CM 0) oo 0) m m fv o o> 0) O Tf co co 81 CO in CO fv CM co m CO CJ) 0) u in Tf CM 5 CM fv Tf co CM Leachate Inorganic Carbon (mg/L) CM o Tf o o Tf CM 00 in CM o o oo |v CD CO co co 3 3 CO in CO o o oo o Tf Tf 0) CD 00 00 o CM rv oo o o CO o 0) CM CM CO co Tf tv oo CM co |v 0) CM CO oo CM O CO CM 8 co Leachate Inorganic Carbon (mg/L) o Tf o Tf o o CO CO CM Tf rv CM 3 fe co m CO m co co oo Tf tv in o o co co Si co O CM co co CM Tf co oo 0) 0) o o CM oo o CM CM co O fv co Tf CM |v 00 co 0) Leachate Inorganic Carbon (mg/L) I CD E I-o Tf co in O rv 3 oo 0) CM CO CM Tf 3 B! oo 8 o CM co CM m CM CO CM Tf oo 8 O) Si CO tv m co oo fe co T? CM T? CJ) CD Tf co GO Tf fv CJ) Tf in IO CM IO 0) CO in Leachate Inorganic Carbon (mg/L) % C E 3 o o 1 Co o co 9! CD o co 9! o co g> tv co 9? co cn IO co g> 0) 1 Tf 92 co 2 Tf co CM Tf 0) § co Tf 9! CO CM CO Tf 9? Tf Tf i CM Tf Tf 1 m Tf ? in CM m Tf ss co Tf 0) Si co Tf Tf CD tv CM fv Tf 9! o 00 Tf s 00 Tf 92 oo CM CJ) Tf CD CD o Tf 92 co '— in S IO 9! oo in CD 5 in 92 in CM in 92 53 in 9? m CO in 92 0) co Appendix F. Leachate Characteristics Data 277 F.7 Alkalinity co 8440 7520 3560 2760 2560 2040 2180 1820 1940 1220 1300 o CD 0) in CD 00 o Tf tv o oo co o co co o CD in o in o LO o oo Tt o co Tf o SI in co o Tf o Tf o CO o CO o m CD in 00 m cn tv o o CVI co o cvi cn o Tf co Tf T? 8 o Tf co CM o o co T? rv o o Tf o co Tf o o 0) o Tf cn O CO co m 5> O O 00 o CO m m CO o o CO oo o CD 00 CO CD 0) o 3 o 8 i m CD co in CD co o in co m cn o Tf o CM in CM o o o CO o o CO 00 o Tf in oo o o |v CO o oo co CVI o CVI co CVI o oo co o | o CO o o Tf o o co rv o o 00 o Tt co o 0) co o co co o o co o cn m m oo Tf o LO o CO o 0) Tf I o fv CM o CM o o CM o o CM in cn in o CM in o CM o o CM in m o co LO o Tf co (0 o Tf <o rv o CVI 3 o co in cvi o Tf Tf cvi o CO co T? Tf o o CM o Tt CM o o o oo o o CO o CO oo 8 rv T? Tf in in co o m in o CO in m o in § O tv to o co Tf o to o Tf Tf Tt o Ti to o o Tf o o CVI CO Tf o o Tf co o co Tf CVI O o Tf CM o oo oo o o CM 8 co o Tf O) o co tv in m Tf m m CM o CO CM o CM o 81 8 CM 8 1 O O CM o in m CO 8 8 8 o in in Tf o co in to CO o o o CD o co oo 0) O o o co co o co CO o co LO CM O 3 CM o o CM o oo CD o 3 o Tf o 3 o o rv m cn co o CM o co CM o Tt O co o Tf o CM o co O CM in co in CO in CM CM in CO o o in CD o CM CVI o o CO 0) o (0 O co in Tf o o CO o 8 cvi o cvi co CM O CO CO CM o o oo 8 cn 8 CO o 3! 8 oo o CM m o CM o CO O Tf o Tt in CM o in O fv o CO m co o co o co o |v in co in Tf o m o Tf o in Tf o (O in 0) o o CVI o in o Tf o Tt o s CO O O O co O s CM o o CM LO CM o CO rv o ft! CD o co CM o CD O to o 00 CM O CD CO o cn CM m co CM m CM o co o oo in o> o CM o o CM m cn in tv O co o co CM o co in co o in o o CVI CO cn o o o o o Tf o Tf o Tf o CO o co co o 8 CVI O Tf CM o CO CD o 00 0) o o 00 O Tf o CM co m 00 rv o CO Tf o CM O co CM o oo o Tt o co o Tf o in o 0) o cn in o CM in in CM O) o o tv CD o 00 Tf o o o o Tf § O) CM o o CO cvi o 8 CM O co CD o o co o in m o o T O 00 o o CD in co i— o in o O 3 O 8 o oo IV o fv to o o fv o r^ o cn tv o CO oo o CO fv o Tf IV o m in in o 3 o cn CM o m CM in 81 o co CM co O O rv o 8 oo o co co co s oo CVI o 3 CVI C^ co CM O 8 CM I o o co CM o co co 8 rv o cn Tt o cn cn in Tt rv o 8 o oo co m 0) Tf o m CO o 8 o cn o 8 o 00 o 00 tv o 15 o m Tf m 8 o 3 m CO co in tv CM CM o CO CM f- o Tf (0 cn o oo Tf o T-o oo cvi Tf o co o CO o CVI rv cvi O Tf 81 O 3 CM o 00 0) *— o co o CM o 3 o 8 o co CD o 5> o |v co o 3 o CM in o m in o 3 o 3 o In o m to o o CO o 00 in in CD Tf o T? O CM Tf CO o co o o s o o co Tf o Tf o co o cvi o o cn O Tt rv o o o in 1 o 8 o co rv o co o CD o o rv to o tn o o cn 0) in 3 in o cn o CO tv o tv 0) in 3 in 8 o to o o cn o IO co o in o cn co o Tf Tt m CM O co CM LO o Tf in 0) o o Tf cn o co in Tf o o o BJ CO o o co CM O Tt 81 o oo co o co in o Tf o CM o co o o CO r— O CO O tv co o oo o tv cn o fv cn o o o fv 00 o Tf cn in cn cn in Tf oo in 0) oo o co in o fv Tf o co Tf in oo co o m co o o co O 00 CM Tf Tf CD o (0 cn CO o o o Tf o Tf o CO o CVI 00 CVI o 8 CM o Tf o CM o o Tt co o Tf O o oo cn in in tn 0) o co m m to o in Tt o co co o co co o oo CM o |v CM o o co o to o fv to m cn CM in fv CM o CO CM o 81 o CM o 00 O cn CO O (0 Tf CD o o s o 8! CD CO o CVI 85 o Tf oo cvi O co o CM O O CM o oo o CM o o co o Tt CM CM co o Tf o m 00 in co o o oo in m ft! CD o in fv o co tv o 8 O to Tf O CM Tf o co Tf o oo CO m co co o cn CM O co CM o o CM LO CD o o CM o oo o oo Leachate Alkalinity (mg CaCO-3/L) cvi O O O 00 o Tf Tf |v o co Tf o o cvi CO o oo o> CM O O LO CM O 3 CM o o tv o oo co O CO T o CM co o Tf cn o 0 01 o cn to o co CO O co in o rv Tf o 3 o tv CO o CO IO O to o 8 in tv in o 3 o in CO CO in 3 O in CO o Tt CO in to CM o cn CM Leachate Alkalinity (mg CaCO-3/L) o Tf o rv O o Tf CO o o oo Tf o o 3 o 8 co O CO Tf CM O 00 81 o o oo o co tv o o CM o o Tt o co cn o CO o o 3 o o in CO O cn to o CO CM O 81 o 00 O 00 o oo o o m o in in CM o o in CM o CM o in Leachate Alkalinity (mg CaCO-3/L) XI CD E i-o Tf cvi Tf co in o tv Tf 00 oo cn CM co CM O Tf Tf m co CO ft! co co CD o CM in Tt CM co co CM oo o co CD ft! co tv m co 00 rv CO co o Tf co Tf Tf CM CO Tf cn CO Tf co |v Tf co 00 Tf rv CD Tf LO in CM in cn CO in Leachate Alkalinity (mg CaCO-3/L) % c E 3 o O fi Q co a> co o co CD 0 1 co 9> rv — co 00 9> LO co CD cn § Tf 1 Tf co Tf Tf CD CO CM Tf co Tf 9? co CM CO Tf s? CO Tf Tt S» o CM Tf Tt CD in Tt 9? oo CO Tf CD cn co Tf 9! o 00 Tt 9! CO 00 Tf CO S! 0) Tf 9? cn —. o Tf CD co —. Tt 9! co § in 9? in oo in 9> in CM m 9> in 9! in CM in 5? 55 m 9> in co in cn CM co Appendix F. Leachate Characteristics Data F.8 Specific Conductance CO co co oo o> o oo co |v y- cn oq cq in CM cn co oo oo co co CO CO CM CM CM CM CM Tt cvi cb Tt Tt CO c\i cvi cvi d d d d d d d d d d d d d d iv Tt co cn o Tt CM CM CM tv cn co co fv T— m |v at cn at Tf o co cq oo in Tf LO Tf CO Tt Tt 00 iri co' CO CM CM cvi cvi cvi co co co co co co co cvi d d d d d d (O |v r- y- Tt co tv CO cq CM CO co co Tf CM q cn oo co co Tf Tf co Tf Tf Tf Tf co co CM Tt CO |v' Tt co' cvi d d d d d d d d d d d d d d IT) CO CO CM Ot o cn o y~ co cn Tf co y~ LO cn o *- o in o tv in Tt Tt tv Tt co CM cvi cvi cvi cvi cvi co co Tf Tf Tf' CO co cvi cvi cvi CO LO tn y- CO o o y- Tf Tf CO Tf CO tv co Tf Tf Tf Tf Tf CO co co co co co co CM co CO CO oo CO Tt Tf' CO co cvi cvi d d d d d d d d d d d d d d d d co W co co oo m T- i- cn CO Tf CM cn fv Tf cn co fv co co co co m Tf Tf Tf co CO co 10 LO od iri Tt Tf' co cvi cvi cvi cvi d d d d d d d d d d d d d d CM tv in CM oo CO 00 oo CO y~ Tf q fv co LO Tf Tf Tf co co co co co co co co CM co co CO od iri CO co' cvi cvi cvi cvi d d d d d d d d d d d d d d d d y- o co co tv 00 Tf in co y- cn CM oq fv co q y- tv co m in in Tf Tf Tf Tf Tf co co co co in cri cd Tt Tf co' co co cvi cvi d d d d d d d d d d d d d O o y- CO oo o 0) m Tf co oo m Tf o CO Tt q tv tv fv co co co co co iri iri tv iri iri Tf co CO cvi cvi cvi cvi cvi cvi d d d d d d d 0> LO Tt in cn CO Tf m m o Tf o o CO CM o tv cq in Tf co at oo co in in Tf Tf iri in tv Tt CO CO cvi cvi cvi cvi cvi co' CO cvi cvi cvi d d d d d d d 00 LO in y- Tt o 1- Tf co tv CM cn CM o O) oq IO cn CM oq in co co oo tv co co in m Tf cb co |v iri Tt Tf co co cvi co co Tf' Tf' co y— co cvi cvi y— y^ d d d d d d d tv 17.0 14.2 tv tv OS CM Tt Tf cn cvi tv cvi co cvi co cvi cvi tv in q q cn q q q at d co d oo d cn d CO LO in Tt o O CM o cq cq CO fv CD in in cn o cp y- at cq cq in CM at co fv in m CO Tt od iri co CO cvi cvi T— cvi cvi cvi cvi cvi cvi i— cvi i— y— y-^ d d d d d LT) O o in cn CM co co CM CM co oo o cn 00 Tf fv LO CM o cq cq in T- q oo fv fv co in IV iri cb iri Tt co cvi cvi CM cvi cvi co cvi cvi cvi cvi cvi cvi d d d d d Tt U) CO oo CO iv CM in Tf 00 Tf Tf tv in CM 0) CO q at co fv tv Tt in Tf Tf Tt CO Tf CO Tt tv' iri co' CO cvi cvi T— cvi CM CM CM cvi y— T— T- i— d d d d d d d d d d d CO o CO tv Tt |v in m Tf T- in co fv co co in o fv IT) iq CO q rv CO in Tf Tf Tf Tf co Tt tv iri CO CO cvi cvi cvi cvi cvi cvi cvi cvi cvi cvi d d d d d d d T— E CM CM T-cn Tt oo tv oo Tf co co oq Tf Tf y- q q q q q q at tv tv co co m in m co E. iri CO r-00 iri Tf co cvi cvi cvi cvi cvi d d d d d d d d 8 Tt 0) oo CO o tv tv co T- 10 CO CO Tf CO y- Tf q cn co co oo in in Tf CO CO CO CO ductan co CM od iri Tf co cvi cvi cvi cvi cvi cvi cvi cvi cvi d d d d d d d d d d d Com o Tt o fv co cn CM CO CM o Tf s CO co Si co CO at o CM in Tf CM CD CO CM § co at Si CO tv m CO 00 tv co CD o Tf CO CM co Tf cn CO Tf CO tv Tf tv cn Tf in in CM m cn co in Leachate Specific Time (d Leachate Specific i Column # Date 10/6/93 10/20/93 11/17/93 12/15/93 1/12/94 1/26/94 2/9/94 2/23/94 3/9/94 3/23/94 4/6/94 4/20/94 5/4/94 6/8/94 6/29/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 12/23/94 1/11/95 1/18/95 1/25/95 2/1/95 2/15/95 3/1/95 3/15/95 3/29/95 278 Appendix F. Leachate Characteristics Data F.9 Total Solids 279 00 32952 25064 12112 9442 7902 7146 6446 5792 4990 4096 3410 2868 2454 2030 1294 1216 CM cn co co co o oo r-Tf Tf r» co Tf o oo CM co f-CM 00 CM CO CM Tf SI 00 CO CM CD CO CD h-31992 33068 16682 10648 8270 6256 4976 4616 4046 3498 3300 3740 4078 4360 4932 5490 6182 6286 6472 6078 5240 4517 3982 2246 1242 CM O cn o CM co CO CO in co co Tf co 33588 27470 12220 9628 7192 5946 3990 3242 2856 2546 2152 1980 1742 1758 1286 1330 o cn Tf oo CM m oo CM co r--CO co ID CO oo co o in CO 00 CM CO 00 CO CO o CM CO ft) cn CM CD SI 3 CM ID 28298 28912 12838 12098 7166 5416 3916 3718 3356 2786 2660 3078 3430 3960 4636 5374 6040 6342 6402 6040 5220 4267 4074 3618 3500 3400 3300 3200 3100 Tf 38512 37344 16114 11868 9772 8476 6562 6098 5774 5072 3834 2562 2090 2012 1106 O) co oo IO 90S co Tf Tf co oo co co co co co co o o CO Tf f-. CM Tf 00 CM CO o CO CM i to Tf CM 00 33752 33234 14870 12062 9884 9036 7396 6426 5632 4684 3954 3348 2862 2466 Tf in oo 0691 o CO CM CM CO Cj o CO oo Tf oo 00 in rv CO o h-CO Tf in CO o in CO co Tf O co CO o CO CO 00 CM CO CM 36126 37704 14594 10546 8526 7388 6230 5782 5372 4564 3368 1996 1472 1308 oo co co o m r-o Tf co co f-in Tf Tf in co oo Tf Tf in Tf cn co CO oo co CO CM o CO CO CO CO 00 r-CM CJ! in CM CM 35738 33512 18196 13710 11492 9726 7858 7546 6972 6454 5094 3412 2688 2444 1754 1400 1526 co oo Si co 00 o FI Tf CM CO cn co CO m CM 8 Tf 00 CO CO 3 00 Si co o 35014 34460 13978 10280 9932 9254 8336 7636 6370 5470 4802 4118 3558 3090 2356 2014 1566 1292 1108 o co cn oo co oo s r-o CO f-CM h-o o o oo co o co co o 3 o CM CD CD 36548 36182 13698 9678 7890 0969 5482 5068 4580 4046 3726 4280 4884 5112 4242 3852 3436 3320 2294 1766 1446 1272 1180 Tf 5) s 00 3 Tf cn Tf Tf CM Tf 00 40496 25052 12018 9496 8176 7340 6206 9999 6350 5812 5850 9099 7062 7232 6866 6504 5856 5198 3504 2408 1776 1464 1354 3 cn o in h-Tf 00 co CO Tf m o h-Tf 3 Tf r-35220 28770 13440 9788 7646 7340 6568 6048 5278 4394 3558 2988 2404 2098 1466 1162 o> 1002 1014 co Tf oo o ft! 00 oo 00 co r-f-. o Si co o o oo o oo f-. o co f-o Tf h. o Si CD 33006 30220 15212 10516 7762 0009 4436 4304 3634 3044 2826 3680 4054 4430 3994 3984 3832 3750 3362 2758 2728 2262 2172 1594 1250 1010 Tf o CO CD CD m o tn in 37824 33278 15816 12124 9538 7634 5462 4738 4092 3620 3842 4606 4948 5062 4544 4608 4636 4210 3572 3002 2508 2182 2086 1366 1034 Tf ft! CO o f-CD CM CO o oo m Tf 36036 31718 13298 10430 8326 6800 5206 4982 4424 4000 3752 3834 4062 4022 3016 2836 CO 3 co CM O Tf CM co CO co o m oo i Tf in co o in o oo Tf CD CM Tf CD in co CO CM co co 34604 29614 12700 9682 8278 6818 5354 5304 4822 4446 4260 4276 4230 4300 3914 3878 3218 2788 2214 1932 1736 1395 1242 1 o oo co o o CO 3 co tn Tf Tf Leachate Total Solids (mg/L) CM 32618 25336 14014 11238 8936 7524 5654 5168 5060 4582 3860 3474 2964 2684 2004 1480 1096 1068 1022 co cn o oo oo 00 oo o 3 co oo co Tf 00 in Tf oo in co in in Tf tv Tf O co Tf Leachate Total Solids (mg/L) 28464 28906 16780 11934 9186 7846 6140 6024 5112 4524 4154 4174 4042 3860 3338 3116 2052 1698 1394 1232 1164 h-00 oo CO CO o 3 o h-m Tf CM in o Tf Tf O to co Tf co Leachate Total Solids (mg/L) Time (day) o Tf CM Tf CO in o h- Tf CO CM CM o Tf 3 oo co CM 00 CO CO o CM m Tf CM co CO CM co o co oo CM CO in co co h-co CO o Tf CO Tf Tf CM co Tf oo co Tf co h. Tf s Tf in in CM in cn CO m Leachate Total Solids (mg/L) Column # Date 10/6/93 10/20/93 11/17/93 12/1/93 12/15/93 12/29/93 1/26/94 2/9/94 2/23/94 3/9/94 3/23/94 4/6/94 4/20/94 5/4/94 6/8/94 6/29/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 Tf 8 1/11/95 1/18/95 1/25/95 2/1/95 3/1/95 3/15/95 3/29/95 Appendix F. Leachate Characteristics Data F.10 TKN 280 co 255.5 386.1 192.0 169.7 81.7 84 0| 59.3 48.9 41.0| 38.5 42.9 27.7 19.7 15.8 o Tf |v Tf oo od od 14.7 LO 0> Tf Tf 46.0 co co co Tf co UJ r-509.7 565.6 335.5 245.0 123.7 93.6 68.0 53.8 45.0 36.2 37.5 34.9 45.5 49.7 57.2 53.0 78.1 80.4 93.2 76.1 79.0 83.9 to co' 56.9 15.1 CD CD cri uj <o 255.0 359.2 161.0 117.3 51.4 47.0 27.6 29.3 33.6 24.4 CM |v CM r-' co |v CM 00 co Tf o CO LO cri 10.8 o> LO CM CO Tf CM Tf cvi to CO 21.1 CD 6 to cvi CO 14.3 LO 847.8 1079.8 508.7 398.9 254.7 194.5 141.7 114.2 93.9 62.8 47.2 61.0 65.1 74.1 73.8 85.4 93.8 94.8 125.0 98.9 126.9 119.7 77.8 17.7 47.4 Tf 468.0 826.1 438.6 314.0 182.9 134.8 91.0 74.8 66.7 43.2 22.9 11.0 15.8 10.3 CM to 14.3 o> od CO Tf CD cvi co co" CO cvi Tf Tf Tf od CM CO Tf o Tf Tf CO 404.4 560.3 278.2 213.5 97.5 63.0 41.1 25.5 26.8 32.4 28.2 co cri o cri co Tf CM 00 cri CO cvi CD |v CM io' CO Tf |v co Tf CD 00 CO tri O Iv tv |v |v to' CM 650.1 641.8 280.8 187.1 75.4 69.9 47.6 37.4 33.8 27.5 17.3 o cri o> IV CO LO O) CO CM id CD to' 11.6 CD cri in CO LO co UJ cvi Iv CO O) Iv co' CM tri oo Tf CO d 666.9 720.9 379.6 283.4 146.2 130.0 84.3 49.1 60.5 48.4 34.9 21.0 to' O O) oo IO 14.2 10.4 o 6 17.2 co Tf LO UJ cri 00 od CD rv Tf o> tri 00 cri CO cri o 438.5 1035.2 272.6 199.8 105.5 88.1 54.2 38.0 38.2 36.2 33.9 29.6 28.0 23.0 17.2 19.5 19.3 16.6 16.4 10.1 |v cd 13.3 12.2 CM cd to cd co 385.9 401.2 199.8 177.6 62.7 49.0 34.7 18.2 15.5 15.7 10.5 16.0 20.0 20.7 15.7 20.0 17.5 27.9 23.6 21.0 18.8 17.2 12.1 22.5 O) tri 13.5 co tri CM cvi co 456.8 621.3 228.9 247.8 176.1 135.5 98.4 91.0 90.4 51.0 47.9 54.4 57.1 57.3 42.8 42.1 36.4 43.5 33.9 27.0 27.9 28.7 22.5 Tf 15.1 10.9 |v tri CM |vi f-964.2 789.8 200.0 226.0 125.3 93.4 48.4 36.5 28.5 33.4 20.7 25.9 21.6 21.4 12.3 16.2 15.6 17.4 14.0 12.4 |v cri 10.5 *— cd 18.9 iri (O 437.1 625.0 362.7 254.0 144.3 100.6 77.4 54.0 55.6 28.3 20.6 20.5 17.7 18.7 20.1 28.5 23.8 35.3 30.2 26.3 26.1 29.8 21.9 15.8 16.7 15.8 15.3 co od LO 874.8 958.5 354.7 256.6 165.9 146.1 114.4 89.7 68.8 47.5 30.4 38.9 46.0 50.0 43.0 46.5 40.2 32.0 31.2 17.1 16.7 17.7 13.4 CM 00 UJ 00 oo |v to CO co Tf Tf 521.2 574.9 331.0 245.1 121.4 98.5 66.2 909 50.4 49.7 39.8 40.8 32.8 30.2 17.0 23.1 17.3 23.4 21.5 14.1 16.5 22.4 18.8 10.1 CM tri CD Tf CO tri CO CO co 1013.0 1122.8 471.5 305.7 177.8 124.5 86.1 64.0 53.9 30.8 40.6 31.2 32.3 31.2 26.7 33.2 28.4 33.1 38.6 25.4 22.1 15.1 12.3 11.9 co od Tf |v CM 09 CM 824.5 877.8 395.7 317.4 200.0 168.4 131.9 102.7 83.9 35.4 62.2 43.3 25.2 16.5 12.5 16.9 10.7 o CO LO od 11.7 UJ cd co tri CM cd UJ cd IV cri OJ CO Tf cri Tf Tf Leachate TKN (mg/L) 614.7 702.5 351.5 237.2 130.1 89.0 59.6 30.1 30.2 30.0 23.4 22.4 22.4 22.6 15.6 17.6 16.3 16.6 15.6 15.2 o CD tv cri 13.2 12.1 CM 00 CO od to iv1 |v iri Leachate TKN (mg/L) Time (day) o Tf CM Tf CO LO o Tf co co o> CM co CM 3 co CO Si oo co CO o CM co CM 10 Tf CM co co CM Tf O) CM oo CD CM CO |v 10 co 00 r-co co o Tf CM co Tf CD T? co IV Tf co 3 |v CD Tf Leachate TKN (mg/L) Column # 1 Date 6/10/93 20/10/93 17/11/93 1/12/93 15/12/93 29/12/93 12/1/94 26/1/94 2/9/94 3/9/94 3/23/94 4/6/94 4/20/94 5/4/94 5/25/94 6/8/94 6/29/94 7/27/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 UJ 1/18/95 1/25/951 2/1/95 2/15/95 Appendix F. Leachate Characteristics Data 281 F.ll Ammonia Nitrogen CO 142.5 247.3 152.4 107.2 77.9 53.5 53.5 17.1 17.5 Tt crj cp 90 CO d CO d co d CO d 272.5 289.4 206.4 151.2 103.3 63.5 63.5 19.5 11.5 23.7 28.3 26.3 32.2 37.4 43.4 40.0 30.3 22.3 co 145.0 244.9 144.6 86.4 48.6 24.0 24.0 iri co CM rv rv d CO d in d SO co d CD in 417.5 459.2 291.0 272.8 202.9 135.5 89.1 60.0 41.0 42.6 40.7 46.4 52.3 56.8 61.0 57.9 45.0 14.2 Tf 242.5 392.9 290.3 206.4 151.2 95.6 53.7 29.3 10.6 0) in CM SO d d o d o d o d co 231.3 326.5 190.5 138.6 83.3 34.0 10.7 in iri CO Tf Tt csi rv cq CM cvi o Tf' cvi co d 90 oo d CM 335.0 356.2 209.3 133.7 75.3 40.3 22.3 15.1 rv rv' cvi co m CM q co d O) d CD d SO ^ 360.0 384.1 239.5 194.7 140.6 90.9 41.6 32.1 15.51 co cvi Tf CM rv CO co d CO d SO CO d o 227.5 304.1 192.8 133.2 81.7 48.0 11.1 10.1 rv cd rv iri CM CO CO CM cn cvi O) d O) d Tf m iri 0) 222.5 243.0 172.5 114.7 74.1 42.2 25.2 CO co co CO rv Tt co Tf Tf CM CO CO co CM cvi o cvi GO in co 290.0 449.4 231.1 183.6 156.1 115.3 72.8 46.9 28.2 32.0 11.5 CO rv co co rv' CM Tf' CO co cvi tv 475.0 421.6 255.8 180.6 119.6 74.0 26.8 12.3 11.2 15.2 0> CO in iri m rv CO Tt o CO o co' 00 CO cvi co 252.5 356.3 254.0 185.1 123.3 81.4 57.4 29.4 CM co rv Tf O) cd CM iri in iri co in CM Tt IO cvi cn co m 372.5 405.0 219.4 179.6 144.5 104.4 69.0 39.1 24.9 26.3 28.6 14.7 11.5 CO O) CO Tf co cvi o cvi 00 d Tt 277.5 352.6 237.0 162.9 116.6 71.4 47.4 31.4 28.9 21.2 tv rv fv co 10.2 11.4 0> CO CO CO 12.3 Tf cn CO 470.0 i 316.7 211.3 144.8 90.4 61.8 22.6 12.7 13.7 10.8 rv 0) 15.4 16.9 12.5 in co o CO CM Tf' Leachate Ammonia Nitrogen (mg/L) CM 397.2 421.8 272.5 211.5 161.9 122.3 78.5 52.1 45.2 16.4 CO CO (v d co d SO o d q Leachate Ammonia Nitrogen (mg/L) 307.5 334.3 231.0 150.2 91.7 54.9 22.7 13.7 10.5 co co rv Tf m Tf' o> iri rv co Tf iri co cvi Tf co' Leachate Ammonia Nitrogen (mg/L) Time (day) o Tt CM Tt CO m o rv 3 CM o Tt co CO CO 0) m Tf CM co co CM Tf co o co CD si co tv in co 00 rv co CO o Tf Leachate Ammonia Nitrogen (mg/L) Column # Date 6/10/93 20/10/93 17/11/93 1/12/93 15/12/93 29/12/93 26/1/94 2/23/94 3/23/94 4/20/94 6/8/94 6/29/94 7/27/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 Appendix F. F.12 Zinc Leachate Characteristics Data 282 00 2.42 2.40| 2.44 2.32 2.001 2.40 2.30 2.361 2.20 1.96 1.40 1.10 0.78 0.52 0.42 0.14 0.28 0.10 0.06 0.06 0.04 0.08 0.01 0.00 f-1.74 2.80 2.08 to p Tf oo to CM Tf co to o oo co o to Tf to o t-; Tf h; o oq 2.02 Si co Tf oo co cq r-to ID 1.20 0.80 0.36 0.32 0.32 0.36 0.40 0.20 0.18 0.16 0.14 0.06 0.04 0.08 0.16 0.02 0.04 0.06 0.02 0.02 0.04 0.08 0.00 0.00 LO 21.20 j 10.80 4.16 3.26 2.86 2.62 2.22 2.10 2.00 1.78 1.52 1.56 2.02 2.88 3.42 4.28 5.80 5.74 6.54 7.00 10.14 9.94 4.40 2.40 Tf 0.88 0.80 0.32 0.24 0.28 0.27 0.32 0.18 0.24 0.36 0.24 0.14 0.18 0.20 0.26 0.06 0.14 0.10 0.06 0.06 0.08 0.12 0.04 0.00 CO 2.00 2.80 Tf to to CM Tf co Tf LO Si 2.24 2.42 2.44 2.18 2.06 Si 0) Tf oq Tf to to co Tf co to p 0.96 0.96 0.82 0.80 0.68 0.41 CM 3.14 2.00 0.92 0.88 0.86 1.34 1.56 1.66 2.28 2.66 2.96 2.24 1.74 1.36 1.40 1.00 0.96 0.80 0.80 0.68 0.42 0.42 0.29 0.14 ^ 1.62 1.60 0.48 0.36 0.34 0.41 0.46 0.38 0.56 0.66 0.60 0.58 0.36 0.40 0.40 0.32 0.38 0.36 0.40 0.48 0.32 0.38 0.21 0.12 O 3.58 3.601 3.16 2.26 2.58 3.18 3.78 4.06 4.04 3.66 3.14 2.90 2.34 2.44 2.18 CM o> CM Tf CD CM o CO 0.98 0.86 0.59 0.33 0) 8.38 7.20 3.88 2.76 2.50 2.40 2.34 2.20 2.22 2.08 1.90 1.80 2.10 2.80 2.88 2.60 2.22 1.58 1.28 1.10 0.64 0.28 0.13 0.01 oo 2.54 1.60 0.72 0.56 0.54 0.53 0.50 0.46 0.64 0.56 0.58 0.68 0.76 0.88 0.88 0.80 0.96 0.82 0.74 0.74 0.52 0.38 0.23 0.01 f-0.48 0.40 0.28 0.04 0.06 0.07 0.10 0.00 0.22 0.24 0.20 0.18 0.08 0.10 0.02 0.04 0.04 0.04 0.04 0.04 0.16 0.03 0.00 (0 10.14 5.20 2.16 1.38 1.06 0.99 0.88 0.90 0.86 0.74 0.66 0.76 o p to Tf Si o> 00 CM 0.66 0.58 0.40 0.30 0.16 0.10 to 1.30 0.80 0.44 0.32 0.30 0.36 0.38 0.38 0.32 0.32 0.24 0.32 0.34 0.40 0.34 0.20 0.22 0.24 0.24 0.26 0.18 0.18 0.10 0.00 Tf 6.30 7.60 2.36 Tf (V Tf <£. Tf to CO o LO o Tf $ s 00 CO 2.18 2.10 2.10 1.40 1.24 1.20 1.00 0.74 0.45 0.19 CO 0.86 0.40 0.24 0.16 0.24 0.26 0.34 0.38 0.38 0.52 0.52 0.58 0.60 0.66 0.72 0.82 0.82 0.80 0.78 0.80 0.74 0.76 0.60 0.50 CM 1.12 0.40 0.32 0.28 0.38 0.39 0.50 0.50 0.52 0.42 0.50 0.34 0.26 0.24 0.30 0.12 0.12 0.08 0.04 0.06 0.04 0.08 0.02 0.00 1.28 0:80 0.56 0.44 0.48 0.44 0.54 0.60 0.68 0.70 0.70 0.78 0.94 0.92 1.06 0.94 0.96 0.80 0.72 0.68 0.62 0.58 0.47 0.36 Leachate Zinc (mg/L) Time (day) o Tf to LO o I' Tf co oo cn CM to CM o Tf Tf 10 00 to Si co to CO o CM co CM LO Tf CM to to CM Tf CO CM co o co oo Si CO r-10 to oo N. CO to T? Leachate Zinc (mg/L) {Column # Date 10/6/93 10/20/93 11/17/93 12/1/93 ll 2/15/93 12/29/93 1/12/94 1/26/94 2/9/94 2/23/94 3/9/94 I 3/23/94 I 4/6/94 4/20/94 5/4/94 I 5/25/94 6/8/94 6/29/94 7/27/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 Appendix F. Leachate Characteristics Data F.13 Iron 283 co 126.8 94.8 55.2 48.61 44.2 45.6 43.2J 47.0| 44.6 41.0 33.6 29.0 28.8 22.4 30.6 32.2 29.4 37.2 36.2 36.6 30.8 44.6 49.2 rv 52.1 100.4 63.6 45.6 45.2 35.0 34.6 36.8 42.2 45.6 45.4 45.6 70.2 79.4 99.4 108.8 123.2 139.4 165.0 168.6 178.4 177.0 156.1 CO 198.9 182.4 112.0 103.0 96.6 90.4 86.2 81.8 69.4 79.4 77.2 66.6 75.0 74.6 93.8 87.2 85.8 78.6 65.4 97.0 74.0 83.4 36.5 m T— 89.4 102.0 62.4 56.2 47.6 43.0 37.8 46.8 56.2 58.8 60.0 57.0 74.4 105.8 138.8 172.8 202.0 220.8 268.6 277.6 276.2 281.8 273.0 Tt 127.9 127.6 63.6 53.4 47.2 47.8 44.2 48.2 46.8 53.0 52.2 39.0 33.4 31.2 33.4 24.4 25.0 24.4 22.2 24.0 24.4 24.6 26.3 co 153.9 181.6 108.8 98.0 95.2 93.4 97.8 104.4 111.4 124.2 122.8 116.2 109.2 121.6 125.4 120.4 119.6 109.6 111.4 115.8 101.0 101.6 82.1 CM 164.7 190.0 j 99.2 94.0 105.0 110.4 119.0 118.8 142.6 154.0 155.0 113.8 87.4 83.2 85.6 68.6 73.4 71.8 84.4 77.0 65.4 72.0 60.5 144.8 154.8 98.0 82.4 76.2 77.2 75.8 88.6 90.2 105.2 107.8 94.8 72.0 62.8 66.2 51.4 64.4 61.0 75.0 87.4 62.6 64.8 53.0 o 99.4 127.2 71.6 58.4 60.0 62.8 64.8 72.8 80.2 85.6 83.0 77.8 67.6 77.8 75.6 68.4 73.6 65.2 62.4 64.6 57.2 52.4 47.7 O) 144.1 175.6 98.0 75.4 68.0 67.8 69.0 70.0 70.6 74.4 70.8 67.2 87.6 113.0 138.8 135.2 131.0 120.6 126.4 116.0 94.8 74.4 67.6 CO 118.9 123.2 67.6 57.8 55.4 56.6 90S 60.0 66.0 70.4 69.4 69.4 80.8 94.0 105.4 109.4 121.0 128.4 133.0 128.6 104.0 74.2 70.8 rv 144.9 132.8 [ 89.2 75.0 71.2 78.0 93.2 89.6 100.0 108.2 103.8 84.4 89.8 94.6 200.0 93.8 86.0 77.8 66.4 48.8 71.6 87.2 87.1 co 76.5 122.4 87.2 74.4 70.8 70.6 66.6 76.6 80.0 88.4 90.0 100.6 119.8 171.0 90.4 220.8 220.2 224.4 215.4 203.8 195.2 159.2 123.8 in 109.9 105.6 76.8 68.2 66.4 65.6 65.2 70.2 68.6 75.4 80.0 88.0 109.4 135.6 142.4 145.2 148.6 155.4 167.6 154.8 154.0 113.0 115.2 t 121.3 168.8 93.2 87.6 87.4 81.2 82.2 86.0 91.8 97.0 96.6 97.4 100.6 135.4 157.6 157.0 164.8 140.6 144.6 145.6 136.4 125.4 94.9 co 89.5 98.8 72.8 71.8 73.2 78.8 86.2 95.0 100.0 118.0 114.6 130.0 124.2 161.4 173.8 194.0 212.0 204.6 210.6 199.2 193.6 177.0 147.2 CM 112.4 82.0 75.2 59.6 65.0 65.0 76.8 77.0 78.8 72.2 92.4 84.4 78.8 78.8 82.2 72.8 70.0 64.2 64.2 61.8 CO cd CO 77.4 80.9 56.8 63.2 56.0 49.8 51.2 49.4 53.6 51.6 54.4 56.8 55.4 59.6 65.6 77.6 92.4 96.8 99.6 112.0 102.0 101.6 93.6 85.6 77.2 Leachate Iron (mg/L) Time (day) o co m o rv Tt oo oo o> CM CO CM o Tt 3 8 co co 0) o CM co CM in Tt CM CO co CM a CM § co 83 co rv in co oo rv co Leachate Iron (mg/L) Column # Date 10/6/93 10/20/93 11/17/93 12/1/93 112/15/93 12/29/93 1/12/94 1/26/94 2/9/94 2/23/94 3/9/94 3/23/94 4/6/94 4/20/94 5/4/94 5/25/94 6/8/94 6/29/94 7/27/94 8/10/94 8/31/94 9/28/94 10/19/94 Appendix F. Leachate Characteristics Data F.14 Sodium 284 co 344.4 273.6 106.8 62.0 57.4 46.0 31.4 27.81 24.4 21.0 13.4 14.6 11.4 10.8 co rv CM co CM tri Tf Tf CM CO o cd co cvi CM cvi CM cvi co d rv 301.2 268.8 111.2 78.0 43.6 28.6 19.6 16.2 13.4 10.4 CM Tf o rv co rv CM cb Tf od oo ob Tf cri 10.2 10.2 10.4 co cri o ai o od tv co CO 273.0 214.4 90.8 64.0 40.6 28.4 16.4 12.6 11.0 ID ai Tf cd oo tri CM tri OS o Tf 00 cd o co' Tf cvi o cvi o cvi cp Tf CO Tf d U) 458.8 421.6 144.4 60.0 65.0 46.2 32.4 26.8 22.8 17.0 co cri cp *— cp o Tf o Tf CM Tf co Tf o Tf oo cvi oo cvi Tf Tf d at co co cb Tt 386.8 393.2 155.6 98.0 63.2 47.2 33.8 25.4 18.6 15.0 Tf rv co co CO co' o co' CM CM oo CM CM q q q q CM co 417.4 361.2 116.0 92.0 51.2 36.0 24.4 18.8 14.6 11.0 Tf Tf o co Tf Tf CO CO CO CM CM CM CM cvi CM cvi CM cvi 00 cvi CD cvi CM cvi o cvi Tf CM 268.6 488.0 121.2 76.0 43.0 30.6 19.8 13.6 Tf cri CM rv co cd CM CO o c\i Tf °s oo d co d oo d oo d co d co d co d oo d 479.4 370.8 133.6 64.0 57.2 42.0 29.2 21.4 17.6 13.8 co rv oo rv Tf Tf Tf cd co CM GO co Tf in cp CD rv d O 309.8 274.0 88.4 54.0 43.4 34.0 26.0 20.0 15.6 11.6 OS CO CO Tf Tf CM Tf Tf CO co cvi co CM CM cvi o cvi o cvi oq CD CD CM 0> 371.8 338.4 103.6 58.0 41.8 30.0 17.0 12.2 10.2 oo rv CM cvi o tri Tf tri co tri co tri 0'9 CO Tf o Tf o Tf Tf Tf 00 CO CO CO in CO o CO co 493.8 274.0 98.4 64.0 49.0 39.8 28.6 23.4 22.8 17.0 o cri 10.8 10.0 10.0 oo oo' Tf rv CM CO CM tri CM Tf CM Tf Tf CO CO cvi CO cvi CD rv 443.2 351.6 134.4 76.0 50.4 35.8 27.4 18.4 15.2 oo cri Tf cd o tri Tf Tf oo co co co 00 CM o CM cq Tf cp CM CM CM oo d CO 422.2 353.61 158.0 90.0 58.2 40.0 28.2 19.6 14.6 10.8 CO tri Tf CD CM CO co co o cd Tf co CM CO CM CO GO iri CM CO O co o co Tf ui CO tri ID 500.6 378.8 132.8 84.0 61.4 47.8 39.4 29.0 Tf cri Tf ID CM d O Tf oo cd CM tri o Tf CO cd Tf cvi q CO cri 00 co CO co 00 tri CO Tf CM Tf Tf 471.6 402.8 148.4 78.0 51.6 33.2 19.2 16.2 12.8 Tf cri co cd oo co 00 tri oo tri 00 tri OS o Tf o cd co cvi Tf cvi CM cvi o cvi o cvi CM CO 406.0 342.4 129.6 76.0 54.8 39.4 25.0 17.8 15.4 10.8 CM Tf Tf rv CO co Tf co co tri Tf tri CM tri o tri Tf Tf Tf Tf o Tf co cd CM cd o cd CM 473.6 338.4 147.2 92.0 70.6 54.2 44.0 35.6 30.2 22.2 19.8 19.0 16.0 13.0 co ai o rv Tf co CM tri OS oo Tf CM Tf CM cd CD cvi o cvi Leachate Sodium (mg/L) 282.2 259.2 115.2 68.0 47.2 33.8 23.6 15.8 12.4 Tf od Tf CM Tf tri 00 Tf Tf Tf 00 cd CM cd CM cd co c\i Tf cvi co cvi CM cvi o cvi 01 in Leachate Sodium (mg/L) Time (day) o Tf CM Tf CD in o rv Tf GO CO O) CM co CM o Tf Tf tn co co CM 00 CO 01 o CM CO CM in Tf CM co co CM Tf O) CM oo o co 01 CM co tv 10 co 00 rv co co o Tf Leachate Sodium (mg/L) Column # Date 10/6/93 10/20/93 11/17/93 I 12/1/93 12/15/93 12/29/93 1/12/93 1/26/94 2/9/94 2/23/94 3/9/94 3/23/94 4/6/94 4/20/94 5/4/94 5/25/94 6/8/94 6/29/94 7/27/94 8/10/94 8/31/94 9/28/94 10/19/94 11/16/94 Appendix F. Leachate Characteristics Data F.15 Chlorides 285 co o o LO o co CM o cn o LO o o to |v O rf rf o CO CM o co o 1— IV LO o rf CD O 3 o r- o rr o o co o IV IO LO £ o o LO CM o 8 8 rr O CM CO o o co o s 8 CO LO LO LO o CM o CO 8 CO co r? CM o CO iv o co CM o CO o o 1— LO IV CM LO r» LO o to CM o •<t CM o to oo 00 rr o o co rr o LO o o o 3 LO rr O) o rr o to cn O) rr cn o LO o co co o CM rr o co o rf o CM 00 |v co LO |v o co LO o CM o to o T CM co rt CM CO o O) rr s CM o oo 8 r-LO 3 LO o 0) CO o co CM o 00 o rr co LO rr o CM co o LO CM I oo cn $ cn CM co o o to o o CM o rr o o r-rr CM co CM o o CO CM o CD y— §_ 0> Iv rr LO 1 Leachate Chlorides (mg/L) o co rf o cn o CM 1— s oo CO CM 1 Leachate Chlorides (mg/L) Time (day) rr CM rr CO LO o r- 3 CM 1 Leachate Chlorides (mg/L) Column # Date 20/10/93 17/11/93 1/12/93 15/12/93 29/12/93 26/1/94 Appendix G Gas Characteristics Data G.l Composition of Gas Gas Composition (% by volume) ! I I I I I I I I Date Time(day) Column #1 Column #2 Column #3 Column #4 Gas CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 10/4/93 0 71.0 0.0 5.0 24.0 67.0 0.3 9.3 23.7 67.0 0.3 10.0 22.7 64.0 1.6 16.0 19.4 10/18/93 14 65.7 0.5 4.8 29.0 61.5 0.5 8.5 29.5 61.5 0.5 9.0 29.0 64.0 1.0 11.0 24.0 11/1/93 28 62.3 0.6 10.1 27.0 58.7 0.5 13.1 27.7 52.2 1.6 10.7 35.4 63.3 0.3 8.6 27.7 11/15/93 42 58.6 0.6 8.6 32.1 49.0 1.4 13.0 36.6 53.6 0.5 6.3 39.6 37.3 5.2 23.6 33.8 11/29/93 56 58.5 0.4 6.1 34.9 52.3 0.9 9.0 37.6 54.6 0.3 4.8 40.0 55.2 0.8 8.7 35.2 12/13/93 70 58.0 0.0 4.7 36.0 54.8 0.4 6.2 38.6 55.6 0.3 3.9 40.1 54.3 0.6 7.3 37.7 12/27/93 84 51.7 1.1 6.5 40.6 45.0 1.7 8.3 44.9 50.6 0.8 4.7 43.8 36.8 4.4 18.1 40.5 1/10/94 98 56.0 0.3 3.9 39.8 54.6 0.3 3.6 41.4 54.4 0.0 2.7 42.6 35.9 4.4 15.9 43.7 2/8/94 127 47.5 1.6 7.6 43.1 47.0 1.4 5.8 45.7 48.5 1.6 5.6 44.3 44.5 1.5 7.3 46.5 2/21/94 140 46.3 1.6 6.9 45.1 45.5 1.0 5.2 48.3 47.0 1.4 5.0 46.6 30.6 3.7 12.9 52.7 3/18/94 165 50.3 0.0 3.4 46.2 49.2 0.6 2.4 47.8 50.7 0.6 2.3 46.4 45.8 0.7 3.1 50.4 3/21/94 168 48.3 0.7 3.4 47.5 48.6 0.6 2.6 48.1 51.0 0.6 2.5 45.8 46.4 0.5 2.6 50.4 4/4/94 182 51.3 0.4 2.4 45.8 48.5 0.5 2.4 48.6 50.4 0.6 2.3 46.6 47.8 0.6 2.1 49.5 4/18/94 196 53.2 0.0 2.0 44.6 47.6 0.5 2.3 49.6 51.5 0.5 2.3 45.6 47.5 0.6 2.5 49.3 5/2/94 210 52.5 0.5 1.3 45.5 50.7 0.0 1.9 47.4 49.8 0.5 2.2 47.3 47.0 0.5 2.1 50.4 5/23/94 231 49.4 0.6 22 47.8 46.2 0.5 1.9 51.4 49.7 0.4 1.7 48.2 45.7 0.4 1.8 52.0 6/6/94 245 55.0 0.0 2.2 42.8 56.4 0.0 2.0 41.5 53.4 0.0 1.4 45.1 52.8 0.0 1.2 45.9 6/27/94 266 49.5 0.4 1.9 48.0 43.9 0.4 1.8 53.8 60.8 0.0 0.0 39.1 57.0 0.0 0.0 43.0 7/25/94 294 50.9 0.3 1.1 47.6 33.4 0.0 0.0 66.6 56.6 0.0 0.5 42.9 55.6 0.0 0.0 44.4 8/8/94 308 50.3 0.0 0.0 49.6 49.4 0.0 0.0 50.6 48.1 0.0 0.0 51.8 46.0 0.0 0.0 54.0 8/29/94 329 51.4 0.0 0.0 48.5 44.8 0.0 0.0 55.1 49.3 0.0 0.0 50.7 45.6 0.3 0.0 54.0 9/26/94 357 44.3 0.0 0.0 55.7 45.7 0.0 0.0 54.3 45.4 0.0 0.0 54.6 39.3 0.3 0.0 60.3 10/17/94 378 48.6 0.0 0.0 51.4 46.3 0.0 0.0 53.7 51.3 0.0 0.0 48.7 45.4 0.0 0.0 54.5 11/4/94 396 41.1 0.4 1.3 57.1 39.5 02 0.8 59.4 40.3 0.4 1.5 57.7 38.0 0.3 1.3 60.3 11/14/94 406 48.4 0.0 0.0 51.6 45.1 0.0 0.0 54.9 48.0 0.3 0.0 51.7 44.3 0.3 0.0 55.4 12/23/94 445 48.3 0.4 0.0 51.3 44.9 0.3 0.0 54.7 47.1 0.4 0.0 52.4 45.0 0.4 0.0 54.6 1/9/95 462 46.6 0.4 0.0 53.0 44.9 0.3 0.0 54.7 47.0 0.3 0.0 52.6 44.4 0.4 0.0 55.2 1/16/95 469 48.0 0.4 0.0 51.6 41.9 0.0 0.0 58.0 45.7 0.3 0.0 54.0 43.8 0.4 0.0 55.8 1/23/95 476 41.6 0.3 0.0 58.1 40.0 0.5 0.0 59.5 39.9 0.3 0.0 59.7 37.2 0.3 0.0 62.4 1/30/95 483 39.7 0.4 0.0 59.9 38.6 0.4 0.0 61.0 38.1 0.3 0.0 61.6 35.0 0.5 1.5 63.0 2/13/95 497 39.0 0.5 4.7 55.8 38.1 0.3 2.8 58.8 36.3 0.3 0.0 63.4 31.3 0.2 0.0 68.4 2/27/95 511 40.4 0.4 8.4 50.7 38.8 0.3 8.0 52.9 37.2 0.2 8.4 54.1 29.3 1.2 11.2 58.2 3/13/95 525 38.7 0.4 0.0 60.9 37.9 0.0 0.0 62.0 36.2 0.1 0.0 63.7 29.4 0.0 0.0 70.6 3/27/95 539 36.1 0.4 0.0 63.4 34.2 0.4 0.0 65.3 33.5 0.4 0.0 66.1 28.1 0.7 3.0 68.2 4/3/95 546 36.8 0.0 0.0 63.2 36.7 0.0 0.0 63.3 35.8 0.0 0.0 64.2 31.3 0.0 0.0 68.7 4/10/95 553 44.6 0.0 0.0 55.4 41.8 0.0 0.0 58.2 41.6 0.0 0.0 58.4 35.3 0.0 0.0 64.7 4/17/95 560 45.8 0.0 0.0 54.2 43.3 0.0 0.0 56.7 43.4 0.0 0.0 56.5 39.8 0.0 0.0 60.2 4/24/95 567 46.1 0.0 0.0 53.9 43.7 0.0 0.0 56.3 43.5 0.0 0.0 56.5 41.3 0.0 0.0 58.7 5/8/95 581 45.9 0.0 0.0 54.1 44.1 0.0 0.0 55.9 45.4 0.0 0.0 54.6 44.3 0.0 0.0 55.7 5/26/95 599 46.0 0.0 0.0 54.0 43.7 0.0 0.0 56.3 46.9 0.0 0.0 53.1 43.5 0.0 0.0 56.5 6/26/95 630 46.4 0.0 0.0 53.6 44.2 0.0 0.0 55.8 44.8 0.0 0.0 55.2 45.2 0.0 0.0 54.8 286 Appendix G. Gas Characteristics Data 287 Gas Composition (% by volume) Column #5 Column #6 Column #7 Column #8 Date Time(day) CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 10/4/93 0 66.0 1.0 13.0 20.0 49.3 4.3 23.4 23.0 61.5 1.1 8.0 29.5 59.1 1.6 9.4 29.9 10/18/93 14 65.0 0.5 10.2 24.3 59.2 0.5 10.3 30.0 59.0 0.4 5.5 35.1 58.6 0.4 5.0 36.0 11/1/93 28 63.5 0.4 10.3 25.8 54.7 0.7 15.2 29.3 56.9 0.4 4.2 38.5 58.3 0.2 3.5 37.8 11/15/93 42 59.7 0.6 8.1 31.5 43.5 2.0 16.8 37.7 51.0 0.5 4.1 44.3 45.5 1.5 6.1 46.9 11/29/93 56 61.2 0.0 5.6 33.1 52.6 0.6 8.5 38.2 56.3 0.0 1.6 42.1 53.3 0.0 2.5 44.1 12/13/93 70 58.9 0.4 4.0 36.6 46.8 0.3 8.0 44.8 50.5 0.3 2.7 46.4 52.1 0.3 2.5 45.1 12/27/93 84 54.4 0.6 4.0 40.9 35.6 2.2 11.1 51.2 48.0 0.5 2.7 48.7 50.4 0.4 2.5 46.6 1/10/94 98 51.1 1.7 7.4 39.7 42.0 1.5 8.4 48.0 45.3 2.4 9.5 42.7 51.6 0.2 1.9 46.2 2/8/94 127 46.1 1.4 5.5 46.9 40.8 1.1 5.5 52.5 46.1 1.1 4.8 47.8 47.5 1.3 4.8 46.3 2/21/94 140 43.4 1.2 4.5 50.8 40.6 1.3 5.4 52.7 43.1 1.4 5.7 49.7 44.5 1.4 5.7 48.2 3/18/94 165 48.4 0.9 3.4 47.3 45.2 0.7 2.4 51.6 48.1 0.6 2.3 49.0 50.0 0.5 2.4 47.0 3/21/94 168 50.1 0.5 2.0 47.2 47.4 0.6 1.9 50.1 49.5 0.5 1.9 48.0 52.7 0.0 1.9 45.4 4/4/94 182 50.2 0.5 1.7 47.5 49.0 0.5 0.8 49.6 47.1 0.5 2.1 50.3 52.5 0.5 1.4 45.6 4/18/94 196 50.2 0.5 2.0 47.1 48.4 0.2 0.9 50.3 46.9 0.5 2.1 50.4 51.9 0.6 1.7 45.7 5/2/94 210 49.8 0.7 2.1 47.3 52.6 0.4 1.1 45.8 48.2 0.5 1.8 49.4 52.8 5.2 1.3 40.7 5/23/94 231 48.9 0.5 1.7 48.9 47.3 0.4 1.6 50.7 46.0 0.4 1.5 51.9 49.9 0.5 1.7 47.8 6/6/94 245 49.2 0.4 3.7 49.3 47.2 0.4 1.3 50.9 45.1 0.5 1.5 52.9 48.9 0.4 1.5 49.2 6/27/94 266 47.8 0.0 1.4 50.8 50.7 0.0 1.1 48.2 44.8 0.0 0.9 54.3 48.2 0.3 1.6 49.8 7/25/94 294 50.1 0.2 1.0 48.6 57.5 0.0 0.0 42.5 49.8 0.0 0.0 50.2 60.3 0.0 0.0 39.7 8/8/94 308 51.5 0.0 0.0 48.5 48.9 0.0 0.0 51.1 44.0 0.0 0.0 56.0 47.9 0.0 0.0 52.1 8/29/94 329 49.1 0.0 0.0 50.8 45.3 0.0 0.0 54.7 40.0 0.0 1.0 59.0 48.3 0.0 0.0 51.7 9/26/94 357 44.7 0.4 0.0 54.9 46.0 0.0 0.0 54.0 45.9 0.0 0.0 54.1 46.6 0.0 0.0 53.4 10/17/94 378 48.1 0.0 0.0 51.9 46.9 0.0 0.0 53.1 43.6 0.0 0.0 56.4 58.4 0.0 0.0 41.6 10/28/94 389 10/31/94 392 11/4/94 396 41.4 0.3 1.5 56.7 40.9 0.3 1.3 57.5 35.9 0.5 1.7 61.8 40.4 0.3 1.4 57.9 11/10/94 402 11/14/94 406 51.1 0.0 0.0 48.8 47.6 0.3 0.0 52.1 42.3 0.4 0.0 57.3 47.5 0.0 0.0 52.5 11/21/94 413 12/23/94 445 49.5 0.0 0.0 50.5 47.5 0.3 0.0 52.1 42.7 0.6 0.0 56.7 46.4 0.3 0.0 53.3 1/9/95 462 50.1 0.0 0.0 49.8 44.9 0.3 0.0 54.7 40.0 0.4 0.0 59.5 47.1 0.0 0.0 52.9 1/16/95 469 47.3 0.3 0.0 52.4 45.8 0.4 0.0 53.8 45.2 0.4 0.0 54.4 47.3 0.0 0.0 52.7 1/23/95 476 41.3 0.3 0.0 58.3 38.8 0.3 0.0 60.8 40.4 0.5 0.0 59.0 40.2 0.4 0.0 59.4 1/30/95 483 39.2 0.3 0.0 60.5 35.9 0.4 0.0 63.7 39.4 0.5 0.0 60.1 38.7 0.3 0.0 61.0 2/13/95 497 36.8 0.4 0.0 62.8 34.5 0.3 0.0 65.2 38.8 0.4 0.0 60.8 37.7 0.3 0.0 62.1 2/27/95 511 36.5 0.2 0.0 63.3 35.3 0.5 8.8 55.7 38.0 0.4 6.5 55.1 3/13/95 525 34.3 0.0 0.0 65.7 34.3 0.0 0.0 65.7 37.7 0.0 0.0 62.3 36.7 0.0 0.0 63.3 3/27/95 539 32.3 0.4 0.0 67.2 31.0 0.4 0.0 68.5 35.5 0.4 1.5 62.4 34.6 0.4 0.0 65.0 4/3/95 546 36.6 0.0 0.0 63.4 33.8 0.0 0.0 66.2 39.1 0.0 0.0 60.9 39.0 0.0 0.0 61.0 4/10/95 553 40.8 0.0 0.0 59.2 41.2 0.0 0.0 58.8 41.1 0.0 0.0 58.8 42.6 0.0 0.0 57.4 4/17/95 560 42.8 0.0 0.0 57.2 42.6 0.0 0.0 57.4 42.2 0.0 0.0 57.8 43.7 0.0 0.0 56.3 4/24/95 567 43.7 0.0 0.0 56.2 43.3 0.0 0.0 56.6 42.7 0.0 0.0 57.3 44.0 0.0 0.0 55.9 5/8/95 581 44.5 0.0 0.0 55.5 43.2 0.0 0.0 56.8 42.1 0.0 0.0 57.9 43.8 0.0 0.0 56.2 5/26/95 599 44.7 0.0 0.0 55.3 43.5 0.0 0.0 56.4 43.2 0.5 0.0 56.3 44.3 0.0 0.0 55.7 6/26/95 630 45.1 0.0 0.0 54.9 44.61 0.0 0.0 55.6 44.2 0.0 0.0 55.8 44.7 0.0 0.0 55.3 Appendix G. Gas Characteristics Data 288 Gas Composition (% by volume) Column #9 Column #10 Column #11 Column #12 Date Time(day) CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 10/4/93 0 63.9 0.8 11.6 23.6 57.0 3.8 31.5 7.4 80.0 0.5 11.0 8.5 64.0 2.0 22.0 12.0 10/18/93 14 60.0 0.6 8.2 31.2 45.1 4.6 42.2 8.1 75.5 0.6 9.5 14.4 56.0 3.0 23.0 18.0 11/1/93 28 57.7 0.3 5.7 36.2 30.5 15.6 36.2 17.7 71.0 0.6 12.7 15.7 67.6 0.5 13.0 18.8 11/15/93 42 51.5 0.6 5.3 42.6 52.6 2.4 30.7 14.3 67.9 0.5 10.4 21.1 56.5 1.7 15.9 25.9 11/29/93 56 57.4 0.0 2.5 40.1 60.7 1.5 23.4 14.4 69.6 0.0 6.9 23.5 68.5 0.5 8.3 22.6 12/13/93 70 51.4 0.3 2.8 45.5 63.6 0.5 18.5 17.5 67.5 0.4 5.5 26.5 61.0 0.5 9.0 29.4 12/27/93 84 49.0 0.5 2.6 47.8 45.0 4.0 29.0 21.8 63.8 0.0 4.8 31.2 50.3 2.4 13.7 33.5 1/10/94 98 49.6 0.3 2.3 47.8 64.6 0.5 13.4 21.4 64.4 0.2 3.8 31.5 58.8 0.3 7.3 33.6 2/8/94 127 45.0 1.2 4.9 48.7 62.4 1.5 10.4 25.6 57.8 1.4 5.4 35.3 40.7 3.7 15.8 39.7 2/21/94 140 42.7 1.2 4.8 51.1 38.9 5.2 20.9 34.9 53.3 1.2 5.6 39.8 33.5 5.6 17.9 43.0 3/18/94 165 47.6 0.6 2.4 49.3 62.2 0.5 3.6 33.7 57.8 0.8 3.2 38.2 51.4 0.8 4.8 42.9 3/21/94 168 48.3 0.6 2.2 48.8 40.9 18.4 8.3 32.3 57.5 0.7 2.8 38.9 39.9 3.3 10.7 46.1 4/4/94 182 51.1 0.5 1.4 47.0 59.5 0.8 3.4 36.2 51.1 0.6 2.8 45.5 44.5 0.7 4.6 50.1 4/18/94 196 49.6 0.5 2.1 47.8 59.4 0.5 2.9 37.2 47.0 0.5 3.0 49.3 41.6 0.5 4.4 53.4 5/2/94 210 51.1 0.2 1.5 47.1 56.7 0.6 3.3 39.4 48.3 0.5 2.5 48.6 37.5 0.9 4.9 56.7 5/23/94 231 48.4 0.4 1.5 49.5 51.8 0.6 2.7 44.9 40.5 0.4 2.4 56.6 32.9 0.6 3.5 62.8 6/6/94 245 48.1 0.5 1.5 49.8 51.6 0.4 2.1 45.9 42.1 0.4 10.1 47.3 34.1 0.5 3.8 61.5 6/27/94 266 46.6 0.4 2.2 50.8 48.9 0.4 2.1 48.5 55.9 0.0 0.0 44.1 33.9 0.4 3.7 62.0 7/25/94 294 49.7 0.2 0.0 50.1 50.4 0.3 1.2 48.1 46.0 0.4 15.0 38.0 39.4 0.2 0.9 59.5 8/8/94 308 50.2 0.0 0.0 49.8 39.8 1.6 3.7 54.9 43.2 0.0 3.8 52.9 40.1 0.5 0.0 59.4 8/29/94 329 48.1 0.4 0.0 51.5 44.1 0.0 0.0 55.9 42.0 0.0 0.0 58.0 37.0 0.0 1.0 61.9 9/26/94 357 43.7 0.0 0.0 56.3 44.7 0.0 0.0 55.3 38.8 0.0 1.4 59.7 40.7 0.0 1.7 57.6 10/17/94 378 49.3 0.0 0.0 50.7 74.8 0.0 0.0 25.1 36.9 0.0 0.0 63.1 50.3 0.0 0.9 48.8 10/28/94 389 10/31/94 392 11/4/94 396 38.1 0.3 1.2 60.3 36.4 0.4 1.7 61.4 33.4 0.8 1.4 64.3 31.1 0.3 2.1 66.4 11/10/94 402 11/14/94 406 48.7 0.3 0.0 51.0 42.2 0.0 0.0 57.8 36.8 0.3 0.0 62.9 36.3 0.3 1.0 62.4 11/21/94 413 12/23/94 445 44.5 0.4 0.0 55.1 41.1 0.4 0.0 58.5 32.8 0.5 10.3 56.3 32.2 0.4 0.0 67.3 1/9/95 462 44.5 0.5 0.0 54.9 38.9 0.4 0.0 60.6 34.8 0.4 1.5 63.3 34.2 0.0 0.0 65.8 1/16/95 469 44.8 0.0 0.0 55.1 42.6 0.4 0.0 56.9 41.1 0.0 0.0 58.8 36.7 0.4 0.0 62.8 1/23/95 476 36.6 0.4 0.0 63.0 39.6 0.5 0.0 59.8 36.6 0.3 0.0 63.0 33.6 0.4 0.0 66.0 1/30/95 483 33.0 0.4 0.0 66.5 39.2 0.4 0.0 60.3 34.4 0.4 0.0 65.2 31.9 0.4 0.0 67.7 2/13/95 497 29.8 0.4 0.0 69.7 37.7 0.4 0.0 61.8 33.6 0.3 4.0 62.0 28.9 0.3 0.0 70.7 2/27/95 511 27.5 0.3 8.9 63.3 33.8 0.4 8.8 57.0 28.1 0.4 8.5 62.9 3/13/95 525 24.6 0.0 4.1 71.2 41.6 0.0 0.0 58.4 34.4 0.0 0.0 65.6 24.2 0.0 5.7 70.1 3/27/95 539 25.7 0.4 2.6 71.2 35.7 0.4 0.0 63.8 29.4 0.4 0.0 70.2 24.9 0.4 3.5 71.1 4/3/95 546 28.8 0.0 0.0 71.1 39.0 0.0 0.0 60.9 31.4 0.0 0.0 68.6 28.2 0.0 0.0 71.7 4/10/95 553 33.7 0.0 0.0 66.3 41.1 0.0 0.0 58.8 35.2 0.0 0.0 64.8 32.4 0.0 0.0 67.6 4/17/95 560 38.6 0.0 0.0 61.4 42.8 0.0 0.0 57.2 39.2 0.0 0.0 60.8 38.1 0.0 0.0 61.9 4/24/95 567 40.5 0.0 0.0 59.5 42.7 0.0 0.0 57.2 40.3 0.0 0.0 59.6 40.7 0.0 0.0 59.3 5/8/95 581 41.5 0.0 0.0 58.4 43.0 0.0 0.0 57.0 41.1 0.0 0.0 58.8 42.3 0.0 0.0 57.7 5/26/95 599 42.8 0.0 0.0 57.2 42.9 0.0 0.0 57.1 41.4 0.0 0.0 58.6 43.9 0.0 0.0 56.1 6/26/95 630 44.2 0.0 0.0 55.8 43.9 0.0 0.0 56.1 42.3 0.0 0.0 57.7 45.2 0.0 0.0 54.8 Appendix G. Gas Characteristics Data 289 Gas Composition (% by volume) Column #13 Column #14 Column #15 Date Time(day) CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 10/4/93 0 73.0 0.8 18.2 7.0 75.0 0.0 4.5 19.5 76.5 0.6 8.5 14.4 10/18/93 14 60.0 2.5 26.3 11.2 70.0 0.3 4.0 25.7 68.0 1.0 8.0 23.0 11/1/93 28 61.0 2.2 24.5 12.1 71.8 0.3 2.7 25.2 69.2 0.3 7.1 23.4 11/15/93 42 64.6 1.0 18.5 15.9 64.0 0.5 3.2 32.3 57.7 0.8 9.5 32.0 11/29/93 56 70.5 0.0 14.3 15.2 67.9 0.0 1.7 30.3 56.3 0.0 7.5 36.2 12/13/93 70 65.5 0.6 13.5 20.0 62.9 0.4 2.4 34.3 54.1 0.4 6.2 39.2 12/27/93 84 58.2 1.7 15.4 24.7 42.3 4.3 11.4 42.0 45.5 1.1 8.0 45.3 1/10/94 98 65.5 0.4 9.5 24.6 46.1 5.6 21.9 26.3 49.3 0.3 4.8 45.4 2/8/94 127 62.7 1.3 8.3 27.6 45.8 3.0 9.9 41.1 45.6 1.3 5.0 47.9 2/21/94 140 605 1.4 7.2 31.1 51.3 1.5 6.6 40.5 42.1 0.9 5.9 51.0 3/18/94 165 62.9 0.8 4.1 32.1 55.0 0.5 2.5 41.9 47.3 0.7 3.0 48.9 3/21/94 168 60.0 1.2 4.9 33.7 39.7 3.6 8.4 48.1 47.3 0.8 3.0 48.8 4/4/94 182 59.0 0.8 4.1 35.9 45.9 0.7 3.0 50.3 53.6 0.5 1.7 44.2 4/18/94 196 58.5 0.6 3.3 37.6 43.3 0.6 3.0 52.9 51.4 0.4 2.1 46.0 5/2/94 210 58.3 0.6 3.1 37.9 34.8 2.1 6.0 57.0 51.4 0.5 2.0 46.0 5/23/94 231 51.1 0.9 3.0 44.9 39.1 0.5 2.3 58.0 51.5 0.4 1.5 46.5 6/6/94 245 49.7 0.7 2.8 46.7 40.9 0.5 2.2 56.3 49.5 0.3 1.4 48.8 6/27/94 266 51.8 0.0 0.0 48.2 50.0 0.0 0.0 50.0 49.5 0.7 1.3 48.5 7/25/94 294 51.2 0.0 0.0 48.7 43.5 0.3 0.0 56.2 54.4 0.0 0.7 44.8 8/8/94 308 41.4 0.8 2.3 55.6 39.6 0.3 0.0 60.0 50.1 0.3 0.0 49.5 8/29/94 329 42.8 0.0 1.2 56.0 39.4 0.0 0.0 60.6 46.5 0.0 0.0 53.4 9/26/94 357 42.6 0.0 0.0 57.3 38.3 0.0 0.0 61.7 51.0 0.0 0.0 49.0 10/17/94 378 44.9 0.0 0.0 55.1 49.8 0.0 0.0 50.2 52.1 0.3 0.0 47.6 10/28/94 389 10/31/94 392 11/4/94 396 34.9 0.4 1.9 62.7 36.0 0.0 1.1 62.8 44.0 0.3 1.1 54.4 11/10/94 402 11/14/94 406 41.9 0.3 0.0 57.7 38.8 0.4 0.0 60.8 50.2 0.0 0.0 49.8 11/21/94 413 12/23/94 445 43.9 0.4 0.0 55.7 33.8 0.5 0.0 65.6 48.9 0.4 0.0 50.7 1/9/95 462 40.9 0.3 0.0 58.7 33.5 0.4 1.6 64.5 49.5 0.2 0.0 50.2 1/16/95 469 43.8 0.4 0.0 55.7 39.3 0.0 0.0 60.7 51.3 0.0 0.0 48.6 1/23/95 476 37.6 0.4 0.0 61.9 34.3 0.3 0.0 65.3 46.9 0.3 0.0 52.7 1/30/95 483 34.3 0.3 0.0 65.4 32.5 0.6 0.0 66.9 46.8 0.3 0.0 52.0 2/13/95 497 30.2 0.5 0.0 69.3 30.3 0.5 0.0 69.2 45.4 0.4 0.0 54.1 2/27/95 511 27.9 0.2 0.0 71.8 29.1 0.8 9.2 60.8 3/13/95 525 28.6 0.0 0.0 71.3 27.0 0.0 3.7 69.2 46.9 0.0 0.0 53.1 3/27/95 539 25.8 0.5 2.3 71.3 27.5 0.5 0.0 72.0 43.3 0.4 0.0 56.3 4/3/95 546 28.4 0.0 0.0 71.6 31.0 0.0 0.0 69.0 45.6 0.0 0.0 54.4 4/10/95 553 34.0 0.0 0.0 65.9 35.7 0.0 0.0 64.3 45.9 0.0 0.0 54.0 4/17/95 560 39.5 0.0 0.0 60.5 39.9 0.0 0.0 60.1 45.8 0.0 0.0 54.2 4/24/95 567 41.6 0.0 0.0 58.4 41.3 0.0 0.0 58.7 45.8 0.0 0.0 54.2 5/8/95 581 43.1 0.0 0.0 56.8 41.8 0.0 0.0 58.2 45.1 0.0 0.0 54.9 5/26/95 599 43.6 0.0 0.0 56.4 42.5 0.0 0.0 57.5 45.4 0.0 0.0 54.6 6/26/95 630 44.1 0.0 0.0 55.8 44.1 0.0 0.0 55.9 45.6 0.0 0.0 54.4 Appendix G. Gas Characteristics Data 290 Gas Composition (% by volume) Column #16 Column #17 Column #18 Date Time(day) CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 CO-2 0-2 N-2 CH-4 10/4/93 0 57.2 0.3 0.8 41.7 76.0 1.0 15.0 8.0 54.0 0.6 32.4 13.0 10/18/93 14 49.4 0.4 2.0 48.2 65.5 2.3 18.6 13.6 53.0 0.5 22.5 24.0 11/1/93 28 53.1 0.3 3.3 43.2 69.3 0.5 18.8 11.4 55.3 0.7 18.3 25.6 11/15/93 42 47.5 0.0 0.0 52.5 61.6 1.0 20.3 17.1 48.9 0.6 13.7 36.8 11/29/93 56 45.1 0.0 1.8 53.1 60.2 0.6 17.7 21.4 47.5 0.5 9.5 42.5 12/13/93 70 44.9 0.0 1.6 53.5 51.6 2.0 20.9 25.3 47.7 0.4 6.9 44.9 12/27/93 84 36.7 1.7 4.4 57.2 49.2 1.5 19.1 30.1 46.4 0.5 5.4 47.6 1/10/94 98 43.7 0.0 1.2 55.1 55.2 0.4 13.8 30.5 49.4 0.3 3.0 47.3 2/8/94 127 35.5 2.0 7.4 55.0 46.7 2.2 14.4 36.6 44.6 1.4 6.0 48.0 2/21/94 140 38.0 1.2 4.8 55.9 49.6 1.0 9.0 40.3 42.6 1.0 4.7 51.7 3/18/94 165 44.7 0.6 2.0 52.7 54.9 0.8 5.1 39.1 46.1 0.5 1.8 51.5 3/21/94 168 42.9 1.0 3.1 53.0 51.6 1.0 6.5 40.7 45.0 0.6 2.4 52.0 4/4/94 182 43.5 0.4 2.1 54.0 59.5 0.7 3.4 36.3 44.0 0.5 1.9 53.5 4/18/94 196 43.5 0.0 2.6 53.3 59.9 0.5 2.8 36.7 43.4 0.5 2.0 54.1 5/2/94 210 42.5 0.6 2.2 54.6 63.3 0.4 1.9 34.3 43.1 0.3 1.9 54.5 5/23/94 231 43.8 0.4 1.5 54.2 59.3 0.5 1.5 38.7 41.7 0.4 1.7 56.1 6/6/94 245 42.8 0.4 1.4 55.4 57.2 0.5 1.5 40.8 41.4 0.5 2.8 55.2 6/27/94 266 43.7 0.0 0.8 55.3 77.9 0.5 0.7 20.9 44.3 0.0 1.2 54.3 7/25/94 294 46.8 0.0 0.0 53.2 72.4 0.0 0.0 27.6 48.0 0.3 0.0 51.7 8/8/94 308 47.6 0.3 0.0 52.1 56.1 0.4 0.0 43.4 42.0 0.0 0.0 57.9 8/29/94 329 38.9 0.4 1.7 59.0 52.3 0.0 0.0 47.7 41.0 0.0 0.0 59.0 9/26/94 357 45.7 0.4 0.0 53.9 52.3 0.0 0.0 47.7 43.6 0.0 0.0 56.4 10/17/94 378 45.5 0.0 0.0 54.4 52.1 0.0 0.0 47.9 40.4 0.4 0.0 59.2 10/28/94 389 35.6 0.4 1.4 62.4 36.0 0.4 1.3 62.2 10/31/94 392 30.3 0.7 2.2 66.7 26.3 0.6 3.4 69.6 11/4/94 396 25.5 0.6 2.5 71.4 57.7 0.0 0.0 42.3 18.3 0.4 4.1 77.0 11/10/94 402 16.8 0.3 0.0 82.8 11/14/94 406 27.7 0.0 0.0 72.3 53.5 0.0 0.0 46.5 12.7 0.0 0.0 87.3 11/21/94 413 18.9 0.9 3.5 76.6 6.9 0.7 4.7 87.6 12/23/94 445 14.7 0.7 3.3 81.2 50.3 0.5 0.0 49.2 5.1 0.5 5.5 88.8 1/9/95 462 13.1 0.5 0.0 86.4 51.3 0.0 0.0 48.7 4.2 0.6 7.5 87.6 1/16/95 469 17.2 0.4 2.5 79.8 47.6 0.0 0.0 52.4 4.9 1.1 8.8 85.1 1/23/95 476 17.9 0.6 0.0 81.5 37.8 0.4 0.0 61.7 6.4 0.6 6.7 86.3 1/30/95 483 15.9 0.9 3.7 79.5 32.1 0.7 0.0 67.1 5.8 0.7 6.5 87.0 2/13/95 497 13.5 0.9 0.0 85.5 27.7 0.6 11.2 60.5 5.1 0.8 7.4 86.8 2/27/95 511 12.1 1.0 3.9 82.9 31.2 0.2 18.4 50.2 6.3 1.8 27.1 64.7 3/13/95 525 10.1 0.0 4.0 85.8 22.7 0.0 10.9 66.3 3.9 0.9 15.3 79.9 3/27/95 539 11.4 0.7 3.8 84.0 25.0 0.5 0.0 74.4 5.8 1.2 0.0 93.0 4/3/95 546 12.3 0.7 0.0 87.0 25.2 0.0 0.0 74.7 5.8 0.0 8.7 85.5 4/10/95 553 21.3 0.0 0.0 78.6 31.0 0.0 0.0 69.0 15.2 0.0 4.8 79.9 4/17/95 560 27.9 0.0 0.0 72.0 39.8 0.0 0.0 60.2 25.7 0.0 0.0 74.3 4/24/95 567 33.9 0.0 0.0 66.1 41.8 0.0 0.0 58.1 30.9 0.0 0.0 69.1 5/8/95 581 35.2 0.9 0.0 63.8 42.1 0.7 0.0 56.8 35.3 0.6 0.0 64.1 5/26/95 599 41.5 0.0 0.0 58.5 44.5 0.0 0.0 55.5 40.7 0.0 0.0 59.2 6/26/95 630 43.8 0.0 0.0 56.2 43.5 0.0 0.0 56.5 43.5 0.0 0.0 56.5 Appendix G. Gas Characteristics Data G.2 Gas Production 291 oo CO ft! oo oo CM O co CO oo |v LO LO co s v CM co co Tf CO ft in co Tf io |v OO CO 2618 3031 3284 3376 4309 3993 4025 4222 4689 5062 5142 5314 5958 | 5956| 6444 | 6779| 5161 4665 4225 | 5537| 5936 5900 5479 5394 5884 5325 | 6076| 6853 9367 | 8293| 771/ iv 1727 i— Tf CM o CM LO Tf Tf CM IV 1174 v CO co o CO Tf O CT oo co CO CM in CO o IV O 3 Tf to |v oo CM oo 1025 oo 5! CO 1472 1003 co oo 1129 1377 1747 1747 1829 2333 | 2482 2693 | 2618 2054 1932 1741 | 3078 2397 2882 2527 2232 2452 2326 | 2432 2824 | 4659 | 3344 3067 co 6574 5256 57941 5044 6871 8167 6638 7316 6544| 56961 7418| 5601 | 6361| | 6295| 8189 8041 9783 9884 10931 11738 12146 11359 11318 10714 10230 | 11841 11570 10874 | 10118 9690 9991 | 8529 | 9124 9182 | 10840 | 8818 | 8184 to 16341 oo co iv oo LO CO o LO oo LO 11261 00 in co tv o oo CO 00 o co CM V to 00 LO CM CO co oo |v 1327 1612 1877 1853 2546 2349 | 2558 | 3030 | 3242 | 3590 | 3612 | 3673 | 4296 I 4066 4518 | 4619 3743 | 3770 3434 I 4764 | 4560 | 4737 | 4394 4296 | 4599 | 4171 | 4594 | 5087 | 7052 | 5842 | 5415 Tf 10061 10211 1619| co 8 13361 14811 1279| 1043| 1292| to oo j 1130] Tf 3 oo I 1405 o Tf to CO ft Tf iv o o o CO CM oo oo CO to to co |v Tf o | 1072 1883 | 1775 | 2050 | 3216 | 2776 | 2959 | 2261 | 1234 | 1340 m ft! 00 s | 1919 I 2992 CO o o o s CM CO Tf CM co 3 8 Tf |v co co LO co to OO CM 3 CO Tf oo co |v oo CM co m CO co co m o V co o> 0) 00 V oo 8 CM O CM CT CM Tf oo Tf o oo oo Tf CM to fv |v CM CO in CO CO 8! o in in o oo oo oo CM CO 00 IV co oo |v OO o 5) | 2104 | 1911 | 2635 | 2949 | 4581 | 2373 to CM 13361 o CO 00 LO Tf O LO LO LO OO co co co IV oo Tf to o |v Tf CM co co oo in O LO CM co co co CM co | 1139 oo Tf 00 | 1215 CM o 3 o | 1258 | 1510 | 1744 | 1802 cvi 00 | 1374 | 1416 | 1530 | 1647 | 1376 SOU I |v CO oo | 1980 | 1831 | 2116 | 2006 | 1763 | 2013 | 1703 | 2536 f 2590 | 4256 | 3714 ]3567 11731 co CM GO Tf co co co 11571 14631 Tf co |v co co co m co CO 8 00 1087| CM in Tf oo Tf |v oo m 00 \ 1494 | 1652 | 1619 | 1417 | 2638 | 2106 | 1998 | 2369 | 2355 | 3171 | 5783 | 2271 | 1969 [ 1197 [ 1742 | 2910 r 2131 | 3172 | 2498 | 3851 [ 3919 j 3839 | 3627 \ 2194 | 2615 | 2209 f 2850 | 3950 | 7387 | 5842 | 4428 o o o o LO CM IV OO 00 CO CO CM oo oo r— CO CT o co Tf oo TJ |v CM co oo LO o oo in | 1297 | 1321 | 1567 I 1220 | 2080 oo IV CM o | 1414 | 1755 | 1880 f 1926 \ 1511 [ 1841 | 1924 | 2127 I 2233 | 1767 | 1807 f 1573 | 2755 | 2379 | 2532 | 2545 | 2287 P2590 | 2286 I 2902 | 3223 | 5156 I 4458 | 4277 0> 15861 Iv in Tf CO co oo co fv |v LO oo r-CM OO CO i— oo IV OO in CM oo oo CM CM CO co 00 o v in m |v |v | 2483 | 2873 | 3227 [ 3247 | 4081 [ 4014 | 3925 r 4273 | 4417 | 4735 | 4466 | 4596 | 5606 | 5663 | 6236 | 6356 | 4310 | 4252 | 3924 | 5382 | 5628 | 5795 | 5479 | 5437 | 5842 I 5297 I 5859 | 6040 I 7382 I 6350 | 5976 CO 00 CO GO co IV co co CO O) oo CO Tf LO co O) co 00 in Tf co CT O 00 IV o m |v 00 00 oo to CM m to to CO |v | 2598 | 3032 I 3466 | 3464 f 4647 | 4506 | 4838 | 5172 | 5812 | 6264 | 6379 | 6362 | 7527 | 7458 | 8148 8474 | 6240 | 5997 | 5626 I 7394 | 8202 | 8665 I 8316 | 9026 | 9882 I 9650 I 10506 | 11213 I 13403 I 12646 | 12458 iv 19881 co o co CO oo IV o co Tf 00 in CO oo LO CM 00 CM CM CO in CO Tf oo o oo 0) CM rv Tf OO | 2156 | 3345 | 3816 | 4305 | 4303 | 5143 | 4682 | 4313 | 4541 | 4687 | 5036 | 5119 | 5139 | 5787 | 5969 | 6644 I 7639 | 7209 | 7188 | 7090 I 9701 | 9373 | 11901 I 11666 | 12290 | 13565 I 12347 I 13358 I 14972 I 19491 I 17232 | 16052 CO CO o IV co co co 1027J CO oo 00 1610| 20071 1134 CO OO co in 8! 8 1 1173! oo LO I 1146 IV ft! 00 | 2557 | 2015 | 3357 | 3569 | 4668 | 4062 | 4327 | 4893 | 5612 I 6434 I 6994 I 7631 I 11029 I 7622 | 10905 I 10973 | 8175 I 7777 | 7345 I 8966 I 9943 I 10216 I 9869 I 10110 I 11129 I 10852 I 10540 I 10661 I 13202 I 12647 | 12537 LO 17141 co LO 12171 CM CO co 17661 2140 I 14441 I 13361 I 1618 I 1476 I 1774 | 1171 I 1654 I 1994 | 2809 | 3361 | 3718 I 3974 I 5008 I 5083 I 5190 I 5783 I 6153 I 6714 0669 I I 7724 I 8097 I 8451 | 9178 I 9932 I 8278 I 7381 9869 I I 8652 I 9643 I 9452 I 8941 | 9065 I 9763 I 8793 I 9188 I 10645 I 14598 I 12819 | 11863 Tf o CO CO r-r-co Tf Tf CO CM CO o co CO 8 o o T? |v Tf s in to 00 |v CO 1— o in 8 I 2004 I 1979 I 2906 I 1179 j 1127 I 3228 I 3678 I 3808 I 4064 I 3837 I 4256 I 4459 I 4754 I 5053 I 4301 I 4013 | 3663 I 5128 I 5496 I 5630 I 5342 I 5319 I 5775 I 5186 I 5886 I 6367 I 8482 I 7336 I 6619 co 11101 o 0) CM o CM IO CO oo Tf o IV co co § ft! 8 IL66 iv oo 8 oo co oo Tf o o oo 00 CO oo I 1495 I 1644 I 1752 fv o I 1695 | 1575 I 1782 I 1970 I 2140 I 2098 I 2193 I 2668 I 2878 I 3397 I 3752 I 2682 I 1648 I 1489 I 2856 I 2183 I 3546 I 3365 I 3385 I 3685 I 3469 I 3857 I 4199 I 5517 I 4849 I 4688 CM 16051 LO CO Tf LO 00 00 LO oo 17701 18011 11281 |v oo 00 1199 I 1085 I 1312! 3 tv I 1238 1 1484 I 2093 I 2602 I 2718 I 2980 I 4053 I 4260 I 4568 I 5257 I 5750 I 6144 6099 I I 4632 I 4138 I 4542 oo oo 6904 I 6309 I 5857 I 7665 8785 I 9044 I 4216 I 13700 I 10169 I 9469 I 10232 I 11964 I 16627 I 15088 I 14520 23571 Tf IV O) 15711 12171 21841 2077 12641 CM LO OO 1197 00 3 1145 O in co Tf OO CO oo 1490 I 1809 I 1696 I 1632 I 2327 I 2106 I 1815 I 2192 oo Tf CM I 3034 I 3296 3423 4406 4617 4991 I 5147 3814 I 3528 I 3190 I 4519 4279 I 4423 I 4129 4013 I 4305 I 3905 4514 4979 I 7241 I 6268 6080 f I c? o o Time(day) 1 o IV Tf CM co CM in co CM Tf 00 Tf co in CT CO o |v rv |v Tf 00 CO oo oo 901 1 CM oo co CM 8 o Tf tv Tf Tf LO to oo co in IV CM oo oo oo co oo co o CM o CM IV CM Tf CM w CM 8 CM to Tf CM CM in CM CO in CM to co CM co IV CM o oo CM IV oo CM Tf 00 CM o co oo o co IGas produ Column #1 Date 10/4/93 10/11/93 10/18/93 10/25/93 11/1/93 co oo SS 11/15/93 CT CO 12/6/93 12/13/93 12/20/93 12/27/93 Tf co 1/10/94 1/17/94 Tf 9? 3 1/31/94 2/7/94 2/14/94 2/21/94 2/28/94 3/7/94 3/14/94 3/21/94 3/28/94 4/4/94 4/11/94 4/18/94 4/25/94 5/2/94 5/9/94 5/16/94 5/23/94 5/30/94 6/6/94 6/13/94 6/20/94 6/27/94 7/4/94 7/11/94 7/18/94 7/25/94 8/1/94 8/8/94 Appendix G. Gas Characteristics Data 292 8 8 si s Si is 3 is s SI a 5 8 S3 3 a s S3 a SI SI S3 8 8 8 8 8 8 8 a S3 8 a 8 8 8 a 8 8 SI 8 8 3 8 a a si s CJ) SI 8 8 a 3 a 3 Si 8 8! 3 3 5 a 8 3 3 5 8 co Sic. Si 8 c. m in cn CD CD co 

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