@prefix vivo: . @prefix edm: . @prefix ns0: . @prefix dcterms: . @prefix skos: . vivo:departmentOrSchool "Applied Science, Faculty of"@en, "Civil Engineering, Department of"@en ; edm:dataProvider "DSpace"@en ; ns0:degreeCampus "UBCV"@en ; dcterms:creator "Miller, Bradford Hale"@en ; dcterms:issued "2010-09-16T19:53:50Z"@en, "1988"@en ; vivo:relatedDegree "Master of Applied Science - MASc"@en ; ns0:degreeGrantor "University of British Columbia"@en ; dcterms:description """A nine month field and laboratory study was undertaken to measure, predict and model the variation of detected ammonia concentrations in landfill gas. An additional side study attempted to characterize organic trace contaminants found in landfill gas. The field project consisted of biweekly sampling of gas extraction wells from four Vancouver-area landfills for the analysis of NH₃-N in the gas and leachate. Methane and other common landfill gases were also analyzed. The wet chemical boric-acid sampling technique used in this study was estimated to have a ammonia gas recovery efficiency of 50 %. Other than a low recovery efficiency, problems encountered with this sampling technique was the high humidity and negative interferences inherent in the landfill gas. Laboratory analysis of the collected NH₃-N gas samples was by the automated phenate method, which could detect NH₃-N gas concentrations greater than 10 ppb. The NH₃-N concentrations in gas were found to exceed 600 ppb, but were more commonly in the 50 to 200 ppb range. In the statistical and graphical analysis, gas temperature and precipitation were found to correlate the most to the variation in ammonia gas concentration, while leachate ionic strength correlated strongest with most CH₄ % analysis. Prediction of both NH₃-N gas and CH₄ % by regression analysis was found to be suspect due to low R² values and non-normality of some data. Four different Henry's Law constants of ammonia gas were evaluated to help predict the concentration of NH₃-N in the gas phase. The combination of already measured NH₃-N leachate concentrations and Henry's Law constants yielded results that over and underpredicted measured NH₃-N gas data by 2000 fold or more. This leads the author to believe Henry's Law may not be applicable in a landfill environment due to non-equilibrium conditions coupling with various other reaction mechanisms. Comparison of landfill ammonia gas flux rates with total ammonia leachate flux rates in two of the four landfills yielded an insignificant gas flux rate of less than 0.03 % of the total leachate NH₃-N fluxes. The NH₃-N gas flux results were calculated from a spreadsheet emission model employing both convection and diffusion flow through the landfill cover. A comparison of the emission model results for the 20 ha Richmond landfill study area (3.862 kg/yr) compared favorably to the mass flux results determined from a simple gas generation mass balance model."""@en ; edm:aggregatedCHO "https://circle.library.ubc.ca/rest/handle/2429/28506?expand=metadata"@en ; skos:note "AMMONIA GAS DYNAMICS IN FOUR VANCOUVER AREA LANDFILLS By BRADFORD HALE MILLER B.S., U n i v e r s i t y of A r i z o n a , 1984 A THESIS SUBMITTED IN PARTIAL FULFILLMENT THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF CIVIL ENGINEERING We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA August 1988 ® Bradford Hale M i l l e r , 1988 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. The University of British Columbia Vancouver, Canada Department DE-6 (2/88) i i ABSTRACT A nine month f i e l d and l a b o r a t o r y study was undertaken to measure, p r e d i c t and model the v a r i a t i o n of detected ammonia concentrations i n l a n d f i l l gas. An a d d i t i o n a l side study attempted to c h a r a c t e r i z e organic t r a c e contaminants found in l a n d f i l l gas. The f i e l d p r o j e c t c o n s i s t e d of biweekly sampling of gas e x t r a c t i o n w e l l s from four Vancouver-area l a n d f i l l s f o r the a n a l y s i s of NH^-N i n the gas and l e a c h a t e . Methane and other common l a n d f i l l gases were a l s o analyzed. * The wet chemical b o r i c - a c i d sampling technique used i n t h i s study was estimated to have a ammonia gas recovery e f f i c i e n c y of 50 %. Other than a low recovery e f f i c i e n c y , problems encountered with t h i s sampling technique was the high humidity and negative i n t e r f e r e n c e s inherent i n the l a n d f i l l gas. Laboratory a n a l y s i s of the c o l l e c t e d NH^-N gas samples was by the automated phenate method, which could detect NH3-N gas c o n c e n t r a t i o n s greater than 10 ppb. The NH^-N c o n c e n t r a t i o n s in gas were found to exceed 600 ppb, but were more commonly in the 50 to 200 ppb range. In the s t a t i s t i c a l and g r a p h i c a l a n a l y s i s , gas temperature and p r e c i p i t a t i o n were found to c o r r e l a t e the most to the v a r i a t i o n in ammonia gas c o n c e n t r a t i o n , while leachate i o n i c s t r e n g t h c o r r e l a t e d strongest with most CH^ % a n a l y s i s . P r e d i c t i o n of both NH^-N gas and CH^ % by r e g r e s s i o n a n a l y s i s was found to be 2 suspect due to low R values and non-normality of some data. Four d i f f e r e n t Henry's Law constants of ammonia gas were evaluated to help p r e d i c t the c o n c e n t r a t i o n of NH^-N i n the gas phase. The combination of already measured NH^-N leachate c o n c e n t r a t i o n s and Henry's Law constants y i e l d e d r e s u l t s that over and underpredicted measured NH^-N gas data by 2000 f o l d or more. This leads the author to b e l i e v e Henry's Law may not be a p p l i c a b l e in a l a n d f i l l environment due to non-equilibrium c o n d i t i o n s c o u p l i n g with v a r i o u s other r e a c t i o n mechanisms. Comparison of l a n d f i l l ammonia gas f l u x rates with t o t a l ammonia leachate f l u x r a t e s i n two of the four l a n d f i l l s y i e l d e d an i n s i g n i f i c a n t gas f l u x r a t e of l e s s than 0.03 % of the t o t a l leachate NHg-N f l u x e s . The NH3~N gas f l u x r e s u l t s were c a l c u l a t e d from a spreadsheet emission model employing both convection and d i f f u s i o n flow through the l a n d f i l l cover. A comparison of the emission model r e s u l t s f o r the 20 ha Richmond l a n d f i l l study area (3.862 kg/yr) compared f a v o r a b l y to the mass f l u x r e s u l t s determined from a simple gas generation mass balance model. i v TABLE OF CONTENTS ABSTRACT i i LIST OF TABLES x i i LIST OF FIGURES xv ACKNOWLEDGEMENTS xx i CHAPTER 1 I n t r o d u c t i o n 1 1 . 1 Background 1 1.2 O b j e c t i v e s of Study 2 1.3 Scope of I n v e s t i g a t i o n 3 1 .4 Scope of Contents . . . . 5 1 . 4 . 1 . L i t e r a t u r e Review 5 1 1 4 . 2 . S i t e D e s c r i p t i o n and H i s t o r y 6 1 . 4 . 3 . Methodology 6 1 . 4 . 4 . D i s c u s s i o n of R e s u l t s . . . . 6 1 . 4 . 5 . Conclusions and Recommendations 6 1 . 4 . 6 . References 6 1 . 4 . 7 . Appendix 6 CHAPTER 2 Background and L i t e r a t u r e Review 2 . 1 . . L a n d f i l l C h a r a c t e r i s t i c s 7 2 . 1 . 1 . Leachate Pr o d u c t i o n 7 2 . 1 . 2 . L a n d f i l l Gas P r o d u c t i o n 7 2 . 1 . 2 . 1 . Decomposition of Refuse 7 2 . 1 . 2 . 2 . Temporal Stages i n Gas Production 10 V 2.1.3. F a c t o r s A f f e c t i n g Decomposition and 11 Gas Production 2.1.3.1. Refuse Composition 11 2.1.3.2. N u t r i e n t A v a i l a b i l i t y 13 2.1.3.3. Refuse Emplacement 15 2.1.3.4. Refuse P a r t i c l e S i z e 15 2.1.3.5 Hydrogeology of L a n d f i l l Area 16 2.1.3.6. L a n d f i l l Age 16 2.1.3.7. Gas Recovery System 16 2.1.3.8. O x i d a t i o n Reduction P o t e n t i a l 17 2.1.3.9. Moisture Content 18 2.1.3.10. Temperature 19 2.1.3.11. A l k a l i n i t y and pH 20 2.2. Review of F i e l d S t u d i e s 23 2.3. O f f s i t e Gas M i g r a t i o n 25 2.4. Gas C o l l e c t i o n Systems 28 2.4.1. C o l l e c t i o n 28 2.4.2. Pretreatment 31 2.4.3. Gas E x t r a c t i o n Parameters 33 2.4.3.1. E x t r a c t i o n w e l l Spacing 33 2.4.3.2. Gas E x t r a c t i o n and Production Rates 34 2.4.3.3. Refuse P e r m e a b i l i t y 35 2.4.3.4. I n t e r n a l Gas V e l o c i t y 36 2.5. Ammonia Gas i n L a n d f i l l s 37 2.5.1. P h y s i c a l P r o p e r t i e s of Ammonia Gas 37 2.5.2. Sources and Ambient Atmospheric Levels of NH3..38 v i 2.5.2.2. N a t u r a l Sources 38 2.5.2.2. Anthropogenic Sources 39 2.5.2.3. Ambient Atmospheric L e v e l s 39 2.5.2.4. A n a l y t i c a l Techniques 40 2.5.3. Ammonia Generation i n L a n d f i l l s 40 2.5.3.1 . Sources 40 2.5.3.2. Production of Ammonia 41 2.5.3.3. Ammonia Sinks 43 2.5.3.4. L a n d f i l l Ammonia Balance 43 2.5.4. F a c t o r s A f f e c t i n g Ammonia Movement 44 In L a n d f i l l 2.5.4.1. Mass T r a n s f e r i n Unsaturated Zone 44 2.5.4.2 Mass T r a n s f e r i n Saturated Zone... 49 2.5.4.3. Fu r t h e r Movement i n L a n d f i l l 50 CHAPTER 3 S i t e D e s c r i p t i o n and H i s t o r y 3.1. Matsqui - Clearbrook L a n d f i l l 52 3.1.1. L o c a t i o n 52 3.1.2. P h y s i c a l D e s c r i p t i o n 52 3.1.3. H i s t o r y and C h a r a c t e r i s t i c s of F i l l 52 3.1.4. Gas E x t r a c t i o n System.. 53 3.2. S t r i d e Avenue L a n d f i l l 58 • 3.2.1. L o c a t i o n 58 3.2.2. P h y s i c a l D e s c r i p t i o n 58 3.2.3. H i s t o r y and C h a r a c t e r i s t i c s of F i l l 59 3.2.4. Gas E x t r a c t i o n System 61 V l l 3.3. Richmond L a n d f i l l 63 3.3.1. L o c a t i o n 63 3.3.2. P h y s i c a l D e s c r i p t i o n 64 3.3.3. H i s t o r y and C h a r a c t e r i s t i c s of F i l l 64 3.3.4. Gas E x t r a c t i o n System 66 3.4. Premier S t r e e t L a n d f i l l 70 3.4.1. L o c a t i o n 70 3.4.2. P h y s i c a l D e s c r i p t i o n 70 3.4.3. H i s t o r y and C h a r a c t e r i s t i c s of F i l l 71 3.4.4. Gas C o l l e c t i o n System 73 CHAPTER 4 Methodology 4.1. F i e l d Methods - 75 4.1.1. Instrumentation and Technique 75 4.1.2. NH3-N Gas Sampling Technique 78 4.1.3. V o l a t i l e Organic Sampling 82 4.2. Laboratory Methods 84 4.2.1. Instrumentation and Technique 84 4.2.1.1. Leachate C o n s t i t u e n t s 84 4.2.1.2. S p e c i f i c C o n d u c t i v i t y 85 4.2.1.3. NH3-N D i s t i l l a t i o n - T i t r a t i o n A n a l y s i s . 8 5 4.2.1.4. Gas Chromatography/Mass Spectrometry....86 4.2.1.5. Methane Gas A n a l y s i s 87 4.2.2. Ammonia Gas A n a l y s i s 88 4.3. P r e c i p i t a t i o n S t a t i o n s 91 4.4. Basic Data Parameters Monitored 92 v i i i 4.5. Non-Basic Data Parameters 92 4.6. S t a t i s t i c a l A n a l y s i s Done on Parameters 93 4.4.1. L i n e a r B i v a r i a t e Regression 93 4.4.2. Pearson Product-Moment C o r r e l a t i o n 93 4.4.3. Kolmogorov-Smirnov Goodness of F i t Test 93 4.4.4. M u l t i p l e Regression A n a l y s i s 94 CHAPTER 5 R e s u l t s and D i s c u s s i o n 5.1. Ammonia Gas A n a l y t i c a l Technique 96 5.1.1. Problems Encountered on Autoanalyzer 96 5.1.2. I n t e r f e r e n c e s 99 5.1.3. D e t e c t i o n L i m i t 102 5.1.4. P r e c i s i o n 102 5.1.5. Recovery E f f i c i e n c y 103 5.2. Temporal and S p a t i a l V a r i a t i o n of Data 106 5.2.1. V a r i a t i o n i n C o l l e c t e d Data 106 5.2.2. Non-Metal Leachate C o n s t i t u e n t s 106 5.2.3. P r e c i p i t a t i o n 110 5.2.4. Temperature 115 5.2.5. O x i d a t i o n Reduction P o t e n t i a l 116 5.2.6. S t a t i c Gas Flow 119 5.2.7. N2/02 Gas R a t i o 125 5.3. V a r i a b l e s that A f f e c t Methane Gas Pet 129 5.4. V a r i a b l e s that A f f e c t Ammonia Gas C o n c e n t r a t i o n 132 5.4.1. I n t r o d u c t i o n 132 5.4.2. P r e c i p i t a t i o n 134 ix 5.4.3. NH3-N i n Leachate ^ 147 5.4.4. Leachate pH 148 5.4.5. Methane Flux 148 5.4.6. Gas Temperature 149 5.4.7. Other Parameters 154 5.5. L a n d f i l l Gas Organics 154 5.6. P r e d i c t i o n of NH3-N Gas Through Henry's Law 160 5.6.1. I n t r o d u c t i o n 160 5.6.2. Comparison of D i f f e r e n t Henry's Law Constants..161 5.6.2.1. C o r r e c t e d Vapor Pressure Method 161 5.6.2.2. Mole F r a c t i o n Method 171 5.6.2.3. Gibbs Free Energy Method 172 5.6.2.4. S o l u b i l i t y - E q u i l i b r i u m Method... 173 5.6.2.5. Summary of R e s u l t s 175 5.6.3. Reasons f o r Discrepancy i n P r e d i c t e d vs 177 Measured R a t i o 5.6.3.1. A n a l y t i c a l Technique 177 5.6.3.2. L a n d f i l l Unsaturated Zone 179 5.6.3.3. Volume D i l u t i o n E f f e c t 180 5.6.3.4. L a n d f i l l H e t e r o g e n i e t i e s 181 5.6.3.5. Non-Equilibrium L a n d f i l l Environment.... 182 5.6.3.6. Mass T r a n s f e r L i m i t a t i o n s 183 5.6.3.7. S o l u b i l i t y of Ammonia 183 5.6.3.8. L a n d f i l l Sinks 186 5.7. Mass Flux Emission of NH3-N Gas 187 5.7.1. I n t r o d u c t i o n 187 X 5.7.2. Model I n t r o d u c t i o n . ^ 188 5.7.2.1. Farmer's Model 188 5.7.2.2. Thibodeaux's Model 189 5.7.2.3. Assumptions f o r Models 190 5.7.2.4. L i m i t a t i o n s to Model ....191 5.7.3. Model Res u l t s of L a n d f i l l NH3-N Gas Fluxes 192 5.7.3.1. I n t r o d u c t i o n 192 5.7.3.2. D i s c u s s i o n of R e s u l t s 195 5.7.3.3. Comparison of Model R e s u l t s with 197 Gas Generation Mass Balance R e s u l t s 5.7.4. Summary of R e s u l t s 199 CHAPTER 6 Con c l u s i o n s and Recommendations 200 CHAPTER 7 References 208 APPENDICIES A.I. R e s u l t s of Gas P a r t i t i o n e r Accuracy R e s u l t s 218 A.2. R e s u l t s of Leakage T e s t s on Gas Sample V i a l s 218 A.3. Raw Data of 6.0 L/min Flow Recovery E f f i c i e n c y 219 A.4. Raw Data of 2.1 L/min Flow Recovery E f f i c i e n c y 219 A.5. Raw Data of 10.5 L/min Flow Recovery E f f i c i e n c y .219 A.6. R e s u l t s of pH Meter Comparison 220 A. 7. Summary Table of Q u a l i t y Assurance Te s t s 221 B. I. C a l c u l a t i o n of CH4 Flux 221 B.2. C a l c u l a t i o n of C02 Flux 221 B.3. C a l c u l a t i o n of L a n d f i l l Gas Density 221 x i B.4. C a l c u l a t i o n of ppb of NH3-N in L a n d f i l l Gas 222 B.5. C a l c u l a t i o n of Leachate Ionic Strength 222 B.6. C a l c u l a t i o n of Leachate A c t i v i t y C o e f f i c i e n t 222 B.7. C a l c u l a t i o n of Unionized F r a c t i o n Of Ammonia 223 B.8. E s t i m a t i o n of pKa 223 B.9. C a l c u l a t i o n of Aqueous Ammonia M o l a r i t y 224 B.10. E s t i m a t i o n of H1 From Vapor Pressure Method 224 B.11. E s t i m a t i o n of H2 From Mole F r a c t i o n Method 225 B.12. E s t i m a t i o n of H3 From Gibbs Free Energy 226 B.13. E s t i m a t i o n of H4 From S o l u b i l i t y - E q u i l i b r i u m Method...227 B.I 4. D e s c r i p t i o n and D e r i v a t i o n of Thibodeaux's Model 227 B.I 5. Sample C a l c u l a t i o n of Thibodeaux's Model 229 B. 16. Sample C a l c u l a t i o n of Gas Generation Mass Balance 229 Model C. 1. Weekly P r e c i p i t a t i o n Data For Three Weather Stations..231 D. I. Tables of Basi c Data Parameters i n Each Sample Well...232 E. I. Tables of Parameters C a l c u l a t e d From Basic Data 243 F. I. Table of P r e c i p i t a t i o n Used For S t a t i s t i c a l A n a l y s i s . . 2 52 F.2. R e s u l t s of Kolmogorov-Smirov Normality T e s t s 253 F.3. Matrix R e s u l t s of Pearson Product-Moment C o r r e l a t i o n s . 2 5 4 X I 1 LIST OF TABLES 2.1 S p a t i a l V a r i a t i o n i n T y p i c a l Refuse Compositions 11 2.2 Refuse E m p i r i c a l Formulas Obtained From L i t e r a t u r e 12 2.3 F a c t o r s A f f e c t i n g D i f f u s i o n 27 2.4 P h y s i c a l P r o p e r t i e s of Ammonia Gas 38 5.1 R e s u l t s of S i g n a l Response Comparison 97 5.2 R e s u l t s of Standard A d d i t i o n T e s t s 101 5.3 R e s u l t s of Recovery E f f i c i e n c y T e s t s 105 5.4 Non-Metal Leachate C o n s t i t u e n t s From Matsqui 108 5.5 Non-Metal Leachate C o n s t i t u e n t s From S t r i d e Ave 108 5.6 Non-Metal Leachate C o n s t i t u e n t s From Richmond 109 5.7 Non-Metal Leachate C o n s t i t u e n t s From Premier St 109 5.8 L a n d f i l l Gas VOC's Detected by GC-MS and Tenax Trap....156 P1 Premier St 5.9 L a n d f i l l Gas VOC's Detected by GC-MS and Tenax Trap....157 F5 Matsqui 5.10 L a n d f i l l Gas VOC's Detected by GC-MS and Tenax Trap 158 F3 Matsqui 5.11 L a n d f i l l Gas VOC's Detected by GC-MS and Tenax Trap....159 C6 Richmond 5.12 R e s u l t s of Henry's Law Comparison. 163 F1 , F2, F3 Matsqui 5.13 R e s u l t s of Henry's Law Comparison 164 F5, F8 Matsqui 5.14 R e s u l t s of Henry's Law Comparison 165 F2, F3, F6 S t r i d e Ave. x i i i 5.15 R e s u l t s of Henry's Law Ccmparison 166 F7, F8, 10B S t r i d e Ave. 5.16 R e s u l t s of Henry's Law Comparison 167 B8, D9 Richmond 5.17 R e s u l t s of Henry's Law Comparison 168 C6, G7 Richmond 5.18 R e s u l t s of Henry's Law Comparison 169 D.55, B.53 Richmond 5.19 R e s u l t s of Henry's Law Comparison 170 P1, P2 Premier S t . 5.20 Summary Matrix of Average Range of Predicted/Measured..175 NH3-N Gas R a t i o s f o r Each L a n d f i l l . 5.21 Standard Values Used For M o d e l l i n g NH3-N Gas 194 Emissions From L a n d f i l l s . 5.22 Comparing Annual NH3-N Gas Mass Fluxes For Both 196 L a n d f i l l s . 5.23 Comparison Between Gas and Leachate Annual 196 Fluxes For Both L a n d f i l l s . 5.24 Comparison of Model Versus Mass Balance F l u x 199 C a l c u l a t i o n s . xiv THIS IS A BLANK PAGE X V LIST OF FIGURES 2.1. L a n d f i l l Gas Percentages as a Fun c t i o n of Time 10 2.2 F a c t o r s A f f e c t i n g L a n d f i l l Gas Pro d u c t i o n 22 2.3 Example of T y p i c a l E x t r a c t i o n Well 32 2.4 M i c r o s c o p i c C r o s s - S e c t i o n Through L a n d f i l l Refuse 45 2.5 R e l a t i o n s h i p s of Mass T r a n s f e r at S a t u r a t e d - 51 Unsaturated L a n d f i l l Environment 3.1 S i t e L o c a t i o n Map Showing Major Waterways, Roads 54 and M e t r o p o l i t a n Area 3.2 L o c a t i o n Map Clearbrook-Matsqui L a n d f i l l 55 3.3 S i t e Map Clearbrook-Matsqui L a n d f i l l 56 3.4 L o c a t i o n Map S t r i d e Avenue L a n d f i l l 60 3.5 S i t e Map S t r i d e Avenue L a n d f i l l 62 3.6 L o c a t i o n Map Richmond L a n d f i l l 65 3.7 S i t e Map Richmond L a n d f i l l 70 3.8 L o c a t i o n Map Premier S t r e e t L a n d f i l l 72 3.9 S i t e Map Premier S t r e e t L a n d f i l l 74 4.1 Schematic of Sampling Apparatus .80 4.2 Indophenol Blue Reaction 89 4.3 Flow Diagram of Technicon Autoanalyzer II f o r 90 NH3-N A n a l y s i s 5.1 Comparison of S i g n a l Responses 98 5.2 Comparison of Weekly P r e c i p i t a t i o n From Weather 111 S t a t i o n s In Close P r o x i m i t y to L a n d f i l l s 5.3 Temporal V a r i a t i o n of Weekly P r e c i p i t a t i o n vs 113 NH3-N gas G7 Richmond x v i 5.4 Temporal V a r i a t i o n of Weekly P r e c i p i t a t i o n vs 113 NH3-N gas P2 Premier St 5.5 Temporal V a r i a t i o n of Weekly P r e c i p i t a t i o n vs 114 NH3-N gas F3 Matsqui 5.6 Temporal V a r i a t i o n of Weekly P r e c i p i t a t i o n vs 114 NH3-N gas F7 S t r i d e 5.7 Temporal Changes in Gas and Ambient Temperature 117 F2 Matsqui 5.8 Temporal Changes in Gas and Ambient Temperature 117 F7 S t r i d e 5.9 Temporal Changes i n Gas and Ambient Temperature 118 G7 Richmond 5.10 Temporal Changes in Gas and Ambient Temperature 118 P1 Premier 5.11 Gas Flow vs. Barometric Pressure B8 Richmond 120 5.12 Gas Flow vs. Barometric Pressure P2 Premier 120 5.13 Gas Flow vs. Barometric Pressure F8 S t r i d e 121 5.14 Gas Flow vs. Barometric Pressure F2 Matsqui 121 5.15 Gas Flow vs. Barometric Pressure F3 Matsqui 122 5.16 Gas Flow vs. Barometric Pressure F4 Matsqui 122 5.17 Well Flow vs. Hourly Time F1 Matsqui 126 5.18 L a n d f i l l Gas N2/02 Ratio vs. Time - Matsqui F1 and F3..127 5.19 L a n d f i l l Gas N2/02 Ratio vs. Time - S t r i d e F2 and F7...127 5.20 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 135 B8 Richmond x v i i 5.21 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 135 D9 Richmond 5.22 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 135 C6 Richmond 5.23 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 135 D.55 Richmond 5.24 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 136 F2 Matsqui 5.25 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 136 F5 Matsqui 5.26 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 136 F2 S t r i d e 5.27 Temporal V a r i a t i o n of Weekly P r e c i p . vs. NH3-N gas 136 F7 S t r i d e 5.28 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 137 B8 Richmond 5.29 Temporal V a r i a t i o n of pH vs. NH3-N gas B8 Richmond 137 5.30 Temporal V a r i a t i o n of CH4 Flu x v s . NH3-N gas 137 B8 Richmond 5.31 Temporal V a r i a t i o n of Gas Temp v s . NH3-N gas 137 B8 Richmond 5.32 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 138 D9 Richmond 5.33 Temporal V a r i a t i o n of pH vs. NH3-N gas D9 Richmond 138 5.34 Temporal V a r i a t i o n of CH4 F l u x v s . NH3-N gas 138 D9 Richmond x v i i i 5.35 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 138 D9 Richmond 5.36 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 139 C6 Richmond 5.37 Temporal V a r i a t i o n of pH vs. NH3-N gas C6 Richmond 139 5.38 Temporal V a r i a t i o n of CH4 Flux vs. NH3-N gas 139 C6 Richmond 5.39 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 139 C6 Richmond 5.40 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 140 D.55 Richmond 5.41 Temporal V a r i a t i o n of pH v s . NH3-N gas D.55 Richmond...140 5.42 Temporal V a r i a t i o n of CH4 Flu x vs. NH3-N gas 140 D.55 Richmond 5.43 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 140 D.55 Richmond 5.44 Temporal V a r i a t i o n of NH3-N Leachate v s . NH3-N gas 141 F2 Matsqui 5.45 Temporal V a r i a t i o n of pH vs. NH3-N gas F2 Matsqui 141 5.46 Temporal V a r i a t i o n of CH4 F l u x vs. NH3-N gas 141 F2 Matsqui 5.47 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 141 F2 Matsqui 5.48 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 142 F5 Matsqui 5.49 Temporal V a r i a t i o n of pH vs. NH3-N gas F7 Matsqui 142 x i x 5.50 Temporal V a r i a t i o n of CH4 Flux vs. NH3-N gas ^...142 F7 Matsqui 5.51 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 142 F7 Matsqui 5.52 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 143 F2 S t r i d e 5.53 Temporal V a r i a t i o n of pH vs. NH3-N gas F2 S t r i d e 143 5.54 Temporal V a r i a t i o n of CH4 Flux vs. NH3-N gas 143 F2 S t r i d e 5.55 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 143 F2 S t r i d e 5.56 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 144 F7 S t r i d e 5.57 Temporal V a r i a t i o n of pH vs. NH3-N gas F7 S t r i d e 144 5.58 Temporal V a r i a t i o n of CH4 Flux vs. NH3-N gas ....144 F7 S t r i d e 5.59 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 144 F7 S t r i d e 5.60 Temporal V a r i a t i o n of NH3-N Leachate vs. NH3-N gas 145 P2 Premier 5.61 Temporal V a r i a t i o n of pH vs. NH3-N gas P2 Premier 145 5.62 Temporal V a r i a t i o n of CH4 Flux vs. NH3-N gas 145 P2 Premier 5.63 Temporal V a r i a t i o n of Gas Temp vs. NH3-N gas 145 P2 Premier 5.64 Regression P l o t of Gas Temp vs. NH3-N gas Matsqui 152 5.65 Regression P l o t 5.66 Regression P l o t 5.67 Regression P l o t xx of Gas Temp vs. NH3-N of Gas Temp vs. NH3-N of Gas Temp vs. NH3-N gas S t r i d e Ave...152 gas Richmond 153 gas Premier S t . . . 153 x x i ACKNOWLEDGEMENTS Th i s research was supported by a grant from the N a t u r a l Science and En g i n e e r i n g Research C o u n c i l (NSERC). For f i e l d - r e l a t e d a c t i v i t i e s , many thanks go to the f o l l o w i n g persons: Ron Forsythe of the Matsqui. M u n i c i p a l D i s t r i c t , Bob Rasmussen of the North Vancouver M u n i c i p a l D i s t r i c t and most of the s t a f f at E.H. Hanson & A s s o c i a t e s such as E l s o n , Greg, Mike and e s p e c i a l l y Len Hanson, who l e n t me h i s four wheel d r i v e jeep f o r sampling up on the \"world's l a r g e s t l a n d f i l l sandtrap\", the Richmond L a n d f i l l . For l a b o r a t o r y a c t i v i t i e s , s p e c i a l thanks go to Susan L i p t a k , Paula Parkinson and Romy So of the UBC Environmental E n g i n e e r i n g Lab who.provided me with some h e l p f u l h i n t s and input on my a n a l y t i c a l technique. Tim Ma, the s p e c i a l i s t f o r the UBC A p p l i e d Science GC/MS l a b o r a t o r y , i s a l s o thanked f o r h i s e x p e r t i s e i n sampling and! a n a l y s i s of the l a n d f i l l gas o r g a n i c s . My a d v i s o r , Jim Atwater i s a l s o acknowledged f o r h i s o r g i n a l idea of research and general guidance throughout the study. Two inanimate o b j e c t s worth acknowledging are the weather and computer systems, which i n most, cases were c o o p e r a t i v e d u r i n g the study. •;• Last but not l e a s t , i s very s p e c i a l thanks to my f i a n c e ' Lene C h r i s t i a n s e n , who helped with some of the tedious data and text input while t o l e r a t i n g my many temper tantrums dur i n g the p r e p a r a t i o n of t h i s manuscript. 1 CHAPTER 1 1. INTRODUCTION 1.1. BACKGROUND Most l a n d f i l l gas re s e a r c h has con c e n t r a t e d on stu d y i n g the dynamics and movement of methane gas. S t u d i e s of t h i s nature have mostly focused at a l y s i m e t e r - s c a l e . Recently, a p o r t i o n of t h i s r e s e a r c h has s h i f t e d i n t o the f i e l d sampling a c t u a l l a n d f i l l gas, mainly f o r the purpose of q u a n t i f y i n g and c h a r a c t e r i z i n g the t r a c e gas components; p r i m a r i l y the organic . contaminant . f r a c t i o n . T h i s study does c h a r a c t e r i z e v o l a t i l e organic contaminants i n samples, but co n c e n t r a t e s mainly on the a n a l y s i s of an i n o r g a n i c component, namely ammonia gas. Very few i n v e s t i g a t i o n s have documented a r e l e a s e of ammonia gas from l a n d f i l l s . Authors such as Tanasci.(1982) and Farquhar and Rovers (1973). \"mention ammonia as a t r a c e component i n l a n d f i l l gas, but present no q u a n t i t a t i v e measurement to s u b s t a n t i a t e t h e i r c l a i m . Ham (1979) r e p o r t e d a c o n c e n t r a t i o n of 0.71 ppb of NH^-N i n the l a n d f i l l gas condensate, but does not mention the a n a l y t i c a l technique used to determine t h i s c o n c e n t r a t i o n . The most promising study was by Winter (1979) who repor t e d c o n c e n t r a t i o n s of 0 to 350 ppb i n l a n d f i l l gas. U n f o r t u n a t e l y , Winter's r e p o r t does not mention the a n a l y t i c a l technique used. Al-Omar et a l . (198.5) r e p o r t e d that atmospheric mean and maximum NH^-N l e v e l s of 13 ppb to 174 ppb were measured around an open dump s i t e in Baghdad, I r a q . Ham (1979) mentions that the 2 BKK c o - d i s p o s a l s i t e i n West Covina, CA has c o n s i d e r e d c o n s t r u c t i o n of an ammonia s y n t h e s i s p l a n t i n - l i n e with t h e i r planned l a n d f i l l gas c o l l e c t i o n system. While there have been numerous s t u d i e s done on e s t i m a t i n g the mass f l u x of NH^-N from l a n d f i l l l e a c h a t e (Cameron, 1979, Atwater, 1980 and Jasper and Atwater, 1985), to t h i s author's knowledge, there have been no p r e v i o u s attempts to estimate the mass f l u x of ammonia l o s t through the gas phase. T h i s l o s s c o u l d c o n c e i v a b l y be s i g n i f i c a n t i f the proper chemical c o n d i t i o n s f a v o r i n g ammonia v o l a t i l i z a t i o n ( i e , high pH, high temp, hig h NH^-N i n leachate) were appparent in the l a n d f i l l . In a recent paper ( B a c c i n i et a l . , 1987), Swiss r e s e a r c h e r s have estimated element mass f l u x e s from both the l a n d f i l l l e a c h a t e and gas i n an attempt to c o r r e l a t e these element f l u x e s to r e l a t i v e l a n d f i l l age. While B a c c i n i et a l . presents an e s t i m a t i o n f o r l e a c h a t e n i t r o g e n f l u x , he f a i l s to estimate the n i t r o g e n f l u x l o s t through the gas phase v i a ammonia v o l a t i l i z a t i o n . 1.2. OBJECTIVES OF STUDY T h i s study was undertaken to improve the data base concerning trace, components in l a n d f i l l gas and to determine whether the ammonia gas f l u x c o n s t i t u t e s a s u b s t a n t i a l percentage of n i t r o g e n f l u x through a l a n d f i l l . I n c l u d i n g the above, the o b j e c t i v e s of t h i s study are l i s t e d below: A. To develop a simple, f a s t and r e l i a b l e a n a l y t i c a l technique to measure the c o n c e n t r a t i o n of NH^-N i n l a n d f i l l gas. B. I n v e s t i g a t e the f a c t o r s that c o u l d a f f e c t the temporal 3 v a r i a t i o n of NH^-N and methane c o n c e n t r a t i o n s i n l a n d f i l l gas. C. Develop a s t a t i s t i c a l model to h e l p p r e d i c t NH^-N c o n c e n t r a t i o n and methane percent from c o l l e c t e d data. D. Determine whether one can apply documented values of Henrys Law constants to p r e d i c t NH^-N gas c o n c e n t r a t i o n s given a known NH^-N c o n c e n t r a t i o n i n the l e a c h a t e . E. Determine i f NH^-N mass f l u x i n the l a n d f i l l gas i s a s u b s t a n t i a l f l u x component when compared to known mass f l u x e s of NH3-N i n l e a c h a t e . F. Determine q u a l i t a t i v e l y the types of. organic contaminants that e x i s t i n the l a n d f i l l gas. 1.3. SCOPE OF INVESTIGATION : To s a t i s f y the above o b j e c t i v e s , a nine month f i e l d and l a b o r a t o r y p r o j e c t was undertaken, beginning i n J u l y , 1987 and f i n i s h i n g i n e a r l y A p r i l of 1988. The l e n g t h of the.study p e r i o d was governed by one; the attempt to monitor the l a n d f i l l environment dur i n g a f u l l seasonal change and two; to gather enough data to get 15 sample p e r i o d s from each l a n d f i l l . The number of sample p e r i o d s was c o n s i d e r e d optimal f o r doing the s t a t i s t i c a l and m o d e l l i n g study d i s c u s s e d l a t e r i n the t h e s i s . The f i e l d study c o n s i s t e d of sampling gas e x t r a c t i o n w e l l s fo r l e a c h a t e and gas at four Vancouver-area l a n d f i l l s . The samples were taken bi-weekly from each l a n d f i l l . Other data taken d u r i n g f i e l d sampling i n c l u d e d : water l e v e l s , s t a t i c gas flow, a i r , gas and l e a c h a t e temperature, pH of the l e a c h a t e , and barometric p r e s s u r e . The t r a c e organic contaminant f r a c t i o n of 4 the l a n d f i l l gas was sampled by Tenax GC t r a p s d u r i n g three sample dates. The four l a n d f i l l s s t u d i e d were Matsqui, S t r i d e Avenue, Richmond and Premier S t r e e t . The reasons these four l a n d f i l l s were s e l e c t e d are s t a t e d below: A. L a n d f i l l s were completed and a c c e s s i b l e by automobile. B. L a n d f i l l s had a c c e s s i b l e gas c o l l e c t i o n w e l l s f o r l e a c h a t e and gas sampling. C. C o l l e c t i o n w e l l s had i n d i v i d u a l s h u t - o f f v a l v e s to i s o l a t e from any on-going system vacuum while sampling. D. L a n d f i l l s had a v a r i e t y of cover m a t e r i a l . E. L a n d f i l l s had a v a r i e d age and c o n s t r u c t i o n h i s t o r y . The l a b o r a t o r y study c o n s i s t e d of analyzing, the gas and leachate v a l u e s f o r CH 4, C0 2, N 2 ' °2 P e r c ^ n t a 9 e s ' NH^-N i n the gas, NH^-N and s p e c i f i c c o n d u c t i v i t y i n the l e a c h a t e . A l s o , . a n a l y s i s of the non-metal c o n s t i t u e n t s from each l e a c h a t e -c o n t a i n i n g sample w e l l was done twice d u r i n g the study. The l e a c h a t e was analyzed f o r a l k a l i n i t y , COD, t o t a l and organic carbon, t o t a l v o l a t i l e a c i d s , and t o t a l and v o l a t i l e s o l i d s . The ammonia gas samples were analyzed by the automated phenate method. A f t e r sampling, the trapped l a n d f i l l gas organic contaminants were analyzed by a GC/MS. The c o l l e c t e d data was analyzed i n three d i f f e r e n t steps beginning with the g r a p h i c a l and s t a t i s t i c a l a n a l y s i s . In the s t a t i s t i c a l a n a l y s i s , c o l l e c t e d data was checked f o r normal d i s t r i b u t i o n and f u r t h e r analyzed by product-moment c o r r e l a t i o n , and b i v a r i a t e and m u l t i p l e r e g r e s s i o n . T h i s was done i n an attempt to e x p l a i n or p r e d i c t the temporal and s p a t i a l v a r i a t i o n of NH3\"N and CH 4 i n l a n d f i l l gas. The second step attempted to compare four d i f f e r e n t ammonia gas Henry's Law con s t a n t s f o r t h e i r p o t e n t i a l to be used as a p r e d i c t i v e t o o l f o r NH^-N gas when the NH^-N leachate c o n c e n t r a t i o n i s known. The l a s t step was to estimate l a n d f i l l NH3-N mass f l u x e s from the gaseous phase through a simple emission model and compare these e s t i m a t i o n s with documented e s t i m a t i o n s of NH^-N mass f l u x e s i n l a n d f i l l l e a c h a t e . T h i s a n a l y s i s was attempted to observe i f any s u b s t a n t i a l p r o p o r t i o n of NH^-N was being l o s t i n the gas phase r e l a t i v e to the mass l o s t i n the l e a c h a t e . 1.4. SCOPE OF CONTENTS 1.4.1. LITERATURE REVIEW A l a r g e l i t e r a t u r e review was undertaken i n t h i s t h e s i s because of the breadth of t o p i c s that had to be addressed concerning l a n d f i l l gas and. ammonia movement i n l a n d f i l l s . : The l i t e r a t u r e review f i r s t d e s c r i b e s some b a s i c c h a r a c t e r i s t i c s i n l a n d f i l l l e achate and gas.. The review then proceeds i n t o a d e t a i l e d d i s c u s s i o n of the b i o l o g i c a l and p h y s i c a l f a c t o r s a f f e c t i n g decomposition and r e s u l t a n t l a n d f i l l gas p r o d u c t i o n . T e c h n o l o g i c a l aspects of gas recovery systems are then b r i e f l y presented. The f i n a l portion- of .'-the l i t e r a t u r e review focuses p r i m a r i l y on d i s c u s s i n g the p r o p e r t i e s , sources, s i n k s and mass t r a n s f e r of ammonia w i t h i n the l a n d f i l l environment. 1.4.2. SITE DESCRIPTION AND HISTORY 6 Presented i n t h i s chapter are d e s c r i p t i o n s of the l a n d f i l l l o c a t i o n , and the p h y s i c a l and h i s t o r i c a l a spects of each one. A s e c t i o n i s devoted to d e s c r i b i n g each of the l a n d f i l l ' s gas e x t r a c t i o n system and why c e r t a i n w e l l s were chosen to sample. 1.4.3. METHODOLOGY In d e t a i l , the f i e l d , l a b o r a t o r y and s t a t i s t i c a l methods used i n the study are d i s c u s s e d i n t h i s c h a pter. 1.4.4. DISCUSSION OF RESULTS Beginning t h i s chapter, i s a d i s c u s s i o n of the data from the a n a l y s i s of the NH^-N gas a n a l y t i c a l technique. Included are the r e s u l t s from determining i n t e r f e r e n c e s , d e t e c t i o n l i m i t , recovery e f f i c i e n c y and l a s t l y , an e v a l u a t i o n of the p r a c t i c a l i t y of t h i s technique. F o l l o w i n g the a n a l y t i c a l d i s c u s s i o n i s a g r a p h i c a l and s t a t i s t i c a l p r e s e n t a t i o n of a l l data with the emphasis on how v a r i o u s parameters c o n t r o l NH^-N and CH^ gas c o n c e n t r a t i o n s i n l a n d f i l l s . Immediately f o l l o w i n g the above i s a b r i e f s e c t i o n p r e s e n t i n g the r e s u l t s of the organic t r a c e study on the sampled l a n d f i l l gas. Fo l l o w i n g the t r a c e organic r e s u l t s , are d i s c u s s i o n s about the l a s t two study o b j e c t i v e s ; comparison of Henry's Constants and e s t i m a t i o n of NH^-N gas f l u x e s . 1.4.5. CONCLUSIONS AND RECOMMENDATIONS 1.4.6. REFERENCES 1.4.7. APPENDIX 1' CHAPTER 2 2. BACKGROUND AND LITERATURE REVIEW 2.1. LANDFILL CHARACTERISTICS 2.1.1. LEACHATE PRODUCTION The m a j o r i t y of l a n d f i l l l e a c h a t e i s generated a f t e r the moisture h o l d i n g c a p a c i t y ( f i e l d c a p a c i t y ) of the refuse i s exceeded. T h i s u s u a l l y happens d u r i n g p r e c i p i t a t i o n i n f i l t r a t i o n . F i e l d c a p a c i t y of r e f u s e has been s t u d i e d i n l y s i m e t e r s and has u n i t s of e i t h e r % moisture content (Metry, 1980 found 40 %) or amount of p r e c i p i t a t i o n one has to apply at the s u r f a c e to reach f i e l d c a p a c i t y i n a given depth of r e f u s e m a t e r i a l . Qasim and B u r c h i n a l (1970) found that about 13.5 cm of water c o u l d be p l a c e d per meter depth of r e f u s e above the r e f u s e ' s e x i s t i n g moisture content. L a n d f i l l l e a c h a t e i s a l s o produced from groundwater i n t r u s i o n , water from m i c r o b i a l decomposition and a p p l i c a t i o n of l i q u i d waste m a t e r i a l s l i k e chemical, sewage or s e p t i c sludges. F a c t o r s that a f f e c t l a n d f i l l l e a c h a t e p r o d u c t i o n i n c l u d e f o l l o w i n g : p r e c i p i t a t i o n , mean annual temperature, e v a p o t r a n s p i r a t i o n , r u n o f f , l a n d f i l l cap m a t e r i a l (e.g. p o r o s i t y , p e r m e a b i l i t y , f i e l d c a p a c i t y ) , r e f u s e d e n s i t y , i n i t i a l moisture content i n r e f u s e , and depth of l a n d f i l l ( L e c k i e , 1979) . 2.1.2. LANDFILL GAS PRODUCTION 2.1.2.1. DECOMPOSITION OF REFUSE Once s o l i d wastes are p l a c e d i n l a n d f i l l s , a e r o b i c b i o l o g i c a l a c t i v i t y immediately begins to degrade the organic waste f r a c t i o n . T h i s a e r o b i c phase r e s u l t s i n a c c e l e r a t e d waste c o n s o l i d a t i o n , high i n t e r n a l temperatures and produces l a r g e volumes of carbon d i o x i d e gas and degraded r e s i d u a l o r g a n i c s (Ham e t . a l . 1979). T h i s C0 2 gas \"bloom\" was f i r s t r e f e r r e d by Enginee r i n g - S c i e n c e (1961) and can reach up to 90 % volume i n t h i s i n i t i a l phase. T h i s a e r o b i c phase l a s t s f o r a short p e r i o d of time as an oxygen d e f i c i t b u i l d s up c r e a t i n g semi-anaerobic c o n d i t i o n s ; c o n d i t i o n s which f a c u l t a t i v e anaerobes can then begin to metabolize and grow. The dominant anaerobic phase begins s h o r t l y t h e r e a f t e r when a fauna of o b l i g a t e anaerobes reach l a r g e numbers w i t h i n the re f u s e . T h i s longstanding anaerobic phase i s c h a r a c t e r i z e d by Lawrence and McCarty (1964) as i n v o l v i n g three phases of b i o l o g i c a l a c t i v i t y from two p h y s i o l o g i c a l l y d i f f e r e n t b a c t e r i a l p o p u l a t i o n s (Toerien and Huttingh, 1969). The three stages are h y d r o l y s i s , a c i d formation, and methane formation. The f i r s t b a c t e r i a l p o p u l a t i o n i s r e f e r r e d to as the non-methanogenic organisms and are r e s p o n s i b l e f o r the f i r s t two stages of h y d r o l y s i s and a c i d formation. These anaerobes hydrolyze and metabolize the organic r e f u s e s u b s t r a t e of carbohydrates, f a t s , p r o t e i n s and c e l l u l o s e by t h e i r own enzymes i n t o end-products of mainly s a t u r a t e d f a t t y a c i d s with l e s s e r amounts of carbon d i o x i d e , ammonia> a l c o h o l s and ketones (Toerien and Huttingh, 1969). Songonuga (1969) i d e n t i f i e d the main endproduct a c i d s to be a c e t i c , p r o p i o n i c , b u t y r i c , v a l e r i c and 9 c a p r o i c when sampling r e f u s e a f t e r 2 years of emplacement. The d i s s o c i a t e d forms of these a c i d s c o u l d account f o r approximately 75 % of the anions found i n a given leachate (Songonuga, 1969). B a c i l l u s and more l i k e l y C l o s t r i d i a sp. appear to be the dominant non-methanogen fauna (Thompson, 1969). As these h y d r o l y z e r s continue to s o l u b i l i z e s a l t s and organic m a t e r i a l , the a l k a l i n i t y i n c r e a s e s enough to where methanogens can slowly a s s e r t themselves. The b a c t e r i a a c t i v e i n t h i s stage are g e n e r a l l y c o n s i d e r e d to be from the genus Methanobacterium, which r e q u i r e s t r i c t anaerobic c o n d i t i o n s and a redox p o t e n t i a l (Eh) of l e s s than -200 mV (Farquahar and Rovers, 1973). These methanogens o b t a i n energy f o r growth from two r e a c t i o n s . The f i r s t i s methane formed by an e i g h t - e l e c t r o n r e d u c t i o n of C0 2 by gas, which produces ample energy f o r growth as i n d i c a t e d by a negative standard f r e e energy change of -136 kj/mol (Large, 1982). The second r e a c t i o n i n v o l v e s the cleavage of a c e t i c a c i d (CH^COOH) i n t o CH 4 and C0 2 by a c e t a t e d e c a r b o x y l a t i o n (Farquhar and Rovers, 1973). The two r e a c t i o n s are shown below: C02 Reduction C0 2 + 4H 2 > CH 4 + 2H 20 Acetate D e c a r b o x y l a t i o n 2CH3COOH > 2CH 4 + 2C0 2 From studying r e s u l t s on anaerobic d i g e s t i o n of sewage sludge, Zehnder (1978) concludes that about ; 70 % of the methane produced o r i g i n a t e s from a c e t a t e d e c a r b o x y l a t i o n while the other 30 % i s d e r i v e d from CO, r e d u c t i o n (from Schumacher, 1983). 10 2.1.2.2. TEMPORAL STAGES IN GAS PRODUCTION Farguhar and Rovers (1973) designed a g r a p h i c a l p r e s e n t a t i o n of t h e i r four stages in gas p r o d u c t i o n . T h i s i s shown i n F i g u r e 2.1 where gas composition i s a f u n c t i o n of time a f t e r r e f u s e emplacement. T h i s conceptual gas production model assumes that an anaerobic environment c o u l d be achieved and maintained a f t e r refuse emplacement. The four phases i d e n t i f i e d were: I A e r o b i c ; II Anaerobic Non-Methanogenic; III Anaerobic Methanogenic Unsteady; IV Anaerobic Methanogenic Steady. FIGURE 2.1 - L a n d f i l l Gas Percentages as a'Function of Time ( Figure modified from Farquahar and Rovers, 1973) H u ^ NON-METHANOGENIC METHANOGENIC STAGES Completion time for phases I,II and III v a r i e s from as l i t t l e as 180 days (Ramaswamy, 1970) to 500 days (Beluche, 1968). 11 In the steady s t a t e phase IV, l a n d f i l l gas c o n c e n t r a t i o n s are g e n e r a l l y around 55 % CH 4, 40 % C0 2, with the r e s t being N 2, 0 2, H 2, Argon, Ammonia and other t r a c e gases made up mostly of hydrocarbons. 2.1.3. FACTORS AFFECTING DECOMPOSITION AND GAS PRODUCTION 2.1.3.1. REFUSE COMPOSITION Composition of refuse w i l l a f f e c t the l a n d f i l l decomposition r a t e , r e l a t i v e percentages of CH^ and C0 2, and methane pr o d u c t i o n r a t e s . There are la r g e v a r i a t i o n s i n refuse composition as a fun c t i o n of geography and l i f e s t y l e . Table 2.1 presents some common refuse compositions from mostly around North America. The most r e a d i l y degradable p o r t i o n of refuse are the sum of p u t r e s c i b l e s (Food +. Garden Wastes), paper, c l o t h , and f i n e s which in Table 2.1, g e n e r a l l y account for 70 - 75 % wet weight of the refuse f r a c t i o n . TABLE 2.1 - S p a t i a l D i f f e r e n c e s i n Refuse Compositions H a i f a Sonoma Pennsy 1 • Water loo Northham. U.S. D a v i s West L a f . Vane. C i n c i n a t I s r a e ] C a l i f . van i a Ontar io E n g l a n d Average C a l i f . I n d i a n a B.C . on i o ITEM Raveh Lecfc i e Remson Rovers Rees Sm i t h Tchobanag B e l 1 B i r d & H. P f e f f e r ================= ( 1979) (1979) (1968) (1973) (I960) ( 1975) (1977) ( 1963) ( 1978 ) ._ . (1974) PUTRESCIBLES 54 . 7 21.1 15 . 0 34 . 9 24.8 24.8 23 . 8 24 .0 25. 0 2 5 . 0 PLASTICS 4 .4 4 .6 3.8 3.2 4 .8 6 . 5 2.6 2. 1 2. 2 2 0 PAPER AND CLOTH 30.6 42 . 3 59 . 4 41.4 38 . 7 39.4 5 0 . 5 42 . 9 38. 9 49.0 WOOD 3.2 1 .0 4 . 2 1 . 1 • • 3.7 3.5 2.4 14 . 9 2 . 0 METALS 3. t 9 . 0 '•5 7. 1 6 . 9 10. 1 11.0 8.0 8. 2 8 . 0 GLASS 3.0 10.9 8 . 5 12. 1 8.2 1 0 . 0 7 . 5 6.':o 7 . 2 6 . 0 FINES - - 8 .3 1 . 7 0 . 2 12.3 - - • - • 1 .0 - 6 . 0 INORGANIC • • 2.8 0 . 9 • - 1.5 1. 1 3. 1 2 . 0 UNCLASSIFIED 4.3 0.5 3. 6 Note: PUTRESCIBLES i n c l u d e food and garden waste • I n e r t was c o n s i d e r e d UNCLASSIFIED waste items 12 In the f u t u r e , as more p l a s t i c s are produced, there w i l l be a l e s s e r p r o p o r t i o n of r e a d i l y degradable refuse a v a i l a b l e to the b a c t e r i a . T h e o r e t i c a l p r o d u c t i o n of CH 4 and C0 2 gas can. be estimated from an elemental a n a l y s i s performed on the r e f u s e . T h i s i s done by e i t h e r c a l c u l a t i n g the volume pr o d u c t i o n of gas per mass of component (e.g. carbohydrates, f a t s , p r o t e i n s , etc.) (See Emcon Assoc., 1980), or by e s t i m a t i n g a volume or molar percentage of gas from a given e m p i r i c a l formula. Some e m p i r i c a l formulas found or c a l c u l a t e d from the l i t e r a t u r e are presented i n Table 2.2. I n s p e c t i o n of t h i s t a b l e shows a f a i r l y constant r a t i o between H and C, which i s i n c o n t r a s t to the r a t i o of these two elements and n i t r o g e n . T h i s wide range of s t o c h i o m e t r i c r a t i o s i s a r e s u l t a n t of the wide v a r i a t i o n i n the r e f u s e composition r e p o r t e d by these authors. T h i s d i f f e r e n c e c o u l d have a profound e f f e c t on how much ammonia w i l l e x i s t i n the l a n d f i l l l e a c h a t e and gas phase. TABLE 2.2 - Refuse E m p i r i c a l Formulas Obtained From the L i t e r a t u r e . REFERENCE EMPIRICAL FORMULA Rees ( 1 980) C g 4 H g 7 0 3 3 ..N Tchobanoglous (1977) C 5 7 H g 4 0 3 g N 1 Gibs (1982) a f t e r B e l l (1963) C84 H120 °53 N1 Emcon Assoc. (1980) C g g H 1 4 g 0 5 g E s t i m a t i n g the volume percentages of gas can be done by s u b j e c t i n g an e m p i r i c a l waste formula ( C r ^ a ^ b * ^ to complete 1 3 anaerobic degradation of end-products of CH 4, CO,,, c e l l m a t e r i a l , ammonia and bi c a r b o n a t e a l k a l i n i t y (Emcon Assoc., 1980)., T h i s r e a c t i o n i s shown below: C H O, N + (2n + c - b - 9sd/20 - de/4)H o0 = n a D c ^ (de/8)CH 4 + (n - c -.sd/5 - de/8)C0 2 + (sd/20)C 5H ?O 2N + (c - :sd/20)NH 4+ + (c - sd/20)HCO 3~ Where d = 4n + a - 2b - 3c s = the f r a c t i o n of COD s y n t h e s i z e d or c o v e r t e d to c e l l s (= 0.04) e = the f r a c t i o n of COD s y n t h e s i z e d or converted to CH 4 (1 - s) 2.1.3.2. NUTRIENT AVAILABILITY Somewhat r e l a t e d to r e f u s e composition i s the a v a i l a b i l i t y of n u t r i e n t s f o r b i o l o g i c a l uptake. N u t r i e n t s important f o r l a n d f i l l microbe growth i n c l u d e : ammonia n i t r o g e n , s o l u b l e phosphate, organic n i t r o g e n , potassium, s u l f a t e and v a r i o u s t r a c e elements. Ramaswamy (1969), concluded i n h i s i n v e s t i g a t i o n that the maximum gas p r o d u c t i o n o c c u r r e d i n r e f u s e where N, P and K were 1 .86, 0.31,. 0.23 percent r e s p e c t i v e l y . The N value i s c l o s e to the value of 1.70 % r e p o r t e d by.Alexander (1931) f o r maximum decomposition of organic m a t e r i a l i n s o i l s . A common measure used to e x p l a i n n u t r i e n t a v a i l a b i l i t y , i s the C:N r a t i o of the r e f u s e . Using data from anaerobic d i g e s t o r s , Sanders and Bloodgood (1965) found C:N r a t i o s f o r optimal methane pr o d u c t i o n of around 16:1. However, from data presented i n l a n d f i l l s t u d i e s , t h i s C:N r a t i o f o r optimal methane pro d u c t i o n i s much h i g h e r . One reason l a n d f i l l b a c t e r i a might t o l e r a t e t h i s higher r a t i o c o u l d stem from g e n e t i c a d a p t a t i o n . 14 Dobson (1964), found v a r i a t i o n s of C:N from 34:1 to 104:1 i n samples from the Fairmont, West V i r g i n i a l a n d f i l l (Thompson, 1969). Clement (1981) concludes that a commonly found r a t i o of COD:N:P of 1 0.0:0.44:0.08 f o r optimal gas pr o d u c t i o n i s not s a t i s f i e d i n l a n d f i l l s f o r s o l u b l e P and concludes that lower r a t e s of degradation w i l l probably occur. In c o n t a s t , Rees (1980) demonstrates through a mass-balance approach that N and P are present i n access and do not l i m i t the growth of l a n d f i l l microbes, even.with C:N r a t i o s i n excess of 50:1. Rees (1980) concludes that i f an N or P l i m i t a t i o n e x i s t s , there would be near zero c o n c e n t r a t i o n s of ammonia and P i n l a n d f i l l l e a c h a t e , which i s not common i n most l a n d f i l l l e a c h a t e s . Even though s u l f a t e has been demonstrated to be an e s s e n t i a l element, i f present i n excess amounts, i t can have an i n h i b i t o r y e f f e c t on methane p r o d u c t i o n . T h i s i s due t o ; one, s u l f a t e reducers outcompeting methanogens f o r H 2 gas; two, pro d u c t i o n of s u l f i d e s which can cause t o x i c i t y to methanogens (Jones, 1983 and Rees, 1980). While they can be t o x i c to methanogens, s u l f i d e s can a l s o have a p o s i t i v e e f f e c t by p r e c i p i t a t i n g out c e r t a i n t o x i c metals. High s a l t c o n c e n t r a t i o n s have been r e p o r t e d to i n h i b i t methane p r o d u c t i o n , such as the a d d i t i o n of 2000 mg/L of cal c i u m ions (Crawford and Smith, 1985). F a i l u r e of anaerobic d i g e s t o r s have been shown to occur with very high amounts 2000 mg/L of ammonia-nitrogen (McCarty, 1966). The r o l e that hazardous wastes p l a y s as p o s s i b l e i n h i b i t o r y 15 or n u t r i e n t sources i s unclear i n c o - d i s p o s a l l a n d f i l l s and i s an area that needs to be s t u d i e d . Ways to i n c r e a s e l a n d f i l l n u t r i e n t a v a i l a b i l i t y i n c l u d e a d d i t i o n of sewage or s e p t i c sludge, anaerobic d i g e s t e r supernatant, animal and a g r i c u l t u r a l wastes, and l a s t l y , l eachate r e c i r c u l a t i o n (Schumacher, 1983). 2.1.3.3. REFUSE EMPLACEMENT Method of c e l l c o n s t r u c t i o n d u r i n g l a n d f i l l i n g c o u l d have a major impact on gas and l e a c h a t e p r o d u c t i o n . The amount of precompaction from l a n d f i l l equipment ( i . e . b u l l d o z e r s , compactors) w i l l have a d r a s t i c e f f e c t of emplaced refuse d e n s i t y . U s u a l l y , l a n d f i l l o p e r a t o r s attempt to achieve a 3 3 emplacement d e n s i t y of 590 kg/m (1000 l b s / y d ) (Tchobanaglous, 1977). The g r e a t e r the d e n s i t y by p r e c o n s o l i d a t i o n , the g r e a t e r the t o t a l mass per u n i t volume w i l l be, which should enhance t o t a l gas y i e l d s (Schumacher, 1983). However, t h i s i n c r e a s e d d e n s i t y c o u l d hamper moisture and n u t r i e n t t r a n s p o r t to a c t i v e b i o l o g i c a l areas. T h i s has an e f f e c t of producing gas at lower r a t e s over l a r g e r p e r i o d s (Crawford and Smith, 1985). 2.1.3.4. REFUSE PARTICLE SIZE A r e d u c t i o n i n p a r t i c l e s i z e w i l l expose a g r e a t e r s u r f a c e area f o r m i c r o b i a l d e g r a d a t i o n . The shredding of r e f u s e c r e a t e s a pseudo-homogeneous mass of r e f u s e that a l t e r s i t s d e n s i t y as w e l l . Shredding w i l l a l s o i n c r e a s e m i c r o b i a l a c t i v i t y , and mass t r a n s f e r of n u t r i e n t s . DeWalle and Chian (1979) showed that d e c r e a s i n g the mean diameter of s o l i d waste from 250 mm to 25 mm 16 i n c r e a s e d the gas p r o d u c t i o n r a t e (mainly CO^) from 0.73 m /tonnes-yr to 4.75 m /tonnes-yr (Rees, 1980). G r i n d i n g can a l s o introduce a l o t of trapped a i r i n t o the system. The decrease i n diameter a l s o i n c r e a s e s the s t r e n g t h of l e a c h a t e by f i r s t , i n c r e a s i n g the amount of leached organic carbon d u r i n g the f i r s t year and secondly, extending t h i s amount of l e a c h i n g f o r a longer p e r i o d of time (Raveh and Avnimelech, 1979). 2.1.3.5. HYDROGEOLOGY OF LANDFILL AREA The e f f e c t s of an encroaching water t a b l e w i t h i n l a n d f i l l s can i n h i b i t gas p r o d u c t i o n by washing out v i a b l e methanogens or d i l u t i n g the s o l u b l e s u b s t r a t e a v a i l a b l e to methanogens. Encroaching water t a b l e s have a l s o been observed to have a s t i m u l a t o r y e f f e c t on unsaturated zone gas p r o d u c t i o n because of added moisture (Hughes, e t . a l . , 1971). 2.1.3.6. LANDFILL AGE I t i s g e n e r a l l y thought that once the l a n d f i l l reaches a c e r t a i n age, decomposition of e a s i l y degradable s u b s t r a t e d i s a p p e a r s , l e a v i n g only s l i g h t l y degradable humic and f u l v i c a c i d s , s o l u b l e s a l t s and r e f r a c t o r y compounds. T h i s \" i n a c t i v a t i o n age\" s i g n a l s a l a r g e drop i n methane p r o d u c t i o n . The \" i n a c t i v a t i o n age\" depends on r e f u s e depth, c l i m a t e , and r e f u s e composition. 2.1.3.7. GAS RECOVERY SYSTEM If a l a n d f i l l i s equipped with gas e x t r a c t i o n w e l l s ( d i s c u s s e d i n more d e t a i l l a t e r ) , the p o t e n t i a l f o r lower CH 4 p r o d u c t i o n i s c e r t a i n when 0 9 i s i n t r o d u c e d i n t o the l a n d f i l l 1 7 through a i r i n t r u s i o n . A l s o , can s t i m u l a t e a e r o b i c a c t i v i t y i n the upper l i f t s , c a u s ing a c c e l e r a t e d decomposition and d i f f e r e n t i a l l a n d f i l l s e t t l e m e n t . A proper l a n d f i l l cover coupled with an e f f i c i e n t w e l l c o l l e c t i o n system should decrease the p r o b a b i l i t y of a i r i n t r u s i o n . 2.1.3.8. OXIDATION-REDUCTION POTENTIAL Both Clement (1981) and Farquhar and Rovers (1973) mention that f o r e f f i c i e n t methane generation the ORP (Eh) must be l e s s than -200 mV. Chian e t . a l . (1985) mentions that the h i g h e s t c o n c e n t r a t i o n of methane gas i n t h e i r l y s i m e t e r s o c c u r r e d when the ORP dropped below -200 mV. Zehnder (1978) s t a t e s an even, lower ORP value of -330 mV f o r i n i t i a t i o n of methanogen growth. Not many s t u d i e s have attempted to measure the e f f e c t s of changing ORP i n l a n d f i l l s . T h i s i s mainly due to equipment f a i l u r e or l a r g e a n a l y t i c a l u n c e r t a i n t i e s w i t h i n the c o l l e c t e d , data. Farquhar and Rovers (1973) experienced equipment d i f f i c u l t i e s which r e s u l t e d i n no ORP measurements made at t h e i r O n t a r i o l a n d f i l l study s i t e . A l s o , Zehnder (1978) mentions that i t i s almost impossible to concur an e f f e c t i v e redox p o t e n t i a l i n a complex s o l u t i o n l i k e d i g e s t o r sludge (or l a n d f i l l l e a c h a t e ) , because s e v e r a l d i f f e r e n t uncoupled redox l e v e l s f r e q u e n t l y occur in the same environment. L a s t l y , s t u d i e s show that an i n c r e a s e i n Eh decreases methane p r o d u c t i o n . T h i s i n c r e a s e i n ORP c o u l d be due to encroachment from an o x i d i z i n g groundwater source or more l i k e l y , from i n f i l t r a t i n g r a i n water. 18 2.1.3.9. MOISTURE CONTENT When raw ref u s e i s p l a c e d i n the l a n d f i l l , i t has an inherent moisture content that w i l l a i d i n the i n i t i a l decomposition p r o c e s s . T h i s moisture content i s around 25 % (wet wt.) and w i l l be gr e a t e r with l a r g e r waste f r a c t i o n s of p u t r e s c i b l e s (Emcon Assoc., 1980). M a n d e v i l l e (1979) adds that without a minimum moisture content of 25 % wet wt., the anaerobic phase i s v i r t u a l l y non-existent or occurs at very slow r a t e s (Clement, 1981). Concurring with t h i s was the study of Merz and Stone (1969), who found t h a t , r e f u s e p l a c e d at a moisture content ranging from 30 to 40 %. wet wt. developed an i n i t i a l C0 2 bloom a f t e r which gas pro d u c t i o n ceased u n t i l a d d i t i o n a l moisture was added.' Dobson (1964) rep o r t e d that the maximum decompostion r a t e i n re f u s e took p l a c e at approximately 56 % moisture (wet wt.) (Thompson, 1969). Both Ramaswamy (1970) and Songonunga (1970) got higher values of 60 to 80 % moisture content f o r maximum decomposition. These values agree with Alexander (1961), who rep o r t e d that the maximum r a t e of decomposition of organic matter in s o i l s l i e s i n the range of 40 to 80 %. Many r e s e a r c h e r s c l a i m moisture content, i s the most important parameter f o r o p t i m i z i n g gas p r o d u c t i o n . However, t h i s i s not always the case when e x c e s s i v e i n f i l t r a t i o n o c c u r s . Rovers and Farquhar (1972) n o t i c e d CH 4 c o n c e n t r a t i o n decrease from 19 to 4 % when l a r g e volumes of water i n f i l t r a t e d t h e i r f i e l d t e s t c e l l s a f t e r snowmelt. They observed i n c r e a s e s i n COD, 19 BOD and TDS while observing decreases in r e f u s e temp., a l k a l i n i t y and pH. E x c e s s i v e i n f i l t r a t i o n can a l s o wash out v i a b l e ; b a c t e r i a l c e l l s , i n c r e a s e the ORP (Eh), and s o l u b i l i z e i n h i b i t o r y metals and s a l t s . . Techniques to i n c r e a s e moisture input i n t o l a n d f i l l s i n c l u d e the f o l l o w i n g : r e c i r c u l a t i o n of l e a c h a t e , a d d i t i o n of waste l i q u i d s (sewage sludge, chemical s l u d g e ) , i n c r e a s i n g the p e r m e a b i l i t y of the cover, or c o n s t r u c t i o n on the l a n d f i l l s u r f a c e of runoff c a t c h b a s i n s . Ways to decrease moisture input, i n c l u d e c o n s t r u c t i n g a low p e r m e a b i l i t y cover, or design of a l a n d f i l l t h a t maximizes r u n o f f . 2.1.3.10. TEMPERATURE Most l a b o r a t o r y s t u d i e s have shown that the optimal temperature for anaerobic decomposition and methane p r o d u c t i o n i s around 30 - 37°C (Dobson, 1964, Ramaswamy, 1970 , Kotze e t . a l . 1969). At the Aveley, U.K. i a n d f i l l , temperatures of 43°C appear to be very f a v o r a b l e f o r gas p r o d u c t i o n (Rees, 1980). During summer c o n d i t i o n s t h i s temperature f i r s t appears at 3 m below the s u r f a c e and extends through the water at 7.5 m deep (Jones e t . a l . , 1983). Hartz (1982) found a s i m i l a r temperature of 41°C f o r optimal CH^ production i n l a b o r a t o r y heated samples of r e f u s e . Most l a n d f i l l s do not approach the 30 to 35°C temperature on an annual b a s i s . Robinson and Lucas (1985) n o t i c e d a v a r i a t i o n i n temp, from 18 to 35°C in b u r i e d r e f u s e 20 meters deep. Farquahar and Rovers (1973) found the average annual temperature at a r e f u s e depth of 1.25 m to be 12°C with 20 seasonal f l u c t u a t i o n s from 2 to 21°C. An e x c e l l e n t example of how r e f u s e depth and a i r temperature a f f e c t r e f u s e temperature i s found i n the study of shallow t e s t c e l l s c o n s t r u c t e d i n Sonoma County, CA ( L e c k i e , Pacey and H a l y a d a k i s , 1979). T h i s temperature p r o f i l e i n d i c a t e s a high i n i t i a l temperature (aerobic decomp.) followed by lower seasonal v a r i a t i o n s i n temperature that m i r r o r the v a r i a t i o n i n ambient a i r temperature. A comparison of temperature changes with percent methane was u n f o r t u n a t e l y not done i n t h i s study. McBean and Farquhar (1979) d i d compare v a r i a t i o n s i n percent CH 4 with v a r i a t i o n s of both temp, and p r e c i p i t a t i o n through l i n e a r r e g r e s s i o n . However, t h e i r attempt to c o r r e l a t e these parameters were i n c o n c l u s i v e . One p o s s i b l e reason behind the n o n - c o r r e l a t i o n of % CH 4 and l a n d f i l l temp, c o u l d stem from t h e i r (the methanogens) immediate a d a p t a t i o n to lower seasonal temperatures. One disadvantage f o r c o l d - c l i m a t e l a n d f i l l s (such as O n t a r i o l a n d f i l l s ) i s the impedence of necessary moisture flow caused by seasonal f r e e z i n g of the l a n d f i l l s u r f a c e . T h i s moisture flow i s needed f o r maximum gas p r o d u c t i o n i n l a n d f i l l s . that have not reached f i e l d c a p a c i t y . 2.1.3.11 ALKALINITY AND pH Optimal pH values found i n anaerobic d i g e s t i o n range from around 6.4 to 7.4 with d i g e s t o r performance c o l l a p s i n g at pH below 6.0 (Kotze e t . a l . , 1969). Rhyne and James (1978) conclude that methane p r o d u c t i o n ceases i n a l a n d f i l l when the average pH 21 drops below 6.2 (Schumacher, 1983). However, because of microenvironments and b a c t e r i a l a d a p t a b i l i t y , methane pr o d u c t i o n can occur at pH's l e s s than 6.0. A f t e r r e f u s e emplacement, there g e n e r a l l y i s a gradual i n c r e a s e i n pH to an optimal l i m i t . O r i g i n a l l y , the pH c o u l d be as low as 5.0 due to p r o d u c t i o n of f a t t y a c i d s and C0 2. As more s u b s t r a t e i s m i n e r a l i z e d and COj i s c o v e r t e d to HCO^-, the b u f f e r i n g c a p a c i t y to r e s i s t changes i n pH i s e s t a b l i s h e d . As the a l k a l i n i t y i n c r e a s e s , so does the pH to a p o i n t where methanogens can produce CH^. The i n f l u x of methanogenic a c t i v i t y w i l l consume more organic a c i d s while r a i s i n g the pH even f u r t h e r . T h i s r e l a t i o n s h i p between methane formers and v o l a t i l e f a t t y a c i d p r o d u c t i o n reaches a pseudo-steady s t a t e i n mature l a n d f i l l s (Stage I V ) . For optimum methane gas p r o d u c t i o n the b i c a r b o n a t e a l k a l i n i t y should be g r e a t e r than 2000 mg/L as CaC0 3 (Kotze e t . a l . , 1969). Zehnder (1978) b e l i e v e s that the carbonate b u f f e r i n g system i s the only important system c o n t r o l l i n g pH f o r methane p r o d u c t i o n . However, a few other r e s e a r c h e r s b e l i e v e o t h e r w i s e . (DeWalle, 1980 and P f e f f e r , 1974). DeWalle concludes that ammonia can act as a pH b u f f e r , e s p e c i a l l y i n l a n d f i l l s where low values of TIC ( T o t a l Inorganic Carbon) ( l e s s than 50 mg/L) can e x i s t . Ammonia c o u n t e r a c t s t h i s drop i n pH by consumption of H + i n the below r e a c t i o n : . H + + Ac\" + NH 3 = NH4+ + Ac-P f e f f e r b e l i e v e s that high c o n c e n t r a t i o n s of c e r t a i n organic 22 a c i d s and a c i d s a l t s can c o n t r i b u t e to the t o t a l system a l k a l i n i t y . P f e f f e r e x p l a i n s t h i s by using McCarty's (1964) equation f o r t o t a l a l k a l i n i t y i n d i g e s t o r s . T h i s equation i s shown below: TA = BA + (0.85) * 0.833(TVA) Where TA = T o t a l Alk. (mg/L as CaCO,) BA = T o t a l Bicarbonate Alk. (mg/L as CaCCO TVA = T o t a l V o l a t i l e Acids (mg/L as A c e t i c Acid) 0.833 i s a conversion f a c t o r to mg/L as CaCO, 0.85 accounts for f a c t that only 85 % of v o l a t i l e a c i d a l k a l i n i t y i s measured by t i t r a t i o n to pH 4. Note: This equation assumes no other b u f f e r i n g systems e x i s t . In summary, pH values found i n s a n i t a r y l a n d f i l l s may be i n f l u e n c e d by i n d u s t r i a l waste d i s c h a r g e s , a l k a l i n i t y , r a i n water i n f i l t r a t i o n , or the r e l a t i v e p r o d u c t i o n of organic a c i d s and methane (Boyle, 1976). Some of the eleven f a c t o r s c o n t r o l l i n g gas production and t h e i r i n t e r r e l a t i o n s h i p s are summarized in Figure 2.3. FIGURE 2.3 - Summary of F a c t o r s A f f e c t i n g Gas Production (Figure modified from Farquhar and Rovers, 1973) 23 2.2. REVIEW OF FIELD STUDIES In c o n t r a s t to numerous l a b or l y s i m e t e r - s c a l e s t u d i e s , on l e a c h a t e and gas p r o d u c t i o n , there have been much fewer s t u d i e s attempted i n a f u l l - s c a l e l a n d f i l l s . Some of these f i e l d p r o j e c t s are worth mentioning s i n c e they i n v o l v e s i m i l a r f i e l d techniques to t h i s study. The p r o j e c t s . a r e l i s t e d below i n c h r o n o l o g i c a l order. To t h i s author's knowledge, the e a r l i e s t such study was undertaken by the New York C i t y Department of S a n i t a t i o n around the mid-1930•'s.•' T h e i r main goal was to determine how f a s t refuse decomposed, and what were the microorganisms that mediate that p r o c e s s . They o r i g i n a l l y performed a c o m p o s i t i o n a l study on f r e s h r e f u s e , then l a t e r sampled decomposed re f u s e f o r , microorganisms, organic n i t r o g e n , pH, percent moisture and temperature over a 48 month p e r i o d . Gas samples were a l s o taken. (See Carpenter, 1940 and E l i a s s e n , 1942). In the e a r l y to' mid-1'960' s an i n - s i t u i n v e s t i g a t i o n of movements of gas from decomposing refuse was undertaken i n Los Angeles, CA. T h i s p r o j e c t was headed by E n g i n e e r i n g - S c i e n c e , Inc. and concentrated mostly on the Azusa L a n d f i l l . The p r o j e c t f i n i s h e d i n 1967. The study concentrated mainly on e s t i m a t i n g upward and downward f l u x e s of C O 2 and CH^ gases in the t e s t f i l l . Gas b a r r i e r m a t e r i a l s were t e s t e d i n the l a b f o r the purpose of a t t e n u a t i n g the downward f l u x of C O 2 i n t o the groundwater system. L a t e r s t u d i e s were done on t e s t f i l l s at the Palos Verdes and Calabasas l a n d f i l l s , again l o c a t e d i n L.A. County (See 24. E n g i n e e r i n g Science, Inc., 1967). In 1970, Waterloo U n i v e r s i t y undertook a study to i d e n t i f y the parameters that a f f e c t the p r o d u c t i o n of l a n d f i l l gas and l e a c h a t e . Three c e l l s of 1.2 m i n diameter and 2.3 m deep were pla c e d i n the ground at a l o c a l O n t a r i o l a n d f i l l . Gas p r o d u c t i o n was found to be slow d u r i n g p e r i o d s of no i n f i l t r a t i o n and impeded d u r i n g s p r i n g snowmelt periods.. As expected, l e a c h a t e generation was g r e a t e s t d u r i n g t h i s s p r i n g thaw p e r i o d . (See Farquahar and Rovers, 1973 and Rovers and Farquhar, 1973). In 1972, a s i m i l a r study to the above was i n i t i a t e d i n a Sonoma County, CA. l a n d f i l l . D i f f e r e n t moisture a p p l i c a t i o n s and c e l l c o n s t r u c t i o n were used i n the f i v e separate l a r g e - s c a l e t e s t c e l l s . One of f i v e c e l l s had l e a c h a t e .recycle while another had a p p l i c a t i o n of s e p t i c tank pumpings. V a r i a b l e s monitored over a three year p e r i o d i n c l u d e average c o n s o l i d a t i o n , thermal responses, and l e a c h a t e and gas p r o d u c t i o n v a r i a b i l i t y (See L e c k i e et a l . , 1979). Around 1977, a group of E n g l i s h r e s e a r c h e r s began a thorough study of the Aveley (Essex) l a n d f i l l i n the U.K.. T h i s p r o j e c t was attempting to determine what parameters a f f e c t l a n d f i l l m i c r o b i a l a c t i v i t y (Rees, 1980). They developed a technique of e s t i m a t i n g r e l a t i v e m i c r o b i a l a c t i v i t y by enzyme a c t i v i t y measurements taken w i t h i n the l a n d f i l l . T h e i r r e s u l t s i n d i c a t e a c o r r e l a t i o n of higher methane gas p r o d u c t i o n i n areas of g r e a t e r enzyme a c t i v i t i e s at depth (Jones et a l . , 1983 and Grainger et a l . , 1984). 25 T e c h n i c a l U n i v e r s i t y of Braunschweig, W. Germany i n i t i a t e d a program i n e a r l y 1980 to study the e f f e c t s that l a n d f i l l o p e r a t i o n has on gas and leachate p r o d u c t i o n at the L i n g r e n S a n i t a r y l a n d f i l l (See Stegmann and S p e n d l i n , 1985). Another E n g l i s h r e s e a r c h group headed by Robinson (1985) began a study i n 1982 at the Stangate East l a n d f i l l i n Kent, England. The main goal of t h i s on-going study i s to monitor ( i n -s i t u ) the a t t e n u a t i o n of l a n d f i l l l e a c h a t e i n the unsaturated zone. Before and d u r i n g r e f u s e placement, over 100 instruments have been i n s t a l l e d to measure thermal responses, gas c o n c e n t r a t i o n , and l e a c h a t e c o n c e n t r a t i o n and s a l i n i t y . To the author's knowledge, t h i s i s the most e x t e n s i v e i n - s i t u l a n d f i l l study ever undertaken. The l a s t l a n d f i l l study worth mentioning d e a l s with the BKK c o - d i s p o s a l l a n d f i l l i n West Covina, CA.. T h i s l a n d f i l l not only r e c e i v e d MSW but a l s o 2 b i l l i o n U.S. g a l l o n s of l i q u i d hazardous waste. Numerous e a r l i e r s t u d i e s have co n c e n t r a t e d on determining l a n d f i l l s u r f a c e emissions of hazardous v o l a t i l e s ( C a l i f o r n i a Dept. of Health S e r v i c e s , 1983 and Baker and McKay, 1985), but a recent study (Stephens e t a l . , 1986) looked at the p a r t i t i o n i n g of four hazardous v o l a t i l e s between the l e a c h a t e and gas stream. 2.3. OFFSITE GAS MIGRATION L a n d f i l l gas can migrate from l a n d f i l l s by two mechanisms: con v e c t i o n due to pressure g r a d i e n t , and d i f f u s i o n due to a c o n c e n t r a t i o n g r a d i e n t (Mohsen, 1980). The d i f f u s i v e flow component c o n s i s t s of Knudseri flow, molecular flow and s u r f a c e 26 flow (EPS, 1977). Because of l a n d f i l l gas p r o d u c t i o n , p o s i t i v e i n t e r n a l pressure heads of 2.5 to 5.0 cm of water can c r e a t e a pressure g r a d i e n t which causes the gas to flow c o n v e c t i v e l y from higher to lower pressure (Crawford and Smith, 1985). V e r t i c a l m i g r a t i o n of gas through the l a n d f i l l cover i s mainly c o n t r o l l e d by d i f f u s i o n . F a c t o r s a f f e c t i n g d i f f u s i o n through l a n d f i l l c overs are summarized i n Table 2.4. Attempts to model the emissions of l a n d f i l l gas through covered l a n d f i l l s ( F i n d i k a k i s and L e c k i e , 1979; Farmer, 1980; Shen, 1981; Thibodeaux et a l . , 1981) due to d i f f u s i o n and c o n v e c t i o n are d i s c u s s e d in:more d e t a i l l a t e r i n t h i s t h e s i s . 27 TABLE 2.4 - F a c t o r s A f f e c t i n g D i f f u s i o n Through a L a n d f i l l Cover (Table m o d i f i e d from Baker and MacKay, 1985) FACTOR S o i l p o r o s i t y Atmospheric pressure f l u c t u a t i o n s Temperature g r a d i e n t between l a n d f i l l bottom bottom and s u r f a c e Temperature of cover EFFECT Wind speed Anaerobic Decomposition Chemical r e a c t i o n s Thickness of s o i l l a n d f i l l cover I n f i l t r a t i o n of s u r f a c e water and r e s u l t a n t s o i l moisture content. High p o r o s i t y allows more d i f f u s i o n and emission. P o r o s i t y i s the c o n t r o l l i n g parameter i n the emission of vapors. Pumping a c t i o n from pressure f l u c -t u a t i o n s enhance the measured d i f f u s i o n r a t e of benzene through a s o i l l a y e r by 1 3 % . Large g r a d i e n t s between a warm l a n d f i l l i n t e r i o r and a c o o l s u r f a c e enhance t h e r m a l l y - i n d u c e d d i f f u s i o n Warm gas can form condensate l e a v i n g the vapor absorbed i n the cover, d e c r e a s i n g the e f f e c t i v e d i f f u s i o n r a t e Increased wind at the s u r f a c e enhances the \"wick e f f e c t , \" speeding d i f f u s i o n . T h i s e l e v a t e s i n t e r n a l l a n d f i l l temperature and produces gases, p r i m a r i l y methane, which a c c e l e r a t e . d i f f u s i o n . Exothermic r e a c t i o n s thermal d i f f u s i o n . Increased t h i c k n e s s d i f f u s i o n time. can i n c r e a s e i n c r e a s e s Methane gas p r o d u c t i o n i s enhanced moisture input hence, a c c e l e r a t i n g d i f f u s i o n . Rapid i n f i l t r a t i o n f i l l s s o i l pores,•slowing d i f f u s i o n , 28 2.4. GAS COLLECTION SYSTEMS G e n e r a l l y , gas c o l l e c t i o n systems are used f o r c o n t r o l , of odors, o f f s i t e m i g r a t i o n of l a n d f i l l gas, and more imp o r t a n t l y , f o r f u r t h e r u t i l i z a t i o n of l a n d f i l l gas. They are important f o r t h i s study because the c o l l e c t i o n w e l l s are sampled f o r gas and l e a c h a t e . Gandolla et a l . (1982) d i v i d e s a l a n d f i l l gas recovery and u t i l i z a t i o n system i n t o s i x p o s s i b l e s t e p s . These steps are: c o l l e c t i o n , pretreatment, storage, combustion, energy storage and energy consumption. T h i s author will', mention only the f i r s t two i n d e t a i l . . 2.4.1. COLLECTION The c o l l e c t i o n step i s u s u a l l y taken care of by c o l l e c t i o n \" w e l l s but there are some a l t e r n a t i v e c o l l e c t i o n methods worth mentioning. One method i s through ground probes that are d r i v e n i n t o the l a n d f i l l and p l a c e d on a subsequent vacuum. At the C r o g l i o l a n d f i l l i n S w i t z e r l a n d , s t e e l - t i p p e d , 5 cm diameter probes were d r i v e n 5 to 10 meters i n t o the r e f u s e and 40.to 60 m/day of methane was e x t r a c t e d i n 2 months time from 10. probes i n a 1000 sq. meter area (Gandolla et a l . , 1982). T h i s recovery system i s g r e a t l y a f f e c t e d by a i r i n t r u s i o n and c l o g g i n g , but has the advantages of a low i n s t a l l a t i o n c o s t and immmediate i n s t a l l m e n t a f t e r l a n d f i l l completion (Gandolla et a l . , 1982). Another gas c o l l e c t i o n method i s through coarse permeable c o r r i d o r s of g r a v e l (3.5 to 7.5 cm minus) that can be used i n c o n f i g u r a t i o n s of b l a n k e t s , trenches, s l a n t e d d r a i n s and mounds 29 (Schumacher, 1983). In every case, a p e r f o r a t e d pipe system must be used to t r a n s p o r t the gas. Most of these systems must be c o n s t r u c t e d d u r i n g the f i l l i n g phase of the l a n d f i l l and have water d r a i n s to decrease the p o t e n t i a l f o r seepage b u i l d - u p . T h i s system i s r e l a t i v e l y inexpensive but has problems with a i r i n t r u s i o n and seepage b u i l d - u p . The p r e f e r r e d and most common c o l l e c t i o n system i s by cased e x t r a c t i o n w e l l s . To optimize gas recovery, e x t r a c t i o n w e l l depth should equal 3/4 of the depth of waste (Shen, 1981). The we l l s can be d r i l l e d by a number of techniques such as a t e l e s c o p i c s p i n d l e , c a b l e t o o l r i g , down hole hammer, r o t a r y d r i l l , or with a hollow bore auger ( G i u l i a n i , 1980). The most e f f i c i e n t and common method f o r d r i l l i n g i n r e f u s e l e s s than 25 meters i n depth, i s the truck mounted continuous f l i g h t hollow bore auger. D r i l l i n g problems encountered with hollow bore augers i n c l u d e : borehole c a v e - i n s when d r i l l i n g i n p o o r l y compacted r e f u s e , and slow r a t e s of p e n e t r a t i o n when d r i l l i n g through houshold or c o n s t r u c t i o n d e b r i s (Emcon Assoc., 1980). A core b a r r e l b i t i s o f t e n used f o r d r i l l i n g i n i n t e r v a l s c o n t a i n i n g any c o n s t r u c t i o n d e b r i s (Schumacher, 1983). Borehole diameters range from 15 cm (6 in.) to 90 cm (36. i n . ) . \" Some deeper l a n d f i l l s i n C a l i f o r n i a have i n s t a l l e d 90 meter deep w e l l s that r e q u i r e the use of a crane mounted auger r i g i n s t e a d of a truck mounted r i g ( G i u l i a n i , 1980). Once the boreholes have been completed, the w e l l c a s i n g i s i n s t a l l e d i n the borehole and b a c k f i l l e d with s o i l or g r a v e l . 30 Well c a s i n g i s t y p i c a l l y c o n s t r u c t e d of PVC, even though f i b e r g l a s s , p o l y e t h y l e n e , and s t e e l have a l s o been used (Emcon Assoc., 1980). T y p i c a l w e l l c a s i n g diameters range from 7.5 cm to 15 cm. Well c a s i n g i s t y p i c a l l y s i z e d a c c o r d i n g to the expected gas flow r a t e and the pressure l o s s w i t h i n the w e l l c a s i n g (Schumacher, 1983). The c a s i n g i s t y p i c a l l y t e l e s c o p e d at one p o i n t to c r e a t e a s l i p j o i n t that can accomadate up to 120 cm of l a n d f i l l subsidence before c a s i n g breakage w i l l occur (E.H. Hanson, 1985). C o l l e c t i o n i n t e r v a l s are determined by the l e n g t h of p e r f o r a t i o n i n the w e l l . P e r f o r a t i o n s are u s u a l l y made i n the f i e l d with a d r i l l or saw or c a s i n g can be purchased a l r e a d y p e r f o r a t e d from the manufacturer. The primary requirements f o r p e r f o r a t i o n s a r e : one, that they remain unclogged, two, that they do not r e q u i r e . e x c e s s i v e pressure l o s s e s to draw the gas through them, and three, that they do not unduly weaken the w e l l c a s i n g . (Emcon Assoc., 1980). Above the g r a v e l - f i l l e d c o l l e c t i o n i n t e r v a l , an impermeable concrete or b e n t o n i t e plug i s i n s t a l l e d (60 to 90 cm t h i c k ) to prevent a i r i n t r u s i o n i n t o the c o l l e c t i o n i n t e r v a l . Above t h i s impermeable pl u g , s o i l i s b a c k f i l l e d up to the w e l l head assembly. The w e l l head assembly c o n s i s t s of one, a w e l l head cap equipped with s p e c i a l connections f o r gas sampling and pressure readings, two, a PVC tee to route the gas i n t o the c o l l e c t i o n header, th r e e , a b u t t e r f l y or gate v a l v e that c o n t r o l s gas flow i n t o the header, and four, the c o l l e c t i o n header i t s e l f . The c o l l e c t i o n header i s normally Sch. 40 PVC pipe that takes the 31 e x t r a c t e d gas to a compressor f o r f u r t h e r d i s t r i b u t i o n . Header pipe i s s i z e d much l i k e w e l l c a s i n g with pressure l o s s estimated through a commonly employed pipe f r i c t i o n equation (Emcon Assoc., 1980). . An example of a t y p i c a l e x t r a c t i o n w e l l with w e l l head assembly and c o l l e c t i o n header i s d i s p l a y e d i n F i g u r e 2.4 2.4.2. PRETREATMENT Because vapor s a t u r a t e d l a n d f i l l gas t y p i c a l l y leaves the l a n d f i l l at e l e v a t e d temperatures r e l a t i v e to atmospheric temperatures, condensate w i l l form i n the w e l l head and c o l l e c t i o n headers, e v e n t u a l l y causing o p e r a t i o n a l problems. The simplest technique to, c o n t r o l condensate b u i l d - u p i s through condensate d r a i n s that empty the condensate back i n t o the r e f u s e and away from the c o l l e c t i o n system. A general r u l e i s to i n s t a l l a condensate t r a p f o r every 60 m of c o l l e c t i o n header (Schumacher, 1983). These d r a i n s are connected onto c o l l e c t i o n headers by a simple Tee at the lowest p o i n t s i n the header pipe to maximize drainage. Other ways to e l i m i n a t e condensate from the gas stream i n c l u d e scrubbers, dehydrators, or lowering the, dewpoint of the gas below the ambient, c o l l e c t i o n l i n e temperature (Emcon Assoc., 1980). In upgrading l a n d f i l l gas to p i p e l i n e q u a l i t y , one u s u a l l y has to separate the C0 2 and other i m p u r i t i e s from the methane. A common absorbing s o l v e n t used f o r l a n d f i l l gas i s t r i e t h y l a m i n e , which the C0 2 can be l a t e r recovered by. h e a t i n g up the s o l v e n t (Gandolla et a l . , 1982). Other s o l v e n t treatment systems 32 I CONTROL VALVE a BOX FIGURE 2.3 - Example of a T y p i c a l E x t r a c t i o n W e l l ( R e p r i n t e d w i t h p e r m i s s i o n o f E.H. Hanson and A s s o c i a t e s , 1986.) 33 r e c e n t l y i n use i n c l u d e : d i g l y c o l a m i n e , hot potassium carbonate, propylene carbonate, s e l e x o l , and f l u o r s o l v e n t (Emcon Assoc., 1980). Trace gases can a l s o be removed by dry a b s o r p t i o n systems such as the molecular s i e v e system at Palos Verdes l a n d f i l l (see Bowerman, 1977), and a c t i v a t e d carbon. A l l these systems are expensive and r e q u i r e very l a r g e l a n d f i l l s to be c o s t - e f f e c t i v e . 2.4.3. GAS EXTRACTION PARAMETERS The design and m o d e l l i n g of gas e x t r a c t i o n systems r e q u i r e some parameters to be determined or estimated. Some of these a r e : e x t r a c t i o n w e l l spacing, gas e x t r a c t i o n and p r o d u c t i o n r a t e s , r e f u s e and cover p e r m e a b i l i t y , and l a n d f i l l gas v e l o c i t y . 2.4.3.1. EXTRACTION WELL SPACING Well spacing i s a f u n c t i o n of the r a d i u s of i n f l u e n c e (RI), which i s determined i n the f i e l d d u r i n g an e x t r a c t i o n t e s t . T h i s t e s t c o n s i s t s of i n s t a l l a t i o n of a piezometer or p r e s s u r e probe network around the e x t r a c t i o n w e l l , which l a t e r are monitored f o r gauge pr e s s u r e changes d u r i n g pumping or recovery of the e x t r a c t i o n w e l l . These measured pressure responses are then used to determine the proper r a d i u s of i n f l u e n c e of that e x t r a c t i o n w e l l . The b a s i c assumption i s that no gas i s drawn to the e x t r a c t i o n w e l l from a d i s t a n c e g r e a t e r than that w e l l s RI. Clement (1981) ran i n t o d i f f i c u l t y determining an RI i n h i s study because, of f a u l t y gauge pressure responses, improper pressure probe networking, and h e t e r o g e n i e t i e s w i t h i n the l a n d f i l l study area. 34 The e x t r a c t i o n t e s t s to determine RI u s u a l l y l a s t from s e v e r a l hours to s e v e r a l days f o r each e x t r a c t i o n r a t e . T y p i c a l l y , 2 to 4 e x t r a c t i o n r a t e s are used f o r each w e l l and 2 to 4 w e l l s are t e s t e d per l a n d f i l l (Emcon Assoc., 1980). A f t e r determining RI, the proper w e l l spacing begins with spacing from the l a n d f i l l perimeter inward with o v e r l a p of RI o c c u r r i n g to help c o n t r o l l a n d f i l l gas m i g r a t i o n (Schumacher, 1983). Once the outer w e l l spacing i s confirmed, inner w e l l s are spaced i d e a l l y (given no c o n s t r a i n t s ) at the v e r t i c e s of e q u i l a t e r a l t r i a n g l e s . 2.4.3.2. GAS EXTRACTION AND PRODUCTION RATES To determine the optimal flow r a t e s f o r a given w e l l , one can use the f o l l o w i n g equation: Qw = (K*TT*RI 2*t*D*Gr) / C ( i ) Where Qw = optimal w e l l flow r a t e (L/sec) K = Conversion F a c t o r (1.157E-08 L/day/ml/sec) RI = Radius of i n f l u e n c e (m) t = Refuse t h i c k n e s s (m) D = i n - p l a c e r e f u s e d e n s i t y (kg/m, m3) Gr = methane pr o d u c t i o n r a t e (mL/kg-day) C = F r a c t i o n a l methane c o n c e n t r a t i o n The most d i f f i c u l t parameter to o b t a i n i n equation ( i ) i s the methane gas production r a t e (Gr), that i s dependent on a number of v a r i a b l e s a l r e a d y i n t h a t equation. G e n e r a l l y , Gr i s determined dur i n g the gas e x t r a c t i o n t e s t s that determine RI. In t h i s d e t e r m i n a t i o n , the w e l l flow r a t e i s v a r i e d u n t i l attainment of the maximum e x t r a c t i o n r a t e which minimizes a i r i n t r u s i o n occurs. T h i s e x t r a c t i o n r a t e i s assumed to be equal to the r a t e at which methane i s produced w i t h i n the volume of r e f u s e 35 d e f i n e d by the w e l l s RI. With t h i s i n mind, Gr can be determined by a m o d i f i c a t i o n to eqn. ( i ) below: Gr = Qw / (7T*RI 2*t*D) ( i i ) Where Qw = Optimal w e l l flow r a t e (L/sec) T h i s equation assumes steady s t a t e c o n d i t i o n s and a 100 % gas recovery e f f i c i e n c y , which i s never true s i n c e gas production r a t e s vary over an age of a l a n d f i l l , and not a l l gas produced w i l l be recovered. In f a c t , based on e a r l y experience i n l a n d f i l l gas recovery, Pacey (1976) estimated that only 10 to 50 percent of the t h e o r e t i c a l gas produced w i l l be e x t r a c t e d (Boyle, 1976). One way to i n c r e a s e recovery e f f i c i e n c y would be to i n c r e a s e the d e n s i t y of e x t r a c t i o n w e l l s . In summary, gas p r o d u c t i o n r a t e s c a l c u l a t e d by eqn ( i i ) from f i e l d t e s t s i n e x i s t i n g l a n d f i l l s range from 6.8 to 45.0 mL CH 4/kg of r e f u s e per day (Emcon Assoc., 1980; Clement, 1981;and Schumacher, 1983). Determination of both the gas e x t r a c t i o n and p r o d u c t i o n r a t e s are f u l l of u n c e r t a i n t y and e r r o r . Emcon Assoc. (1980) suggests one way to make.a more accurate determination of gas p r o d u c t i o n r a t e would be through a more thorough t h e o r e t i c a l mass balance (see Emcon Assoc., 1980). On the other hand, t h i s author b e l i e v e s s t o c h a s t i c techniques a v a i l a b l e from the groundwater l i t e r a t u r e may be a b e t t e r way to handle the u n c e r t a i n t y i n l a n d f i l l gas p r o d u c t i o n r a t e s . 2.4.3.3. REFUSE PERMEABILITY The standard c o e f f i c i e n t of p e r m e a b i l i t y (K) depends on both the c h a r a c t e r i s t i c s of the gas and porous media ( r e f u s e , cover or 36 surrounding s o i l s ) . T h i s c o e f f i c i e n t can be expressed as: K = (tf/u)*Ks ( i i i ) Where Y= s p e c i f i c wt. of the gas (kg/m^) 2 M= s p e c i f i c v i s c o s i t y \"\" \"\" (N-sec/m ) Ks = i n t r i n s i c p e r m e a b i l i t y of refuse and/or cap m a t e r i a l (Darcys) I n t r i n s i c p e r m e a b i l i t y depends on upon the f o l l o w i n g p r o p e r t i e s of the porous media: p o r o s i t y , range and d i s t r i b u t i o n of g r a i n s i z e s , and shapes, o r i e n t a t i o n and packing of the g r a i n s . * The c o e f f i c i e n t of p e r m e a b i l i t y (K) determined by equation ( i i i ) i n the Palos Verdes and Sheldon A r l e t a l a n d f i l l s range from 1.04 to 1.55 m/day. Clement (1981) employed f i e l d e x t r a c t i o n data to estimate the K at an O n t a r i o l a n d f i l l by the Cooper-Jacob approximate method for c o n f i n e d unsteady flow. T h i s method i s o f t e n used f o r determining K i n groundwater i n v e s t i g a t i o n s . His s i x K values range from 0.88 to 4.82 m/day, which are w i t h i n the t o l e r a n c e of the values obtained from from eqn. ( i i i ) . 2.4.3.4. GAS VELOCITY Determining the gas v e l o c i t y at which i t e n t e r s the e x t r a c t i o n w e l l i s very important f o r determining whether flow i s laminar or t u r b u l e n t , which i n turn determines i f d a r c i a n flow can be assumed or not. I f non-darcian flow e x i s t s , w e l l e f f i c i e n c y would u n e q u i v o c a l l y decrease. Gas v e l o c i t y i n t o an e x t r a c t i o n w e l l i s determined by the equation ( i v ) that assumes the gas flows normal to an imaginary c y l i n d r i c a l s u r f a c e surrounding the w e l l c a s i n g : Vr = Qw/Area = Qw/(2T*r*h) ( i v ) 37 Where Vr = i n t e r n a l gas v e l o c i t y (m/sec) Qw = w e l l flow r a t e (m /sec) r = r a d i u s of imag. c y l i n d e r (m) h = d i s t a n c e of c o l l e c t i o n i n t e r v a l (m) Once Vr i s determined from ( i v ) , the flow d e s c r i p t i o n can then be found by using the dimensionless parameter, the Reynolds Number (Re). Re i s found below: Re = ($*Vr*D.)/ (v) 3 • Where £ = Density of gas mixture (kg/m ) D = C h a r a c t e r i s t i c dimension of the system (U s u a l l y the mean g r a i n diameter of the porous media) If Re i s l e s s than 1.0 then flow i s g e n e r a l l y p e r c e i v e d to be laminar, and Darcy's flow equation a p p l i e s . As a general r u l e , t h i s seems to occur i n l a n d f i l l s where flow r a t e s are low enough to keep laminar flow. However, Emcon Assoc. (1980) c a u t i o n s that i f l a n d f i l l g r a i n s i z e s reach l a r g e s i z e s p r o p o r t i o n a l to l a r g e g r a v e l , t u r b u l e n t flow may p r e v a i l , d e c r e a s i n g recovery e f f i c i e n c y i n e x t r a c t i o n w e l l s . 2.5. AMMONIA GAS FROM LANDFILLS 2.5.1. PHYSICAL PROPERTIES OF AMMONIA GAS Ammonia i s a c o l o r l e s s gas under standard c o n d i t i o n s , whose pungent odor i s e a s i l y d i s c e r n i b l e above 50 ppm (NRC, 1979). The ammonia molecule has a pyramidal s t r u c t u r e , with the n i t r o g e n atom at the apex and hydrogen atoms at the base. The bond angles between the H-N-H have been observed to be 106°47' (NRC, 1979). Other p h y s i c a l p r o p e r t i e s of ammonia are l i s t e d i n Table 2.4. 38 TABLE 2.4 - P h y s i c a l P r o p e r t i e s of Ammonia Gas PROPERTY VALUE SOURCE molecular weight 17.03 gm/gm-mole API, 1981 m e l t i n g p o i n t -77.70 C degrees API., 1981 b o i l i n g p o i n t -33.35 C degrees API, 1981 c r i t i c a l temp. 132.45 C degrees NRC, 1979 c r i t i c a l p r e s s . 112.30 atmospheres NRC, 1979 d e n s i t y (gas) 0.7714 kg/m API, 1981 heat of vapor. 5,581 cal/mole NRC, 1979 s p e c i f i c heat 8.523 cal/mole-degree NRC, 1979 s o l u b i l i t y * 89.9 gm NH3/100 gm H20 (0 C, 1 atm) 68.4 gm NH3/100 gm H20 (10 C, 1 atm) 51.8 gm NH3/100 gm H20 (20°C, 1 atm) 40.8 gm NH3/100 gm H20 (30°C, 1 atm) 33.8 gm NH3/100 gm H20 (40°C, 1 atm) * A l l s o l u b i l i t y data i s from Freney (1981) 2.5.2. SOURCES AND AMBIENT ATMOSPHERIC LEVELS OF NH3 2.5.2.1. NATURAL SOURCES The NRC (1979) b e l i e v e s that over 99.5 % of atmospheric-ammonia i s produced by n a t u r a l b i o l o g i c a l processes due to decomposition of organic waste m a t e r i a l . T h i s percentage c o n t r a s t s with a Canadian study done by Geadah (1985) that estimates n a t u r a l decomposition emissions account for 71.2 % of the t o t a l atmospheric emission of ammonia. Geadah (1985) l i s t s the n a t u r a l sources of ammonia emission to be: b i o l o g i c a l l i t t e r decomposition, animal waste, v e g e t a t i o n emissions, f o r e s t f i r e s , and human breath. Ammonia r e l e a s e d from s o i l s due to decomposition can be estimated by Dawson's model (Geadah, 1985). Ammonia r e l e a s e d from animal waste i s mainly due to urea h y d r o l y s i s from the enzyme urease. Estimated p r o d u c t i o n of ammonia by c a r n i v o r e s and h e r b i v o r e s i s 186.3 and 16.42 gm of NH • 39 per kg of animal weight per year (Geadah, 1985). T h i s e s t i m a t i o n assumes that 10 % of the generated urea produces v o l a t i l i z e d ammonia. Because of t h i s s u b s t a n t i a l amount, ambient NH^ gas l e v e l s around d a i r y farms have been measured as high as 450 ppb (usual ambient l e v e l around 5 ppb) (NRC, 1979). F o r e s t f i r e s have been estimated to produce 0.15 kg of NH^/tonne of dry wood during combustion (Geadah, 1985). Human breath has been found to emit 11.2 mg NH^/day f o r non-smokers and 16.8 mg NH^/day f o r smokers. Geadah (1985) concludes i n her 1980 study that m i c r o b i a l a c t i v i t y emits a 10-fold g r e a t e r mass of NH^ i n tonnes/annum than the three other n a t u r a l sources combined. 2.5.2.2. ANTHROPOGENIC SOURCES Major anthropogenic sources of NH^ i n c l u d e the f o l l o w i n g l i s t by NRC (1979): 1. Combustion processes i n urban areas, such as domestic h e a t i n g , i n t e r n a l combustion engines, and m u n i c i p a l waste i n c i n e r a t i o n . 2. I n d u s t r i a l sources, such as f e r t i l i z e r p l a n t s , . r e f i n e r i e s , organic chemical process p l a n t s , and s t r i p mining. 3. M i s c e l l a n e o u s sources, such as c a t t l e f e e d l o t s , food p r o c e s s i n g p l a n t s , use of NH^ i n i n d u s t r i a l and household c l e a n i n g , f e r t i l i z e r a p p l i c a t i o n , and sewage treatment p l a n t s . 2.5.2.3 AMBIENT ATMOSPHERIC LEVELS Ambient atmospheric c o n c e n t r a t i o n s of n o n - p a r t i c u l a t e ammonia i n r u r a l u n p o l l u t e d areas has been measured by a number of r e s e a r c h e r s (Junge, 1963, NRC, 1979, Harward e t . a l . , 1982, and K e l l y e t . a l . , 1984). T h e i r r e p o r t e d mean NH--N v a l u e s 40 range from 2.2 to 10.0 ppb. N o n - p a r t i c u l a t e ammonia l e v e l s measured in urban areas are much higher (max. 400 ppb) i n most cases, with marked maximums in the winter, owing to the i n c r e a s e d c o n t r i b u t i o n from combustion sources. 2.5.2.4. ANALYTICAL TECHNIQUES Some of the a n a l y t i c a l techniques employed to measure these low atmospheric l e v e l s of NH^-N are l i s t e d below: 1. Bubbler techniques using a c i d s o l u t i o n s to absorb the NH_, which i s then analyzed by c o l o r i m e t r i c - t i t r i m e t r i c methods. T h i s method was used i n t h i s study on l a n d f i l l gas. 2. Ring oven techniques using impregnated f i l t e r s u b s t r a t e f o r d i r e c t a b s o r p t i o n of ammonia gas. 3. Photoacoustic d e t e c t i o n of desorbed ammonia from a t e f l o n bead sampler (see Harward, 1982). 4. Real time measurement using a c a l i b r a t e d f l u o r e s c e n c e d e r i v a t i z a t i o n technique,. D e t e c t i o n l i m i t i s about 0.3 ppb (see K e l l y e t . a l . , 1984) 5. . Recent developments i n more s e n s i t i v e , r e l i a b l e and more expensive techniques such as F o u r i e r - t r a n s f o r m long-path i n f r a r e d spectroscopy, second d e r i v a t i v e spectroscopy, and the combination of gas chromatography and chemiluminescence (see NRC, 1979). 2.5.3. AMMONIA GENERATION IN LANDFILLS 2.5.3.1. SOURCES The overwhelming m a j o r i t y of ammonia inherent to l a n d f i l l s i s produced from decomposition of p r o t e i n s indigenous to the bulk r e f u s e . Other sources of NH^ c o u l d be due to l a n d f r i l i n g of f e r t i l i z e r products, ammonium s a l t s , animal wastes, sewage or chemical sludge, or from atmospheric i n p u t . N u c l e i c a c i d (RNA and DNA) decomposition i s another minor source of ammonia i n l a n d f i l l s . . 41 T o t a l n i t r o g e n has been rep o r t e d i n bulk a n a l y s i s of r e f u s e to.range from a low of 0.33 % weight ( B e l l , 1963) to a hi g h of 3.0 % i n Raveh and Avnimelech (1979). Most r e s e a r c h e r s (Thompson, 1969, P f e f f e r , 1974, Tchobanagolous, 1977, and Rees, 1980) r e p o r t v a l u e s from 0.5 % to 1.25 % t o t a l n i t r o g e n with 1.7 % r e q u i r e d f o r maximum decompositon of or g a n i c matter (Alexander, 1961). L a n d f i l l s that are d e f i c i e n t i n n i t r o g e n can b e n e f i t by the a d d i t i o n of sewage sludge, as percent n i t r o g e n i n these sludges has been r e p o r t e d to be on the average about 3.1 % (Hobson e t . a l . , 1974). 2.5.3.2. PRODUCTION OF AMMONIA The genera t i o n of ammonia from p r o t e i n s i s a b i o l o g i c a l l y mediated procedure i n v o l v i n g m u l t i p l e steps Of b i o l o g i c a l a c t i v i t y . These steps can b a s i c a l l y be superimposed on the stages of methane pr o d u c t i o n d i s c u s s e d i n 2.1.2.2.. A s i m p l i f i e d r e a c t i o n f o r ammonia genera t i o n would be as f o l l o w s : enzymes P r o t e i n > Amino Acids - — > F a t t y A c i d s + NH_ + C0 9 H 2 O H 2 O - . f ; . In the f i r s t r e a c t i o n , p r o t e i n i s a t t a c k e d b y ' e x t r a c e l l u l a r enzymes known as proteases that hydrolyze the pep t i d e bonds between amino a c i d s . T h i s h y d r o l y s i s r e a c t i o n r e l e a s e s f r e e amino and c a r b o x y l groups that can be f u r t h e r degraded by r e a c t i o n \" 2 . The major group of organisms r e s p o n s i b l e f o r r e a c t i o n 1 are the p r o t e o l y t i c b a c t e r i a . C l o s t r i d i u m s p e c i e s were found to be the most p r e v a l e n t p r o t e o l y t i c b a c t e r i a i n anaerobic d i g e s t o r s t u d i e s performed by S i e b e r t and To e r i a n 42 (1969). S e p a r a t i o n of the amino a c i d s i n t o carbon and n i t r o g e n sources i n r e a c t i o n 2 i s done a number of ways. Four common mechanisms are shown below using the amino a c i d G l y c i n e (CHNH2COOH) as example: 1. H y d r o l y t i c deamination G l y c i n e > RCH=CHCOOH .+ NH^ 2. Reductive deamination G l y c i n e + H 2 —-> Ac e t a t e - + NH4+ 3. D e c a r b o x y l a t i o n ( l e a d i n g t o subs, a l c o h o l fermentation) G l y c i n e > Amine + C0 2 > A l c o h o l + NH 3 4. S t r i c k l a n d Reaction (coupled deamination) 2 G l y c i n e + Alanine + 3 H 20 -—> 3 Ac e t a t e - + 3 NH4+ + HC0 3~ + H+ Some amino a c i d s are r e s i s t e n t while others are h i g h l y s u s c e p t i b l e to decomposition to ammonia.. For example, ammonia i s formed r e a d i l y from a r g i n i n e and tryptophane, while l y s i n e , t hreonine and methionine have a more extended p e r s i s t e n c e i n s o i l t e s t s (Alexander, 1961). Again, C l o s t r i d i a sp. appear to be the most dominant microorganism i n r e a c t i o n 2. Anaerobic c o c c i were a l s o found as a c o n t r i b u t o r to r e a c t i o n 2 i n Songonunga's (1970) work. The S t r i c k l a n d Reaction appears to be the c o n t r o l l i n g mechanism f o r ammonia f o r m a t i o n . At l e a s t 15 sp e c i e s of C l o s t r i d i a can obta i n energy from the S t r i c k l a n d Reaction (Thompson, 1967). Other than r e g u l a t i n g the formation of ammonia in l a n d f i l l s , the S t r i c k l a n d Reaction i s a major c o n t r i b u t o r to 43 v o l a t i l e f a t t y a c i d p r o d u c t i o n i n le a c h a t e , and has been t h e o r i z e d to be a major competitor f o r H 2 needed f o r methane pr o d u c t i o n (Nagase and Matsuo, 1982). The r e a c t i o n a l s o r e l e a s e s H + ions, dropping the pH, which i s not f a v o r a b l e . f o r mechanism (1), h y d r o l y t i c deamination (Songonunga, 1970) . Instead, d e c a r b o x y l a t i o n (2) becomes more p r e v a l e n t at low pH's hence, r e l e a s i n g more a l c o h o l s i n t o s o l u t i o n . 2.5.3.3. AMMONIA SINKS The major sink of newly generated ammonia appears to be due to growth a s s i m i l a t i o n from the b a c t e r i a t hat produce i t i n the f i r s t p l a c e . The m a j o r i t y of b a c t e r i a need NH 4 + and not organic n i t r o g e n (amino a c i d s , amines, e t c . ) f o r a s s i m i l a t i o n i n t o t h e i r protoplasm. In f a c t , ammonia has been proven to be the only n i t r o g e n compound needed f o r growth i n methanogens (Hobson et a l . , 1974). Other than NH^+ a s s i m i l a t e d by c e l l s y n t h e s i s , there are other l e s s common s i n k s of fr e e ammonia. They are l i s t e d i n poi n t form below: 1. C a t i o n exchange of NH^+ onto re f u s e or s o i l c o l l o i d s . 2. Ammonia f i x a t i o n or \"ammohylsis\" by organic compounds such as halogenated aromatics (NRC, 1979) or c a r b o x y l and other a c i d i c o rganic groups that combine with NH3 to form s o l u b l e s a l t s (Freeney e t . a l . , 1981) 3. N i t r i f i c a t i o n c o u l d occur i f fr e e oxygen i s around to be an e l e c t r o n a c c e p t o r . 4. V o l a t i l i z a t i o n of NH^ through l a n d f i l l . 2.5.3.4. LANDFILL AMMONIA BALANCE When decomposition and growth become psuedo-steady s t a t e , the ammonia balance w i t h i n an completely anaerobic l a n d f i l l 44 environment can be presented as f o l l o w s (modified from Waksman, 1931): N decomp. - (N growth + N org. n i t r o g e n + N s i n k s ) = N as NH^-N T h i s balance i n d i c a t e s that as p r o t e i n decomposition r a t e s exceed growth requirements f o r NH4+, ammonia w i l l begin to accumulate as a waste product. T h i s accumulation w i l l e i t h e r be leached, f i x e d , exchanged or v o l a t i l i z e d from the system. A mathematical treatment of these processes has been done by Smith (1982) regarding s o i l microbes. He uses Michaelis-Menton s u b s t r a t e k i n e t i c s to c a l c u l a t e a net s o i l s o l u t i o n NH^-N by s u b t r a c t i n g the ammonia p r o d u c t i o n r a t e (mostly from deamination) from the v a r i o u s NH^-N uptake r a t e s . Refer to page 135 i n Smith (.1982) f o r f u r t h e r d e t a i l . 2.5.4. FACTORS AFFECTING AMMONIA MOVEMENT IN LANDFILLS 2.5.4.1. MASS TRANSFER IN UNSATURATED ZONE In the unsaturated zone of the l a n d f i l l , there are four phases i n which ammonia can occur. The two s o l i d phases are the bulk r e f u s e and the b i o f i l m surrounding the r e f u s e . Surrounding t h i s b i o f i l m i s a l i q u i d l a y e r f o l l o w e d by the gas f i l l e d f r a c t i o n of the refuse pores. A c r o s s - s e c t i o n of these four phases i s presented i n F i g u r e 2.4. The r a t e - l i m i t i n g step i n NH^ t r a n s f e r to the gas phase appears to occur i n the b i o f i l m where the m i c r o b i a l processes inherent i n the b i o f i l m r e g u l a t e f u r t h e r NH^ t r a n s p o r t . I f there i s a net accumulation of NH4+, then NH^+ w i l l move through the b i o f i l m as a f u n c t i o n of i t ' s d i f f u s i o n c o e f f i c i e n t . From 45 NH3 GAS AMINES N H 4 + I n H 20 VAPOR — 150 — -•w um R e l a t i v e c o n c e n t r a t i o n l i n e -•w D' NH3 GAS N H 4 + ORGANIC N NH3 GAS NH 4 + ORGANIC N REFUSE SUBSTRATE c x H y U z N i A B C D . E , F. G , B i o f i l m - r e f u s e i n t e r f a c e B i o f i l m - N H 4 + movement t h r o u g h b i o f i l m depends on d i f f u s i o n and b i o f i l m u p t a k e r a t e . L i q u i d F i l m B u l k L i q u i d L i q u i d F i l m Gas F i l m B u l k Gas Assume l i q u i d i s c o m p l e t e l y mixed and c o n t a i n s b i o f i l m s l o u g h , s o l u b l e s u b s t r a t e and b a c t e r i a f l o e . Assume s t e a d y s t a t e g a i n or l o s s o f NH3-N i n t h i s zone. C o n t a i n s H2O v a p o r , and l a n d f i l l gas components. Assume p a r t c u l a t e mass i s n e g l i g i b l e . FIGURE 2.4 - M i c r o s c o p i c C r o s s - s e c t i on t h r o u g h l a n d f i l l s howing mass t r a n s f e r o f NH3-N i n t o b u l k gas, assu m i n g a b i o f i l m model. 46 s t u d i e s done on mixed and pure b i o f i l m c u l t u r e s , the d i f f u s i o n c o e f f i c i e n t ranges from 1.03E-05 to 1.50E-05 cm /s (Williamson and McCarty, 1976, and Onuma and Omura, 1982). T h i s d i f f u s i o n c o e f f i c i e n t has been seen to vary with v a r y i n g r a t i o s of C:N i n the b i o f i l m (Onuma and Omura, 1982). Other than m i c r o b i a l a s s i m i l a t i o n of NH^-N, ion exchange can be an e f f e c t i v e sink of NH^-N i n b i o f i l m s . Most of the NH^-N w i l l be i n the ammonium i o n i z e d form due to f a i r l y low pH's caused by f a t t y a c i d p roduction ( S t r i c k l a n d R e a c t i o n ) , e s p e c i a l l y where inadequate a l k a l i n i t y e x i s t s . Sloughing of the b i o f i l m r e l e a s i n g NH^-N c o u l d occur due to normal sloughing mechanisms, or due to C O 2 -CH 4 gas bubble formation shearing the b i o f i l m . Mass t r a n s f e r from the b i o f i l m to the bulk l i q u i d i s mostly a f u n c t i o n of the d i f f u s i o n a l r e s i s t a n c e encountered by the l i q u i d t h i n f i l m (part c i n F i g u r e 2.4) The-'liquid t h i n f i l m t h i c k n e s s i s a f u n c t i o n of the Reynolds Number (Re) of the f l u i d , with t h i c k n e s s approaching zero with i n c r e a s i n g values (meaning greater f l u i d turbulence) of Re. The f l u x or mass of NH^-N , t r a n s p o r t e d per u n i t area per u n i t time i s given by (Grady, 1983): • J = Dw/Lw*(Cb - Cw) ( v i i ) 2 Where Dw = l i q u i d f i l m d i f f u s i o n c o e f f . ( cm /sec) ( e s t . at 1.7E-07 from Reddy and P a t r i c k , 1983) Lw - l i q u i d f i l m t h i c k n e s s (cm) Cb = c o n c e n t r a t i o n of NH_-N i n b i o f i l m (mg/L) Cw = c o n c e n t r a t i o n of NH^-N i n bulk l i q u i d (mg/L) Once the NH^-N i s i n the bulk l i q u i d , NH^ t r a n s f e r i n t o the bulk gas depends on i t ' s s o l u b i l i t y , Henry's Law constant (Hx) .47 and mass t r a n s f e r c o e f f i c i e n t (K) of NH 3 > S o l u b i l i t y p l a y s a key part i n how much of the t o t a l NH^-N i n s o l u t i o n i s a c t u a l l y u n i o n i z e d NH^. Th i s f r a c t i o n i s then a v a i l a b l e f o r t r a n s p o r t i n t o the bulk gas. The governing e q u i l i b r i a of NH^ formation i s shown i n the h y d r o l y s i s r e a c t i o n below: NH 3 + H 30+ <====> NH4+ + 0H-Th i s r e a c t i o n i n d i c a t e s that as pH i n c r e a s e s , so w i l l the un i o n i z e d f r a c t i o n of NH^-N i n c r e a s e , l e a v i n g a grea t e r f r a c t i o n for t r a n s f e r i n t o the bulk gas. Other than pH, the un i o n i z e d f r a c t i o n of NH3~N i s a f f e c t e d by changes i n temperature, . pres s u r e , i o n i c s t r e n g t h and s a l i n i t y . . Numerous authors such as T r u s s e l (1972), Skarheim (1973), Thurston e t . a l . (1974), W h i t f i e l d (1974) and Bower and B i d w e l l (1978) have c a l c u l a t e d the v a r i a t i o n of u n i o n i z e d f r a c t i o n of NH3~N due to v a r i a t i o n s i n these parameters. Mass t r a n s f e r of the s o l u b l e NH 3 a c r o s s the water/gas i n t e r f a c e (D-G on F i g u r e 2.4) i s r e g u l a t e d by the d i f f u s i o n a l . r e s i s t e n c e encountered i n both the l i q u i d and gas t h i n f i l m s . The two f i l m d i f f u s i o n model was developed by Lewis and Whitman in 1924. The model assumes that the s o l u t e (NH 3) i s uniformly mixed i n the bulk a i r and gas phases and encounters molecular d i f f u s i o n only i n the t h i n f i l m s (E and F i n F i g u r e 2.4). Steady s t a t e c o n d i t i o n s are assumed as w e l l , so that the mass f l u x e s through each f i l m i s equal (Rathbun and T a i , 1982). With t h i s i n mind, the o v e r a l l r e s i s t a n c e to mass t r a n s f e r i s the sum of the r e s i s t a n c e s i n the l i q u i d and gas f i l m . • 48. Rt = RI + Rg ( v i i i ) Where RI = 1/kl where k l = D l / L l Rg = 1/Hxkg where kg = Dg/Lg . So Rt = 1/Kt Where Kt i s i n meters/day Th e r e f o r e , the o v e r a l l mass t r a n s f e r c o e f f i c i e n t . i s : 1/Kt = 1/kl + 1/Hxkg ( i x ) U s u a l l y t h i s mass t r a n s f e r c o e f f i c i e n t i s determined through l a b o r a t o r y measurements (Rathbun and T a i , 1982, Murphy e t . a l . , 1987, or MacKay and Shiu, 1981). Again, the f i l m t h i c k n e s s e s depend on the Re of the surrounding f l u i d , which can become q u i t e important i n l a n d f i l l environments where t u r b u l e n t methane co n v e c t i o n flow can c r e a t e t h i n gas f i l m s . The value of Henry's Law.constant (Hx) w i l l determine i n most cases whether the r e s i s t a n c e t o mass t r a n s f e r i s i n the l i q u i d , gas or both t h i n f i l m s . S olutes with high Henry's Law constants (>>1.0 atm/mole f r a c t i o n ) , have r e s i s t a n c e mostly i n the l i q u i d f i l m , while small Hx's (<<1.0 atm/mole f r a c t . ) w i l l have mostly gas f i l m r e s i s t a n c e (Thibodeaux, 1979). For Hx's of around 0.5 to 1.5 a t m / m o l e . f r a c t r e s i s t a n c e s may occur, from both t h i n f i l m s . T h i s i s e s p e c i a l l y true f o r a h i g h l y s o l u b l e v o l a t i l e compound l i k e ammonia. Some Hx's f o r common l a n d f i l l gas c o n s t i t u e n t s are l i s t e d below (from Thibodeaux, 1979): 49 COMPOUND Hx (atm/mole f r a c . ) RESISTANCE N 2 86,500.0 c8 57,000.0 H»S 54,500.0 L i q u i d Phase °2 .43,800.0 CH 41 ,000.0 C 0 2 1,640.0 NH 3 0.843 Both Phases P r o p i o n i c A c i d 0.0130 Gas Phase Once•the Kt i s determined, the f l u x (Jg) i n t o the bulk gas phase can be estimated from equation (x) below. To use t h i s equation, one must know or a c q u i r e c o n c e n t r a t i o n s of the bulk gas and l i q u i d phase, and a l s o convert Hx from atm/mole f r a c . to atm-m^/mole. Jg = Kt(Cw - RTCg/Hx) (x) Where R = i s gas constant ( i n atm-m /mole-K degrees) T = Temperature in K Cg = Bulk c o n c e n t r a t i o n i n gas phase (mg/L) Cw = Bulk c o n c e n t r a t i o n i n l i q u i d phase (mg/L) A t y p i c a l Hx f o r NH^ at 25°C c a l c u l a t e d from Stumm • 3 and Morgan (1981) i s 1.73E-05. atm-m /mole. D i f f e r e n t e x p r e s s i o n s f o r Hx w i l l be d i s c u s s e d i n f u r t h e r d e t a i l l a t e r i n t h i s t h e s i s . 2.5.4.2. MASS TRANSFER IN SATURATED ZONE In most cases when l a n d f i l l s have a p e r m e a b i l i t y g r e a t e r than the surrounding s o i l s , mounding of the l o c a l water t a b l e may occur w i t h i n the l a n d f i l l , c r e a t i n g a l a n d f i l l s a t u r a t e d zone. Other than mounding, h e t e r o g e n i e t i e s w i t h i n the l a n d f i l l r e fuse may cause perched zones of l e a c h a t e to develop. T h i s s c e n a r i o c r e a t e s a macroscopic planar f e a t u r e where mass t r a n s f e r of 50 ammonia can occur at the sa t u r a t e d - u n s a t u r a t e d i n t e r f a c e r e g u l a t e d by the same two- f i l m theory a l r e a d y d i s c u s s e d . A macroscopic conceptual model of t h i s mass t r a n s f e r i s presented i n F i g u r e 2.5. Some important e q u i l i b r i a r e a c t i o n s that can a f f e c t the amount of ammonia a v a i l a b l e f o r t r a n s f e r i n t o the gas phase are a l s o presented i n F i g u r e 2.5. These r e a c t i o n s w i l l be d i s c u s s e d i n more d e t a i l l a t e r . 2.5.4.3. FURTHER MOVEMENT IN LANDFILL Once NH3 i s i n the bulk gas, f u r t h e r movement i n the l a n d f i l l would be from d i f f u s i o n or c o n v e c t i o n flow. R e t a r d a t i o n or removal of NH^ from the bulk gas would be from s o r p t i o n onto l a n d f i l l or cover m a t e r i a l , or r e d i s s o l v i n g i n t o the s a t u r a t e d l a n d f i l l gas vapor. 51 UNSATURATED ZONE N 2 + 0 2 C0 2| VOC ' s NH3 + C0 2 A NH3 g H 2S| CH4 + NH3 CAPILLARY ZONE (?) V N H 3 - C 0 2 | a q H 2S «, HS- % S' VOC ' s NH3 | aq C H 4 C0 2 l a q H HCO3- 003' SATURATED ZONE C H 4 C H 4 N H 4 + | a q NH 3 + H 20 % NH4 + + OH\" H 20 H H + + OH -NH4\" SOLID N H 4 + + M a H NH 4M< 1 + a) FIGURE 2.5 - C r o s s - S e c t i o n o f S a t u r a t e d - U n s a t u r a t e d Zone Showing mass - t r a n s f e r and major c h e m i c a l r e a c t i o n s a f f e c t i n g mass t r a n s f e r o f l a n d f i l l g as. '52 CHAPTER 3 3. SITE DESCRIPTION AND HISTORY 3.1 MATSQUI - CLEARBROOK LANDFILL 3.1.1. LOCATION Matsqui - Clear/brook l a n d f i l l i s a 10 ha s i t e l o c a t e d approximately 3 km north of downtown Clearbrook j u s t o f f Tretheway S t r e e t ( F i g u r e s 3.1. & 3.2). The approximate e l e v a t i o n of the s i t e i s 45 m above mean sea l e v e l . 3.1.2. PHYSICAL DESCRIPTION The r e g i o n a l hydrogeology around Clearbrook i s dominated by a g l a c i o f l u v i a l t i l l interbedded w i t h i n f l u v i a l sands and. g r a v e l s . These d e p o s i t s were termed \"Sumas D r i f t \" by H a l s t e a d (1986). These d e p o s i t s can be found i n a neig h b o r i n g g r a v e l p i t op e r a t i o n (See F i g u r e 3.3) where a cut bank 15 meters high shows interbedded sands and g r a v e l s . Some of the coarse bedding even e x h i b i t s i m b r i c a t i o n , a common i n d i c a t i o n these g r a v e l s are of f l u v i a l (channel d e p o s i t i o n ) o r i g i n . L o c a l groundwater l e v e l s appear to be about 12-13 m below the land s u r f a c e i n the winter by d i r e c t i n s p e c t i o n of g r a v e l p i t ponds. The average annual p r e c i p i t a t i o n on the s i t e i s approximately 1400 mm taken from the l o c a l weather s t a t i o n i n nearby Abbotsford. . 3.1.3. HISTORY AND CHARACTERISTICS OF FILL T h i s t r e n c h - f i l l o p e r a t i o n began i n 1974 with l a n d f i l l i n g moving from a west to east d i r e c t i o n at the s i t e . Intermediate or d a i l y cover was a t h i n l a y e r of the trenched sands and g r a v e l s . The l a s t c e l l opened i n 1983 and ended i n e a r l y 1984 53 ( W i l l i e Riemer, p e r s . comm., 1987). The f i l l averages about 12 m i n t h i c k n e s s and c o n s i s t e d mostly of MSW with u n u s u a l l y l a r g e amounts of dead animals that were l a n d f i l l e d i n c e l l s or i n d i v i d u a l p i t s . The dead animals were p r i m a r i l y from the l o c a l p o u l t r y i n d u s t r y . Other types of m a t e r i a l l a n d f i l l e d i n c l u d e : l a r g e volumes of gypsum board, which causes gr e a t e r s u l f i d e formation and r e g u l a r dumpings of sewage sludge ( W i l l i e Riemer, p e r s . comm., 1987). •The f i n a l cover was c o n s t r u c t e d of h i g h l y compacted l o c a l trenched sands and g r a v e l s (same as int e r m e d i a t e cover) with approximate t h i c k n e s s of about 0.70 m. On top of the f i n a l cover a l a y e r of crushed g r a v e l has been i n s t a l l e d , so that the. l a n d f i l l can be used as a par k i n g l o t f o r l o c a l a c t i v i t i e s at the neighboring multi-purpose b u i l d i n g (See F i g u r e 3.3). T o t a l p o r o s i t y of the cover i s estimated to be about 35%. O f f s i t e m i g r a t i o n of le a c h a t e has not been documented; however, steps have been taken to r e g u l a t e the drainage flow a few 100 meters northwest of the s i t e , G r a v e l p i t ponding shows no p h y s i c a l evidence ( c o l o r or smell) of le a c h a t e contamination; hence, the author b e l i e v e s the groundwater.gradient i s i n a north-northwest d i r e c t i o n . Low volume, high s t r e n g t h seepage was n o t i c e d f o r the f i r s t time i n e a r l y A p r i l , 1988 i n the g r a v e l p i t cut bank adjacent to the f i l l a r e a . T h i s discharge seemed to foll o w c o n s i s t e n t l y heavy r a i n s the week b e f o r e . 3.1.4. GAS EXTRACTION SYSTEM Problems with o f f s i t e methane m i g r a t i o n were d e t e c t e d i n FIGURE 3.1 - SITE LOCATION MAP Showing M a j o r Waterways, Roads and M e t r o p o l i t a n A r e a s 55 SCALE •FIGURE 3.2 - LOCATION MAP C l e a r b r o o k - M a t s q u i L a n d f i l l 56 CARETAKER HOUSE u > < a! — ANTIQUE BLDG. • BLOWER HOUSE CD M U L T I -P U R P O S E \" B L D G . BARN LEGEND 0 S a m p l i n g w e l l s Q A i r I n j e c t , w e l l s O E x t r a c t i o n and f u e l w e l l s • 100 SCALE METERS o • • F l F6 F5 F4 F2 F3 F8 • • O • -° -2 O O £ J FIGURE 3.3 - SITE MAP o f C l e a r b r o o k - M a t s q u i L a n d f i l l ( A d a p t e d from E.H. Hanson & A s s o c . , J a n . 1985) 57 1983 before the l a s t f i l l was completed. In November, 1983, \"E.H. Hanson & Assoc. began a design of a gas c o l l e c t i o n and u t i l i z a t i o n system. The s t r u c t u r e s that were i n g r e a t e s t danger of methane e x p l o s i o n s were the multi-purpose b u i l d i n g and storm sewer on Haida Dr i v e (See F i g u r e 3.3). . Methane c o n c e n t r a t i o n s of gr e a t e r than 50% and 20% were de t e c t e d below the foundation s l a b and washroom d r a i n s r e s p e c t i v e l y i n the multi-purpose b u i l d i n g (E.H. Hanson & Assoc., 1985). A gas t r a p was i n s t a l l e d i n the storm sewer, while an a i r i n j e c t i o n gas e x t r a c t i o n system e l i m i n a t e d any methane under the multi-purpose b u i l d i n g i n l e s s than 24 hours a f t e r system s t a r t - u p (E.H. Hanson & Assoc., 1985). In May, 1984, c o n s t r u c t i o n of the gas e x t r a c t i o n u t i l i z a t i o n system was completed. The system o r i g i n a l l y c o n s i s t e d of 16 a i r i n j e c t i o n and 16 withdrawal w e l l s on the nor t h and west perimeter of the l a n d f i l l with 6 f u e l w e l l s l o c a t e d w i t h i n the western p o r t i o n of the re f u s e l a y e r . Because of o f f - s i t e m i g r a t i o n east of the l a n d f i l l , more i n j e c t i o n - w i t h d r a w a l w e l l s (7 and 4 r e s p e c t i v e l y ) were i n s t a l l e d i n e a r l y 1985. A l s o , two more f u e l w e l l s ( F 7 , F 8 ) were d r i l l e d at t h i s time in the more e a s t e r l y p o r t i o n of the l a n d f i l l . The f u e l w e l l s (ones used f o r t h i s study) are 7.5 cm i n diameter, average 9-10 meters i n depth and are p e r f o r a t e d the e n t i r e l e n g t h s t a r t i n g from 1 .5 meters below the l a n d f i l l s u r f a c e . The e x t r a c t e d gas i s c o l l e c t e d and i s f i r s t sent to the compressor and second to the storage pressure tank. The compressed gas (untreated) i s piped to 8 furnaces and a hot 58 water tank l o c a t e d w i t h i n the multi-purpose b u i l d i n g . The furnaces were r e t r o f i t t e d to accept the untreated l a n d f i l l gas, which has only about a 500 BTU/CF hea t i n g value (E.H. Hanson & Assoc., 1985). The s i x f u e l w e l l s were used f o r l e a c h a t e and gas sampling because of t h e i r easy access and l o c a t i o n w i t h i n the l a n d f i l l . Only two w e l l s , F2 and F5 Matsqui c o n t a i n e d l e a c h a t e throughout the study p e r i o d . Wells F1 and F3 began to show l e a c h a t e i n December of 1987 a f t e r heavy r a i n s . Because of sampling problems, F6 was d i s c o n t i n u e d i n mid-November and r e p l a c e d by Well F8. The l o c a t i o n s of a l l sampling w e l l s . a r e l o c a t e d on F i g u r e 3.3. 3.2. STRIDE AVENUE LANDFILL • 3.2. 1 . LOCATION S t r i d e Avenue i s l o c a t e d j u s t upslope of S.E. Marine D r i v e on Burnaby's south slope at approximately 100 meters above mean sea l e v e l (See F i g u r e 3.1, 3.4). T h i s 8.08 ha l a n d f i l l s i t e i s some 1200 meters north of the north arm of the F r a s e r R i v e r (Atwater, 1980). ,3.2.2. PHYSICAL DESCRIPTION The main s i t e was o r i g i n a l l y a g u l l y t h at has s i n c e been f i l l e d (See o r i g i n a l s u r f a c e e l e v a t i o n contours on F i g u r e 3.4). The s i t e i s g e n e r a l l y u n d e r l a i n by post g l a c i a l sands with some g r a v e l . Along the g u l l y f l o o r there i s evidence of interbedded s i l t i n the sandy g r a v e l (Atwater, 1980). Surface water run o f f from the s i t e i s flumed a l o n g s i d e the 59 f i l l and i s d i s c h a r g e d i n t o the g u l l y at the toe of the f i l l . T h i s creek e v e n t u a l l y d i s c h a r g e s i n t o the F r a s e r R i v e r at Byrne Road. There have been e l e v a t e d c o n c e n t r a t i o n s i n the creek of c e r t a i n i n o r g a n i c c o n s t i t u e n t s from l e a c h a t e seepage i n t o the creek. Atwater (1980) v o i c e d a concern about h i g h manganese c o n c e n t r a t i o n s measured downstream of the l a n d f i l l i n 1979 that exceeded the recommended c o n c e n t r a t i o n of 0.2 mg/L i n i r r i g a t i o n water by almost 10 f o l d . Adjacent to the f i l l , groundwater was encountered at a depth of 15 m (Atwater, 1980). T h i s author d e t e c t e d r e d - c o l o u r e d seepage from the t h i c k e r p o r t i o n of the l a n d f i l l n orth of w e l l F7 (See F i g u r e 3.5) a f t e r heavy r a i n s i n e a r l y A p r i l , 1988. Average annual p r e c i p i t a t i o n at t h i s s i t e i s estimated to be about 1270 mm (Atwater, 1980). 3.2.3. HISTORY AND CHARACTERISTICS OF FILL S t r i d e Avenue opened around 1910 f o r r e f u s e d i s p o s a l and c l o s e d i n 1969. Since 1986, the western p o r t i o n of the f i l l has been reopened f o r disposal, of garden wastes and s l a s h f o r Burnaby r e s i d e n t s . T h e o r i g i n a l f i l l i n g o p e r a t i o n proceeded i n a southernly d i r e c t i o n from the north east end of the s i t e (See F i g u r e 3.5). The o p e r a t i o n c o n s i s t e d of g u l l y f i l l with some f i l l i n g of 6-9 m deep sand excavations on the western f l a n k (Atwater, 1980). The f i l l depth i s b e l i e v e d to average 12-14 m but can be up to 27 m deep(Atwater, 1980). E.H. Hanson & Assoc. (1985) used h i s t o r i c a l data with d r i l l hole logs to c o n s t r u c t an isopac map 60 0 SO » 0 2 O 0 300 Scale in M e l r e i FIGURE 3.4 - LOCATION MAP S t r i d e Avenue L a n d f i l l (Map a d a p t e d from A t w a t e r , 1980) Note: E l e v a t i o n c o n t o u r s a r e i n f e e t 61 showing the r e l a t i v e t h i c k n e s s of the l a n d f i l l . I n s p e c t i o n of t h i s map i n d i c a t e s the deepest p o r t i o n of the f i l l to be j u s t north of w e l l s F6 and F7 (See F i g u r e 3.5). The f i l l i s mostly MSW, with l e s s e r amounts of m u n i c i p a l c l e a n i n g d e b r i s (road c l e a n i n g , e t c . ) . , while d e m o l i t i o n and c o n s t r u c t i o n m a t e r i a l was g e n e r a l l y d i r e c t e d elsewhere (Atwater, 1980). F i l l volume and t o t a l mass were estimated by Atwater (1980) to.be 987,000 m3 and 5.3 X 10 8 kg (527,000 tonnes) r e s p e c t i v e l y . Cover t h i c k n e s s i s estimated from d r i l l records by E.H. Hanson & Assoc. to average about 2 meters i n t h i c k n e s s . Near-s u r f a c e samples taken of the cover m a t e r i a l i n d i c a t e a clay-wood c h i p mixture with good, c o n s o l i d a t i o n . T o t a l p o r o s i t y of the cover i s estimated to be about 30% by t h i s author. 3.2.4. GAS EXTRACTION SYSTEM E.H. Hanson & Assoc. began i n v e s t i g a t i n g p o s s i b l e o f f s i t e methane m i g r a t i o n at S t r i d e Avenue in 1981. They implemented a monitoring program complete with a gas w e l l c o l l e c t i o n system that was completed in l a t e 1984. In 1986 new development p r o p o s a l s . t o re-zone the land surrounding S t r i d e Avenue l a n d f i l l c a l l e d f o r more o b s e r v a t i o n w e l l s to be d r i l l e d n o r t h of the l a n d f i l l (See F i g u r e 3.5). One i n c i d e n t of methane e x p l o s i o n d i d occur at the l a n d f i l l i n 1985 d u r i n g c o n s t r u c t i o n of a new storm sewer. However, there i s no documentation of methane mi g r a t i o n t h r e a t e n i n g any o f f s i t e s t r u c t u r e s to date. 62 0 50 100 FIGURE 3.5 - SITE MAP o f S t r i d e Ave. L a n d f i l l ( A d a p t e d from E.H. Hanson & A s s o c . J a n . , 1987) ..' • • 63 O v e r a l l , the system at S t r i d e Avenue has at l e a s t 20 monitoring w e l l s and 8 e x t r a c t i o n w e l l s . The e x t r a c t i o n - f u e l w e l l s range from 8 to 20 m i n depth and are 7.5 cm i n diameter. At c e r t a i n times of the year, gas from these f u e l w e l l s (F1 to F8) i s c o l l e c t e d and sent to the burner housing l o c a t e d on the western p o r t i o n of the f i l l (See F i g u r e 3.5). T h i s burner uses the methane as a f u e l f o r burning r e c e n t l y d e p o s i t e d garden waste and s l a s h . A l s o , when on vacuum, these f u e l w e l l s h e l p to c o n t a i n any o f f s i t e methane m i g r a t i o n . Sample w e l l s used were F2, F3, F6, F7, F8 and B10. L o c a t i o n of these w e l l s are presented i n F i g u r e 3.5. The w e l l s were chosen because a l l w e l l s except F8 contained l e a c h a t e . A f t e r heavy r a i n s , F8 began showing lea c h a t e i n mid-December 1987. Well B10 was o r i g i n a l l y chosen because of i t ' s d i r e c t p r o x i m i t y to the a c t i v e f i l l a r e a . However, t h i s w e l l was b u r i e d by dep o s i t e d garden s l a s h i n mid-October and never sampled ag a i n . A l l other w e l l s i n the a c t i v e f i l l area were i n a c c e s s i b l e f o r . sampling the l e a c h a t e . 3.3. RICHMOND LANDFILL 3.3.1. LOCATION Richmond L a n d f i l l i s l o c a t e d i n the M u n i c i p a l i t y of Richmond j u s t north of the main arm of the F r a s e r River and j u s t south of Westminster Highway ( F i g u r e s 3.1). The l a n d f i l l p r o p e r t y c o n s i s t s of about 270 ha, which, about 20 ha c o n s i s t s of the study s i t e . T h i s study s i t e i s l o c a t e d j u s t o f f No 8 Road at the north end of the l a n d f i l l p r o p e r t y (See F i g u r e 3.6). The 64 e l e v a t i o n of the l a n d f i l l s i t e i s j u s t a few meters above sea l e v e l . 3.3.2 PHYSICAL DESCRIPTION The s i t e r e s t s on a peat bog of t h i c k n e s s up to 5 m which i s u n d e r l a i n by 0.9 to 7.3 m of s i l t and c l a y . T h i s s i l t and c l a y i s u n d e r l a i n by up to a 30 m t h i c k u n i t of d e l t a i c sands (Atwater, 1980). Regional water t a b l e l e v e l s are c l o s e to the ground s u r f a c e at t h i s s i t e . Within the l a n d f i l l , r e fuse l o a d i n g on the peats has caused a concave d e p r e s s i o n to form i n the peats where water t a b l e e l e v a t i o n has become higher than the water l e v e l s of the neighboring F r a s e r R i v e r . Piezometers i n the sand and r e f u s e , l a y e r s show a profound head response to t i d a l f l u c t u a t i o n s , whereas response i n the peat u n i t i s ever i n c r e a s i n g due to the load of the r e f u s e (Atwater, 1980). Average annual p r e c i p i t a t i o n of the s i t e i s j u s t over 1000 mm/year. Cut o f f d i t c h e s were i n s t a l l e d to c o l l e c t l e a c h a t e on the perimeters of the l a n d f i l l i n the mid-1970's. These d i t c h e s d i v e r t l e a c h a t e e i t h e r to the northwest storage lagoons or are d i s c h a r g e d i n t o the F r a s e r River at the Nelson Road pump s t a t i o n . For a more thorough d i s c u s s i o n on le a c h a t e from Richmond l a n d f i l l , r e f e r to Atwater (1980). 3.3.3. HISTORY AND CHARACTERISTICS OF FILL The l a n d f i l l o p e r a t i o n began i n 1971 and ended i n December, 1986 (E.H. Hanson & Assoc., 1988). The l a s t f i l l to be completed ( A d a p t e d from A t w a t e r , 1980) (No s c a l e g i v e n ) . , 66' \" was i n the study area s i t e . Richmond L a n d f i l l , L t d . operated the f i l l o p e r a t i o n s under an agent's agreement with the F r a s e r River Harbour Commission (FRHC), which owns the l a n d f i l l p r o p e r t y . The f i l l i n g o p e r a t i o n c o n s i s t e d of a 1.2 to 2.1 m l i f t of mattress f i l l f o l l o w e d by a second l i f t of 2.4 to 4.3 m of r e f u s e . An a d d i t i o n a l two l i f t s were p l a c e d i n the 20 ha study s i t e . Estimated f i l l d e n s i t i e s f o r the 20 ha study s i t e have not been documented. Older f i l l d e n s i t i e s , before r e g u l a r c e l l c o n s t r u c t i o n techniques were p r a c t i c e d , was estimated at 415 kg/m3 (Atwater, 1980). D a i l y and f i n a l cover was dredged F r a s e r R i v e r sand. The f i n a l cover on the study s i t e i s estimated to average 1.5 m i n t h i c k n e s s (G. Huckulak, pers, comm., 1988) T h i s sand and g r a v e l cover i s u n c o n s o l i d a t e d , h i g h l y permeable, with t o t a l p o r o s i t i e s estimated by t h i s author of over.50%. The high p o r o s i t y of the cover has allowed l a r g e volumes of r a i n water to i n f i l t r a t e the l a n d f i l l , mounding water up to 2 m below the l a n d f i l l s u r f a c e . p The f i l l was c h a r a c t e r i z e d by over 4.4 X 10 kg (435,000 tonnes) of MSW d e p o s i t e d a n n u a l l y , with l a r g e amounts of l i q u i d waste d i s c h a r g e d o n s i t e up to 1978 when t h i s was stopped. Large volumes of c o n s t r u c t i o n and d e m o l i t i o n d e b r i s were a l s o d e p o s i t e d on the l a n d f i l l p r o p e r t y . The 20 ha study s i t e c o n s i s t s s o l e l y . . . Of MSW f i l l . 3.3.4. GAS EXTRACTION SYSTEM About 2 years p r i o r to c l o s u r e of the a c t i v e f i l l a rea, E.H. Hanson & Assoc. approached FRHC f o r a c q u i s i t i o n of l a n d f i l l gas 67 r i g h t s while c o n s u l t i n g the commission on l a n d f i l l gas c o n t r o l measures. Gas c o n t r o l measures were co n s i d e r e d i n an attempt to reduce or e l i m i n a t e the r i s k of gas mig r a t i o n i n t o the planned f u t u r e i n d u s t r i a l park that was to serve new p o r t f a c i l i t i e s along the F r a s e r R i v e r . A f t e r an e x t e n s i v e rod-probe t e s t i n g program of over 270 ha of the p o t e n t i a l developable a r e a , E.H. Hanson prepared recommendations to the FRHC c o n t r o l of l a n d f i l l gas. T h e i r recommendations i n c l u d e d c o n t a i n i n g , e x t r a c t i n g and burning the gas. At t h i s p o i n t , FRHC gave gas r i g h t s to E.H. Hanson & Assoc. in r e t u r n f o r a r o y a l t y payment. They were ab l e to f i n d a customer f o r the gas i n La Farge Cement (See F i g u r e 3.6), which uses the gas i n t h e i r cement k i l n s as a supplementary f u e l ( s u p p l i e s 13% of t h e i r energy requirements). T h i s high k i l n temperature coupled with a long r e t e n t i o n time ensures complete combustion of a l l gas components (E.H. Hanson & Assoc., 1988). Costs f o r t h i s system were shared from Energy, Mines and Resources, Canada ( c o n t r i b u t e d to 18% of c a p i t a l c o s t ) and Bio Gas I n d u s t r i e s of Vancouver, which i s a group of p r i v a t e i n v e s t o r s . At the time, payback f o r i n v e s t o r s was estimated at 3 yea r s . O r i g i n a l c a p i t a l c o s t s were valued at over $500,000. T h i s p r o j e c t i s the only one i n the world s u p p l y i n g l a n d f i l l gas as f u e l to cement k i l n s (E.H. Hanson & Assoc., 1988). I n s t a l l m e n t of the gas c o l l e c t i o n system began i n June 1986 with the i n s t a l l a t i o n of 36 w e l l s on the eas t e r n p o r t i o n of the l a n d f i l l study area (See Fi g u r e 3.7). T h i s p a r t of the system 68 became o p e r a t i o n a l on November 4th, 1986. In e a r l y December of 1986, a f t e r d i s p o s a l o p e r a t i o n s ceased, an a d d i t i o n a l 28 w e l l s were d r i l l e d and put on l i n e by l a t e December. In l a t e 1987, the gas p r o d u c t i o n from t h i s 64 w e l l c o l l e c t i o n system was around • 3 20.5 m /min (725 CFM) while averaging 56.5% methane (E.H. Hanson & Assoc, 1988). E x t r a c t i o n w e l l s are 7.5 cm i n diameter and reach an average depth of 7.5 m i n t o the l a n d f i l l . P e r f o r a t i o n s begin 1.5 m below the top of the c a s i n g and extend f o r the remaining 6m. The borehole i s about 20 cm i n diameter, with g r a v e l f i l l i n g the annular space between the borehole and c a s i n g . In c o n t r a s t to the other three l a n d i l l s s t u d i e d , w e l l head assemblies i n Richmond L a n d f i l l are l o c a t e d above ground. The c o l l e c t i o n system c o n s i s t s of rows of 10 cm diameter PVC p i p i n g where a\"20.cm diameter header connects to each row of t h i s p i p i n g . Each row i s v a l v e d . Condensate d r a i n s are spaced throughout t h i s c o l l e c t i o n system. The gas from the headers i s then routed i n t o , a 25 cm diameter 1.6 km long t r a n s f e r pipe that t r a n s p o r t s the gas to a blower which imparts about 70 cm (28 i n ) of vacuum to t h i s t r a n s f e r l i n e (E.H. Hanson & Assoc., 1988). On the o u t l e t end of the blower i s a 150 cm diameter pressure l i n e with about 12.5 p s i of pressure that t r a n s p o r t s the gas another 1.6 km to the cement k i l n . The pressure of the l i n e when reachin g the k i l n i s about 5 p s i . Blow out v a l v e s to r i d condensate from t h i s l i n e are l o c a t e d throughout the d i s t r i b u t i o n system. No pretreatment of 69 LEACHATE DITCHES o METERS FIGURE 3.7 - SITE MAP Richmond L a n d f i l l ( A d a p t e d from E.H. Hanson & A s s o c . J u l y , 1986) 70 gas i s employed at t h i s s i t e . For a more d e t a i l e d plan of t h i s system r e f e r to E.H. Hanson & Assoc., 1988. Sample w e l l s used i n t h i s l a n d f i l l s i t e were B8,.D9, C6, G7, D.55 and B.53. L o c a t i o n of these w e l l s i s presented i n F i g u r e 3.7. These w e l l s were chosen f o r sampling because of t h e i r easy a c c e s s i b i l i t y , and v a r i e d water l e v e l s . A l s o , sample w e l l s were spaced around the l a n d f i l l f o r a b e t t e r r e p r e s e n t a t i o n of s p a t i a l d i f f e r e n c e s found i n t h i s very heterogeneous f i l l . 3.4 PREMIER STREET LANDFILL 3.4.1. LOCATION Premier S t r e e t L a n d f i l l i s l o c a t e d i n the D i s t r i c t of North Vancouver on the east f l a n k of Lynn Creek, approximately 2 km north of Second Narrows. Bridge (See F i g u r e 3.8). The o v e r a l l s i t e i s approximately 20 ha i n s i z e at a base e l e v a t i o n of about 25 m. 3.4.2. PHYSICAL DESCRIPTION . The l a n d f i l l l i e s on f l u v i a l sands and g r a v e l s , which make up a 2-9 m t e r r a c e j u s t above Lynn Creek. T h i s u n i t i s very coarse and permeable. U n d e r l y i n g t h i s u n i t i s a dense grey s i l t y sand and g r a v e l t i l l . P r evious i n v e s t i g a t i o n s have de t e c t e d upward groundwater seepage from the t i l l i n t o the more permeable f l u v i a l sands and g r a v e l s (Golder Assoc., 1983). T h i s hydrogeologic environment i s s u i t a b l e f o r l a r g e volume d i s c h a r g e s of groundwater i n t o Lynn Creek. A water balance c a l c u l a t i o n done by Golder Assoc. (1983) estimated a groundwater 3 di s c h a r g e of 55,188 m /yr i n t o Lynn Creek from the newer l a n d f i l l 71 s i t e . They mention, however, many of the inputs to the water balance are p o o r l y d e f i n e d . Much of t h i s groundwater i s contaminated by l a n d f i l l l e a c h a t e ; which has been mostly . contained by a dyke and s l u r r y b e n t o n i t e c u t o f f t r e n c h l o c a t e d in one area between the l a n d f i l l boundary and Lynn Creek and another area s e p e r a t i n g the younger from o l d e r f i l l s . A p e r f o r a t e d l e a c h a t e c o l l e c t i o n pipe runs p a r a l l e l to t h i s t r e n c h and dyke adjacent to Lynn Creek to c o n t a i n and d i r e c t the l e a c h a t e to a c e n t r a l c o l l e c t i o n p o i n t f o r f u r t h e r pumping to the m u n i c i p a l sewer system. Average annual p r e c i p i t a t i o n at t h i s s i t e i s the g r e a t e s t of the four s i t e s and i s estimated by Golder, Assoc. (1983) t o be about 1880 mm/yr. 3.4.3. HISTORY AND CHARACTERISTICS OF FILL The D i s t r i c t of North Vancouver began f i l l o p e r a t i o n s i n 1959 and ceased o p e r a t i o n s i n the a c t i v e f i l l area i n the Spring of 1988 (See F i g u r e 3.8). The study s i t e i s l o c a t e d i n the o l d e r f i l l , which completed o p e r a t i o n s i n 1981 (Peddie, 1986). The study s i t e c o n s i s t s of an area f i l l up to 25 m deep. It i s understood that c o n s t r u c t i o n of the o l d e r l a n d f i l l was preceeded by c o n s t r u c t i n g a 6 m high dike of loose s i l t y sand and g r a v e l along the east bank of Lynn Creek. In a d d i t i o n , c o n s t r u c t i o n of a mattress l a y e r of impermeable mineral f i l l preceeded normal f i l l o p e r a t i o n s (Golder Assoc., 1983). T h i s o l d e r f i l l area i s now used f o r r e c r e a t i o n a l b a l l f i e l d s and t e n n i s c o u r t s . I t i s g e n e r a l l y understood a l l types of m a t e r i a l , FIGURE 3.8 - LOCATION MAP P r e m i e r S t r e e t L a n d f i l l ( Adapted from G o l d e r A s s o c . , 1983) 73 i n c l u d i n g l i q u i d waste, were accepted f o r d i s p o s a l at Premier S t r e e t throughout the 1960's. The l a n d f i l l cover around the study s i t e was found to be compacted a l t e r e d c l a y and shale d e b r i s with an estimated t o t a l p o r o s i t y of 25%. 3.4.4. GAS COLLECTION SYSTEM In 1985, an e x t r a c t i o n and f l a r i n g system was i n s t a l l e d to c o n t r o l Or reduce odorous emissions from Premier S t r e e t L a n d f i l l . The f l a r e stack i s l o c a t e d j u s t west of the weigh s c a l e and was 3 i n March, 1986 r e c e i v i n g approximately 8.5 m /min (300 CFM) of e x t r a c t e d l a n d f i l l gas (E.H. Hanson & Assoc., 1986). P r e s e n t l y on s i t e there are 21 e x t r a c t i o n w e l l s of 7.5 cm i n diameter that average 20 m deep. A d d i t i o n a l gas c o l l e c t i o n i s through a p e r f o r a t e d pipe system b u r i e d i n the most r e c e n t l y completed f i l l area (See F i g u r e 3.9). T h i s c o l l e c t i o n network has been found to be very i n e f f i c i e n t , ( E . H . Hanson & Assoc., 1986). Plans f o r the f u t u r e i n c l u d e w e l l i n s t a l l a t i o n i n t o the now a c t i v e p o r t i o n of the f i l l f o r f u r t h e r c o n t r o l of odors. My reasons f o r using only two w e l l s \" ( P I and P2) f o r sampling at t h i s s i t e was due to t h e i r a c c e s s i b i l i t y f o r downhole l e a c h a t e c o l l e c t i o n . A l l other w e l l s on s i t e had a seperate below ground c o n t r o l v a lve assembly with an i n a c c e s s i b l e b u r i e d w e l l head that was impossible to c o l l e c t l e a c h a t e from. . 74 FIGURE 3.9 - SITE MAP P r e m i e r S t r e e t L a n d f i l l ( A d a p t e d from E.H. Hanson & A s s o c . March, 1986) ( E l e v a t i o n c o n t o u r s s k e t c h e d from G o l d e r A s s o c . , 1983) 75 CHAPTER 4 4. METHODOLOGY 4.1. FIELD METHODS 4.1.1. INSTRUMENTATION AND TECHNIQUE Parameters that were measured on s i t e i n c l u d e leachate pH, water l e v e l , ambient a i r , gas and leachate temperature, barometric pressure, and l a s t l y , s t a t i c gas flow. Samples c o l l e c t e d f o r l a b a n a l y s i s i n c l u d e leachate samples, gas samples for gas p a r t i t i o n e r a n a l y s i s , and NHg-N gas samples for autoanalyzer a n a l y s i s . The f o l l o w i n g instruments were used i n the f i e l d : A. Leachate C o l l e c t i o n Leachate was c o l l e c t e d from 7.5 cm diameter gas e x t r a c t i o n wells with two d i f f e r e n t diameter PVC b a i l e r s . The b a i l e r s were both about 1 meter i n length and v a r i e d i n diameter from 2.2 cm (ID) to 3.75 cm (ID). Leachate entered the bottom of the b a i l e r through a 4 mm diameter p l a s t i c check v a l v e . These check v a l v e s were l o o s l y f i t t e d and e a s i l y removed for c l e a n i n g when the v a l v e got clogged, which i t d i d f r e q u e n t l y . The smaller diameter b a i l e r was used at Richmond and Premier St. L a n d f i l l s because the la r g e r b a i l e r got hung up in these l a n d f i l l w e l l c a s i n g s . Leachate was c o l l e c t e d i n 500 mL p l a s t i c b o t t l e s a f t e r d i s c a r d i n g two b a i l e r volumes of leac h a t e . A f t e r l a b a n a l y s i s of the samples, both the b a i l e r and b o t t l e s were a c i d washed. Water l e v e l s i n the wells were measured by the c a l i b r a t e d nylon rope that lowers the b a i l e r i n t o the w e l l . O r i g i n a l l y , a 76 s t e e l s urveying tape was employed, but was found to be r u s t i n g , so i t was d i s c o n t i n u e d . As the b a i l e r encounters l e a c h a t e , a tugging motion from l e a c h a t e s u r f a c e t e n s i o n i s e a s i l y f e l t on the rope. At t h i s time, the spot where the rope and wellhead top match i s marked and measured by a c a r p e n t e r ' s tape to a known leng t h on the rope. A t a r e of 1.64 m i s added to to t h i s l e n g t h to account f o r the l e n g t h of the b a i l e r and rope from the d e f i n e d zero mark on the rope. B. S t a t i c Gas Flow For w e l l flows of approximately 8.0 L/min and over, a Rockwell I n t e r n a t i o n a l RC-230 r e s i d e n t i a l gas flow meter was used. For s t a t i c flows g e n e r a l l y l e s s than t h i s , the pressure flow was not great enough to t u r n the crank bracket i n the meter, so a l t e r n a t i v e meters were t r i e d . Both bubble flow and d i a l flow meters were t r i e d , but had problems because tubing adapters were i n s t a l l e d to match the flow meter's 1 cm diameter o u t l e t with the w e l l head 2.5 cm (ID) diameter sample t u b i n g . In t u r n , t h i s flow c o n s t r i c t i o n decreased flow r a t e s to g i v e erroneous r e s u l t s . I s o l v e d the problem by going to s m a l l , o n e - l i t e r p l a s t i c Safeway c o f f e e bags that were e a s i l y c a l i b r a t e d to 0.5 and 1.0 l i t e r volumes. To c a l c u l a t e flow r a t e , a stop watch was used to measure the time i t took to f i l l up the l i t e r bag. T h i s technique i s e r r o r prone, probably 15 to 20 % e r r o r , but was the only f e a s i b l e technique a v a i l a b l e at the time. The RC-230 r e s i d e n t i a l flow meter has a r a t e d flow c a p a c i t y of 230 SCFH (110 L/min) and a t o t a l percent e r r o r of l e s s than 77 1%. Greater e r r o r may e x i s t i n some measurements where w e l l flow was measured above 110 L/min ( i e , D9 and C6 Richmond). C. Barometric Pressure Barometric pressure was measured by a \"Baromaster\" barometer that was c a l i b r a t e d every two weeks from the Vancouver I n t l . A i r p o r t Environment Canada weather s t a t i o n on the way to sampling Richmond l a n d f i l l . Accuracy of t h i s instrument was not documented i n the user manual. D. Temperatures Ambient a i r , l a n d f i l l gas and le a c h a t e temperatures were measured by a normal m e r c u r y - f i l l e d g l a s s thermometer. T h i s thermometer was encased i n an unbreakable s t a i n l e s s s t e e l sheath and lowered on s t r i n g w i t h i n the w e l l to approximately 1 to. 2 m above the water l e v e l to r e c o r d w e l l gas temperature. Problems with t h i s method i n c l u d e w e l l c a s i n g condensate c o n t a c t i n g the thermometer. Leachate temperature was measured once the le a c h a t e was i n the sample b o t t l e . E. pH Leachate pH was determined l e s s than 5 minutes a f t e r c o l l e c t i o n to guard a g a i n s t erroneous readings due to carbonate e q u i l i b r i a s h i f t s . These e q u i l i b r i a s h i f t s commonly occur from pressure and temperature changes of the l e a c h a t e when the sample i s brough up and out of the w e l l . The f i e l d pH meter used was a Horizon #5996-30 b a t t e r y - o p e r a t e d L C D - d i g i t a l d i s p l a y meter. The power source i s a Ni-Cadmium rechargeable b a t t e r y . The pH e l e c t r o d e used was a 91-06 Orion epoxy body g e l - f i l l e d 78 combination general purpose e l e c t r o d e . C a l i b r a t i o n of the meter with pH 7.0 b u f f e r standard was p r a c t i c e d f i r s t t h i n g every morning at s i t e and was checked p e r i o d i c a l l y f o r c a l i b r a t i o n decay. Decay was never found to be a problem as long as the meter was s e t . i n stand-by mode between readings. T h i s pH meter a l s o was equipped with manual temperature c o r r e c t i o n . Documented accuracy of the pH meter i s re p o r t e d at — 0.01 pH u n i t s with a r e s o l u t i o n of + 0.01 pH u n i t s . R e s u l t s of an accuracy comparison made i n t h i s study are summarized i n Appendix A.7 and d e t a i l e d i n Appendix A.6. 4.1.2. NH3-N GAS SAMPLING TECHNIQUE NH3-N from l a n d f i l l gas was sampled using a gas bubbler c o n t a i n i n g a t r a p p i n g s o l u t i o n of 20,000 ppm of b o r i c a c i d . T h i s a c i d bubbler technique i s common f o r sampling atmospheric ammonia (see NRC, 1 979)-, • while \"using'H 2S0 4 i n s t e a d of H3BC>3. The technique i s f e a s i b l e f o r sampling low NH3-N c o n c e n t r a t i o n s because l a r g e volumes of gas can be passed through the s o l u t i o n c o n c e n t r a t i n g the s o l u t i o n enough to be d e t e c t e d by normal a n a l y t i c a l techniques. A schematic of t h i s simple sampling technique i s shown i n F i g u r e 4.1. In summary, l a n d f i l l gas i s pumped from the e x t r a c t i o n w e l l at around 6 L/min i n t o the gas bubbler (#8 on F i g . 4.1) where ammonia i s protonated to NH^ +, which then stays i n s o l u t i o n by r e a c t i o n ( i ) : NH 3 + H + + H 2B0 3~ ---> NH 4 + + H 2B0 3~ ( i ) B o r i c a c i d i s used as the t r a p p i n g s o l u t i o n because i t i s 79 easy to handle i n the f i e l d (a very weak a c i d ) , simple and inexpensive to prepare, and l a s t l y , i t showed the same NH3-N r e t e n t i o n c a p a c i t y as 0.1N H2S04 and o x a l i c a c i d i n l i m i t e d t e s t s run. . The gas bubbler i s a g l a s s F i s h e r - M i l l i g a n \"gas washer\" that i s s e a l e d at the screw-off cap by a rubber cap gasket. Connected on the.cap i s a g l a s s flow tube where pumped gas flows through a 1.5 mm diameter flow c o n s t r i c t i o n f o r maximum d i s p e r s i o n and out i n t o the b o r i c a c i d s o l u t i o n . Within the g l a s s bubbler, i s a s p i r a l network of channeled g l a s s which maximizes co n t a c t time of. the bubble and s o l u t i o n . A s o l u t i o n volume of around 70 mL was found to be optimal s i n c e g r e a t e r volumes seemed to leak from the cap gasket. The sampling pump used i s a Cole Parmer diaphragm-operated \" A i r Cadet\" pump s p e c i a l l y designed f o r p r e s s u r e s u c t i o n and gas c i r c u l a t e d a p p l i c a t i o n s . T h i s s i n g l e - s p e e d pump r e q u i r e s 12 v o l t b a t t e r y power and can handle max. pressure loads of 15 p s i g . Maximum vacuum and gas flow are r a t e d at 18 i n . Hg and 18.8 L/min. The 12 v o l t pump motor has a c a p a c i t y of 1/30 hp at 1650 RPM. Throughout the study p e r i o d , the pump operated at around 6 L/min flow with o c c a s i o n a l flow decrease from p a r t i c u l a t e matter c l o g g i n g the v a l v e s e a t s . The RD-230 gas flow meter was used to r e c o r d the cumulative volume i n l i t e r s , of gas that passed through the bubbler. To get ample NH^-N mass for a n a l y s i s , sampling was c a r r i e d out f o r 30 minutes which r e s u l t s i n j u s t under 200 l i t e r s of t o t a l gas 80 1. Gas e x t r a c t i o n w e l l 2. S p e c i a l PVC w e l l cap 3. 1\" (2.5 cm) d i a m e t e r t y g o n t u b i n g 4. RD-240 Gas f l o w meter 5. T u b i n g r e d u c e r s from 1\" down to 3/8\" (1.0 cm) 6. 3/8\" t y g o n t u b i n g 7. \" A i r C a d e t \" 12 v o l t pump 8. Gas b u b b l e r FIGURE 4.1 - Schematic f o r NH3-N gas s a m p l i n g 81 volume being passed through the b o r i c a c i d sample. In order to decrease the p o t e n t i a l f o r a i r and/or r a i n f a l l c ontamination, funnels were used to pour bubbler s o l u t i o n and sample i n t o t h e i r r e s p e c t i v e c o n t a i n e r s . E v a p o r a t i o n of sample and ammonia contamination from human breath were c o n s i d e r e d n e g l i g i b l e . A f t e r sampling, the gas bubbler was r i n s e d 2 times with ammonia-free d i s t i l l e d water. A f t e r every sampling run, the bubbler was throughly soaked i n HC1 c l e a n i n g a c i d . Problems encountered d u r i n g sampling i n c l u d e d d i r t and sand i n t r u s i o n i n t o samples and condensate b u i l d - u p .on sampling tubes. Condensate was e s p e c i a l l y apparent at Richmond l a n d f i l l where the l a n d f i l l gas i s s a t u r a t e d with water vapor. A major concern with t h i s condensate b u i l d - u p was the p o t e n t i a l s o r p t i o n of NH^-N onto the moistened sample tubes. On a number of o c c a s i o n s , t h i s condensate was sampled at the end of the day by f l u s h i n g the tube with 100 mL of d i s t i l l e d water. \\ Two ways were attempted to decrease condensate b u i l d - u p on the tubes. One was to shorten the sample tube l e n g t h , which d i d not help any, and two, was to i n s e r t a c o t t o n plug at the f r o n t end of the tube. The c o t t o n plug was found to.be tod porous i n d e c r e a s i n g condensate b u i l d - u p . I a l s o r i n s e d the c o t t o n plug a f t e r use and analyzed i t on the autoanalyzer only to f i n d no t r a c e of NH3-N. The same problems o c c u r r e d when using a Whatman No. 41 f i l t e r i n s t e a d of the c o t t o n p l u g . One way I d i d not t r y i s wrapping the sample t r a i n with thermal h e a t i n g tape to keep the temperature above the dew p o i n t 82 of the gas while sampling. Other than using the Whatman 41 f i l t e r f o r r i d d i n g the condensate b u i l d up, I d i d not at any other time p r e f i l t e r the l a n d f i l l gas before the sampling bubbler. P r e f i l t e r i n g i s done to r i d the gas of any i n t e r f e r r i n g NH 4 + that may be bound w i t h i n the p a r t i c u l a t e a e r o s o l . However, i n hig h humidity environments l i k e l a n d f i l l gas, the f i l t e r medium can become a s u b s t a n t i a l removal mechanism of ammonia gas. Much of t h i s sorbed ammonia co u l d be protonated to NH 4 + i n the presence of a c i d - c o n t a i n i n g a e r o s o l s . T h i s may be true i n l a n d f i l l gas where c h l o r i n a t e d hydrocarbons can react with water to form HC1 on the f i l t e r medium. Work would need to be done to s u b s t a n t i a t e t h i s c l a i m . In r e a l i t y then, the ammonia gas a n a l y s i s i s a c t u a l l y + + measuring t o t a l ammonia (NH^ + NH^). The c o n t r i b u t i o n of NH^ in my a n a l y s i s i s q u e s t i o n a b l e . Koike et a l . (1973) found that by not p r e f i l t e r i n g atmospheric gas streams f o r ammonia a n a l y s i s r e s u l t s i n a p o s i t i v e e r r o r of around 30 % r e s u l t s when not p r e f i l t e r i n g the atmospheric gas stream d u r i n g ammonia sampling ( i n NRC, 1979). In l a n d f i l l gas t h i s c o n t r i b u t i o n c o u l d be l e s s because a s a t u r a t e d l a n d f i l l environment i s probably a much more e f f i c i e n t sink f o r a e r o s o l n u c l e i than i n the atmosphere. 4.1.3. VOLATILE ORGANIC SAMPLING The main goal of t h i s phase of the sampling program was to q u a l i t a t i v e l y c h a r a c t e r i z e or f i n g e r p r i n t the -types' of non-polar o r g a n i c s present w i t h i n the l a n d f i l l gas. The sampling technique was kept very simple and was l i m i t e d to t r a p p i n g only non-polar 83 organic contaminants. The sample t r a i n c o n s i s t e d of one Tenax GC a d s o r p t i o n t r a p . The s i m p l i c i t y of the sample t r a i n c o n t r a s t s g r e a t l y to the e l a b o r a t e sampling setups suggested, by Krost et a l . (1982), Bruckmann and M u l l e r (1982), Brookes and Young (1983) and Young and Parker (1984). The Tenax GC 60/80 t r a p s were c o n s t r u c t e d from 1/4 in c h (OD) brass i n 3.5 i n . l e n g t h s . Tenax GC m a t e r i a l i s packed w i t h i n the t r a p and brass f i t t i n g s are connected to each end of the t r a p . P r i o r to sampling, the Tenax t r a p s were c o n d i t i o n e d overnight at 300 oC. Once sampling was completed, the t r a p s were capped by brass f i t t i n g s and returned to the l a b f o r GC-MS a n a l y s i s ( d i s c u s s e d l a t e r i n t h i s s e c t i o n ) . L a n d f i l l gas organic contaminants were f i r s t sampled i n l a t e January, 1988 at Premier St. l a n d f i l l . In a d d i t i o n to t h i s sample, the next two samples from F5 Matsqui and C6 Richmond were trapped s o l e l y using w e l l flow. At a l l three w e l l s , w e l l flow had to be reduced to approximately 40 mL/min to decrease the p r o b a b i l i t y of any organic breakthrough out the end of the t r a p . Sampling proceeded f o r 20 minutes to pass a cumulative volume of 800 mLs through the t r a p . A f t e r the samples were analyzed, p o t e n t i a l contamination from the sample tubing was n o t i c e d , so the sampling technique was mo d i f i e d . To c o r r e c t t h i s problem, two SKC model 222-3 v a r a i b l e flow p e r s o n a l sampler pumps from the UBC Health and Epidemiology Dept. were l o c a t e d . These pumps a l l e v i a t e d the problem of tubing contamination s i n c e the Tenax t r a p s c o u l d be p l a c e d d i r e c t l y i n 84 the w e l l with s u c t i o n being a p p l i e d v i a the pump. Sample time was i n c r e a s e d to 40 min at a r a t e of 48 mL/min to get a much great e r volume of gas through the t r a p s . T h i s improved sampling technique r e s u l t e d i n a much g r e a t e r d e t e c t i o n of organic contaminants as w i l l be shown l a t e r . In Well C6, condensate b u i l d - u p on the t r a p s was found to be a problem d u r i n g sampling. 4.2. LABORATORY METHODS 4.2.1. INSTRUMENTATION AND TECHNIQUE 4.2.1.1. LEACHATE CONSTITUENTS The a n a l y t i c a l methods used i n t h i s study of non-metal leachate c o n s t i t u e n t s are d e s c r i b e d i n d e t a i l i n Standard Methods, 16 E d i t i o n , except where noted. A. A l k a l i n i t y The t i t r a t i o n was performed to the pH 4.5 end p o i n t using a Beckman 44 pH meter as per the 16th ed. of Standard Methods. B. Chemical Oxygen Demand (COD) COD measurement was done by employing the c l o s e d refux, t i t r i m e t r i c technique as adapted f o r UBC as a l a b standard from the 13th ed. of Standard Methods. C. T o t a l and Organic Carbon Both carbon forms were measured using a dual channel Beckman 915A T o t a l Carbon Analyzer (TOCA) with a model 865 Beckman i n f r a -red d e t e c t o r . The c h a r t recorder was a Kipp and Zonen BD41. Accuracy of t h i s method i s documented at 1 % of f u l l s c a l e . 85 D. T o t a l V o l a t i l e A c i d s (TVA) The d i s t i l l a t i o n method i n Standard Methods, 16th ed. was employed. T h i s method i s l i m i t e d to d e t e c t i o n of organic a c i d s c o n t a i n i n g up to s i x carbon atoms. E. T o t a l and V o l a t i l e S o l i d s Same method used i n Standard Methods, 16th e d i t i o n . Leachate samples of 20 mLs were used. 4.2.1.2. SPECIFIC CONDUCTIVITY S p e c i f i c c o n d u c t i v i t y of the leachate were measured i n the l a b o r a t o r y because no f i e l d meters were a v a i l a b l e at the time. The l a b c o n d u c t i v i t y meter was a Radiometer CDM3 with a model CDC 304 platinum e l e c t r o d e . Measuring accuracy i s +.0.6 % of the standard d e v i a t i o n , except i n measurements l e s s than 500 umho/cm, where the accuracy decreases to + 1.5 % of the standard d e v i a t i o n . The platinum e l e c t r o d e has a c e l l constant of 1.00 cm 1 + 10 %. The meter has a c e l l constant c o r r e c t i o n d i a l which i s used before sample a n a l y s i s f o r c a l i b r a t i o n with 0.01 N KC-1 s o l u t i o n . 4.2.1.3. NH3-N DISTILLATION-TITRATION ANALYSIS Leachate samples were analyzed with the technique as re p o r t e d i n the 16th e d i t i o n , Standard Methods. Accuracy of t h i s method has been repo r t e d to have a s t d . d e v i a t i o n of as great as 21.6 % f o r the lowest c o n c e n t r a t i o n measured of 1.5 mg/L. E r r o r s i n t h i s method c o u l d r e s u l t from volume measurement e r r o r s and i n c o n s i s t e n t a c i d n o rmality of the 0.02 N H 2S0 4. 86 4.2.1.4. GAS CHROMATOGRAPHY/MASS SPECTOMETRY ANALYSIS Q u a l i t a t i v e a n a l y s i s of the trapped v o l a t i l e o r g a n i c s were done on a Hewlett-Packard GC/MS model 5985B equipped with a HP 7576 Purge and Trap d e v i c e . The trapped o r g a n i c s were subjected to thermal d e s o r p t i o n which i n v o l v e s the process of f l a s h h e a t i n g the Tenax GC t r a p with a flow of helium c a r r i e r gas. T h i s r e l e a s e s the l a n d f i l l gas o r g a n i c s that are subsequently c a r r i e d by helium gas i n t o a GC column where chromatographic s e p a r a t i o n takes p l a c e . T h i s s e p a r a t i o n produces peaks of compounds when, e l u t e d from the column. These peaks are de t e c t e d by a e l e c t r o n impact d e t e c t o r (EID). The compounds are f u r t h e r s u b j e c t e d to a quadrapole mass spectrometer which analyzes the generated mass s p e c t r a . The i d e n t i f i c a t i o n of these seperate organic compounds were achieved by l i b r a r y matching of the EPA/NIH Mass Spectra. L i b r a r y Data Base, and comparisons with p u b l i s h e d mass s p e c t r a . The p h y s i c a l c o n d i t i o n s used f o r these GC/MS a n a l y s i s are presented below: Desorb Temperature and Time : 180°C f o r 6 min Column Type and Dimensions : Durawax Megabore C a p i l l a r y column 50 % phenyl methyl s i l i c o n e , 0.53 mm (ID) x 15 m Temperature Program : 30(4 min hold) - 265°C @ 5°C/min I n t e r f a c e Temperature : 250°C Ion Source Temperature : 200°C Scanning Parameters : 40-450 atomic mass u n i t s @ 1.5 A/D Problems encountered with t h i s t r a p a n a l y s i s i n c l u d e some contamination of both tubing and t r a p bleed (styrenes and methyl 87 styrenes found), and poor chromatography, maybe due to CO^ and water vapor i n t e r f e r e n c e . 4.2.1.5. METHANE GAS ANALYSIS A F i s h e r Model 29 Gas P a r t i t i o n e r . w a s used to separate common l a n d f i l l gas components methane, carbon d i o x i d e , n i t r o g e n and oxygen i n t o d i s c e r n i b l e peaks. These e l u t e d peaks are detected by a thermal c o n d u c t i v i t y c e l l c o n t a i n i n g four tungsten f i l a m e n t s ; two f o r r e f e r e n c e and two f o r d e t e c t i o n of the r e s u l t a n t change i n thermal conductance when a gas compound passes by. The d e t e c t o r records these peaks on a Hewlett Packard 3380A I n t e g r a t o r , which with proper c a l i b r a t i o n , records these peaks as % volume of gas. O r i g i n a l l y , the gas i s c o l l e c t e d i n the f i e l d by 50 mL g l a s s v i a l s that have a rubber septum withdrawl p o i n t and p l a s t i c stopcock i n l e f o u t l e t v a l v e s . When returned to the l a b , a 1 mL s y r i n g e withdraws gas from the v i a l and i n j e c t s i t d i r e c t l y i n t o the Gas P a r t i t i o n e r . The two columns used to separate gas components are column 1:6 f t x 1/4 i n aluminum packed with 30 % DEHS on 60/80-mesh chromosorb; column 2: 6 1/2 f t x 3/16 i n aluminum packed with 40/60-mesh Molecular Sieve 13x. C O 2 i s separated through column 1, while other gases are separated through column 2. C a r r i e r helium gas flows at 40 mL/min. The thermal c o n d u c t i v i t y . d e t e c t o r temperature i s around 70 °C. . R e p r o d u c i b i l i t y of t h i s method i s documented at + 1 %. R e s u l t s summarizing the accuracy of .10 i n j e c t i o n s of a standard 88 gas sample are l i s t e d i n Appendix A.7. Raw data f o r t h i s t e s t i s presented i n Appendix A.1. In terms of p o t e n t i a l e r r o r , my main concern r e s u l t e d from leakage from sample v i a l s d u r i n g the time a f t e r sampling and before Gas P a r t i o n e r i n j e c t i o n . T h i s concern warranted a i n v e s t i g a t i o n i n t o t h i s where a l l s i x sample v i a l s were t e s t e d f o r leakage over a 2 day p e r i o d . The gas source was the l a b o r a t o r y n a t u r a l gas l i n e that had over 80 % methane by volume. There was subsequent leakage i n the v i a l s as i n d i c a t e d i n Appendix A.7. D e t a i l e d data f o r t h i s t e s t can be found i n Appendix A.2. Other e r r o r s i n t h i s a n a l y s i s c o u l d stem from the leaky i n j e c t i o n septum a l r e a d y mentioned or from i n c o n s i s t e n t i n j e c t i o n volumes. To ensure no l a b a i r i n t r u s i o n , the i n j e c t i o n septum was r e p l a c e d a f t e r every 25 to 30 i n j e c t i o n s . 4.2.2. AMMONIA GAS ANALYSIS T h i s s e c t i o n i s concerned with d e s c r i b i n g the l a b o r a t o r y . a n a l y s i s of ammonia gas samples c o l l e c t e d i n the f i e l d . A f t e r r e t u r n i n g the 70 mL b o r i c a c i d samples to the l a b , they were r e f r i d g e r a t e d at 4°C or immediately analyzed. No a c i d p r e s e r v a t i o n of the samples was needed s i n c e the b o r i c a c i d samples were a l r e a d y at pH 4.0. Headspace l o s s of NH^ was c o n s i d e r e d n e g l i g i b l e d u r i n g t r a n s p o r t and storage of samples. Samples were analyzed on the Technicon Autoanalyzer II w i t h i n 3 weeks a f t e r sampling. No sample decay d u r i n g t h i s p e r i o d was assumed to occur s i n c e b o r i c a c i d NH^-N standards were found to stay s t a b l e f o r w e l l over a month. 89 The b o r i c a c i d NH^-N standards had NH^-N c o n c e n t r a t i o n s of 0.0, 0.05, 0.1, 0.2, 0.5, 1.0 mg/L and were loaded ahead and behind the samples on the Technicon autosampler rack. A l l standards and samples were analyzed i n t r i p l i c a t e . This autoanalyzer uses the automated phenate method to analyze t o t a l ammonia (NH^-N). As a l r e a d y mentioned, samples can be analyzed at a rate of 60/hr when loaded with a 6:1 cam. The technique i s simply a r e a c t i o n of ammonia with a sodium phenate and h y p o c h l o r i t e s o l u t i o n i n a l k a l i n e c o n d i t i o n s . T h i s forms a quinochloramine compound that e x h i b i t s a d i s t i n c t blue c o l o r c a l l e d indophenol blue. The blue c o l o r formed i s i n t e n s i f i e d f u r t h e r with the a d d i t i o n of the reagent sodium n i t r o p r u s s i d e (Na 2Fe(CN) 5NO\"2H 20). This indophenol r e a c t i o n i s c a t a l y z e d by heating of the s o l u t i o n at 50°C. The indophenol r e a c t i o n i s shown below in Figure 4.3.: FIGURE 4.3 - Indophenol Blue Reaction (Taken from NRC,1979) NHj + HOC! = NH,CI + H,0 indophenol blue 90 The r e s u l t a n t c o l o r i n t e n s i t y at 630 nm i s analyzed i n a mm tub u l a r flow c e l l by a c o l o r i m e t e r . T h i s s i g n a l i s then t r a n s l a t e d onto a Kipp and Zonen BD41 chart r e c o r d e r . A flow chart of the complete Technicon Autoanalyzer II i s shown in Figure 4.4. FIGURE 4.4 - Technicon Autoanalyzer Flow Chart (From Standard Methods, 16th Ed., 1985) Washwater to Sampler Mixing Coi l , Mixing Coil ! Heating Bath 50'C Waste Proportioning Pump mL/min Sampler 60 /h . 6:1 W Black Blue 2.0 Wash 0.23 A i r ' 0.42 Sample 0.8 EDTA 0.42 Phenolate 0.32 Hypochlorite 0.42 Nitroprusside 1.6 Waste Recorder Digital Printer Colorimeter 50-mm Flow Cell 630-nm Filter 'Scrubbed Through 5M H 2 S 0 4 91 The peaks from the samples are t r a n s l a t e d onto a standard c a l i b r a t i o n curve to get NH^-N i n the sample (mg/L). T h i s ammonia c o n c e n t r a t i o n i s then m u l t i p l i e d by the sample volume (around 70 mL) to get the mass of NH^-N i n the sample. T h i s mass i s then d i v i d e d i n t o the t o t a l l a n d f i l l gas volume that passed through the bubbler and m u l t i p l i e d by 10^ to convert the 3 c o n c e n t r a t i o n i n t o ug/m . T h i s c o n c e n t r a t i o n i s then converted l a t e r i n t o ppb as shown i n Appendix B.4. The advantages to using t h i s automated phenate technique f o r ammonia gas are as f o l l o w s : a. The automated indophenol-blue method i s a proven a n a l y t i c a l technique f o r t r a c e l e v e l s of NH3-N gr e a t e r than 0.02 mg/L. • . . b. Can analyze a l a r g e amount of samples i n a small p e r i o d Of time (60 samples/hr). c. Not a l a b o r - i n t e n s i v e technique, except f o r p r e p a r a t i o n of standards and reagents. d. F l e x i b i l i t y of a n a l y t i c a l technique to have the freedom to modify the a n a l y t i c a l set-up., f p r s p e c i a l needs, such as r e p l a c i n g c e r t a i n reagents with other ones l e s s a f f e c t e d by p o t e n t i a l i n t e r f e r e n c e s . T h i s technique w i l l be d i s c u s s e d i n d e t a i l l a t e r . 4.3. PRECIPITATION STATIONS P r e c i p i t a t i o n data f o r each l a n d f i l l s i t e was c o l l e c t e d from the c l o s e s t c e r t i f i e d weather s t a t i o n operated by Environment Canada. The three s t a t i o n s used and t h e i r r e s p e c t i v e l a n d f i l l ( s ) are l i s t e d below: Vancouver I n t e r n a t i o n a l A i r p o r t - L a t . Long.: 49.11 - 123. 10 - E l e v a t i o n : 2.0 m - L a n d f i l l s : S t r i d e Ave. and Richmond Vancouver Harbour - Lat. Long.: 49.18 - 123.10 - E l e v a t i o n : Sea L e v e l - L a n d f i l l : Premier St. Abbotsford S t a t i o n - Lat. Long.: 49.02 - 122.22 - E l e v a t i o n : 58.0 m - L a n d f i l l : Matsqui 4.4. BASIC DATA PARAMETERS MONITORED The data c o l l e c t e d for a l l parameters in each w e l l i s l i s t e d on t a b l e s in Appendix D. A s s o c i a t e d s t a t i s t i c s f o r each parameter i s l i s t e d below the b a s i c data for' each w e l l . S t a t i s t i c s c a l c u l a t e d f o r each parameter were max, min, mean, standard d e v i a t i o n and % c o e f f i c i e n t of v a r i a t i o n (C.V.). The s t a t i s t i c s help i n understanding the v a r i a n c e of each parameter c o l l e c t e d . 4.5. NON-BASIC DATA PARAMETERS There are a number of parameters that were c a l c u l a t e d from the b a s i c data measurements or c o l l e c t e d elsewhere. These parameters i n c l u d e : N 2 / O 2 gas r a t i o , CH 4 f l u x , C0 2 f l u x , gas d e n s i t y , leachate i o n i c s t r e n g t h and a c t i v i t y c o e f f i c i e n t , and l a s t l y , s i t e p r e c i p i t a t i o n . These parameters are l o c a t e d i n Appendix E presented i n t a b l e s j u s t l i k e the basic data. S t a t i s t i c s on these parameters was not attempted since most of them are a f u n c t i o n of the basic data. Examples of how each of these parameters were estimated or c a l c u l a t e d i s presented i n Appendix B. 93 4.6. STATISTICAL ANALYSIS DONE ON PARAMETERS In a d d i t i o n to the s t a t i s t i c s done on the basic data, there were a number of other a n a l y s i s done on the data to one, h e l p de s c r i b e c a u s a l r e l a t i o n s h i p s between parameters and two, t r y to p r e d i c t both NH^-N gas and CH 4 % through the r e g r e s s i o n of f i t t e d parameters. These s t a t i s t i c s i n c l u d e : l i n e a r b i v a r i a t e r e g r e s s i o n , non-parametric K-S normality t e s t s , Pearson product-moment c o r r e l a t i o n and l a s t l y , m u l t i p l e r e g r e s s i o n . Except f o r the b i v a r i a t e l i n e a r r e g r e s s i o n , a l l other s t a t i s t i c s were run on the UBC MTS mainframe program SPSS:X. 4.6.1. LINEAR BIVARIATE REGRESSION Regression was done on s i x parameters versus NH^-N gas i n a f i r s t attempt to determine any r e l a t i o n s h i p s between parameters and NH^-N i n gas. These r e g r e s s i o n s were run on a LOTUS 1-2-3 spreadsheet and were s p e c i f i c to each w e l l . Parameters that were analyzed i n c l u d e : gas temp., pH, i o n i c s t r e n g t h , NH^-N i n leachate, CH^ f l u x and C0 2 f l u x . 4.6.2. PEARSON PRODUCT MOMENT CORRELATION C o r r e l a t i o n matrices were c a l c u l a t e d f o r each w e l l i n v o l v i n g 13 v a r i a b l e s to help in i n f e r i n g r e l a t i o n s h i p s between p a i r s of these v a r i a b l e s . Pearson Product Moment C o r r e l a t i o n c a l c u l a t e s a c o r r e l a t i o n c o e f f i c i e n t and i t s a s s o c i a t e d l e v e l of s i g n i f i c a n c e . A l l c o r r e l a t i o n s whose p value was greater than 0.025 were r e j e c t e d as being i n s i g n i f i c a n t . Results of these c o r r e l a t i o n s are summarized in Appendix F.3. The product moment c o r r e l a t i o n c o e f f i c i e n t (r) i s used to 94 e x p l a i n the f r a c t i o n of v a r i a n c e of one v a r i a b l e by another v a r i a b l e . A high c o r r e l a t i o n c o e f f i c i e n t < 1.0000 i n f e r s a gre a t e r commonality between v a r i a b l e s than a lower one. A high negative c o r r e l a t i o n c o e f f i c i e n t > -1.0000 expresses a l a r g e negative e f f e c t one v a r i a b l e has over another ( i e , an inc r e a s e i n one v a r i a b l e r e s u l t s , i n a decrease of a n o t h e r ) . 4.6.3. KOLMOGOROV-SMIRNOV GOODNESS OF FIT TEST T h i s method i s a non-parametric t e s t to determine whether or not each v a r i a b l e i s normally d i s t r i b u t e d . T e s t s were run on separate and then combined w e l l s to check f o r n o r m a l i t y . T h i s t e s t was e s p e c i a l l y important f o r m u l t i p l e r e g r e s s i o n , which r e q u i r e s normally d i s t r i b u t e d data f o r a c c u r a t e r e s u l t s . ' A l l v a r i a b l e s i n separate, w e l l t e s t s were found to be normal with non-normality o c c u r r i n g d u r i n g combined w e l l t e s t s f o r some v a r i a b l e s . Non-normal v a r i a b l e s were d i s c a r d e d from f u r t h e r a n a l y s i s i n m u l t i p l e r e g r e s s i o n . In the K-S t e s t , a l l v a r i a b l e s below the p value of 0.05 were c o n s i d e r e d non-normal. R e s u l t s of these t e s t s are l i s t e d i n Appendix F.2. 4.6.4. MULTIPLE REGRESSION ANALYSIS In an attempt to p r e d i c t NH^-N gas and CH^ % from a v a i l a b l e data, m u l t i p l e r e g r e s s i o n was used. The form of the m u l t i p l e r e g r e s s i o n equation used i s below: Y = A + B.X, + B 0 X 0 + B,X- + .... B X v 1 1 2 2 3 3 n n Where Y i s the dependent v a r i a b l e A i s the Y - i n t e r c e p t (or constant) B n i s the p a r t i a l r e g r e s s i o n c o e f f i c i e n t X n i s the independent v a r i a b l e In t h i s equation i t i s shown that the l a r g e r the p a r t i a l 95 r e g r e s s i o n c o e f f i c i e n t , the more i n f l u e n c e i t s c o r r e s p o n d i n g , independent v a r i a b l e has on e s t i m a t i n g or p r e d i c t i n g the dependent v a r i a b l e . Stepwise r e g r e s s i o n was used in t h i s a n a l y s i s . The f i r s t step i n t h i s form of r e g r e s s i o n i s f o r the independent v a r i a b l e s to pass a t o l e r a n c e t e s t before e n t e r i n g the e q uation. The t o l e r a n c e t e s t i s the p r o p o r t i o n of the v a r i a b l e ' s v a r i a n c e not accounted f o r by; other independent v a r i a b l e s i n the equation. The d e f a u l t t o l e r a n c e of 0.010 was used. A f t e r p a s s i n g the t o l e r a n c e t e s t , the independent v a r i a b l e with the lowest p r o b a b i l i t y of F value i s entered i n t o the equation. I f a v a r i a b l e has an F that exceeds Pout (set at 0.010), i t i s removed from the equation and another v a r i a b l e not i n the equation i s t e s t e d . T h i s i t e r a t i v e method proceeds u n t i l no v a r i a b l e s not i n the equation are e l i g i b l e f o r entry (SPSS:X Users Manual, 1983). In a d d i t i o n to r e g r e s s i o n equation s t a t i s t i c s , s t a t i s t i c a l a n a l y s i s was done on the r e s i d u a l e r r o r of the equation. The r e s i d u a l a n a l y s i s was h e l p f u l i n determining the v i a b i l i t y of the r e s u l t a n t r e g r e s s i o n e q uation. T h i s was done by i n s p e c t i o n of the normal p r o b a b i l i t y and r e s i d u a l s c a t t e r p l o t s . I f any e x c e s s i v e n o n - l i n e a r i t y was found, the equation was c o n s i d e r e d suspect. 96 CHAPTER 5 5. RESULTS AND DISCUSSION 5.1. AMMONIA GAS ANALYTICAL TECHNIQUE 5.1.1. PROBLEMS ENCOUNTERED ON AUTOANALYZER Other than the problems a l r e a d y d i s c u s s e d concerning the f i e l d sampling technique, there were, a number of problems that arose d u r i n g the l a b o r a t o r y a n a l y s i s of NH^-N gas. These concerns or problems are l i s t e d below: A. S e n s i t i v i t y - Because of low standard c o n c e n t r a t i o n s of down to 0.05 mg/L, the gain on the instrument was i n c r e a s e d from the normal 200 to 500. T h i s had the e f f e c t of i n c r e a s i n g the s e n s i t i v i t y , but a l s o i n c r e a s e d s i g n a l n o i s e . B. B a s e l i n e wandering - Blanks were added to the sample t r a i n , every 5 or 6 samples to l o c a t e b a s e l i n e d r i f t . C. To h o p e f u l l y i n t e n s i f y the indophenol blue even f u r t h e r , 0.5 % potassium f e r r o c y a n a t e was added i n p l a c e of Na-n i t r o p r u s s i d e . The r e s u l t s however, only i n c r e a s e d s i g n a l n o i s e . D. Because my gain s e t t i n g s and standards were d i f f e r e n t from other l a b p r o j e c t s using the auto a n a l y z e r , my samples were run at the end of the day. T h i s l a t e day a n a l y s i s seemed to cause ; problems from,possible aged reagents and a \" t i r e d \" s i g n a l response. However, t e s t s comparing day-old and f r e s h l y made up phenate showed no change i n s i g n a l response. F l u s h i n g of the au t o n a l y z e r with d i s t i l l e d water before my sample a n a l y s i s was always done. 97 E. Suppressed S i g n a l Response - Concern f o r a suppressed s i g n a l response from the b o r i c a c i d standards and samples was layed to r e s t when standards of b o r i c acid-NH^-N and d i s t i l l e d water-NH^-N were run s i d e by s i d e . Accompanying the b o r i c a c i d was two other a c i d s used commonly i n ammonia a b s o r p t i o n , 0.1N HgSO'^-and o x a l i c a c i d . The comparison of s i g n a l responses are shown i n F i g u r e 5.1. D i r e c t i n s p e c t i o n of the four standards i n d i c a t e about an equal s i g n a l response when s u b t r a c t e d from t h e i r blank response. A t a b l e of % s i g n a l response i s shown below: TABLE 5.1 - R e s u l t s of S i g n a l Response Comparison Standard (mg/L) Wa t e r B o r i c H 2 S 0 4 O x a l i c 1 .0 36.7 38.5 39.0 38.3 0.5 17.7 21.5 21.0 20.2 0.2 12.8 8.5 8.2 8.1 0.1 4.6 4.5 2.7 4.0 F. Temperature and pH e f f e c t s -- These e f f e c t s were not i n v e s t i g a t e d , . b u t s t u d i e s from other i n v e s t i g a t o r s i s worth mentioning. The pH f o r optimal c o l o r was found to be from 11.3 to 11.7 (Scheimer, 1976). Because of the presence of a weak a c i d , i t i s h i g h l y d o u b t f u l that t h i s pH was ever reached i n the automated a n a l y s i s . However, no decrease in s i g n a l response i s found when.compared to the d i s t i l l e d water, so pH e f f e c t s may not make a d i f f e r e n c e . Stewart (1985) on the other hand, looked at temperature responses and found that the i n i t i a l temperature at 98 10 TO -2^ B l a n k ~=-^ 0.1 mg/L 0.2 mg/L ! OXALIC ACID 0.5 mg/L j . 1.0 mg/L SO 3 B l a n k - \" i ° : L m g / L 6.2 mg/L 0.1 N SULFURIC ACID: S^r-i 0 . 5 mg/L 1.0 mg/L i \"Blank ; 0.1 mg/L 13. 0.2 mg/L BORIC ACID . 6 0 • ;j] - 0 . 5 mg/L\" .j :1 . 0 mg/L DISTILLED WATER 7:0 j l . O mg/L Comparison o f R e c o r d e r S i g n a l s 70 TECHNICON AUTOANALYZER - j — G a i n 5 00 ' j No EDTA j F e b u r a r y 24, 1988 80 -I 30 FIGURE 5.1 - Comparison o f S i g n a l Responses From S t a n d a r d s o f Four S o l u t i o n s 99 reagent mixing was found to. determine the f i n a l c o l o r absorbance of the s o l u t i o n and any f u r t h e r i n c r e a s e i n temp. (50°C) only c a t a l y z e s the time to reach maximum absorbance. T h i s i s i n t e r e s t i n g , because mixing of c h i l l e d samples and room temperature standards c o u l d r e s u l t i n v a r i a b i l i t y of s i g n a l response. 5.1.2. INTERFERENCES A f t e r p r e l i m i n a r y a n a l y s i s of data showed NH^-N values lower than expected, an i n v e s t i g a t i o n was i n i t i a t e d to determine i f there i s any negative i n t e r f e r e n c e s i n the a n a l y t i c a l technique. P o t e n t i a l negative i n t e r f e r e n c e s are l i s t e d below i n po i n t form: 1. L a n d f i l l gas compounds c o u l d cause a decrease i n absorbance of NH^-N i n t o the b o r i c a c i d s o l u t i o n by a c t i n g as a c a r r i e r or complexer of the ammonia gas. T h i s e f f e c t c o u l d r e s u l t i n an recovery e f f i c i e n c y lower than estimated. The main cause to t h i s i s aqueous carbon d i o x i d e , which can c o v a l e n t l y bond with NH^ to form carbamic a c i d NH^'CC^. Th i s carbamic a c i d has been mentioned to be q u i t e v o l a t i l e (Hales and Drewes, 1982) and c o u l d c a r r y s u b s t a n t i a l amounts of NH^ from s o l u t i o n and out of the bubbler. T h i s i s e s p e c i a l l y t r u e where C0 2 c a n e x c e e d 45 % by volume i n l a n d f i l l , gas. More work would have to be done to s u b s t a n t i a t e t h i s c l a i m . 2. Another p o s s i b l e negative i n t e r f e r e n c e c o u l d r e s u l t from s o l u b l e gas components a f f e c t i n g indophenol blue c o l o r development i n the au t o a n a l y z e r . D e t a i l e d i n v e s t i g a t i o n s have been done on t h i s problem by B o l l e t e r (1961), Scheiner (1976) and 100 Ngo et a l . (1981) f o r other chemical a p p l i c a t i o n s on the a u t o a n a l y z e r . S o l u b l e and v o l a t i l e compounds that are u s u a l l y i n l a n d f i l l gas that c o u l d depress the c o l o r formation i n c l u d e the f o l l o w i n g : compounds with an amino f u n c t i o n a l group such as amines, hydrogen s u l f i d e and t h i o l group compounds and l a s t l y , carbon d i o x i d e . Amines are a common decomposition product of protenaceous matter and c o u l d be adsorbed i n t o b o r i c a c i d a t sub-ppm c o n c e n t r a t i o n s . A more l i k e l y suspect however, f o r causing odor suppression are the s o l u b l e s u l f u r group compounds. E s p e c i a l l y apparent i s H 2S, which has been det e c t e d at up to 1000 ppm i n Richmond l a n d f i l l gas. Both t h i o l compounds and H 2S are s t r o n g reducers that Ngo et a l . (1982) suggests c o u l d d e p l e t e the c o n c e n t r a t i o n of the strong o x i d i z e r h y p o c h l o r i t e , which i s r e q u i r e d f o r the formation of indophenol b l u e . K o r o l e f f (1970) concludes from h i s study on sludge a n a l y s i s that t o t a l s u f i d e s can be present i n up to 2 mg/L i n a sample without causing i n t e r f e r e n c e . If t o t a l s u l f i d e s are i n ppm c o n c e n t r a t i o n s i n l a n d f i l l gas, what f r a c t i o n of t h i s i s going to be converted to s u l f a t e s by o x i d a t i o n from sample h a n d l i n g and more l i k e l y , from oxygen found w i t h i n the l a n d f i l l gas? U n f o r t u n a t e l y , t h i s study d i d not attempt to determine s u l f a t e c o n c e n t r a t i o n s i n samples before and a f t e r sampling to see i f there i s any s u b s t a n t i a l d i f f e r e n c e . In an attempt to r i d the sample from t h i o l reducers and H 2S, two t e s t s were attempted on Richmond L a n d f i l l samples. F i r s t , p r e - d i s t i l l a t i o n was performed on samples that were trapped by 101 b o r i c a c i d . The r e s u l t s of t h i s t e s t showed no in c r e a s e i n s i g n a l response over the u n d i s t i l l e d samples. The second t e s t i n v o l v e d adding H 2 0 2 d i r e c t l y to samples before a u t o a n a l y s i s to o x i d i z e any reducing compounds. T h i s t e s t was u n s u c e s s f u l , because i t caused i n c r e a s e d c o l o r i n t e r f e r e n c e i n the sample a f t e r reagents were added. A l a s t - d i t c h e f f o r t to determine i f negative i n t e r f e r e n c e s were apparent i n samples was the running of standard a d d i t i o n t e s t s . The samples run were from F1 and F3 Matsqui, and D9 and D.55 Richmond. The r e s u l t a n t c o n c e n t r a t i o n s and t h e i r d i f f e r e n c e s are shown below i n Table 5.2. TABLE 5.2 - R e s u l t s of Standard A d d i t i o n T e s t s Well Measured (mg/L) : Std. A d d i t i o n % D i f f . D9 Richmond 0.500 0.500 0.0 D.55 Richmond 0.200 0.250 + 25.0 F1 Matsqui 0.095 0.1 25 + 31 .0 F3 Matsqui 0.113 0.125 + 11.0 .. In s p e c t i o n of the r e s u l t s do i n d i c a t e a depressed c o n c e n t r a t i o n i n some of the samples, which would be common i f there were negative i n t e r f e r e n c e s . However, these r e s u l t s should be t r e a t e d with c a u t i o n s i n c e more standard a d d i t i o n work needs to be done. T h i s d i f f e r e n c e i n c o n c e n t r a t i o n c o u l d a l s o be due to sample v a r i a n c e . 102 5.1.3. DETECTION LIMIT The d e t e c t i o n l i m i t of t h i s technique was found to be 0.03 mg/L. T h i s compares f a v o r a b l y to Dawson (1978) and NRC (1979), who mention d e t e c t i o n l i m i t s of 0.02 and 0.01 mg/L. A sample c o n c e n t r a t i o n of 0.03 mg/L i s about 12 ug/m (9 ppb) of NH3-N when the t o t a l gas volume i s around 175 l i t e r s . So i n summary, t h i s method d e t e c t s NH^-N c o n c e n t r a t i o n s g e n e r a l l y g r e a t e r than 10 ug/m3. 5.1.4. PRECISION Test s on 0.2 and 0.5 mg/L standards i n d i c a t e a r e l a t i v e standard d e v i a t i o n of 2.0 and 1.5 % r e s p e c t i v e l y for. 1.1 samples each. T h i s compares f a v o r a b l y with values of 0.5, 1.0 and 2.0 % mentioned i n Standard Methods, 16th E d i t i o n , Scheiner (1976) and O'Brien and F i o r e (1962) r e s p e c t i v e l y . R e p r o d u c i b i l i t y was not as great i n the l i m i t e d number, of samples t e s t e d . R e l a t i v e e r r o r s ranged from 4.5 to 8.5 % i n these samples. Accuracy of the technique was not attempted, s i n c e a l l samples were at too low a c o n c e n t r a t i o n f o r comparison with the d i s t i l l a t i o n - t i . t r a t i o n t echnique. Comparison with an i o n -s p e c i f i c e l e c t r o d e was a l s o r u l e d out because of que s t i o n s of accuracy concerning the e l e c t r o d e . One comparison has been made by Scheiner (1976) of the indophenol method and d i s t i l l a t i o n . R e s u l t s from t h i s paper i n d i c a t e a r e l a t i v e e r r o r of 5.2 % at 2 mg/L, which was the lowest c o n c e n t r a t i o n t e s t e d . 103 5.1.5. RECOVERY EFFICIENCY . O r i g i n a l l y when t h i s study began, I assumed that the bubbler technique would c o l l e c t NH^-N i n q u a n t i t a t i v e form (100 % c o l l e c t ion e f f i c i e n c y ) . However, a f t e r a n a l y z i n g the data, t e s t s were run to c a l c u l a t e a recovery r a t i o that c o u l d be a p p l i e d to the measured NHg-N to get a more accurate c o r r e c t e d c o n c e n t r a t i o n . Determining a recovery r a t i o became a more d i f f i c u l t task than p r e v i o u s l y expected. The f i r s t attempt i n v o l v e d i n j e c t i o n of small volumes of \"pure\" ammonia gas i n t o a l a r g e garbage bag that was f i l l e d with a i r up to 180 l i t e r s . The ammonia \"standard\" was then pumped through the bubbler s i m u l a t i n g f i e l d c o n d i t i o n s . These i n j e c t i o n s v a r i e d from about 25 to 100 uL of ammonia, which i s e q u i v a l e n t to 43 to, 172 ppm of ammonia. High ammonia amounts were used to See i f t h i s technique c o u l d be a p p l i e d i n determining recovery e f f i c i e n c y . However, the r e s u l t s were d i s a p p o i n t i n g , with very l i t t l e i f any ammonia detected.by the a u t o a n a l y z e r . The problem with t h i s technique seemed to . r e s u l t from how the ammonia gas i s sampled from the l e c t u r e c y l i n d e r t hat contained pure ammonia. Because, of no d i r e c t sample path i n t o the l e c t u r e c y l i n d e r , the gas had to f i r s t be s t o r e d i n t o a sample v i a l equipped with a rubber sample p o r t , then withdrawn from the sample v i a l by the s y r i n g e . T h i s was then d i r e c t l y i n j e c t e d i n t o the f i l l i n g garbage bag. The e r r o r s seem to r e s u l t i n not enough f l u s h i n g of the sample v i a l to get pure ammonia gas, or c o u l d be due to d i f f u s i o n of ammonia from 104 the garbage bag i n t o the l a b a i r before going through the bubbler to be absorbed. The next attempt with prolonged f l u s h i n g of gas through the sample v i a l d i d not improve the r e s u l t s . Two samples of 100 uL i n j e c t i o n d i d i n d i c a t e an u n c e r t a i n recovery e f f i c i e n c y of around 10 % at flows of 11.5 L/min. The l a s t attempt to determine a recovery e f f i c i e n c y was to go in a d i f f e r e n t d i r e c t i o n than b e f o r e . The technique used at t h i s time was to sample the f i l t e r e d a i r from the l a b o r a t o r y a i r l i n e s , s i n c e blanks were found to c o n t a i n enough ammonia (100 ug/m ) f o r a n a l y t i c a l d e t e c t i o n . The apparatus used i n t h i s t e s t had three bubblers i n s e r i e s with the gas p a s s i n g through each one. Each bubbler had the usual volume of 70 mLs of b o r i c a c i d , and a i r flow was v a r i e d from 2.1 to 11.5 L/min. T h i s type of apparatus was f i r s t used by O k i t a and Kanamori (1971) t e s t i n g the c o l l e c t i o n e f f i c i e n c y of g l a s s impingers i n a 0.1 N HjSO^ s o l u t i o n at a flow rate of 1.5 L/min. T h e i r ammonia standard . was r e p o r t e d to be 30 ppb.. T h e i r recovery e f f i c i e n c y f o r the f i r s t impinger averaged about 50 %. My r e s u l t s are summarized below in Table 5.3 f o r the three flow r a t e s . The raw data i s l i s t e d i n Appendix A.3. Recovery e f f i c i e n c y f o r the normal 6.0 L/min flow i s estimated at around 50 %. T h i s \" s a f e \" e f f i c i e n c y was estimated by assuming a very modest 30 % recovery e f f i c i e n c y i n the t h i r d bubbler and t a k i n g i n t o account, one, the standard d e v i a t i o n of these r e s u l t s , two, the decreased r e c o v e r i e s i n f i e l d c o n d i t i o n s and t h r e e , many of 105 the NH^-N gas values are much l e s s than the ambient a i r NH^-N. c o n c e n t r a t i o n s used i n t h i s experiment. TABLE ! 5.3 - R e s u l t s of Recovery E f f i c i e n c y T e s t s Flow . Mean Con c e n t r a t i o n in Escape From Recov. \"Safe\" (L/min) each bubbler (ug/M 3) 3rd (ug/M J) E f f , , E f f . 1 2 3 6.0 1 07. 0 28.4 22.9 16.0 6 1 . 4 % 50 % 10.5 . 89. 8 38.5 24.2 16.9 53.0 % 45 % 2.1 1 40. 3 36.0 58. 1 40.7 \"51.0 % 45 % I n t e r e s t i n g l y enough, the other two flow r a t e s show a l e s s e r recovery e f f i c i e n c y than the 6.0 L/min. My assumptions were that recovery e f f i c i e n c y should be. g r e a t e r i n lower flows, but t h i s i s not the case. T h i s was a l s o shown to be the case by Okit a and Kanamori (1971) using 0.02 N s u l f u r i c a c i d and 1.5 L/min flow. In c o n t r a s t , Morgan, Golden and Tabor (1967) i n d i c a t e almost 100 % recovery e f f i c i e n c y from a bubbler s o l u t i o n c o n t a i n i n g 0.05 N s u l f u r i c a c i d and 0.5 L/min flow. The high flow r a t e of 10.5 L/min g i v e s approximately the same recovery e f f i c i e n c y as the low flow r a t e . The r e s u l t s i n d i c a t e an e f f i c i e n c y of no gr e a t e r than 50 % and more l i k e 45 %. These r e s u l t s concur with the high flow e f f i c i e n c i e s measured by Kawamura and Sakurai (1966), who c a l c u l a t e d e f f i c i e n c y values of 0, 20 and 51 % f o r 0.02 s u l f u r i c a c i d s o l u t i o n and 15 L/min flow ( i n O k i t a and Kanamori, 1971). In s p i t e of the a n a l y t i c a l u n c e r t a i n t y , t h i s 50 % recovery 1 06 e f f i c i e n c y seems to be r e p r e s e n t a t i v e of the kind of recovery t h i s sample technique gets i n a c t u a l f i e l d c o n d i t i o n s . 5.2. TEMPORAL AND SPATIAL VARIATION OF DATA 5.2.1. VARIATION IN COLLECTED DATA As mentioned in Chapter 4, the r e s u l t s f o r a l l . the b a s i c data parameters are l i s t e d i n Appendix D. I n s p e c t i o n of the s t a t i s t i c a l r e s u l t s on each parameter ( i e , min., max., % C.V..) i n d i c a t e some i n t e r e s t i n g t r e n d s . For i n s t a n c e , i n s p e c t i o n of the C.V. i n d i c a t e s i n most i n s t a n c e s , the v a r i a b i l i t y was g r e a t e s t i n NH3~N gas and s t a t i c gas flow, while pH, barometric pressure and l e a c h a t e temp, e x h i b i t the lowest sample v a r i a n c e . 5.2.2. NON-METAL LEACHATE CONSTITUENTS A n a l y s i s of non-metal l e a c h a t e c o n s t i t u e n t s from gas e x t r a c t i o n w e l l s was done twice d u r i n g the study i n an attempt t o show temporal changes and r e l a t i v e d i f f e r e n c e s i n leachate s t r e n g t h between each l a n d f i l l . The r e s u l t s comparing the September and January samples are presented c o n c u r r e n t l y i n Tables 5.4 to 5.7. In g e n e r a l , leachate s t r e n g t h was h i g h e s t i n the younger l a n d f i l l s and lowest i n the o l d e r f i l l , S t r i d e Ave.. Chemical oxygen demand (COD) i s one c o n s t i t u e n t that i n d i c a t e s t h i s r e l a t i o n s h i p . In Matsqui and Richmond l a n d f i l l s , v a r i o u s w e l l s i n d i c a t e a f a i r l y high COD (average over 1000 mg/L) whereas S t r i d e Ave. averages l e s s than 150 mg/L. T h i s r e f l e c t s S t r i d e Avenue's much ol d e r f i l l age where most of the s o l u b l e organic m a t e r i a l i s probably s t a b l e humic and f u l v i c a c i d s . In c o n t r a s t 1 07 to COD's, most of the r e s u l t s i n d i c a t e TVA v a l u e s i n S t r i d e Ave. to be comparable to the much younger lea c h a t e of Richmond l a n d f i l l . TVA i s c o n s i d e r e d the most r e a d i l y biodegradable s u b s t r a t e f o r methanogen u t i l i z a t i o n and i s u s u a l l y more abundant i n young l a n d f i l l s . T h i s anomalous s i m i l a r i t y i n TVA values may be a r e s u l t of the much higher methane p r o d u c t i o n r a t e s e x h i b i t e d by Richmond l a n d f i l l , where any a v a i l a b l e TVA i n the l e a c h a t e i s consumed. O v e r a l l , the h i g h e s t TVA amounts were from Matsqui, which was expected s i n c e the s t r o n g e s t l e a c h a t e odors u s u a l l y emanated from those samples. Matsqui l a n d f i l l a l s o e x h i b i t s very high NH^-N l e a c h a t e c o n c e n t r a t i o n s i n two of the w e l l s (F1 and F5) and c o u l d be i n d i c a t i v e of the high p r o t e i n i n animal waste that was dumped at t h i s l a n d f i l l . A l l three younger l a n d f i l l s e x h i b i t high p r o p o r t i o n s of TOC, which may.be a r e s u l t a n t of the organic l i q u i d waste and sludges r e p o r t e d to be dumped in these l a n d f i l l s over t h e i r l i f e t i m e . An i n t e r e s t i n g p o i n t to a l l of t h i s a n a l y s i s i s that one would assume a f t e r n o t i c i n g the r e l a t i v e low v a l u e s of TOC and COD from S t r i d e Ave that t h i s l a n d f i l l would e x h i b i t low CH^ percentages. However, t h i s i s not always the case i f one n o t i c e s CH 4 % v a l u e s i n Appendix D f o r w e l l s F2, F3, F7, F8 where CH4 % g e n e r a l l y exceeds 40 %. T h i s might be a r e s u l t a n t of the r e l a t i v e high TVA values a l r e a d y d i s c u s s e d or because d u r i n g the study p e r i o d t h i s e x t r a c t i o n w e l l system was never o p e r a t i o n a l . In most i n s t a n c e s , temporal v a r i a t i o n between samples taken 108 - Hatsqui Landfill -Uell No. DATE pH Speci fic Conduct, Alt. NH3-N <«g/L) COD (•g/L 02) TC IOC TVA Total Solids Volatile Solids 2 Vol. Residue Fl Feb. 88 6.34 21,200 7500 2669.3 35,100 16,300 16,225 21,736 30,350 18,290 60.3 F2 F2 Sept. 87 Feb. 88 7.40 6.29 3640 1083 1254 340 252.0 70.6 1716 2344 480 1135 295 1035 208 3555 1465 41.2 F3 Feb. 68 6.60 1660 375 142.8 712 805 660 201 3710 1060 28.6 F5 F5 Sept. 87 Feb. 88 6.82 6.17 21,913 4405 6650 1120 1881.6 300.6 30,400 5634 10,900 . 2240 10,637 2065 15,390 2784 28,635 4530 18,575 2440 64.9 53.9 F8 Feb. 88 5.79 439 153 1.4 -- -- 12 500 100 20.0 - Stride Ave. Landfill -Uell No. DATE pH Speci fic Conduct. AIL NH3-N (•g/L) COD (»g/L 02) TC TOC TVA Total Solids Volatile Solids I Vol. Residue F2 F2 Sept. 87 Feb. 88 6.46 6.26 1182 1270 • 577 594 1.8 4.1 200 60 178 240 N.D. 30 40 112 781 1410 165 685 21.1 48.6 F3 F3 Sept. 87 Feb. 88 6.38 6.14 999 977 472 . 459 2.9 7.1 64 112 83 217 N.D. 71 60 86 785 985 225 380 23.7 38.6 F6 Feb. 88 5.88 B39 333 15.4 124 147 26 255 1070 690 64.5 F7 F7 Sept. 87 Feb. 88 6.25 6.31 1089 1081 495 504 15.4 9.5 128 248 105 189 39 167 70 251 1256 1490 308 390 24.5 26.2 F8 Feb. 88 5.86 763 351 2.8 92 120 21 237 860 250 29.1 108 Sept. 87 • 6.04 1377 609 1.2 160 120 N.D. 89 1178 387 32.8 Specific Conductance in uiho/cn Alkalinity in og/L as CaC03 TC = Total Carbon (>g/L as 0 TOC = Total Organic Carbon (ig/L as C) TVA Total Volatile Acids (ig/L as Acetic Acid) TABLES' 5.4 & 5.5 - NON-METAL LEACHATE CONSTITUENTS IN MATSQUI AND STRIDE AVE. LANDFILLS 109 Richiond Landfill -Utll No. . DATE pH Speci fic Alk. NH3-N COD TC TOC TVA Total Volatile I Vol. Conduct. («g/U («g/L 02) Solids Solids Residue 88 Sept. 87 $.40 3301 1215 122.1 1137 335 t46 452. 2429 1190 49.0 B8 Feb. 88 6.16 1755 1719 58.2 237 350 20 128 1105 490 44.4 D9 Sept. 87 6.80 8347 2320 378.0 1217 1230 495 348 4766 1410 29.6 09 Feb. 88 6.81 7493 390 425.6 1473 1340 470 360 4300 1365 31.8 C6 Sept. 87 6.42 2732 920 23.5 1321 290 105 452 2142 1473 68.8 C6 Feb. 88 6.17 2177 555 16.8 1175 670 320 592 1980 800 40.4 G7 Sept. 87 6.48 3426 1340 73.9 342 305 109 • 191 2291 843 36.8 67 Feb. 88 6.11 1835 525 25.8 157 - 360 N.D. 80 1280 270 31.1 D.55 Sept. 87 6.74 4243 1760 113.1 653 330 70 209 3030 1015 33.5 D.55 Feb. 88 6.40 3465 1260 101.9 410 730 45 108* '• 2345 830 35.4 8.53 Sept. 87 6.58 3432 1420 121.0 453 315 108 139 2252 652 29.0 B.53 Feb. 88 6.22 1394 360 22.4 76 205 10 35 770 395 51.3 ===s = t \" \" = = \" = = ====-===; ========= ========= ======== -__ Prenier Street Landfill Veil No. DATE pH Specific Conduct. Alk. NH3-N COD TC (•g/L) (tg/L 02) TOC TVA Total Volatile I Vol; Solids Solids Residue PI Sept. 87 PI Feb. 8B 6.72 6.67 6683 5915 1840 1320 213.9 254.2 690 487 815 ' 720 350 130 166 100 3965 3860 885 805 22.3 20.9 P2 Sept. 87 P2 Feb. 88 6.74 6.75 6411 5459 1820 1200 221.8 231.8 444 447 768 670 108 95 145 120 3432 3065 610 26.5 19.9 Specific Conductance in uiho/ci Alkalinity in rig/I as CaC03 TC = Total Carbon (»g/L as 0 TOC = Total Organic Carbon (»g/L as C) TVA = Total Volatile Acids (ig/L as Acetic Acid) TABLES 5.6 & 5.7 - NON-METAL LEACHATE CONSTITUENTS IN RICHMOND AND PREMIER ST. LANDFILLS 110 i n September and then i n January i s f a i r l y low. The w e l l s that show l a r g e decreases i n c o n c e n t r a t i o n s are mostly due to l a r g e volume d i l u t i o n from e x c e s s i v e r a i n f a l l i n f i l t r a t i o n . T h i s i s e s p e c i a l l y apparent i n Richmond l a n d f i l l w e l l s and F5 Matsqui where f r e s h water has entered the w e l l above the leac h a t e due to a crack i n the c a s i n g caused by l a n d f i l l subsidence. In Richmond, high volumes of r a i n f a l l have d i l u t e d leachate because of the l a n d f i l l ' s porous sand cover coupled with an alr e a d y high water tables Some w e l l s such as F2 Matsqui, F-2 and F7 S t r i d e i n d i c a t e i n c r e a s e d l e a c h a t e s t r e n g t h , which i s most l i k e l y due to p r e c i p i t a t i o n i n f i l t r a t i o n f l u s h i n g out o r g a n i c s from the unsaturated zone which are then d e p o s i t e d i n t o the le a c h a t e . 5.2.3. PRECIPITATION Comparison of weekly p r e c i p i t a t i o n from the three weather s t a t i o n s i s shown below i n F i g u r e 5.2. The weekly p r e c i p i t a t i o n data i s presented i n Appendix C. In g e n e r a l , the wettest weather s t a t i o n of the three i s Vancouver Harbour, which r e c e i v e s over 1600 mm p r e c i p i t a t i o n per year. The d r y e s t s t a t i o n is.Vancouver I n t e r n a t i o n a l that averages j u s t over 1100 mm/year. In s p e c t i o n of F i g u r e 5.2 i n d i c a t e s an unseasonably dry and m i l d autumn and mid-winter p e r i o d where minimal amounts of p r e c i p i t a t i o n o c c u r r e d . These p e r i o d i c dry p e r i o d s helped i n keeping cumulative p r e c i p i t a t i o n over 20 % below normal throughout the study p e r i o d . 111 FIGURE 5.2 - Comparison of Weekly P r e c i p i t a t i o n From Three Weather S t a t i o n s Note : Vancouver Harbor S t a t i o n was d i s c o n t i n u e d at end of March 200-150 100 E E c z: g I Q_ ( J L d cr Q_ 50-Ld Ld Legend zn AIRPORT EES HARBOR E D A B B 0 T S F 0 R D TIME in months The r e s u l t s d i s c u s s e d p r e v i o u s l y and ones presented l a t e r i n d i c a t e that excessive i n f i l t r a t i o n of t h i s p r e c i p i t a t i o n may cause the greatest changes i n leachate s t r e n g t h and gas production. Although an increase in moisture content has been found by many authors (see Chapter 2 - L i t . Review) to he l p gas production, t h i s study found the opposite when excessive p r e c i p i t a t i o n f e l l on the study areas. T h i s was e s p e c i a l l y evident a f t e r l a r g e p r e c i p i t a t i o n episodes. To strengthen t h i s observation, c o r r e l a t i o n a n a l y s i s ' u s u a l l y i n d i c a t e a strong negative r e l a t i o n s h i p between p r e c i p i t a t i o n and va r i o u s other parameters (See Appendix F.3). The main reason f o r t h i s negative 112 c o r r e l a t i o n i s probably e i t h e r from volume d i l u t i o n of l e a c h a t e or the p r e c i p i t a t i o n shock l o a d i n g the unsaturated zone m i c r o b i a l p o p u l a t i o n . T h i s has the e f f e c t of d e c r e a s i n g gas p r o d u c t i o n . One sample w e l l , P2 Premier S t . responded q u i t e a b r u p t l y with i n c r e a s e d p r e c i p i t a t i o n i n f i l t r a t i o n . R e s u l t s presented i n F i g u r e 5.3 i n d i c a t e CH^ % dropped very r a p i d l y from over 50 % to 5 % (See F i g u r e 5.4) i n l e s s than a month a f t e r a major p r e c i p i t a t i o n i n f l u x i n mid-November. The percent methane never recovered throughout the r e s t of the study p e r i o d . The c o n t r i b u t i o n of p r e c i p i t a t i o n i n d e c r e a s i n g the gas percentage at P2 Premier i s not c l e a r , s i n c e the w e l l i s on vacuum du r i n g the winter months. T h i s vacuum may cause the gas sample to be d i l u t e d with atmospheric a i r from a i r i n t r u s i o n . So these samples may be u n r e p r e s e n t a t i v e of the unsampled CH^ c o n c e n t r a t i o n deeper in the w e l l . Other w e l l s p l o t t e d i n F i g ' s 5.3, 5.5 and 5.6 do not i n d i c a t e a c c e l e r a t e d drops i n CH^ % but do e x h i b i t a general decrease throughout the study p e r i o d . In a d d i t i o n to a methane pr o d u c t i o n drop, C O 2 % changes were analyzed to see i f i n c r e a s e d p r e c i p i t a t i o n would r e s u l t i n d e c r e a s i n g C O 2 % r e l a t i v e to methane percent. The added p r e c i p . was g e n e r a l l y b e l i e v e d to r e s o l u b i l i z e a f r a c t i o n of the C 0 2 , t a k i n g i t out of the gas phase. R e s u l t s however, i n d i c a t e no profound r e l a t i o n s h i p between C 0 2 % and p r e c i p . , except i n F7 S t r i d e (See F i g . 5.6) where some drop in C 0 2 % i n Feburary-March may be due to t h i s or to a m i c r o b i a l l y mediated phenomenon. E z: o I Q_ o Ld Cd Q_ 113 FIG. 5.3-TEMPORAL VARIATION OF WEEKLY PRECIP. vs. GAS % G7 RICHMOND 150-i • , , - 6 0 - 5 0 - 4 0 I— ZZL i • i 111 O - 3 0 Q: Ld Q_ - 2 0 Ul < - 1 0 - 0 v ^ A A ^ , 3r & ^ ^ - 6 0 - 5 0 i - 4 0 i— z: Ld o - 3 0 DC Ld Q_ - 2 0 Ul < - 1 0 - 0 TIME in mon ths FIG. 5.4 -TEMPORAL VARIATION OF WEEKLY PRECIPITATION VS. NH3-N GAS, P2 PREMIER STREET 1 14 FIG. 5.5 TEMPORAL VARIATION OF WEEKLY PRECIP. vs. GAS % F3 MATSQUI 150-T £ E •125-c * — 100-iz o 1— 7 5 -pi i Q_ 5 0 -O LxJ 2 5 -Q_ 0-Legend A CH4 X C02 mo •ny~i J J -60 - 5 0 ^ - 4 0 NT LxJ o - 3 0 i . i LxJ Q_ -20 CO < -10 -0 •V ^ / V J /'O *< ^ c T ^ < ^ ^ ^ ^ ^ TIME in months F7 STRIDE 150-E 125-C 100-z o 7 5 -1— 1 K 5 0 -(J L J 2 5 -C£ Q_ 0-^ # # cf ^ <^ ^ ^ f # ^ TIME in months FIG. 5.6 -TEMPORAL VARIATION OF WEEKLY PRECIPITATION VS GAS, F7 STRIDE AVE. NH3-N 115 5.2.4. TEMPERATURE In a l l w e l l s , there was a g e n e r a l decrease i n gas and water temperature with the c o l d e r winter months. Temperature p r o f i l e s f o r four w e l l s are presented i n F i g s 5.7 through 5.10... In g e n e r a l , most gas temperature f l u c t u a t i o n s r e f l e c t a f l u c t u a t i o n i n ambient a i r temperature i n the more m i l d f a l l months preceeded by more divergence i n the winter months. T h i s d i f f e r e n c e i n winter months between gas and a i r temperature may be regulated,by the i n s u l a t i n g a b i l i t y of the l a n d f i l l . A l s o , p r e c i p i t a t i o n i n f i l t r a t i o n may h e l p i n d e p r e s s i n g gas temperatures even more. T h i s may be the case i n G7 Richmond (See F i g . 5.9) where the temperature range goes from 29 to 8°C. The other three deeper w e l l s l o c a t e d i n d i f f e r e n t l a n d f i l l s decrease to no lower than a \" t h r e s h o l d temperature\" of about 12°C. T h i s temperature c o u l d again be due to the b e t t e r i n s u l a t i n g c a p a c i t y and l e s s e r p r e c i p . i n f l u x at these l a n d f i l l s than i n Richmond. In c o n t r a s t to w e l l G7, some w e l l s l i k e D9 Richmond e x h i b i t very l i t t l e decrease i n lea c h a t e (Tw) and gas temperature (Tg) over the study p e r i o d . D9 Richmond temperatures were c o n s i s t e n t l y the h i g h e s t measured and ranged from a Tg of 32 - 16°C to a Tw of 28 - 23°C. The reason D9 Richmond may be r e l a t i v e l y . u n a f f e c t e d by p r e c i p i t a t i o n i n f i l t r a t i o n and c o l d e r a i r temperatures l i k e other Richmond w e l l s , c o u l d be due to a very e f f i c i e n t b i o l o g i c a l system that c r e a t e s l a r g e volumes of i n s u l a t i n g heat. The d i f f e r e n c e s between temperature ranges i n a l l the Richmond study, w e l l s give an i n d i c a t i o n of how much s p a t i a l h e t e r o g e n i t y can occur w i t h i n 116 the same l a n d f i l l . W ithin a l l the w e l l s s t u d i e d , the temperature ranges f o r gas, le a c h a t e and ambient a i r were 32 - 7°C, 28 - 7°C and 26 minus 3°C r e s p e c t i v e l y . The decrease in a i r and gas temperature i n d i c a t e an o v e r a l l mixed p a t t e r n of methane percentage f o r most of the w e l l s . In Richmond L a n d f i l l , the temperature drops d i d not seem to e f f e c t CH^ %, while i n S t r i d e Ave (F2 and F3), there are sometimes l a r g e decreases due to temperature drops. However, the e f f e c t that temperature drop i s not c e r t a i n because of the c o u p l i n g e f f e c t p r e c i p i t a t i o n i n f i l t r a t i o n may have in c o n t r o l l i n g both temperature and CH^ %. One o b s e r v a t i o n d i r e c t l y r e l a t e d to temperature was f r e e z i n g of the l a n d f i l l s u r f a c e during the c o l d winter p e r i o d s . T h i s was e s p e c i a l l y apparent at Matsqui l a n d f i l l where p r e c i p i t a t i o n i n f i l t r a t i o n c o u l d be i n h i b i t e d by the fro z e n s u r f a c e , which i n e f f e c t may have helped gas p r o d u c t i o n while! o f f s e t t i n g some d e t r i m e n t a l e f f e c t s caused by c o l d temperatures. 5.2.5. OXIDATION REDUCTION POTENTIAL Another parameter r e l a t e d t o p r e c i p i t a t i o n i n f i l t r a t i o n and c o u l d be very important i n c o n t r o l l i n g gas p r o d u c t i o n i s ORP. As a l r e a d y mentioned, methanogens r e q u i r e an Eh of -200 to -300 mV fo r proper growth and are very s e n s i t i v e to changes i n ORP. I n f i l t r a t i n g rainwater i n most cases has a p o s i t i v e Eh that may cause a shock to methanogenic b a c t e r i a hence, lowering gas p r o d u c t i o n r a t e s . U n f o r t u n a t e l y , t h i s i s one parameter that was 117 FIG. 5.7 -TEMPORAL CHANGES IN GAS AND AMBIENT TEMP. F2 MATSQUI TIME in m o n t h s FIG. 5.8 -TEMPORAL CHANGES IN GAS AND AMBIENT TEMP. F7 STRIDE AVE. CO o 2 : CL Ld I— if) < 118 FIG. 5 . 9 -TEMPORAL VARIATIONS IN GAS vs. AMBIENT TEMP. G7 RICHMOND 30-1 25 20 15 H 10 5-1 0 - 5 Gas Temp Air Temp p 3 0 - 2 5 - 2 0 IMP. -15 V— -10 EN1 - 5 AMBI TIME in m o n t h s P1 PREMIER St. 0 - 5 25 CO 13 20-*co Q) O z : 15-CL 10-Ld h-CO c < 5 -O 0-^ & c**^ ^ ^ TIME in m o n t h s FIG. 5.10 -TEMPORAL CHANGES IN GAS AND AMBIENT AIR TEMP PI PREMIER ST. 25 h20 . Q_ Ld M 5 h-10 Ld CQ - 5 < 0 119 not monitored because a downhole i n s i t u redox probe was not a v a i l a b l e at the time. 5.2.6. STATIC GAS FLOW A few authors (Thibodeaux et a l . , 1982 and Shen, 1981) have observed d u r i n g low barometric pressure p e r i o d s , an i n c r e a s e i n emission f l u x from covered l a n d f i l l s due to p r e s s u r e pumping from high pressure b u i l t up i n s i d e the l a n d f i l l . T h i s phenomenon was monitored throughout my study p e r i o d by comparing.barometric pressure with s t a t i c gas flow. My r e s u l t s i n d i c a t e no r e l a t i o n s h i p between the two parameters in not only the p l o t s (See F i g s 5.11 to 5.16) but a l s o i n the Pearson C o r r e l a t i o n a n a l y s i s . I f there i s a r e l a t i o n s h i p , one would observe a s i g n i f i c a n t negative c o r r e l a t i o n between gas flow and p r e s s u r e . I n s p e c t i o n of F i g s 5.14, 5.15 and 5.16 i n d i c a t e an unusual p a t t e r n i n Matsqui w e l l s where f a l l i n g pressure may be causing lower flow, which i s the d i r e c t o p posite of what should be found. The reason f o r t h i s anomaly may be due to l a n d f i l l microbe metabolism being s e n s i t i v e to changes i n barometric p r e s s u r e , or most l i k e l y , a decompression of the l a n d f i l l d u r i n g lower pressure regimes. The l a t t e r e f f e c t would cause lower i n t e r n a l l a n d f i l l p r e s s u r e s which, t r a n s l a t e s i n t o lower s t a t i c gas flows. The main reason why no low pressure pumping responses were observed i n these four l a n d f i l l s c o u l d r e s u l t from each : l a n d f i l l ' s cover c h a r a c t e r i s t i c s . L a n d f i l l s that have been observed to respond to barometric pressure f l u c t u a t i o n s have a w e l l c o n s t r u c t e d \" t i g h t \" c l a y cap that helps to b u i l d up i n t e r n a l 120 FIG. 5.11 \"E GAS FLOW vs BAROMETRIC PRESSURE B8 RICHMOND O _j Ld ^ ^ 0o^ ^ ^ ^ ^ ^ ^ TIME in m o n t h s FIG. 5.12 - GAS FLOW vs BAROMETRIC PRESSURE P2 PREMIER ST. 10-1 '< - 1 0 3 O z UJ Cxi - 1 0 2 ZD (/) CO Ld Cxi 0_ O - 1 0 1 cr: Ld o < - 1 0 0 CD 8-O —I 4 H Ld 2 -P r e s s u r e 0 J | —| n —T —| — | — | — 1 • ^ 4 ^ ^ <$> ^ <^ ^ ^ - 1 0 4 O 0_ -z. - 1 0 3 Ld or: CO CO L d - 1 0 2 Cxi 0_ c r r— - 101 Ld o or: < - 1 0 0 121 FIG. 5 . i 3 - GAS FLOW vs BAROMETRIC PRESSURE F8 STRIDE 20-1 ^ <$ ^ ^ <$> ^ TIME in m o n t h s FIG. 5 . i 4 - GAS FLOW VS. BAROMETRIC PRESSURE F2 MATSQUI 100 - 1 0 3 a Q_ LxJ or: - 1 0 2 ZD CO CO I I 1 LJU or: CL O -101 o r i Ld o CrT < - 1 0 0 P r e s s u r e 103 o Q_ o r r-102 3 CO CO LU o r Q_ o |-101 EE . i— Ld ZE O o r < 100 CQ 122 G. 5.15 200-1 GAS FLOW vs BAROMETRIC PRESSURE F3 MATSQUI 150 iooH 50H 0 H TIME in m o n t h s IG. 5 . i 6 - GAS FLOW vs. BAROMETRIC PRESSURE F4 MATSQUI -103 o Q_ Ld cr. -102 ZD CO CO Ld o: o -101 I 1 Ld o < -100 CD O CrT < 100 CD 123 • ' • . l a n d f i l l p r e s s u r e s , whereas, i n these four l a n d f i l l s , the caps were c o n s t r u c t e d of heterogeneous m a t e r i a l where i n t e r n a l l a n d f i l l pressure may be r e l i e v e d c o n t i n u o u s l y through the cover. Since barometric pressure f l u c t u a t i o n cannot e x p l a i n the changes i n s t a t i c ; l a n d f i l l gas flow, there must be other mechanisms behind t h i s n a t u r a l flow. I b e l i e v e these mechanisms are: 1. M i c r o b i a l a c t i v i t y - probably the most important mechanism f o r s t a t i c gas flow. I n t e r n a l l a n d f i l l p r essure b u i l t up through m i c r o b i a l gas p r o d u c t i o n causes c o n v e c t i o n flow towards the lower pressure . l a n d f i l l s u r f a c e . 2. Thermal flow - T h i s c o u l d become important d u r i n g the winter months when a warmer l a n d f i l l i n t e r i o r and c o o l e r l a n d f i l l s u r f a c e cause thermal c o n v e c t i o n c u r r e n t s to flow upward through the l a n d f i l l . 3. D i f f u s i o n flow - May become important where co n v e c t i o n flow i s minimal. 4. C e l l c o n s t r u c t i o n - The morphology of the c e l l and how i t i s c o n s t r u c t e d can i n f l u e n c e gas pressure b u i l d - u p and how t h i s p r essure i s r e l e a s e d . The f r a c t i o n of the s t a t i c flow caused by thermal c o n v e c t i o n i s probably s m a l l , but may have c o n t r i b u t e d s u b s t a n t i a l l y to the i n c r e a s e of w e l l flows of D9 and C6 i n Richmond (see Appendix 4) du r i n g the l a s t months of the study. The e f f e c t s of c e l l c o n s t r u c t i o n are probably c o n t r i b u t i n g g r e a t l y to the s p a t i a l v a r i a b i l i t y of gas flows i n each l a n d f i l l . Measurements of s t a t i c gas flows in t h i s study ranged from no d e t e c t i o n t o over 290 L/min. In most i n s t a n c e s , c e r t a i n w e l l s in Matsqui (F1, F2, F3, F4) and Richmond (D9 and C6) always r e g i s t e r e d the highest s t a t i c flows, while S t r i d e Ave and 1,24, Premier S t . w e l l s u s u a l l y r e g i s t e r e d lower flows. An i n t e r e s t i n g o b s e r v a t i o n to note was i n two sample p e r i o d s (Dec. 31st. and Mar. 3rd), flows were undetected i n a l l sample w e l l s at S t r i d e Ave. Why t h i s happened i s not known, s i n c e both p e r i o d s were not preceeded by heavy r a i n s or su b j e c t e d to u n s u a l l y h i g h barometric p r e s s u r e . In most i n s t a n c e s , c o r r e l a t i o n a n a l y s i s found no r e l a t i o n s h i p between i n c r e a s e d m i c r o b i a l a c t i v i t y ( i n t h i s case, i n c r e a s e d CH 4 %) and s t a t i c , gas flow. R's of the s i g n i f i c a n t c o r r e l a t i o n s were a l l l e s s than 0.5000. The w e l l with c o n t i n u a l high flows, C6 Richmond, d i d show a response of g r e a t e r CH^ % with i n c r e a s e d gas flow. To study how s t a t i c gas flow may change d u r i n g the day, flow measurements were done at F1 Matsqui on an h o u r l y b a s i s d u r i n g four sample p e r i o d s . The r e s u l t s of these measurements are presented i n F i g u r e 5.17. I n s p e c t i o n of F i g u r e 5.17 i n d i c a t e s a i n c r e a s e of gas flow from 10 A.M. to 3 P.M. with two of the r e s u l t s i n d i c a t i n g a steadying decrease i n flow a f t e r t h i s time. Sampling p e r i o d s were done on days of s l i g h t l y i n c r e a s i n g or ste a d y i n g barometric p r e s s u r e , so pressure pumping cannot be a -f a c t o r i n these r e s u l t s . These r e s u l t s may i n d i c a t e the p o t e n t i a l f o r d i u r n a l f l u c t u a t i o n s i n s t a t i c gas flow. Because Thibodeaux et a l . (1981) d i d detect a d i u r n a l f l u c t u a t i o n i n i n t e r n a l l a n d f i l l p r e s s u r e s , the above hypothesis may be t r u e , but needs more f i e l d work to s u b s t a n t i a t e t h i s c l a i m . 125 5.2.7. N 2/0 2 GAS RATIO The a n a l y s i s of gas percentage r e s u l t s uncovered something unusual concerning N 2/0 2 gas r a t i o s from some sample w e l l s . In most i n s t a n c e s , the N 2/0 2 r a t i o i s around 4.0, which i s common for normal a i r i n t r u s i o n , however, some w e l l s i n Matsqui and S t r i d e Ave e x h i b i t r a t i o s that sometimes exceed 20.0. For four of these w e l l s (F1, F3 Mats and F2, F7 S t r ) the temporal v a r i a t i o n of t h i s r a t i o i s presented i n F i g s 5.18 & 5.19. In s p e c t i o n of these f i g u r e s i n d i c a t e a l a r g e v a r i a b i l i t y of the r a t i o throughout time. One t h i n g to note i s the 0.0 r a t i o of F7 Str i n l a t e October. T h i s i s because a i r was not d e t e c t e d i n the sample by the gas p a r t i t i o n e r . N 2/0 2 r a t i o s f o r a l l the sample w e l l s are l i s t e d i n Appendix E. The higher p r o p o r t i o n of N 2 from the gas i n these w e l l s c o u l d be caused by three processes l i s t e d below: 1. There c o u l d be an i n c r e a s e of N 2 due to d e n i t r i f i c a t i o n . 2. Consumption of oxygen by i n o r g a n i c redox processes o p e r a t i n g w i t h i n the l a n d f i l l c o u l d occur. 3. Oxygen c o u l d a l s o be consumed by ae r o b i c microorganisms i n the l a n d f i l l . For #1 to be s u b s t a n t i a l , there would have to be s u f f i c i e n t source of n i t r a t e , which d e n i t r i f i e r s use as the t e r m i n a l e l e c t r o n acceptor f o r N 2 p r o d u c t i o n . The o x i d a t i o n of ammonia to n i t r a t e i s u n l i k e l y to occur i n an anaerobic l a n d f i l l environment s i n c e the n i t r i f i e r s are s t r i c t aerobes. 126 n o . 5 . i 7 . W E L L FLOW vs. HOURLY TIME F1 MATSQUI 90 20 H 1 1 1 r 1 1 1 9 10 11 12 13 14 15 16 TIME IN hours 127 FIG. 5.18 -LANDFILL GAS N2/02 RATIO vs TIME MATSQUI F1 andF2 & 4 & ^ 4> ^ & ^ TIME in m o n t h s STRIDE F2 and F7 TIME in m o n t h s FIG. 5.19 -LANDFILL GAS N2/02 RATIO VS. TIME STRIDE AVE. F2 AND F7 1 28 Mechanism #2 may occur i n . s u b s t a n t i a l amounts where reducing agents such as metals and s u l f i d e compounds c o u l d consume oxygen through redox processes,.hence causing a g r e a t e r b u i l d - u p of N 2 r e l a t i v e to 0 2. Mechanism #3 i s probably the most dominant sink of gaseous C>2 from l a n d f i l l gas. The consumption of 0 2 by ae r o b i c b a c t e r i a i n l a n d f i l l s i s g e n e r a l l y c o n s i d e r e d to be a short term process d u r i n g the e a r l y stages of a completed l a n d f i l l . However, there i s a c e r t a i n group of ae r o b i c b a c t e r i a c a l l e d Methanotrophs that can u t i l i z e the 0 2 as a t e r m i n a l e l e c t r o n acceptor while u t i l i z i n g methane gas as a growth s u b s t r a t e . C 0 2 i s then produced as a gaseous byproduct. The f o l l o w i n g equation from Large (1982) summarizes t h i s o x i d a t i o n of methane to C0 2 by methanotrophs: . CH 4 ---> CH3OH ---> H'CHO . > H'COOH ---> C0 2 In theory, these b a c t e r i a c o u l d s u r v i v e n i c e l y i n the upper l a n d f i l l environment where ample amounts of a i r i n t r u s i o n can occur due to oxygen d i f f u s i o n through the cover, or v i a l a n d f i l l gas pumping. For a more d e t a i l e d d i s c u s s i o n on methanotroph ecology and t h e i r r e l a t e d growth a c t i v i t y r e f e r to Wolfe and Higgi n s (1979) and Leak and Dalton (1986). In a d d i t i o n to consuming 0 2 and CH 4 f o r growth, methanotrophs can a l s o act as n i t r i f i e r s , o x i d i z i n g ammonia-n i t r o g e n to n i t r a t e much l i k e nitrosomonas and n i t r o b a c t e r do under normal o x i d i z i n g c o n d i t i o n s . So mechanism #3 can produce the source of n i t r a t e s r e q u i r e d f o r #1 to f u n c t i o n . T h i s 129 symbiotic r e l a t i o n s h i p produces even more N 2 to i n c r e a s e the N 2/0 2 r a t i o even f u r t h e r . U n f o r t u n a t e l y , the l e a c h a t e was not analyzed f o r n i t r a t e . T h e r e f o r e , given the r i g h t environmental c o n d i t i o n s , t h i s methane degrading group of b a c t e r i a may be c a using the anomalous N 2/0 2 gas r a t i o observed i n two of four l a n d f i l l s s t u d i e d . 5.3. VARIABLES THAT AFFECT METHANE GAS PCT. In a d d i t i o n to p r e c i p i t a t i o n , temperature and ORP a f f e c t i n g CH 4 %, other parameters such as C0 2 f l u x , i o n i c s t r e n g t h and gas flow can a l s o be c o n s i d e r e d a f a c t o r i n CH^ % f l u c t u a t i o n . I n t e r e s t i n g l y enough, pH was not found to be a f a c t o r i n CH^ %. Pearson c o r r e l a t i o n s done on the parameters l i s t e d above i n d i c a t e the s t r o n g e s t r e l a t i o n s h i p o c c u r r i n g between i o n i c s t r e n g t h and CH 4 %. R's f o r i o n i c s t r e n g t h vs. CH 4 % i n gas ranged from 0.35 to 0.70 f o r separate and combined w e l l a n a l y s i s . The r e s u l t i n g stepwise m u l t i p l e r e g r e s s i o n a n a l y s i s equations attempting to p r e d i c t CH 4 % are l i s t e d below f o r each. l a n d f i l l except S t r i d e Ave., where no c o r r e l a t i o n between any of the v a r i a b l e s and CH^ % was found. . MATSQUI LANDFILL CH % = 29.31 + 28.57 ( I o n i c Strength) - 1.22 (Gas Flow) + ... ... + 8.00 (C0 2 Flux) R 2 = 0.5725 S i g F < 0.000 N = 49 RICHMOND LANDFILL CH 4 % = 31.66 +0.725 (Tg) + 0.189 (C0 2 Flux) R 2 = 0.2319 S i g F < 0.000 N = 86 PREMIER ST. LANDFILL 130 CH % = -27.93 + 1.334 (Tg) - 9. 13. (Gas Flow) + 67.19.\"(CO- Flux) ... + 358.47 (Ionic Strength) R 2 = 0.8288 S i g F < 0.000 N =30 The r e s u l t s of these equations i n d i c a t e the best c o r r e l a t i o n of v a r i a b l e s to CH^ % are from Premier S t . data, which was expected s i n c e the v a r i a b i l i t y i n v a r i a b l e s : i s not as extreme as • • . 2 Richmond or Matsqui L a n d f i l l . Because of the low R 's and non-normal d i s t r i b u t i o n of i o n i c s t r e n g t h i n Matsqui, a l l three equations are c o n s i d e r e d suspect f o r p r e d i c t i n g CH^ % i n a given sample w e l l . T h i s was a l s o the case when McBean and Farquhar (1980) t r i e d r e g r e s s i n g 5 day cumulative p r e c i p . and ambient \" a i r 2 temp, on t h e i r methane percent data. T h e i r r e s u l t s i n d i c a t e R 's. of l e s s than 0.5. Regressions on separate sample w e l l s were not attempted because of time c o n s t r a i n t s and the sample p o p u l a t i o n (N = 15) was c o n s i d e r e d too small f o r m u l t i p l e r e g r e s s i o n . Each parameter that appeared i n the three equations i s b r i e f l y mentioned below e x p l a i n i n g why they may i n f l u e n c e CH 4 %: 1. Gas Temperature (Tg) - The i n c r e a s e in Tg was shown to a have a concomitant response with an i n c r e a s e i n CH^ %. Increase i n both parameters i s probably the r e s u l t of a combination of i n c r e a s e d m i c r o b i a l a c t i v i t y caused by an increase\" i n ambient a i r temperature (Ta). Decrease of Tg i s mainly due to a combination o f Ta and c o o l e r p r e c i p i t a t i o n t h at has i n f i l t r a t e d . 2. S t a t i c Gas Flow - An i n c r e a s e i n both gas flow and CH 4 % i s again probably a f u n c t i o n of i n c r e a s e d m i c r o b i a l a c t i v i t y . 131 However, there might a l s o be a s i t u a t i o n where i n c r e a s e d gas flow decreases CH 4 % because of mass d i l u t i o n . 3. CC>2 Flux - T h i s parameter i s a f u n c t i o n of s t a t i c gas flow and CC>2 %, which can e i t h e r cause an i n c r e a s e or decrease in C H4 • 4. Ionic Strength (I) - T h i s parameter i s c a l c u l a t e d from lea c h a t e s p e c i f i c c o n d u c t i v i t y as shown i n Appendix B.5. T h i s was the only l e a c h a t e - s p e c i f i c v a r i a b l e that stayed i n the r e g r e s s i o n equation. Since t h i s v a r i a b l e r e f l e c t s the c o n c e n t r a t i o n of d i s s o l v e d ions i n s o l u t i o n , an i n c r e a s e i n d i s s o l v e d ions had the e f f e c t of i n c r e a s i n g CH 4 %. T h i s i n c r e a s e i s most l i k e l y a r e s u l t of higher s t r e n g t h l e a c h a t e being f l u s h e d i n t o the methane producing region or l e s s d i l u t i o n of l e a c h a t e from decreased r a i n f a l l i n f i l t r a t i o n . In a d d i t i o n to the parameters mentioned above, l a n d f i l l age was c o n s i d e r e d to be a f a c t o r i n CH 4 %. Because of i t ' s advanced age, S t r i d e Ave. was o r i g i n a l l y c o n s i d e r e d to have a very low methane pet. which was not the case when an assessment of the r e s u l t s of four of the S t r i d e Ave. w e l l s was made (Appendix D) . Probably the main reason why S t r i d e Ave c o n s i s t e n t l y e x h i b i t e d some of the highest CH 4 percentages in the study may stem from the f a c t that during the study p e r i o d , the w e l l e x t r a c t i o n system was never o p e r a t i o n a l , so steady s t a t e CH 4 p r o d u c t i o n o c c u r r e d with no e x t e r n a l perturbances. However, t h i s i s not always the case when the e x t r a c t i o n system i s o p e r a t i n g . CH 4 percentage has been observed to drop r a p i d l y i n some we l l s (Len Hanson, pe r s . 1 32 comm., 1987) a f t e r pumping. T h i s decrease i n CH 4 % i s probably a r e s u l t of not only a i r i n t r u s i o n , but a l s o gas pr o d u c t i o n r a t e s that l a g f a r . b e h i n d the e x t r a c t i o n flow r a t e . So even though S t r i d e Ave may have r e l a t i v e l y high methane percentages, i t s mass prod u c t i o n r a t e s of methane are much lower than the younger Matsqui and R i c h m o n d . l a n d f i l l s which s t i l l produce high CH 4 % even duri n g continous pumping. In the l a n d f i l l s where gas e x t r a c t i o n was o p e r a t i o n a l , attempts to c o r r e l a t e CH 4 % v a r i a t i o n with o p e r a t i o n a l f l u c t u a t i o n s were s u c c e s s f u l i n only two sample w e l l s , P2 Premier and F5 Matsqui. Well P2 Premier was on constant vacuum throughout the study p e r i o d while F5 Matsqui had i n t e r m i t t e n t vacuum a p p l i e d to i t durin g winter demand p e r i o d s . R e s u l t s show the l a r g e drop i n CH 4 % i n P2 may be caused by a combination of p r e c i p i t a t i o n i n f i l t r a t i o n and decrease i n gas temperature. Recovery of the methane pet. may be hampered by the constant vacuum a p p l i e d t o the system, s i n c e the r a t e of a i r i n t r u s i o n probably exceeds a decreased r a t e of methane p r o d u c t i o n . T h i s high r a t e of a i r i n t r u s i o n probably causes a volume d i l u t i o n of methane. The i n t e r m i t t e n t drops of CH 4 % i n F5 Matsqui may be a f u n c t i o n of i n t e r m i t t e n t w e l l pumpage accompanying the e f f e c t s of p r e c i p i t a t i o n i n f i l t r a t i o n and gas temperature decrease. 5.4. VARIABLES THAT AFFECT AMMONIA GAS CONCENTRATION 5.4.1. INTRODUCTION NH,-N gas c o n c e n t r a t i o n ranged from non-detectable (< lOppb) 133 to over 600 ppb du r i n g the 8 month study. R e s u l t s i n NH^-N gas d i s t r i b u t i o n from the four l a n d f i l l s were s u r p r i s i n g s i n c e lower than expected c o n c e n t r a t i o n s o c c u r r e d i n Richmond while much higher than expected l e v e l s were det e c t e d i n S t r i d e Ave. T h i s was unusual s i n c e Richmond had q u i t e average to high NHg-N c o n c e n t r a t i o n s i n the le a c h a t e , while S t r i d e Ave. e x h i b i t e d very low NH^-N c o n c e n t r a t i o n s . The reasons f o r t h i s are not q u i t e apparent, but w i l l be t h e o r i z e d i n a l a t e r s e c t i o n . Throughout the study, most l a n d f i l l gas NHj-N l e v e l s moved in a general d e c r e a s i n g trend, dropping to t h e i r lowest l e v e l s i n the winter months. When t h i s study began, t h i s author f e l t there were maybe four parameters that a f f e c t e d the temporal v a r i a t i o n of NH^-N gas c o n c e n t r a t i o n s . These were pH and NH^-N in l e a c h a t e , methane f l u x and p r e c i p i t a t i o n i n f i l t r a t i o n . The pH of the s o l u t i o n was b e l i e v e d to c o n t r o l the f r a c t i o n of NH^ a v a i l a b l e f o r t r a n s f e r i n t o the gas phase. Higher NH^-N i n the le a c h a t e was b e l i e v e d to r e f l e c t a higher NH^-N i n the gas as r e g u l a t e d by Henry's Law. Methane f l u x was co n s i d e r e d important because of the p o s s i b i l i t y that methane flow c o u l d be a c t i n g as a s t r i p p i n g mechanism w i t h i n the l a n d f i l l causing a c c e l e r a t e d NH^-N t r a n s f e r i n t o the gas phase. Hence, higher methane f l u x e s were c o n s i d e r e d to r e s u l t i n higher NH^-N gas c o n c e n t r a t i o n s . L a s t l y , p r e c i p i t a t i o n i n f i l t r a t i o n was g e n e r a l l y c o n s i d e r e d to speed up m i c r o b i a l metabolic r a t e s r e l e a s i n g more NH^-N i n t o the gas phase. Post a n a l y s i s on these c o n t r o l parameters i n d i c a t e that none 1 34 of the o r i g i n a l assumptions were true on any c o n s i s t e n t b a s i s . Temporal v a r i a b i l i t y of these parameters vs. NH^-N f o r 9 of t h e ; study w e l l s are presented i n F i g s 5.20 through 5.63 and d i s c u s s e d in more d e t a i l l a t e r . In a d d i t i o n to these four parameters, gas temp, was p l o t t e d , s i n c e i t was found to be the parameter a f t e r post-sampling a n a l y s i s to e x p l a i n the v a r i a b i l i t y of NH^-N gas. The w e l l s p l o t t e d were B8, D9, C6, D.55 Richmond, F2, F5 Matsqui, F2, F7 S t r i d e Ave. and P2 Premier S t . . These w e l l s were chosen : for p l o t t i n g because a l l 9 w e l l s possesed complete s e t s (15) of l e a c h a t e and gas data. 5.4.2. PRECIPITATION D i r e c t i n s p e c t i o n of F i g ' s 5.20 through 5.27 show the temporal v a r i a t i o n of NH^-N gas and weekly p r e c i p i t a t i o n i n 8 of the w e l l s . Weekly p r e c i p i t a t i o n i s shown i n the bar c h a r t with the NH^-N gas shown on the connected l i n e p l o t . In n e a r l y a l l the wells,, there i s a l a r g e f l u c t u a t i o n of NH^-N gas c o n c e n t r a t i o n , v a r i a t i o n which i n most i n s t a n c e s i s around 100 % of the standard d e v i a t i o n (see Appendix D). G e n e r a l l y , i n most i n s t a n c e s , the trend i s NH^-N c o n c e n t r a t i o n s to drop o f f r a p i d l y d u r i n g the f i r s t high p r e c i p i t a t i o n . p e r i o d i n November. Pearson c o r r e l a t i o n a n a l y s i s i n d i c a t e some s l i g h t negative c o r r e l a t i o n between p r e c i p i t a t i o n and Nfr^-N gas i n combined w e l l a n a l y s i s of a l l four l a n d f i l l s . The r v a l u e s range from -0.3745 to -0.5391. For t h i s and any other s t a t i s t i c a l a n a l y s i s , the p r e c i p i t a t i o n v a r i a b l e was taken as the cumulative 2 week p r e c i p i t a t i o n preceeding the g i v e n sample p e r i o d . T h i s was PRECIPITATION in mm PRECIPITATION in mm M Ln Ul O N H 3 - N IN LANDFILL GAS ppb M o N H 3 - N IN LANDFILL GAS ppb ge i PRECIPITATION in mm '0, ° cn O NH3-N IN LANDFILL GAS ppb PRECIPITATION in mm J0^ TIM rn 5' UJ ont hs NH3-N IN LANDFILL GAS ppb LZ I GAS TEMP. IN Celsius pH 3 3 o IT N H 3 - N IN LANDFILL GAS ppb N H 3 - N IN LANDFILL GAS ppb 2Z I GAS TEMP. IN celsius pH NH3-N IN LANDFILL GAS ppb u ' NH3-N IN LANDFILL GAS ppb 6£ l 19 I N H 3 - N IN L E A C H A T E m g / L GAS TEMP. IN celsius pH N H 3 - N IN LANDFILL GAS ppb °° N H 3 - N IN LANDFILL GAS ppb 2 M NH3 -N IN LANDFILL GAS ppb w NH3-N IN LANDFILL GAS ppb 146 assumed to be a r e l i a b l e estimate of the e f f e c t i v e p r e c i p i t a t i o n i n f l o w i n t o the system between sample p e r i o d s . T h i s s c e n a r i o was decided upon because c a l c u l a t i n g an e f f e c t i v e p r e c i p i t a t i o n i n f l u x through a water balance was cumbersome and a l s o r e q u i r e d more s i t e - s p e c i f i c v a r i a b l e s than had been c o l l e c t e d f o r t h i s study. Probably the most accurate way to do a s t a t i s t i c a l a n a l y s i s on t h i s time-dependent p r e c i p i t a t i o n v a r i a b l e and NP^-N would be through a Box-Jenkins time s e r i e s a n a l y s i s , which was not attempted because of time c o n s t r a i n t s . There a number of reasons why p r e c i p i t a t i o n i n f l u x may be d e c r e a s i n g NH^-N gas c o n c e n t r a t i o n s . They are l i s t e d i n p o i n t form below: 1. The e f f e c t i v e d i l u t i o n of the l e a c h a t e and unsaturated zone may decrease the amount of ammonia mass a v a i l a b l e f o r mass t r a n s f e r i n t o the gas phase. 2. The \"wetting f r o n t \" of the lower pH i n f i l t r a t i n g r a i n f a l l a c t s as an e f f e c t i v e sink f o r NH^-N gas b y . r e s o l u b i l i z i n g the NH3-N and p r o t o n a t i n g t h i s to NH^ + hence, removing i t from the gas phase. 3. P r e c i p i t a t i o n c o u l d be \"choking\" or shock l o a d i n g the m i c r o b i a l fauna that produce NH^-N as a waste product, r e s u l t i n g in l e s s NH^-N a v a i l a b l e to t r a n s f e r . Out of these three reasons, probably the c o u p l i n g of #1 and #2 i s the dominant, mechanism in a f f e c t i n g NH^-N gas c o n c e n t r a t i o n s . 147 5.4.3. NH3-N IN LEACHATE In most cases, l e a c h a t e NH^-N c o n c e n t r a t i o n i s d e c r e a s i n g throughout the study p e r i o d much l i k e the.NH^-N gas does. There are exceptions such as C6 Richmond (Fig.5.36) which d i s p l a y s a semi-inverse r e l a t i o n s h i p and F5 Matsqui, whose le a c h a t e values may vary from 2000 mg/L down to 150 mg/L but the NH^-N i n the gas does not r e f l e c t t h i s change. The reason f o r t h i s v a r i a b i l i t y c o n c e n t r a t i o n s i n F5 Matsqui i s again r e l a t e d to a cracked c a s i n g where l a r g e volumes of rainwater d i l u t e the l e a c h a t e at c e r t a i n times f o l l o w e d by recovery to f u l l s t r e n g t h ( F i g . 5.48). Even though some of the p l o t s i n d i c a t e a p o s s i b l e i n t e r r e l a t i o n s h i p between NHg-N in l e a c h a t e and gas,, only Richmond L a n d f i l l i n d i c a t e s any s i g n i f i c a n t c o r r e l a t i o n between v a r i a b l e s . The r was found to be a f a i r l y low 0.4258. One S t r i d e Ave w e l l , F2 ( F i g . 5.52) shows a profound masking of the two parameters but only c o r r e l a t e s to an r of 0.5605 and i s not regarded as s i g n i f i c a n t s i n c e i t exceeds the p of 0.025. One reason why NH^-N i n leachate may not d e s c r i b e more of the v a r i a t i o n i n NH^-N gas, c o u l d stem from the f a c t that most of the mass t r a n s f e r of NH^-N i n t o the gas phase probably occurs i n the unsaturated zone (esp. i n the deeper w e l l s ) where e n t i r e l y d i f f e r e n t v a r i a t i o n s and c o n c e n t r a t i o n s of NH^-N and pH may occur. T h e r e f o r e , sampling the leachate may not e n t i r e l y d e s c r i b e the whole ammonia system, e s p e c i a l l y i n w e l l s (other than Richmond) where unsaturated zones g r e a t e r than 8 meters e x i s t . 1 48 5.4.4. LEACHATE pH In most i n s t a n c e s , the pH f o l l o w s the same p a t t e r n s as the NH^-N d u r i n g the study p e r i o d . T h i s i s probably due to p r e c i p i t a t i o n i n f i l t r a t i o n d e c r e a s i n g gas p r o d u c t i o n , which causes an accumulation i n organic a c i d s to suppress the pH. T h i s rainwater may a l s o help to d i l u t e the b u f f e r i n g a l k a l i n i t y to cause the system to be more s u s c e p t i b l e to pH drop from these organic a c i d s . The r e s u l t s o f . t h e Pearson c o r r e l a t i o n i n d i c a t e that there are no s i g n i f i c a n t s t a t i s t i c a l r e l a t i o n s h i p s between pH and NH^-N gas c o n c e n t r a t i o n s in any of the l a n d f i l l s . There may be a r e l a t i o n s h i p due to a combination of pH and le a c h a t e NH^-N c o n t r o l l i n g the formation of NH^-N gas as r e g u l a t e d by the ammonia e q u i l i b r i u m e x p r e s s i o n a l r e a d y d i s c u s s e d . 5.4.5. METHANE FLUX The e f f e c t of a i r s t r i p p i n g by methane f l u x caused by gas pr o d u c t i o n was n o t i c e d i n a few w e l l s such as B8, D9, C6 Rich and F7 S t r i d e ( F i g ' s 5.30, 5.34, 5.38 and 5.58 r e s p e c t i v e l y ) . These p l o t s i n d i c a t e some e l e v a t e d c o n c e n t r a t i o n s of NH3-N gas with i n c r e a s e d CH 4 f l u x . Even though these p l o t s i n d i c a t e some i n t e r r e l a t i o n s h i p , the Pearson c o r r e l a t i o n c o e f f i c i e n t s i n d i c a t e that none of the four w e l l s show a s i g n i f i c a n t c o r r e l a t i o n ( r ) . The only two w e l l s found to have s i g n i f i c a n t r's were two non-leachate wells., F1 and F4 Matsqui, which e x h i b i t r's of 0.6439 and 0.6144. P o t e n t i a l reasons why CH. f l u x does not e x p l a i n any 149 v a r i a b i l i t y i n NH^-N gas are l i s t e d i n p o i n t form below: 2 1. The in c r e a s e d f l u x i n kg CH^/cm -day may a c t u a l l y c r e a t e a l a r g e volume d i l u t i o n of gaseous components so values are i n . t u r n , lower than expected. T h i s c o u l d be the case at S t r i d e Ave where low methane f l u x e s are a s s o c i a t e d with higher than expected NH^-N gas c o n c e n t r a t i o n s . 2. The i n t e r n a l v e l o c i t i e s of the methane flow around the ref u s e g r a i n s i s not a s u b s t a n t i a l enough f o r c e to a c c e l e r a t e the normal mass t r a n s f e r r a t e s of ammonia i n t o the gas phase. 3. The v a r i a t i o n i n methane f l u x e s are due to a n a l y t i c a l v a r i a t i o n i n many w e l l s . 5.4.6. GAS TEMPERATURE When t h i s study o r i g i n a l l y began, gas temperature (Tg) was not c o n s i d e r e d a v a r i a b l e that c o u l d a f f e c t c o n c e n t r a t i o n s of NH^-N i n gas. However, a f t e r the s t a t i s t i c a l and g r a p h i c a l a n a l y s i s , i t has become the parameter that best d e s c r i b e s the v a r i a t i o n of NH^-N i n gas. A l l of the p l o t s e x h i b i t a f a i r l y c o n s i s t e n t i n t e r r e l a t i o n s h i p between f a l l i n g gas temperature and d e c r e a s i n g NH^-N gas c o n c e n t r a t i o n . The s t a t i s t i c a l a n a l y s i s a l s o i n d i c a t e s a strong c o r r e l a t i o n between the two v a r i a b l e s . In the l i n e a r 2 r e g r e s s i o n a n a l y s i s , R 's generated from the l e a s t squares method were always gre a t e r f o r Tg than the other parameters analyzed (pH, NH^-N le a c h a t e , i o n i c s t r e n g t h , CH 4 and CG>2 f l u x ) . 2 The average R from each l a n d f i l l ranged from a low of 0.2504 at Premier S t . to a high of 0.5247 at Matsqui l a n d f i l l . R e s u l t s 150 from the Pearson c o r r e l a t i o n i n d i c a t e that 8 out of 18 w e l l s analyzed e x h i b i t a s i g n i f i c a n t c o r r e l a t i o n between v a r i a b l e s . A l l four combined w e l l a n a l y s i s a l s o e x h i b i t s i g n i f i c a n t c o r r e l a t i o n s ranging from a low of 0.4716 i n Richmond to a high of 0.6668 i n S t r i d e Ave.. Stepwise m u l t i p l e r e g r e s s i o n a l s o i n d i c a t e s Tg i s somewhat i n t e r r e l a t e d to NH^-N gas as i t was the only independent v a r i a b l e that f i t i n t o the equation p r e d i c t i n g NH^-N gas. The one exception t o t h i s rule.was Premier S t . where leachate temp (Tw) r e p l a c e d Tg as the lone independent v a r i a b l e . The r e s u l t s of these stepwise r e g r e s s i o n s are l i s t e d below: MATSQUI LANDFILL NH3-N GAS (ppb) = -267.61 + 33.2 (Tg) R 2 = 0.4551 S i g F<0.000 N = 4 9 STRIDE AVE. LANDFILL NH3-N GAS (ppb) = -70.06 + 22.15 (Tg) R 2 = 0.3366 S i g F<0.000 N = 44 RICHMOND LANDFILL NH3-N GAS (ppb) = -68.42 + 10.84 (Tg) R 2 = 0.2224 S i g F<0.000 N = 86 PREMIER ST LANDFILL NH3-N GAS (ppb) = -908.77 + 48.10 (Tw) R 2 = 0.3171 S i g F=0.001 N =30 Ins p e c t i o n of the above, r e s u l t s i n d i c a t e some very low R 's which makes i t very d i f f i c u l t to have any confi d e n c e i n p r e d i c t i n g NH.-N gas c o n c e n t r a t i o n s from these equations. In 151 a d d i t i o n to f i n d i n g minimal s t a t i s t i c a l r e l a t i o n s h i p between v a r i a b l e s , a non-normal d i s t r i b u t i o n was d i s c o v e r e d i n both Matsqui and Richmond NH^-N data. Since these m u l t i p l e r e g r e s s i o n equations were reduced to a b i v a r i a t e r e g r e s s i o n equation, the r e s u l t s f o r each w e l l can be expressed g r a p h i c a l l y . These p l o t s are l o c a t e d i n F i g u r e s 5.64 through 5.67. These p l o t s e x h i b i t a l a r g e p o i n t s c a t t e r around the best f i t l i n e . T h i s p o i n t s c a t t e r . . . 2 . i s i n d i c a t i v e of very low R 's l i k e the ones c a l c u l a t e d i n t h i s a n a l y s i s . The somewhat l i n e a r r e l a t i o n s h i p between Tg and NH^-N gas c o u l d be due to three reasons which are l i s t e d below: 1. The higher l a n d f i l l gas temperature c o u l d i n c r e a s e m i c r o b i a l metabolism r a t e s , or v i c e - v e r s a . T h i s may cause a r e l e a s e of more NH^-N f o r mass t r a n s f e r i n t o the gas phase. 2. The greater the l a n d f i l l gas or l e a c h a t e temperature, the g r e a t e r the Henry's Law constant i s because of a decrease in s o l u b i l i t y . T h i s e f f e c t causes a g r e a t e r mass of NH^-N to be t r a n s f e r e d i n t o the gas phase e l e v a t i n g NH^-N gas c o n c e n t r a t i o n s . 3. The lower l a n d f i l l temperatures are a r e s u l t a n t of p r e c i p i t a t i o n i n f i l t r a t i o n which, alr e a d y d i s c u s s e d c o u l d be a sink f o r NH^-N gas. So i n t h i s s c e n a r i o , Tg or Tw are i n d i r e c t causes f o r NH^-N gas v a r i a t i o n . The most important f a c t o r causing NH^-N gas v a r i a t i o n by Tg or Tw i s probably mechanism #2, where mass t r a n s f e r i s enhanced by higher temperatures. For #1 to be v a l i d , there would tend to be a g e n e r a l i n c r e a s e i n NH,-N i n the l e a c h a t e , which was not 152 FIG. 5.64 -REGRESSION PLOT OF GAS TEMP VS. NH3-N IN GAS MATSQUI LANDFILL 1500 C L C L CO < I 1000-500 NH3-N GAS - -267.61 + 33.2 (Tg) R 2 - 0.4551 x ) & m m * x 0 5 10 15 20 25 GAS TEMP in celsius 30 FIG. 5.65 -REGRESSION PLOT OF GAS TEMP vs. NH3-N IN GAS STRIDE AVE LANDFILL 1000 C L a- 750-j CO < I NH3-N GAS - -70.06 + 22.15 (Tg) R 2 - 0.3366 X X x x X X X X X * x ^ x j ^ x x X T 5 10 15 20 25 GAS TEMP in celsius 30 FIG . 1 53 5.66 REGRESSION PLOT OF GAS TEMP vs. NH3-N IN GAS RICHMOND LANDFILL 800 Q_ Q. 600-CO < O z 400-z 1 1 hO 200-~T X NH3-N GAS - - 6 8 . 4 2 + 1 0 . 8 4 (Tg) X £ X x x )0|0Q( )0|( n )0|000( | 5 10 15 20 25 30 35 GAS TEMP in Celsius REGRESSION PLOT OF LEACHATE TEMP vs. NH3-N IN GAS PREMIER ST. LAND 500 g; 400 -| CO ^ 300H z 200-1 I X 100-0 NH3-N GAS - - 9 0 8 . 7 7 + 4 8 . 1 0 (Tw) R2 - 0 .3171 ^ x x x x — T 1 ¥ 18 20 22 24 26 LEACHATE TEMP in celsius 1 54 found. However, t h i s c o u l d happen i n the unsaturated zone which would not be n o t i c e d i n my r e s u l t s . The i n d i r e c t r e l a t i o n s h i p of #3 may be important, but because p r e c i p i t a t i o n was r e j e c t e d from the r e g r e s s i o n equation, the impact of p r e c i p i t a t i o n on NH^-N gas i s u n c e r t a i n . 5.4.7. OTHER PARAMETERS Two other parameters monitored to see i f they c o n t r i b u t e d to the temporal v a r i a b i l i t y of NH^-N gas were, s t a t i c gas flow and i o n i c s t r e n g t h of the l e a c h a t e . An i n c r e a s e i n gas flow was o r i g i n a l l y b e l i e v e d much l i k e CH^ f l u x , to cause an in c r e a s e i n NH^-N i n the gas phase from a c c e l e r a t e d mass t r a n s f e r or consequently, cause a decrease due to mass d i l u t i o n . R e s u l t s however, i n d i c a t e s t a t i c flow showed minimal c o r r e l a t i o n with NH^-N gas. An i n c r e a s e i n the i o n i c s t r e n g t h of leac h a t e was g e n e r a l l y b e l i e v e d to decrease the s o l u b i l i t y of NH^-N i n the l e a c h a t e thereby causing an inc r e a s e of NH^-N i n t o the gas phase. In a n a l y s i s of the data, only one w e l l (F2 Matsqui) e x h i b i t e d any i n t e r r e l a t i o n s h i p between the v a r i a b l e p a i r with a s i g n i f i c a n t r of 0.6026. D e f i c i e n c y i n c o r r e l a t i o n with i o n i c s t r e n g t h and NHg-N gas may be a r e s u l t of e s t i m a t i n g i o n i c s t r e n g t h from c o n d u c t i v i t y measurements (Appendix B.5) i n s t e a d of c a l c u l a t i n g i o n i c s t r e n g t h from a complete lea c h a t e i o n i c a n a l y s i s . 5.5. LANDFILL GAS ORGANIC CONTAMINANTS Q u a l i t a t i v e data c o l l e c t e d from Tenax GC t r a p a n a l y s i s on gases from three of the four l a n d f i l l s i s l i s t e d i n t a b l e s 5.8 155 through 5.11. The t a b l e s are ordered i n a s p e c i f i c sequence determined by the type of compound. The d i v i s i o n s of the t a b l e are d e s c r i b e d below: 1. CH 4, C0 2, N 2, 0 2 percentages 2. Halogenated Hydrocarbons 3. Benzene and Toluene Compounds 4. A l c o h o l s 5. Saturated and unsaturated hydrocarbons 6. M i s c e l l a n e o u s compounds No organic a n a l y s i s was done on S t r i d e Ave. gas because of time c o n s t r a i n t s and the g e n e r a l assumption that not many or g a n i c s would be de t e c t e d i n t h i s o l d e r l a n d f i l l . Compounds that were not de t e c t e d but g e n e r a l l y c o n s i d e r e d to be i n s u f f i c i e n t c o n c e n t r a t i o n (sub ppm) were v i n y l c h l o r i d e and t h i o l group compounds. V i n y l c h l o r i d e i s c a r c i n o g e n i c while t h i o l group compounds c o n s t i t u t e a major f r a c t i o n of l a n d f i l l gas odor (Young and Parker, 1984).. V i n y l c h l o r i d e was expected to be found s i n c e i t i s a waste product of the PVC i n d u s t r y and a l s o a daughter product of the m i c r o b i a l l y mediated anaerobic degradation of c e r t a i n halogenated hydrocarbons ( i e , t e t r a c h l o r o e t h y l e n e ) common to these l a n d f i l l s (Refer to Vogel, C r i d d l e and McCarty, 1987). V i n y l c h l o r i d e has been found to be q u i t e abundant i n l a n d f i l l gas at c o n c e n t r a t i o n s up to 12,800 ppm i n a study by Stephens et a l . (1986). T h i o l group compounds were important to detec t not only f o r t h e i r odor p r o p e r t i e s but a l s o as a p o t e n t i a l i n t e r f e r e n c e source i n the NH,-N gas a n a l y t i c a l 156 WELL PI PREMIER ST January 20, 1988 Methane Carbon D i o x i d e N i t r o g e n Oxygen Tr 9.9% 70.7% 19.4% T e t r a c h l o r o e t h y l e n e Benzene and isomers (3) E t h y l Benzene Toluene Hexane and isomer Cyclohexane isomers (4) Heptane isomer Cycloheptane B i c y c l o h e p t a n e isomer 3-methyl pentane Methyl-cyclopentane isomers (2) C10-C12 hydrocarbons Pentene isomer Xylenes * Furan isomer Cyclohexanone isomer Benzaldehyde * Appearance of t h i s c o u l d be due to t r a p b l e e d TABLE 5.8 - L a n d f i l l gas VOC's dete c t e d by GC-MS and Tenax Trap 157 WELL F5 MATSQUI LANDFILL, A p r i l 13, 1988 Methane Carbon Dioxide Nitrogen Oxygen 1 ,2-dichloroethene T e t r a c h l o r o e t h y l e n e D i f l u o r o d i m e t h y l S i l a n e Benzene and isomers(8) Toluene Phenol Nonane Cyclohexane isomers (2) Xylene and isomer * Benzaldehyde and isomer 1-phenyl Ethanone * Appearance of t h i s could be due to t r a p b l e e d TABLE 5.9 - L a n d f i l l Gas VOC's d e t e c t e d by GC-MS and Tenax Trap 158 WELL F3 MATSQUI LANDFILL, A p r i l 22, 1988 Methane Carbon Dioxide Nitrogen Oxygen 50. 1 % 32.5 % 17.4 % Tr 1,2-dichloroethane T r i c h l o r o f l u o r o m e t h a n e 1.1- d i c h l o r o e t h e n e 1.2- d i c h l o r o e t h e n e T r i c h l o r o e t h y l e n e T e t r a c h l o r e t h y l e n e Dichlorobenzene T r i c h l o r o b e n z e n e Benzene and isomers (10) Tr i m e t h y l Benzene Tetramethyl Benzene isomers (3) Toluene Phenol Phenol isomers Dimethyl Cyclooctanemethanol isomer Hexane Heptane Cyclohexane isomers (3) Tetradecane Octane isomer Nonane and isomers (2) Decane and isomer Bicyclo-heptane isomers (2) Cycloundecane isomer Dodecane 1,3,5-cycloheptatriene 4-ethyl-2-octene Xylenes * Indene isomers (4) 1,1 D i e t h y l Ether 1,1'-Biphenyl Naphthalene and isomers (5) Phenyl-Oxazole isomer Benzofuran isomer * Appearance of t h i s could be due to t r a p b l e e d TABLE 5.10 - L a n d f i l l gas VOC's de t e c t e d by GC-MS and Tenax Trap 159 WELL C6 RICHMOND LANDFILL, A p r i l 22 and A p r i l 13, 1988 Methane 56.5 % Carbon Dioxide 43.5 % Nitrogen 0.0 % Oxygen 0.0 % Tr i c h l o r o f l u o r o m e t h a n e Methylene c h l o r i d e 1,2-dichloroethene T r i c h l o r o e t h y l e n e T e t r a c h l o r o e t h y l e n e 1,2-dichlorobenzene T r i c h l o r o b e n z e n e Fluorene Methane 54.3 % Carbon Dioxide 41.8 % Nitrogen 3.1 % Oxygen 0.7 % T r i c h l o r o f l u o r o m e t h a n e dichloromethane 1,2-dichloroethene T r i c h l o r o e t h y l e n e T e t r a c h l o r o e t h y l e n e Benzene and isomers (5) Tr i m e t h y l benzene isomer Tetramethyl benzene isomers (3) p r o p y l benzene^ Toluene p - i s o b u t y l Toluene Phenol isomers (2) B i c y c l o - o c t a n o l isomer Hexane Heptane and isomer Nonane and isomer T r i c y c l o h e p t a n e isomer Decane and Tridecane isomers Xylenes * Bicyclohexene isomer 3,9-Dodecadiene Indene isomers (3) T r i m e t h y l dihydro Indene Benzene and isomers (6) E t h y l Benzene Phenol Benzenemethanol-ethenyl Cyclobutane isomers P e n t y l Cyclopropane Cyclopentane isomer Xylenes * Methyl Indene and isomer E t h y l and Methyl E s t e r Butanoic A c i d Naphthalene and isomers (6) D i s u l f i d e isomers (2) Benzaldehyde Trans-Cyclohexanone isomer 1-phenyl-Ethanone Benzofuran isomer 2,2'-bifuran 1,1'-Biphenyl Methyl Benzofuran Dibenzofuran Acenaphthylene isomer * Appearance of t h i s c o u l d be due to t r a p b l e e d TABLE 5.11 - L a n d f i l l Gas VOC's d e t e c t e d by GC-MS and Tenax Trap 160 technique a l r e a d y d i s c u s s e d . The reason(s) v i n y l c h l o r i d e was not de t e c t e d i s probably due to a n a l y t i c a l l i m i t a t i o n s d u r i n g thermal d e s o r p t i o n of the trapped o r g a n i c s . On the other hand, t h i o l group compounds are more p o l a r and l e s s l i k e l y to be trapped on Tenax GC m a t e r i a l . Other t r a p p i n g m a t e r i a l such as Porapak Q as suggested by Brookes and Young (1983), or a n a l y s i s of the condensate may be more e f f e c t i v e i n d e t e c t i n g t h i o l s . I n s p e c t i o n of Tables 5.8 through 5.11 i n d i c a t e that up to 8 c h l o r i n a t e d hydrocarbons were det e c t e d . Probably the most abundant c l a s s of o r g a n i c s found were the s u b s t i t u t e d benzenes and r e l a t e d isomers. A l s o n o t i c a b l e i n Table 5.11 i s the gr e a t e r d e t e c t i o n of compounds i n C6 Richmond a f t e r the sampling technique was r e f i n e d . 5.6. PREDICTION OF NH3-N GAS THROUGH HENRY'S LAW 5.6.1. INTRODUCTION The law that governs the p a r t i t i o n i n g of a v o l a t i l e compound between the gas and aqueous phases i s commonly r e f e r r e d to as Henry's Law. The constant to Henry's Law (Hx) comes i n many u n i t s , but i s u s u a l l y r e p o r t e d as the p a r t i a l pressure (Pa) of the v o l a t i l e compound.divided by i t ' s mole f r a c t i o n (Xa) i n the aqueous phase as shown i n equation ( i ) : Hx = Pa/Xa V ( i ) Henry's Law constants are measured i n the l a b by three . common techniques l i s t e d below (From MacKay and Shiu, 1981): 1. The.use of vapor pressure and s o l u b i l i t y data. 161 2. D i r e c t measurement of a i r and aqueous c o n c e n t r a t i o n s . 3. Measurements of r e l a t i v e changes i n c o n c e n t r a t i o n w i t h i n one phase, while a f f e c t i n g a n e a r - e q u i l i b r i u m exchange with the other phase. A novel f o u r t h approach, c a l l e d \" E q u i l i b r i u m P a r t i t i o n i n g i n Closed Systems\" (EPICS), has been s i t e d by many to be a more accurate technique f o r measuring Hx's, e s p e c i a l l y f o r v o l a t i l e o r g a n i c s . T h i s technique i s d i s c u s s e d i n more d e t a i l by Gossett (1987). The main assumption f o r Henry's Law to be v a l i d i s that the aqueous and gaseous phases must be i n e q u i l i b r i u m . The gas.phase should behave i d e a l l y while the aqueous phase can behave non-i d e a l l y as long as the s o l u t i o n ( i e . , leachate) i s d i l u t e (< 0.05 mole f r a c t i o n ) . In t h i s data, a l l mole f r a c t i o n s are l e s s than 10 *V so Henry's law i s v a l i d . In the f o l l o w i n g s e c t i o n , four e n t i r e l y d i f f e r e n t Hx's w i l l be e v a l u a t e d f o r t h e i r p o t e n t i a l to p r e d i c t NH^-N i n the gas phase given the NH^-N c o n c e n t r a t i o n i n the l e a c h a t e . A f t e r e v a l u a t i n g the spreadsheet r e s u l t s , a s e c t i o n in. t h i s t h e s i s w i l l be devoted to d i s c u s s i n g the p o t e n t i a l reasons f o r d e v i a t i o n observed between the r a t i o of p r e d i c t e d versus measured NH3-N gas c o n c e n t r a t i o n s . 5.6.2. COMPARISON OF DIFFERENT HENRY'S LAW CONSTANTS 5.6.2.1. CORRECTED VAPOR PRESSURE METHOD Th i s method i s employed by MacKay and Shiu (1981) and others f o r c a l c u l a t i n g Henry's Constants from a v a i l a b l e s o l u b i l i t y and 162 vapor pressure data. Equation ( i i ) i s presented below: H 1 = Pc/S ( i i ) Where Pc = c o r r e c t e d vapor pressure (atm) S = S o l u b i l i t y of Ammonia in d i s t i l l e d water (moles/L) The c o r r e c t e d vapor pressure i s c o n s i d e r e d more accurate than the r e f e r e n c e vapOr pressure because the system i s non-i d e a l and d i l u t e . C o r r e c t e d vapor pressure i s a f u n c t i o n of the temperature and s o l u b i l i t y and i s c a l c u l a t e d i n Appendix B.10. Regression equations are used to c a l c u l a t e both the s o l u b i l i t y : and r e f e r e n c e vapor pressure as a f u n c t i o n of temperature. These equations are a l s o l i s t e d i n Appendix B.10. P o s s i b l e e r r o r s i n t r o d u c e d i n t o c a l c u l a t i n g t h i s constant, i n c l u d e the f o l l o w i n g : 1. V a r i a t i o n i n the r e f e r e n c e vapor pressure c a l c u l a t i o n . U n f o r t u n a t e l y , no c o e f f i c i e n t Of v a r i a t i o n was documented. 2. The small v a r i a t i o n i n the r e g r e s s i o n equation to estimate s o l u b i l i t y . The c o e f f i c i e n t of v a r i a t i o n (% C.V.) i s 2 l e s s than 1.0 % with the r being a r e s p e c t i b l e 0.999806. 3. S o l u b i l i t y data i s taken from pure water measurements, so e r r o r s are u n c e r t a i n when c o n s i d e r i n g a l e a c h a t e . S o l u b i l i t y of NH^ has been shown to decrease with i n c r e a s i n g i o n i c s t r e n g t h , so t h i s method may o v e r p r e d i c t s o l u b i l i t y i n non-pure systems. I n s p e c t i o n of the r e s u l t s i n Tables 5.12 through 5.19, i n d i c a t e that p t . #4 i s most l i k e l y the major cause behind the higher than usual r a t i o s between p r e d i c t e d and measured NH^-N i n gas. The o v e r p r e d i c t i o n of NH_-N i n gas i s most l i k e l y due to an 163 DATE NH3-N HI UH3 BY HI RATIO H2 KH3 BY H2 RATIO H3 NH3 by H3 RATIO H4 by NH3 by H4 RATIO S A S d o l t s / (ppb) H l / H E A S ( a t i / I ) (ppb) H2/HEAS ( M U S / (ppb) H3/KEA5 F O R H U U (ppb) H 4 / H E A S (ppb) ( L - i t t ) (L -a t i ) AS f(T) F l MATSQUI 01/12/88 44.8 27.1 1823.3 40.6832 0.57 507.5 11.3232 143.7 344.4 7.6840 3.84E+03 158.7 3.5422 01/26/88 39.4 19.3 2561.8 63.0311 0.69 843.2 21.4049 116.6 424.7 10.7803 3.23E+03 188.7 4.7913 02/09/88 30.2 20.8 1842.9 60.9780 0.67 644.6 21.3278 119.6 320.6 10.6080 3.30E*03 150.9 4.9931 03/01/88 140.4 15.3 23(6.8 16.8561 0.78 676.0 4.8145 100.0 36S.9 2.6059 2.83E»«3 177.6 1.2650 03/29/88 37.1 20.6 1186.1 31.9394 0.69 399.6 10.7587 116.6 210.1 5.6578 3.23Ei03 102.8 2.7678 F2 HATS8UI 08/0S/87 204.7 9.0 08/25/87 408.4 9.3 09/08/87 397.4 8.3 09/22/87 311.4 9.3 10/06/87 166.5 9.6 10/20/87 143.1 11.6 11/10/87 135.7 11.9 11/24/87 40.0 12.7 : 12/08/87 25.8 19.3 12/29/87 18.2 17.0 01/12/88 23.7 23.7 01/26/88 38.7 15.5 02/09/88 33.2 16.0 03/01/88 69.3 15.0 03/29/88 72.1 15.5 12/08/87 19.8 21.0 12/29/87 35.9 21.0 01/12/88 26.7 21.0 01/26/88 29.6 15.0 02/09/88 52.0 17.1 03/01/88 135.9 12.3 03/29/88 44.7 16.1 9218.9 7053.3 10815.4 9773.9 11834.8 10136.7 12268.7 33393.5 220.0 2453.9 477.8 117.9 46.8 2509.9 1314.1 45.0424 17.2725 27.2178 31.3837 71.0840 70.8429 90.4243 834.3575 8.5443 134.8581 20.1736 3.0430 1.4124 36.2206 18.2185 0.87 0.87 0.90 0.87 0.90 0.87 0.84 0.84 0.69 0.69 0.60 0.75 0.79 0.75 0.75 1465.9 1144.3 1602.6 1560.6 2049.0 2025.2 2429.3 6907.2 56.9 562.0 128.5 25.2 10.9 555.9 284.3 7.1620 2.8021 4.0330 5.0110 12.3069 14.1539 17.9050 172.5808 2.2108 30.8862 5.4267 0.6509 0.3298 8.0223 3.9417 F3 HATSQUI 86.0 86.0 81.9 86.0 81.9 86.0 90.4 90.4 116.6 116.6 136.3 105.2 97.5 105.2 105.2 968.4 763.4 1092.5 1057.9 1390.5 1363.4 1616.8 4691.7 36.5 357.5 83.0 17.4 7.7 359.0 194.1 4.7312 1.8695 2.7494 3.3968 8.3S21 9.5282 11.9166 117.2254 1.4164 19.6465 3.5052 0.4495 0.2313 5.1810 2.6911 2.52C+40 2.52E+03 2.42E*03 2.52E««3 2.42£*03 2.52E*03 2.63E+03 2 . 6 3 M 3 3.23£*03 3.23E+03 3.&8EHK3 2.97E+03 2.80EHI3 2.97E+03 2.97E«03 416.1 2.0332 322.0 0.7885 458.9 1.1547 448.8 1.4410 584.2 3.5090 575.3 4.0208 688.0 5.0707 1958.7 48.9402 16.5 0.6395 160.5 8.8190 38.8 1.6370 7.8 0.2002 3.3 0.1008 164.6 2.3758 92.7 1.2854 1600.1 939.2 S45.8 S31.0 158.8 92.4 151.3 81.0053 26.1848 20.4326 17.9519 3.0532 0.6801 3.3834 0.66 443.0 22.4275 122.8 273.8 13.8607 3.3TE+03 129.7 6.5668 0.66 258.0 7.1935 122.8 160.7 4.4805 3 . 3 7 M 3 77.2 2.1533 0.66 145.0 5.4266 122.8 93.4 3.4962 3.37E+03 43.6 1.6332 0.78 116.9 3.9515 100.0 79.4 2.6859 2.85E*03 36.9 1.2469 0.78 40.0 0.7685 100.0 27.1 0.5216 2.82*03 12.1 0.2333 0.87 18.5 0.1358 86.0 13.3 0.0976 2.52£*03 6.4 0.0472 0.75 33.7 0.7S40 105.2 23.1 0.5163 2 . 9 7 M 3 11.4 0.2547 TABLE 5.12 - R e s u l t s o f H e n r y ' s Law C o m p a r i s o n F l , F2, F3 M a t s q u i - H e n r y ' s Law C o n s t a n t H2 - H e n r y ' s Law C o n s t a n t H3 = H e n r y ' s Law C o n s t a n t H4 - H e n r y ' s Law C o n s t a n t C o r r e c t e d V a p o r P r e s s u r e Meth< Mole F r a c t i o n Method G i b b s F r e e E n e r g y Method S o l u b i l i t y - E q u i l i b r i u m Method 164 DATE NH3-N HI XH3 8Y HI RATIO H2 NH3 BY H2 RATIO H3 NH3 by H3 RATIO H4 by NH3 by H4 RATIO SAS d o l e s / (ppb) Hl/HEAS ( i t i / I ) (ppb) H2/NEAS ( u l « / (ppb) H3/KA5 rORHULA (ppb) .H4/XEAS (ppb) ( L - i t i ) =========: ========= ;=—~~=~ ( L - i t i ) . - - . = - 5 = = - . AS f(T) . . . . . . . . . . . ======== F5 HATSOUI 08/05/87 22.0 9.9 4575.0 207.7523 0.87 901.5 40.9395 86.0 526.2 23.8932 2.52E+03 227.0 10.3100 08/23/87 601.6 9.1 19743.9 32.8197 0.90 3980.2 6.6162 81.9 2182.0 3.6271 2.42E+03 938.8 1.5603 09/08/87 75.9 9.9 19145.1 252.2225 0.87 3986.3 52.5164 86.0 2201.8 29.0076 2.52E+03 956.8 12.6057 09/22/83 143.9 8.5 14740.2 102.4617 0.87 2624.8 18.2455 86.0 1459.4 10.1446 2.52E+03 634.5 4.4107 10/06/87 99.1 8.8 23934.9 241.4131 0.90 4597.0 46.3668 81.9 2S66.4 25.8856 2.42E+03 1109.8 11.1942 10/20/87 276.9 9.9 16482.6 59.S349 0.87 3442.5 12.4342 86.0 1895.6 6.8470 2.52£t03 867.1 3.1320 11/10/87 167.6 13.5 2553.1 15.2349 0.81 591.0 3.5263 95.1 363.7 2.1704 2.74E+03 162.8 0.9717 11/24/87 37.3 16.0 33.1 0.8876 0.78 8.1 0.2183 100.0 5.3 0.1418 2.8SE+03 2.4 0.0647 12/08/87 13.7 16.5 62.7 4.S932 0.78 16.1 1.1779 100.0 10.4 0.7588 2.85E+03 4.7 0.3437 12/29/87 72.9 17.7 4335.8 39.4643 0.78 1404.1 19.2569 100.0 766.3 10.3098 2.8SE*03 352.8 4.8391 01/12/88 30.8 16.0 9305.9 302.42B3 0.76 2769.4 90.0030 102.6 1452.2 47.1960 2.91E+03 675.5 21.9541 01/26/88 36.0 17.1 348.0 9.6723 0.79 96.8 2.6918 97.5 61.0 1.6948 2.80EMJ3 28.2 0.7840 02/09/88 — 20.4 250.9 — 0.72 72.6 — 110.7 46.3 - - 3.10E+03 — — 03/01/88 69.1 14.5 2680.3 38.7702 0.81 697.3 10.0869 95.1 407.6 5.8952 2.74E+03 169.2 2.4472 03/29/88 — 16.5 845.4 — 0.78 230.9 — 100.0 139.7 - 2.85E+03 — — - r a Miseui 11/10/87 102.9 12.0 0.4 0.0036 0.87 0.1 0.0007 86.0 0.1 0.0005 2.52E+03 0.0 0.0002 11/24/87 40.0 14.5 0.1 0.0014 0.81 0.0 0.0003 95.1 0.0 0.0002 2.74E+03 0.0 0.0001 12/08/87 19.9 17.8 0.0 0.0020 0.73 0.0 0.0004 107.9 0.0 0.0003 3.04E+03 0.0 0.0002 12/29/87 32.4 19.7 1.0 0.0294 0.73 0.2 0.0075 107.9 0.2 0.0054 3.04E+03 0.1 0.0025 01/12/88 28.3 27.2 0.2 0.0067 0.63 0.1 0.0020 129.3 0.0 0.0014 3.52£»03 0.0 0.0007 01/26/88 59.8 22.4 0.4 0.0071 0.66 0.1 0.0018 122.8 0.1 0.0013 3.37E+03 0.0 0.0006 02/09/88 27.3 32.1 0.3 0.0092 0.57 0.1 0.0031 143.7 0.1 0.0021 3.84E*03 0.0 0.0010 03/01/88 82.4 20.0 — 0.0000 0.69 — — 116.6 — - 3.23E+03 — — 03/29/88 70.3 25.4 ~ 0.0000 0.63 — — 129.3 — - - 3.52E»03 — — TABLE 5.13 R e s u l t s o f Henry's F5, F8 M a t s q u i Law C o m p a r i s o n 165 ========== :======== ========= =========: :========; ========= ========== :======== ========= :=========: :========= ========= DATE KH3-H ~\" HI XH3 BY HI RATIO H2 XH3 BY H2 RATIO H3 NH3 by H3 RATIO H4 by KH3 by H4 RATIO 6AS ( M l t f / (ppb) Hl/HEAS U t i / I ) (ppb) H2/KEAS ( M l K / (ppb) H3/REAS FOKXUU (ppb) H4/DEAS ========= (ppb) ( L - i t i ) ========= . . . . . . . . . ========== :======== (L-at t ) :=========: ========= AS f(T> ----------F2 STRIDE 08/27/87 101.3 12.0 3.9 0.0385 0.78 0.7 0.0067 100.0 0.5 0.0046 2.8SEt03 0.2 0.0025 09/10/87 192.5 12.8 9.8 0.0511 0.78 1.8 0.0094 100.0 1.3 0.0065 2.85E*03 0.7 0.0035 OS/24/87 156.8 12.7 7.2 0.0456 0.81 1.3 0.0O86 95.1 1.0 0.0061 2.74£»03 0.5 0.0031 10/07/87 209.4 11.6 6.7 0.0320 0.78 1.1 0.0054 100.0 0.8 0.0037 2.85E+03 0.4 0.0018 10/22/87 72.8 15.7 1.3 0.0179 0.72 0.3 0.0037 110.7 0.2 0.0025 3.10E*O3 0.1 0.0014 11/12/87 98.9 16.2 3.5 0.0350 0.72 0.7 0.0075 110.7 0.5 0.0051 3.10E+03 0.3 0.0028 11/26/87 74.7 18.0 0.2 0.0029 0.70 0.1 0.0007 113.6 0.0 0.0005 3.17E»03 0.0 0.0003 12/15/87 42.6 18.6 0.2 0.0045 0.70 0.0 0.0011 113.6 0.0 0.0007 3.17E»03 0.0 0.0004 12/31/87 77.5 19.2 2.5 0.0317 0.70 0.6 0.0079 113.6 0.4 0.0054 3.17EI03 0.2 0.0028 01/14/88 46.0 21.2 2.3 0.0502 0.70 0.6 0.0137 113.6 0.4 0.0094 3.17E+03 0.2 0.0051 01/28/88 101.6 17.8 5.3 0.0524 0.73 1.3 0.0127 107.9 0.9 0.0086 3.04E+03 0.4 0.0040 02/11/88 117.3 17.9 6.5 0.0558 0.72 1.6 0.0133 110.7 1.1 0.0090 3 . 1 0 M 3 0.5 0.0046 03/03/88 86.1 18.4 6.0 0.0699 0.73 t .5 0.0174 107.9 1.0 0.0119 3.04E»03 0.5 0.0057 03/31/88 91.0 17.9 4.2 0.0457 0.72 1.0 0.0109 110.7 0.7 0.0074 3.10E+03 0.3 0.0037 F3 STRIDE 08/27/87 210.6 14.7 3.7 0.0175 0.72 0.7 0.0034 110.7 0.5 0.0023 3.10C*03 0.3 0.0013 09/10/87 242.6 13.9 ~ 8.6 0.0354 0.72 1.6 0.0065 110.7 1.1 0.0044 3.10E+03 0.6 0.0024 09/24/87 162.6 14.1 9.3 0.0573 0.75 1.8 0.0110 105.2 1.3 0.0077 2.97E»03 0.6 0.0039 10/07/87 70.6 15.2 7.0 0.0994 0.72 1.4 0.0199 110.7 1.0 0.0137 3.10EX>3 0.5 0.0069 10/22/87 128.7 16.3 6.2 0.0478 0.70 1.3 0.0100 113.6 0.9 0.0069 3 . 1 7 W 3 0.5 0.0038 11/12/87 133.3 16.2 9.7 0.0728 0.72 2.0 0.01S3 110.7 1.4 0.0107 3.1K+03 0.8 0.0058 11/26/87 110.5 18.6 6.3 0.0567 0.70 1.6 0.0142 113.6 1.0 0.0093 3.17E*03 0.6 0.0051 12/15/87 59.5 18.5 4.2 0.0705 0.72 1.0 0.0172 110.7 0.7 0.0118 3.10E+03 0.4 0.0061 12/31/87 75.8 19.0 4.8 0.0636 0.73 1.2 0.0161 107.9 0.9 0.0112 3.04E*03 0.5 0.0060 01/14/88 56.4 19.1 1.3 0.0228 0.72 0.3 0.0055 110.7 0.2 0.0039 3.10E+03 0.1 0.0021 01/28/88 215.4 16.6 7.6 0.0352 0.73 t .7 0.0079 107.9 1.2 0.0054 3.04EHX3 0.6 0.0027 02/11/88 62.2 17.2 6.3 0.1006 0.73 1.4 0.0230 107.9 1.0 0.0160 3.04E+03 O.S 0.0082 03/03/88 53.8 17.9 7.8 0.1442 0.72 1.8 0.0329 110.7 1.3 0.0233 3.10E+4J3 0.6 0.0116 03/31/88 77.9 17.1 11.8 0.1514 0.75 2.8 0.0355 105.2 1.9 0.0247 2.97E+03 1.0 0.0123 F6 STRIDE 10/22/87 113.6 12.4 30.7 0.2705 0.76 5.6 0.0494 102.6 3.7 0.0327 2.91E*03 1.7 0.0152 11/12/87 245.4 14.5 18.4 0.0750 0.78 3.8 0.0154 100.0 2.7 0.0109 2.85E+03 1.3 0.0051 11/26/87 202.2 18.4 3.0 0.0147 0.73 0.7 0.0036 107.9 O.S 0.0025 3.04EH8 0.2 0.0012 12/15/87 82.3 20.4 2.7 0.0330 0.73 0.7 0.0090 107.9 0.5 0.0062 3 . 0 4 M 3 0.2 0.0029 12/31/87 60.2 24.0 5.2 0.0866 0.66 1.5 0.0247 122.8 1.0 0.0169 3.37EM)3 0.5 0.0082 01/14/88 35.5 24.0 3.4 0.0958 0.66 1.0 0.0273 122.8 0.7 0.0187 3.37E+03 0.3 0.0078 01/28/88 ,257.4 19.8 7.1 0.0275 0.70 1.8 0.0070 113.6 1.2 0.0048 3.17E+93 0.6 0.0023 02/11/88 H.D. 22.1 6.3 — 0.69 1.8 — 116.6 1.2 - 3.23E«03 — — 03/03/88 65.1 19.8 6.8 0.1037 0.70 1.7 0.0262 113.6 1.2 0.0181 3.17Ef03 0.6 0.0086 TABLE 5.14 - R e s u l t s o f Henry's Law Co m p a r i s o n F2, F3, F6 S t r i d e Ave. 166 ========== =========: ========= :=========: :========: ========= : s====s===: : s======; :======== :=========: :=====z=s DATE KH3-N HI KH3 BY HI RATIO H2 NK3 BY H2 RATIO H3 KH3 by H3 RATIO H4 by NH3 by H4 RATIO 6AS ( • O I M / (ppb) Hl/HEAS U t i / I ) (ppb) H2/KEAS (•ol*s/ (ppb) K3/HEAS fORNUlA (ppb) H4/KEAS (ppb) ( L - i t i ) ( L - a t i ) AS f(T) F7 STRIDE 08/27/87 239.8 12.8 30.8 0.1286 0.78 5.6 0.0235 100.0 3.9 0.0164 2.85E*03 2.0 0.0082 09/10/87 244.4 10.6 52.7 0.2156 0.81 8.3 0.0338 95.1 5.9 0.0239 2.74E+03 2.9 0.0120 09/24/87 120.7 13.6 21.6 0.1793 0.78 4.2 0.0345 100.0 2.9 0.0244 2.85E+03 1.5 0.0125 10/07/87 97.3 13.9 17.7 0.1822 0.72 3.2 0.0332 110.7 2.2 0.0228 3.10E+03 1.2 0.0121 10/22/87 179.0 13.2 18.4 0.1029 0.78 3.4 0.0193 100.0 2.4 0.0135 2.85C+03 1.3 0.0070 11/12/87 193.8 13.6 29.7 0.1531 0.76 5.6 0.0289 102.6 3.9 0.0203 2.91E+03 1.9 0.0100 11/26/87 228.2 15.0 2.3 0.0100 0.75 0.0 0.0002 105.2 0.3 0.0014 2.97E+03 0.2 0.0007 12/15/87 49.2 16.0 20.3 0.4117 0.81 4.9 0.0992 95.1 3.4 0.0692 2.74E+03 1.7 0.0355 12/31/87 42.9 16.0 18.5 0.4307 0.78 4.3 0.0994 100.0 2.9 0.0688 2.85E»03 1.4 0.0335 01/14/88 43.7 14.5 23.7 0.5436 0.81 5.1 0.1174 95.1 3.6 0.0827 2.74E+03 1.8 0.0410 01/28/88 161.4 15.5 18.0 0.1117 0.78 4.0 0.0247 100.0 2.8 0.0173 2.85E»03 1.5 0.0095 02/11/88 299.4 15.5 28.4 0.0950 0.78 6.4 0.0213 100.0 4.4 0.0147 2.85E+03 2.6 0.0088 03/03/88 69.2 14.9 71.4 1.0331 0.79 15.7 0.2270 97.5 11.0 0.1583 2.80E+03 5.9 0.0847 03/3.1/88 39.6 14.9 38.4 0.9708 0.79 8.4 0.2122 97.5 5.9 0.1488 2.80£*03 2.8 0.0711 F8 STRIDE 12/15/87 30.1 19.7 0.6 0.0191 0.72 0.1 0.0049 110.7 0.1 0.0034 3.I0E+O3 0.0 0.0015 12/31/87 75.7 19.7 3.0 0.0390 0.72 0.8 0.0099 110.7 0.5 0.0070 3.10E+03 0.3 0.0038 01/14/88 50.9 20.4 3.9 0.0758 0.72 1.0 0.0200 110.7 0.7 0.0140 3.10E+03 0.4 0.0074 01/28/88 188.3 18.5 1.4 0.0073 0.72 0.3 0.0018 110.7 0.2 0.0012 3.10E+03 0.1 0.0006 02/11/88 71.2 24.0 0.5 0.0071 0.66 0.1 0.0020 122.8 0.1 0.0014 3.37E+03 0.1 0.0008 03/03/88 69.8 18.5 0.8 0.0120 0.72 0.2 0.0028 110.7 0.1 0.0020 3.10E+03 — — 03/31/88 71.3 21.7 1.1 0.0147 0.66 0.3 0.0038 122.8 0.2 0.0026 3.37E+03 0.1 0.0013 10B STRIDE 08/27/87 278.8 12.0 1.3 0.0046 0.78 0.2 0.0008 100.0 0.2 0.0006 2.85E+03 0.1 0.0002 09/10/87 283.1 11.1 3.2 0.0112 0.75 0.5 0.0017 105.2 0.3 0.0012 2.97E»03 0.1 0.0005 09/24/87 98.0 13.3 1.4 0.0141 0.75 0.3 0.0026 105.2 0.2 0.0018 2.97E+03 0.1 0.0008 10/07/87 112.0 11.4 2.0 0.0176 0.75 0.3 0.0028 105.2 0.2 0.0019 2.97E+03 0.1 0.0008 TABLE 5.15 - R e s u l t s F7, F8, of H e n r y ' s 10B S t r i d e Law C o m p a r i s o n Ave . 167 D A T E NH3-N HI NH3 BY HI R A T I O H2 NH3 BY H2 R A T I O H3 KH3 by H3 R A T I O H4 by NH3 by H4 R A T I O 8AS ( M W S / (ppb) H l / H E A S U U / D (ppb) H 2 / H E A S ( M l * * / (ppb) H 3 / H E A S F O R M U L A (ppb) H 4 / H E A S (ppb) ( L - i t i ) ( L - a t i ) A S f ( T ) BS RICHMOND 09/01/87 253.4 6.4 991.4 3.9126 0.96 121.5 0.4797 74.3 85.5 0.3375 2.24E+03 36.0 0.1421 09/15/87 75.5 8.6 1407.9 18.6564 0.93 226.3 2.9993 78.0 154.4 2.0465 2.33E+03 65.6 0.8691 09/29/87 231.8 7.4 1366.4 5.8960 0.96 196.6 0.8485 74.3 136.2 0.5878 2.24E+03 57.4 0.2478 10/13/87 102.8 8.1 1394.4 13.5610 0.93 215.6 2.0970 78.0 144.0 1.4007 2.33E+03 61.0 0.5937 11/03/87 128.9 8.9 2818.3 21.8575 0.96 491.3 3.8105 74.3 337.1 2.6144 2.24E+03 141.1 1.0946 11/17/87 N.D. 10.0 266.8 — 0.91 47.5 — 79.9 33.2 - - 2.38E+03 14.2 — 12/01/87 N.D. 12.3 31.6 — 0.8S 6.4 — 88.2 4.4 - - 2.58E+03 1.9 -12/24/87 29.1 14.9 35.5 1.2168 0.79 8.0 0.2735 97.5 5.4 0.186S 2.80E+03 2.4 0.0828 01/06/88 30.2 16.0 52.6 1.7438 0.81 12.8 0.4236 93.1 8.8 0.2930 2.74£»03 3.9 0.1294. 01/19/88 36.5 16.5 38.1 1.0431 0.78 9.1 0.2504 100.0 6.3 0.1723 2.85E«03 2.8 0.0769 02/02/88 24.1 23.8 37.5 1.5550 0.67 11.4 0.4739 119.6 7.5 0.3096 3.30£*03 3.4 0.1422 02/24/88 61.9 15.0 8.7 0.1405 0.75 1.7 0.0282 105.2 1.2 0.0201 2.97E+03 0.6 0.0090 03/15/88 334.9 13.6 13.7 0.0409 0.78 2.6 0.0079 100.0 1.9 0.0056 2.85E+03 0.9 0.0026 04/05/88 19.6 19.8 7.2 0.3643 0.70 1.8 0.0934 113.6 1.2 0.0636 3.17E+03 0.6 0.0308 09 RICHHOM 09/01/87 280.3 4.2 17593.4 62.7740 1.17 1894.3 6.7590 53.3 1390.6 4.9616 1.7IE+03 546.9 1.9312 09/15/87 79.0 5.4 11599.5 146.7584 1.14 1560.0 19.7370 55.8 1115.8 14.1171 1.77E+03 443.1 5.6067 09/29/87 118.5 4.6 18289.3 1S4.335S 1.17 2134.4 18.0115 33.3 1571.9 13.2649 1.7IEHB 621.8 5.2470 10/13/87 35.9 4.5 97381.0 2716.08 1.14 10688.B 298.1247 55.8 7892.4 220.1303 1.77E+03 3072.7 83.7010 11/03/87 72.6 5.2 28361.6 390.7305 1.14 3373.6 49.2328 53.8 2649.7 36.5045 I.77E+03 1046.3 14.4140 11/17/87 170.7 4.6 17157.6 100.5137 1.20 2011.3 11.7828 50.9 1566.7 9.1780 1.64E+03 609.9 3.5731 12/01/87 N.D. 4.7 2190.6 1.18 245.0 — 52.1 199.7 - - t.68E*03 78.1 — 12/24/88 39.8 6.2 68.7 1.7289 1.14 9.1 0.2278 55.8 7.7 0.1932 1.77E+03 3.1 0.0777 01/06/88 11.7 5.9 8816.7 730.6831 1.14 1241.6 105.7148 S3.8 927.1 78.9386 1.77E+03 373.2 31.7747 01/19/88 44.7 8.1 644.9 14.4320 1.05 107.7 2.4091 64.3 81.5 1.8229 1.99E+03 33.8 0.7569 02/02/88 34.4 7.5 9324.1 270.8809 1.08 1631.5 47.3978 61.3 1140.7 33.1395 1.91E+03 468.2 13.6033 02/24/88 N.D. 6.9 12082.9 1.09 1980.9 — 59.9 1389.2 - - 1.88E*03 565.5 — 03/15/88 205.7 6.3 23771.1 115.5444 1.11 3724.0 18.1012 58.5 2572.0 12.5016 1.84E+03 1114.5 5.4171 04/05/88 N.D. 9.5 2129.4 0.96 401.7 — 74.3 271.2 - 2.24E+03 121.5 — TABLE 5.16 R e s u l t s o f Henr y ' s Law C o m p a r i s o n B8, D9 Richmond 168 DATE NH3-N HI KH3 BY HI SAT 10 H2 HH3 BY H2 RATIO H3 KH3 by K3 RATIO H4 by NH3 by H4 RATIO SAS d o l t s / (ppb) Hl/HEAS U t i / I ) (ppb) H2/HEAS d o l t s / (ppb) H3/HEAS FORKUU (ppb) H4/HEAS (ppb) ( L - i t i ) AS HI ) ========== ======== ========= ;========= ======= ========= :=========: :======== ======== ========= :=======: :========: :=========: :=======• C6 RICHMOND 09/01/87 141.1 5.7 304.0 2.1549 1.08 36.8 0.2607 61.3 28.3 0.2008 1.91E*03 11.4 0.0811 09/15/87 77.6 6.5 437.9 5.6428 1.05 59.1 0.7618 64.3 44.6 0.5746 1.99E*03 i a . i 0.2333 09/29/87 266.2 6.0 62.3 0.2342 1.05 7.7 0.0289 64.3 5.8 0.0218 1.99E+03 2.4 0.0089 10/13/87 119.2 5.6 76.4 0.6404 1.11 9.4 0.0789 58.5 7.3 0.0615 1.84E+03 2.9 0.0247 11/03/87 74.8 6.1 423.1 5.6584 1.08 54.3 0.7259 61.3 41.8 0.5592 1.91E«03 16.7 0.2234 11/17/87 73.4 6.2 14.1 0.1924 1.08 1.8 0.0245 61.3 1.4 0.0196 I.91EMJ3 0.6 0.0080 12/01/87 N.D. 10.6 12.2 — 0.91 2.3 -- 79.9 1.6 — 2.38E+03 0.7 — 12/24/87 14.4 16.5 15.0 1.0441 0.79 3.7 0.2599 97.5 2.5 0.1769 2.80EHI3 1.1 0.0786 01/06/88 11.5 15.5 9.5 0.8252 0.78 2.1 0.1869 100.0 1.5 0.1276 2.85£*03 0.7 0.0575 01/19/88 62.6 13.6 19.8 0.3162 0.84 4.3 0.0680 90.4 3.0 0.0474 2.63C*03 1.3 0.0210 02/02/88 14.9 14.5 25.4 1.7072 0.81 5.7 0.3851 95.1 3.9 0.2596 2.74E*03 1.7 0.1153 02/24/88 40.6 12.3 35.5 0.8743 0.81 6.7 0.1658 95.1 4.6 0.1132 2.74E+03 2.0 0.0503 03/15/88 118.9 8.7 59.0 0.4962 0.99 9.8 0.0823 70.8 7.3 0.0610 2.15E+03 — — 04/0S/88 14.2 13.6 5.8 0.4073 0.84 1.3 0.0894 90.4 0.9 0.0611 2.63E+03 0.4 0.0288 67 RICHMOND 09/01/87 271.2 5.8 922.1 3.4006 1.02 108.6 0.4006 67.4 79.0 0.2913 2.07E+03 32.6 0.1200 09/15/87 80.5 6.4 1131.0 14.0527 0.99 14S.5 (.8081 70.8 102.9 1.2782 2.I5E*03 43.1 0.5351 09/29/87 173.1 6.5 1524.3 8.8054 1.02 203.2 1.1736 67.4 146.5 0.846S 2.07E+03 61.0 0.3524 10/13/87 124.8 6.2 1489.0 11.9264 I.OS 195.8 1.S681 64.3 142.9 1.1448 1.99E»03 S8.7 0.4699 11/03/87 74.4 6.9 2488.8 33.4312 1.02 354.4 4.7607 67.4 253.8 3.4096 2.07E«03 10S.4 1.4153 11/17/87 18.8 7.9 1781.0 94.7868 l.OS 299.5 15.9388 64.3 218.0 11.6000 1.99E+03 89.3 4.7S38 12/01/87 N.D. 10.4 136.7 — 0.94 26.1 ~ 76.1 18.6 — 2.2K+03 7.9 — 12/24/87 10.6 16.S 18.2 1.7217 0.81 4.5 0.4300 93.1 3.2 0.2993 2.74E+03 1.4 0.1335 01/06/88 25.2 9.6 97.4 3.8659 0.99 17.3 0.68S1 70.8 13.2 0.5228 2.15E+03 5.5 0.2170 01/19/88 20.0 10.1 64.6 3.2263 0.96 11.6 0.5804 74.3 8.8 0.4381 2.24E+03 3.7 0.1850 02/02/88 N.D. 12.0 51.8 — 0.90 10.7 — 81.9 7.6 — 2.42E+03 3.3 — 02/24/88 - 10.8 53.3 0.96 10.2 74.3 7.7 — 2 . 2 4 M 3 3.3 — 03/15/88 186.3 9.5 67.0 0.3594 0.96 11.4 0.0613 74.3 8.5 0.0458 2.24E+03 3.9 0.0208 04/05/88 N.D. 16.5 2.4 — 0.76 O.S — 102.6 0.4 — 2.9IE*03 — — TABLE 5.17 - R e s u l t s o f Henry ' s Law Co m p a r i s o n C6, G7 Richmond 169 ========= ======== ========= :=========: ========= ========= :=========: ========= ========= :=========: :=======: ========== :=========: :=======: DATE NH3-N HI NH3 BY HI RATIO H2 NH3 BY H2 RATIO H3 NH3 by H3 RATIO H4 by NH3 by H4 RATIO 6AS d o l t s / (ppb) Hl/KEAS ( a t i /X) (ppb) H2/KEAS d o l e s / (ppb) K3/REAS FORMULA (ppb) H4/NEAS ========== (ppb) (L-at t) ========= ========= ========= ========== ========= (L -a t i ) :=========: AS f(T) :=========: :=======: D.55 RICHMOND 09/01/87 156.8 5.2 3201.8 20.4204 1.08 369.2 2.3347 61.3 273.8 1.7463 1.91E+03 112.1 0.7149 09/15/87 N.D. 5.7 2001.8 — 1.08 252.8 — 61.3 186.6 — 1.91E+03 76.4 — 09/29/87 85.3 5.0 2427.5 28.4721 t . l l 275.3 3.2285 58.5 207.7 2.4366 1.84E+03 84.3 0.9892 10/13/87 101.8 5.2 2477.5 24.3264 1.11 290.8 2.8555 58.5 218.1 2.1418 1.84E+03 88.2 0.8660 11/03/87 125.5 6.1 2843.3 22.6495 1.11 392.8 3.1290 58.5 298.5 2.3777 1.84E*03 119.4 0.9315 11/17/87 19.3 6.9 1563.3 80.8784 1.11 245.3 12.6891 58.5 183.3 9.5967 1.84EI03 75.0 3.8809 12/01/87 N.D. 9.5 996.4 — 0.96 183.1 — 74.3 126.9 — 2.24E+03 53.6 — 12/24/87 14.7 10.2 851.2 57.9230 0.99 171.9 11.6991 70.8 122.9 8.3604 2.15E+03 52.0 3.5409 01/06/88 36.6 8.3 1541.5 42.1301 1.03 267.6 7.3134 65.8 194.8 5.3245 2.03E+03 77.4 2.1160 01/19/88 77.4 9.6 923.8 11.9421 0.99 176.3 2.2791 70.8 124.9 1.6149 2.15E+03 52.0 0.6720 02/02/88 29.2 9.7 500.4 17.1148 0.93 91.3 3.1230 78.0 62.1 2.1244 2.33£»03 26.8 0.9169 02/24/88 — 8.2 999.9 — 0.99 160.0 ~ 70.8 115.5 — 2.15E+03 46.6 ~ 03/13/88 74.1 10.3 440.8 5.9477 0.93 84.4 1.1384 78.0 58.3 0.7866 2.33E»03 26.9 0.3635 04/05/88 93.8 14.0 41.3 0.4400 0.82 8.9 0.0943 92.7 6.2 0.0664 2.68E+03 3.0 0.0315 B.33 RICHMOND 09/01/87 203.7 4.7 2701.7 13.2611 1.08 273.5 1.3423 61.3 206.7 1.0146 1.91E+03 83.6 0.4105 09/15/87 N.D. 5.3 2922.7 — 1.11 346.8 — 58.5 264.8 — 1.84E+03 106.2 — 09/29/87 N.D. 5.2 1991.4 — 1.11 227.1 — 58.5 173.3 — 1.84E+03 70.7 — 10/13/87 171.1 S.6 977.1 5.7103 1.08 117.1 0.6842 61.3 88.5 0.5170 1.91E+03 35 .8 0.2090 11/03/87 29.6 5.7 1272.9 43.0637 1.14 161.4 5.4398 55.8 129.9 4.3947 1.77E+03 51.9 1.7563 11/17/87 52.4 6.5 1405.2 26.8419 1.11 200.9 3.8372 58.5 156.7 2.9941 1.84E+03 63.3 1.2096 12/01/87 N.D. 8.4 393.9 — 1.05 67.3 — 64.3 51.4 — l .99£»03 21.1 — 12/24/87 20.4 13.8 129.6 6.3586 0.90 30.6 1.5033 81.9 21.8 1.0676 2.42E+03 9.7 0.4739 01/06/88 38.2 12.9 153.2 4.0150 0.90 33.6 0.8807 81.9 24.0 0.6301 2.42E+03 10.7 0.2799 01/19/88 31.5 14.5 99.7 3.1678 0.78 21.2 0.6732 100.0 14.4 0.4588 2.85E+03 6.6 0.2092 02/02/88 17.0 14.5 42.2 2.4780 0.84 9.6 0.5626 90.4 6.8 0.3971 2.63E«03 3.0 0.1785 02/24/88 — 11.6 37.3 ~ 0.88 6.8 — 83.9 5.2 - 2.47E+03 2.3 — 03/15/88 58.6 10.9 17.4 0.2963 0.87 3.0 0.0503 86.0 2.2 0.0374 2.52E»03 1.0 0.0164 04/05/88 — 17.1 3.1 — 0.79 1.2 — 97.5 0.9 — 2.B0E+03 — — TABLE 5.18 - R e s u l t s o f He n r y ' s Law C o m p a r i s o n D.55, B.53 Richmond 170 DATE HK3-N H I KK3 BY HI RATIO H2 NH3 BY H2 RATIO H3 RH3 by H3 RATIO H4 by NH3 by H4 RATIO SAS ( i o l « s / (ppb) Hl/HEAS ( a t i / I ) (ppb) H2/NEAS ( I O I K / (ppb) H3/HEAS rtKHUU (ppb) H4/HEAS (ppb) ( l - i t i ) ( L - j U l AS f(T) PI PREMIER 08/20/87 96.4 6.9 3644.9 09/03/87 81.6 7.2 5397.4 09/17/87 184.6 6.8 3193.2 10/01/87 111.3 7.3 2547.0 10/15/87 75.4 8.0 2425.3 11/05/87 141.6 8.1 2560.8 11/19/87 84.3 8.8 1646.5 12/03/87 17.9 9.6 1970.3 12722/87 42.7 10.6 2502.7 01/05/88 63.8 10.2 3096.7 01/20/88 45.1 9.8 2893.9 02/04/88 58.9 8.8 3054.8 02/23/88 134.5 9.5 2246.6 03/17/88 82.8 7.9 3152.4 04/07/88 45.3 9.7 1446.2 08/20/87 145.0 7.2 4098.9 09/03/87 86.0 6.6 6008.2 09/17/87 174.5 6.0 4545.6 10/01/87 K.D. 6.4 4571.2 10/15/87 112.5 7.0 3545.2 11/05/87 191.1 6.6 3900.3 11/19/87 48.4 7.4 2283.4 12/03/87 74.0 9.9 1511.7 12/22/87 44.3 11.2 1999.5 01/05/88 143.7 8.4 3433.7 01/20/88 32.2 8.8 2622.4 02/04/88 46.8 9.7 3064.3 02/23/88 43.1 9.3 2081.5 03/17/88 104.6 8.8 2905.6 04/07/88 29.7 10.8 703.9 37.7923 66.1317 17.2958 22.8779 32.1572 18.0882 19.5323 110.1788 58.5619 48.5514 64.1195 51.8665 16.7060 38.0492 31.9009 1.02 545.9 5.6598 67.4 371.7 1.05 864.2 10.5890 64.3 601.8 1.08 501.3 2.7156 61.3 355.9 1.02 402.6 3.6164 67.4 275.9 1.02 421.8 5.5926 67.4 288.1 1.03 455.3 3.2162 65.8 313.6 1.02 312.8 3.7109 67.4 215.0 0.99 390.3 21.8239 70.8 266.5 1.00 570.4 13.3479 69.1 385.4 0.99 655.9 10.2836 70.8 447.0 1.03 617.4 13.6792 65.8 430.1 1.02 578.3 9.8189 67.4 398.9 1.03 457.9 3.4053 65.8 323.1 1.05 547.8 6.6124 64.3 385.8 1.02 296.1 6.5325 67.4 208.2 P2 PREMIER 1.05 655.5 4.5190 64.3 457.0 1.08 912.4 10.6098 61.3 649.6 1.11 636.9 3.6501 58.5 463.1 1.08 672.1 — 61.3 479.5 1.08 S74.2 5.1052 61.3 407.5 1.08 593,6 3.1062 61.3 421.7 1.06 379.9 7.8485 62.8 270.8 0.99 303.6 4.1038 70.8 211.2 0.97 465.7 10.5134 72.5 309.0 1.05 623.8 4.3411 64.3 447.7 1.02 486.6 15.1250 67.4 342.5 1.02 633.7 13.5485 67.4 441.1 1.00 395.4 9.1836 69.1 281.0 1.02 539.6 5.1598 67.4 379.4 0.96 146.0 4.9174 74.3 102.0 3.8544 7.3737 1.9279 2.4780 3.8198 2.2149 2.5507 14.8996 9.0183 7.0077 9.5305 6.7733 2.4025 4.6564 4.5917 2.07E+03 1.99E+03 1.91E+03 2.07E+03 2.07E*03 2.03E+03 2.07E+03 2.15E+03 2.I1E+03 2.15E+03 2.03E+03 2.07E+03 2.03E+03 1.99E+03 2.07E+03 159.1 252.8 148.6 116.6 122.4 132.4 91.7 114.9 164.3 192.3 174.4 172.2 138.1 166.9 89.3 1.6501 3.0979 0.8048 1.0477 1.6231 0.9354 1.0881 6.4229 3.8435 3.0157 3.8642 2.9241 1.0273 2.0148 1.9697 28.2589 69.8636 26.0485 31.5206 20.4100 47.1801 20.4338 4S.1436 23.8962 81.5086 65.5094 48.3383 27.7838 23.7070 3.1509 7.5535 2.6538 3.6232 2.2067 5.5942 2.8544 6.9760 3.1160 10.6443 9.4293 6.5267 3.6283 3.4361 1.99EMJ3 1.91E+03 1.84E+03 1.91E+03 1.91E+03 1.9IE*03 1.95EM73 2.15E*03 2.19£»03 1.99E+03 2.07E+O3 2.07£tO3 2.1IE*03 2.07E+O3 2.24E+03 197.1 276.7 200.5 203.6 172.4 177.5 114.9 91.8 134.8 190.9 144.0 189.8 112.3 1.3591 3.2177 1.1492 1.5325 0.9288 2.3748 1.2406 3.0438 1.3284 4.4758 4.0580 2.6073 TABLE 5.19 - R e s u l t s o f Henry's Law C o m p a r i s o n P I , P2 P r e m i e r S t . 171 u n d e r p r e d i c t i o n i n s o l u b i l i t y . In Matsqui L a n d f i l l , t h i s method o v e r p r e d i c t s NH^-N gas by an average range of 30 to 60 f o l d , when F8 Matsqui i s not c o n s i d e r e d . F8 Matsqui i s a b i t of an anomaly, s i n c e i t had a very low ammonia (< 2.0 mg/L) l e a c h a t e , but s t i l l e x h i b i t e d high NH^-N i n the gas. T h i s may be due to l a t e r a l m i g r a t i o n of higher NH^-N gases from higher ammonia areas of the l a n d f i l l . In S t r i d e Ave, much l i k e i n F8 Matsqui, t h i s method c o n s i s t e n t l y u n d e r p r e d i c t s NH^-N c o n c e n t r a t i o n s by over 10 f o l d . Again, these sampling w e l l s e x h i b i t e d low NH^-N l e a c h a t e values and higher than expected NH^-N gas v a l u e s . Even though t h i s method s t i l l u n d e r p r e d i c t s S t r i d e Ave. values, i t approaches the c l o s e s t agreement of the four methods f o r p r e d i c t i n g S t r i d e Ave. gas v a l u e s . Because of the extreme heterogeneous nature of Richmond l a n d f i l l , t h i s method g r o s s l y o v e r p r e d i c t s and u n d e r p r e d i c t s NH^-N gas c o n c e n t r a t i o n s of up to 2600 and 25 r e s p e c t i v e l y . Some w e l l s do show a r e l a t i v e agreement with H 1, notably B8,C6 and B.53 w e l l s . The r a t i o i n Premier S t . l a n d f i l l , showed a c o n s i s t e n t o v e r p r e d i c t i o n of NH^-N gas c o n c e n t r a t i o n s by 2 0 - f o l d or g r e a t e r . 5.6.2.2. MOLE FRACTION METHOD As mentioned p r e v i o u s l y , t h i s method i s used most commonly for e x p r e s s i n g Henry's law by the below r e l a t i o n s h i p : H 2 = Pa/Xa ( i i i ) Where Pa = P a r t i a l pressure of gas above the aqueous s o l u t i o n (atm) 172 Xa = Mole f r a c t i o n of chemical a in aqueous s o l u t i o n Two sources of Henry's law data were averaged and regressed to o b t a i n an equation used to p r e d i c t at a given temperature. 2 The r e s u l t i n g r e g r e s s i o n equation.has a % C.V. of 3 % and r of 0.996236. P r e s e n t a t i o n of the data and r e g r e s s i o n equation i s l o c a t e d i n Appendix B.11. . P o t e n t i a l i n a c c u r a c i e s and e r r o r s i n t h i s method may be due to the f o l l o w i n g : 1. The l a r g e v a r i a t i o n (over 30 %) between the l i t e r a t u r e values coupled with the v a r i a t i o n i n r e g r e s s i o n parameters may c o n t r i b u t e s i g n i f i c a n t l y to e r r o r . 2. L i t e r a t u r e source c o n s t a n t s were c a l c u l a t e d from pure-, water measurements. : 3. Roundoff e r r o r s from spreadsheet c a l c u l a t i o n s . The r a t i o s of p r e d i c t e d vs. measured f o r t h i s technique are g e n e r a l l y about 3 times l e s s than H 1 r a t i o s which means t h i s method agrees b e t t e r with higher NH^-N l e a c h a t e w e l l s and l e s s e r with low NH^-N sampling w e l l s . 5.6.2.3. GIBBS FREE ENERGY METHOD T h i s method was adapted from Stumm and Morgan (1981) who used standard entropy and enthalpy data to c a l c u l a t e the e q u i l i b r i u m constant between the aqueous and gas phase. T h i s entropy and enthalpy data are taken from the thermodynamic l i t e r a t u r e and c o r r e c t e d f o r temperature dependency. The b a s i c exothermic e q u i l i b r i u m r e a c t i o n between NH3|aq 173 and NH3|g can be estimated by f i r s t c a l c u l a t i n g the f r e e energy change with the entropy (H) and enthalpy data (S) (equation ( v i ) ) and s u b j e c t i n g t h i s to equation (y) : AGo = H - TAS ( iv ) In H 3 = - AG 0 / RT (v) Where AG° i s the Gibbs Free Energy An example of t h i s method i s l i s t e d i n Appendix B.12. P o t e n t i a l e r r o r s i n t h i s method can r e s u l t from the f o l l o w i n g : 1. Stumm and Morgan q u a l i f y i n t h e i r d i s c u s s i o n on t h i s method that the q u a l i t y of thermodynamic data i s \" h i g h l y v a r i a b l e \" and they \"do not c l a i m to have c r i t i c a l l y s e l e c t e d the best data a v a i l a b l e . \" A l l data chosen i s v a l i d at standard s t a t e temp, and pressure which may not be true i n l a n d f i l l s where i n t e r n a l p r e s s u r e s do' exceed 1 atm. 2. The thermodynamic data was again c a l c u l a t e d using a d i s t i l l e d water s o l u t i o n . The r e s u l t s i n Tables 5.12 through 5.19 i n d i c a t e H 3 p r e d i c t s r a t i o s that are 2 - f o l d l e s s than and 6 - f o l d l e s s than H 1. 5.6.2.4. SOLUBILITY-EQUILIBRIUM METHOD The l a s t method compared i s used q u i t e o f t e n i n the dynamic modelling of atmospheric ammonia. The method used by t h i s author was adapted from the study by Hales and Drewes (1.979). T h i s constant i s dimensionless and r e l a t e s the m o l a r i t y of both the aqueous and. gas phase in the below equation: H 4 = [NH 3|aq]/[NH 3|g] 174 The constant i s temperature dependent and was r e g r e s s e d by Hale and Drewes (1979) f o r 30 data p a i r s to o b t a i n an expression 2 f o r c a l c u l a t i n g U^. T h i s equation has a C.V. of 10 % and an r was never documented. Hale and Drewes (1979) do mention that e r r o r s i n t h i s equation can become e x c e s s i v e when d e a l i n g with -9 aqueous m o l a r i t i e s that are l e s s than 10 . Small c o n c e n t r a t i o n s of 0.1 N s u l f u r i c a c i d were a l s o added to the ammonia s o l u t i o n to determine how NH^-N s o l u b i l i t y changes with a d d i t i o n of strong a c i d ( i e , s i m u l a t i n g a c i d r a i n e f f e c t s ) . The authors a l s o s u b j e c t e d the system to normal atmospheric l e v e l s of CC^ to measure the response CC^ had on H^. The r e g r e s s i o n equation and a sample c a l c u l a t i o n of t h i s method i s presented i n Appendix B. 13. As expected the e r r o r s of t h i s method are a . r e s u l t o f : 1. High C.V. i n the Henry's constant equation c o u l d r e s u l t in l a r g e v a r i a t i o n s , e s p e c i a l l y i n the very d i l u t e s o l u t i o n s . 2. Measurements were done i n pure d i s t i l l e d water, which as mentioned before, i s not i n d i c a t i v e of a l e a c h a t e system. A l s o t h e i r measurements done with CC^ i n d i c a t e l a r g e changes i n s o l u b i l i t y r e s u l t i n g i n much g r e a t e r than predicted, gas. phase NH^. T h i s w i l l be d i s c u s s e d i n more d e t a i l l a t e r . I n s p e c t i o n of the r e s u l t s i n Tables 5.12 through 5.19 i n d i c a t e that H^ f u r t h e r u n d e r p r e d i c t s S t r i d e Ave. data while agreeing more c l o s e l y with some Richmond and Matsqui data. H^ a l s o agrees q u i t e f a v o r a b l y with Premier St. data where r a t i o s are g e n e r a l l y l e s s than 3.0. The r a t i o s c a l c u l a t e d by H. are 175 g e n e r a l l y 2 - f o l d l e s s than H^ r a t i o s and 1 2 - f o l d l e s s than H 1 r a t i o s . 5.6.2.5. SUMMARY OF RESULTS A t a b l e summarizing the major trends of the data presented in t a b l e s 5.12 through 5.19 i s presented below: TABLE 5.20 - Summary Ma t r i x of the Average Range of R a t i o s (Predicted/Measured) found i n each l a n d f i l l . LANDFILLS H1 • HENRY 1S CONSTANTS H 2 H 3 H 4 MATSQUI 30-60 1 0-20 5-10 2.5-5.0 STRIDE 0.05-0.5 0.02-2.0 0.01-0.1 0 .005-0.05 RICHMOND 0.3-100 0. 1-35 0.05-20 0 .025-10 PREMIER ST. 1 5-60 5-20 2.5-10 1 .3-5.0 H 1 = C o r r e c t e d Vapor Pressure Method H 2 = Mole F r a c t i o n Method H 3 = Gibbs Free Energy Method H. = S o l u b i l i t y - E q u i l i b r i u m Method (Note: Values i n matrix are predicted/measured NH3-N gas r a t i o s ) I n s p e c t i o n of Tables 5.12 through 5.20 b r i n g up some i n t e r e s t i n g r e l a t i o n s h i p s between the d i f f e r e n t c o n s t a n t s and l a n d f i l l s that are worth mentioning below: i . That documented Henry's constants are not a p p l i c a b l e to high ammonia (> 250 mg/L NH^-N) with high pH's (>6.6) and low ammonia l e a c h a t e s (< 20 mg/L NH--N) that have low pH's (<6.2). 176 Many sample w e l l s that f i t under t h i s l a b e l are ones that were subjected t o high volume r a i n water d i l u t i o n of t h e i r l e a c h a t e . In c o n t r a s t , S t r i d e Ave. w e l l s were not s u f f i c i e n t l y d i l u t e d and s t i l l e x h i b i t e d c o n s i s t e n t l y low NH^-N l e a c h a t e pH throughout the 8 month study p e r i o d . C l o s e s t agreement to a r a t i o of 1.0 i n S t r i d e Ave. data r e s u l t e d from the H 1 method that s t i l l u n d e r p r e d i c t e d the r a t i o 1 0 - f o l d . 2. The c a l c u l a t e d r a t i o s c o u l d be s u b j e c t e d not only to e r r o r s a l r e a d y d i s c u s s e d i n f o r m u l a t i n g the Henry's constants but a l s o from the a n a l y t i c a l v a r i a b i l i t y i n the pH and c o n d u c t i v i t y meters and ammonia d i s t i l l a t i o n - t i t r a t i o n technique, which determines the l e a c h a t e NH^-N c o n c e n t r a t i o n . The r e s u l t s of t h i s study agree f a v o r a b l y with another study r e c e n t l y done by Stephens et a l . (1986) on v o l a t i l e o r g a n i c s from the BKK l a n d f i l l i n West Covina, C a l i f . . The r a t i o s they found of predicted/measured c o n c e n t r a t i o n s ranged from 0.002 in v i n y l c h l o r i d e to 2.5 f o r benzene. Stephens et a l . (1986) concluded that the discrepancy of the predicted/measured values was due to one; d i s e q u i l i b r i u m between the aqueous and gas phases make Henry's Law n o n - v a l i d , or two; the low r a t i o found i n v i n y l c h l o r i d e measurements are due to a g r e a t e r p r o d u c t i o n of v i n y l c h l o r i d e (due to m i c r o b i a l degradation of TCE ?) at a g r e a t e r r a t e than the v o l a t i l i z a t i o n r a t e . The second cause i s q u e s t i o n a b l e s i n c e the v o l a t i l i z a t i o n r a t e of v i n y l c h l o r i d e i s extremely h i g h . In summary, t h i s author would use extreme c a u t i o n i n 177 a p p l y i n g documented Henry's co n s t a n t s f o r p r e d i c t i o n of gas or leachate v a l u e s i n a l a n d f i l l environment. T h i s author b e l i e v e s the data support t h i s c o n c l u s i o n . The main reason why c a u t i o n should be heeded r e s u l t s from the u n c e r t a i n t y of whether or not a l a n d f i l l system i s i n e q u i l i b r i u m between the aqueous and gas phases, which i s the fundamental assumption behind Henry's law. If one would have to choose between the 4 d i f f e r e n t Henry's constants f o r p r e d i c t i o n of gas c o n c e n t r a t i o n i n a i a n d f i l l environment, I would have to choose e i t h e r H 2 the mole f r a c t i o n method or H 4 the e q u i l i b r i u m - s o l u b i l i t y method. The main reason behind t h i s c h o i c e i s that these constants do have a r e p o r t e d v a r i a t i o n whereas the other two methods have u n c e r t a i n v a r i a t i o n . A l s o , both constants are the most f r e q u e n t l y used. Other reasons why H 1 and H^ may be suspect stem from H^'s gross o v e r p r e d i c t i o n of a l l higher NH^-N leachate w e l l s and H^'s assumption that the standard f r e e energy change occurs i n a gas that behaves i d e a l l y , which i s somewhat suspect behavior i n a v a r i e d l a n d f i l l gas mixture. 5.6.3 REASONS FOR DISCREPANCY IN PREDICTED/MEASURED RATIO In a d d i t i o n to the e r r o r - p r o n e Henry's c o n s t a n t s , there may be other more important f a c t o r s that c o n t r i b u t e to t h i s d i v e r g i n g r a t i o of p r e d i c t e d vs. measured NH^-N gas v a l u e s . These p o t e n t i a l f a c t o r s are d i s c u s s e d i n more d e t a i l below. 5.6.3.1. ANALYTICAL TECHNIQUE The main concern d e a l i n g with u n c e r t a i n t y i n the a n a l y t i c a l technique c e n t e r s around the p o s s i b l e e r r o r that low NH3-N gas 178 values may e x h i b i t . These low values were o f t e n b o r d e r i n g c l o s e to the d e t e c t i o n l i m i t of the autonanalyzer. A l s o , the l a r g e v a r i a t i o n i n data f o r d e t e r m i n a t i o n of the recovery e f f i c i e n c y i s another major u n c e r t a i n t y . Because the sampling technique d i d not p r e - f i l t e r the gas, there c o u l d be a p p r e c i a b l e amounts of N H 4 + - c o n t a i n i n g a e r o s o l s causing a p o s i t i v e i n t e r f e r e n c e i n the d e t e r m i n a t i o n of NH^-N gas. Even though I would assume t h i s c o n t r i b u t i o n to be very low, i n s p e c t i o n of the r e s u l t s i n S t r i d e Ave. l e a d me to b e l i e v e t h i s c o u l d be a s u b s t a n t i a l c o n t r i b u t o r to high measured values i n S t r i d e Ave Lower than expected NH3~N gas values i n Matsqui, Richmond and Premier S t . may one; due to s i g n a l suppression i n the autoanalyzer by i n t e r f e r e n c e s or two; e f f e c t s of high CO^ c o n c e n t r a t i o n s that may form a v o l a t i l e complex with ammonia that i s subseqently not adsorbed i n t o the b o r i c a c i d s o l u t i o n . Another p o t e n t i a l major, source of e r r o r c o n t r i b u t e d by the a n a l y t i c a l procedure i s v a r i a t i o n of pH r e s u l t s . Since the f r a c t i o n of u n i o n i z e d f r a c t i o n of ammonia i s dependent on the hydrogen ion c o n c e n t r a t i o n , accuracy of the pH meter i s a must. In c a l c u l a t i o n s done by Thurston et a l . (1974) i t can be observed that a pH i n c r e a s e of 0.5 u n i t s w i l l subsequently i n c r e a s e the f r a c t i o n of u n i o n i z e d f r a c t i o n of ammonia by over 3 - f o l d . T h i s 3 - f o l d i n c r e a s e i n the u n i o n i z e d ammonia f r a c t i o n can be t r a n s l a t e d i n t o a 3 - f o l d i n c r e a s e i n NH^-N gas c o n c e n t r a t i o n i f the system i s at e q u i l i b r i u m . 179 5.6.3.2. LANDFILL UNSATURATED ZONE The va l u e s of l e a c h a t e pH, t o t a l ammonia and s p e c i f i c c o n d u c t i v i t y may not be i n d i c a t i v e of the whole l a n d f i l l s i n c e t h e i r v a l u e s may d i f f e r c o n s i d e r a b l y from those found i n the unsaturated zone. In most i n s t a n c e s without r a i n f a l l d i l u t i o n , the c o n c e n t r a t i o n s of leachate i n the unsaturated r e f u s e pores w i l l exceed c o n c e n t r a t i o n s found i n the unsaturated zone. T h i s may be e s p e c i a l l y t r u e i n the dryer months of t h i s study, where the h i g h e s t NH3-N c o n c e n t r a t i o n s were measured. In a d d i t i o n to g r e a t e r mass c o n c e n t r a t i o n s found i n the unsaturated zone, there i s a l s o a g r e a t e r e f f e c t i v e s u r f a c e area a v a i l a b l e f o r mass t r a n s f e r i n t o the gas phase than the pseudo-planar area a v a i l a b l e f o r mass t r a n s f e r from the s a t u r a t e d zone. For i n s t a n c e , i n a h y p o t h e t i c a l l a n d f i l l , 25 ha i n area with a p l a n a r water t a b l e 10 m below the bottom of the l a n d f i l l cover, there would be .an., e f f e c t i v e , area, f o r mass t r a n s f e r of . 25,000 m assuming the l a n d f i l l had an a i r - f i l l e d p o r o s i t y of 0.10. In c o n t r a s t , the unsaturated zone would have an h y p o t h e t i c a l e f f e c t i v e area a v a i l a b l e f o r mass t r a n s f e r of 2 ' • 250,000 m . T h i s f i g u r e i s roughly 10. times the area a v a i l a b l e f o r gas phase mass t r a n s f e r i n the s a t u r a t e d zone. Both of these values w i l l become l e s s d u r i n g a c t i v e r a i n f a l l p e r i o d s s i n c e the a i r - f i l l e d p o r o s i t y may decrease. T h i s s i m p l i f i e d example i n d i c a t e s that the deeper the l a n d f i l l water t a b l e , the g r e a t e r c o n t r i b u t i o n e x i s t s i n the 180 unsaturated zone for NH^-N gas g e n e r a t i o n . 5.6.3.3. VOLUME DILUTION EFFECT Not much i s known about the p o s s i b l e mass d i l u t i o n of NH^-N gas c o n c e n t r a t i o n s from e f f i c i e n t methane and carbon d i o x i d e p r o d u c t i o n . T h i s d i l u t i o n c o u l d very w e l l be a major reason for lower than p r e d i c t e d gas value s from some w e l l s i n Matsqui and Richmond, s i n c e t h e i r CH^ and C0 2 f l u x e s were found to be much gr e a t e r than S t r i d e Ave. f l u x e s . An example of t h i s mass, or volume d i l u t i o n phenomenon i s to look at a s l a b of ref u s e 10 m X 10 m X 1 m that e x i s t s i n . a : completely anaerobic l a n d f i l l environment with a d e n s i t y of 700 3 kg/m . T h i s s l a b i s subjected to an average CH^ generat i o n r a t e of 25 mL CH 4/kg of ref u s e per day that t r a n s l a t e s i n t o a C H ^ pro d u c t i o n r a t e i n the s l a b of 1750 L CH^/slab-day. Mass t r a n s f e r of ammonia outwards from the s l a b can be estimated by using the common d i f f u s i o n equation below: Flux NH--N = (D/L) * (C, - C ) 3 1 g Where D = the, apparent d i f f u s i o n c o e f f i c e n t taken as 0.025 cm /s from Gardner (1966). L = the l i q u i d - g a s f i l m t h i c k n e s s taken as 0.01 cm 3 -C-^ = c o n c e n t r a t i o n i n l i q u i d (ug/cm ) 3 Cg = c o n c e n t r a t i o n i n gas phase (ug/cm ) If CI i s 1.0 ug/cm ( i e , 1 ppm) and Cg i s small enough to neg l e c t then: • Flux NH3.-N' = 25,000 ug/m 2-day or 0.25 gm/slab-day Flux NH3-N = .0.33 L NH 3/slab-day So the r e s u l t s i n d i c a t e a volume d i l u t i o n of ammonia gas to 181 be over 5000 f o l d in t h i s s i m p l i f i e d case. T h i s i s q u i t e s u b s t a n t i a l when one observes that d i l u t i o n due to C 0 2 gas p r o d u c t i o n was not c o n s i d e r e d i n t h i s e s t i m a t i o n . Low gas p r o d u c t i o n r a t e s causing a l e s s e r d i l u t i o n c o u l d e x p l a i n why the measured NH^-N gas values are higher than expected i n S t r i d e Ave. Conversely, one would expect to see Premier S t . l a n d f i l l gas data behave much l i k e S t r i d e Ave. s i n c e both have low gas f l u x e s . However, when studying the r a t i o s , Premier S t . was observed to e x h i b i t much g r e a t e r than measured values i n most i n s t a n c e s . The reason may not be s o l e l y due to high r e l a t i v e pH or NH^-N l e a c h a t e v a l u e s , but maybe a l s o due to v o l u m e t r i c d i l u t i o n from the gas e x t r a c t i o n system p u l l i n g atmospheric a i r i n t o the system. T h i s c o u l d be e s p e c i a l l y apparent i n the winter months as evidenced by CH 4 percentages in w e l l s P1 and P2. 5.6.3.4. LANDFILL HETEROGENIETIES Because lea c h a t e i n a sample w e l l i s only a p o i n t source of data, i t may not be r e p r e s e n t a t i v e of the surrounding l e a c h a t e due to l a n d f i l l h e t e r o g e n i t i e s . This, i s e s p e c i a l l y true i n Richmond and Matsqui l a n d f i l l s where l a r g e s p a t i a l d i f f e r e n c e s i n l e a c h a t e ammonia value s are apparent. Another p o i n t of concern i s the e f f e c t s of l a t e r a l , gas m i g r a t i o n h e l p i n g to give erroneous r e s u l t s of NH^-N gas c o n c e n t r a t i o n s not i n d i c a t i v e of i t s corresponding l e a c h a t e . As a l r e a d y mentioned, t h i s c o u l d be the case i n F8 Matsqui. 5.6.3.5. NON-EQUILIBRIUM LANDFILL ENVIRONMENT 182 The l a n d f i l l i s a dynamic environment that responds to i n t e r n a l and e x t e r n a l perturbances. However, i t c o u l d be a qu e s t i o n of whether or not the l a n d f i l l can ever e s t a b l i s h an e q u i l i b r i u m between the aqueous and gas phases s i n c e the gaseous and l i q u i d environments are f o r e v e r f l u c t u a t i n g . Some f a c t o r s that can prevent the l a n d f i l l from reaching an e q u i l i b r i u m s t a t e are noted below: 1. Large f l u x e s of biogas being generated that vary both temporally and s p a t i a l l y . 2. Internal, l a n d f i l l p r e s s u r e s that exceed standard 1 atmospheric c o n d i t i o n s . 3. Large and v a r i e d p r e c i p i t a t i o n f l u x e s observed dur i n g the r a i n y season causing chemical and b i o l o g i c a l changes. Other than these f a c t o r s there are some ammonia s p e c i f i c f a c t o r s that may cause n o n - e q u i l i b r i u m . These are l i s t e d below: 1. The pro d u c t i o n r a t e of ammonia i s much g r e a t e r than the v o l a t i l i z a t i o n or gas t r a n s f e r r a t e , causing an accumulation of un i o n i z e d ammonia i n the l e a c h a t e . I f , t h i s i s t r u e , then e q u i l i b r a t i o n of the system i s probably d i f f u s i o n r a t e l i m i t e d s i n c e there e x i s t s an ample c o n c e n t r a t i o n g r a d i e n t a v a i l a b l e f o r mass t r a n s f e r . 2. I n i t i a l e l e v a t e d c o n c e n t r a t i o n s of ammonia i n the . leach a t e have not v o l a t i l i z e d to e q u i l i b r i u m . I f t r u e , the combination of p t . #1 with t h i s mechanism would leave a much gre a t e r f r a c t i o n of NH_|aq i n the leachate than would normally be 183 p r e d i c t e d by Henry's Law,. 5.6.3.6. MASS TRANSFER LIMITATIONS There are other f a c t o r s that l i m i t the d i f f u s i o n r a t e and subsequent e q u i l i b r i u m of the aqueous and gas phases such as the chemical nature of the l e a c h a t e . Leachate i o n i c s t r e n g t h has been found to decrease the e f f e c t i v e l i q u i d d i f f u s i o n r a t e i n experiments by R a t c l i f f and H o l d c r o f t (1963) ( i n Reid and Sherwood, 1966). They found that the d i f f u s i o n c o e f f i c i e n t of C0 2 gas i n s o l u t i o n decreases l i n e r l y with an inc r e a s e i n s a l t c o n c e n t r a t i o n . T h i s phenomenon co u l d a l s o c o n c e i v a b l y occur with NH^ i n s o l u t i o n s i n c e both gases are s o l u b l e n o n - e l e c t r o l y t e s and behave somewhat a l i k e i n s o l u t i o n . Another f a c t o r that c o u l d be s u b s t a n t i a l i n a t t e n u a t i n g the d i f f u s i o n r a t e i s the a d d i t i o n of t h i n o i l f i l m s surrounding the l i q u i d t h i n f i l m that c o u l d c o n c e i v a b l y cause a weak b a r r i e r to NH^-N t r a n s f e r i n t o the gas phase.. T h i s would e s p e c i a l l y be apparent i n leachate that c o n s i s t s of l e s s dense i n s o l u b l e o r g a n i c s that f l o a t above the leach a t e at the s a t u r a t e d -unsaturated i n t e r f a c e causing a b a r r i e r to mass t r a n s f e r . T h i s e f f e c t has been modeled i n sur f a c e impoundments by i n c l u d i n g a mass t r a n s f e r c o e f f i c i e n t f o r the o i l f i l m (see E h r e n f e l d , 1986). 5.6.3.7. SOLUBILITY OF AMMONIA Other than sampling and performing the a n a l y t i c a l work, a la r g e amount of time i n t h i s study was spent t r y i n g to e x p l a i n t h i s apparent dis c r e p a n c y between the predicted/measured NH,-N 184 c o n c e n t r a t i o n s . Most of the e f f o r t s focused on understanding the s o l u b i l i t y dynamics of ammonia i n non-pure s o l u t i o n s such as l e a c h a t e . The major f a c t o r s that e f f e c t ammonia s o l u b i l i t y i n c l u d e : i o n i c s t r e n g t h , pH, p r e s s u r e , temperature and s a l i n i t y of the s o l u t i o n . In the spreadsheet c a l c u l a t i o n s f o r e s t i m a t i n g the u n i o n i z e d f r a c t i o n of NH^-N i n s o l u t i o n , e f f e c t s from temperature, pH and i o n i c s t r e n g t h were c o r r e c t e d i n the c a l c u l a t i o n s . S a l i n i t y was riot c o n s i d e r e d to be a l a r g e problem s i n c e i o n i c s t r e n g t h i n c l u d e s any e f f e c t s of s a l i n i t y (see W h i t f i e l d , 1974). Io n i c s t r e n g t h was converted to a c t i v i t y c o e f f i c i e n t s (see Appendix B.4) to c o r r e c t f o r a non i d e a l s o l u t i o n . Pressure was assumed to be 1 atm which i s c l o s e to c o r r e c t . The u n i o n i z e d f r a c t i o n was then converted i n t o the proper u n i t s f o r c a l c u l a t i o n of the p r e d i c t e d NH^-N i n gas. How much of t h i s u n i o n i z e d f r a c t i o n (NH^Iaq) may be removed from s o l u t i o n by chemical r e a c t i o n s i s a mystery. Since most u n i o n i z e d NH^-N values are a l r e a d y at low c o n c e n t r a t i o n s (< 1.0 mg/L), accumulation of c e r t a i n compounds capable of r e a c t i n g with NH^Iaq may r e s u l t i n removal of a p o r t i o n of NH^-Njaq. In t h i s s c e n a r i o , i t i s assummed that the r a t e of removal exceeds the r a t e of formation due to e q u i l i b r i u m s h i f t s . P o s s i b l e chemical r e a c t i o n s that c o u l d occur i n a l a n d f i l l l eachate to remove NH^|aq i n c l u d e the f o l l o w i n g : 1. Complexation of NH^ with other compounds that c o v a l e n t l y share the unpaired e l e c t r o n s of the n i t r o g e n atom of NH_. T h i s 185 r e a c t i o n i s commonly c a l l e d an a d d i t i o n r e a c t i o n (NRC, 1979). The types of compound a v a i l a b l e f o r t h i s r e a c t i o n are some metals such as copper and z i n c where valu e s of over 1.0 mg/L may occur. The a d d i t i o n r e a c t i o n of Cu with NH^ i s shown below: C u + + +• 4NH 3 > C u * ( N H 3 ) 4 + + 2. A s u b s t i t u t i o n r e a c t i o n of NH3 with o r g a n i c s to form an amide group. T h i s i s commonly r e f e r r e d to as \"ammonolysis\" and i s s i m i l a r to a h y d r o l y s i s r e a c t i o n . Two r e a c t i o n s are shown below that t i e up 2 moles of NH 3 while r e l e a s i n g a protonated ammonium i o n : a. Reaction w/mercuric c h l o r i d e (NRC, 1979) 2NH 3 + H g C l 2 > C l ~ + NH 4 + + ClHgNH 2 b. Reaction w/acid c h l o r i d e s (Brown W.H., 198 ) A c e t y l c h l o r i d e + 2NH 3 > Acetamide + NH 4 + + C l ~ Both chemical r e a c t i o n s c o u l d become common i n l a n d f i l l s l i k e Richmond, where leachate c o n t a i n s an abundance of c h l o r i n a t e d o r g a n i c s and c h l o r i n e compounds. 3. Complexing of the methane molecule with the ammonia molecule to form the s o l u b l e methyl ammonium ion (CH 3NH 4 +). Even though methane i s u s u a l l y n o n - r e a c t i v e with compounds at standard s t a t e c o n d i t i o n s , there c o u l d be enough random occurrances where methane bonds with ammonia to p r o v i d e a s u b s t a n t i a l removal mechanism of NH 3|aq a v a i l a b l e f o r t r a n s f e r i n t o the gas phase. 4. In a d d i t i o n to methane complexing, there may be an o p posite r e a c t i o n o c c u r r i n g between C0 9 and NH_ that i n s t e a d of 186 complexing ammonia i n s o l u t i o n , may s t r i p i t out of s o l u t i o n . T h i s r e a c t i o n i s the complexing of C0 2 and NHg to form a v o l a t i l e compound c a l l e d carbamic a c i d . T h i s carbamic a c i d may be v o l a t i l e enough to pass through the b o r i c a c i d s o l u t i o n without being adsorbed causing a n a l y t i c a l problems as w e l l . With t h i s i n mind, the e f f e c t of high C0 2 percentages may be a reason why l a r g e d i f f e r e n c e s e x i s t i n r a t i o s between p r e d i c t e d vs. measured NH^-N in Richmond and S t r i d e Ave l a n d f i l l s . In Richmond, C0 2 % can exceed 40 % while the measured values are much lower than p r e d i c t e d ; i n c o n t r a s t , S t r i d e Ave. has C0 2 % g e n e r a l l y l e s s than 20 % and a much higher r a t i o of measured versus p r e d i c t e d NH^-N gas c o n c e n t r a t i o n s . So i n Richmond l a n d f i l l , there may be a s u b s t a n t i a l removal mechanism of NH 3|aq by high C0 2 c o n c e n t r a t i o n s . 5.6.3.8. LANDFILL SINKS In a d d i t i o n to chemical s i n k s l o c a t e d w i t h i n the l e a c h a t e , there are a number of other s i n k s that c o u l d h e l p cause t h i s d i s c r e p a n c y between p r e d i c t e d and measured NH^-N c o n c e n t r a t i o n s . These are l i s t e d b r i e f l y below: 1. Adsor p t i o n of NH^|g onto l a n d f i l l r e f u s e m a t e r i a l or s o i l w i t h i n the l a n d f i l l . The r a t e at which t h i s can happen i s a f u n c t i o n of i t ' s a d s o r t i o n isotherm ( F r u e d l i c h . i s o t h e r m ) . T h i s a d s o r t i o n of NH^ i s e s p e c i a l l y p o s s i b l e i n more a l k a l i n e l a n d f i l l environments. 2. Assuming the unsaturated zone i s not a primary source of ammonia then NH_|g can be r e s o l u b l i z e d i n the unsaturated zone 187 + + f l u i d to NH 3|aq and reprotonated to NH^ . T h i s NH^ can be f u r t h e r u t i l i z e d by m i c r o b i a l a c t i v i t y or more l i k e l y , exchanged onto c o l l o i d s i n s o l u t i o n or s o l i d l a n d f i l l s u b s t r a t e . As mentioned p r e v i o u s l y , e x c e s s i v e r a i n f a l l i n f i l t r a t i o n can c r e a t e a wetting f r o n t that migrates downward i n the l a n d f i l l r e s o l u b i l i z i n g and r e p r o t o n a t i n g NH^-N gas due to i t ' s r e l a t i v e l y lower pH. 3. R e s o l u b i l i z a t i o n i n t o the a c i d i c gas condensate that e x i s t s i n s i d e the w e l l c a s i n g . 5.7 MASS FLUX EMISSION OF NH3-N GAS 5.7.1. INTRODUCTION One of the o r i g i n a l goals of t h i s t h e s i s was to get an idea of how much, i f any, n i t r o g e n i n the form of NH^-N was being emitted through the gas phase. In the f o l l o w i n g s e c t i o n , data i s presented that estimates the mass f l u x of NH^-N through two of the four study l a n d f i l l s . T h i s e s t i m a t i o n was c a l c u l a t e d by a . s i m p l i f i e d model used u n t i l t h i s time e x c u l s i v e l y f o r mode l l i n g of organic f l u x emissions from covered l a n d f i l l s . The r e s u l t i n g mass f l u x e s are then l a t e r compared to estimated f l u x e s of NH^-N in the l e a c h a t e . The model was o r i g i n a l l y conceived by Farmer et a l . (1981) to study the emission r a t e s of hexachlorobenzene by d i f f u s i o n through the l a n d f i l l cover s o i l . Thibodeaux (1981 ) m o d i f i e d t h i s model to i n c l u d e the a f f e c t s ' o f c o n v e c t i v e t r a n s p o r t through the l a n d f i l l cover. He v e r i f i e d Farmer's hexachlorobenzene r e s u l t s with c o n v e c t i o n flow and a l s o simulated the emission f l u x e s of 188 four other organic chemicals, namely benzene, c h l o r o f o r m , v i n y l c h l o r i d e and PCB ( A r o c l o r 1248). Thibodeaux then m o d i f i e d h i s own work i n 1982 by s i m u l a t i n g the emission f l u x e s of benzene by i n c l u d i n g the barometric pressure pumping e f f e c t found i n some l a n d f i l l s . The s i m u l a t i o n was c a r r i e d out by using the IBM CSMP (Continuous Systems M o d e l l i n g Program) over v a r i o u s time steps. The assumptions, l i m i t a t i o n s and d e t a i l e d aspects of these models are d i s c u s s e d i n more d e t a i l l a t e r i n the chapter. M o d e l l i n g ammonia gas f l u x e s i n s o i l s has mostly been done in the a g r i c u l t u r a l s e c t o r concerning f e e d l o t emissions and f e r t i l i z e r a p p l i c a t i o n s . U n f o r t u n a t e l y , the m a j o r i t y of t h i s ; work i s s i t e s p e c i f i c and e m p i r i c a l . 5.7.2. MODEL INTRODUCTION 5.7.2.1. FARMER'S MODEL In Farmers model, he assumed that the hexachlorobenzene wastes were t r a n s p o r t e d through the cover by d i f f u s i o n only, and that t h i s d i f f u s i o n obeyed F i c k ' s F i r s t Law of D i f f u s i o n . : - . Because the porous media had an e f f e c t on the d i f f u s i o n path l e n g t h , the ref e r e n c e d i f f u s i o n c o e f f i c i e n t (Do) was m u l t i p l i e d by a p o r o s i t y f a c t o r to the 4/3rd. T h i s model i s shown below: J (M/(L 2-T) = (De/L)*(Cs - C2) ( v i ) Where De = D o * P a 1 , 3 3 ( v i i ) 2 Where J i s the gas f l u x u s u a l l y i n gm/m -day 2 Do i s the d i f f u s i o n c o e f f i c i e n t i n a i r i n m /day De i s the e f f e c t i v e d i f f u s i o n c o e f f i c i e n t i n m /day Pa i s A i r - f i l l e d p o r o s i t y ' Cs i s s a t u r a t e d vapor c o n c e n t r a t i o n i n gm/m ^ C2 i s vapor c o n c e n t r a t i o n at l a n d f i l l s u r f a c e i n gm/m L i s t h i c k n e s s of l a n d f i l l cover i n m 189 The e f f e c t i v e d i f f u s i o n equation ( v i i ) was taken from Parton (1981) f o r d e s c r i b i n g d i f f u s i o n of ammonia gas through s o i l s . 5.7.2.2. THIBODEAUX'S MODEL In a s l i g h t m o d i f i c a t i o n to Farmer's model, Thibodeaux added a product term to the d i f f u s i o n equation that accounted f o r flow due to c o n v e c t i o n c r e a t e d from i n t e r n a l l a n d f i l l gas g e n e r a t i o n . T h i s equation i s l i s t e d below. S p e c i f i c s of how equation ( i x ) was d e r i v e d are presented i n Appendix B.14. N = (De/L)*(Ca - C ? ) * (Rexp(R)) ( i x ) (exp(R)-1) Where N i s g^s f l u x from l a n d f i l l s u r f a c e u s u a l l y i n gm/m -day Where Ca i s c o n c e n t r a t i o n of compound a (gm/m ) C 2 i s c o n c e n t r a t i o n of a at the l a n d f i l l s u r f a c e Where R = (L*v/De) (x) Where L i s l a n d f i l l cover t h i c k n e s s i n m v i s l a n d f i l l cover gas v e l o c i t y •.( i e ' n o t Darcian v e l o c i t y ) i n m/day. The (Rexp(R)) i s r e f e r r e d by t h i s author as the G - f a c t o r , (exp(R)-1) which i s a m u l t i p l y i n g f a c t o r d e s c r i b i n g the f l u x due to c o n v e c t i o n flow r e l a t i v e of the f l u x due to d i f f u s i o n . T h i s f a c t o r has been c a l l e d the l a n d f i l l gas enhancement f a c t o r by Baker and Mackay (1985). T h i s f a c t o r i n c r e a s e s with g r e a t e r l a n d f i l l gas p r o d u c t i o n , and as found i n t h i s study and other l i t e r a t u r e , the f a c t o r can exceed 6.0 f o r a normal l a n d f i l l environment. In r e a l i t y , equation ( i x ) i s the same as Farmer's model equation ( v i ) except i t i s m u l t i p l i e d by the G - f a c t o r . So the 190 r e l a t i v e d i f f e r e n c e s between Farmer's and Thibodeaux's model i s that Farmer's model only s o l v e s f o r systems without gas g e n e r a t i o n where d i f f u s i o n i s the c o n t r o l l i n g t r a n s p o r t process, while Thibodeaux's model i s a combined d i f f u s i o n - c o n v e c t i o n f l u x model 5.7.2.3. ASSUMPTIONS FOR MODELS A. Assume gas phase i s s a t u r a t e d with r e s p e c t to the compound i n q u e s t i o n . B. Thibodeaux model assumes steady s t a t e d i f f u s i o n a l and . c o n v e c t i v e t r a n s p o r t . C. Thibodeaux model assumes i n f i n i t e source of generated gas e x i s t s at e l e v a t e d p r e s s u r e s j u s t under the base of the l a n d f i l l cover. D. Thibodeaux model used assumes a constant l a n d f i l l gas p r o d u c t i o n r a t e and no b u i l d - u p of i n t e r n a l l a n d f i l l gas. p r e s s u r e s . E. Assumes gas i s behaving i n a u n i d i r e c t i o n a l flow with n e g l i g i b l e r e a c t i o n of the compound while being t r a n s p o r t e d . F. A l l d i f f u s i o n r e s i s t a n c e i s i n the s o i l and none i n the a i r boundary l a y e r at the s u r f a c e of the l a n d f i l l cover. G. Thermal g r a d i e n t s are assumed to have no e f f e c t on the f l u x r a t e . H. No a d s o r p t i o n , degradation or chemical exchange i s assumed to occur i n the cover s o i l . I. Model i s s o l v e d f o r a s i n g l e - c e l l e d l a n d f i l l with the proper boundary c o n d i t i o n s . 191 5.7.2.4. LIMITATIONS TO MODEL When d e a l i n g with an i n o r g a n i c r e a c t i v e molecular s p e c i e s l i k e ammonia, there are some o v e r l y i n g l i m i t a t i o n s to a p p l y i n g a model that has only been t e s t e d on organic vapors. Some of these l i m i t a t i o n s are l i s t e d below: A. Baker and Mackay (1985) mention i n t h e i r e v a l u a t i o n of s u r f a c e emission models, that the Thibodeaux model i s unsolvable f o r organic chemicals with vapor pre s s u r e s g r e a t e r than 1 atm. In many r e s p e c t s the vapor pressure of ammonia exceeds 1 atm, but because of the non-ideal nature of the s o l u t i o n and gas, t h i s vapor pressure i s probably much l e s s than 1 atm.. B. Model only accounts f o r one-dimensional v e r t i c a l movement of gas and does not take i n t o account l a t e r a l emissions of gas i n a r e a - f i l l t y p e - l a n d f i l l s ( i e , Richmond). C. Model does not take i n t o account any thermal c o n t r i b u t i o n to convection flow and temperature dependence of the d i f f u s i o n c o e f f i c i e n t . D. One must assume that the NH^-N c o n c e n t r a t i o n s measured are r e f l e c t a n t of the c o n c e n t r a t i o n at the base of the l a n d f i l l cover, t h i s may not always be the case. • E. Assumes the gas component to be i n s t a n e o u s l y mixed and d i s p e r s e d once at the l a n d f i l l s u r f a c e , so the c o n c e n t r a t i o n of C 2 i s e s s e n t i a l l y zero. Because NH^-N i s u b i q u i t o u s i n the atmosphere, I d i d not assume t h i s to be zero, but i n s t e a d assumed 3 C 2 to.be 20 ug/m , which i s a common c o n c e n t r a t i o n found i n the atmosphere around urban areas. There c o u l d be l a r g e 1 92 u n c e r t a i n t i e s i n t h i s assumption. F. Model does not take i n t o account any d i f f u s i o n t r a n s p o r t to the s u r f a c e by l i q u i d i n the s o i l pores. Because the d i f f u s i o n c o e f f i c i e n t s are much l e s s i n water than gas, t h i s was assumed to be n e g l i g i b l e . However, t h i s c o u l d become an important mode of t r a n s p o r t when the cover i s water logged d u r i n g high p r e c i p i t a t i o n p e r i o d s . g. Model does not take i n t o account any b u i l d - u p of i n t e r n a l l a n d f i l l gas pressure due to i n t e r n a l gas p r o d u c t i o n . The updated 1982 model by Thibodeaux does account f o r i n t e r n a l pressure b u i l d - u p and i t ' s d e r i v a t i o n i s a l s o l i s t e d i n Appendix B. 1 4. -. 5.7.3. . MODEL RESULTS OF LANDFILL NH3~N GAS FLUXES 5.7.3.1. INTRODUCTION Input parameters common to both Farmer and Thibodeaux's models are : t o t a l and a i r - f i l l e d p o r o s i t y , r e f e r e n c e d i f f u s i o n c o e f f i c i e n t , l a n d f i l l cover t h i c k n e s s and c o n c e n t r a t i o n of NH3-N gas at base of l a n d f i l l cover. A d d i t i o n a l input parameters f o r Thibodeaux's model i n c l u d e : r e f u s e d e n s i t y , t h i c k n e s s of r e f u s e f i l l and gas g e n e r a t i o n r a t e . These three parameters are combined with p o r o s i t y to get an i n t e r n a l gas v e l o c i t y which i s then s u b j e c t e d to a c a l c u l a t i o n to get R. Once R i s found, then the G - f a c t o r i s e a s i l y c a l c u l a t e d . Sample c a l c u l a t i o n s f o r t h i s procedure i s l i s t e d i n Appendix B.15. A l l c a l c u l a t i o n s were done using a LOTUS '1-2-3 spreadsheet. Premier S t . l a n d f i l l was not i n c l u d e d i n the model runs 193 s i n c e the sample w e l l s , P1 and P2 were l o c a t e d i n an area whose su r f a c e was j u s t a f r a c t i o n of the l a n d f i l l s u r f a c e . A l s o , the cover c h a r a c t e r i s t i c s at t h i s l a n d f i l l were very heterogeneous and never f u l l y understood. Matsqui L a n d f i l l was not i n c l u d e d i n the model runs because no documented lea c h a t e f l u x data of t h i s l a n d f i l l was a v a i l a b l e . The standard parameters used f o r c a l c u l a t i n g gas f l u x e s of ammonia were co n s i d e r e d to be r e p r e s e n t a t i v e of that p a r t i c u l a r l a n d f i l l , through p r e v i o u s documentation or from d i r e c t o b s e r v a t i o n i n t h i s study. For example, i f one looks at Table 5.21 which l i s t s a l l the parameters chosen, one n o t i c e s a l a r g e d i f f e r e n c e i n i n t e r n a l gas genera t i o n r a t e s between S t r i d e Ave. and Richmond L a n d f i l l . T h i s i s mainly due to> the assumption made a l r e a d y that S t r i d e Ave has very low gas genera t i o n c a p a c i t y mostly a r e s u l t of i t ' s advanced age. Richmond i s much younger: and e x h i b i t s gas values much c l o s e r to documented gas pro d u c t i o n r a t e s i n l a n d f i l l s of a comparable age. The r e f e r e n c e gas d i f f u s i o n c o e f f i c i e n t of NH^ i n a l a n d f i l l 2 gas mixture was chosen at 1.750 m/day f o r the three reasons mentioned below: • 1. Binary gas c o e f f i c i e n t s f o r a l l . major l a n d f i l l gases are 2 i n the range of 1.25 to 2.00 m /day ( F i n d i k a k i s and L e c k i e , 1979). 2 2. A Do of 1.987 m /day was re p o r t e d i n R e i d a n d Sherwood (1966) f o r the N 2-NH 3 b i n a r y system. 2 3. A Do of 1.598 m/day was mentioned i n Parton (1981) as 194 being a r e p r e s e n t a t i v e d i f f u s i o n c o e f f i c i e n t of NH^ i n s o i l s . TABLE 5.21 - Standard Values Used For M o d e l l i n g NH^-N Gas Emissions From L a n d f i l l s . Parameter S t r i d e Ave. Richmond D i f f u s i o n c o e f f i c i e n t 1.750 m 2/day 1 .750 T o t a l P o r o s i t y 0.30 0.50 A i r - f i l l e d p o r o s i t y 0.20 0,40 L a n d f i l l cover Thickness 2.0 m 1.5 I n t e r n a l Gas V e l o c i t y 0.01728 m/day 0.59962 Gas Production Rate (mL/kg-day) 5.0 40.0 Refuse D e n s i t y 537.0 kg/m3 600.0 Landf i l l Depth 14.0 m 10.0 L a n d f i l l Area 80,000 m2 200,000 The source f o r the l e a c h a t e f l u x data was Atwater (1980), which g i v e s r e l i a b l e e s t i m a t i o n s of ammonia mass f l u x through the aqueous l e a c h a t e phase f o r both S t r i d e Ave. and Richmond Landf i l l s . To c a l c u l a t e the mass f l u x per l a n d f i l l per year, i t was 2 assumed the su r f a c e area at S t r i d e Ave. to be 80,000 m , while assuming the study s u r f a c e area of 200,000 m i n Richmond L a n d f i l l . To c a l c u l a t e an annual NH^-N emission f l u x , the NH^-N gas c o n c e n t r a t i o n values were averaged f o r each l a n d f i l l to get 195 an average y e a r l y NH^-N gas c o n c e n t r a t i o n . The average 3 c o n c e n t r a t i o n s found were 198.3 ug/m f o r S t r i d e Ave. and 92.8 3 ug/m f o r Richmond L a n d f i l l . These values were then inputed i n t o Thibodeaux's model to an average d a i l y f l u x of NH^-N gas. T h i s d a i l y f l u x was m u l t i p l i e d by the l a n d f i l l , s u r f a c e area and m u l t i p l i e d by 365 days to get the average annual f l u x of NH^-N gas. Flux values f o r both l a n d f i l l s are l i s t e d below i n Table 5.22. In these c a l c u l a t i o n s i t i s assumed that Richmond L a n d f i l l i s a s t a t i c system and gas e x t r a c t i o n through the w e l l system i s not t a k i n g p l a c e . 5.7.3.2. DISCUSSION OF RESULTS The r e s u l t s i n d i c a t e that i n both l a n d f i l l s , the annual NH^-N f l u x e s are very s m a l l . In r e a l i t y , t h i s value c o u l d be much l e s s i f the model would have accounted f o r a d s o r p t i o n and consumption of NH^-N through the l a n d f i l l cap. The r e s u l t s a l s o i n d i c a t e how much the f l u x i s due to. c o n v e c t i o n i n Richmond L a n d f i l l versus S t r i d e Ave. T h i s i s mainly due to S t r i d e Ave. gas flows being d i f f u s i o n dominated due to i t ' s low gas p r o d u c t i o n r a t e s and t h i c k l a n d f i l l cover. The t h i c k l a n d f i l l cover helps to slow down d i f f u s i o n because of a lengthened d i f f u s i o n path. 196 TABLE 5.22 - Comparing Annual NH.-N Gas Mass Fluxes For Both L a n d f i l l s . L a n d f i l l CONVECTION & D a i l y Flux (ug/m2-day) DIFFUSION Annual (kg/yr) DIFFUSION-D a i l y Flux (ug/m2-day) -ONLY Annual (kg/yr) S t r i d e Ave 19.9 0.582 18.3 0.536 Richmond 52.9 3.862 . 25.1 1 .832 Re s u l t s comparing f l u x e s from the documented e s t i m a t i o n s of NHg-N f l u x i n the leac h a t e are shown below i n Table 5.23. A l l r e s u l t s are repor t e d i n kg/yr. To c a l c u l a t e the p r o p o r t i o n of f l u x of NHg-N i n le a c h a t e from the Richmond study s i t e , i t was assumed that the 20 ha s i t e c o n t r i b u t e d to 1/5 of the t o t a l mass of ammonia leached. The t o t a l mass leached per year was 82,125 kg NH-j-N/yr (Atwater, 1 980), so the t o t a l mass f l u x from the study s i t e t o t a l e d 16,425 kg/yr. TABLE 5.23 - Comparison between Gas and Leachate Annual Fluxes of NHg-N, Both L a n d f i l l s . Gas Values (kg/yr) Leachate Value (Atwater, 1980) Percent of lea c h a t e mass f l u x Richmond S t r i d e Ave. 3.862 0.582 16,425 kg/yr 1 ,975 0.024 0.029 The r e s u l t s i n d i c a t e a very small f r a c t i o n of NH^-N being l o s t through the gas phase. Less than 3/100 th of 1 percent of the l e a c h a t e ammonia f l u x e s f o r both S t r i d e Ave. and Richmond 197 L a n d f i l l s . As mentioned before, these v a l u e s are probably the maximum f l u x o b t a i n a b l e , s i n c e the model does not account f o r any a d s o r p t i o n or consumption of ammonia before i t reaches the s u r f a c e of the l a n d f i l l . 5.7.3.3. COMPARISON OF MODEL RESULTS WITH GAS GENERATION MASS BALANCE RESULTS Since there are many l i m i t a t i o n s and assumptions to Thibodeaux's model, a comparison was made between the model r e s u l t s and a simple gas g e n e r a t i o n mass balance model. T h i s comparison was done to check the v a l i d i t y of the Thibodeaux model r e s u l t s . The gas g e n e r a t i o n mass balance model assumes that a covered l a n d f i l l produces a c e r t a i n f i n i t e mass of gas ( i e , CH^'CO^r etc . ) at a given r a t e throughout the l a n d f i l l e d r e f u s e . A l l t h i s gas produced i s then emitted through the l a n d f i l l cover. A gas g e n e r a t i o n r a t e can be i n f e r r e d from the l i t e r a t u r e , or be estimated from e x t r a c t i o n w e l l pumping r a t e s , which was p r e v i o u s l y d i s c u s s e d i n Chapter 2. The assumptions f o r the mass balance model are l i s t e d below f o r the Richmond L a n d f i l l case: 1. Assume gas e x t r a c t i o n i s r e c o v e r i n g a l l of the m i c r o b i o l o g i c a l l y generated gas. 2. Assume n e g l i g i b l e a i r i n t r u s i o n d u r i n g e x t r a c t i o n . 3. Assume the same average ammonia c o n c e n t r a t i o n (92.8 3 ug/m ) i n the generated gas as used i n Thibodeaux model c a l c u l a t i o n s . 4. Assume a l l generated gas i s m i g r a t i n g v e r t i c a l l y through 198 the l a n d f i l l cover, and that none of the gas i s being removed v i a the bottom of the l a n d f i l l or by the l e a c h a t e . 5. Assume a gas e x t r a c t i o n pumping r a t e of 725 CFM (20.5 3 m /min) f o r the study area at Richmond L a n d f i l l (E.H. Hanson & A s s o c i a t e s , 1988). . 6. Assume no b i o l o g i c a l sink of the generated gas before l e a v i n g the s u r f a c e of the l a n d f i l l . With these assumptions i n mind, the r e s u l t s f o r NH^-N mass emitted due s o l e l y to gas p r o d u c t i o n at Richmond L a n d f i l l i s l i s t e d i n Table 5.24. D e t a i l s of the c a l c u l a t i o n can be found i n Appendix B.16. In a d d i t i o n , a c a l c u l a t i o n i s i n c l u d e d to check the gas pr o d u c t i o n r a t e used i n the model run with the gas pro d u c t i o n r a t e c a l c u l a t e d f o r the mass balance model. T h i s mass balance p r o d u c t i o n r a t e was c a l c u l a t e d from the Richmond L a n d f i l l pumping 3 e x t r a c t i o n r a t e ( i e , 20.5 m /min). The f i n a l comparison i n d i c a t e s that the gas p r o d u c t i o n rate of 40 ml/kg-day used f o r Richmond L a n d f i l l was not i n e r r o r , s i n c e the pumping gas; production r a t e c a l c u l a t i o n i s at l e a s t 24.6 ml/kg-day when assuming 100% pumped recovery of any generated gas. Since pumping e x t r a c t i o n r a t e s were not a v a i l a b l e f o r S t r i d e Ave., a gas p r o d u c t i o n rate of the same 5 ml/kg-day f o r the model run was used i n the mass balance c a l c u l a t i o n . R e s u l t s of comparing the f l u x f o r the Thibodeaux model and mass balance models are l i s t e d below i n Table 5.24: 199 TABLE 5.24 - Comparison of Model Versus Mass Balance Flux C a l c u l a t i o n s . L a n d f i l l Model Flux (kg/yr) Mass Balance Flux D i f f e r e n c e (kg/yr) S t r i d e Ave. 0.582 0. 1 92 3 - f o l d Richmond 3.862 1 .000 3.8 - f o l d The r e s u l t s i n d i c a t e at l e a s t a 3 - f o l d d i f f e r e n c e e x i s t s between the model and mass balance c a l c u l a t i o n s . However, t h i s d i f f e r e n c e i s probably l e s s s i n c e the assumption of 100% e x t r a c t i o n of generated gas i s impossible to a c h i e v e . In f a c t , as s t a t e d i n Chapter 2, Pacey estimates that only 10 to 50 percent of the t h e o r e t i c a l gas produced w i l l be e x t r a c t e d (Boyle, 1976). I f t h i s i s the case, then the c a l c u l a t e d f l u x using the gas g e n e r a t i o n mass balance w i l l i n c r e a s e p r o p o r t i o n a l l y with a decrease i n gas e x t r a c t i o n e f f i c i e n c y . If t h i s i s t r u e , then the two model r e s u l t s may agree q u i t e f a v o r a b l y . 5.7.3.4. SUMMARY OF RESULTS The r e s u l t s of the f i r s t - o r d e r mass f l u x approximations i n d i c a t e that ammonia gas emissions are not a s i g n i f i c a n t p o r t i o n (<0.03%) of the ammonia f l u x e s apparent i n l a n d f i l l l e a c h a t e . T h e r e f o r e , these r e s u l t s i n d i c a t e that when e s t i m a t i n g an o v e r a l l ammonia or n i t r o g e n balance on these l a n d f i l l s , one can neg l e c t the ammonia l o s t through the gas emission phase. A l s o , the r e s u l t s i n d i c a t e that ammonia i s not a s u b s t a n t i a l c o n t r i b u t o r to l a n d f i l l gas contaminated a i r around covered l a n d f i l l s . 200 CHAPTER 6 6. CONCLUSIONS AND RECOMMENDATIONS The a n a l y t i c a l technique used f o r measuring ammonia from l a n d f i l l gas was the wet-chemical automated phenate technique. Samples were c o l l e c t e d i n the f i e l d by pumping u n f i l t e r e d l a n d f i l l gas through a b o r i c a c i d t r a p at a flow of around 6.0 L/min. Problems encountered with t h i s technique i n c l u d e sample contamination of p a r t i c u l a t e matter d u r i n g h a n d l i n g of samples, condensate b u i l d - u p i n sample t u b i n g , and negative i n t e r f e r e n c e s from the l a n d f i l l gas a f f e c t i n g both the accuracy of the sampling and a n a l y t i c a l method. Detection- l i m i t of the a n a l y t i c a l technique was found to be about 0.03 mg/L of NH^-N. T h i s value t r a n s l a t e s i n t o a d e t e c t i o n l i m i t of around 10 ug NH^/m3 of l a n d f i l l gas under normal sampling c o n d i t i o n s . The sampling technique was proven to be d e f i c i e n t i n approaching a q u a n t i t a t i v e recovery of NH3-N gas. Laboratory r e s u l t s suggest a recovery e f f i c i e n c y of about 50 % to be accurate i n a l a n d f i l l gas environment. T h i s recovery e f f i c i e n c y was expected due to a combination of high pumping flows and a l r e a d y low c o n c e n t r a t i o n s of NH^-N i n the l a n d f i l l gas. Since t h i s ammonia gas sampling and a n a l y s i s technique exceeded a l l the c r i t e r i a s t a t e d i n the study o b j e c t i v e s ( i e , f a s t , inexpensive, simple to use), t h i s author can conclude that t h i s technique i s a v a l i d method f o r d e t e c t i o n and measurement of ammonia i n l a n d f i l l gas. However, one should be c a u t i o u s when 201 i n t e r p r e t i n g the data analyzed from t h i s method s i n c e the accuracy may be hampered by the high humidity and s o l u b l e negative i n t e r f e r e n c e s apparent i n l a n d f i l l gas. The g r e a t e s t NH^-N i n leachate and gas was found i n Matsqui l a n d f i l l where gas valu e s of up to 650 ppb and leac h a t e values of over 2000 mg/L were d e t e c t e d . NHg-N gas c o n c e n t r a t i o n s were c o n s i s t e n t l y lowest i n Richmond L a n d f i l l while l e a c h a t e values ranged from 10 to 500 mg/L. Premier St. had f a i r l y c o n s i s t e n t leachate NH^-N and pH values of. around 200 mg/L and 6.60. While S t r i d e Avenue e x h i b i t e d the. lowest s t r e n g t h l e a c h a t e with NH^-N l e s s than 15 mg/L, i t always e x h i b i t e d higher than expected NH^-N gas v a l u e s . O v e r a l l , most NH^-N gas c o n c e n t r a t i o n s were l e s s than 150 ppb. Gas flow and methane f l u x was found to be g r e a t e s t i n the younger l a n d f i l l s with Richmond e x h i b i t i n g the g r e a t e s t f l u x e s and gas flows of over 20 kg/cm2-day i n some w e l l s (C6 and D9). The high flows and f l u x e s are mostly a r e s u l t of high gas pr o d u c t i o n r a t e s causing a b u i l d - u p of i n t e r n a l l a n d f i l l p ressure b u i l d - u p . A l s o , some flow may be due to thermal c o n v e c t i o n . 2 Most CH^ f l u x e s were found to be under 5.0 kg/cm -day, with , S t r i d e Ave. and Premier S t . e x h i b i t i n g f l u x e s u s u a l l y under 1.0 2 kg/cm -day. The v a r i a b l e found most o f t e n to cause a change i n NH^-N gas c o n c e n t r a t i o n was gas temperature (Tg). T h i s was d i s c o v e r e d not only i n the m u l t i p l e r e g r e s s i o n a n a l y s i s , but a l s o i n the Pearson c o r r e l a t i o n a n a l y s i s . The v a r i a b l e that may be causing 202 some of the observed c o o l i n g i n gas temperature i s i n f i l t r a t i n g p r e c i p i t a t i o n . T h i s i n f i l t r a t i n g p r e c i p i t a t i o n may a l s o cause the e f f e c t of de c r e a s i n g NH^-N gas c o n c e n t r a t i o n s i n the unsaturated zone from NH^ a b s o r p t i o n i n t o the lower pH (< 6.0) rainwater. Other parameters such as. CH^-flux, pH and NH^-N leac h a t e were found to e x p l a i n a minimal v a r i a t i o n i n ammonia gas c o n c e n t r a t i o n s . The r e s u l t s of the m u l t i p l e r e g r e s s i o n a n a l y s i s on CH^ % i n d i c a t e the g r e a t e s t r e l a t i o n s h i p o c c u r r e d between the dependent v a r i a b l e CH^, and i o n i c s t r e n g t h . The major l i m i t a t i o n s found with using r e g r e s s i o n a n a l y s i s as a p r e d i c t i v e t o o l , f o r NH^-N and CH 4 c o n c e n t r a t i o n s i s one, the non-normality present i n some of the data, two, the r e s u l t a n t low R2's and thr e e , the l a r g e r e s i d u a l e r r o r found i n the equations. In c o n c l u s i o n , p r e d i c t i o n of CH^ % and NH^-N gas by s t a t i s t i c a l methods i s very u n c e r t a i n due mainly to the h i g h l y v a r i a b l e and non-normal data c o l l e c t e d i n t h i s study. Decrease i n barometric pressure was d i s c o v e r e d not to incr e a s e s t a t i c gas flow r a t e s by a low pressure pumping e f f e c t observed i n other documented l a n d f i l l s . . In f a c t , some Matsqui w e l l s responded with lower flows d u r i n g lower atmospheric p r e s s u r e . One other o b s e r v a t i o n worth n o t i n g was the d e t e c t i o n of an abnormal N 2/0 2 l a n d f i l l gas r a t i o apparent i n a few Matsqui and S t r i d e Ave. sampling w e l l s . R a t i o s sometimes exceeded 20, which means oxygen i s being consumed by some proc e s s . T h i s process i s 203 p o s s i b l y a combination of i n o r g a n i c redox r e a c t i o n s and oxygen uptake from a e r o b i c b a c t e r i a c a l l e d Methanotrophs that consume CH^ and 0 2 to produce C0 2 gas. R e s u l t s of the the l a n d f i l l gas organic contaminant a n a l y s i s i n d i c a t e that over 50 compounds were dete c t e d i n Richmond and Matsqui w e l l s a f t e r the sampling technique was improved. Most of these compounds were s u b s t i t u t e d benzene and s a t u r a t e d hydrocarbons. A maximum of e i g h t c h l o r i n a t e d hydrocarbons were det e c t e d . Other compounds of i n t e r e s t that were de t e c t e d i n c l u d e some furans, b i p h e n y l s , phenol and naphthalene compounds. Re s u l t s of the comparison between documented Henry's.Law constants f o r p r e d i c t i n g NH^-N i n gas show some l a r g e d i s c r e p a n c i e s of over 2000 f o l d between the p r e d i c t e d and measured gas c o n c e n t r a t i o n s . A l l methods g r o s s l y u n d e r p r e d i c t the NH^-N i n the gas f r a c t i o n from S t r i d e Ave. while o v e r p r e d i c t i n g the gas c o n c e n t r a t i o n in w e l l s t h a t e x h i b i t NH^-N i n l eachate g e n e r a l l y g r e a t e r than 200 mg/L. The reasons for t h i s l a r g e d i s c r e p a n c y between p r e d i c t e d and measured r a t i o of NH^-N gas may not be j u s t due to i n v a l i d Henry's c o n s t a n t s . Other reasons are summarized below: 1. The a n a l y t i c a l technique i s not accurate., 2. The NH3-N leach a t e c o n c e n t r a t i o n i s not n e c e s s a r i l y r e f l e c t i v e of the NHg-N c o n c e n t r a t i o n inherent i n the unsaturated zone where the major f r a c t i o n of NH^-N mass t r a n s f e r to the gas phase may be o c c u r r i n g . Combined with t h i s are l a n d f i l l h e t e r o g e n i e t i e s and l a t e r a l gas m i g r a t i o n that p o s s i b l y make the 204 gas sample n o n - i n d i c a t i v e of the measured NH^-N c o n c e n t r a t i o n i n the l e a c h a t e . 3. The aqueous and gas phases of ammonia are not i n e q u i l i b r i u m i n a l a n d f i l l environment. 4. The NH^-N i s being volume d i l u t e d by high r a t e s of. gas pro d u c t i o n i n some w e l l s . 5. Discepancy i s due to l i m i t a t i o n s of NH^-N mass t r a n s f e r i n t o the gas phase. 6. Unpredicted s o l u b i l i t y changes of ammonia r e s u l t i n g from the l e a c h a t e chemistry. 7. Discrepancy c o u l d r e s u l t from a d s o r p t i o n and ^ s o l u b i l i z a t i o n of NH^-N i n the unsaturated zone. Probably a combination of p t s . 1 , 2 , 3 , 4 and 6 cause the m a j o r i t y of disc r e p a n c y between p r e d i c t e d and measured NH^-N gas. R e s u l t s comparing the NH^-N gas f l u x e s with NH^-N leachate f l u x e s show a n e g l i g i b l e f r a c t i o n of NH^-N mass being l o s t through the emission of l a n d f i l l gas. In a s i t u a t i o n c o n s i d e r e d to r e s u l t i n maximum emissions, the ammonia gas f r a c t i o n was found to be l e s s than 0.03 % of the ammonia leac h a t e mass f l u x i n both S t r i d e Ave. and Richmond L a n d f i l l s . Mass f l u x r e s u l t s . f o r NH3-N gas emission model a l s o agreed f a v o r a b l y with the r e s u l t s c a l c u l a t e d from a gas generation mass balance model. In summary, t h i s author b e l i e v e s there are some important i m p l i c a t i o n s that a r i s e from t h i s work on l a n d f i l l gas. One, i s the e f f e c t that c l i m a t e has on pro d u c t i o n of methane i n l a n d f i l l s . In c o l d e r , wetter c l i m a t e s such as Vancouver, 205 c o n t r o l l i n g the e f f e c t s of c l i m a t e would be paramount i n d e s i g n i n g a s u c c e s s f u l l a n d f i l l gas u t i l i z a t i o n p r o j e c t . Secondly, i s the issue of p r e d i c t i n g gas c o n c e n t r a t i o n s from . known leac h a t e values by usage of a documented Henry's Law c o n s t a n t . T h i s study's data imply that an a c c u r a t e p r e d i c t i o n using a documented Henry's constant may not be p o s s i b l e i n a l a n d f i l l . T h i s has f a r r e a c h i n g i m p l i c a t i o n s f o r persons t r y i n g to p r e d i c t gas c o n c e n t r a t i o n s of c e r t a i n v o l a t i l e hazardous wastes from given leachate v a l u e s . L a s t l y , the v a r i e d and d i s a p p o i n t i n g r e s u l t s of the s t a t i s t i c a l a n a l y s i s i n d i c a t e that e a s i l y measured l a n d f i l l parameters may not be u s e f u l i n p r e d i c t i n g the v a r i a t i o n i n c o n c e n t r a t i o n of gas components such as ammonia and methane. L i s t e d below are some p o t e n t i a l f u t u r e r e s e a r c h p r o j e c t s t h i s author f e e l s should be undertaken to b e t t e r improve t h i s study's work. 1. Set up a f i e l d apparatus i n an o b s e r v a t i o n w e l l that monitors the p o s s i b l e d i u r n a l t r e n d i n l a n d f i l l gas flow while monitoring changes in leachate pH and redox p o t e n t i a l and methane gas percent. The main advantage to t h i s system i s the r e a l time and continuous data o f f e r e d showing small temporal trends that can be simulated on a computer l a t e r . Other than the high c a p i t a l c o s t , a. disadvantage to t h i s system i s the p o t e n t i a l f o r vandalism. 2. In combination with the above, would be to set up instruments such as tensiometers and s u c t i o n l y s i m e t e r s to 2 0 6 monitor changes of moisture content and chemistry i n the unsaturated zone. T h i s would h e l p i n studying the e f f e c t s that p r e c i p i t a t i o n i n f i l t r a t i o n has on methane p r o d u c t i o n i n a f u l l -s c a l e l a n d f i l l . 3. To determine i f there i s an a c t i v e p o p u l a t i o n of methanotrophs in the l a n d f i l l environment an unsaturated zone sampling and s o i l e x t r a c t i o n study should be attempted to i s o l a t e t h e i r metabolic enzyme Methane Monooxygenase. 4. V a r i o u s p o t e n t i a l l a b o r a t o r y p r o j e c t s worth mentioning are l i s t e d below: - A study should focus on whether there i s a b i o f i l m c u l t u r e surrounding refuse or i s the b a c t e r i a p o p u l a t i o n mostly i n m i c r o c o l o n i e s . Determining t h i s would have great consequences on t r y i n g to model the mass t r a n s f e r of v o l a t i l e compounds l i k e ammonia. Study how the methanogens may be s t i m u l a t e d i n t o g r e a t e r gas p r o d u c t i o n r a t e s by an o p e r a t i n g gas e x t r a c t i o n system ( i e Richmond L a n d f i l l ) . The study would c o n s i s t of s u b j e c t i n g a sample of decomposing r e f u s e under anaerobic c o n d i t i o n s . while a p p l y i n g the usual vacuum s t r e s s e s a p p l i e d du r i n g gas e x t r a c t i o n . - Determine what value of Henry's constant i s a p p l i c a b l e i n a l a n d f i l l environment by using ammonia as the study compound. Th i s probably can be done in a c l o s e d anaerobic v o l a t i l i z a t i o n chamber. - Perform more d e t a i l e d r e s e a r c h i n t o the dynamics of 207 ammonia chemistry in l e a c h a t e . 5. To v e r i f y the modelled r e s u l t s of gaseous NH^-N mass f l u x , I would recommend q u a n t i f y i n g the emissions i n the f i e l d by the use of v o l a t i l i z i n g domes. T h i s technique i s d i s c u s s e d i n more d e t a i l by B a l f o u r et a l . (1987). To improve the accuracy of the model runs, there should be a study to estimate the f r a c t i o n of NH^-N mass adsorbed or consumed i n the l a n d f i l l cover. T e s t s should a l s o be performed on the l a n d f i l l to v e r i f y the valu e s chosen f o r standard parameters ( i e , p o r o s i t y , gas p r o d u c t i o n r a t e e t c . . . ) . L a s t l y , the model should be upgraded to simulate pressure pumping e f f e c t s while s o l v i n g f o r n- l a y e r e d and 2-d systems. T h i s would best be done by f i n i t e d i f f e r e n c e or f i n i t e element mod e l l i n g schemes. 208 CHAPTER 7 7. REFERENCES Alexander, M., I n t r o d u c t i o n to S o i l M i c r o b i o l o g y , John Wiley and Sons: New York, 1963. Al-Omar, M.A. et a l . , \"Impact of S a n i t a r y L a n d f i l l On A i r Q u a l i t y i n Baghdad,\" in Water, A i r , and S o i l P o l l u t i o n , 32 (1987) 55-61 . Ammonia, prepared by N a t i o n a l Research C o u n c i l , Subcommittee on Ammonia, U n i v e r s i t y Park Press, B a l t i m o r e , 1979 Atwater, J.W., F r a s e r River E s t u a r y Study Water Q u a l i t y , Impact of Landf i l l s , EPS, Environment Canada, 1980. B a c c i n i , P., et a l , \"Water and Element Balances of M u n i c i p a l S o l i d Waste L a n d f i l l s \" Waste Management & Research (1987), 5, 483-499. . Baker, L.W. and MacKay, K.P., \"Screening Models f o r E s t i m a t i n g Toxic A i r P o l l u t i o n Near a Hazardous Waste L a n d f i l l , \" i n the J . of the A i r P o l l u t i o n C o n t r o l A s s o c i a t i o n , V. 35, no. 11, Nov. 1985, pp.1190-1195. B a l f o u r , W.D. et al.,\"Sampling Approaches For the Measurement of V o l a t i l e Compounds at Hazardous Waste S i t e s , \" J o u r n a l of• :, •' Hazardous M a t e r i a l s , 14(1987)135-148. . B e l l , J.M., Development of a Method for Sampling and A n a l y z i n g Refuse, Purdue U n i v e r s i t y , Ph.D d i s s e r t a t i o n , 1963. Beluche, R.A. Degradation of S o l i d S ubstrates i n a S a n i t a r y L a n d f i l l , U n i v e r s i t y of Southern C a l i f o r n i a , Ph.D d i s s e r t a t i o n , 1968. B i r d and Hale, L t d . , 1978 M u n i c i p a l Refuse: S t a t i s t i c s f o r Canadian Communities of over 100,000 (1976-1977). A r e p o r t prepared f o r the Waste Management Branch, EPS. B o l l e t e r , W.T., et a l , \"Spectrophotometric Determination of Ammonia as Indophenol,\" i n A n a l . Chem., V o l . 33, No. 4, 1961. Bowerman, F.R., et a l . , A Case Study of the Palos Verdes L a n d f i l l . Gas Development P r o j e c t , E c o l o g i c a l Research S e r i e s , EPA -6003-047, J u l y , 1977. Boyle, W.C., \"Energy Recovery from S a n i t a r y L a n d f i l l s - a . Review,\" i n M i c r o b i a l Energy Conversion, ed. by S c h l e g e l , 209 H.G. and Barnea, J . , Proceedings from a seminar h e l d i n Gottingen, West Germany, Oct., 4-8, 1976, Pub. by E r i c h G o l t z e K.G., Gottingen, 1976. Brookes, B and Young, P.J. \"The Development of Sampling Methods and GC/MS A n a l y t i c a l Procedures to I d e n t i f y and Determine Minor Organic Components of L a n d f i l l Gas\" T a l a n t a , V o l . 30, No. 9, Sept. 1983, pp 665-676. Brosset, C , P o s s i b l e Changes i n A e r o s o l Composition Due to Departure from E q u i l i b r i u m C o n d i t i o n s During Sampling, The D i v i s i o n of Environmental Chemistry, ACS, Hawaii, A p r i l 1-6, 1979. Brown, W.H. I n t r o d u c t i o n to Organic Chemistry, 3rd E d i t i o n , W i l l a r d Grant Press:. Boston, Mass., 1982. Bruckman, P. and Muelder, W. \"Der G e r h a l t an Organischen Spurenstoffen i n Deponiegasen,\" S c h r i f t e n r e i h e d e r Landesontalt Immissionshutz Landes Nordrhein, Westfalm, Heft 55 (1982) . \" . ~ ~ ~ Carpenter, L.V. and S e t t e r , L.R., \"Some Notes on S a n i t a r y . , L a n d f i l l s , \" in American J . of P u b l i c H e a l t h , V o l . .30, A p r i l , 1940, pp. 385-393. Chain, E.S.K., and DeWalle, F. B .>; \"'Sanitary - L a n d f i l l Leachates and T h e i r Treatment,\" i n J o u r n a l of the Environmental E n g i n e e r i n g D i v i s i o n , ASCE, V o l . 102, No. EE2, A p r i l , 1976, pp 411-432. Chain, E.S.K., et a l . , \"Leachate Generation and C o n t r o l at L a n d f i l l D i s p o s a l S i t e s , \" from V o l 1 proceedings of New D i r e c t i o n s and Research i n Waste Treatment and R e s i d u a l s Mgt., June 22-28, 1985, U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B.C., 1985. Clement, B.N., Methane Production and M i g r a t i o n at Waste D i s p o s a l S i t e s , Waterloo U n i v e r s i t y , Masters T h e s i s , 1981. Crawford, J.F. and Smith, P.G., L a n d f i l l Technology, Butterworths Pub. Co.: Kent, England, 1983.. Dawson, G.A. \"Io n i c Composition of Rain During Six t e e n Convective Showers,\" i n Atmospheric Environment, V o l . 12, 1991-1998, 1978. E h r e n f e l d , J.R., et a l . , C o n t r o l l i n g V o l a t i l e Emissions at Hazardous Waste S i t e s , Pub. NOYES DATA Corp: Park Ridge, N.J., 1986. E l i a s s e n , R., \"Decomposition of L a n d f i l l s , \" i n American J . of 210 P u b l i c Health, V o l . 32, Sept., 1942, pp. 1029-1037. Emcon A s s o c i a t e s , Methane Generation and Recovery from L a n d f i l l s , P u b l i s h e d by Ann Arbor Science P u b l i s h e r s , Inc., 1980. E n g i n e e r i n g Science, Inc., E f f e c t s of Refuse Dumps on Groundwater Q u a l i t y , C a l i f . State Water P o l l u t i o n Contol Board, Pub. No. 24, Aug., 1961. I b i d . . . , I n - S i t u I n v e s t i g a t i o n of Movements of Gases Produced From Decomposing Refuse, C a l i f . S t ate Water P o l l u t i o n C o n t r o l Board, Pub. No. 31, 1965. I b i d . . . , F i n a l Report of I n - S i t u I n v e s t i g a t i o n of Movements of Gases Produced From Decomposing Refuse, C a l i f . State Water P o l l u t i o n C o n t r o l Board, Pub. No. 35, A p r i l , 1967. Farmer, et a l . , Land D i s p o s a l of Hexachlorobenzene Wastes - C o n t r o l l i n g Vapor Movement in S o i l , EPA - 600/2-80-119, 1980. Farquhar, G.J. and Rovers, F.A., \"Gas p r o d u c t i o n During Refuse Decomposition,\" i n Water, A i r and S o i l P o l l u t i o n , 4(1974)482-495. F i n d i k a k i s , A.N. and L e c k i e , J.0., \"Numerical S i m u l a t i o n of Gas Flow i n S a n i t a r y L a n d f i l l s , \" i n the J o u r n a l of the Environmental E n g i n e e r i n g D i v i s i o n , ASCE, V o l . 105, No. EE5, October, 1979, pp. 927-945. Freney, J.R. and Simpson, J.R., \"Ammonia V o l a t i l i z a t i o n , \" i n Ecology B u l l e t i n (Stockholm), ed. by C l a r k , F.E. and Rosswall, T., 33:291-302. Gandolla, M., et a l , \" P o s s i b i l i t i e s of Gas U t i l i z a t i o n with S p e c i a l Emphasis on Small S a n i t a r y Landf i l l s , \" E x p e r i e n t i a 38 (1982). Gardner, W.R. \"Movement of Nitrogen i n S o i l , \" i n S o i l N i t r o g e n , ed. by Bartholomew, W.V. and C l a r k , F.E., American S o c i e t y of Agronomy, 10, pp. 550-572. Geadah, M.L. N a t i o n a l Inventory of N a t u r a l and Anthropogenic Sources and Emissions of Ammonia (1980), Report EPS 5/IC/1, February, 1985. Gibs, J . , Schoenberger, R.J. and S u f f e t , I.H. \"A S i m p l i f i e d B u f f e r C a p a c i t y Model For S a n i t a r y L a n d f i l l Leachate,\" i n Water Research, V o l . 16, pp.699-705, 1982. G i u l i a n i , A. J . \" A p p l i c a t i o n of Conventional O i l and Gas D r i l l i n g Techniques to the Production of Gas from Garbage,\" 21 1 Proceedings, Transmission Conference, S a l t Lake C i t y , Utah, May 5-7, 1980, pub. by American Gas A s s o c i a t i o n . Golder A s s o c i a t e s , Report to Assoc. Eng. S e r v i c e s , LTD on Hy d r o q e o l o q i c a l I n v e s t i g a t i o n Premier S t r e e t L a n d f i l l , North Vancouver, B.C., September, .1983. Gossett , J.M., \"Measurement of Henry's Law Constants f o r C1 and C2 C h l o r i n a t e d Hydrocarbons,\" i n E n v i r o n . S c i . Technol., V o l . 21, No. 2, 1987. Grady, C.P.L. \"Modeling of B i o l o g i c a l F i x e d F i l m s - A State of the Art.Review,\" i n F i x e d F i l m B i o l o g i c a l Processes f o r Wastewater Treatment, P o l l u t i o n Technology Review, No. 104, ed. by Wu, Y.C. and Smith E.D., pub. by NOYES DATA Corp., 1 983. Grainger, J.M., Jones, K.L., Hotten, P.M. and Rees, J.F, \"E s t i m a t i o n and C o n t r o l of M i c r o b i a l A c t i v i t y i n L a n d f i l l s , \" i n M i c r o b i o l o g i c a l Methods For Enviromental Biotechnology, 1984, pp. 259-273.. Hales, J.M. and Drewes, D.R., \" S o l u b i l i t y of Ammonia i n Water at Low C o n c e n t r a t i o n s , \" i n Atmospheric Environment, V o l . 13, pp. 1133-1147, 1979. Halstead, E.C. Ground Water Supply - Fr a s e r Lowland, B r i t i s h Columbia, N a t i o n a l Hydrology Research I n s t i t u t e Paper No. 26, IWD S c i e n t i f i c S e r i e s No. 145, Saskatoon, Sasketchewan, .1 986. Ham, R.K., and ot h e r s , Recovery, P r o c e s s i n g and U t i l i z a t i o n of Gas from S a n i t a r y L a n d f i l l s , EPA - 600/2-79-001, 1979. Hanson, E.H. & Assoc., L t d . , Matsqui L a n d f i l l Gas System Operation and Maintenance, Report prepared f o r D i s t r i c t of Matsqui, J a n u a r y , 1 9 8 5 . Hanson, E.H. & Assoc., L t d . , Premier S t r e e t L a n d f i l l , L a n d f i l l Gas System Operations, Report prepared f o r . D i s t r i c t of North Vancouver, March, 1986. Hanson, E.H. & Assoc., L t d . , S t r i d e Avenue L a n d f i l l Gas M i g r a t i o n C o n t r o l , Report prepared f o r the D i s t r i c t of Burnaby, January, 1987. Hanson, E.H. & Assoc., L t d . , Richmond B.C. L a n d f i l l Gas P r o j e c t , an i n - o f f i c e r e p o r t , 1988. Hobson, P.N.., et a l . , \"Anaerobic D i g e s t i o n of Organic Matter,\" i n CRC C r i t i c a l Reviews i n Environmental C o n t r o l , CRC Press, Boca Raton, F l o r i d a , June, 1974, pp. 131-191. 212 Hughes, G.M., et a l . , Hydrogeology of S o l i d Waste D i s p o s a l S i t e s in Northeastern I l l i n o i s , I l l i n o i s State G e o l o g i c a l Survey, EPA Rpt. (SW - 1 2d), 1971. Jones, K.L., Rees, J.F. and Grainger, J.M., \"Methane Generation and M i c r o b i a l A c t i v i t y i n a Domestic Refuse L a n d f i l l , S i t e , \" i n the European J o u r n a l of A p p l i e d M i c r o b i o l o g y and Biotechnology, (1983) 18:242-245. ~ ~ ~ ~~~~ \" Junge, C.E., A i r Chemistry and R a d i o a c t i v i t y , Volume 4 of the I n t e r n a t i o n a l Geophysics S e r i e s , ed. by Mieghem, J.V., Academic Press: New York, 1963. Klee, A.J. and C a r r u t h , D. \"Sample Weights i n S o l i d Waste Management,\" i n J o u r n a l of S a n i t a r y E n g i n e e r i n g , ASCE, 96 (SA4) 945-954, Aug., 1970. Kotze, et a l . , \"Anaerobic D i g e s t i o n 11. The C h a r a c t e r i s t i c and C o n t r o l of Anaerobic D i g e s t i o n , \" Water Research, V o l . 3 (1969). Kro s t , K.J., et a l . , \" A n a l y s i s of Hazardous Organic Emissions,\" in A n a l . Chem., 1982, 54, 810-817. Large, P.J., \"Methylotrophy and Methanogenesis,\" in V o l . 8 of Aspects of M i c r o b i o l o g y , ed. by Cole, J.A., et a l . , 1982. Leak, D.J. and Dalton, H., \"Growth Y i e l d s of Methanotrophs,\" i n A p p l i e d M i c r o b i o l o g y and Biotechnology, (1986) 23: 477-481 . L e c k i e , J.O., Pacey J.G. and Halvadakis, C., \" L a n d f i l l Management With M o i s t u r e . C o n t r o l , \" i n J o u r n a l of Environmental E n g i n e e r i n g , ASCE, V o l . 105, No. EE2, A p r i l , 1979, pp. 337-355. Lu, J.C.S., et a l , Leachate From M u n i c i p a l L a n d f i l l s Production and Management, P o l l u t i o n Technology Review No. 119, Noyes p u b l i c a t i o n , C a l s c i e n c e Research, Inc., Huntington Beach, C a l i f . , 1985. MacKay, D. and Shiu, W.Y. \"Henry's Law Constants\" i n J o u r n a l of P h y s i c a l and Chemical Reference Data, 10(4), 1175-1199, ,1981 . McBean, E.A. and Farquahar, G.J., \"An Examination of Temporal/Spatial V a r i a t i o n s In L a n d f i l l - G e n e r a t e d Methane Gas,\" i n Water, A i r , and S o i l P o l l u t i o n , 13(1980)157-1 Merz, R.C., \" I n v e s t i g a t i o n of Leaching of a S a n i t a r y L a n d f i l l , \" C a l i f o r n i a State Water P o l l u t i o n C o n t r o l Board, 213 P u b l i c a t i o n #10, Sacramento, CA., 1954. Metry, A. and Cross, F.L. J r . , Leachate C o n t r o l and Treatment, V o l . 7 of the Environmental Monograph S e r i e s , a Technomic P u b l i c a t i o n , Westport, Conn., 1978. Mohsen, M.F.N., Farquahar, G.J. and Kouwen, N., \"Gas . M i g r a t i o n and Vent Design at L a n d f i l l S i t e s , \" i n Water, A i r and S o i l P o l l u t i o n ,•'1 3 (1 980)79-97 . M i l l i n g t o n , R.J., and Quirk, J.M., \" P e r m e a b i l i t y of Porous S o l i d s , \" Trans. Faraday Soc., 57:1200-1207 (1961). Nagase M. and Matsuo T., \" I n t e r a c t i o n s Between Amino-Acid-Degrading B a c t e r i a and Methanogenic B a c t e r i a i n Anaerobic D i g e s t i o n , \" i n Biotechnology and B i o e n g i n e e r i n g , V o l . XXIV, pp. 2227-2239 ( 1 982) . - - . • Ngo, T.T., et a l , \" I n t e r f e r e n c e i n Determination of Ammonia with the H y p o c h l o r i t e - A l k a l i n e Phenol Method of B e r t h e l o t , \" i n An a l . Chem., V o l . 54, No. 1, January, 1982. O k i t a , T. and Kanamori, S., \"Determination of Trace C o n c e n t r a t i o n of Ammonia in the Atmosphere Using P y r i d i n e - P y r a z o l o n e Reagent,\" in Atmospheric Environment, 1971, V o l . 5, pp 621-627. . Onuma, M. and Omura, T., \"Mass-Transfer C h a r a c t e r i s t i c s Within M i c r o b i a l Systems,\" in Water S c i . Tech., V o l . 14, Capetown, pp 553-568, 1982. Par ton., W.J.-, et a l . \" N H 3 - V o l a t i l i z a t i o n Model,\" i n Simulation, of Mitroqen Behavior i n S o i l - P l a n t Systems, ed. by F r i s s e l , M.J. and van Veen J.A., Centre f o r A g r i c u l t u r a l P u b l i s h i n g and Documentation, Wageningen, 198-1 Peddie, C.C. RBC Treatment of a M u n i c i p a l L a n d f i l l Leachate: A P i l o t Scale E v a l u a t i o n , U n i v e r s i t y of B r i t i s h Columbia, Masters T h e s i s , Oct., 1986. Perry, J.H., Chemical Engineers Handbook, 4th ed., M c G r a y - H i l l : New York, 1963. P f e f f e r , J.T., \"Temperature E f f e c t s on Anaerobic Fermentation of Domestic Refuse,\" i n Biotechnology and B i o e n g i n e e r i n q , V o l . XVI, pp 7.71-787, 1974. : Qasim S.R. and B u r c h i n a l , J.C., \"Leaching From Simulated l a n d f i l l s , \" in J o u r n a l WPCF, Vo l 42, No. 3 , P a r t 1, pp. 371-379, March, 1970. Ramasaway, F.L., A n a l y s i s of A c i d and Gas From Simulated 214 Landf i l l , U n i v e r s i t y of West V i r g i n i a , Ph.D. D i s s e r t a t i o n , 1969. Rathbun, R.E. and T a i , D.Y., \" V o l a t i l z a t i o n of Ketones From Water,\" i n Water, A i r and S o i l P o l l u t i o n , 17 (1982) 281-293. Raveh A. and Avnimelch Y., \"Leaching of P o l l u t a n t s From S a n i t a r y L a n d f i l l Models,\" i n J o u r n a l WPCF, V o l . 51, No. 11, Nov. 1979, pp. 2705-2716. Reddy & P a t r i c k , \" A e r a t i o n E f f e c t s on S o i l , \" i n Chemistry M o b i l i t y and R e a c t i v i t y i n S o i l Systems, SSSA S p e c i a l P u b l i c a t i o n No. 11, 1983. Rees, J.F., \"The Fate of Carbon Compounds in the L a n d f i l l D i s p o s a l of Organic Matter,\" i n J o u r n a l of Chemical Technology and Biotechnology, 1980, 30, 161-175. Robinson, H.D. and Lucas, J.L., '\"The Behavior and A t t e n u a t i o n of Leachate from Domestic Waste in a L a n d f i l l with a Designed and Engineered Unsaturated Zone. Instrumentation and Research at Stangate East L a n d f i l l , i n Kent, England,\" i n V o l . 1, Proceedings of New D i r e c t i o n s and Research i n Waste Treatment and R e s i d u a l s Mgt., June 23-28, 1985, U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B.C., .1985. Rovers, F.A. and Farquahar, G . J . , \" I n f i l t r a t i o n and L a n d f i l l Behavior,\" i n J o u r n a l of the Environmental E n g i n e e r i n g D i v i s i o n , ASCE, EE5, October, 1983, pp. 671-690. Saxena, P., et .'al, '.\"A-Comparative Study of E q u i l i b r i u m Approaches to the Chemical C h a r a c t e r i z a t i o n of Secondary A e r o s o l s , \" i n Atmospheric Environment, V o l . 20, No. 7, pp 1471-1483, 1986. Scheiner, D., \"Determination of Ammonia and K j e l d a h l N itrogen by Indophenol Method,\" i n Water Research, V o l . 10, pp 31-36, Pergamon Press, 1976. Schumacher, M.M., L a n d f i l l Methane Recovery, P u b l i s h e d by Noyes Data C o r p o r a t i o n , Park Ridge, New J e r s e y . Shen, T.T. , \" C o n t r o l Techniques f o r Gas Emissions From Hazardous Waste L a n d f i l l s , \" i n J o u r n a l of the A i r P o l l u t i o n C o n t r o l Assoc., V o l . 31, No. 2, February, 1981 . Shen, T.T., \" A i r Q u a l i t y Assessment f o r Land D i s p o s a l of I n d u s t r i a l Wastes,\" i n Environmental Management, V o l . 6, No., 4, pp 297-305, 1982. Shendrikar, A.D. and Lodge, J.P., \"Microdetermination of Ammonia by the Ring Oven Technique and i t s A p p l i c a t i o n to A i r P o l l u t i o n S t u d i e s , \" i n Atmospheric Environment, V o l . 9, pp 215 431-435, 1975. Skarheim, H.P., \"Tables of the F r a c t i o n of Ammonia i n the Undissociated.Form f o r PH 6 to 9, Temperature 0-30 C, TDS 0-3000 mg/1, and s a l i n i t y 5-35 g/kg,\" SERL Report, No. 73-5, pp 33, S a n i t a r y E n g i n e e r i n g Research Laboratory, U n i v e r s i t y of C a l i f o r n i a , B e rkeley. . Smith, O.L., S o i l M i c r o b i o l o g y : A Model of Decomposition and N u t r i e n t C y c l i n g , CRC S e r i e s i n Mathematical Models i n M i c r o b i o l o g y , CRC Press, Inc., Boca Raton, F l o r i d a , 1982. Snoeyink, V.C., and J e n k i n s , 0., Water Chemistry, John Wily & Sons: New York, 1980. Songonuga, O.O.0., A c i d Gas & M i c r o b i a l Dynamics of S a n i t a r y Landf i l l s , U n i v e r s i t y of West V i r g i n i a , Ph.D. D i s s e r t a t i o n , 1 970. Standard Methods for the Examination of Water and Wastewater, S i x t e e n t h E d i t i o n , p u b l i s h e d by APHA, Wash. D.C., 1985. Stegmann, R. and S p e n d l i n , H.H. \"Research A c t i v i t i e s on Enhancement of Biochemical Processes i n S a n i t a r y L a n d f i l l s , \" in V o l . 1 of Proceedings of New D i r e c t i o n s and Research i n Waste Treatment and D e s i d u a l Mgt., June 23-28, 1985, U n i v e r s i t y of B r i t i s h Columbia(Vancouver, B.C., 1985. Stephens, R.D., B a l l , N.B. and Mar, D.M. \"A Multimedia Study of Hazardous Waste L a n d f i l l Gas M i g r a t i o n , \" i n P o l l u t a n t s i n a Multimedia Environment, ed. by Cohen, Y., Plenum P r e s s : New York, Jan., 1986. Stewart, B.M., \" E f f e c t of Temperature on the Formation of Indophenol Blue i n A S p e c t r o p h o t o m e t r y Method f o r Determination of Ammonia,\" Water Resources, V o l 19(11) 1443-1445, 1985. Stumm, W. and Morgan, J . J . , Aquatic Chemistry, a • Wiley--I n t e r s c i e n c e P u b l i c a t i o n , 1981. SPSS:X Users Guide, by Spss, Inc., pub. by McGraw-Hill, New York, New York, 1983 The Sources, Chemistry, Fate and E f f e c t s of Ammonia i n Aquatic Environments, Prepared f o r American Petroleum I n s t i t u t e , . by E c o l o g i c a l A n a l y s t s , Inc., Sparks, Maryland,. 1981. , T a n a s c i , B.S., \" S a n i t a r y L a n d f i l l - Leachates and Gas C o n t r o l , \" i n Wastes Management, Oct., 1982. Tchobanoglous, G., Thiesem, H. and E l i a s s e n , R. S o l i d Wastes, 216 E n g i n e e r i n g P r i n c i p l e s and Management Issues, McGraw-Hill Book Company: New York, 1977. Tchobanoglous, G. and Schroeder, E.D., Water Q u a l i t y , Addison-Wesley P u b l i s h i n g Co.:Reading, Mass., 1985. Thibodeaux, L . J . , Chemodynamics, a W i l e y - I n t e r s c i e n c e P u b l i c a t i o n , 1979. Thibodeaux, L . J . , \" E s t i m a t i n g the A i r Emissions of Chemicals From Hazardous Waste L a n d f i l l s , \" i n J o u r n a l of Hazardous M a t e r i a l s , 4(1981) 235-244, 1980. Thibodeaux, L . J . , \"Models of Mechanisms for the Vapor Phase Emission of Hazardous Chemicals From L a n d f i l l s , \" i n J o u r n a l of Hazardous M a t e r i a l s , 7(1982)62-74. Thompson, F.C., M i c r o b i o l o g y and F a t t y A c i d P r o d u c t i o n i n S a n i t a r y L a n d f i l l s , West V i r g i n i a U n i v e r s i t y , Masters T h e s i s , 1969. Thurston, R.V., et a l , Aqueous Ammonia E q u i l b r i u m C a l c u l a t i o n s , T e c h n i c a l Report No. 74-1, F i s h e r i e s Bioassay Laboratory, Montana State U n i v e r s i t y , J u l y , 1974. T o e r i e n , D.F. and H a t t i n g h , W.H.J., \"Anaerobic D i g e s t i o n I. The M i c r o b i o l o g y of Anaerobic D i g e s t i o n , \" Water Resources, 3(1969) 385-416. Vogel, T.M., C r i d d l e , C.S. and McCarty, P.L., \"Transformation of Halogenated A l i p h a t i c Compounds,\" E n v i r o n . S c i . Technol. 21(8)722-736, 1987. Waksman, S.A., et a l , S o i l Microbes and T h e i r I d e n t i f i c a t i o n , 1931 . W h i t f i e l d , M., \"The H y d r o l y s i s of Ammonium Ions i n Sea Water - A T h e o r e t i c a l Study,\" in Marine B i o l . Ass. U.K., (1974) 54,565-580. Winter, K., \" K r i t e r i e n b ei b a u l i c h e n E i n r i c h t u n g e n au'f Deponien h i n s i c h t l i c h der Gefahrdung durch Gase,\" i n Forschungsbericht Nr. 103 02 102, E r i c h Schmidt V e r l a g , B e r l i n , 1979. Wolfe, R.'S. and Higgins, I . J . , \" M i c r o b i a l Biochemistry of Methane - A Study in C o n t r a s t s , \" i n M i c r o b i a l b i o c h e m i s t r y , V o l . 21, ed. by Quayle, J.R., 1979. Young, P. and Parker, A., \"Vapors, Odors and Toxic Gases from L a n d f i l l s , \" in Hazardous and I n d u s t r i a l Waste Management and T e s t i n g : T h i r d Symposium, ASTM STP 851, ed. by Jackson LP. 217 et a l . , P h i l a d e l p h i a , 1984, pp 24-41. Zehnder, A.J.B., \"Ecology of Methane Formation,\" i n Water P o l l u t i o n M i c r o b i o l o g y , V o l . 2, ed. by M i t c h e l l , R., 1978. 218 SAMPLE CH4 X C02 X N2 X 02 X 1 94 . 1 3 . 1 2 . 1 0 7 2 94 . 5 3 . 1 1 . .8 0. 6 3 94 . 3 3 . 1 2 .0 0. .6 4 93 .6 3 .0 2 .6 0. a 5 93 . 4 3 .0 2 .5 1 . 1 6 92. . 3 3. .0 3. .4 1 . 3 7 92. .0 2 . 8 4 0 1 . 2 8 91 . . 4 3. .0 4. . 1 1 . 5 9 90. .6 2. 9 4. 8 1 . 7 10 89 . . 4 2 . 9 5. 6 2 . 0 MEAN = 9 2 . 6 STD. DEV. = 1.61 APPENDIX A . I . - R e s u l t s o f Gas P a r t i t i o n e r T e s t i n g TIME t h o u r s ) 0 2. 25 4.5 6. 75 9 21.5 28.5 VIAL 1 71.2 19.6 88.04 6 75.4 16.4 7 6 . 1 15.8 73.7 17.4 68.6 21.6 64.9 24.7 V I A L 2 72.9 18.4 76.7 15.4 6 0 . 1 28.8 76 . 3 15.4 67 22.9 63.2 2 6 . 1 60.4 .28.3 V I A L 3 54.2 33. 7 82.7 10.2 7 7 . 1 14.8 75.7 16.2 72 18.8 67.5 2 2 . 5 64.6 24.8 VIAL 4 7 8 . 1 14.2 83.6 10 8 2 . 3 10.6 7 3 . 1 18. 1 7 0 . 7 20 68.6 21.6 63.8 25.4 V I A L 5 87 . 7 9.3 85 8.5 81.8 1 1 63.5 2 6 . 3 66.4 23.4 60.5 2 8 . 1 54.6 32.9 VIAL 6 81.2 11.8 84 . 4 9.2 6 8 . 3 2 2 . 1 79.5 12.9 75 16.6 64.2 25.2 57 :6 30.5 A p p e n d i x A2 - R e s u l t s o f L e a k a g e T e s t s on Gas S a m p l e V i a l s 219 APPENDIX A.3.- Recovery e f f i c i e n c y data f o r 6-0 L/min RUN BUBBLER NO. ESCAPE RECOVERY 1 2 3 1 82.1 47.6 26.2 18.3 47.1 2 98.2 22.0 22.0 15.4 62.3 3 102.8 22.0 21.7 15.2 63.6 4 144.8 21.8 21.8 15.3 71.0 MEAN 107.0 28.4 22.9 16.0 61.4 STD. DEV. 26.7 6.5 2.2 1.4 10.0 % C.V. 25.0 23.0 9.5 9.5 16.3 APPENDIX A. 4.- Recovery E f f i c i e n c y data f o r 2.1 L/min 1 92.9 38.1 37.5 26.3 47.7 2 183.9 38.0 82.8 58.0 50.7 3 144.0 32.0 54.0 37.8 53.8 MEAN 140.3 36.0 58.1 40.7 51.0 STD. DEV. 45.6 3.5 38.3 16.0 3.1 % C.V. 32.5 9.7 65.9 39.4 6.0 APPENDIX A. 5.- Recovery e f f i c i e n c y data f o r 10. 5 L/min 1 86.5 30.1 30.4 21.3 41.4 2 91.1 40.5 21.5 15.1 54.2 3 91.8 44.9 20.6 14.4 53.5 MEAN 89.8 38.5 24.2 16.9 53.0 STD. DEV. 2.9 7.6 5.4 3.8 1.5 % C.V. 3.2 19.7 22.4 22.4 2.8 220 APPENDIX A.6. - RESULTS OF pH METER COMPARISON In an attempt to c a l c u l a t e the accuracy of the Horizon f i e l d pH meter a comparison was made between t h i s and the l a b reference Beckman 44 pH meter. The Beckman 44 has an L C D - d i g i t a l d i s p l a y readout and i s equipped with a calomel combined r e f i l l a b l e e l e c t r o d e . Comparison of the two meters was made with v a r i o u s pH b u f f e r s o l u t i o n s and d i s t i l l e d water. Results of the comparison are shown below: Sample Beckman Horizon % E r r o r D i s t l . water D i s t l . water + 0.2 ml a l i q u o t of 6N NaOH 5.39 1 1 .54 A l i q u o t of 9.17 disodium t e t r a b o r a t e Na 2B 40 ?'10H 20 A l i q u o t of KH 2P0 4 4.67 KH oP0. + Na.B.O,.10H-0 6.16 2 4 2 4 7 2 Above mixture + 6.30 a l i q u o t of 0.02N NaOH Bo r i c a c i d (20,000 ppm) 4.59 D i s t l . water 5.63 pH 7 b u f f e r 6.99 pH 4 b u f f e r 4.00 5.28 10.34 8.94 4.43 6.30 6.43 3.49 5.0-2 6.76 3.89 -2.0 •10.4 -2.5 -5. 1 + 2.3 + 2.0 -24.0 •10.8 -3.3 -2.8 Inspection of these r e s u l t s show the g r e a t e s t e r r o r to occur l a t e in the comparison with the b o r i c a c i d . In g e n e r a l however, the r e l a t i v e e r r o r of the Horizon pH meter i s l e s s than + 5 % in the leachate pH range encountered i n t h i s study and u s u a l l y underpredicts the pH. E r r o r s are probably due to the Orion e l e c t r o d e not having enough time to e q u i l i b r a t e with the c o n t a c t i n g i o n i c s o l u t i o n . To guard a g a i n s t e l e c t r o d e s e n s i t i v i t y decay, the Orion e l e c t r o d e was \"rejuvenated\" in s a t u r a t e d KCl s o l u t i o n almost every two weeks. 221 APPENDIX A.7. - SUMMARY TABLE OF QUALITY ASSURANCE TESTS METHOD ACCURACY RESULTS Horizon F i e l d pH meter (Compared to Beckman 44 Lab pH meter) Ammonia D i s t i l l a t i o n -T i t r a t i o n Method F i s h e r Gas P a r t i t i o n e r Methane gas sample v i a l s % E r r o r of +2.3 to -24.0 % Us u a l l y l e s s than + 5 % of one pH u n i t ( D e t a i l e d i n Appendix A.6.) 20 mg/L NH3-N sample 4.2 % 200 mg/L sample 2.2 % (6 Samples each) % E r r o r of + 1.74 % (10 sample i n j e c t i o n s ) ( D e t a i l e d i n Appendix A.1.) % Leakage was 21.3 to 35.8 % over a 28 hr. p e r i o d . Mean leakage value was 26.8 % (D e t a i l e d i n Appendix A.2.) Note: Accuracy t e s t s of the NH3-N gas a n a l y t i c a l method are dis c u s s e d i n Chapter 5. 221 APPENDIX B. - SAMPLE CALCULATIONS OF SOME OF THE PARAMETERS B. 1 . CALCULATION OF CH4 FLUX THROUGH SAMPLE WELLS Known parameters a r e : - CH4 % by volume - Molecular weight of CH4 = 16.0 gm/mole - S t a t i c gas flow i n L/min - C r o s s - s e c t i o n a l area through measurement tube r = 1.27 cm. A = 5.07 cm Gas temp, i n K - Gas constant, R = 0.082057 L-atm/K-mol - Assume gas i s behaving i d e a l l y i d e a l gas law pV .= nRT - Where V = Flow * Time - So Q (Flow) = V/t Assume p = 1 atm. - So p/R = 12.195 K-mol/L 2 - To get CH. Flux i n kg CH./cm -day then m u l t i p l y by proper conv e r s i o n f a c t o r s to get from volume percent i n t o mass. The r e f o r e , CH4 Flux i s : CH 4 Flux = 55.6 * (Q/T°K) * (CH 4 %/l00) Example C a l c u l a t i o n i s : Suppose I have a w e l l flow of 20 L/min., Gas Temp, of 290°K, CH 4 of 50 %, then w i l l get: CH 4 Flux = 55.6 * (0.1034) * (0.50) = 2.8800 kg CH 4/cm 2-day B.2. CALCULATION OF C02 FLUX Is the same procedure as f o r CH. Flux except the molecular weight i s i n c r e a s e d to 44.0 gm/mole to change the equation below: C0 2 Flux i n kg C0 2/cm2-day = 152.52 * (Q/T°K) * (C0 2 %/l00) B.3. CALCULATION OF LANDFILL GAS DENSITY Summation of the four main l a n d f i l l gas c o n s t i t u e n t s , CH., C0 2, N 2, 0 2 were assumed to be i n d i c a t i v e of the t o t a l l a n d f i l l gas c o n c e n t r a t i o n . D e n s i t y f o r each gas taken from the l i t e r a t u r e ( l i s t e d below) was summed in the spreadsheet to get t o t a l gas d e n s i t y f o r each w e l l i n each sample p e r i o d . 222 GAS DENSITY SOURCE CH 4 0 .714 kg/m5 Emcon Assoc. (1980) c o 2 1 .950 kg/m3 Emcon Assoc. (1980) N 1 .248 kg/m3 CRC Handbook of Chem. and P h y s i c s (1979) °2 1 .427 kg/m\"3 Same as above T o t a l gas d e n s i t y was c a l c u l a t e d as f o l l o w s : Gas d e n s i t y = ((CH %/l00)*0.714) + ((C0 9%/100)*1.950) + ...... + ( ( N 2 V 1 0 0 ) * 1 .248) •+ ( (0 2 %7100)*1 .427) B.4. CALCULATION OF PPB IN GAS Pa r t s per b i l l i o n of NH--N gas was c a l c u l a t e d by d i v i d i n g to NH--N gas c o n c e n t r a t i o n i n t o the t o t a l gas d e n s i t y to get . comparable mass u n i t s : ug/kg = uq/nJ- NH3-N = ppb kg/m Densit y ' 3 3 Sample C a l c u l a t i o n of NH3-N of 200 ug/m . and d e n s i t y =1.30 kg/m 200 ug/m- = 153.8 ppb 1.30 kg/m3 . . B.5. CALCULATION OF IONIC STRENGTH From Snoeynk and Jenkins (1980) i s a con v e r s i o n f a c t o r f o r c o v e r t i n g s p e c i f i c conductance, i n t o i o n i c s t r e n g t h : • -5 Spec. Conduct.* 1.6 x 10 = Ionic. Strength B.6. CALCULATING ACTIVITY COEFFICIENTS The Debye-Huckle approximation was used and the equation below i s v a l i d where i o n i c s t r e n g t h do not exceed 0.1, which i s a p p r o p r i a t e f o r my r e s u l t s s i n c e only two w e l l s , F1 and F5 Matsqui exceeded the 0.1 I. 2 0 5 lo g 0 5 1 + Ba*I u* Where A = 0.50 z = 1.0 f o r NH. + + B =. 0.326E+08 . a = 3.0E-08 f of NH^ ions 223 Sample c a l c u l a t i o n : suppose l e a c h a t e of 2000 umho/cm then the a c t i v i t y c o e f f i c i e n t i s : log = - (0,50*1.0*0.032 0' 5)/ 1 + (0.978*0.032°* 5) = a n t i l o g (-0.076) =0.84 B.7. CALCULATE FRACTION OF UNIONIZED AQUEOUS AMMONIA Thurston et a l (1974) regressed the data obtained from P i n c h i n g and Bates i n t o workable equations e s t i m a t i n g pKa and f r a c t i o n of ammonia below: pKa = 0.0901821 + 2729.92/T°K T h i s equation i s found to have about a 5 % C.V., which i s exceptable. The f r a c t i o n i s then c a l c u l a t e d below: f = 1 / ( 10 p K a \" p H + 1) This f r a c t i o n can then be m u l t i p l i e d by the t o t a l ammonia measured to get the c o n c e n t r a t i o n , m o l a r i t y and mole f r a c t i o n f*C(NH 3-N) = C(NH 3) C(NH 3)/17.04 g/mole = [NH 3|aq]/55.6 m/L = X(NH 3) B.8. ESTIMATION OF pKw The i o n i z a t i o n constant of water i s a f u n c t i o n of temperature from the below e q u i l i b r i u m e x p r e s s i o n : Kw = [H +]*[OH~] The data used to p r e d i c t , the pKw as a f u n c t i o n of temperature was taken from Freney (1981): Temp, i n c e l s i u s pKw 0 14.944 5 14.734 10 14.535 15 14.346 20 14.167 25 13.997 30 13.833 35 13.680 40 13.535 The r e s u l t a n t r e g r e s s i o n equation i s : 224 pKw = 24.50198 - 0.03517(T°K) r 2 = 0.996584 - standard e r r o r i s 2.2 % i n t h i s equation B.9 CALCULATION OF AQUEOUS AMMONIA FROM EQUUILIBRIUM EXPRESSION Th i s method i s an a l t e r n a t i v e to Thurston's c a l c u l a t i o n . I t i s based on the e q u i l i b r i u m e x p r e s s i o n of ammonia and water below: NH3.+ H 20 <====> NH 4 + + OH~ K 1 = ( [ N H 4 + ] * *[OH~J)/[NH 3|aq] Kw = [H +]*[OH~] Where pK^ = pKw .- pKa Where [OH ] i s estimated from antilog(-(pKw-pH) So [NH 3|aq] = [NH 4+]* *[OH-] Example i s a le a c h a t e of 200 mg/L t o t a l ammonia a of 0.80, a pH of 6.5 and a leac h a t e T of 15 degrees. [ N H 4 + ] = 0.200 g/L/17.04 gm/mole = 0.012 m/L pKa = 9.569 pKw = 14.373 pK- = 4.80 or R ] = 1.58E-08 [OH~] = a n t i l o g ( - 7 . 8 7 ) = 1.34E-08 m/L [NH 3|aq] =8.11E-06 m/L B.10 ESTIMATION OF HENRY'S CONSTANT (Hi) FROM THE VAPOR PRESSURE METHOD a. Must f i r s t c a l c u l a t e the re f e r e n c e vapor pressure as a f u n c t i o n of temperature (from NRC, 1979): l o g P r e f =9.95028 - 0.003863(T) - 1473.12/T Where T = K P r e f = m m H 9 ; V To get i n t o atmospheres m u l t i p l y mm Hg by 0.0013 b. C a l c u l a t e s o l u b i l i t y as a f u n c t i o n of temperature from Freney (1981) data to get r e g r e s s i o n equation below: 225 l o g S = 1.307360 + 934.63/T where T = K r 2 =0.999806 Standard e r r o r i s only 0.04 % c. Must c a l c u l a t e c o r r e c t e d vapor pressure (P_) s i n c e a d i l u t e s o l u t i o n doesn't obey Raoult's Law of an i d e a l s o l u t i o n , so a c o r r e c t e d vapor pressure as a f u n c t i o n of i t ' s s o l u b i l i t y i s employed (MacKay and Shiu, 1981). P = P , * (1 - w) c ref Where w i s the f r a c t i o n of s o l u b i l i t y of the weight of ammonia in a given weight of water. T h e r e f o r e : H 1 i n atm-L/mole = Pc/S d. Example c a l c u l a t i o n f o r s o l u t i o n at 25 degrees c e l s i u s H = (9.32 atm * (1 - (26.92/55.6)))/26.92 m/L H J = 0.1786 atm-L/mole B.11 ESTIMATION OF H2 FROM THE MOLE FRACTION METHOD Two complete sources of data were used to estimate H2 as a f u n c t i o n of temperature. The sources are l i s t e d below: Temp Tchobanaoglous Perry Thibodeaux (1985) (1963) (1979) 0 0.48 0.38 — 10 0.78 0.62 20 1.25 : 0.99 25 1.56 1.24 0.84 30 1.96 1 .57 • 40 2.94 1.96 50 2.70 — At 25 degrees, a s t a t i s t i c a l comparison of the three sources y i e l d s a h i g h l y v a r i a b l e mean of 1.104 with a standard d e v i a t i o n of 0.396 and a % C.V. of 36 %. When averaging the two complete s e t s of data one gets the r e g r e s s i o n equation below: H 2 = -7.83 + 0.03(T) where T = K 226 r 2 = 0.996236 Standard E r r o r i s over 3 % Example c a l c u l a t i o n at 25 degrees: H 2 = 1.104 atm/X H 2 = 0.902 X/atm .;. 0.906X*55.6 m/L = H'2*atm 50.37 m/L = H 2*atm H 2 = 0.01986 atm-L/mole B.12.ESTIMATE H3 FROM GIBBS FREE ENERGY METHOD From enthalpy and entropy data i n Stumm and Morgan (1981), one can c a l c u l a t e the e q u i l i b r i u m constant between the aqueous and gas phases of ammonia. . Species H f (Kcal/mol) S (Kcal/K-mol) NH 3|g -11 .04 46.01E-03 \\ NH 3|aq -19.32 26.30E-03 An example c a l c u l a t i o n at 25 degrees : H = -19.32 - (-11.04) = -8.28 Kcal/mol S = 26.30 - 46.01 = -19.7 cal/K-mol . T S = (298.16)*(-19.7) = -5.88 Kcal/mol The r e f o r e the standard f r e e energy change i s based on Gibbs Free Energy below: A G ° = H - TAS = -8.28 - (-5.88) = -2.40 Kcal/mol So H^ i s c a l c u l a t e d from e q u i l i b r i u m e x p r e s s i o n below: -RTlnK = AG° . Where R = 1.987E-03 Kcal/K-mol l o g K = -AG0 2.303*T*R 227 . l o g K = 2.40/1.364 = 1.76 K or H =57.3 K = [ N H 3 | a q ] / P N H 3 = 57.5 mol/atm-L H 3 = 1.73E-02 atm-L/mol B. 1 3.CALCULATE H4 FROM THE SOLUBILITY EQUILIBRIUM METHOD ., T h i s method c a l c u l a t e s a dimensionless constant as a r a t i o between the aqueous and gaseous m o l a r i t i e s of ammonia. T h i s can then be converted to the a p p r o p r i a t e u n i t s . H 4 = [NH 3|aq]/[NH 3|g] In pure water s t u d i e s by Hale and Drewes (1979), Over 30 data p a i r s were regressed as a f u n c t i o n of temperature and i s shown below: lo g H 4 = -1.694 + 1477.7/T where T = K 2 No r was given and s t d . e r r o r was 9.7 % Example of conver s i o n to a p p r o p r i a t e u n i t s at 25 degrees: H 4 = 1842.0 [NH 3|g] = 1842 * [NH 3|aq] / H 4 Xg = [NH 3|g]/22.4 m/L and assume 1 atm pressure get: H. = 2.443E-5 atm-L/mole, which i s s i g n i f i c a n t l y l e s s than the other henry's c o n s t a n t s d i s c u s s e d so f a r , B.14.DESCRIPTION AND DERIVATION OF THIBODEAUX'S MODEL FOR GAS EMISSIONS FROM COVERED LANDFILLS WITH INTERNAL LANDFILL PRESSURE BUILD-UP. a. For a uniform composition of gas w i t h i n a l a n d f i l l c e l l , the equation of c o n t i n u i t y can be expressed below: n\"dC = - C*v + r ( i ) , dt • ~h~ . 9 Where n = a i r - f i l l e d p o r o s i t y 3 C = c o n c e n t r a t i o n i n ug/m t = time (days) v = s u p e r f i c i a l outward v e l o c i t y (m/day) h = l a n d f i l l c e l l depth (m) 3 r = r a t e of gas genera t i o n i n c e l l , (ug/m -day) b. The equation that d e s c r i b e s the one-dimensional flow of 226 gas through the c e l l or l a n d f i l l cover i s by Darcy's Law below: v = K *(p - b) ( i i ) u*L Where v = m/day u = gas v i s c o s i t y (cP) 2 R = pe r m e a b i l i t y , of cover (m /day) L = t h i c k n e s s of cap (m) p = pressure w i t h i n cap b = barometric pressure at l a n d f i l l s u r f a c e So t h i s equation d e s c r i b e s c o v e c t i o n flow caused by pressure induced flow. Combining equations i , i i and a b i o l o g i c a l gas rate ( r g ) , one can get an ex p r e s s i o n f o r the r a t e of change of i n t e r n a l l a n d f i l l p r e s s u r e . To get t h i s e x p r e s s i o n , the gas d e n s i t y must be solved using the i d e a l gas law. The ex p r e s s i o n i s below: dP = rg.*e*p - Kp(p-b) ( i i i ) dt n n*h*L*u Equation ( i i ) can be combined with the below equation that d e s c r i b e s steady s t a t e i n t e r n a l gas flow i n one d i r e c t i o n . De*d 2C - v*dC = 0 ( i v ) dZ dZ Where De i s e f f e c t i v e d i f f u s i o n c o e f f i c i e n t If h and z = s u r f a c e and base of l a n d f i l l cover, then can solve the above equation by i n t e g r a t i n g at boundary c o n d i t i o n s of Ca at z and C at h to get: C 9 = Ca - (Ca - C^)*(1-exp(z*v/De)) \"(v) z • (1-exp(h*v/De)) The f l u x e x p r e s s i o n then i s : Na = v * Ca - C^ + v*Ca ( v i ) exp(h*v/Da) - 1 T h i s expression c o n t a i n s both a d i f f u s i v e and co n v e c t i v e f l u x term. Equation ( v i ) i s then converted i n t o the more workable equation that by i t s e l f i s used to estimate f l u x emission r a t e s from l a n d f i l l s that are assumed to have 229 no i n t e r n a l pressure b u i l d - u p . T h i s i s shown below: Na = (De/L')*(Ca - C2)*(Rexp(R)) ( v i i ) (exp(R) - 1) ...... Where L = L a n d f i l l cover t h i c k n e s s (m) R = L*v/De Na = Mass f l u x i n M/L 2-T B. 15. SAMPLE CALCULATION OF.'THIBODEAUX'S MODEL, RICHMOND LANDFILL a. C a l c u l a t e E f f e c t i v e d i f f u s i o n c o e f f i c i e n t wi,th d i f f u s i o n c o e f f i c i e n t i n a i r (Do) = 1.750 irT/day and a i r - f i l l e d p o r o s i t y = 0.40 De = Do*(n 1 * 3 3 ) = 0.517 m 2/day 3 b. C a l c u l a t e G - f a c t o r R = L*v/De where L - 1.5m and v = 0.5996 m/day R = 1.74 G-Factor = 2.11 c. C a l c u l a t e NH^-N f l u x from gas N = (0.517 m 2/day/l.5M)*(92.8-20.0)*2.11 N = 52.9 ug NH3-N/m2-day The r e s u l t s f o r without gas gener a t i o n ( i e , Farmer's model) N = 25.1 ug NH3-N/m2-day d. C a l c u l a t e annual f l u x from the l a n d f i l l 52.9 * 200,000 m2 * 365 day/yr / 1 X 10 9 ug/kg N = 3.862 kg/yr B.16.SAMPLE CALCULATION OF GAS GENERATION MASS BALANCE MODEL AT RICHMOND LANDFILL 3 a. Assume gas pumping r a t e of 20.5 m /min and an ammonia gas c o n c e n t r a t i o n of 92.8 ug/m . 20.5 m3/min * 92.8 ug/m3 = 1902.5 ug/min 1902.5 ug/min * 1440 min/day * 1 X 10- 9 kg/ug. 230 = 0.00273 kg NK 3/day = 1.00 kg NH 3/year Check c a l c u l a t i o n of gas p r o d u c t i o n r a t e used i n Thibodeaux model run. Get refuse mass = 200,000 m2 * 1 0 m * 600 kg/m3 = 1.2 X 10 9 kg of r e f u s e f i l l 20.5 m3/min = 2.95 X 1 0 1 0 mL/day Therefore gas p r o d u c t i o n r a t e = f l o w / r e f u s e mass = 24.6 mL/kg-day which compares to assumed value 40 mL/kg-day used i n model runs. 231 Vancouver I n t l . A i r p o r t Vancouver Harbor Abbotsford Aug. 87 0.0 Tr 0.0 25.8 15.0 13.9 0.0 0.2 0.0 Tr Tr Tr Sept. 87 13.2 11.4 11.6 9.6 11.1 12.0 2.2 0.0 0.0 3.4 5.6 1.4 Oct. 87 0.2 1.2 1.6 0.0 0.0 0.0 0.0 Tr Tr 20.2 31.4 18.2 Nov. 87 0.6 5.2 1.8 74.8 91.1 69.0 48.4 77.5 31.5 13.0 9.0 9.0 Dec. 87 73.0 137.9 95.8 46.4 48.6 73.8 16.6 32.0 28.8 13.6 10.6 15.1 Jan. 88 0.0 0.0 0.0 40.8 83.4 75.1 15.8 16.4 15.9 9.6 16.6 19.8 Feb. 88 18.3 32.8 40.0 46.2 77.1 57.9 3.6 9.4 6.2 3.6 6.0 3.4 Mar. 88 25.2 32.1 33.3 23.0 35.3 26.6 43.0 53.6 33.7 47.0 63.7 61.1 Apr. 88 71.6 n.d. 105.6 Tr n.d. Tr 2.4 n.d. 8.2 17.2 n.d. 48.0 NOTE: P r e c i p i t a t i o n i n m i l l i m e t e r s APPENDIX C.I.- Weekly P r e c i p i t a t i o n Data For Weather Stations i n Close Proximity to L a n d f i l l Study S i t e s . Note: Vancouver Harbour was Permanently Discontinued at the End of Marcn, 1988. 232 APPENDIX D - TABLES OF BASIC DATA FROM EACH SAMPLE WELL DATE B . L . TEW TEW pH KH3-X SPEC. NH3-N I CH4 Z C02 1 N2 I 02 6AS BAftO. ( i t t t r s ) LEACH 6AS LEACH CONDUCT. 6AS aoii PRESS. £2£===SSS --—T77Tr— --------- (•OA) ( U I B O / C I ) (ppb) ( L / i i n ) g a u a g a u a ) ( u g / L ) 08/05/87 10.62 2.4132 08/25/87 10.92 5.9866 09/08/87 10.86 4.8962 09/22/87 10.70 4.9803 10/06/87 15.82 3.5527 10/20/87 12.18 2.9773 11/10/87 9.81 3.5430 11/24/87 3.92 4.1266 12/08/87 4.57 1.5385 12/29/87 3.75 1.2970 01/12/88 8.86 1.8128 01/26/88 9.13 4.0341 02/09/88 4.49 2.2008 03/01/88 8.24 1.4104 03/29/88 6.64 0.5491 F l MATSQUI 5.6390 1.281 — 12.2826 1.247 — 10.7100 1.262 — 11.3468 1.273 — 8.3534 1.278 — 6.8552 1.273 — 8.3634 1.278 — 9.1664 1.271 — 3.2180 1.258 — 2.5868 1.241 — 5.4996 1.329 0.3846 11.6714 1.322 0.3392 4.3601 1.243 0.3608 2.6823 1.229 0.2606 1.1397 1.255 0.2564 0.64 9.84 4.87 0.65 9.70 4.86 0.64 9.72 4.86 0.68 9.60 4.86 0.68 9.70 4.86 14.71 4.95E-05 843.4 14.56 4.95E-05 843.5 14.58 3.83E-05 653.5 14.46 3.66E-05 623.4 14.56 2.45E-05 417.3 08/05/87 9.84 2.3305 08/25/87 3B.67 3.3734 09/08/87 17.60 3.0726 09/22/87 33.50 3.9670 10/06/87 38.09 4.4313 10/20/87 59.86 3.5811 11/10/87 19.45 3.7221 11/24/87 12.49 3.1797 12/08/87 12.69 2.5878 12/29/87 13.74 2.2630 01/12/88 12.79 2.5750 01/26/88 11.23 3.2884 02/09/88 14.50 1.7290 03/01/88 15.37 2.1516 03/29/88 14.15 3.5634 F2 MATSMIl 5.7779 1.288 0.0640 10.7900 1.948 0.05B2 9.4654 1.317 0.0544 11.4527 1.310 0.0491 13.1316 1.311 0.0578 10.8311 1.315 0.0540 11.2235 1.314 0.0539 10.1509 1.322 0.0512 7.6950 1.311 0.0384 6.2768 1.301 0.0434 7.7794 1.310 0.0289 10.0229 1.312 0.0173 5.5165 1.320 0.0179 6.4609 1.310 0.0472 7.6946 1.259 0.0223 0.79 9.50 4.85 0.80 9.50 4.85 0.80 9.47 4.85 0.81 9.50 4.85 0.80 9.47 4.85 0.80 9.50 4.85 0.80 9.54 4.85 0.80 9.54 4.85 0.82 9.70 4.86 0.82 9.70 4.86 0.84 9.81 4.86 0.87 9.64 4.86 0.87 9.59 4.86 0.81 9.64 4.86 0.86 9.64 4.86 14.35 8.33E-05 1419.7 14.35 6.57E-05 1119.3 14.32 8.95E-05 1524.6 14.35 9.10E-05 1551.0 14.32 1.14E-04 1940.5 14.35 1.17E-04 1998.9 14.39 1.46E-04 2491.3 14.39 4.24E-04 7229.3 14.56 4.25E-06 72.4 14.56 4.17E-05 710.0 14.67 1.13E-05 192.9 14.49 1.83E-06 31.2 14.44 7.48E-07 12.7 14.49 3.78E-05 643.5 14.49 2.04E-05 347.9 244 APPENDIX E DATE M2/02^ CH4 FLUX C02 FLUX GAS IONIC ACTIVITY pKa p K l pKw NH3-N NH3-N RATIO ( k g CH4/ (kg CQ2/ OENSITY STRENGTH COEFF. ( • o l a r tt 6AHHA d a y - c i 2 ) d a y - c i 2 ) (kg/a3> g a u a g a n a ) ( u g / L ) F3 HATSQUI 08/05/87 6.54 10.0341 16.4176 1.185 — — — — — — 08/25/87 12.94 10.8426 22.8999 1.254 - • — — — 09/08/87 13.89 11.6540 22.5291 1.230 - — — — — — 09/22/87 9.58 13.4525 25.6523 1.226 • — — — — 10/06/87 19.75 13.5262 27.2305 1.240 — — — — 10/20/87 10.67 10.4762 21.4898 1.247 - — — 11/10/87 8.47 12.1526 24.5528 1.240 -- — — — — 11/24/87 11.00 11.0818 23.1808 1.252 .— — — — — 12/08/87 7.11 8.8697 17.4326 1.239 0.0544 0.80 9.74 4.86 14.60 3.36E-05 572.7 12/29/87 6.84 7.9866 14.6359 1.221 0.0497 0.81 9.74 4.86 14.60 1.97E-05 336.2 01/12/88 6.83 9.8026 20.8939 1.258 0.0329 0.83 9.74 4.86 14.60 1.15E-05 195.4 01/26/88 4.60 13.5229 24.0213 1.21B 0.0266 0.85 9.60 4.86 14.46 7.94E-06 135.4 02/09/88 8.98 2.2782 6.0200 1.292 0.0269 0.85 9.60 4.86 14.46 2.71E-06 46.2 03/01/88 4.88 9.4767 16.0242 1.200 0.0221 0.86 9.50 4.85 14.35 1.14E-06 19.4 03/29/88 10.04 9.0361 16.3960 1.221 0.0208 0.86 9.64 4.86 14.49 2.43E-06 41.4 F4 HATSBUI 08/05/87 — 4.2073 7.5106 1.203 — — — — — 08/25/87 8.50 7.9501 14.9377 1.225 ' — — -- — 09/08/87 3.75 7.8669 12.9114 1.183 — — — — 09/22/87 4.88 8.6947 14.3266 1.184 — -- — 10/06/87 — 7.6412 15.1786 1.235 — — « 10/20/87 16.25 5.5380 11.2325 1.241 — — — — — 11/10/87 8.29 5.7324 12.2344 1.258 — « • ~ — — 11/24/87 7.37 4.8311 10.5278 1.264 ~ — — — — 12/08/87 7.45 2.9892 7.1125 1.285 • — — — — 12/29/87 9.90 4.0067 7.6979 1.228 — • — — — — 01/12/88 12.00 6.8247 12.3824 1.215 — — — — 01/26/88 6.53 6.9729 13.2046 1.226 — — --> — — 02/09/88 — — -- — — — — — -- — 03/01/88 6.11 1.0880 2.1201 1.237 ~ — — — --03/29/88 4.86 2.1121 4.0369 1.234 — — — — — — 245 APPENDIX E DATE N2/02 CH4 FLUX C02 FLUX 6AS IONIC ACTIVITY pKa p K l pKv NH3-N NH3-N RATIO (kg CH4/ ( k g C02/ DENSITY STRENGTH COEFF. ( • o l a r U/ 6AHMA d a y - c i 2 ) d a y - c i 2 ) ( k g / i 3 ) g a u a g a n a ) ( u g / L ) F5 MATSQUI • 08/05/87 24.00 2.4950 5.9775 1.281 0.1920 0.70 9.50 4.85 14.35 4.53E-05 771.4 08/25/87 — 2.0322 4.2226 1.247 0.3506 0.65 9.47 4.85 14.32 1.79E-04 3045.0 09/08/87 1.9744 4.1025 1.247 0.2960 0.66 9.50 4.85 14.35 1.89E-04 3228.2 03/22/85 — 2.5079 5.1898 1.245 0.2807 0.67 9.50 4.85 14.35 1.26E-04 2139.7 10/06/87 3.92 4.1188 8.4110 1.245 0.3073 0.66 9.47 4.85 14.32 2.10E-04 3581.4 10/20/87 11.75 2.4347 4.0707 1.185 0.3020 0.66 9.50 4.85 14.35 1.63E-04 2779.2 11/10/87 3.43 4.7518 9.3998 1.234 0.0954 0.76 9.57 4.85 14.42 3.46E-05 589.2 11/24/87 3.57 — -- 1.252 0.0465 0.81 9.60 4.86 14.46 5.29E-07 9.0 12/08/87 4.80 0.8104 1.7367 1.259 0.0512 0.80 9.60 4.86 14.46 1.04E-06 17.7 12/23/87 3.54 1.1131 2.0447 1.213 0.2359 0.68 9.60 4.86 14.46 7.66E-05 1305.6 01/12/88 4.26 4.1885 7.5049 1.214 0.3061 0.66 9.62 4.86 14.48 1.49E-04 2537.8 01/26/88 3.50 5.7427 10.1948 1.208 0.0705 0.78 9.59 4.86 14.44 5.94E-06 101.3 02/09/88 — — — — 0.0458 0.81 9.67 4.86 14.53 5.12E-06 87.3 03/01/88 3.80 0.0000 0.0000 1.323 0.1569 0.72 9.57 4.85 14.42 3.87E-05 660.2 03/29/88 — — — — 0.1028 0.75 9.60 4.86 14.46 1.40E-05 237.9 F6 HATSQUI 08/05/87 3.89 0.3332 0.5921 1.236 08/25/87 — — -- --09/08/87 3.74 0.0000 0.0000 1.235 — 09/22/85 3.49 0.0000 0.0000 1.262 _ 10/06/87 4.50 2.9992 5.3732 1.207 10/20/87 4.42 1.2877 2.3236 1.209 — 11/10/87 3.89 1.8955 3.5562 1.221 — F 8 HATSQUI 11/10/87 4.35 0.0949 0.2167 1.279 0.0138 0.88 9.50 4.85 14.35 4.48E-09 0.1 11/24/87 4.15 1.5534 3.4350 1.275 0.0047 0.93 9.57 4.85 14.42 8.26E-10 0.0 12/08/87 4.85 0.2045 0.5474 1.284 0.0064 0.92 9.65 4.86 14.51 6.90E-10 0.0 12/29/87 3.63 0.1855 0.3218 1.255 0.0091 0.90 9.65 4.86 14.51 1.87E-08 0.3 01/12/88 3.69 0.3167 0.6368 1.263 0.0060 0.92 9.77 4.86 14.63 5.13E-09 0.1 01/26/88. 3.77 0.2733 0.6624 1.161 0.0070 0.91 9.74 4.86 14.60 9.53E-09 0.2 02/09/88 3.52 0.3529 0.5044 1.206 0.0164 0.87 9.84 4.87 14.71 8.04E-09 0.1 03/01/88 3.68 0.0585 0.0921 1.241 0.0099 0.90 9.70 4.86 14.56 — 03/29/88 4.77 0.0604 0.1314 1.271 0.0039 0.93 9.77 4.86 14.63 — 246 APPENDIX E DATE N2/02 CH4 FLUX C02 FLUX GAS IONIC ACTIVITY pKa pKI pKv NH3-N NH3-N RATIO (kg CH4/ ( k g C02/ DENSITY STREN6TH COEFF. ( a o l a r H7 6AHHA d a y - c » 2 ) d a y - c « 2 ) ( k g / a 3 ) g a i a a g a n a ) (u g / L ) 08/09/87 5.80 0.4864 08/27/87 13.15 0.2109 09/10/87 24.44 0.0915 09/24/87 5.90 0.3737 10/07/87 12.25 0.2553 10/22/87 9.65 0.3374 11/12/87 7.67 0.6435 11/26/87 12.05 1.3893 12/15/87 13.58 0.3119 12/31/87 7.04 0.0000 01/14/88 21.40 4.3944 01/28/88 7.40 0.2409 02/11/88 8.35 0.4795 03/03/88 3.83 0.0000 03/31/88 52.00 0.1107 F2 STRIDE 0.3698 1.062 0.167S 1.068 0.0189 0.0716 1.049 0.0184 0.3438 1.113 0.0156 0.3471 1.147 0.0187 0.2674 1.057 0.0180 0.5048 1.070 0.0177 1.0039 1.045 0.0152 0.4118 1.190 0.0126 0.0000 1.130 0.0177 4.0592 1.073 0.0165 0.5854 1.281 0.0203 0.5134 1.150 0.0213 0.0000 1.259 0.0199 0.1839 1.215 0.0215 — 9.67 4.86 0.87 9.60 4.86 0.87 9.60 4.86 0.88 9.57 4.85 0.87 9.60 4.86 0.87 9.67 4.86 0.87 9.67 4.86 0.88 9.69 4.86 0.89 9.69 4.86 0.87 9.69 4.86 0.87 9.69 4.86 0.86 9.65 4.86 0.86 9.67 4.86 0.S7 9.65 4.86 0.86 9.67 4.86 14.53 7.45E-08 1.3 14.46 4.68E-08 0.8 14.46 1.25E-07 2.1 14.42 9.09E-08 1.5 14.46 7.79E-08 1.3 14.53 2.05E-08 0.3 14.53 5.61E-08 1.0 14.55 3.91E-09 0.1 14.55 3.56E-09 0.1 14.55 4.71E-08 0.8 14.55 4.90E-08 0.8 14.51 9.46E-08 1.6 14.53 1.17E-07 2.0 14.51 1.11E-07 1.9 14.53 7.43E-08 1.3 F3 STRIDE 08/09/87 25.40 0.2053 08/27/87 17.86 0.2184 09/10/87 21.00 0.1732 09/24/87 4.33 0.0000 10/07/87 10.60 0.4345 10/22/87 17.00 0.4660 11/12/87 7.77 0.9075 11/26/87 10.08 1.1306 12/15/87 8.57 0.3144 12/31/87 7.49 0.0000 01/14/88 6.29 0.1813 01/28/88 4.38 0.0641 02/11/88 4.76 0.2219 03/03/88 3.81 0.0000 03/31/88 9.91 0.0962 0.1692 1.067 0.1707 1.058 0.0160 0.1412 1.050 0.0160 0.0000 1.169 0.0133 0.5444 1.130 0.0165 0.3375 1.039 0.0159 0.6644 1.065 0.0130 0.8235 1.051 0.0317 0.3134 1.117 0.0175 0.0000 1.078 0.0135 0.1381 1.093 0.0080 0.0547 1.190 0.0156 0.1694 1.149 0.0134 0.0000 1.220 0.0096 0.1299 1.212 0.0163 — 9.67 4.86 0.88 9.67 4.86 0.88 9.67 4.86 0.89 9.64 4.86 0.87 9.67 4.86 0.88 9.69 4.86 0.89 9.67 4.86 0.84 9.69 4.86 0.87 9.67 4.86 0.88 9.65 4.86 0.91 9.67 4.86 0.88 9.65 4.86 0.89 9.65 4.86 0.90 9.67 4.86 0.88 9.64 4.86 14.53 1.78E-07 3.0 14.53 5.43E-08 0.9 14.53 1.19E-07 2.0 14.49 1.32E-07 2.2 14.53 1.07E-07 1.8 14.55 l.OOE-07 1.7 14.53 1.57E-07 2.7 14.55 1.16E-07 2.0 14.53 7.75E-08 1.3 14.51 9.17E-08 1.6 14.53 2.45E-08 0.4 14.51 1.26E-07 2.2 14.51 1.08E-07 1.8 14.53 1.38E-07 2.4 14.49 2.02E-07 3.4 F6 STRIDE 10/22/87 3.99 0.1042 0.2035 1.263 0.0336 0.83 9.62 4.86 14.48 3.81E-07 6.5 11/12/87 3.73 0.0440 0.0556 1.266 0.0149 0.88 9.60 4.86 14.46 2.67E-07 4.5 11/26/87 3.71 0.0000 0.0089 1.293 0.0160 0.88 9.65 4.86 14.51 5.47E-08 0.9 12/15/87 3.65 0.0000 0.0028 1.289 0.0171 0.87 9.65 4.86 14.51 5.52E-08 0.9 12/31/87 3.61 0.0000 0.0000 1.287 0.0120 0.89 9.74 4.86 14.60 1.25E-07 2.1 01/14/88 3.85 0.0000 0.2744 1.487 0.0119 0.89 9.74 4.86 14.60 8.17E-08 1.4 01/28/88 — 0.0000 0.0129 0.588 0.0134 0.88 9.69 4.86 14.55 1.40E-07 2.4 02/11/88 -- — — — 0.0157 0.88 9.70 4.86 14.56 1.40E-07 2.4 03/03/88 3.67 0.0000 0.0000 1.286 0.0133 0.89 9.69 4.86 14.55 1.34E-07 2.3 247 APPENDIX E DATE N2/02 CH4 FLUX C02 FLUX SAS IONK ACTIVITY pKa p K l pKw J I H 3 - H NH3-N RATIO (kg CH4/ ( k g C02/ DENSITY STREKSTH COEFF. d o l a r U/ 6AHHA d a y - c a 2 ) d a y - c i 2 ) ( k g / i 3 ) g a u a g a i t a ) ( u g / L ) F7 STRIDE 08/27/87 14.50 0.2470 0.3067 1.134 0.0174 0.87 3.60 4.86 14.46 3.33E-07 6.7 03/10/87 8.81 0.3203 0.3503 1.106 0.0163 0.87 3.57 4.85 14.42 5.56E-07 3.5 03/24/87 -- ~ — ~ 0.0143 0.88 3.60 4.86 14.46 2.34E-07 5.0 10/07/87 10.31 1.0143 1.0333 1.080 0.0155 0.88 3.67 4.86 14.53 2.46E-07 4.2 10/22/87 3.67 1.7384 1.8088 1.088 0.0156 0.88 3.60 4.86 14.46 2.42E-07 4.1 11/12/87 12.62 2.4742 3.3354 1.153 0.0135 0.88 3.62 4.86 14.48 4.05E-07 6.3 11/26/87 15.00 2.3384 4.1741 1.175 0.0103 0.30 3.64 4.86 14.43 3.44E-08 0.6 12/15/87 31.20 0.7152 0.7555 1.088 0.0218 0.86 3.57 4.85 14.42 3.24E-07 5.5 12/31/87 6.33 0.0000 0.0000 1.175 0.0133 0.86 3.60 4.86 14.46 2.35E-07 5.0 01/14/88 — 0.3707 0.4452 1.130 0.0187 0.87 3.57 4.85 14.42 3.43E-07 5.8 01/28/88 3.82 0.1541 0.0653 1.054 0.0173 0.87 3.60 4.86 14.46 2.73E-07 4.7 02/11/88 4.18 1.0130 0.4051 0.354 0.0208 0.86 3.60 4.86 14.46 4.40E-07 7.5 03/03/88 4.02 0.0000 0.0000 1.111 0.0205 0.87 3.53 4.86 14.44 1.07E-06 18.2 03/31/88 4.33 0.1408 0.2450 1.244 0.0183 0.87 3.53 4.86 14.44 5.74E-07 3.8 F 8 STRIDE 08/27/87 10.35 0.2538 0.3327 1.143 — — — — — 03/10/87 10.80 0.2462 0.2836 1.116 — — — -- — 03/24/87 13.44 0.7127 0.7883 1.034 — — — ~ --10/07/87 3.12 0.1441 0.1887 1.151 — — — — -- — 10/22/87 4.23 0.2780 0.3633 1.221 — -- — — — 11/12/87 5.70 0.4340 0.5715 1.204 — — — — -- — 11/26/87 3.04 1.4431 1.8473 1.150 ~ — — -- — — 12/15/87 5.03 0.7646 1.7644 1.277 0.01 0.88 3.67 4.86 14.53 1.13E-08 0.2 12/31/87 6.76 0.0000 0.0000 1.044 0.01 0.83 3.67 4.86 14.53 5.83E-08 1.0 01/14/88 — 2.0217 2.1366 ° 1.078 0.02 0.83 9.67 4.86 14.53 7.87E-08 1.3 01/28/88 4.06 0.4568 0.4823 1.114 0.01 0.83 9.67 4.86 14.53 2.55E-08 0.4 02/11/88 4.27 1.0284 0.6553 1.033 0.01 0.30 3.74 4.86 14.50 1.21E-08 0.2 03/03/88 ~ — — ~ 0.01 0.94 3.67 4.86 14.53 1.54E-08 0.3 03/31/88 5.44 0.2215 0.2313 1.203 0.01 0.94 9.74 4.86 14.50 2.28E-08 0.4 10B STRIDE 08/03/87 42.25 0.0527 0.3558 1.416 — — 3.60 4.86 14.46 2.61E-08 0.4 08/27/87 13.13 0.0000 0.0000 1.365 0.0220 0.86 3.60 4.86 14.46 1.55E-08 0.3 03/10/87 14.31 0.0360 0.1524 1.360 0.0234 0.86 3.64 4.86 14.43 3.52E-08 0.6 03/24/87 28.05 0.0721 0.3620 1.363 0.0184 0.87 3.64 4.86 14.49 1.83E-08 0.3 10/07/87 16.26 0.0838 0.3181 1.351 0.0234 0.86 3.64 4.86 14.43 2.24E-08 0.4 248 APPENDIX E DATE N2/02 CH4 FLUX C02 FLUX GAS IONIC ACTIVITY pKa pKI pKw NH3-N NH3-N RATIO ( k g CH4/ ( k g C02/ DENSITY STRENGTH COEFF. ( t o l a r U/ GAMMA d a y - c i 2 ) d a y - c a 2 ) ( k g / i 3 ) g a n a g a a i a ) ( u g / L ) B8 RICHMOND 08/14/87 9.33 0.6194 09/01/87 — 2.2061 09/15/87 3.78 1.5352 09/29/87 3.33 0.9756 10/13/87 3.89 1.0945 11/03/87 3.62 0.5315 11/17/87 3.71 0.5048 12/01/87 3.44 1.6503 12/24/87 3.53 4.9235 01/06/88 3.49 4.2049 01/19/88 3.90 2.7110 02/02/88 3.53 2.0550 02/24/88 -- 4.2146 03/15/88 3.50 6.8759 04/05/88 8.80 5.6335 1.2944 1.249 4.6972 1.254 0.0528 3.2875 1.258 0.0618 2.0718 1.254 0.0629 2.3627 1.259 0.0768 1.1909 1.272 0.0706 1.0668 1.253 0.0421 3.7100 1.272 0.0336 10.8735 1.270 0.0274 9.1781 1.267 0.0244 5.7989 1.259 0.0219 4.6861 1.280 0.0281 8.8649 1.265 0.0096 14.4970 1.256 0.0149 12.3750 1.264 0.0177 ~ 9.44 4.84 0.80 9.41 4.84 0.79 9.44 4.84 0.79 9.41 4.84 0.77 9.44 4.84 0.78 9.41 4.84 0.82 9.46 4.85 0.83 9.52 4.85 0.85 9.59 4.86 0.85 9.57 4.85 0.86 9.60 4.86 0.84 9.72 4.86 0.90 9.64 4.86 0.88 9.60 4.86 0.87 9.69 4.86 14.28 5.54E-06 94.3 14.25 6.35E-06 108.2 14.28 1.20E-05 205.2 14.25 1.01E-05 172.4 14.28 1.12E-05 191.4 14.25 2.50E-05 426.6 14.30 2.66E-06 45.2 14.37 3.89E-07 6.6 14.44 5.30E-07 9.0 14.42 8.40E-07 14.3 14.46 6.29E-07 10.7 14.58 8.93E-07 15.2 14.49 1.31E-07 2.2 14.46 1.86E-07 3.2 14.55 1.42E-07 2.4 09 RICHMOND 08/14/87 2.60 9.1606 09/01/87 3.75 10.1367 09/15/87 3.73 8.8003 09/29/87 3.67 9.0131 10/13/87 — 5.0442 11/03/87 3.65 6.1105 11/17/87 3.71 11.4659 12/01/87 3.33 17.5201 12/24/88 3.52 12.8878 01/06/88 3.43 12.1224 01/19/88 3.94 9.5274 02/02/88 3.90 13.9014 02/24/88 — 16.1134 03/15/88 3.84 16.1723 04/05/88 3.77 14.0726 20.2373 1.267 — 22.1815 1.263 0.1336 19.2026 1.263 0.1389 19.6269 1.264 0.1302 10.8279 1.257 0.1246 13.8992 1.277 0.1051 25.2854 .1.267 0.0952 39.1946 1.271 0.0517 27.3986 1.260 0.0200 25.6654 1.260 0.0943 19.4146 1.243 0.0428 28.6588 1.250 0.1199 32.9389 1.242 0.1277 32.3461 1.241 0.1679 29.9001 1.260 0.08S8 — 9.19 4.81 0.73 9.19 4.81 0.73 9.22 4.82 0.73 9.19 4.81 0.74 9.22 4.82 0.75 9.22 4.82 0.76 9.16 4.81 0.80 9.17 4.81 0.86 9.22 4.82 0.76 9.22 4.82 0.82 9.31 4.83 0.74 9.28 4.83 0.73 9.27 4.82 0.71 9.25 4.82 0.77 9.41 4.84 14.00 1.01E-04 1723.9 14.00 7.41E-05 1262.8 14.04 6.23E-05 1061.5 14.00 8.3BE-05 1427.5 14.04 4.41E-04 7508.3 14.04 1.48E-04 2520.8 13.97 7.97E-05 1358.6 13.98 1.04E-05 177.2 14.04 4.29E-07 7.3 14.04 5.18E-05 882.0 14.14 5.24E-06 89.2 14.11 7.00E-05 1192.0 14.09 8.32E-05 1417.8 14.07 1.50E-04 2563.9 14.25 2.01E-05 343.3 249 DATE N2/02 CH4 F L U * C02 FLUX RATIO ( k g CH4/ ( k g C02/ d a y - c « 2 ) d a y - c « 2 ) 08/14/87 3.71 13.2513 28.5034 09/01/87 3.89 19.1247 42.1674 09/15/87 — 4.6480 10.2645 09/29/87 3.71 9.4894 20.4974 10/13/87 — 6.0962 13.2462 11/03/87 3.65 7.9978 17.6211 11/17/87 3.75 16.9012 36.0403 12/01/87 3.30 5.0170 10.7919 12/24/87 3.30 1.9622 4.1829 01/06/88 3.69 1.7202 3.5515 01/19/88 4.28 2.2144 4.7688 02/02/88 3.84 20.3343 43.5387 02/24/88 — 21.4123 43.9500 03/15/88 31.5596 64.7780 04/05/88 4.15 29.1100 59.1447 APPENDIX E ,8AS IONIC ACTIVITY pKa DENSITY STRENGTH COEFF. ( k g / i 3 ) g a i i a C6 RICHMOND 1.258 — — 9.31 1.266 0.0437 0.82 9.28 1.265 0.0452 0.81 9.31 1.259 0.0431 0.82 9.31 1.260 0.0477 0.81 9.25 1.267 0.0438 0.82 9.28 1.255 0.0261 0.85 9.28 1.260 0.0308 0.84 9.46 1.260 0.0284 0.84 9.59 1.252 0.0247 0.85 9.60 1.263 0.0265 0.85 9.54 1.262 0.034B 0.83 9.57 1.260 0.0296 0.84 9.57 1.248 0.0363 0.83 9.38 1.243 0.0366 0.83 9.54 p K l pKw NH3-N NH3-N ( t o l a r U/ 6AHHA g a t i a ) ( u g / L ) 4.83 14.14 2.65E-06 45.1 4.83 14.11 1.74E-06 29.6 4.83 14.14 2.87E-06 48.9 4.83 14.14 3.74E-07 6.4 4.82 14.07 4.29E-07 7.3 4.83 14.11 2.56E-06 43.7 4.83 14.11 8.81E-08 1.5 4.85 14.30 1.29E-07 2.2 4.86 14.44 2.48E-07 4.2 4.86 14.46 1.47E-07 2.5 4.85 14.39 2.68E-07 4.6 4.85 14.42 3.67E-07 6.3 4.85 14.42 4.37E-07 7.4 4.84 14.21 5.13E-07 8.7 4.85 14.39 7.82E-08 1.3 08/14/87 3.75 I.04B5 09/01/87 3.91 2.0611 09/15/87 -- 0.4193 09/29/87 3.80 1.2439 10/13/87 3.73 0.8434 11/03/87 3.58 1.1172 11/17/87 3.71 2.3337 12/01/87 3.43 1.1475 12/24/87 3.81 0.2031 01/06/88 3.65 1.0686 01/19/88 4.37 0.4070 02/02/88 4.00 1.9342 02/24/88 4.08 0.7578 03/15/88 4.05 2.6835 04/05/88 67 2.1733 1.261 — 4.5038 1.262 0.0548 0.8819 1.250 0.0610 2.5775 1.247 0.0601 1.7901 1.261 0.0644 2.3787 1.258 0.0651 5.1322 1.267 0.0667 2.4342 1.257 0.0402 0.4236 1.254 0.0224 2.4342 1.277 0.0234 0.8722 1.390 0.0210 4.1175 1.261 0.0294 1.5866 1.256 0.0184 5.4959 1.245 0.0259 — 0.0105 ~ 9.38 4.84 0.80 9.34 4.83 0.79 9.38 4.84 0.79 9.34 4.83 0.79 9.31 4.83 0.79 9.34 4.83 0.79 9.31 4.83 0.82 9.42 4.84 0.86 9.57 4.85 0.86 9.38 4.84 0.86 9.41 4.84 0.84 9.47 4.85 0.87 9.41 4.84 0.85 9.41 4.84 0.90 9.62 4.86 14.21 4.73E-06 80.6 14.18 5.33E-06 90.8 14.21 7.28E-06 124.0 14.18 9.88E-06 168.4 14.14 9.19E-06 156.6 14.18 1.71E-05 291.7 14.14 1.40E-05 238.8 14.27 1.42E-06 24.1 14.42 3.00E-07 5.1 14.21 9.32E-07 15.9 14.25 6.52E-07 11.1 14.32 6.23E-07 10.6 14.25 5.74E-07 9.8 14.25 6.34E-07 10.8 14.48 4.03E-08 0.7 250 DATE N2/02 CH4 FLUX C02 FLUX RATIO (kg CH4/ (kg C02/ d a y - c i 2 ) d a y - c i 2 ) APPENDIX E GAS IONIC ACTIVITY pKa DENSITY STRENGTH COEFF. (kg/t.3) g a n a p K l pKv NH3-N NH3-N ( • o l a r H/ GAMMA ga a a a ) ( u g / L ) 08/14/87 ~ 1.5045 3.2296 09/01/87 3.69 3.4906 7.1993 09/15/87 — 9.0341 18.5430 09/29/87 3.71 1.9279 3.9968 10/13/87 — 1.2005 2.5336 11/03/87 3.59 1.1797 2.4860 11/17/87 3.59 3.4266 7.2675 12/01/87 3.17 1.5514 3.2669 12/24/87 3.29 1.5907 3.1764 01/06/88 3.97 0.7010 1.8639 01/19/88 3.98 0.7975 2.0656 02/02/88 3.17 1.2558 2.9718 02/24/88 — 0.0000 0.5245 03/15/88 — 5.1718 10.2655 04/05/88 4.00 0.5254 1.0588 0.55 RICHMOND 1.255 — — 9.31 1.247 0.0679 0.78 9.28 1.243 0.0704 0.78 9.28 1.249 0.0687 0.78 9.25 1.250 0.0733 0.78 9.25 1.255 0.0647 0.79 9.25 1.256 0.0675 0.78 9.25 1.254 0.0626 0.79 9.41 1.238 0.0548 0.80 9.38 1.315 0.0604 0.79 9.33 1.308 0.0598 0.79 9.38 1.300 0.0634 0.79 9.44 1.288 0.0491 0.81 9.38 1.233 0.0559 0.80 9.44 1.240 0.0217 0.86 9.55 4.83 14.14 1.93E-05 329.7 4.83 14.11 1.68E-05 286.1 4.83 14.11 1.14E-05 195.0 4.82 14.07 1.22E-05 207.1 4.82 14.07 1.28E-05 217.5 4.82 14.07 1.75E-05 297.6 4.82 14.07 1.09E-05 184.9 4.84 14.25 9.43E-06 160.6 4.84 14.21 8.69E-06 148.1 4.83 14.16 1.28E-05 218.6 4.84 14.21 8.84E-06 150.6 4.84 14.28 4.84E-06 82.5 4.84 14.21 8.17E-06 139.2 4.84 14.28 4.55E-06 77.5 4.85 14.41 5.7BE-07 9.8 08/14/87 4.00 1.8997 5.4214 09/01/87 3.65 1.6986 3.7464 09/15/87 3.67 1.2820 2.8188 09/29/87 3.80 1.2284 2.6037 10/13/87 — 0.8817 1.9357 11/03/87 3.62 0.6937 1.4849 11/17/87 3.75 0.7789 1.6601 12/01/87 3.39 0.8030 1.7293 12/24/87 3.61 0.0709 0.1365 01/06/88 3.97 0.0000 0.0000 01/19/88 4.96 0.0488 0.1051 02/02/88 3.91 0.0000 0.0178 02/24/88 3.65 0.0000 0.0000 03/15/88 3.68 0.0000 0.0000 04/05/88 — — B.53 RICHMOND 1.339 — — 9.28 1.267 0.0549 0.80 9.28 1.267 0.0608 0.79 9.25 1.252 0.0538 0.80 9.25 1.264 0.0544 0.80 9.28 1.258 0.0419 0.82 9.22 1.257 0.0476 0.81 9.25 1.262 0.03B6 0.82 9.31 1.264 0.0316 0.84 9.47 1.275 0.0285 0.84 9.47 1.273 0.0254 0.85 9.60 1.276 0.0223 0.86 9.54 1.286 0.0105 0.90 9.49 1.327 0.0135 0.89 9.50 • — 0.0131 0.89 9.59 4.83 14.11 2.40E-05 409.2 4.83 14.11 1.27E-05 216.0 4.82 14.07 1.55E-05 264.0 4.82 14.07 1.03E-05 174.8 4.83 14.11 5.42E-06 92.4 4.82 14.04 7.25E-06 123.6 4.82 14.07 9.17E-06 156.3 4.83 14.14 3.30E-06 56.3 4.85 14.32 1.78E-06 30.4 4.85 14.32 1.97E-06 33.6 4.86 14.46 1.44E-06 24.6 4.85 14.39 6.12E-07 10.4 4.85 14.34 4.33E-07 7.4 4.85 14.35 1.89E-07 3.2 4.86 14.44 8.67E-08 1.5 251 DATE N2/02 CH4 FLUX C02 FLUX RATIO (kg CH4/ (kg C02/ d a y - « 2 ) d a y - « 2 ) 08/20/87 3.60 0.0282 0.0528 09/03/87 3.86 0.0329 0.0671 09/17/87 3.60 0.0619 0.1473 10/01/87 3.90 0.1876 0.3872 10/15/87 3.6S 0.1546 0.3142 11/05/87 3.64 0.1393 0.2813 11/19/87 3.54 0.1130 0.2248 12/03/87 3.61 0.0181 0.0442 12/22/87 3.66 0.0849 0.1708 01/05/88 3.58 0.0307 0.0730 01/20/88 3.64 0.0000 0.0478 02/04/88 3.90 0.0299 0.0681 02/23/88 3.62 0.0413 0.0813 03/17/88 3.76 0.0517 0.1048 04/07/88 3.63 0.0000 0.0058 APPENDIX E GAS IONIC ACTIVITY pKa DENSITY STRENGTH COEFF. ( k g / s 3 ) g a t n a PI PREMIER 1.259 0.1069 0.75 9.34 1.263 0.1042 0.75 9.31 1.287 0.1025 0.75 9.28 1.263 0.1002 0.75 9.34 1.265 0.1034 0.75 9.34 1.260 0.1046 0.75 9.33 1.267 0.0971 0.76 9.34 1.292 0.0875 0.76 9.38 1.269 0.1056 0.75 9.36 1.287 0.0900 0.76 9.38 1.295 0.0942 0.76 9.33 1.280 0.0946 0.76 9.34 1.276 0.0830 0.77 9.33 1.270 0.0970 0.76 9.31 1.293 0.0820 0.77 9.34 p K l pKw NH3-N NH3-N ( • o l a r U/ 6AHHA g a a i a ) ( u g / L ) 4.83 14.18 2.51E-05 427.2 4.83 14.14 3.87E-05 659.4 4.83 14.11 2.18E-05 371.9 4.83 14.18 1.86E-05 317.0 4.83 14.18 1.94E-05 331.1 4.83 14.16 2.06E-05 351.9 4.83 14.18 1.45E-05 247.1 4.84 14.21 1.89E-05 321.3 4.84 14.20 2.66E-05 453.7 4.84 14.21 3.16E-05 538.9 4.83 14.16 2.83E-05 482.6 4.83 14.18 2.69E-05 458.5 4.83 14.16 2.13E-05 362.5 4.83 14.14 2.48E-05 422.7 4.83 14.18 1.40E-05 239.2 08/20/87 3.78 0.1638 09/03/87 3.58 0.1556 09/17/87 3.50 0.2844 10/01/87 3.59 0.6644 10/15/87 3.65 0.4985 11/05/87 3.61 0.8565 11/19/87 3.60 0.2237 12/03/87 3.68 0.0159 12/22/87 3.63 0.0610 01/05/88 3.65 0.0246 01/20/88 4.22 0.0000 02/04/88 3.68 0.0389 02/23/88 3.68 0.0000 03/17/88 3.62 0.0000 04/07/88 3.68 0.0000 P2 PREMIER 0.2789 1.187 0.1026 0.2678 1.195 0.1016 0.4958 1.210 0.0991 1.1686 1.201 0.0989 0.8925 1.212 0.1035 1.5648 1.216 0.1026 0.4061 1.239 0.0901 0.0291 1.281 0.0727 0 . U 1 5 1.259 0.1056 0.0459 1.279 0.0778 0.0289 1.318 0.0780 0.1011 1.287 0.0873 0.2366 1.315 0.0641 0.0857 1.310 0.0821 0.0182 1.308 0.0599 0.75 9.31 4.83 0.75 9.28 4.83 0.75 9.25 4.82 0.75 9.28 4.83 0.75 9.28 4.83 0.75 9.28 4.83 0.76 9.30 4.83 0.78 9.38 4.84 0.75 9.39 4.84 0.77 9.31 4.83 0.77 9.34 4.83 0.76 9.34 4.83 0.79 9.36 4.84 0.77 9.34 4.83 0.80 9.41 4.84 14.14 2.94E-05 500.8 14.11 3.98E-05 678.8 14.07 2.71E-05 461.6 14.11 2.94E-05 501.1 14.11 2.50E-05 425.8 14.11 2.59E-05 440.6 14.12 1.70E-05 289.7 14.21 1.49E-05 254.6 14.23 2.24E-05 381.7 14.14 2.88E-05 490.6 14.18 2.31E-05 393.6 14.18 2.97E-05 506.9 14.20 1.94E-05 330.8 14.18 2.56E-05 436.1 14.25 7.5BE-06 129.1 1 MATSQUI PRECIP. STRIDE PRECIP. S B B B B B B i e e s s B BBSBBBBBEBBBSSBBE EBBS 08/05/87 15. 4 08/09/87 6 .4 08/25/87 15. 2 08/27/87 25 .8 09/08/87 11. 6 09/10/87 13 .2 09/22/87 12. 0 09/24/87 11 .8 10/06/87 3. 0 10/07/87 3 .6 10/20/87 0. 0 10/27/87 0 .0 11/10/87 30. 0 11/12/87 56 .0 11/24/87 99. 1 11/26/87 98 .6 12/08/87 96. 0 12/15/87 121 .8 12/29/87 116. 7 12/31/87 30 .2 01/12/88 23. 0 01/14/88 39 .6 01/26/88 69. 0 01/28/88 23 .4 02/09/88 76. 2 02/11/88 38 .1 03/01/88 51. 1 03/03/88 51 .8 03/29/88 121. 4 03/31/88 123 .4 EBBBBBB BEBBB = = B = BBB = E = = = EB = = = s e APPENDIX F . l . - P r e c i p i t a t i o n data ( RICHMOND PRECIP. PREMIER ST. PRECIP 08/14/87 25. .8 09/01/87 0. .0 09/15/87 22. .8 09/29/87 5. .6 10/13/87 0. .2 11/03/87 20. .2 11/17/87 74 . 4 12/01/87 61 . ,2 12/24/87 136. ,0 01/06/88 13. .6 01/19/88 44 . 2 02/02/88 23. .3 02/24/88 67 . ,0 03/15/88 51 . 8 04/05/88 118. .2 08/20/87 15.2 09/03/87 11.4 09/17/87 11.1 10/01/87 5.6 10/15/87 1.2 11/05/87 36.2 11/19/87 92.6 12/03/87 123.8 12/22/87 114.8 01/05/88 10.6 01/20/88 101.8 02/04/88 33.9 02/23/88 110.7 03/17/88 73.4 04/07/88 222.9 m i l l i m e t e r s ) used i n S t a t i s t i c a l a n a l y s i s 253 MATSQUI ALL N = : 49 VARIABLE MEAN STO. OIV. K -S z STAT. 2 TAILED PROB . PRECIP 58. . 33 40. 8 1 1. 151 0 .14 1 W.L . 7 , 43 2.21 1 .977 0 .001 TW 13. 61 3. 15 1.014 0 .256 TG 14 . 02 4.80 1 . 369 0 .04 7 PH 6.4575 0.7086 0.871 0 .434 NH3-N LEACH 648. 88 827.00 2. 308 0 .000 NH3-N GAS 197 . 33 236.06 1 . 747 0 .004 FLOW 43. 16 35.00 0. 762 0 .608 PRESSURE 101 . 80 0.578 1 .046 0 .224 X CH4 35. 76 13.71 1.247 0 .089 CH4 FLUX 3. 10 2.96 1.215 0 . 105 C02 FLUX 7 . 03 5.77 0. 782 0 . 574 IONIC ST. 0. 10 0. 12 2.191 0 .000 STRIDE AVE. ALL N = 44 VARIABLE MEAN STD. DIV. K -S 2 STAT. 2 TAILED PROB.. PRECIP 43. 74 40.09 1. 328 0. .059 W.L. 10. 80 4 . 98 2. 322 0. 000 TW 12. 65 1.09 1.94 1 0. 001 TG 14 . 36 3.69 1.437 0. 032 PH 6. 18 0.22 1 . 746 0. 005 NH3-N LEACH 7. 83 6.56 1.271 0. 079 NH3-N GAS 243. 04 140. 7 1.131 0. 155 FLOW 5. 54 8.13 1 .810 0. 003 PRESSURE 101 . 74 0.59 0.906 0. 384 I CH4 46. 75 15.81 1. 365 0. 048 CH4 FLUX 0. 56 0.86 1.899 0. 001 C02 FLUX 0. 58 0.97 1.94 0. 001 IONIC ST. 0. 02 0.01 ===== ===== :== 0. 703 0. 707 RICHMOND ALL N B6 VARIABLE MEAN STD. DIV. K -S z STAT. 2 TAILED PROB. PRECIP 42. 31 40. 14 2.020 0. 001 W.L. 3. 33 0.89 0.791 0. 558 TW 20. 87 4.34 1.209 0. 108 TG 19. 51 6.76 1.074 0. 199 PH 6 . 39 0. 34 0.533 0. 939 NH3-N LEACH 117. 03 128. 3 1.979 0. 001 NH3-N GAS 143. 17 155.34 1.654 0. 008 FLOW 55. 22 $7.09 2.246 0. 000 PRESSURE 102. 09 0.45 1.505 0. 022 X CH4 47 . 96 11.94 2. 303 0. 000 CH4 FLUX 5. 37 6.71 2. 169 0. 000 C02 FLUX 11. 43 14.05 2. 180 0. 000 IONIC ST. 0. 05 0.03 1. 140 0. 149 PREMIER ST. ALL N = 30 VARIABLE MEAN STD. O I V . K •S z STAT. 2 TAILEO PROB. PRECIP 64 . 35 62.01 1.141 0. 148 W.L. 12. 22 1.59 1.217 0. 103 TW 22. 42 1 . 18 0.937 0. 344 TG 16. 23 4 .04 0.839 0. 482 PH 6. 64 0. 10 0.485 0. 973 NH3-N LEACH 225 ,. 7 33.54 0.826 0. 503 NH3-N GAS 169 . 4 101.0 0.716 0. 685 FLOW 2. 43 1 .67 1 . 104 0. 174 PRESSURE 102. 15 0.54 0.595 0. 871 X CH4 22 1.2 20. 3 0. 750 0. 627 CH4 FLUX 0.1320 0.2034 1.413 0. 037 C02 FLUX 0.2601 0.3572 1 . 331 0. 058 IONIC ST . 0 0926 0.0127 0.918 0 .0368 APPENDIX F . 2 . -R e s u l t s of K o l a o g o r o v -Sm i r o v Goodness Of F i t Test 254 APPENDIX F.3 - MATRIX RESULTS OF PEARSON PRODUCT-MOMENT CORRELATIONS ^ n IUTSSUI VARIABLES ppt. 8.L. Tw tg pH NH3-N NH3-N FLOW PRESS. I CH4 CH4 FLUX C02 FLUX IONIC ST. Leach VI V2 V3 V4 V5 V6 V7 V8 V9 V10 V l l V12 V13 VI X , , -0.7618 , , -0.5791 X X X X X , n I I I X I I X I X I X X X V3 X I X X I I X I I I I X X V4 -0.7618 I I X I I 0.7672 0.5878 X X 0.6933 0.6236 I V5 1 I X X X X 0.6439 I X X X I I V6 I I I X I X X 1 X I I I I V7 -0.5791 X X 0.7672 I I I 0.6439 I I 0.7944 0.6763 X V8 X I X 0.5878 1 X I I X I 0.9637 0.9444 X V9 X X X X I X X X X X X I X V10 X I X I I 1 I X X I X I I V l l X X I 0.6933 X I 0.7944 0.9637 I I I 0.9700 X V12 X I I 0.6236 I I 0.6763 0.9944 I I 0.9700 X I V13 X * 1 X 1 X I 1 1 X X 1 F2 KATS8UI VI X X --0.6265 X -0.6602 . . . . - - - - - . . . . -0.5741 V2 X I X X X I X 0.6341 X -0.5886 I x X V3 X I X. 0.6277 I 0.6826 0.7105 X X X X I 0.6559 V4 -0.6265 X 0.6277 X X 0.7387 0.8925 I X I X I 0.69S9 V5 X X X I I 0.7757 X I I X 1 x -0.7375 V6 X X 0.6826 0.7387 0.7757 I I I X X X X 0.9123 V7 -0.6602 I 0.7105 0.8925 X 0.5605 X X I I X X 0.6026 V8 X 0.6341 I X I X X X X I 0.8497 0.9712 I V9 X X X X I I I X X I 1 X X V10 I -0.5886 I I X I X X X X I I X V l l X I I X X I X 0.8497 I I X 0.9258 X V12 I I I X I I I 0.9712 X I 0.9258 I I V13 -0.5741 X 0.6559 0.6962 0.7375 0.9123 0.6026 * 1 . _ . ! . _ . . X F3 KATSOW VI --0.7325 . . . . . . . . . . . . . . . . . . . . . . - = - -—. i . . . . -V2 X I I I I I X i I . I i i I V3 X I I X I X X i X I i i I V4 -0.7325 I I X I X 0.6834 i I 0.6047 0.6112 i I V5 X I X X I I I i I I I i I VS X I I X I I I i I I I i I V7 -0.6275 X I 0.6B34 X x I t I X I X X V8 X I I X I I I i X I 0.9524 0.9828 X V9 I I I I I I X X I I I I I V10 X X I 0.6047 I X X I X I 0.7097 I I V l l X I I 0.6112 X X X 0.9524 I 0.7097 I 0.9551 I V12 X I I 0.5727 I X X 0.9828 I I 0.9551 X I V13 X X X X X I X X 1 X X X I ========= 1======== ========= ======== ========== ======= .========== ========= ======== ================= ========== ======== ========= 255 APPENDIX F.3 F4 flATSQUI =========- ================ ========= == = = = = = = = = = == = = =========== =========: ======== ========= :========= ================== VARIABLES ppt. W.L. Tu pH NH3-K NH3-N FLOU PRESS. 1 CH4 CH4 FLUX C02 FLUX IONIC ST. Leach 6 K VI V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l V12 V13 VI I I I -0.7669 I I -0.6714 r -0.6268 I -0.6377 -0.5940 X V2 I I I I 1 X I i I X X X X V3 I ' I I X I I I i I I X X X V4 -0.7469 I I I I I 0.2503 i I 0.7034 0.690S 0.6087 X V5 I I I I I I I i X X X X X % I I I I I X I i X I X I I V7 -0.6714 I I 0.7503 1 X I 0.6149 1 I 0.6049 0.5998 X V8 I I I I I X 0.6149 I I X 0.9613 0.9905 X V9 -0.6268 I I I I I I I I X X I X VIO I I I 0.7034 I I I I X I I I X VII -0.6377 I I 0.6908 i I 0.6049 0.9613 I X X 0.9700 X V12 -0.5940 I I 0.6087 I I 0.5998 0.9905 I X 0.9700 I X V13 I I I I I X X I I X I I X F5 NATSQUI VARIABLES ppt. y . L . Tu pH NH3-N NH3-N FLOU PRESS. I CH4 CH4 FLUX C02 FLUX IONIC ST. Ltach & s VI V2 V3 V4 V5 V6 V7 VB V9 VIO V l l VI2 V13 VI X I -0.7720 -0.8416 -0.6988 -0.6955 I \"7 -0.7707 ===-_=__ X X -0.6762 V2 I I I X I I I x I X I I I V3 -0.7720 I X 0.9167 X X X X 0.6297 I X X 0.6427 V4 -0.8416 I 0.9167 I I 0.6456 I I X X X X 0.6768 V5 -0.6988 X X I X 0.7459 I X X X I I 0.7929 V6 -0.6755 X X 0.6456 0.7459 X X X X X I X 0.9782 V7 X I X X I I X X X X X I I V8 I I X X I X I X X I 0.9840 0.9905 X V9 -0.7707 X -0.6297 I I I X X I I X I X VIO I I I I I X I X X I I X X VII I I X X I I X 0.9540 X I X 0.9882 X V12 I I X X X X I 0.9905 0.5581 I 0.9882 I X V13 -0.6762 I 0.6427 0.6768 0.7929 0.9782 X I X X X I X :=============== =========== ========= ========= ========= ======= 3 = = = = = = = = = ========== ======= ========== ========= ========= 256 VARIABLES pp V I V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l VI2 V13 251 Tv V3 0.6558 0.6730 APPENDIX F.3 F2 STRIDE pH NH3-M NH3-N Leach Gas V5 V6 V7 -0. 377 251 0.6558 464 0.6550 X I X 0.6477 I X I X X X X I I FLOW PRESS. V8 V9 943 960 H4 CH4 0 v: LUI C02 FLUX IONIC ST. 0.9943 0.9909 X V12 I X X X I X X 0.9960 I I 0.9909 X I V13 X X 0.6730 I 0.7464 0.6S50 X X X X X I I F3 STRIDE VI V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l V12 V13 -0.6101 -0.6022 0.8627 101 -0.6022 0.8627 519 0.5867 171 519 X I X 1 X I X X I X 0.9579 0.9624 0.6424 -0. 171 1867 9879 0 710 ,617 I X X X X X I 9624 X I .9710 X 6554 X I X X X X X 0.6424 X I 0.6617 0.6554 I 257 APPENDIX F.3 VARIABLES pp V VI V2 V3 V4 V5 VS V7 V8 V9 VIO V l l V12 V13 U . L . V2 0.6280 -0 983 pH V5 X I X X I X I -0.6505 X I X -0.6367 0.6156 F7 STMOE NH3-N L M C B V6 NH3-N V7 F8 S FLOW PRI va i x X X -0.6505 X X I X X 0.985B 0.9921 -0.7215 SS. H4 CH4 FLUI C02 FLUX IONIC ST. V l l -0.9858 V12 X X X I -0.6367 X X 0.9921 X I 0.9738 X -0.7442 V13 X X 0.6280 -0.5983 0.6156 1 X -0.7215 X X -0.6731 0.7442 X RIDE VI I X X X I I I X I I X I I V2 X I I X X I I : x I I X X V3 X X X X I I I I X I I I I V4 I X I X X I 0.8442 I X I I X X V5 X X I I I I j : i I I I I V6 I I I I I I I X I I I I V7 X I I 0.8442 I X X X I I I X I V8 I I I X X X I I 1 I 0.9236 I I V9 X I I I X J I I X I I X X VIO I X X I I I X 1 X I X I I V l l X I I I 1 I 1 0 . 3457 X X 0.9128 I I V12 X X I I I X I 0. 9236 I I I I X V13 I I I I I I I I I I I X X 258 APPENDIX F.3 Be RICHKOK) VARIABLES ppt. H.L. V! V2 VI V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l V12 X I 0.5625 I X X Tw V3 X V4 pH V5 NH3-N L « « h V6 NH3-N V7 X X 0.8766 0.7210 0.8434 X -0.6083 -0.6672 X 0.8766 0.7210 0.6107 0.6965 I 0.8434 0.7568 0.B186 X -0.6083 0.6107 0.7568 0.5781 I 0.9278 I -0.6672 0.6965 X I 0.8186 I I -0.7031 0.7056 0.9278 X I I 0.6989 I X I -0.7195 X X -0.7263 0.5624 I -0.6985 X I -0.6971 X I -0.7133 -0.7156 -0.7304 I FLOW PRE! V8 X -0.7031 0.5781 0.7056 0.5418 I V13 -0.6002 0.7355 -0.7002 0.7264 0.9054 0.9775 I -0.6971 -0.7198 X X I I 0.9914 0.9934 -0.7653 S. X CH4 CH4 FLUX C02 FLUX IONIC ST. VIO I X I 0.6989 I X X I X X X I I V l l I X -0.6985 X -0.7133 -0.7263 X 0.9914 X X X 0.9993 -0.7799 V12 X -0.7102 I -0.7156 X -0.7304 X 0.9934 I 0.9993 X -0.7817 V13 -0.6002 0.7355 0.8628 0.7264 0.9054 0.9775 X -0.7653 I I -0.7799 -0.7817 I D9 R1CHH0XD VI , X -0.5559 I I I X 1 I -0.5882 V2 I I 0.8957 0.7899 I X I I I 1 I I X V3 I 0.8957 I 0.7179 X 5 I I I 1 I X I V4 I 0.7899 0.7179 I X X I -0.6548 X 1 -0.6451 -0.6024 I V5 -0.6559 X I I X 0.7823 I X I 1 X I 0.7696 V6 I I I I 0.7823 I X I 0.6075 X X 0.9723 V7 I X I I X X I X I 1 I I X V8 I I X X X I I I I 0.9718 0.9667 X V9 I X I I X 0.6075 I X I 1 I I X VIO I I I X X X 1 X X 1 I I X V l l I I X X X X X 0.9718 I X 0.9919 X V12 I I I I I X I 0.9667 X 0.9919 I I V13 -0.5882 1 1 1 0.7696 0.9723 I X I I X C6 RICHnTHS VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I X ' \" ] i . . . . = \" \" \" \" X V2 I X I X I I I I I I X I V3 X X I 0.8833 X I 0.5767 X I I I 0.7276 V4 I X 0.8833 I I X X X I X x 0.6454 V5 I X I I X 0.6B50 I X X X I I V6 I I X I 0.6850 X I I X X I 0.6544 V7 I I 0.5767 I X X X I X X I X V8 I I I X 1 I I X x 0.9918 0.9943 I V9 I X I I X I I I I X X X VIO I I I X X X I I X X X I V l l I I I I I I I 0.991B I X 0.9991 I V12 I I I X I I X 0.9943 X 0.9991 I I V13 I I 0.7276 0.6454 X 0.6544 I X I I I I ======== ========== ========= ========= ========= ========-•================ ====================== ============== ========= ========= 259 APPENDIX F.3 67 RICHMOND VARIABLES ppt. VI VI V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l V12 V13 I I -0.7703 -0.7256 I I X I i -0.5881 I I ( U .L . V2 I I I I 0.6282 0.7449 I I I I I I 0.6761 Tv V3 19 V4 -0.7703 -0.7256 I I 0.7404 0.7364 0.7294 I I I 0.7335 I I I X 0.7404 I 0.8025 0.6595 0.7600 I I I I I 0.8196 pH V5 I 0.6282 0.7364 0.8025 I 0.8216 X I I I I I 0.9444 KH3-H NH3-N FLOM PRE! I n c h 6 J S V6 V7 VB 0.7449 0.7294 0.6595 0.8216 I X X I X X X 0.9079 I X I 0.7600 X I X I I I I I I 0.9930 1947 X CH4 CH4 FLUX CQ2 FLUX IONIC ST VIO -0.5881 X 0.7335 I I X I I -X 1 X X X V l l I X X X I X X 0.9930 X X X 0.9984 X 0.9947 0.99B4 V13 X 0.6761 0.7985 0.81% 0.9444 0.9079 X X X X X X X D.55 RICHMOND VI V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l V12 V13 I I 0.7862 X X X X X I I 0.8381 X -0.7509 0.8381 0.6430 I -0.7509 0.6430 0.7528 .7288 .7250 X I I I I I I X 0.6271 X I I X I I X I I 0.6352 X I I I X X -0.7862 X 0.7528 0.72BB 0.7250 0.6271 0.6354 X I X X X X X -0.6996 0.6264 0.8275 0.6729 0.7051 0.9170 993 0.9981 0.9991 X 991 -0.6996 0.6264 0.8275 0.6729 0.7051 0.9170 X X X X X X X VI V2 V3 V4 V5 V6 V7 V8 V9 VIO V l l V12 V13 X I I 0.7721 0.6423 0.7974 I 0.7204 I 0.9473 0.7978 0.7289 0.86B8 I X 0.7271 X 0.6199 0.83S3 X 0.8557 I 0.7534 0.8818 0.8244 0.8243 I X I 0.6199 X 0.8306 I 0.8304 I 0.6387 0.8173 0.8292 0.7604 B.53 RICHMOND I X 0.7974 0.8353 0.8306 X X 0.8966 X 0.8229 0.9196 0.8927 0.9589 X I 0.7204 0.8357 0.8304 0.8966 I I X 0.7191 0.9897 0.9937 0.8466 I I 0.9473 0.7534 0.6587 0.8229 I 0.7191 I I 0.7925 0.7133 0.9122 I X 0.7978 0.8818 0.8173 0.9196 I 0.9897 X 0.7925 0.9835 0.8917 X X X 0.7289 0.8244 0.8292 0.8927 I 0.9937 X 0.7133 0.9835 I 0.8356 I X 0.8685 0.8243 0.7604 0.9589 X 0.8466 X 0.9122 0.8917 0.8356 I 260 APPENDIX F.3 PI PRXHIH ===== ======= ========= ========= =========== ===== ========== .======= ========= ==== ===== ======== ========= ========= ========= •.RUBLES ppt. U .L . T* T| pH NN3-N NH3-N FLOH PRE ;s. X CH4 CH4 FLUX C02 FLUX IONIC ST. I n c h 6 « VI V2 V3 V4 V5 V6 V7 V8 V< VIO V l l V12 V13 :======: ====== ========= ========= =========== ===== =======::=. ====== ======== ==== .=== ========. ========= ======== ========= VI I 1 I -0.6810 I -0.5734 I I -0.6108 X X -0.6612 V2 I I I X I X I X - o . : 994 X 0.5740 0.5468 I V3 I X I X I 0.6296 0.7086. I X X X 0.6162 V4 -0.6810 X I X I I I I 0.6521 X X X V5 I I I X X X I x X I X X V6 -0.5754 X 0.6296 X x X I I X I X I V7 X I 0.7086 X I X X I I X I X V8 I X I X I I I x I 0.6941 0.6979 X V9 X -0.5994 X X X X x X I I X X VIO -0.6108 I I 0.6521 I I I I I 0.7794 X 0.7452 V l l X 0.5740 I X I X I 0.6941 0.7794 X 0.9939 I V12 X 0.5968 0.5968 X I X I 0.6979 0.7406 0.9939 I X V13 -0.6612 X X 0.6102 1 I 1 0.7452 I I X P2 PREMIER : s s = = = £ :======== ========= ========= =========== ===== =========== ====== ======== ===== ==== ======== ======== ========= ========= VI I -0.5622 -0.8416 -0.6922 I -0.8211 x X -0.6737 X X -0.7026 V2 -0.5622 I 0.6960 0.6565 X I I 0.6192 0.8153 0.7925 0.7512 0.7861 V3 -0.8416 0.6960 X 0.9250 X 0.7984 I X 0.7900 0.6669 0.6410 0.6445 V4 -0.6922 0.6565 0.9250 I X 0.6528 X X 0.8578 0.7055 0.6818 0.5866 V5 X X I I I I i X X X I X V6 -0.8211 I 0.6528 0.6528 I X i I 0.6012 X X 0.7667 V7 X X I I X I i I X I X X V8 I 0.6192 X X I I i X X 0.9204 0.9519 X V9 X I X X I X X X I X X X VIO -0.6737 0.8153 0.8578 0.8578 X 0.6012 I I 0.7367 0.7367 I 0.8368 V l l X 0.7925 0.7055 0.7055 I X I 0.9204 I X 0.9913 0.6096 V12 X 0.7511 0.6818 0.6818 I X X 0.9519 0.9913 0.9913 I 0.5539 V13 -0.7026 0.7861 0.5866 0.5866 X 0.7667 I X 0.6096 0.6096 I X --------- ======= ========= ========= ========== ===== =========== ======= ======== ===== ==== ========= ========= ========= "@en ; edm:hasType "Thesis/Dissertation"@en ; edm:isShownAt "10.14288/1.0062503"@en ; dcterms:language "eng"@en ; ns0:degreeDiscipline "Civil Engineering"@en ; edm:provider "Vancouver : University of British Columbia Library"@en ; dcterms:publisher "University of British Columbia"@en ; dcterms:rights "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en ; ns0:scholarLevel "Graduate"@en ; dcterms:title "Ammonia gas dynamics in four Vancouver area landfills"@en ; dcterms:type "Text"@en ; ns0:identifierURI "http://hdl.handle.net/2429/28506"@en .