landfill gas generatian anlc-bnc.ca/obj/s4/f2/dsk3/ftp04/mq39150.pdfaverage interna1 temperature of...
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Landfill Gas Generatian A t A
Semi-Arid Landfill
A T H E S I S
SUBMITTED TO THE FACULTY OF GRADUATE STUDLES AND RESEARCH
I N PARTIAL FULFILLMENT O F THE REQUIREMNTS
FOR THE DEGREE OF
MASTER OF A P P L I E D SCIENCE
IN ENVIRONMENTAL SYSTEMS E N G I N E E R I N G
FACULTY OF E N G I N E E R I N G
UNIVERSITY OF REGINA
Douglas A. Opseth
Reg ina , S a s k a t c h e w a n
December, 1998
O Copyr igh t 1 9 9 8 : Douglas A. Opseth
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This research was undertaken in order to characterize gas
emissions fxom semi-arid landfills in Saskatchewan. The
Saskatoon Landfill and the Regina Fleet Street Landfill were
examined for greenhouse gas emissions and spatial emission
variability.
Waste sampling was also conducted at the Regina Fleet Street
Landfill in order to help explain the emission results. The
key findings were an average moisture content of 22%, and an
average interna1 temperature of 1 7 . 3 " ~ . Both of these levels
are significantly below what is deemed optimal for landfill
gas generation.
In addition to waste sampling, shallow gas wells were
installed at both sites to allow for trace gas analysis. The
results of the trace gas anaiysis indicated high spatial
variability at both sites. A range of volatile organic
carbons (VOCs) were detected in the samples. When compared
to landfills in Ontario, the two Saskatchewan landfills
showed low to medium levels of VOCs, with the exception of
freons. Gas samples from both Saskatchewan landfills had
benzene and vinyl chloride concentrations exceeding the
limit set by the Occupational Health and Safety A c t .
iii
Two methods were used, a flux chamber system and a flame
ionization detectox, to examine methane and carbon dioxide
ernissions. The flame ionization detector proved useful for
preliminary analysis of the site, while the flux chamber was
very useful for detailed analysis of emission rates. The
emission rates were estimated as 8842 tonne/year of methane
and 34,353 tonne/year of carbon dioxide at the Regina Fleet
Street Landfill, and 3176 tonne/year of methane and 15,146
tonne/year of carbon dioxide at the Saskatoon Landfill. A
U.S. EPA landfill gas model was used to estimate gas
generation at the Regina Fleet Street Landfill. The field
results were on the higher end of the range suggested by the
model. At both landfills, the ernissions showed high spatial
variability and were concentrated along the d o p e s .
The ernissions rates, 4.65 m3/tonne/year for the Regina Fleet
Street Landfill and 6.6 rn'/t~nne/~ear for the Saskatoon
Landfill, are in the low to medium range of landfill gas
emission rates reported for landfills in North America.
Acknowledgements
1 would like to take this opportunity to express my sincere
thanks and appreciation to rny thesis advisor, Dr. Kim
B a r l i s h e n . Without her time and guidance this project could
n e v e r have been completed. 1 would also l i k e to thank Dr.
Fuller for agreeing to be rny thesis CO-supervisor. 1 would
l i k e t o thank Mr. Gary Nieminen, Mr. Derrick Bellows and Mr.
Tom Bokinac al1 from the City of Regina, who provided
valuable assistance and information required f o r the
completion of this project.
1 would like to t h a n k Roopa Nair for her understanding and
constant encouragement in the completion of this research. 1
would also like to thank my mother, Mary Opseth, and sister,
Megan Opseth, for their support and encouragement throughout
this project. 1 would like to o f f e r special thanks to my
father, Art Opseth, for bis enormous help in the preparation
and editing of this document.
T a b l e of Contents
Abstract .................................................. ii .......................................... Acknowledgements iv
.......................................... L i s t of Tables v i i i
.......................................... List of Figures ..x
.......................................... 1.0 Introduction 1
2 . 0 Background Information on Landfill Gas Generataon ..... 8 2.1 Mechanisms of Landfill Gas Generation ......... ,..8 2.2 Factors Affecting Landfill Gas Generation. ...... 12 2.3 Factors Affecting Landfill Gas Emission ......... 16
3.0 Design Considerations for a Landfill Gas Study ....... 20
3.1 Landfill Gas Field Investigations ............... 20 3.1.1 Monitoring Locations ................. -21 3.1.2 Monitoring Frequency ................. 2 4
3.1.3 Landfill Parameters to Monitor ........ 26 3.1.4 Methods. .............................. 27
3.2 Modeling of Landfill Gas Generation ........... .,34 4.0 Metbodology .......................................... 40
4.1 Regina Fleet Street Landfill G r i d System ........ 4 1
4.2 Preliminary Landfill Gas Investigation .......... 42 4.3 Detailed Landfill Gas Investigation. .........O. *44
4.4 Shallow Gas Wells ............................... SI 4.5 Waste Sample Extraction ......................... 54 4.6 Modeling ........................................ 56
............................... 4.7 Supplemental Data 59
.................................... 5 . 0 F i e l d S t u d y Sites 6 1
................ 5.1 The Regina F l e e t Street Landfill 6 1
.......................... 5.2 The Saskatoon Landfill 67
6 . 0 Results of the Landfil1 Investigations .............. - 7 0
..... 6.1 Regina Fleet Street Landfill Waste Sampling 70
6.2 Regina Fleet Street Landf il1 Preliminary
Landfill Gas Study .............................. 7 3
6.3 Saskatoon Landfill and Regina Fleet Street
.................. Landfill Shallow Gas Well Data 75
6 . 4 Regina Fleet Street L a n d f i l l Gas
................................ Modeling Results 79
6.5 Saskatoon Landfill and Regina Fleet Street
L a n d f i l l Detailed Gas Study .................... -83 7.0 Discussion of L a n d f i l l Investigation R e s u l t s ......... 9 1
.................... 7.1 I n t e r n a 1 L a n d f i l l Conditions 9 1
7.2 Combustible Vapour Concentrations ............... 94 .............................. 7.3 VOC Concentrations 97
7.4 Estimated Landfill Gas Generation Rate ........ 100 7.5 Spatial Variability ............................ 102
7.5.1 The Saskatoon Landfill ............... 102
7.5.2 The Regina E l e e t Street Landfill ... ..l04 7.6 Emission Rate .................................. 108 7.7 Landfill Gas Control Considerations ............ I l 0
8.0 Summary, Conclusions and Recommendations... ......... 113
vii
8 . 1 Summary a n d Conclusions ....S................... 113
8 . 2 R e c o m e n d a t i o n s ................................ 1 2 0
References. .............................................. 122 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography -130
Appendices
Appendix A - Reg ina F l e e t Street L a n d f i l l FID Results.
Appendix B -Regina F l e e t Street L a n d f i l l VOC Results.
Appendix C - Envi ronment Canada k & Lo Values for the LAEEM-
Appendix D - Saskatoon L a n d f i l l Gas E m i s s i o n s .
Appendix E -Regina F l e e t S t r e e t L a n d f i l l Detailed G a s
Results.
v i i i
L i s t of Tables
Table 2.1 - Percentages of various landfill gas
components ..-.........e.-.e............-....ll
Table 5.1 - Types and quantities of waste accepted
.......... at the Regina Fleet Street Landfill 66
Table 6.1 - Data from the basic laboratory analysis
f o r Borehole#l. .........-..m................. 71
Table 6.2 - Detailed laboratory analysis for select samples from Borehole#l ...,...... ..-..72
.................. Table 6.3 - Temperatures from Borehole#2 72
Table 6.4 - Data from basic laboratory analysis for the Test Pit .,...,........................-. .73
Table 6.5 - VOC concentrations (pg/m3) from shallow gas
w e l l s at the Regina Fleet S t r e e t Landfill .... 76 T a b l e 6.6 - VOC concentrations (pq/m3) from four landfill
wells at the Saskatoon Landfill ........... -77
Table 6.7 - Summary of VOC concentration data from the Regina F l e e t Street Landfill ...........-.... -78
Table 6.8 - Summary of VOC concentration data from the
Saskatoon L a n d f i l l ..-...........-.O.........- 78
Table 6.9 - Amounts of waste landfilled from 1981 to
1997 ............1...-..--...0.........--.-...80
Table 6.10 - Parameters and assumptions used in landfill gas simulations .............-..........-..... 82
............. Table 6.11 - Results of landfill gas modeling 83
... Table 6.12 - Data from the Saskatoon Landfill Gas Study 84
Table 6.13 - Emission rates from the Saskatoon L a n d f i l l
.................................... Gas Study 3 4
Table 6.14 - Data from the Regina F l e e t Stree t
Landfill Gas Study ........................... 87 Table 6.15 - Emission rates from t h e Regina Fleet
Street Landfill Gas Study .................... 90
L i s t of Figures
F i g u r e 2 . 1 - Major steps i n the convers ion of o r g a n i c
...................... matter t o l a n d f i l l gas -9
F i g u r e 2 . 2 - L a n d f i l l gas generation c u r v e s ..........,....Hl
.... F i g u r e 2 . 3 - F a c t o r s a f f e c t i n g landfill g a s g e n e r a t i o n 12
................ F i g u r e 3.1 - A s h a l l o w g a s c o l l e c t i o n well 31
....................... F i g u r e 4 . 1 - Flux chamber a p p a r a t u s 50
F i g u r e 4.2 - Waste sampl ing and s h a l l o w gas w e l l
l o c a t i o n s ......................o..,.......... 53
F i g u r e 5 . 1 - Waste ages a t t h e Regina F l e e t Street
.................................... L a n d f i l l 6 4
........... F i g u r e 5 . 2 - The Saskatoon L a n d f i l l s t u d y area. 68
............. F i g u r e 6 . 1 - P r e l i m i n a r y l a n d f i l l g a s r e s u l t s 74
F i g u r e 6 . 2 - Methane e m i s s i o n s ( ~ / h o u r / m ~ ) at t h e
Saskatoon Landfill . . - . , , o . . - . . . . . . . . . . . . , . . . . 85
Figure 6 . 3 - Carbon d i o x i d e emissions (~/hour / rn ' ) a t
t h e Saskatoon L a n d f i l l , , . . ....o.........-.... 86
F i g u r e 6 . 4 - Methane e m i s s i o n s a t t h e Regina F l e e t
S t r e e t L a n d f i l l . . . . - . . . . . . . . . . . . . . . . . . . . 8 8
F i g u r e 6 . 5 - Carbon d i o x i d e e m i s s i o n s a t t h e Regina
F l e e t Street L a n d f i l l .-..........C....-.LL..*89
F i g u r e 7 . 1 - Variablity in FID r e a d i n g s ..............-.... 96
Figure 7 . 2 - Combustible vapour f rom t h e h i g h e s t
c o n c e n t r a t i o n p o i n t s - .......--.........--... -96
1.0 Introduction
In Canada, approximately 90% of the estimated 18 million
tonnes of municipal solid w a s t e d i s p o s e d of each year is
landfilled (Hickling, 1994). Once this waste has been
landfilled, it will begin to biodegrade and produce landfill
gas. The gas generated by the breakdown of the w a s t e in a
landfill is composed of two main components, methane and
carbon dioxide, as well as numerous trace gases.
There is increasing interest in landfill gas generation
because landfill gas can have both beneficiaf and harmful
e f f e c t s . Some of the harmful effects of landfill gas arise
from the fact that it can migrate away from a landfill site
and accumulate in surrounding buildings. When landfill gas,
particularly hydrogen sulfide gas, is present, in
concentrations as low as 0.005 ppm, its offensive odor can
lead to cornplaints from affected r e s i d e n t s (Environment
Canada, 1995). A more serious concern with regards to
methane gas is that it can be explosive. The lower explosive
limit (LEL) for methane gas i s 5% b y volume of air
(Hickling, 1994). Landfill gas, whether it remains at the
landfill site or migrates to neighboring areas, m u s t be
viewed as a potential hazard and nuisance, and dealt with
accordingly.
Certain trace gases presen t i n l a n d f i l l gas can be extremely
dangerous (Young and Parker , 1983; Brosseau and Heitz,
1994) . The most important of t h e trace gases are a group
termed v o l a t i l e o rgan ic compounds (VOCs). These compounds
can evaporate very e a s i l y and c a n be active i n nurnerous
chernical r e a c t i o n s (Great B r i t a i n , 1992a). Two of the most
important VOCs a r e benzene and v i n y l c h l o r i d e ; both of these
gases are known t o be carc inogenic (Walsh e t a l . , 1988;
Brosseau and H e i t z , 1994 ) .
L a n d f i l l gas i s a l s o a c o n t r i b ~ t o r t o the greenhouse e f f e c t .
I t is b e l i e v e d t h a t g l o b a l warming i s p a r t i a l l y caused by
t h e accumulation of var ious greenhouse gases of which
methane and carbon d iox ide a r e two of t h e most s i g n i f i c a n t
( U S . EPA, 1 9 9 7 a f . Because of t h e p o t e n t i a l environmental
problems posed by t h e greenhouse effect, Canada, a long wi th
a l a r g e nurnber of other c o u n t r i e s , have signed agreements t o
s t a b i l i z e o r reduce greenhouse gas emiss ions relative t o
1990 levels b y t h e year 2000. The overall r e l e a s e of carbon
d i o x i d e from landfills is r e l a t i v e l y i n s i g n i f i c a n t compared
t o t h e amount of anthropogenic carbon d iox ide from o t h e r
sources, such as t h e energy i n d u s t r y (Environment Canada,
1997a). On t h e o t h e r hand, methane f r o m l a n d f i l l s may be a
major c o n t r i b u t o r t o t h e greenhouse e f f e c t - I n Canada,
landfills account for from 23 to almost 40% of al1
anthropogenic methane emissions (Hickling, 1994; Environment
Canada, 1997a). Canadian methane emissions, from al1
sources, have increased by 16% in the period from 1990 to
1995 (Environment Canada, 1997a) . This is very important b e c a u s e methane is approxirnately 25 times as powerful a
greenhouse gas as carbon dioxide due to its chemical
interactions in the atmosphere (Conestoga-Rovers &
Associates Limited, 199533). Atmospheric methane is believed
to be responsible for approximately 20% of the global
warming ef fec t (Great Britain, 1992a) .
Landfill gas in the soi1 interferes with a plant's root
system, by depriving it of oxygen (Emcon Associates, 1980).
This is of particular importance because most landfills,
upon closure, become parks or recreational areas. The
destruction of surface vegetation can also lead to surface
erosion and damage to the integrity of the landfill cover.
This in turn can lead to infiltration of moisture, which can
promote landfill gas and leachate generation.
There are several benefits that arise from the production of
landfill gas. The energy potential of methane gas makes it a
valuable resource, which can be extracted and used as fuel
for power generation, either on site or off site. Another
benefit of landfill gas is that its production leads to a
decrease in the strength of leachate, which can lower the
risk of groundwater contamination due to leachate
infiltration (Senior, 1990). A third benefit of landfill gas
generation is that the decomposition of waste that produces
gas also leads to the settling of a landfill site. The
quicker a landfill settles, the sooner it can be used for
post closure purposes.
Little research has been undertaken to study landfill gas
generation in semi-arid landfills, such as those found in
Saskatchewan, Alberta and Manitoba. A number of studies have
been conducted in the United States to determine landfill
gas emissions at larger landfills, p r i r n a r i l y in California
and New York (Bariaz et al., 1990; Pohland and Harper, 1987;
McBean et al., 1995). The majority of these studies have
examined large landfills in areas witn climates
significantly different to that on the prairies. These
studies have tended to rely on landfill gas models and
landfill gas extraction wells or laboratory simulations in
order to estimate landfill gas generation. In addition, the
purpose of many of these studies has been to determine
control and utilization possibilities, not to determine
actual quantities and composition of landfill gas.
In Canada, a number of investigations have been conducted to
determine landfill gas emissions. These studies have
occurred in provinces with specific landfill gas emissions
legislation, primarily Ontario (Williams and Williams, 1995)
and British Columbia. However since the climate in these
locations di f fers from that on the pra ir ie s , the results
from these studies may not be applicable to semi-arid
landfills. In addition, these studies have not exarnined
interna1 landfill conditions. These studies do, however,
prov ide a starting point for designing a landfill gas study
at a semi-arid landfill.
The .City of Calgary has undertaken a preliminary study to
determine if dangerous levels of landfill gas are present,
primarily in surrounding buildings. This study involved
measuring the concentration of methane at a few points at
and around the landfill. Because only low levels of methane
were found, the study was discontinued. The City of Edmonton
monitors landfill gas collected in landfill gas wells in
orde r to properly control that gas. However, they have n o t
undertaken a study to determine total q u a n t i t i e s of landfill
gas being generated nor have they looked at factors within
the landfill which might affect gas generation.
In the fa11 of 1996, the University of Regina in conjunction
with the City of Regina undextook a program to study the
generation and emission of landfill gases at the Regina
Fleet Street Landfill. The first objective of this research
was to investigate available methodologies for measuxing and
modeling landfil1 gas generation and emissions. An
additional objective was to develop and apply a landfill gas
investigation strategy to a semi-arid landfill. A further
objective was to examine landfill gas quantity and quality
information and the influence, on these, of various site
characteristics. The final objective was to provide the City
of Regina with suitable data for evaluating the potential
risks and benefits posed by landfill gas at the Regina Fleet
Street Landfifl.
Chapter Two of this thesis includes background information
on how iandfill gas is generated and the factors that affect
its generation. Information is given in Chapter Three on the
various methods that are available for determining the
quantity and quality of landfill gas. Following this
background information, Chapter Four provides a detailed
description of the methodology used at the Regina Fleet
Street Landfill and the Saskatoon L a n d f i l l to investigate
the emission of landfill gas. Chapter Five covers background
information on the landfill sites that were studied. The
study results are presented in Chapter Six, and these
results are discussed in Chapter Seven. The conclusions and
recommendations of this study are reported in Chapter E i g h t .
2 . 0 Background Information on Landfill Gas Generation
2.1 Mechanisms of Landfil1 Gas Generation
The anaerobic breakdown of organic waste, as depicted in
Figure 2.1, is a multistage process that is carried out by a
variety of organisms. Thexe are three primary microorganisms
involved in the decomposition process. The first two types
of microorganisms break d o m primarily cellulose and
hemicellulose, which constitute from 45 to 60% of municipal
waste and are its two prirnary biodegradable constituents
(Barlaz et al., 1990). Cellulose and hemicellulose are
broken down into three main components: hydrogen (HZ),
carbon dioxide (C02) and acetate (Gardner and Probert,
1992). Certain microorganisms, prirnarily methanogenic
microbes, which are responsible for the generation of
methane gas, use these three products in the generation of
landfill gas.
The quantities and types of landfill gas that are generated
will Vary over the l i f e of a landfill depending on the
stages of decomposition. A landfill site does not have the
conditions necessary for the production of noticeable
amounts of gas until it has aged. Most landfills do not
begin to show significant quantities of landfill gas until
t h e waste has been enclosed for at l e a s t 2 t o 3 years
(Gardner and Probert, 1992). Gas gene ra t ion can con t inue f o r
up t o 100 years , w i t h t h e bulk of the gas being gene ra t ed
within 20 t o 30 years after placement.
1 MONOMERIC COMPOUNDS 1
1 ALCOHOLS, CARBOXYLlC ACIDS. VFAs & l-b 1 I I
ACE TOGENESIS
Figure 2 . 1 - Major s t e p s i n t h e convers ion of organic matter to landfill gas (Gardner a n d P r o b e r t , 1992) .
The composition of l a n d f i l l gas w i l l a l s o Vary over t h e l i f e
of a l a n d f i l l . I n t h e early stages of decornposition, a
l a n d f i l l will t end t o gene ra t e primarily carbon d i o x i d e and
very l i t t l e methane, in terms of volume. However a s a
l a n d f i l l ages, t h e r e l a t i v e amount of carbon d i o x i d e
produced will s t a r t ta dec rease and t h e amount of methane
w i U i nc sease . This change i n gas composit ion w i l l con t inue
until the l e v e l of methane produced is s l i g h t l y h i g h e r t h a n
t h e amount of carbon dioxide produced. The generation curves
of v a r i o u s components of landfill gas can be seen in F i g u r e
2.2.
F i g u r e 2 . 2 - Landfill gas generation curves (Tchobanoglous e t a l . , 1 9 9 3 ) .
In addition to the p r i m a r y gases generated within a
landfill, methane and carbon d i o x i d e , other trace gases are
produced. Trace gases, s u c h as benzene and vinyl c h l o r i d e ,
will b e given o f f in srna11 quantities b u t can pose health
and environmental risks (Brosseau and Heitz, 1 9 9 4 ) . These
gases are not created by t h e breakdown of s i m p l e organic
matter b u t by the decornposition of industrial products or by
the volatilization of c e r t a i n waste compounds, such as
polyvinyl c h l o r i d e ( P V C ) , and a r e t h e n carried t o t h e
l a n d f i l l s u r f a c e by o ther escaping l a n d f i l l gases. The
pr imary sources of these trace gases are s o l v e n t s and
p e t r o l e u m products ( G r e a t B r i t a i n , 1992b) . The relative quantities of each type of gas produced by a l a n d f i l l can be
seen in Table 2.1.
Table 2 . 1 - P e r c e n t a g e s of v a r i o u s l a n d f i l l gas cornponents ( U n i v e r s i t y of California Davis, 1989).
Landfill Gas Component .
Petcent by volume-
Methane 45-60
Carbon dioxide 40-60
Oxygen
Ammonia Sulf ides,
D i s u l f i d e s , Mercaptans, etc
0.1-1.0
0.1-1.0
0-1.0
Hydrogen
[ Trace Constituents ( 0.01-0.6
0-0 - 2
Carbon Monoxide 0-0.2
2 . 2 Factors Aff ecting Landfill Gas Generation
Numerous factors have an impact on the landfill gas
generating potential of a landfill site. Some of these
f a c t o r s are i l l u s t r a t e d i n Figure 2.3, which shows the
breakdown of cellulose. The most important of those factors
are discussed f u r t h e r .
Waste Composition & Types Moisture
Temperature Nutrients & & PH Microbes
Figure 2.3 - Factors affecting landfill gas generation (McBean and Fortin, 1980).
The moisture content within a landfill site has been shown
to be one of t h e most, if n o t t h e m o s t , important factor
affecting the generation of gas ( B a r l a z et al., 1990;
Munasinghe and Atwater, 1 9 8 5 ) . A minimum amount of moisture
is required for the survival and proliferation of the
microorganisms that produce landfill gas. High moisture
content is also required for leaching of various nutrients
f rom the waste to occur (McBean et al., 1995) . Once the nutrients are removed from the waste products, t h e y can b e
more effectively acted upon by the various microbes present
in a landfill site. Landfill leachate also helps to spread
the nutrients and microbes throughout a landfill, thereby
enabling the e n t i - r e site to generate gas. In some cases, a
h i g h moisture content can hinder methane production by
increasing the hydrolysis rate to a level that will create
very acidic conditions not conducive to landfill gas
generation (Barlaz et al., 1990) . Studies have shown that landfill gas generation increases significantly as moisture
content reaches the field capacity of the waste, 45 to 60%
(Environment Canada, 1991), and increases only marginally a s
moisture content approaches 80% (Gardner and Probert, 1992;
Munasinghe and Atwater, 1985). This is far greater than the
typical 20 to 30% (v/v) moisture content found in most
landfills a t the time of waste placement (Gardner and
Probert, 1992) .
The nutrient content of the waste in a landfill is an
important factor in the generation o f landfill gases. The
nutrients from the waste are used for microbial growth,
which in turn, leads to landfill gas generation (Barlaz et
al., 1990) . For maximum gas generation, hydrogen, carbon,
nitrogen and phosphorous must be present (Gardner and
Probert, 1992; Barlaz et al., 1990). Not only must these
elements be present, but t h e y must also be present in
sufficient quantities to allow for microbial growth. The
c a r b o n nitrogen balance is of pr imary importance for
microbial growth. Studies have shown that the optimal carbon
nitrogen ratio is approximately 30:l on a weight basis
(Gardner and Probert, 1992). The presence of toxins, such as
heavy metals, are harmful to microbes and can slow down or
stop rnicrobial growth and subsequent landfill gas generation
(Emcon Associates, 1980). In addition, the intrusion of air
into a landfill is toxic to the anaerobic microorganisms
responsible for the bulk of landfill gas generation. Air can
be pulled into a landfifl if blowers used to collect
landfill gas produce too much suction and draw atmospheric
air through the cover into a landfill.
Temperature is another important factor for a l 1 biological
growth, including rnicrobial growth within a landfill.
Microbes can survive within a relatively large range of
temperatures, 15 to 55OC, but they only thrive in a much
smaller range of temperatures, 32 to 35OC and 45 to 50°C
(El-Fade1 et al., 1996). The m a j o r i t y of the heat in a
landfill is generated within the first 45 days of placement
due to the aerobic breakdown of the waste (Environment
Canada, 1991). The i n t e r n a 1 temperature will t h e n decrease
d u r i n g the subsequent anaerobic stages.
Most deep landfills are very efficient in heat retention and
this usually insures that the temperature within a landfill
remains relatively constant for most oi the year (McBean et
al., 1995). The average temperature within various landfills
is extremely site specific and can reach as high as 40°C, or
higher, in certain landfills (Emcon Associates, 1980).
During long stretches of either cold or hot weather, the
temperature within a landfill site can Vary, particularly in
the upper reaches of a landfill (McBean et al., 1995).
Temperature is one of the reasons why landfill gas
generation is higher in the summer t h a n in the winter
months. The e f fec t of temperature on landfill gas generation
is a concern in climates where there is a greater range of
temperatures throughout the year, s u c h as in Saskatchewan.
Another important landfill characteristic is pH. Landfill
gas production is possible when the moisture within a
landfil1 has a pH l e v e l between 6 and 8, with peak methane
gas production occurring when the pH is from 6.8 to 7.4
(Barlaz et al., 1990). Acid is created during the normal
decornposition of waste. This acid is used by methanogenic
microbes to produce methane gas and caxbon dioxide (El-Fade1
et al ., 1996) . If, however, there are too few microbes to use a l 1 of the produced acid, the pH will decrease and a
landfill can become toc acidic for the microbes, thereby
decreasing methane production. The base of a landfill is an
area where acidic leachate can accumulate which can make
this area unsuitable for the generation of landfill gas.
A final factor t h a t will impact landfill gas generation is
the composition of the landfilled waste. C e r t a i n w a s t e
components, s u c h a s food products, can break down more
easily to produce landfill gas. Other products, such as
scrap wood, will breakdown slowly or n o t at a l l . Landfill
waste that contains a high degree of easily biodegradable
material w i l l produce large quantities of landfil1 gas soon
after placement and will b r e a k down quickly. Waste t h a t is
not broken down very easily will produce smaller quantities
of landfill gas oves a longer period of time.
2.3 F a c t o ~ s Affecting Landfill Cas Emission
Many factors can influence t h e pattern of gas emission a t
and away from a landfill site. Two of the more important
factors influencing the frequency and location of gas
emissions are atmospheric pressure and landfill
permeability.
Landfill permeability has s evera l impacts on the emission of
landfill gas. An impermeable layer in a landfill will create
a barrier to the flow of gas and can force it away from a
landfill site. Cas, like water, follows the path of least
resistance. This means that permeability can dictate the
points of release for landfill gas and the amount of gas
that is released at each e x i t point. Frozen soil and soil
saturation have similar impacts on the location of landfill
gas emissions. When landfill gas meets a barrier, the gas
will flow under it until the gas is sufficiently d i s p e r s e d
or can escape to the surface (Conestoga-Rovers & Associates
Limited, 1995a). If t h e gas can not be released on a
continuous basis, it may build up and be released in large
quantities when conditions allow (Boltze and de Freitas,
1997) .
These factors also help to explain why landfill gas, which
is being generated throughout a landfill, is not released
uniformly. Landfill gas may be channeled, from large volumes
of waste , to specific locations and released in large
quantities.
Atmospheric pressure has shown a negative correlation to the
ernission of landfill gas (Connelly, 1983). A t times of
decreasing barometric pressure the gas concentration
increases at points at and away £rom a landfill site,
Studies have shown t h a t it is t h e rate of change i n
pressure, n o t the final pressure, which has the greatest
impact on the rate of landfill gas emission (Young, 1992;
Young, 1990). It is believed that the pressure drop allows a
large amount of air to be released from the site. This
release of air will decrease oves time even i f the rate of
pressure drop remains constant. The release of air from the
upper r e a c h e s of t h e l a n d f i l l allows l a n d f i l l gas from
deeper areas in a landfill to rnove up and out of a landfill.
As the pressure stabilizes, the gas released from a landfill
decreases and air is able to diffuse back into the landfill
cover, and emissions return to steady s t a t e .
While most research supports the theory that atmospheric
pressure has an impact on the rate of landfill gas
emissions, some field studies g i v e different results. A
study conducted by Environment Canada on £ ive landfills in
very close proximity d i d not show a correlation between Lon
pressure and peak landfill gas ernissions (Williams and
Williams, 1995). A t the f i v e landfills studied, peak
emissions occurred on different dates. I t can be assumed
that they al1 experienced the sarne, or very close to the
same, pressure and should have therefore shown similar
impacts from the changes in that pressure. The reason for
the occurrence of peak landfill gas emissions at d i f f e r e n t
times is not known.
Atmospheric pressure has also been shown to affect the ratio
of methane to c a r b o n dioxide emitted. Methane will be
released in g r e a t e r quantities t h a n carbon dioxide
imediately preceding a dxop i n atmospheric pressure. Carbon
dioxide's higher partial pressure allows it ta dissolve more
easily than methane in moisture found near the surface of
the landfill. This process gives the appearance of a greater
percentage of methane being generated t h a n is actually
occurring. If low atmospheric pressure remains steady for an
extended period, the carbon dioxide being ernitted will
become great enough to overcome absorption and the true
ratio of methane to carbon dioxide being emitted will be
reached (Young, 1992) .
Another factor affecting t h e emission of landfill gases is
the fact that because carbon dioxide has a greater density
than methane, i t can settle at the base of a Landfill. This
can slow the release of carbon dioxide relative to the
release of methane. Also a f f e c t i n g the release of landfill
gases i s the aerobic oxidation of rnethane in the landfill
cover. From 10 to 30% of methane generated in a landfill may
be o x i d i z e d to carbon d i o x i d e i n t h e l a n d f i l l cover
(Environment Canada, 1 9 9 1 ) . This could give the impression
that more carbon d i o x i d e and less methane are being released
than in actually the case.
3.0 Design Considerations for a Landfill Gas
S tudy
3.1 Landfill Gas F i e l d Investigations
There axe many considerations involved in conducting a
landfill gas field investigation. Some understanding of
landfill gas emission and migration patterns are required
before a field study can be conducted.
Studies have shown that gas is not emitted from a landfill
site on a continuous basis (Connelly, 1983; Williams and
Williams, 1995). Instead, it has been shown that gas may be
ernitted from a landfill site in pulses (McBean and Fortin,
1980). By pulses, it is meant that the amount of rnethane gas
reaching a location in a landfill w i l l rise and fa11 over
time; it will not rernain constant. Therefore, i t is very
difficult to determine t h e maximum amount of landfil1 gas
that is actually being emitted from a landfill site. Study
results may be somewhat misleading if it is assumed that gas
emissions are constant over time. Landfill gas emissions
will Vary throughout a range of values. A short-term field
study is only a s n a p s h o t in tirne of landfill gas emissions.
This s n a p s h o t in t i m e may not b e indicative of t h e maximum
o r minimum landfill gas emission rate, but may be somewhere
in the range of actuai gas emissions. However, this does not
invalidate t h e use of short-term studies. A s h o r t - t e m study
will give an indication of t h e emissions a t that time, and
whether the ernissions are high or low relative to other
landfills. A short-term study is generally sufficient to
decide whether control measures are required.
A second error that can occur when conducting landfill gas
studies is due to the mistaken belief that similar results
can be obtained when sampling at the same location at
successive intervals. This mistake arises from the belief
that gas is released in a continuous manner. In order to
obtain sirnilar results on different occasions, monitoring
must be conducted at the same tirne relative to the gas
emission pulses. However, if the gas is being released at a
certain point due to physical factors at a landfill, surface
conditions etc., then monitoring at the same location will
be important- Monitoring at a location where emissions are
high due to physical characteristics c m give valuable
information on changes in emission rates over tirne. Areas of
low emissions can also be monitored to determine if, at any
time in the future, they begin to provide significant
quantities of landfill gas indicating the need for landfill
gas control measures.
3.1.1 Monitoring Locations
An important component in any landfill gas field
investigation is determining the exact locations to conduct
gas monitoring* Ideally, an infinite number of locations
should be monitored, but in reality time and monetary
constraints mean t h a t only a small numbex of locations can
actually be monitored. If monitoring is to be carried out
over long periods, it is important to monitor the sarne
locations to enahle the results t a k e n on different dates to
be compared.
Field studies (Connelly, 1983; Williams and Williams, 1995)
have shown that gas emissions can be highly variable between
locations on a Landfill site, even between sampling
locations in close proximity CO each other. Landfill gas
studies (Bagchi, 1996) h a v e also shown a high degree of
variability between recorded values taken at the same
location but at different elevations within a single
landfill gas extraction well. Because of the high degree of
vzriability between recorded values at various depths and
locations, it is essential for any long-term study that care
be taken to i n s u r e that the same locations and elevations
are monitored over time.
The primary reasons for conducting most gas studies are to
determine how much gas is being emitted from a landfill
site, and how much gas is migrating away from the site and
into surrounding areas. Therefore, it is important to
conduct any monitoring across the e n t i r e surface of a
landfill to its perimeter and possibly beyond. This does not
mean that al1 areas have to be sampled. Emissions can be
estimated based on data from other similar areas t h a t have
shown comparable emissions rates i n the past. By monitoring
landfill gas at a landfill site's perimeter, any g a s that is
migrating away from a landfill site will be detected. In
addition to monitoring at the perimeter, monitoring on the
surface of a landfill will give d a t a that can be used in
determining a total ernission rate for a landfill (Williams
and Williams, 1995). Any permanent monitoring locations
should be placed in l o c a t i o n s that will n o t be disturbed by
activities such as landfill traffic, waste t i p p i n g o r the
f i n a l closure o f a landfiIl s i t e .
It is also important to concentrate gas sampling at t h e
locations t h a t have the highest emissions. Because landfill
gas emissions Vary spatially over a landfill, i t may be
necessary to determine t h e areas of high emissions by means
of past studies, preliminary s tud ies or interviews with
landfill operators. The areas of high emissions are of far
greater interest than a r e a s of low emissions because a
majority of landfill gas rnay be emitted £rom a relatively
small nurriber of points on a landfill surface.
3.1.2 Monitoring Frequency
The fact that landfill gas can be emitted and migrate from a
landfill site in pulses (Connelly, 1983; El-Fade1 et al.,
1995) should be taken into account when determining a
monitoring frequency for long-term monitoring programs. If
this is not taken into account, monitoring may take place
between pulses, which could give a false impression of the
amount of gas being emitted from a landfill site. Several
important steps must be t a k e n in order to determine the
optimal monitoring frequency for landfill gas.
Some gas emission and migration studies have shown that
landfill gas fluctuations will follow a pattern as long as
the conditions within and around a landfill remain constant
(McBean and Fortin, 1980; Connelly, 1983) . If the frequency of peak emission can be determined by means of intensive
sampling, t h e n sampling can take place at those times as
long as conditions remain constant.
The frequency of gas emission will Vary with regards to
temperature changes, changes in conditions within a landfilf
site and atmospheric pressure changes (McBean and Fortin,
1980; Connelly, 1983). Because of this variability, it is
important that any gas monitoring program has a certain
degree of flexibility in order to handle the effects of
changing conditions on landfill gas emissions. A l s o ,
sampling under varying conditions will give insight into the
impact of different conditions on landfill gas emission.
Peak gas emission at one location may not coincide with peak
landfill gas emission at another (Erncon Associates, 1980).
The important considerations for short-term studies are
different than for longer-term studies. In longer-term
studies, sampling is designed around the time of peak
landfill gas emissions, however, i n short term studies this
can not be done. While long-term landfill gas studies
examine temporal changes in gas emissions, short-term
studies provide a rapid assessment of l a n d f i l l gas emissions
a t a s i n g l e p o i n t i n time. The most important factor for
short-term studies is to obtain as many samples as possible
over the entire landfill surface in as fast a tirne as
possible to get an indication of emissions at one point in
tirne and under uniform conditions.
One additional consideration is the location of the landfill
in question, and the risks posed to the environment and the
surrounding population by landfill gas. Urban landfills that
are in close proximity to residences may require more
frequent monitoring to insure that there îs no risk or
nuisance to the public. This level of frequent sampling may
not be required for landfills located in more remote areas.
3.1.3 Landfill Parameters to Monitor
The two most important landfill gases to monitor are methane
and cafbon dioxide. These are not the o n l y landfil1 gases
generated, but t h e y are the most p r e v a l e n t gases and
significant in terms of both environmental impact and
potential utilization (Emcon Associates, 1980). Trace gases
should also be rnonitored because, while they may be present
in relatively small quantities, they can pose significant
health risks. The primary trace gases of interest are VOCs,
such as benzene and vinyl chloride.
Atmospheric and ground temperatures shouid be rnonitored in
addition to landfill gases. Landfill gas generation and
emission can be temperature dependent (Erncon Associates,
1980). It is important to know the temperature at the time
of monitoring in order to interpret data properly. Certain
monitoring procedures require temperature data for the
calculations that are used to determine landfill gas
emissions.
Landfill gas modeling is quite often conducted in
conjunction with a landfill gas investigation. In order to
accurately carry out landfill gas modeling, it is important
to collect landfill data that c a n be used to calibrate the se
models. Some of the data that would be most u s e f u l are
moisture content, pH, temperature, composition, and t h e
location and age of v a r i o u s landfill wastes , Waste and soi1
sampling can prov ide an indication of t h e s e parameters
either by use of a borehole or a trench, or estimates from
previous studies. The d a t a need to b e collected only once if
landfill conditions remain constant, but updated if landfill
conditions change. Because conditions can Vary within a
given landfill, it may be necessary to co l l ec t waste samples
in a number of locations a t the same landfill. Field data
also prove useful in estimating the landfill gas generation
potential for a given site.
3.1.4 Methods
There are essentially three standard methods for monitoring
gas at a landfill site: passive non-intrusive sampling,
passive intrusive sampling and active intrusive sampling.
The term active refers to actively pulling gas samples from
a landfill, for example by means of a blower. Intrusive
sampling refers to collecting samples by penetrating the
surface of a landfill, for example with a well, while non-
intrusive sampling collects samples at the landfill surface.
Passive non-intrusive sampling collects landfill gas sarnples
in the air above the landfill surface or directly on the
landfill surface. The main advantages of passive non-
intrusive sampling are that it is easy and inexpensive to
conduct, and sampling can be conducted at a variety of
locations at and around a landfill site in a relatively
short period of time. Also, because this type of sampling is
very mobile, it can be used in s u c h a way as to not
i n t e r f e r e w i t h landfill operations. The major disadvantage
of passive non-intrusive sampling is that it can give less
accura te results than more active intrusive sampling (Great
Britain, 1992a). The gas that escapes from a landfill site
is sampled not the gas generated within the landfill itself.
However, this may be e x a c t l y what is desired if the purpose
of a study is to determine the amount of escaping landfill
gas in order to determine c o n t x o l measures. Other methods
may be needed to determine the amount of gas being generated
in o r d e r to determine the potential for landfill gas
utilization.
There are a nurnber of methods that are available for passive
non-intrusive sampling. One of these methods is an ambient
air sampler . Ambient air samplers collect and analyze gas
samples at a landfill's surface. These samplers can measure
individual gases, such as methane, or combustible vapours.
The benefits of this type of sampler are that it is
relatively cheap and easy to use. Ambient air samplers can
be used effectively in preliminary work for determining the
areas of the landfill t h a t have the highest gas emissions.
The primary disadvantages are that ambient air samplers do
not allow an emission rate to be determined and c a n not
speciate b e t w e e n various gases in a single sample.
Another type of passive non-intrusive sampler is a flux
chamber. A small portion of a landfill cover is enc losed
within a hemisphere, into which a known quantity of c l e a n
sweep gas is introduced. The sweep gas allows for t h e
determination of an emission rate and acts to dilute the
landfill gases that in h i g h concentrations can be damaging
to analysis equipment. The clean sweep gas then mixes with
the emitted landfill gas, and after a short time, the mixed
gas is withdrawn for analysis. By assuming that the flux
chamber acts as a completely mixed reactor and that the
inflow of landfill gas is much srnaller than the inflow of
t h e s w e e p gas, an emission rate for various types of
landfill gases can be determined. By collecting a large
number of samples over the s u r f a c e of a landfill, an
emission rate for a landfill can be determined. The
advantages of this type of sampler are that it is cheap and
relatively easy to use, and allows f o r ga s speciation and
the determination of an emission rate.
There are a number of disadvantages to using a flux charnber
for landfill gas sampling. Because only a small area is
covered by the flux chamber, a large number of samples are
needed in order to determine a n accurate emission rate for
an entire landfill. Because very small quantities of
landfill gas are analyzed, there is the possibility of cross
contamination. Cross contamination can be addressed by
carefully covering the flux chamber during sampling and
carefully cleaning collection equipment after each use.
Another problem found in some flux chamber designs is that
as the f l o v of sweep gas is increased to compensate for high
landfill gas emission rates, internal pressure can build up
which may impede the inflow of landfill gas into the flux
chamber. This problem is addressed by increasing the area of
the gas outlet to reduce internal pressure (Williams and
Williams, 1995), or by keeping the sweep gas flow rate low
(University of California, Davis , 1989) . Even taking into
account these problems, studies have shown that if used
properly, flux charnbers can effectively and accurately
determine landfill gas emissions (Williams and Williams,
1995; Eklund, 1992; Reinhart et al., 1992) .
A second method for landfill gas sarnpling is by passive
intrusive sampling using shallow depth gas probes. These
probes are generally based on the Method 25-C design,
provided by the United States Environmental Protection
Agency ( U . S . EPA) for use in collecting landfill gas
samples. These probes are comprised of a 1 to 2 m hollow
pipe that is open and perforated at the bottom and sealed at
the top with a valve that allows for the withdrawal of a gas
sarnple. The shallow well is placed I m into the landfill as
shown in Figure 3.1.
Pump
Figure 3.1 - A shallow gas collection well.
After the conditions within the well have reached steady
state, at l e a s t 24 hours, a gas sample can be withdrawn. The
sample is withdrawn by pumping the sample into a collection
canister. The sample can then be sent for a n a l y s i s . The
advantage of the gas probe is that it provides more use fu l
data t h a n ambient air sarnpling, because it collects samples
£ r o m within the l a n d f i l l i t self as opposed to collecting
samples at the l a n d f i l l surface. Also, t h e s e probes are
relatively cheap t o cons t ruc t and easy t o use, thereby
enabling multiple probes to be set up and used a t a landfill
site. The major disadvantages to the probe are that it only
samples to a relatively shallow depth within a l a n d f i l l , and
it i s not possible to determine emission rates over an
e n t i r e landfill site. Shallow gas wells are i d e a l l y suited
for collecting point gas samples that can be sent to a
laboratory and analyzed in greater detail than can be
accomplished in the field, such as when analyzing for VOCs
or other trace gases.
The final method of gas sampling is by intrusive active gas
sampling, primarily by the use of deep landfill collection
wells. These wells can either be used individually or they
can be connected to a larger gas collection systern. The key
factors i n the installation of a collection system are that
it must reach al1 parts of a landfill and it must have a
suitable and powerful blower. The blower for the wells must
be powerful enough to pull landfill gas out, but it should
not pull air into the landfill because this will hinder
landfill gas generation (Van Zanten and Scheepers, 1990).
The benefit of this type of collection system is that it
can, if i n s t a l l e d properly, collect landfill gas from the
majority of the landfill and can give very detailed data.
The extraction efficiency for a properly designed c o l l e c t i o n
system can be in excess of 85% (Hickling, 1994) . The major
problem in the use of this type of system is t h e price.
Because o f the variable nature of landfills, a large number
of wells would be required- In addition, because some
landfills contain a large amount of rubble, drilling wells
for a collection system may be extremely difficult. This
type of sampling would be useful if a large enough quantity
of landfill gas is believed to be present to warrant
collection for large scale destruction or utilization.
A modified active intrusive sampling procedure can be used
if more detailed information is desired on the quantity and
quality of gas being produced at a landfill site. This
method involves drilling a gas well and surrounding it with
gas probes circling the well at various distances and
depths. The purpose of this type of procedure is to
determine the "zone of influence" for a given gas well. By
pulling gas from the well and monitoring the pressure in the
probes, a rough estimate of the area that is being
influenced by that well can be determined. %y knowing the
volume of w a s t e and the quantity of gas being drawn from
that volume of waste, an estimate of the amount of gas
generated per unit volume of waste can be determined. This
is very useful data required to examine the viability of a
gas utilization system. The problem with this type of
analysis is that it is very expensive and time consuming,
and should only be carried out if it is believed that there
is a large quantity of gas being generated.
3.2 Modeling of Landfil1 G a s Genetation
Since accurate r e s u l t s from field tests are difficult and
expensive to obtain, landfill gas modeling can be used in
place of field investigations or as a supplement to them.
Because the basic equations for the breakdown of landfill
material into landfill gas, such as the one seen in Figure
2 . 3 , are known, the simplest method for estimating landfill
gas generation is by stoichiometric methods. Using
stoichiometric methods, an es t imate can be made for the
telease of methane from a landfill; one estimate is 270 L of
CH4/kg of wet refuse (Emcon Associates, 1980). Even higher
estimates c a n be obtained if the waste is assumed to be
composed of only cellulose material. These estimates are
based on ideal conditions and require specification of a
chernical formula for the waste. Because actual landfill
conditions and waste are not homogenous or static, more
cornplex rnethods must be used to estimate landfill gas
generation over time.
There are a number of more cornplex methods available for
rnodeling landfill gas generation. Al1 of the methods attempt
to predict t h e outcome of the various reactions within a
landfill that produce gas. Generally, landfill gas models
try to account for the influence of key parameters, such as
temperature and moisture content.
The major problern w i t h landfill gas modeling is that there
can be a large amount of uncertainty in the background data
required by various models. In many landfills, particularly
older landfills, there may be a general lack of information
on the locations, ages and types of waste present. There may
also be a lack of information on the key conditions w i t h i n a
landfill, such as moisture content and pH.
Another factor that can negatively a f f e c t the outcome of
landfill gas modeling is t h a t conditions within a landfill
are extremely variable. This may mean that modeling a
landfill as a single homogeneous unit is not suitable and it
may be necessary to rnodel each homogeneous subpart
independently. In order to rnodel subparts, however, very
detailed information will be required, and in many cases
this information may not be available.
Another issue in modeling studies is determining the
accuracy of the final results. In cases where actual field
data are not available, the mode1 will be the sole source of
information on landfill gas g e n e r a t i o n . The accuracy of
landfill gas models will depend to a very large extent on
both the quantity and quality of the input data. Models that
are cafibrated based on data from other similar landfills
have been shown t o corne within t30% of actual gas generation
(Zison, 1990), while with good accurate long-term site
specific data results of f10% can be achieved. Of course,
the mode1 results are being compared to field data which
will also have some error associated with thern.
At present, there are very few, if any, models available
that are capable of relating al1 generation influencing
parameters to landfill gas generation, or of determining the
effects of the var ious parameters on each other. Instead of
relating individual parameters to landfill gas generation,
most models group the cumulative ef fec t of the parameters
into one or two coefficients that c a n be modified for
various landfill conditions.
The best possible site-specific data should be used to
insure the best modeling results for a given landfill are
obtained. For modeling studies, it is also important to
obtain the most accurate information on past, present and
future landfill conditions. The primary site data required
by most models are waste quantities and the amount of waste
in place. Because estimates f o r various coefficients needed
by most models, such as decay coefficients, are not usually
available or are difficult to obtain, estimates of these
coefficients must be made.
There are three primary types of rnodels used for estimating
landfill gas generation:
1. Zero order kinetic models;
2. First o r d e r kinetic models;
3. First o r d e r multiphase kinetic models.
Zero order kinetic rnodels operate under the assumption that
landfill gas generation is constant over time. Essentially
this means that the age of the waste is not taken into
account. T h e s e models are not useful in the majority of
landfill studies but can be used to determine emissions
nationally or globally (Peer et al., 1993). They can also be
used in cases where there is very slow landfill gas
generation and landfill conditions remain constant over
tirne. A zero order kinetic equation can
3.0 (McBean et al., 1995) :
be seen in Equation
(3 0)
Where : time between waste placement and landfill gas generation; volume of CH4 remaining to be produced a f t e r time T; gas production rate constant.
First order kinetic models differ from zero order models in
that time is taken into account. These models are cornrnonly
used because they are simple and have been shown to give
accurate results (Zison, 1990). The primary equation that
first-order kinetic models are based on is Equation 3.1
(Erncon Associates, 1980) :
Through Equation 3.1, it is possible t o determine the
generation of landfill gas over tirne b y assuming that t h e
gas production rate decreases exponentiafly.
First order multi-phase kinetic models are a variation on
the standard first-order model with the only difference
being that the waste in a landfili. is broken into various
subparts. The subparts of a landfill are based on the speed
by which the various types of waste will be broken down.
Usually three subparts are used: slow biodegradability, such
as plastics; medium biodegradability, such as wood; and
rapid biodegradability, such as food scraps. This type of
model can be more accurate t h a n the standard first-order
kinetic model, if proper data are available on the t y p e s and
ages o f waste present in a landfill (Oonk et al., 1994). The
problem with this type of model is that it requises very
detailed information on the quantity of each type of waste
present, the rate of decomposition of each type of waste,
and the quantities of each type of waste brought to a
landfill every year. Very often this information may not be
available.
The variability within a landfill and the possible l a c k of
information on landfill characteristics and inputs make
modeling landfills very difficult. These difficulties mean
that there will be a degree of uncertainty with any modeling
results. If possible, the results should be verified w i t h
actual field data.
4 . 0 Methodology
Because of the complexity of the Regina Fleet Street
Landfill gas investigation, it was carried out in a number
of phases. The initial phase was a survey of the landfill to
create a grid system that could be used to orient the
landfill gas sampling. Following the construction of the
landfill grid system, a preliminary gas investigation was
undertaken to gather information necessary for designing the
detailed landfill gas investigation.
Following the preliminary phases of the landfill gas
investigation, a detailed landfill gas investigation was
carried out. In addition to the detailed landfill gas
investigation, two shallow gas wells were installed in otder
to collect samples for gas speciation. To assist in the
interpretation of the collecteci data, waste samples were
collected at various locations and depths in the landfill
and analyzed for a variety of parameters. To complete the
landfill gas study, computer simulations of the landfill
were preformed to aid in long term gas generation
predictions.
4 . 1 Regina F l e e t S t t e e t Landfil1 G r i d System
Before field data collection, it was necessary to develop a
grid system based on a survey of the Regina Fleet Street
Landfill. This grid system would be used to orient the
sample collection process and to insure that al1 required
sectors were sarnpled. A City of Regina survey crew laid in a
30 m b y 30 rn grid. The grid began in the southeast corner of
the landfill and ended in the northwest corner. The grid ran
east to West and north to south. The 30 m by 30 m grid s i z e
was based on discussions between the University of Regina,
Environment Canada and the City of Regina. The final
decision to u s e a 30 m by 30 m grid was based on a
compromise between getting the finest possible grid that
could be s u r v e y e d in a reasonable time frame of one to two
weeks. An additional consideration was that large numbers of
grid stakes c o u l d be knocked down by the daily operations at
the landfill site. This would încrease the difficulty in
determining exact sampling locations.
The survey crew constructed the grid by placing a painted
stake with florescent tape at the vertex of each g r i d
square. The stakes were lettered and numbered using a
reference system requested by the University of Regina. This
reference system allowed any square to be easily located on
the landfill site.
Because each survey stake had exact reference coordinates,
it was possible to locate the grid and indicate emission
rates on landfill maps. Certain areas that were eithex
located in a curxent active area, an inaccessible area, or
within the landfill maintenance yard were not surveyed.
4 . 2 Preliminary Landfill Gas Investigation
A detailed study was reqüired in order to obtain data that
would aid in the determination of landfill gas emission
rates as well as landfill gas speciation. Because detailed
landfill gas sampling would be very time consuming, every
grid square at the landfill could not be sampled in a
reasonable time frame. A preliminary study was used to
determine tne areas of high gas concentrations so that they
could be studied in greater detail. It was possible to
design a detailed study that, while not sampling every
location, would sample the most important locations in terms
of gas emissions. The preliminary study allowed the detailed
study to be carried out in only a rnatter of weeks instead of
montns.
To conduct a rapid preliminary study, a flame ionization
deteccor (FID) w a s used to collect surface landfill gas
samples. A FID collects a gas sample from the air and burns
it within the analyzer. The FID t h e n gives a reading in
parts per million (pprn) of combustible vapour present in the
analyzed sarnple. Because methane, a key landfill gas
component, is combustible it was decided, for the purposes
of the preliminary study, that high €ID readings would be
taken as an indication of high landfill gas emissions.
Determining these areas would give a strong indication of
the locations where there would be greater landfill gas
emissions, which could later b e studied in detail. The FID
also allowed for the determination of the areas that had
sirnilar emissions so that a few representative samples could
be taken from those areas.
The FID, a HeathTech THC analyzer, was borrowed, for the
duration of the landfill gas study, from the Environmental
Research and Management Division (ERMD) of Environment
Canada, located in Ottawa. This FID is designed and built by
HeathTech Consulting Ltd. for use in determining
concentrations of combustible vapour. This analyzer had been
used to determine landfill gas concentrations at a number of
landfills throughout Canada. The FID runs on an interna1
battery and a small canister of hydrogenhitrogen rnix fuel.
The entire unit is easily portable @y one person and can
operate for several hours b e f o r e being refueled and
recharged. The FID can measure concentrations of combustible
vapour from 10 to 1000 ppm (as methane) and due to
modifications made by Environment Canada it can detect
concentrations up to 2000 ppm. The gas sampLe is drawn into
the analyzer by an i n t e r n a 1 pump, through a small flexible
boot that is placed on the landfill surface. This allows
samples to be taken from the landfill surface with a minimum
of atmospheric contamination.
Samples were taken at every g r i d stake over the entire
landfill site. This included some areas t h a t had not been
surveyed, s u c h as the landfill maintenance yard. The FID
also was equipped with an alarm which sounded any time
combustible vapour levels were above a pre-set level. This
alerted the pesson conducting the field test of high
concentrations of combustible vapour as they were walking
between points. These points were t h e n sampled and the
locations referenced frorn surrounding stakes.
4 . 3 Detailed Landfiil Gas Investigation
A number of options were considered for collecting detailed
landfill gas data which would later be used t o determine
both an emission rate for the landfill, as well as landfill
gas s p e c i a t i o n .
The use of a landfill gas collection system t o pull gas from
a landfill was not a viable opt ion . There is currently no
collection system in place at t h e Regina landfill site and
the possibly l a r g e capital c o s t ta install one, would be
prohibitive. In addition, the amount of landfill gas
expected from this semi-arid landfill may be too low to
justify its collection and subsequent utilization, at least
in this preliminary stage.
A second option that was considered was the use of a series
of deep landfill gas extraction wells. Since the landfill is
extremely variable, a large number of wells would be
required in order to obtain samples representative of al1
parts of the land£ill. A second problem is that since a
large amount of rubble has been buried in the landfill, it
would be difficult to get enough boreholes drilled deep
enough into the landfill. The large number of wélls that
would be required made this option cost and time
prohibitive.
S i n c e below surface methods of collecting landfill gas
samples were al1 extremely costly, it was decided that non-
intrusive methods were the most viable option for landfill
gas collection. The method to be used would have to able to
allow for an emission rate to be determined plus allow for
gas speciation of at least methane and carbon dioxide. The
rnethod would use equipment that is portable enough to allow
for sampling of the e n t i r e landfill to take place, and
durable enough to withstand prolonged use in the field.
The method that was chosen for the collection of the
detailed samples was a flux chamber collection system. Flux
chambers have been used f o r a nurnber of years in t h e United
States for the collection of VOC data as well as other kinds
of emissions (Pohland and Harper, 1987; Eklund, 1992). Flux
chambers resemble a hemisphere that is placed on the
landfill surface in order to collect emission samples. T h e
b a s i c equations used to determine landfill gas emissions
using the flux chamber are as follows:
Where :
Froc = the total volumetric flow o f gas i n t h e
dilution tube sampler (L/min);
Fd = the metered flow of diluent gas entering the flux
chamber (L/min) ;
F, = the desired volumetric flow rate of the target
species entering the sampler over t h e area of
the flux charnber (L/min), compensated to 25'~.
Where :
C, = the measured concentration of the target species
i n the gas sample after thorough mixing w i t h the
diluent gas i n t h e f l u x chamber ( p a r t s p e r m i l l i o n
( v / W 1 -
S u b s t i t u t i n g Equation 4 . 1 i n t o E q u a t i o n 4 . 2 y i e l d s :
Assurning F, >>> Ft, then:
Re-arranging Equa t ion 4 . 4 t o solve for Ft yields:
Equation 4.5 gave an ernission rate f o r a target gas f o r t h e
a rea , 0 .0169 m2, covered by t h e f l u x c h a m b e r . T h i s emission
r a t e was used a s an average f o r the entire s q u a r e i n which
the sample was taken.
Several impor tan t considerations had t o be addressed when
u s i n g a flux c h a m b e r . F i r s t l y , b o t h t he type of sweep gas
and the flow rate of t h e sweep gas had to be considered.
Almost any gas can be used as long a s i t is pure, dry and
does n o t c o n t a i n any of t h e gases being studied. P u r e
nitrogen was chosen as the sweep gas because it is readily
available and relatively cheap. The decision on flow rate
was more difficult because there are problems with using
either a high flow rate or a low flow rate. If a low flow
rate is used, it is possible to get a more detailed reading
on the gas emissions. The problem is that using a low flow
rate can result in a much longer time for conditions within
the flux charnber to r e a c h steady state (Eklund, 1992). Also,
if there are high emissions occurring, a low flow rate c a n
make the assumption that Fd is much greater than Ft invalid.
Based on these factors, the chosen flow rates were 5 L/min,
for average landfill gas emissions, and 10 L/min, for high
g a s emissions.
Another consideration was the placement depth of the flux
chamber. It must be placed at a minimum distance into the
ground in order to insure a proper seal, thereby trapping
landfill gas in the chamber and keeping atmospheric air o u t .
A standard minimum depth of 2.54 cm is used in many flux
chambelr applications in the United States (Eklund, 1992).
Environment Canada indicated that their experiments showed
that a minimum depth of 4.45 cm would offer the best
protection against the strong winds comrnon o n the prairies
(Williams and Williams, 1995). In addition to the increased
depth for the flux chamber, two separate containers were
placed over top of the flux chamber to insure that wind did
not impact the sampling.
The final consideration was the number of samples to take.
As in most studies, it is best to take as many samples as
tirne and money allows- Based on the FID data, it was decided
to conduct extensive sampling on the slopes of the landfill
because these areas showed higher combustible vapour
concentrations than other a r e a s . The top and base areas of
the landfill, were sarnpled only sporadically, due to the low
combustible vapour concentrations found over these areas.
One sample was randomly t a k e n per studied square unless
concentrations exceeded 500 ppn for either carbon dioxide or
methane . If concentrations greater than 500 ppm were found,
t h e n two additional samples were taken randomly within the
same square. The sweep gas f l o w rate was increased to 10
L/min to compensate for concentrations greater than 500 ppm.
Figure 4.1 illustrates the flux chamber setup that was used
at the Regina Fleet Street Landfill. The flux chamber was
inserted into the ground to a depth of approximately 4.45
cm, Once it was inserteu, the sweep gas was turned on to the
desired level, usually 5 L/min. Once the flux chamber had
reached steady state, approximately 5 minutes, a sample was
drawn from t h e flux chamber by means of a small hand pump
which pulled the sample from the chamber into a Teldar
sample bag. When the sarnple was collected, the temperatures
within the flux chamber and i n the ground below the chamber
were recorded u s i n g a small themorneter. Af t e r t h e sample
was t a k e n , the f l u x chamber was relocated and the sample bag
was brought back for a n a l y s i s .
I Pump
Gas Sweep A Nitrogen
Gas
L a n d f i l l Surface
Figure 4.1 - Flux chamber appa ra tu s .
The a n a l y s i s of the samples was carr ied out u s i n g a B d K
Mode1 1302 Multi-Gas Analyzer, manufactured by Brüel & Kajar
Inc. The analyzer was located in a van t h a t could be moved
closer t o the sarnpling area. A srnall gasoline g e n e r a t o r
powered the ana lyze r . The BhK analyzer was used to measure
carbon dioxide and rnethane and was capable of measur ing
c o n c e n t r a t i o n s up t o 15 ,000 ppm of gases. The B b K a n a l y z e r
works by moni tor ing the changes i n wavelength o f i n f r a r e d
l i g h t as i t passes through the gas sample. The sarnple bag
was hooked up t o the analyzer, and an interna1 pump drew a
sample into the a n a l y z e r f o r a n a l y s i s . The gas i n each
sample bag was analyzed three times and the average of the
results was used to determine the final concentration,
To insure proper calibration of the B&K analyzer, i t was
periodically checked for zero and span concentrations. This
was d o n e on a twice-daily basis. To check for the span, pure
concentrations of both methane and carbon d i o x i d e were run
through the analyzer and the results were noted. To check
for the zero, pure nitrogen was run through the analyzer and
the r e s u l t was recorded. These resufts were latex used
modify the data to compensate for variations in the
operation of the analyzer.
The emission data for areas at the landfill that were not
sampled were estimated by averaging the emission results
from surrounding, sampled, a r e a s . The areas used to average
other areas had to have similar combustible vapour
concentrations, were i n the same area, and had similar
topography.
4 . 4 Shallow Gas Wells
Deta i led analyses had to be made not only of the primary
gases, methane and carbon dioxide, but also of very small
quantities of trace gases in order to proper ly analyze
Regina's Landfil1 gas. Because of the large number and small
quantity of these gases, the B & K analyzex could not be used
and the samples had to be analyzed in a laboratory using
more cornplex a n a l y s i s equipment. I n addition, because of the
srna11 quantities of the trace gases present, a different
sampling method had to be used.
Zt was decided to use an approach modified from one used by
the U.S. EPA to collect trace gas samples. The procedure
used by the U.S. EPA is called Method 25-C and involves
placing a shallow gas well in a landfill to collect gas
samples. Two wells were constructed of 5.1 cm s teel p i p e
perforated a t the bottom and placed 1 m into the ground. Two
wells were installed on top of the south dope of the Regina
landfill. The location of these wells can be seen in Figure
4.2.
The wells were sealed and allowed to sit for two days;
t e f l o n tubing was inserted into the wells and a sample was
drawn from e a c h well. The samples were drawn into evacuated
stainless steel SUMMA canisters- The canisters were shipped
to Environment Canada in Ottawa for analysis by means of a
gas chromatograph equipped with a mass selective detector.
' D I ,
., 3: '-.. . m --
4 . 5 Waste Sample Extraction
Waste samples were required to better understand the
conditions within the landfill and to gain some insight that
could later be used to interpret the landfill gas results.
Ideally, these waste samples should corne from a variety of
waste ages and provide information on pH, moisture content,
nutrients, temperature and organic and inorganic components
of the waste. In order to obtain waste of an o lde r age, 20
to 30 years old, a borehole was drilled through the south
d o p e from the top to the bottom of the landfill. To collect
samples of younger age waste, 1 to 5 years old, a trench was
dug on the top of the landfill. The locations of the
boreholes and the trench can be seen in Figure 4.2.
AGRA Earth and Environmental Limited (AEE) was hired to
drill the borehole and excavate the trench and to collect
the samples for analysis. In addition to the collection of
waste sarnples, AEE (1998) installed a thermistor to monitor
landfill temperatures, and a suction lysimeter and bailer to
sample leachate.
To collect the waste samples from the older section, two
boreholes were drilled. Both boreholes were 0.6 m in
diameter and were drilled using a LDH 80 piling r i g to
depths of 21.5 m and 10.7 m, respectively. The reason f o r
the second borehole was to allow for the installation of the
thermistor in one borehole, and the lysimeter and piezometer
in the other. Waste samples were collected at incrernents of
1 m in t h e 21.5 m deep borehole, and at increments of 1.5 m
below a depth of 4.6 m in the 10.7 m deep borehole.
Temperature readings were recorded at depths below 18 rn in
the 21.5 rn deep borehole, and at depths below 4.6 m in the
10.7 rn deep Sorehole .
A t rench was excavated w i t h a track-mounted backhoe to a
depth of 5 m to collect younger age waste samples. Samples
were collected at 1 rn intervals. The trench was backfilled
after the collection of the waste samples.
A l 1 waste samples were collected and placed in heavy-duty
collection bags and were subsequent ly sent to the
Saskatchewan Research Council (SRC) in Saskatoon for
analysis. The samples were analyzed for moisture content,
pH, loss on ignition, organic compounds, nutrients and
metals.
4 . 6 Modeling
The U.S . EPA Landfill Air Emissions Lstimation Mode1 (LAEEM)
is used for estirnating emission r a t e s of methane, carbon
dioxide and other individual toxic po l lu tant s from
landfills. The LAEEM is one of the most widely used landfill
emission models and its predictions form the basis for
r e g u l a t i o n s in B r i t i s h C o l u m b i a and t h e United S t a t e s
(Conestoga-Rovexs & Associates Limited, 1 9 9 5 a ) . The LAEEM i s
based on the Scholl Canyon first order single stage kinetic
model for landfill gas generation. The Scholl Canyon model
assumes that landfill gas generation w i l l b e g i n w i th no l a g
time between the time of waste placement and the beginning
of landfill gas generation. This means that the mode1
assumes t h a t peak l a n d f i l l gas generation occurs imrnediately
after the placement of the waste and then decreases over
time. The basic e q u a t i o n used by t h e LAEEM is derived from
Equation 3.1:
Where:
G , = ernission r a t e from the ith section (Mm3 of
CHJyear) ;
k = methane generat ion r a t e (l/year) ;
L, = methane generation potential (m3 of CH4/tonne
of refuse) ;
Mi = mass of refuse in the irh section ( M t ) ;
rI = age of the ith section (years);
i = sub-sections of the whole landfill.
As can be seen £rom Equation 4.6, the LAEEM requires only
four input variables, which are the amount of waste in
place, t h e age of the waste, k and L,. The user has to input
the tonnes of w a s t e in place or an acceptance rate for every
year that the landfill h a s been in cperation up to the
present year. If the waste in place or the acceptance rate
is not known then the LAEEM can estimate these values based
on landfill volumes. The LAEEM will also ask for the year
the landfill opened and the maximum c a p a c i t y of t h e
landfill. These data are used to determine the length of
time the landfill will accept waste.
T h e r e are two important variables used in th2 LAEEM. The
first is the methane generation potential of the waste , L,.
This parameter can be determined e i t h e r by field tests or
based on data £rom other landfills since it is primarily
dependent on the types of waçte present. The second variable
is the methane generation rate constant, k- This variable
determines how quickly the methane generation rate will
decrease after it has reached its peak. This variable is
much more site specific t h a n L,, since it depends on
landfill conditions such as moisture content, pH and
temperature.
The LAEEM allows the user to enter site specific values for
k and Lo or allows for two default settings for these
variables to be chosen. The first of the default settings is
the Clean Air Act (CAA) defauit values. T h e s e values are
d e s i g n e d to e s t i m a t e the maximum amount of landfill gas that
c o u l d be expected from the l a n d f i l l . The primary use of
these default values is to determine if landfill gas control
measures are required a s set out i n t h e CAA. The second set
of default v a l u e s a r e derived f r o m t h e U.S. EPA's
"Compilation of Air Pollutant Emission Factors, AP-42" which
was compiled by the U.S. EPA in 1997. These default v a l u e s
are d e r i v e d from actual l a n d f i l l s and provide estimates of
landfiil gas emissions that are e x p e c t e d to be closer to
actual values .
Once al1 of the data have been input into the LAEEM, t h e
mode1 determines t h e amount of rnethane g e n e r a t e d by a given
quantity of w a s t e oves t i m e w i t h i n a landfill f o r each year.
The LAEEM then determines the amount of carbon dioxide
generated by assuming that the g e n e r a t e d landfill gas is 50%
methane and 5 0 % carbon dioxide. This ratio can be changed if
site conditions warrant. In orde r t o d e t e r m i n e the emission
of other trace gases, such as V O C s , the LAEEM relies on
c o m p o s i t i o n a l a v e r a g e s obtained from a numùer of landfills.
S i t e specific values cari also be used for these inputs.
I n the case of t h e Regina landfill, there is a l a c k of s i t e
specific da ta . T h i s required that the LAEEM be run under a
variety of conditions and assumptions. Some of these
assumptions were t h e compaction rate for the waste, waste
a c c e p t a n c e rates b e f o r e 1 9 8 0 , t h e amount o f b i o d e g r a d a b l e
w a s t e p r e s e n t i n t h e l a n d f i l l and t h e ratio o f t h e l a n d f i l l
gases p r o d u c e d .
Even though t h e LAEEM is a v e r y s imple model, i t i s deemed
a c c u r a t e fo r u s e by t h e U.S. EPA and s e v e r a l p r o v i n c e s i n
Canada, Studies have shown t h a t t h e S c h o l l Canyon Mode1
prov ides results t h a t are comparable to those f rom o the r
rnodels, i n c l u d i n g more c o m p l i c a t e d rnodels (Peer e t al.,
1993; Oonk e t a l . , 1 9 9 4 ) . F i r s t o r d e r rnodels that a r e
p r o p e r l y calibrated have been shown t o be able t o a c h i e v e
r e s u l t s t h a t a r e &IO% of a c t u a l emissions ( Z i s o n , 1 9 9 0 ) .
Because of t h e limited accuracy of most l a n d f i l l d a t a , i t is
l i k e l y t h a t rnore c o m p l i c a t e d models may n o t be a b l e t o
p roduce more a c c u r a t e r e s u l t s . Because several p r o v i n c e s and
t h e U.S. EPA use the LAEEM, t h e r e s u l t s can be compared w i t h
t h e results f rom o t h e r l a n d f i l l s .
4 . 7 Supplemental D a t a
I n o r d e r t o u n d e r s t a n d t h e emissions data f rom t h e Regina
l a n d f i l l , a d d i t i o n a l da ta were r e q u i r e d i n c l u d i n g
i n f o r m a t i o n on t h e t y p e s , a g e s and q u a n t i t i e s of waste a t
the l a n d f i l l , and t h e yearly acceptance rates f o r va r ious
types of w a s t e . It was i m p o r t a n t that, i n terms of
u n d e r s t a n d i n g any s p a t i a l v a r i a n c e o f e m i s s i o n s a t t h e
landfill, the characteristics of the waste at a particular
location were known.
A careful review of relevant reports and background
information on the landfill was carried out. Because written
records on the landfill are incomplete, it was also
necessary to conduct interviews with City of Regina
employees w h o have first hand knowledge of the landfill.
This included taiking to engineers at the City of Regina and
operators at the landfill.
In order to determine how the emissions f rom the Regina
l a n d f i l l compare with other similar landfills, information
sharing took place with the City of Saskatoon. Saskatoon's
landfill is quite similar to Regina's in terms of types of
waste in place and regional climate. The University of
Regina helped plan and organize a detailed landfill gas
study for the Saskatoon Landfill, similar to the one
conducted at the Regina Fleet Street Landfill. This included
help in developing a survey of the landfill and in defining
a sampling area.
In addition to the information from the Saskatoon Landfill,
information on emissions from landfills collected by
Environment Canada was obtained for comparison purposes.
5.0 F i e l d S t u d y S i t e s
5.1 T h e Regina F l e e t Street Landfill
T h e Regina F l e e t S t r e e t L a n d f i l l was opened i n 1 9 6 1 a f t e r
the closure of the p r e v i o u s l a n d f i l l l o c a t e d a t Mount
P l e a s a n t . T h e l a n d f i l l i s situated a t t h e northeast c o r n e r
of Regina o n F l e e t S t r e e t 0 . 5 km n o r t h o f 9th Avenue. The
l a n d f i l l o c c u p i e s a t o t a l a r e a of 97 h e c t a r e s w i t h actual
l a n d f i l l activities a c c o u n t i n g for a p p r o x i m a t e l y 60 h e c t a r e s
of that total a r e a , and r i s e s to a height of o v e r 30 m. The
l a n d f i l l s t a r t e d o p e r a t i o n a t t h e s o u t h w e s t c o r n e r of the
s i t e and l a t e r ex tended e a s t and t h e n n o r t h . The l a n d f i l l
was constructed w i t h no l i n e r and a t p r e s e n t , t h e r e i s no
l e a c h a t e o r g a s c o l l e c t i o n system i n place.
T h e area of Regina i s deemed a r i d t o s e m i - a r i d . T h e mean
precipitation i n t h e Regina a rea is 400 mm. Of the 4 0 0 mm o f
p r e c i p i t a t i o n , 75% cornes in t h e fo rm o f r a i n f a l l . The
p r e c i p i t a t i o n that f a l l s i n Regina i s c o n v e r t e d i n t o 50%
e v a p o r a t i o n , 32% r u n o f f and 18% p e r c o l a t i o n ( R e i d Crowther &
Partners L i m i t e d , 1993)-
T h e Reg ina topography , including t h e l a n d f i l l a r e a , i s
generally f l a t w i t h low r o l l i n g hills. Regina's e l e v a t i o n
averages 590 m above sea l eve l w i t h t h e l a n d f i l l located a t
approximately 600 m above sea l e v e l . T h e Regina Fleet Street
L a n d f i l l subsurface is cornposed of c l a y u n d e r l a i n b y s i l t
t h a t ex t ends to a depth of 3 .5 to 6 . 5 m below t h e ground
surface, with an increase i n silt c o n t e n t , l a y e r i n g and
f r a c t u r i n g a s t h e depth increaseç (Reid Crowther & Par t f iers
Limited, 1 9 9 3 ) . The subsu r f ace m a t e r i a l i s t y p i c a l of the
m a t e r i a l found throughout t h e Regina area.
Both the Condie (A-Zone) Aquifer and the Regina (8-Zone)
Aquifer a r e located below t h e l a n d f i l l . T h e Condie A q u i f e r
format ion is 1 0 t o 25 rn t h i c k and is 3 to 7 m below t h e
l a n d f i l l site. The Regina A q u i f e r formation i s 4 to 40 m
t h i c k and is located 23 to 50 m below t h e landfill (Reid
Crowther 6 P a r t n e r s Limited, 1 9 9 3 ) .
T h e Regina F l e e t Street L a n d f i l l i n i t i a l l y employed t h e
trench rnethod of waste disposal. This method involves
f i l l i n g excava ted trenches with waste and then covering
t h o s e t r e n c h e s with cover m a t e r i a l . L a t e r , landfill
o p e r a t i o n s switched t o the area method of l a n d f i l l i n g which
con t inues t o t h i s day over t o p of the o l d t r e n c h e s .
T h e waste accepted a t the landfill for the majority of its
h i s t o r y h a s c o n s i s t e d p r i m a r i l y of residential and
commercial waste, f o r example garbage, yard waste, paper,
plastic, metals, wood, glass and assorted rubble. The exact
types and quantities o f waste brought to the landfill in the
early years are unknown due to a lack of accurate record
keeping. I t is only from 1980 to the present that records
are available on tne waste brought to the landfill. Several
efforts have been made to estimate the t o t a l quantity of
waste present in the landfill. By using these estimates, it
is possible to work backwards from what is known now, and
make rough estimates of the acceptance rate of waste a t the
landfill i n the past. Discussions with City of Regina
employees allowed fo r the development of a map, Figure 5.1,
indicating the believed ages and locations of waste at the
landfill.
In addition to the solid waste that has been brought to the
landfill, liquid waste, including waste oil, and wastewater
sludge have a l s o been disposed of at v a r i o u s times. L i q u i d
waste was deposited at various locations on the landfill i n
pits that were 4 to 5 m in depth. This practice was stopped
because of potential groundwater contamination concerns.
Wastewater sludge was primarily deposited on the top of the
landfill and rnixed with surface material.
In addition to waste coming d i r e c t l y from generators, some
waste has corne from both a waste incinerator and a waste
shredder. An incinerator was constructed in 1951 with an
operating c a p a c i t y of approximately 5.4 tonnedhour. With an
average working day of 16 hours the incinerator could
incinerate close to 86 tonnes every day. In 1961, the
incinerator was expanded and t h e c a p a c i t y was i n c r e a s e d t o
approximately 9 tonnes/hour which meant t h a t 1 4 4 tonnes
could be incinerated every day. In the late 1960's and early
1970rç, pollution control requirements greatly reduced its
capacity. In 1975, a garbage shredder began operation with a
capacity of almost 27 tonnes/hour or 45,000 tonnedyear. The
shredder was capable of reducing the size of the waste to 75
mm in size or less. The waste shredder operated until 1986.
A summary list of the types and quantities of waste brought
to the landfill from 1980 to 1997 c m be seen i n Table 5.1.
A high percentage of waste landfilled at the Regina Fleet
Street Landfill has been rubble. There has been a decrease
over time in t h e ratio of rubble to waste landfilled, due in
part to waste diversion and recycling programs. The high
amount of rubble (asphalt and concrete), which does not
g e n e r a t e landfill gas, occupies a large volume in the
landfill and must be taken into account when using landfill
gas models or making interpretations of field data.
5 - 2 T h e Saskatoon Landfil1
The Saskatoon Landfill was opened on August 16, 1955 on l a n d
previously used f o r farming. The Saskatoon Landfill is
located i n the southwest corner of the City of Saskatoon. To
the West of t h e landfil1 is a Saskatchewan Government power
station and to the north are railway tracks. P a s t the train
tracks to t h e north lies a City of Saskatoon golf course. To
the south and east of the landfill runs the South
Saskatchewan River; this river is a primary f e a t u r e of the
City of Saska toon . A map of the Saskatoon Landfill can be
seen in Figure 5.2.
The Saskatoon Landfill is composed of a north cell, opened
in 1955 and closed in 1996, and a south ce l l , opened in
1996. The Saskatoon Landfill is the major waste disposa1
site for the City of Saskatoon and r e c e i v e s primarily
municipal and some indusirial waste. Compared to the Regina
Fleet Street L a n d f i l l , little rubb le i s landfilled due to
its use in various river bank projects. I n t h e p a s t , t h i s
site has received l i q u i d waste of various types and
q u a n t i t i e s . Waste oil was received and disposed of a t t h e
site, in separate disposal pits, up until 1980 at which time
this prac t ice was
F i g u r e 5.2 - T h e Saskatoon Landfill Study A r e a .
discontinued. Feedlot manure was also deposited at the
Saskatoon Landfill for a large number of years. The rnanure
was separated and stockpiled on the north side of the
landfill.
The Saskatoon Landfill slopes towards the South Saskatchewan
River. The top layers of material under the landfill consist
of sand, silt and clay. Below these layers lie approximately
50 m of till which overlies bedrock, silt and sand.
The north ce l l , the study area, of the landfill is
approximately 40 years old, 35 m in height, with an area of
roughly 20 hectares and a volume of approximately 3,200,900
m3. The average density of the waste is believed to be
approximately 641 kg/m3, which gives a total mass of waste
in the study area of approximately 2,000,000 tonnes
(Casavant, 1998) .
7 0
6.0 Results of the Landfill Investigations
6.1 Regina F l e e t Street L a n d f i l l Waste Sampling
Sorne on site analyses on t h e waste took place d u r i n g
sampling. The boreholes and the test pit were logged to give
an indication of the types and ages of material f o u n d at
various d e p t h s . In addition t o the borehole logs,
temperatures were also recorded, but due t o improper d a t a
collection, temperatures were not recorded for al1 d e p t h s .
Basic analysis of al1 waste samples, carried out by the SRC,
i n c l u d e d tests for chloride, sodium, organic carbon and
arnmonia as nitrogen. Other tests determined the chemical
o x y g e n demand (COD), moisture content, loss of ignition,
total dissolved solids (TDS) and pH.
D e t a i l e d analysis was conducted on a select number of
samples. A plate count was completed, which gives an
indication of the number of microorganisms present in the
waste sample and can be used as an indication of microbial
activity. The waste was also analyzed for thirty inorganic
substances including heavy metals, such as mercury and lead,
and key n u t r i e n t s , such a s phosphorus a n d potassium.
Finally, 26 organic compounds were tested for including
benzene, toluene and xylene.
The f i r s t b o r e h o l e , Borehole#l, was drilled 21.5 m i n t o t h e
landfill. The results of the basic laboratory analysis
c o n d u c t e d on the samples from B o r e h o l e # l can be found in
Table 6 . 1 .
Table 6.1 - Data f r o m t h e b a s i c laboratory analysis fo r Borehole#l.
A summary of the results for a sub-set of parameters of t h e
deta i led laboratory a n a l y s i s conducted on select samples
f rom Borehole#l can be found i n Table 6.2.
Depth
S u r f a c e 2 3 4 5 7 8 9 10 12 13 14 15 17 18 f9 20 21
Average
pH
7.99 8.24 '
8 .O6 7.93 7 -28 7 - 7 1 8.06 6.37 8.40 7.95 8-41 8.07 7-30 7-94 8.10 7.99 8-35 7 - 3 4 7.56
Moisture Content (%)
16.10 19.50 23.50 21.40 23-90 26.90 20.90 49.20 18.20 15.90 17.10 38.20 33.10 20.50 16.00 20.00 24.40 18-2 22.26
Ammonia as N i t r o g e n
( m g m 0.21 , 1.3 3.4 3.0 9.2 11
Temp. (OC)
n / a n / a n / a n / a n/a n / a
Organic Carbon (mg/L) 6.0 7.3 9.4 94 250 90
n/a n / a n / a n / a n / a n / a n / a n / a 12 1 5 17 25
17.25
3 3 1 14 65 17 46 61 38 170 49
24 11 7.3 7.2 5.9 4.9
- 5.1 5 7 34 34 n/a
55.83
3.9 6-2 2.6 n / a 6.33
Table 6.2 - Detailed laboratory analysis for select samples from Borehole#l.
- - - - -
Note: ct - count
Depth (m)
1
1 6 11 16 21
Ava .
The second borehole, Borehole#2, was drilled next to
Borehole#l and extended to a depth of 11 m. Temperature and
borehole l o g g i n g took place for Borehole#2 but laboratory
analysis was not conducted. Temperature data for Borehole#2
c a n be seen in Table 6.3.
Table 6.3 - Temperatures from Borehole#2.
Plate Count kt*/@
6300000 3400000 800000 300000 10000000 4800000
A I
10.7 17 . 6 . Average 12.88
The Test Pit was excavated to a depth of 5 rn into the
Organic Carbon bg/W
3 15 37 81 13
24.83
landfill. The results of basic laboratory analysis on the
naste from the Test Pit can be seen in Table 6 . 4 .
Ammonia as N i t r o g e n
bg/W 0.58 15 4.2 4.7 8.5 5.5
Phosphorous (mg/L)
<0.05 O. 1 ~0.05 C0.05 O. 093 CO ,069
Lead (mg/L)
O. 003 <0.002 <0.002 C0.002 0.005
Wrcury (mg/L)
0.11 ~0.05 C0.05 c0.05 C0.05
Table 6 . 4 - Data from basic laboratory analysis for the Test P i t .
6 .2 Regina F l e e t S t z e e t Landfil1 Pteliminaty Landfil1 Gas S t u d y
DePa
1 2 3 4 5
Average
The p re l i rn inary FID gas study was conducted over
approximately a one week period during the surnmer of 1997.
The study began on July 7=" and ended on July 16'". L a n d f i l l
gas samples were not collected during tirnes of high wind o r
rain, as these cond i t i ons would interfere with proper gas
collection. Al1 but 119, o r approxirnately 173, of t h e 679
potential sampling locations were sampled. A complete list
of FID results from the Regina Fleet Street Landfill can be
seen in Appendix A.
A number of samples, 31 i n total, were collected away from
planned sampling locations at locations that had high
e m i s s i o n s i d e n t i f i e d while walking between planned sampling
locations. The results of the FID gas survey can be seen in
Figure 6.1.
PH Moisture Content (%)
Temp. (OC)
9 8.7 7 . 4 10.6 11
9 . 3 4
Organic Carbon mgm 320 190 5 4 0 94 0 1230
536.67
7.36 7.26 7.1 6.73 6.09 6.91
Ammonia as Ni trogen
(mg/fi) 18 7.1 31 50 4 8
25.68
18.93 16.2 25.1 33.8 43.5
- -
- 22.92
6.3 Saskatoon Lanàfill and Regina F l e e t S t t e e t Landfill S h a l l o w Gas Well D a t a
Two s h a l l o w gas wells, a s described in Chapter 4 , were
installed a t t h e southwest and southeast corners of the
Regina Fleet Street Landfill. Four s imilar wells were
installed at the Saskatoon Landfill. The gas collected from
the wells was sent to ERMD for analysis. The gas was
analyzed for 144 substances. The results for al1 144
substances for the Regina Fleet Street Landfill can be seen
in Appendix B.
Because the impacts of al1 144 substances are not yet known,
only a srnall number are examined here. For the purposes of
cornparison between the Regina and Saskatoon Landfills, 18
substances were looked at. These 1 8 substances were chosen
because they are narned i n t h e Canadian Environmental
Protection Act (CEPA) (Canada Gazet te , Part 1, February 11,
1989) as priority substances. In addition to these priority
substances, vinyl chloride, a known toxic substance (TS),
and a nurnber of ozone d e p l e t i n g substances (ODS) were also
exarnined. The results from the Regina Fleet Street Landfill
can be seen in Table 6.5.
Table 6.5 - VOC concentrations ( p g / m 3 ) frorn shallow gas wells at the Regina Fleet Street Landfill.
I compounds SW Well (pg/m3) 1 SE ~ e l l ( p g / m 3 ) 1
Vinyl Chloride l 967 14348 I Freon 12 918 17229
Freon 22 4539 16768
Freon 113 1 15 1 1421 1
I 1
Total 1 7033 1 55466 1 Freon 114
I I P r i o r i t y Substances
5 92 1778
m/ p-Xylene
Benzene
1 1
Toluene 3259 5 4 4 3 3 1 1 I
39774
4 660
Trichloroethene
79727
2706
153 I 3272
f I
I Tetrachloroethene
1 1
t 1
Total (144 compounds) 1 446185 1302598 1
Dichloromethane
I
1 185
Total (18 compounds)
The r e s u l t s of t h e VOC t e s t i n g for the Saskatoon L a n d f i l l
can be seen in Table 6.6.
6172
I 309
66448 I 347374
% of Total
129040
I 14.9 26-3
Table 6.6 - VOC Concentrations (pg /m3) from four s h a l l o w gas wells at the Saskatoon Landfill.
Vinyl C h l o r i d e 1701 18320 164 535
Freon I I 68 744 O 69993
F reon 12 1072 17747 790 22831
Freon 22 12732 1 3 0 1 6 3713 5978
Freon 113 33 152 4 3 878
F reon 114 169 2636 208 578
To ta1 15775 52615 4918 100793 I I
P r i o r i t y Substances
O-Xylene 2012 10463 1 5 6 1323
m/p-Xylene 7697 31312 739 6022
Benzene 801 5453 9435 68 9 1 f 1 1
T r i c h l o r o e t h e n e 1869 1 220 9 i 0 1 I 162 1 1 1 1
Toluene 1 30985 ( 72928 1 485 1 79076 I I I I
T e t r a c h l o r o e t h e n e 891 6223 1 4 3 401 1 1 1 1
Dich lo rome thane I 3356 1 1366 860 1 25458
1,2,4-Trichlorobenzene O O O O
T o t a l 1 47611 130410 9458 113131
T o t a l (18 compounds) 63386 103026 14376 213924 1 f I I
Total (144 compounds) 1 390932 1 570941 1 2374075 1 880934 1 1 1 l
% of Total 16.2 1 32.1 0.61 24.3
T h e VOCs can aiso be placed in groups with cornmon attributes
for ana lys i s : freons which a r e known ozone depleting
substances; benzene, toluene, ethylbenzene and O-m-p xylenes
abbreviated as BTEX; and vinyl chloride. Concentrations of
these groups from t h e Regina Fleet Street Landfill c a n be
s e e n in Table 6.7. These sub-categories were c h o s e n because
they are the same ones examined by ERMD, thus allowing for
cornparisons t o be made.
T a b l e 6.7 - Summary of VOC c o n c e n t r a t i o n da ta from the Regina Fleet Street Landfill.
Compounds
Freons 1 0.006 1 0.041 1 0.004-0.041 1 BTEX
SW Well-Aug . 22, 1997
(g/m3)
The results from the S a s k a t o o n Landfill and previous ERMD
O. 108
Vinyl Chloride
studies for the v a r i o u s sub-categories can be seen in Table
SE Well-Aug. 22, 1997
(g/m3)
Table 6.8 - Surnmary of VOC concentration data £rom the Saskatoon Landfill.
ERMD Ranges
( d m 3 )
0.186
0.00097
0.056-0.59
I BTEX I 0.046 I C.133 I 0.018 I 0,090 I 0.056-0.59 I
0.0143
Compounds
0,001-0.041
Well#l ( d m 3 )
Freons
Vinyl Chloride
We11#2 ( d m 3 r
O. 014
0.0013
WellQ3 (da3 r
0.034
0,018
Wellf 4 ( d m 3 I
0.005
0 00016
ERMD Ehnges ( d m 3 )
O. 100
0-00054
0.004-0,041
0.001-0.041
6 . 4 R e g i n a F l e e t S t r e e t Landfill Gas Modeling Results
The LAEEM was used to model the amount of landfill gas being
generated from the Regina Fleet Street Landfill. The
modeling was done to help validate the field data and vice
versa .
The model was run a number of tirnes with different input
parameter values. The parameters that were changed in the
various simulations were the values of k and L,, the waste
in place value for 1997, and the ratio of rnethane to carbon
dioxide in the landfill gas. The remaining parameters
remained the same for al1 of the simuLations.
The waste acceptance rates o v e r the period 1981 to 1997 were
known from landfill records and can be seen in Table 6.9.
The waste acceptance rates for the years prior to 1981 were
estlmated by subtracting the total accepted waste for 1981
to 1997 from the estimated waste in place in 1997 to get the
waste in place for 1980. Due to the uncertainty of certain
data, two estimates were made of the waste in place i n 1997,
6.5 million tomes and 7 million tonnes. The estimate of 7
million tonnes is believed to be more accurate based on p a s t
acceptance rates and landfill surveys. The estirnate for the
waste in place for 1980 allowed t h e LAEEM t o automatically
calculate the amount of waste accepted in the years from
1961 to 1980.
Table 6 .9 : Amounts of waste landfilled from 1 9 8 1 t o 1997IReid Crowther & Partners, 1995; and landfill commodity reports).
The final landfill capacity had to be estimated in orde r to
Y e a r
1981 1982 1983 1984 1985
determine the l i f e span of the landfill. This estimate was
based on the final landfill design proposed by Reid Crowther
Tomes of Rubble Landfilled
101481 124414 100488 94750 74000
& Partners Ltd. (1995), and a two hi11 landfill, the design
favored by the City of Regina. Futu re landfill acceptance
231961 244116 214073 206262 181767 174418 159001 146631 144032 14 1772 149568 175197
3375658
Tonnes of Garbage Landfilleci
132076 135440 150275 141690 15224 6
2
ra tes were assumed to remain r e l a t i v e l y constant. These
Total Tonnes Landfilled
233557 259854 250763 236440 226246
assumptions allow f o r a final landfill capacity of 9,006,000
1986 1987 1988 1989 1990 1991 1992 1993 19 94 1995 1996 1997
Total
tonnes.
83313 92258 71721 59727 44975 45542 38682 21033 15652 13803 20691 35818
1038348
148648 151858 142352 146535 136792 128876 120319 125598 128380 127969 128877 139379
2337310
The two key parameters that varied between simulations were
k and La. Both of the LAEEM default settings, CAA for arid
conditions and AP-42 for arid conditions, were used in
various simulations. The CAA default setting, k=0.02 l/year
and L,=170 ~n~/~ear, were used to examine emissions from a
regulatory perspective to determine if landfill gas control
measures would be required for the Regina Fleet Street
Landfiil based on U.S. EPA regulations. The AP-42 default
settings, k=O .O2 l/year and Lo=lOO m3/year, were used to
provide a more accurate estimate of emissions. The final set
of k and L, values, k=0 .O06 l/year and L,=170 m3/year, were
obtained from an Environment Canada report for rnodeling
landfills in Canada (Environment Canada, 1 9 9 7 a ) . The tables
containing the Environment Canada values of k and La for a l 1
the provinces in Canada can be seen in Appendix C.
The f i n a l parameter that varied between simulations was the
volumetric ratio of methane to carbon dioxide. The LAEEM
assumes a ratio for methane to carbon dioxide of 5 0 ~ 5 0 . The
Regina Fleet Street Landfill field data showed a ratio of
methane to carbon dioxide of 4 1 5 9 , which is most likely a
transitional ratio and will likely reach 50:SO over time.
Both ratios were used in various simulations.
The default parameters and the assumptions used in running
the various simulations can be seen in Table 6.10.
Table 6.10 - Parameters and assumptions used in landfill gas simulations.
D e f a u l t Parameters
CAA Defaul t ( A r i d ) L o = 170 m3/year k = 0.02 l / y e a r
AP-42 Defaul t ( A r i d ) Lo = 100 m3/year k = 0 .02 I / y e a r
Env. Canada Defaul t
Waste In Place i n 1997
6 .5 Mi l l i on Tonnes
6.5 Mi l l i on Tonnes
k = 0.006 l/;ear CAA Defau l t (Ar id )
R a t i o of CH, to CO2 in
Landfil1 Cas b CH4 = 50 cf CO2 = 50
1 CH4 = 50 S CO- = 50
6.5 Mi l l i on Tonnes
L o = 270 m3/year k = 0.02 l / y e a r
AP-42 Defaul t ( A r i d ) Lo = 100 m3/year k = 0 .02 I/year
Fnv. Canada Defaul t Lo = 170 m3/year K = 0.006 l / y e a r
CAA Defaul t (Arid) Lo = 170 m3/year
% CH4 = 50
6.5 Mi l l i on Tonnes
k = 0.02 l / y e a r AP-42 Defau l t (Ar id )
Lo = 100 m3/year
% CH4 = 4 1
6 . 5 Mil l i on Tonnes
6.5 Mi l l i on Tonnes
7 Mi l l i on Tonnes
k = 0 .02 l/year Env. Canada Defaul t
The results from the various simulations can be seen in
Table 6.11.
Ir CO2 = 59
a CH4 = 4 1 Cs CO2 = 59
8 CH4 = 4 1 8 CO2 = 59
%CH4 = 50 % C O 7 = 50
7 Mi l l i on Tonnes
7 Mi l l i on Tonnes 1 I
S CH4 = 50 Lo = 170 m3/year k = 0.006 l / y e a r CAA Default ( F z i d ) Lo = 170 m3/year k = 0.02 l/year
?iP-42 Default(Arid) Lo = 100 m3/year k = 0.02 l/year
Env. Canada Defaul t Lo = 170 m3/year k = 0.006 l/vear
% CH4 = 50 % CO2 = 50
7 Mi l l i on Tonnes
7 Mi l l i on Tonnes
7 Mi l l i on Tonnes
% CO2 = 50
B CH4 = 4 1 % CO2 = 59
8 CH, = 41 % CO7 = 59
% CH, = 4 1 % CO2 = 59
Table 6.11 - Results of landfill gas modeling.
1 Simulation # 1 Methane 1 Catbon Dioxide (
6 . 5 Saskatoon Landfill and R e g i n a Fleet S t r e e t Lanüfill Detailed Gas Study
A total of 230 emission samples were t a k e n at t h e Saska toon
L a n d f i l l over t h e surface of the n o r t h ce l l u s i n g a f l u x
chamber. The sampling was completed dusing the late
summer/early fa11 of 1997. A map showing the sampling
locations and the results of the emissions sampling can
seen in Appendix D.
The locations and quantities of methane and carbon dioxide
emissions f r o m the Saskatoon Landfill can be s e e n in Figures
6.2 and 6.3,
A summary of the c o l l e c t e d data concerning t h e quantity and
composition of the gas emitted from t h e Saskatoon L a n d f i l l
can be seen i n T a b l e 6 . 1 2 . The yearly emission rate for the
Saskatoon L a n d f i l l was c a l c u l a t e d b y assuming that the t o t a l
ernission ra te , determined at the tirne o f testing, was a n
average f o r t h e ent i re year.
Table 6 . 1 2 - Data from the Saskatoon L a n d f i l l Gas Study.
Component
Methane
Information on the maximum, minimum and a v e r a g e emissions
found a t the Saskatoon L a n d f i l l can be s e e n in Table 6.13.
Emission Rate (L/hom)
I 1 I
Table 6.13 - Emission rates from the Saskatoon L a n d f i l l Gas Study.
591663.75
Carbon Dioxide
1 Cornponant 1 Murinium Emission 1 Maximum Emissaon 1 Averaue Emission 1
Composition of Landfill Gas, 8
Annual Landfill Gas Release
37.5
985406.25
( tonnes/year) 3176
62.5
1 Rate (~/hour/m')
15146
Rate Whour/m2) 210.7 Methane
I
Rata <~/hour/m') 2.7 O
180.1 Csrbon Dioxide 4.6 0.2
A t the Regina Fleet Street Landfill a total of 675 emission
samples were taken covering 63.2 ha of the landfill site. A
flux chamber was used to collect landfill gas samples. The
samples were taken during the summer of 1997 beginning on
August 19 and ending on September 5. A table containing the
complete list of collected data can be seen in Appendix E.
Maps showing the locations of methane and carbon dioxide
emissions can be seen in Figures 6.4 and 6.5.
fnformation on the quantity and composition of the gas
released from the Regina Fleet Street Landfill can be seen
in Table 6.14. The year ly ernission rate for the Regina Fleet
Street Landfill was calculated by assuming that the total
emission ra te , determined at the time of testing, was an
average for the entire year.
Table 6.14 - Data from the Regina Fleet Street Landfill Gas Study.
Component
Methane
Emission Rate (L/hou)
Carbon Dioxide
1536975
Composition of L a n d f i l 1 Gas, %
Annual L a n d f i l l Gas W e a s e
41.5
34353 I
(tomes/year) 8842
2174850 58.5
F i g u r e 6.4 - Methane emissions a t the Regina Fleet Street Landfill (Original in co lor ) .
Table 6.15 shows additional information on the minimum,
maximum and average emissions from the Regina F l e e t Street
Landfill.
Table 6 . 1 5 - Emission r a t e s from t h e Regina Fleet S t r e e t L a n d f i l l Gas S t u d y .
1 Componen t 1 Minimum Emission 1 Maximum Emission 1 Average Emission
Methane
Carbon Dioxide
R a t e (~/hour/m') O. O
O. O
Rate Whour/m2) 198.24
Rate (~/hour/m') 2.53
130.82 3.58
7 . 0 Discussion of Landfill Investigation Resul ts
7.1 Interna1 Landfill Conditions
D a t a from two boreholes and a test pit indicate how well
Regina Fleet Street Landfill conditions reflect what is
deemed optimal for landfill gas generation. In terms of pH,
where the optimal range is 6.8 to 7.4 (Barlaz et al., 1990),
the average from Borehole#l was 7.5 and £rom the Test Pit
was 6.9. The pH from the Test Fit was in the optimal range
for landfill gas generation and should not hinder its
generation. The pH from Borehole#l is close to the average
for landfills in the later stages of landfill gas generation
(Barlaz et al., 1990) .
The temperature averages for the Regina Fleet Street
Landfill were well outside of the optimal ranges of 32 to
3 5 a ~ or 45 to 50°c (El-Fade1 et al., 1996) for landfill gas
generation. The temperatures at shallow depths averaged
12.g0c for Borehole#2 and only 9.3OC for the Test Fit.
Temperatures taken closer to the surface of the landfill are
more sensitive to atmospheric temperatures, and t h e samples
were collected in early winter. Even at greater depths in
Borehole#l. below 20 rn, the temperatures averaged only
17.3OC. Since temperatures were taken once the waste had
been removed from the borehole the recorded temperatures m a y
have been slightly lowered due to ambient conditions.
Temperature m a y be p i a y i n g a very important role in the rate
of landfill gas generation. Because low temperatures are
experienced for extended periods of tirne i n Regina, l a n d f i l l
gas generation may be lower during these months,
particularly in the upper parts of the landfill that are
most affected by atmospheric temperature changes. Emissions
will also be reduced during these months due to frozen s o i 1
conditions. This w i l l lower the total yearly generation and
emission rates. Because the analysis used summer emissions
as the b a s i s for a yearly emission or generation rate
estimate, the yearly rate m a y have been overestimated.
It has been stated earlier that the rate of landfill gas
generation increases significantly as the moisture c o n t e n t
reaches field capacity, 45 to 60% (Environment Canada,
1991), and then increases slightly as the moisture content
increases to 80% (Gardner and P r o b e r t , 1992; Munasinghe and
Atwater, 1985). The m a j o r l t y of l a n d f i l l s i n N o r t h America
average between 20% and 30% at t h e time of placement
(Gardner and P r o b e r t , 1992) . The Regina Flee t Street
Landfill, based on samples from one borehole, had an average
moisture content of approximately 22%. The low moisture
content is not surprising considering the very dry
conditions present in the Regina a r e a . The low moisture
content will reduce the rate a t w h i c h landfill gas will be
produced ,
In addition to moisture content, pH and temperature, there
are optirnal l eve l s for nutrients and other chemicals for
landfill gas generation. One of the key nutrient factors is
the carbonhitrogen ratio in the waste. In most landfills,
this ratio is 30:l (Gardner and Probert, 1992); in this
landfill, it was 21:l in the Test Pit, but only 9:l in
Borehole#l. Low ratios could indicate lower rates of
landfill gas generation at the Regina Fleet Street Landfill.
Low ratios could also indicate that waste decomposition has
occurred in the older sections of the landfill.
The results of the plate count tests indicate that there
were greater numbers of microorganisms in the landfill near
the t op and bottom. The presence of microorganisms at a l 1
leveis tested indicates that, even though some of the
landfill conditions are outside of optimal ranges, microbial
activity is caking place, landfill gas is being generated,
and the waste is being broken down, The fact that the
samples were t a k e n from an older portion of the landfill
could explain the pattern of microbe counts. The waste may
not have h a d sufficient quantities of nutrients to support
large numbers of microbes. The upper portions, the newer
waste, may have sufficient nutrients available for microbial
activity, hence t h e higher numbers of microbes. N u t r i e n t s
would t end t o be leached from upper parts of the landfifl
and accumulate in lower areas providing sufficient nutrients
for the microbes found t h e r e .
The moisture content of the l a n d f i l l waste could be
increased by increasing infiltration thxough the cover,
decreasing r u n - o f f , or by adding moisture t o the landfill. A
higher moisture content would increase decomposition,
landfill s e t t l i n g and landfill gas g e n e r a t i o n rates a t the
Regina Fleet Street Landfill. However, higher moisture
contents would also increase the potential for leachate
g e n e r a t i o n that could pose a risk to the local aquifers.
7 . 2 Combustible Vapour Concentrations
T h e m a j o r i t y of points sampled with the FID had low
concentrations. The few points that had high concentrations
were l o c a t e d primarily along t h e slopes of the landfill,
particularly the south and east slopes. The south slope had
the highest number of high concentration points and had the
highest individual FID readings. Very low concentrations
were found in areas that were w e l l compacted. The compacted
soi1 may have operated a s a barrier to lanàfill gas
emissions.
There were a number of visual observations made while
collecting the preliminary landfill gas samples. Locations
exhibiting high FID readings on the south slope were
generally marked by missing or dead vegetation indicating
the presence of landfill gas. Also, a majority of the
locations along the south slope with high FID readings were
located at or near large cracks in the landfill surface
which may have facilitated the emission of landfill gases.
Visual observations were only possible along the south slope
due to the presence of vegetation and the lack of landfill
activities on that slope which would have removed signs of
landfill gas emissions.
T h e data showed a high degree of variability in terms of
concentration levels between points, as illustrateci in
Figure 7.1. Concentration leveis at a few points far
exceeded the concentrations at other surrounding points.
Approximately 16% of the sampling points had concentrations
less than or equal to 1 ppm. It appears that landfill gas is
being channeled from large areas within the landfill to a
small number of points where it is emitted.
A - - - - - - -- - - > = - A
FID Readings vs. Collected Samples
Collected Samples
Figure 7.1 - Variablity in FID readings.
A r e l a t i v e l y small p e r c e n t a g e of concentration points, 3%,
accounted for 63% o f t h e total amount of combustible vapour
found, as shown i n Figure 7 . 2 .
% of Combustible Vapour From Points with Greater Than 100 PPM of Combustible Vapour
% of Combustible Vapour From 3% of the points with the Hgkst Concentrations
0 % of Combustible Vapour From Remaining 97% of Points
Figure 7.2 - Combustible vapour from the highest concentration points.
P o i n t s w i t h h i g h l a n d f i l l gas concentrations were not
necessarily surrounded by other points of high
concentrations. Concentrations seemed to be highly confined
to s p e c i f i c locations at the landfill.
Because the combustible vapour, and presumably the landfill
gas, concentrations were concentrated along the slopes, the
detailed landfill gas sampling was concentrated on the
slopes of the landfill. Fewer sarnples were taken along the
top of the landfill, which showed uniformly low EID readings
during the preliminary study.
7.3 VOC Concentrations
The results of VOC testing from other landfills in Canada,
a s provided b y ERMD, can be compared to the results from the
Regina and Saskatoon Landfills to give an indication of the
r e l a t i v e concentration levels. The reported BTEX
concentrations, as measured by EMRD (Environment Canada,
1997b), at a number of Ontario landfills were in the range
of 0.056 g/m3 to 0.59 g/m3. The concentrations a t the Regina
Flee t Street Landfill ranged from 0.108 g/m3 to 0.189 g /m3,
and at the Saskatoon Landfill t h e range was 0.018 g/m3 to
0.133 g/m3. The r e s u l t s from the two Saskatchewan l a n d f i l l s
ind icé i t e t h a t t h e levels for BTEX were in the low to m i d d l e
range based o n ERMD d a t a .
The measurements of vinyl chloride concentrations at Ontario
landfills studied by ERMD range from 0.001 g /m3 to 0.041
g/m3. The levels reported at the Regina Fleet Street
Landfill were 0.001 g/m3 (SW Well) and 0.014 9/m3 (SE Well) ,
and at the Saskatoon Landfill the range was 0.001 g/m3 to
0.018 g/m'. The vinyl chloride levels at both of the
Saskatchewan landfills were in the low to middle range based
on ERMD data.
The levels of freons reported by ERMD (Environment Canada,
1997b) at Ontario landfills were in t h e range of 0.004 g/m3
to 0.041 g / m 3 . The range of freons at the Regina Fleet
Street Landfill was 0.006 g /m3 to 0.041 g / m i and at the
Saskatoon Landfill the range was 0.005 g/m3 to 0.100 9/m3.
The freon levels reported at the Regina Fleet Street
Landfill span the total range of l e v e l s for a number of
landfills in Ontario and show a large degree of variance
between the southwest and southeast wells. The Saskatoon
Landfill had freon concentrations in one well that were more
t han double that reported at the R e g i n a Fleet Street
Landflll and at the Ontario landfills,
There are no specific regulations dealing with VOC emissions
from landfills in Canada. There are, however, limits set in
the Occupational Health and Safety Act (OHSA) for exposure
to various contaminants by workers. Two VOC concentrations
from the Regina Fleet Street Landfill and the Saskatoon
Landfill exceeded the limits set by OHSA; both happen to be
known carcinogens. Vinyl chloride concentrations at one w e l l
at each landfill, 14 mg/m3 at the Regina Landfill and 18
mg/m3 at the Saskatoon Landfill, exceeded the 10 mg/m3 OHSA
limit. Benzene levels exceeded the 0.300 mg/m3 OHSA limit at
al1 wells at both landfills and in some cases significantly
exceeded the limits, 4.6 and 2.7 mg/m3 a t the Regina
Landfill and 5 .4 and 6.4 mg/m3 at the Saskatoon Landfill.
The limits set by the OHSA are for an average exposure to
those contaminants for a typical 8 hour work day. While the
VOCs emitted from the landfill would be quickly diluted to
low levels upon reaching the surface, they may pose a risk
if landfill gas migrates to enclosed spaces on or off site
or if workers are exposed to direct emissions from the
landf ill.
While the levels reported at the Regina and Saskatoon
Landfills may appear high or l o w for various compounds, a
very small number of samples were obtained. For a small
sample set, there tends to be a higher degree of variance
between sampling l o c a t i o n s . A l so , a s i n g l e r e a d i n g c a n have
a l a r g e impac t o n the r e s u l t s . F o r example, the f r e o n l e v e l s
a t t h e two Saska tchewan l a n d f i l l s appear h i g h . The high
f r e o n r e a d i n g s c o u l d be due t o a number of i n f l u e n c i n g
f a c t o r s a t these p a r t i c u l a r l o c a t i o n s i n c l u d i n g t h e
d i s p o s a l , i n the area of t h e w e l l , of a s i n g l e source o f
f r e o n , such as any t y p e of c o o l i n g equipment . The f r e o n
l e v e l s would o n l y be a n a r e a o f concern i f s u b s e q u e n t
s amples a t o t h e r l o c a t i o n s a l s o show h i g h freon l e v e l s . I n
o r d e r t o d e t e r m i n e a more r e p r e s e n t a t i v e a v e r a g e for VOCs
from the Regina and Saska toon L a n d f i l l s , sampl ing from a
v a r i e t y o f d i f f e r e n t l o c a t i o n s a t t h e two l a n d f i l l s i s
r e q u i r e d .
7 . 4 Estimated Landfill Gas Generation Rate
Due t o a l a c k o f precise i n p u t d a t a , sorne mode l ing e r r o r is
t o b e e x p e c t e d . A s s t a t e d earlier e r r o r s o f k20 t o 30%
(Gardne r and P r o b e r t , 1992 ; Z i son , 1990) of a c t u a l values
a r e commonly found when s i m u l a t i o n s are c o n d u c t e d o n
l a n d f i l l s w i t h less t h a n perfect d a t a .
T h e mode1 s i m u l a t i o n of t h e Regina Landfill that most
closely matched t h e field s t u d y results of 8842 t o n n e s / y e a r
o f methane and 3 4 , 3 5 3 t o n n e d y e a r of carbon d i o x i d e , was
simulation lb, w i t h estimates of 11,170 tonnes/year of
methane and 30,650 tonnedyear of carbon dioxide. This
simulation was within 21% of the field study methane
emissions and 10% of the caxbon dioxide emission. This level
of error is similar to what has been reported for other
studies. It is also similar to the 10 to 15% error reported
by Saskatoon engineers in modeling their landfill (Casavant,
1998). The difference between the simulation results and the
actual field data is likely due to the LAEEM limitations,
and errors in the field results. Also, the LAEEM is designed
to estimate the amount of landfill gas generated within the
landfill while the field study measured landfill gas
emissions.
The CAA defaults, for arid c o n d i t i o n s , more closely
approximated the field results. The AP-42 default settings
use a lower L,. The low L, would tend to reduce the amount
of landfill gas t h a t would be generated by a given quantity
of waste, thereby lowering the amount of landfill gas
generated for a given landfill. As for the default values
specified by Environment Canada, the k value is much lower
than the one recornrnended by the U.S. EPA. T h e effect of the
low k value would be to lower the amount of landfill gas
that would be generated within a given landfill. In
addition, a summer generation and emission rate estimate was
a p p l i e d over the whole year , making the f i e l d results
perhaps more representative of maximum expected emissions.
As more data are collected on the landfill, the LAEEM
simulations c a n be further refined over time. T h e d e f a u l t
v a l u e s suggested i n t h e LAEEM for arid conditions appear to
be s u i t a b l e f o r simulating Saskatchewan landfills. However,
because there is a significant range of possible k and L,
default values, it is not known which ones will most
accurately mode1 Saskatchewan landfills. Various methods,
s u c h as U.S. EPA Method 2E or addltional emission studies,
can be used t o determine site specific values of these
v a r i a b l e s .
7 . 5 Spatial Variability
7.5.1 T h e Saskatoon Landfill
The emissions from the Saskatoon Landfill showed a high
degree of spatial v a r i a b i l i t y , The highest carbon dioxide
emission rate, 1 8 0 ~ / h o u r / m ~ , was more than d o u b l e the next
highest emission rate, 81.3 ~/hour /m* . For methane
emissions, the highest emission r a t e , 210 ~ /hour /m ' . was
more than t r i p l e t h e next highest recorded emission rate, 69
~ / h o u r / m ~ . A large number of locations'at the landfill
showed v e r y low e rn i s s ions , while o n l y a few a r e a s were
responsible f o r the m a j o r i t y of the total measured
e m i s s i o n s . The high o b s e r v e d emissions at a few l o c a t i o n s
c o u p l e d w i t h the low e m i s s i o n s a t t h e majority o f l o c a t i o n s
i n d i c a t e s t h a t v e n t i n g a t c e r t a i n l o c a t h n s on t h e l a n d f i l l
s u r f a c e was t a k i n g p l a c e .
T h e h i g h e rn i s s ions a t t h e Saska toon L a n d f i l l o c c u r r e d a l m o s t
e x c l u s i v e l y a l o n g t h e t o p p o r t i o n o f t h e s l o p e s o f t h e
l a n d f i l l . Only one l o c a t i o n of h i g h emissions was r e c o r d e d
away £rom t h e l a n d f i l l slopes. T h i s c o u l d be c a u s e d by t h e
g r e a t e r quantity and g r e a t e r compact ion of t h e c o v e r
m a t e r i a l t h a t would o c c u r on t h e top o f t h e l a n d f i l l .
L a n d f i l l gas, which would t e n d t o m i g r a t e v e r t i c a l l y , may b e
f o r c e d t o m i g r a t e h o r i z o n t a l l y u n t i l i t reaches a n a r e a
where i t can e s c a p e .
Carbon dioxide e m i s s i o n s over the surface of the S a s k a t o o n
L a n d f i l l were h i g h e r than methane emissions at t h e same
l o c a t i o n s . Because of t h e age o f t h e waste i n the l a n d f i l l ,
a c a r b o n d i u x i d e t o methane r a t i o close t o 50:50 would be
expected (McBean et a l . , 1 9 9 5 ) . The h i g h e r q u a n t i t y o f
c a r b o n dioxide found c o u l d be p a r t i a l l y d u e t o t h e o x i d a t i o n
of methane and other l a n d f i l l g a s e s a t the surface due to
the microbes present there. One of the by-products of this
consumption is carbon dioxide (Hettiaratchi, et al., 1996).
7 . 5 . 2 The Regina F l e e t Street Lanàfill
The spatial variability found at the Saskatoon Landfill is
similar to what was found at the Regina Fleet Street
Landfill. The detailed field investigation found highly
variable emissions across the entire landfill surface for
both methane and carbon dioxide. Variability was expected
due to the high degree of variability found during t h e
preliminary gas investigation. The degree of variability was
somewhat surprising in that the highest point emissions were
in some cases up to 80 times the landfill average. For
example, the highest methane ernission rate was 198 ~/hour/m~
while the landfill average for methane was only 2.53
~/hour/m'. And in the case of carbon dioxide, the h i g h e s t
emission rate was 103 ~/hour/rn', while the landfill average
was only 3.58 ~/hour/m'. Gas emissions in the detailed study
were concentrated along the slopes of the landfill, as found
in the preliminary study and at the Saskatoon Landfill. The
slopes accounted for the rnajority of emissions from the
Regina Fleet Street Landfill. The south, north and east
slopes combined to release more than 60% of the total carbon
dioxide and more than 70% of the total methane emissions
measured over the entire landfill. The emission patterns rnay
indicate problems with the integrity of the interim cover at
those locations. To better control emissions from both
landfills, additional cover material, or a collection and
control system may be needed along the slopes.
The south slope, which exhibited the highest concentrations
during the preliminary study also showed high point
emissions d u r i n g the detailed study. However, what was not
apparent during the preliminary study was that aside from
several points of very high emissions, the overall emissions
for the s o u t h slope were very low. The average gas emissions
on the south slope were only 2.13 I,/hour/rn2 for carbon
dioxide and 0.82 ~/hour/rn' for methane. Areas surrounding
points of high emission did not show similar high emissions.
The low emissions from the south slope can be partially
explained by examining the waste under this slope. The waste
under the south slope is some of the oldest at the landfill
with the majority dating back to the opening of the
landfill. It is known from past studies (Gardner and
Probert, 1992) that most waste reaches peak gas generation 3
to 15 years a f t e r being landfilled. The waste under the
south slope is probably past its peak generation period. The
high point source emissions along the south slope were not
likely due to high gas generation under the s o u t h slope, but
probably due to venting from other areas with a more
impermeable landfill cover.
W h i l e t h e highest point source methane emissions were found
along t h e south slope, the area showing the highest
concentration of methane emissions was the top half of the
e a s t slope, The e a s t slope had an average methane emission
r a t e of 6.47 ~/hour/m', which was close to 2.5 times t h e
average methane emission rate for the landfill- The e a s t
slope also had a carbon dioxide ernission rate of 7.39
~/hour/m', which was 2 times the landfill average. From
Figure 5 . 1 , it can be s e e n that t h e waste under t h e east
slope was deposited from 1989 to 1 9 9 3 . B e c a u s e the waste is
from 5 to 9 years old, it is in the early stages of peak
I m d f i l l gas generation (Gardner and Probert , 1992). T h i s
stage i s characterized by a leveling off of c a r b o n dioxide
emissions and increasing generation of methane. The ratio of
methane to carbon dioxide was close to 5 0 ~ 5 0 as would be
expected from waste of this age. It can be expected that as
the waste cont inues to age it will begin to produce greater
volumes of methane.
Whi le t h e h i g h e s t c o n c e n t r a t i o n o f methane was along t h e
n o r t h e r n p o r t i o n of t h e east s l o p e , t h e h i g h e s t emissions of
carbon d i o x i d e were f o u n d a long t h e n o r t h slope. T h e c a r b o n
d i o x i d e e rn i s s ion r a t e from t h e n o r t h d o p e averaged 9 . 3 7
~/hour/m', w h i c h was a p p r o x i m a t e l y 2 . 6 tirnes t h e l a n d f i l l
average. The methane exnission r a t e f rom t h e n o r t h s lope was
3 -54 ~ / h o u r / m ~ , which w a s o n l y 1 . 4 times t h e l a n d f i l l
average. The w a s t e under the n o r t h s lope was l a n d f i l l e d f r o m
1995 t o 1 9 9 6 . The w a s t e under t h e n o r t h s l o p e was i n the
v e r y e a r l y stages o f l a n d f i l l gas g e n e r a t i o n ( G a r d n e r and
Probe r t , 1 9 9 2 ) . The early stages of gas g e n e r a t i o n are
c h a x a c t e r i z e d by a high r a t i o o f carbon d i o x i d e t o methane
being generated. A s t h e waste ages, it will b e g i n t o show
emission p a t t e r n s s i m i l a r t o what was found on t h e east
s lope . Carbon d i o x i d e generation w i l l b e g i n t o d e c r e a s e a n d
me thane g e n e r a t i o n w i l l increase a s t h e waste a g e s , and as
methanogenic rnicroorganisrns become more prevalent.
The lack of e m i s s i o n s from t h e w e s t s l o p e coulci be d u e t o
s e v e r a l factors. F i r s t l y , the waste under the west s l o p e is
sorne o f the oldest waste and iç l i k e l y l ong p a s t i t s time o f
p e a k gas g e n e r a t i o n . I n addition, b e c a u s e the waste is
o l d e r , it may con ta in a higher percentage o f rubble than
o t h e r areas due t o d i f f e r e n t landfilling practices i n t h e
past. Additionally, because rnost o f t h e r o a d s around t h e
Landfill originate on the west slope, it is highly compacted
rnaking gas emission on that slope very d i f f i c u l t . Any gas
t h a t is generated under the west slope may be forced to
migrate away from there to other locations for emission.
T h e low l e v e l of emissions frorn the top of the landfill is
believed to be primarily due to the d i f f i c u l t y faced by
l a n d f i l l gas migrating through numerous l ayers of cover
material and w a s t e . Also, the large amount of heavy traffic
on t h e surface of the landfill compacts the surface and
restricts gas emissions .
7 . 6 Emission Rates
The emissions from the Regina Fleet Street Landfill,
3,711,525 L/hour, were greater in total t h a n the Saskatoon
emissions, 1,577,069 L/hour. This is d u e to t h e much l a r g e r
amount of waste present in the Regina study area, 7 million
tonnes, versus 2 million tonnes in the Saskatoon study area.
If an emission rate per unit of waste is examined, the
Regina Fleet Street Landfill was actually emitting less gas
per unit of waste than the Saskatoon Landfill: 4 - 6 5
m3/ tonnedyea r as compared to 6.6 m'/t~nnes/~ear. However,
there is a large amount of rubble, which does not generate
landfill gas, in t h e Regina Fleet Street Landfill. If
r u b b l e , assumed at 30% by volume, were excluded from the
Regina waste totals, t h e n the emission per unit of waste at
the Regina Fleet Street Landfill was 6 -65 m3/tonnes/year.
Since only two landfill gas surveys have been completed in
Saskatchewan, it is difficult to determine the validity of
the data collected from either landfill. In order to
determine if the results of these studies are valid, a
comparison must be made with the results from other landfill
gas studies. The majority of landfill studies state landfill
gas generation in terms of a rate per unit of waste per
year, which allows comparisons to be made between landfills
of differing sizes.
Cornparisons were made between the Regina Fleet Street and 1
Saskatoon Landfill emissions, and generation rate estimates
from other studies. A report by the U.S. EPA stated that
landfill gas emissions varied from 1 to 8 m%~nnes/~ear
(Pohland and Harper, 1987) at observed landfills. Another
report stated that gas emissions at studied landfills have
varied from 3 to 40 m3/tonnes/year (Environment Canada,
1 9 9 5 ) . One source stated gas emission variance £rom numerous
literature sources of 0.059 to 400 ~n~/tonnes/~ear (McBean et
al., 1995). F i v e landfills in Canada and the United States
had landfill gas emission in the range of 2.6 to 9
m)/t~nnes/~ear (Gardner and Probert, 1992) . An additional study observed emissions of 0.34 to 68 m3/tonnedyear
(Barlaz et al,, 1990) a t a large number of landfills in the
United S t a t e s .
The emissions in Regina are in the low to middle range based
on literature data. In addition to the pxesence of large
amounts of rubble, fower emission rates from the Regina
Fleet Street Landfill are to be expected when severa l
factors are taken into account. The temperatures and
moisture contents in the landfill waste samples were far
below what is necessary for optimal landfill gas generation.
The Saskatoon Landfill also f a l l s in the lower to middle
range of recorded emissions. It can be assumed that the
landfill conditions in the Saskatoon Landfill are similar to
the conditions in the Regina Fleet Street Landfill.
7 . 7 LandfiII Gas ControI Considerations
There currently exists no legislation in the province of
Saskatchewan specifically addressing landfill gas emissions,
and their control or utilization. British Columbia has
legislation primarily based on the U.S. €PA guidelines for
L a n d f i l l gas e m i s s i o n s . O n t a r i o a n d Quebec also have more
general regulations addressing l a n d f i l l gas e m i s s i o n s .
The U.S. EPA g u i d e l i n e s on landfill gas emissions are based
on two f a c t o r s : landfill size and Non-Methane Organic Carbon
(NMOC) emissions. If both of these f a c t o r s are met, control
measures are r e q u i r e d . Control measure are only required for
landfills exceeding 2.5 million tonnes in final s i z e which
are emitting 50 t o n n e d y e a r or more of NMOCs. The
r e g u l a t i o n s in British Columbia require c o n t r o l measures at
landfills exceeding 100,000 tonnes of c a p a c i t y and emitting
1 5 0 t o n n e s / y e a r of NMOCs.
With a current s i z e of close t o 7 m i l l i o n tonnes and
e s t i m a t e d NMOC e m i s s i o n s from LAEEM s i m u l a t i o n s ranging from
181 to 4 8 0 t o n n e d y e a r , t h e Regina Fleet S t r e e t Landfill
would be required t o control l a n d f i l l gas emissions i f it
were located i n e i t h e r o f those jurisdictions. The U.S. EPA
and t h e B r i t i s h Columbia government l e a v e the method of
c o n t r o l up t o t h e r e s p e c t i v e l a n d f i l l operator but e n c o u r a g e
landfil1 gas u t i l i z a t i o n if possible.
While the Regina Fleet Street L a n d f i l l may have sufficient
size t o g e n e r a t e usable quantities of gas, the less than
o p t i m a l conditions, p a r t i c u l a r l y low m o i s t u r e content, would
lower generation rates. Because of this, f l a r i n g to control
both methane emissions and VOC emissions may be the b e s t
option.
8.0 Summary, Conclusions and Reconimendations
8.1 Summary and Conclusions
Field investigations and modeling studies were completed for
two semi-axid landfills in Saskatchewan. This research
sesulted in information on the level and pattern of
ernissions, and the landfill gas generation potential and
r i s k s at the studied sites.
Interna1 landfill conditions at the Regina Fleet Street
Landfill suggest that landfill gas generation is occurring,
but at a lower rate than optimal. The pH level found in the
waste was very close to the optimum for landfill gas
generation and shouid not hinder landfill gas generation.
The carbonhitrogen ratio was lower than what would be
required for optimal landfill gas generation but not
significantly lower. Microbial activity was indicated
throughout all layers of the landfill, suggesting that even
though l a n d f i l l conditions rnay not be optimal waste
deconposition is still taking place.
The f a c t o r s that would tend to have the greatest impact on
l a n d f i l l gas generation are temperature and moisture
content. The moisture content in the Regina Fleet Street
Landfill was significantly lower, up to 6O%, than what would
be required for optimal landfill gas generation. The
temperature readings were significantly lower, up to lg°C
lower, than what is deemed optimal for landfill gas
generation. In addition to affecting the amount of landfill
gas generated, interna1 temperatures would also affect the
validity of the estimate made for the total yearly landfill
gas emissions, A summer emission rate estimate was used as
the basis for a yearly rate. A c t u a l l a n d f i l l gas production
and emissions would be expected to be lower than the field
study estirnate.
The field investigations provided an indication of the
suitability of various landfill gas field measuring
equipment. The FID study indicated a high degree of
combustible vapour on t h e south and east s l o p e s of the
l a n d f i l l . The detailed flux chamber study l a t e r confirmed
high emissions on the east slope but did not find high
emissions over the south slope. The FID study also f a i l e d to
àetect t h e h i g h emissions later found on the north slope,
The east slope had a higher amount of methane ernitted than
the north slope. Since methane is a combustible vapour, its
presence in higher quantities could e x p l a i n FID emissions
being found on the east slope and not the north slope. The
FID study did prove very u s e f u l in defining areas that
should be more closely studied. Some of the errors that
occurred with the FID study could be minimized if a greater
nurnber of samples were taken, which is reasonable due to the
s p e e d and ease by which a FID study can be conducted. The
shallow gas wells used to collect trace gas sampks proved
to be both easy to use and highly effective f o r this study.
The field work prov ided useful information with respect to
spatial variability in emissions. A t both landfills, the
emissions showed v e r y high spatial variability and higher
omissions alonq the slopes. Higher ernissions on the slopes
could be due to t h e channeling of landfill gas from other
areas to the slopes caused by the higher degree of
compaction and the greater t h i ckness of cover on the top.
The emissions along the slopes could indicate problems with
the i n t e g r i t y of the interim cover at those locations.
Emission levels found at the Regina Fleet Street Landfill
corresponded very well t o the ages of waste in various
locations. In areas over older waste, the south and west
slopes, lower landfill gas emissions were measured. Areas
over medium aged waste, the east slope, showed a higher
ratio of methane t o carbon dioxide, which is to be expected
in l a t e s stages of decomposition. The north slope, that sits
over very young waste, showed high gas emissions with a high
ratio of c a r b o n dioxide t o methane which would also be
expected.
Sorne level of concern was indicated b y t h e VOC
concentrations. The VOC results from the shallow gas wells
were extremely variable between sampling locations a t b o t h
the Regina F l e e t Street Landfill and the Saskatoon L a n d f i l l .
BTEX and v i n y l chloride concentrations were in t h e low t o
medium r a n g e when compared t o l a n d f i l l s in Ontario. The
f r e o n levels were h i g h for one of the gas wells at both
landfills. I t is d i f f i c u l t to make any definitive
c o n c l u s i o n s about trace gas ernissions at either landfill
because of the l i m i t e d number of samples t h a t were t a k e n .
Based on t h e limited VOC data that was collected, high freon
levels w a r r a n t ccntinued scrutiny i n any f u r t h e r studies,
Additionally, vinyl chloxide and benzene emissions, both
known carcinogens, were found in some wells to be i n excess
of OHSA lirnits. A larger number of sarnples need to be taken
at a larger number of locations at each site.
A U.S. EPA Landfill gas mode1 proved to be a u s e f u l tool in
v a l i d a t i n g the field data. The LAEEM mode1 provided
reasonable results considering t h e limited nature of the
available input data. T h e d e f a u l t parameters that most
closely modeled t h e Regina Fleet Street L a n d f i l l w e r e the
CAA defaults for arid conditions, which gave methane
emisçions of 11,170 tonnes/year and carbon dioxide emissions
of 30,065 tonnedyear. These predictions came within 21% of
field estimates for carbon dioxide and within 10% for
methane. This level of error is comparable to other modeled
landfills with comparable input data. Some of the error will
be due to errors in the field data collection and generation
rate estimation procedure, and not solely due to limitations
of the model. The use of a summer emission rate as the basis
for a yearly estimate may explain why the field emissions
are on the high side of the predictions from the LAEEM. The
Environment Canada default values did not model the Regina
Fleet Street Landfill effectively, due to the very low value
of k that was suggested. The use of the LAEEM defaults for
arid conditions appears suitable for simulating this
landf ill.
Based on both the field studies and the modeling results the
Regina Fleet Street Landfill was emitting approximately
10,000 tonnedyear of methane and 32,500 tonnedyear of
carbon dioxide. Based solely on field studies, the Saskatoon
Landfill was emitting approximately 3200 tonnedyear of
methane and 15,000 tonnedyear O£ carbon dioxide. A higher
total emission rate was measured in Regina, 3,711,525
L/hour, as compared to Saskatoon, 1,577,069 L/hour. The
higher ernission rate is pcimarily due to the much g r e a t e r
quantity of waste present in the Regina study area. When an
emission rate per unit of waste is determined, the Regina
Fleet S t r e e t Landfill actually emitted less gas per unit of
waste, 4.65 m'/t~nnes/~ear, than the Saskatoon Landfill, 6.6
m3/tonnes/year. If rubble is not included in the waste from
the Regina Fleet Street Landfill, the emission per unit of
waste at the Regina Fleet Street Landfill changes to 6.65
m3/tonnes/year. The emissions from bath Saskatchewan
landfills fell in the low to medium range of landfill gas
generation estimates from other studies.
The emissions from the Regina Fleet Street Landfill appear
consistent with what would be expected £rom a semi-arid
landfill with interna1 landfill conditions and landfill
generation potential as found at this landfill. The
emissions from the Saskatoon Landfill are also consistent
with expectations assuming conditions are similar to those
at t h e Regina Fleet Street Landfill.
Based on landfill gas emission regulations from both the
U.S. EPA and the government of British Columbia, the Regina
Fleet Street Landfill would be required to control landfill
gas emissions. Because landfill gas generation conditions
are not optimal and therefore landfill gas generation is
hindered, landfill gas utilization may not be feasible and
flaring would be requixed f o r the control of methane and VOC
emissions.
A number of important factors remain to be i n v e s t i g a t e d a t
the Regina Fleet Street Landfill, or any other semi-arid
landfill. Factors remaining to be s t u d i e d are:
1. T e m p o r a l variations in landfill gas e r n i s s i o n s ove r t h e
course of an entire year should be studied through
longer term testing.
2. Additional studies of interna1 landfill conditions and
landfill gas generation are recommended to provide a
b e t t e r i n t e r p r e t a t i o n of emissions a t serni-arid
landfills.
3. Atmospheric conditions, such as barometric pressure and
temperature, should be examined for their impact on
landfill gas g e n e r a t i o n and emissions.
4 . I t i s a d v i s a b l e to conduct more extensive VOC testing at
landfill sites to determine if dangerous levels of VOCs
are being emitted.
5. More intrusive and expensive landfill gas testing may be
warranted in order to validate t h e results from the flux
chamber study and to determine the suitability of
landfill gas collection and utilization,
6 , Site specific va lues of k and L, should be determined so
that they could be used in future landfill gas modeling
a t semi-arid p r a i r i e l a n d f i l l s . T h e s e va lues cou ld be
based on t h e r e s u l t s from t h i s and additional studies.
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Appendix A
Regina F l e e t S t r e e t Landfill FID R e s u l t s .
.I
,
El 4' El 5' El 6' El 7' E l 8' E l 9' B O ' E21 E22 E23
2.8 6 ?O 1.8 0.5 0.4 0.4 0.3 O O
7/8/97 7/8/97 7/8/97 7/8/97 7/8/97 7/8/97 7/8/97 7/8/97
-
7/8/97 7/8/97
PM PM PM PM PM PM PM PM -
PM- PM
0 7 0 8 09"
O1 O* O1 1* 012 013 014 015 016 017 018 019 020 021 022
7.6 40 NA 2
3.1 3.2 62 2.8 3.4 6.4
L
P l O* P l2 Pl3 Pl4 PIS Pl6
7/9/97 7/9/97 7/9/97 7/9/97 719197 7/9/97
6.3 6.8 17 34 28 23
7/9/97 7/9/97 7/9/97 7/9/97 7/9/97 7/9/97 7/9/97 7/9/97 7/9/97 7/9/97
Area not surveyed Area not surveyed Areanotsurveyed
023 024' 025" 026' Pl P2 P3 P4
PM PM PM PM PM PM PM PM PM PM
PM PM PM PM PM PM
9.8 84 14 5.8 5 5
9.4 NA NA NA 52 9.4 13 8.2
I
PM PM PM PM PM PM 1
7/9/97 7/9/97 7\9/97 7/9/97 7/9/97 7/9/97
1
7/9/97 7/9/97 '
7/9/97 7/9/97 7/9/97 7/9/97 7/9/97 7/9/97
PM PM PM PM PM PM PM PM
P23 P24* P25* P26' QI
Q23 Q24' Q25' (226' RI R2 R3 R4 R5 R6 R7 R8 R9
R I O R I i RI2
I
R13
7/9/97 7/9/97 7/9/97 7/9/97 7/9/97
71 NA NA NA 27
19 NA NA NA 44 50 8 2.5 2.8 2 4 2.8 2.4 2.6 2.4 3.8 32 2- 1 1
PM PM PM PM PM
Area not surveyed Area not surveyed Area not surveyed
7/9/97 7/9/97 7/9/97 7/9/97
711 5/97 711 5197 711 5/97 711 5/97 711 5/97 7/15/97 7/15/97 711 5/97 7/15/97 711 5/97 711 5197 711 5/97 7/15/97
PM PM PM PM
AMIPM AMJPM AMIPM AM/PM AMIPM AMIPM AMIPM AM/PM AWPM AMIPM AMIPM AMIPM AMIPM
Area not surveyed Area not sunreyed Area not surveyed
L
R20 O 7/15/97 AMIPM R21' NA 711 5197 AM/PM R22' NA 711 5/97 AM/PM R23' NA 711 5/97 AMtPM R24' NA 7/15/97 AMIPM R25' NA 711 5/97 AMIPM R26* NA 711 5197 AMIPM SI 26 7/15/97 AWPM S2 980 71 1 5197 AM/PM S3 7.6 711 5/97 AMIPM
AM/PM AMIPM AMIPM AM/PM AMIPM
S4 7.6 711 5/97 AMIPM S5 7.5 7/15/97 AWPM S6 7.2 7/35/97 AMIPM S7 7.4 711 5/97 AM/ PM S8 8.3 7/15/97 AWPM
711 5/97 71 1 5/97 711 5197 711 5197 711 5/97
R I 4 R15 RI6 R I 7 RI8
Area not surveved
1.3 0.8 2.1 0.6 0.8
Area not surveved Area not suweyed Area not surveyed Area not surveved Area not suweved
C
S9 S I O S I 1 S I 2 S I 3 S14
. S?6 S i 7 S I 8 SI9 S20'
T l 14 711 5197 AMIPM 4
T2 16 711 5197 AM/PM T3 9 7/15/97 AMPM T4 8.8 7115197 AMIPM
9.1 8.8 15 30 9
8.8
S21* S22* S23'
7/15/97 711 5197 7/15/97 7/15/97 711 5/97 711 5/97
8.3 8.5 8.6 8.4 NA NA NA NA
r
AMIPM AMIPM AMIPM AMJPM W P M
711 5/97 711 5/97 711 5/97 7/15/97 7/15/97
524' S25'
E
AMfPM AMIPM AWPM AWPM AM/PM AM/PM
Area not surveved Area not suweyed Area not surveyed Area not sunreyed
711 5/97 711 5/97 711 5/97
T5 T6 T7 T8
Z
,
AWPM AMfPM AMlPM
8.9 8.4 8.9 1 -6
1
711 5/97 7/15/97
T9 T l O T l 1
*
711 5/97 7/15/97 7/35/97
Area not surveyed Area not surveved
AMIPM AMIPM
3 3-6 34
AMIPM AMPM AMIPM
AMIPM AMIPM
NA NA
711 5/97 711 5/97
711 5/97 711 5/97
AMIPM AMIPM
1 T l 2 1 3.4 1 7/15/97 1 AMlPM 1 1 T l 3 2.8 711 5/97 AMIPM Tl4 10.5 711 5/97 AMIPM T l 5 2.2 711 5/97 AMIPM I
T l 6 2 711 5/97 AMIPM T l 7 1.9 7/15/97 AWPM T l 8 1.4 711 5/97 AMlPM T l 9 1.2 7/15/97 AWPM T20t T21 T22' T23* T24" T25* T26' U1 U2 U3 U4
NA NA NA NA
U5 14 U6 9 U7 2.7 U8 1.9
NA NA NA 66 9.6 9
- 11
U9 U10
711 5/97 7/15/97 7/15/97 711 5/97
71 1 5/97 717 5/97 711 5/97 711 5/97
U12 U13 U14 U15
711 5/97 711 5/97 711 5/97 7/l5/97 711 5/97 711 5/97 711 5/97
AMIPM AM/PM AM/PM AM/PM
2 3
U16 U17 U18' U19' UZO*
AMlPM AMIPM AMIPM AMIPM
U?? 1 NA NA NA NA NA
B
Area not surveyed Area not suweyed Area not sunreyed Area not suweved
AMlPM AMlPM AMIPM AMIPM AMIPM AMIPM AMIPM
711 51 97 7/15/97 .
3.4 2.8 NA NA NA
V3 V4 V5
Area not surveyed Area not surveyed Area not sunreyed
AM/PM AMIPM
711 5197 711 5/97 711 5/97 711 5/97 711 5197
U21' NA
7/15/97 711 5197 711 5/97 7/15/97 7/15/97
U22' U23* U24' U25' U26' V1
8.6 8.9 8.5
AMIPM AM/PM AMIPM M P M AWPM
Active Area Active Area Active Area Active Area Active Area
AMlPM 1
NA NA NA NA NA i 1
7/15/97 711 5/97 711 5/97
AMJPM AMIPM AMIPM AMIPM
V2 8.2 AWPM AWPM AM/PM
Area not surveyed Area not suweyed Area not suweyed
711 5/97 711 5/97 711 5/97 711 5197 711 5/97 7/15/97 7/15/97 AiWPM
AWPM AM/PM AM/PM W P M AWPM AWPM
Area not suweyed Area not sunreyed Area not surveyed Area not suweyed Area not surveyed
I
V16' V17 VI 8' V I 9' V20'
AM/PM AMIPM AMIPM AM/PM AWPM AM/PM AMlPM
V24* V25" V26' W1
711 5/97 711 5/97 7/15/97 7/15/97 711 5/97 711 5/97 711 5/97
V9 V i O* V? l * V12* V13' V I 4* V15'
V Z * NA 711 5/97 AM/PM Area not sunreyed V23* NA 7/15/97 AM/PM Area not surveved
3.1 2.8 NA NA NA
I m
2.6 3.4 4 3.2 2.6 1.9 2
NA NA NA 8.4
L
W W8 W9
W7 O* W1 l *
711 5/97 7/15/97 7/1 5/97 711 5/97 7/15/97
AWPM
711 5/97 711 5/97 711 5/97 711 5/97
7/15/97 W3
I
AM/PM AWPM AM/PM AM/PM AM/PM
I 7.1
W12* W13* W14' W15*
J
Area not surveyed Area not surveved
W? 6* W17' W18'
X2 5.2 7/15/97 AMIPM X3 5 7/15/97 AMPM , X4 5.1 7/95/97 W M
Area not suweyed Area not suweyed Area not surveyed
AMIPM AMPM AM/PM AM/PM
AMlPM AMIPM AM/PM AMIPM AMIPM
II 40 7.8 10 44 7.4 7.2 8.3 7.3
711 5/97 7/15/97 711 5/97 7/15/97
W19' MO* W21"
B
Area not surveyed , Area not sunreyed Area not surveyed
AMIPM AM/PM M P M
7/15/97 7/75/97 711 5/97 711 5/97 711 5/97
AMIPM AM/PM AMIPM AMIPM
7.4 NA NA NA NA NA
W24' W25' W26*
711 5/97 711 5/97 7/15/97
W4 W5 W6
W22' W23*
Area not surveyed Area not surveyed Area not surveyed
711 5/97 7/15/97 711 5/97
6.2 6.4 150
711 5/97 711 5/97 711 5/97
- AMIPM AM/PM AMIPM
AMJPM AM/PM AMIPM
Area not surveyed Area not suweyed Area not surveved
NA NA NA
Area not surveyed Area not surveved
AM/PM AMIPM
NA NA
7/15/97 7/15/97 7/15/97
7/1 5/97 7/15/97
AM/PM AWPM AMIPM
X6 4.7 - X7 4.6 X8 4,2 X9 4.3
>(?O 4.5 *
X I 1 4.2 -
711 5197 7/15/97 711 5/97 711 5197 7/15/97 711 5/97
- Area not surveyed Area not surveyed Area not surveyed Area not surveyed Area not surveyed
AMIPM W P M AMlPM AM/PM AM1PM AM/PM AMlPM AMIPM AWPM AMIPM AWPM AM/PM AMIPM AMIPM AMIPM AMIPM
X12 4.2 7/15/97 X I 3 4 711 5/97 X I 4 X I 5 X I 6 X i 7' XI 8' X19* - =O* X21* X22' X23' X24' X25' X26'
3.9 3.7 3.4 -
NA NA NA
NA CI-
NA 7
h
Y1 Y2
7/15/97 711 5/97 7/15/97 711 5/97 711 5/97 7/15/97 711 5/97 711 5/97
13-
NA NA NA NA NA
AMIPM AMIPM AMIPM
711 5/97 711 5/97 711 5/97 711 5/97 711 5/97
Area not surveyed Area not surveyed Area not surveyed
O -
O
AWPM 711 5/97 711 5/97
Area not surveyed
Y3 O CI
Y26' NA 7/15/97 M P M Area not surveyed _I
Taken with the use of a Flame Ionaation Detector Notes: Sampling accurred at 30 meter intewals unless otherwise stated
7/15/97 7/15/97 7/15/97 711 5/97 711 5/97 711 5/97 7/15/97 7115197 7/15/97 7/15/97 7/15/97 711 5/97 7/15/97 711 5/97 7/15/97 7/ 15/97 7/15/97 711 5/97 711 5/97 711 5197 7/1 5/97 711 5/97
Y4 Y5 Y6 Y7 Y8 Y9
YI0 Y1 1 Y12 Y13 Y14 Y15 Y16 Y17* Y18* Y19' Y20' Y21' Y 22' Y23* Y 24"
AMIPM AM/ PM
O O. 1 0.2 0.8 0.3 0.4 0.2 0.3 O
0.9 O O
0.2 NA NA NA NA NA NA NA NA
I
AM/PM AMIPM AMIPM AMIPM AM/PM AMlPM AM/PM AMIPM AWPM M M AMIPM
r - C r i *
AMIPM AMIPM AM/PM AMIPM AM/PM AM/PM AMIPM AMPM AMIPM AMIPM AWPM
1
-
s
Areanotsurveyed -
Area not surveyed Area not surveyed Area not surveyed Area not surveyeâ Area not surveyed
I
Area not sutveyed Area not sunreyed
= indicates that the grid stake at that point could not be found so the location was estimated
NIA = That a sample could not be taken due to location of sampling point (Le. location was on a steep slope or else in an area that was being actively worked)
Appendix B
Regina F l e e t Street L a n d f i l l VOC Results.
Propane 25422 25433 O
Freon22 4445 4595 9
1 -Butene/2-Methylpmpene
1 ,%Butadiene Butane
t-2-Butene 2,2-Dimethylpmpane
Bromomethane f
1-Butyne
c-2-Butene
Chloroethane
2-Methylbutane
Freon 1 1
1 -Pentene
2-Methyt-1-Butene
Pentane
24703
4579
1 026
O
104
11411
616
Freonl2
Propyne
Chloromethane
lsobutane (2-Methyipropane) Freonll4
lsoprene (2-Methyl-t .3-Bu tadiene) Ethy lbromide
t-2-Pentene
1.1 -Dichloroethene
e2-Pentene
DichIoromethane 2-Methyl-2-Butene
Freonll3
2.2-Dimethylbutane
Cyciopentene t-4.2-DichIomethene
4-Methyi-1 -Pentene
3-Methyl-1 -Pentene
1 ,l-Dichloroethane
6103
O
14827
810
O
O
O
679
129
14831
O
O
O
10995
23924 4536 ---- 922
O
33 10252
599
Vinvlchloride (ChIometthenel
915
O
11 1
10380
574
O
O
O
O
O
201
1272
24
467
3
1
10
68
10
3 3-
948
6076
O
13538
526
O
O O
527 121
1 3470
O
O
O
1 0873
-1 963
807
O
59
l m 6
579
O
O
292
6
259
188
1 342
1 O
457
- 12
47
3 -1
O
9
35
22
6
9
1014
6 I -
-6
59 2
37
286
O
106
38
-5 1 942
6723
O
15256
683
O
O
O
61 3
1 62
15528
O
O
O
-22
-5
-1 0
4
45
300
O
116
37
1 1 121 77
O
O
220
O
1 74
454
6131
O 1 3654
408
O
O
O 404
149 13733
6
O
O
9
11
40
34
8
12
1 0940
O
O
304
O
273
6 I
4
I
22i
01
47
279
O
158
n
1 O
-38
-57
45
240
O
1 23
nl
2
n 5
1349
17
475
393
1310
7
449
13
I
Cyclopentane -
2.3-Dirnethylbutane L
t4Mettryl-2-Pentene
2-Methylpentane c4Met hyl-ZPentene
SMethylpentane 1 -HexeneM-Methyl-1 -?entene
c-l,2-Dichloroethene
Hexane Chloroform I
t-2-Hexene 2-Ethyl-1-Sutene t-3Methyî-2-Pentene
c-2-Hexene ~Wethyl-2-Pentene
2.2-Dimthylpentane - 1,2-Oichloroethane
Methylcyclapentane
2.4-Dimethylpentane -
1,1,1 -~richloroethane- -
2.23-Trimethyfbutane
1 -Methylcyclopentene -
Benxene I - Carbontetrachloride
Cyclo hexane 24ethylherane
2.3-Dimethylpentane
Cyclohexene
3-Methylhwane Oibromornethane
1.2-Dichloropropane Brornodichlommethane
Trich loroethene
1 -Heptene 2,2,&Trimethylpentane
t-3-Heptene c-3-Heptene
Heptane
t-2-Heptene c-2-Heptene
1147
1121
O
5765
175
3921 O
249 5566
O
139 112
O
O
O
O
O
3943
700 O
O
1 38
4637
O
2402
541 5
2456
7 1
7224
O
O
O
1 32
O
1959
O
O
10447
O
O
2.2-Dimethylhexane 625 703 Methylcyclo hexane 9928 8627
2.5Dimethylhexane 1775 1715 1 - _ 2.4Dirnethylhexane 2242 2223 -_ c/t-1.3-Dichlompmpene O O
1.1.2-Trichloraethane O O
Brornotnchlommethane O O
2,3,4-Trimethylpentane 1266 1214
-1 3
13
3 1
4
1142
1 on O
6058 195
3576
O
250 5329
O
1 84
145
O
4
-5
-1 2 9
-1 4
-32
-29
O
9058
1731 21 56
O
O
O
1280
1 O
11
12
-3 6
I
-3 S
-14
3
12
- -
3 9
-2
2
3 2 9 8
5
-11
11
12
1261
1185
O
6546
205 3934
O
270 5909
O
159
1 54
O
O
O
O
O
4490
739 .
36
O
150
4749
O
2904 5173
2574 84
71 93
O
O
O
1 53 O
21 29 O
O
1 0969 O
O
1136
1051 O
W68
21 1 3710
O
279
5596 O
1 82 1 50
O
O
O
O
O
3961
718 - - - - -
33 O
152
4673 O
2813
5082
2339
78
6842 O
O
O
1 70
O
1903
O
O
9705 O
O
O
133 O
205
O
3904
71 1
14
O
148 4582
O
2666
4987
2384
76
6859
O
O
O
1 57 O
1958
O
O
10038
O
O
8668
1664
21 77
O O
O
117 9
1
1
-1
-7
1
-1 1
8
3
-7
5
-1 9
O
4 m
4
4
-1
8
O
Toluene
2Methyl heptane
4Methylheptane 1
1 -MethylcycJohexene
Dibrornochloromethane
SMethylheptane
c-1.3-Dirnethylcyciohexane
t-1,4-Dimethylcyclohexane
EDB (1,2-Dibromoethane)
2,2,5-Trirnethylhexane
1 -Octene
Octane
t-1,2-Dimethylcyclohexane t-2-Ode ne
Tetrachloroethene
cl ,4/t-1,3-Dimethylcyclohexane
c-2-Octene
c-1.2-Dimethylcydohexane Chlorobenzene
Ethylbenxene
mipxylene
Bromoform
l&Dichlorobutane
Styrene
1.1.2,2-Tetrachloroethane
3.6-Dirnethyloctane
n-Propylbenzene
3-Ethyltoluene
4Ethyltoluene
1 -3.5-Trimethylbenzene
ZEthyltoluene
1 -0eœne
tert-Butylbenzene
1.24-Trimethylbenzene
Decane
Benzyl chloride
13-Dichlombentene
1 .CDichlorobenzene
iso-Butylbenzene
sec-Butylbenzene
1 2.3-Trïmethyibenzene
f l ~ e n e 1.2-Dichlorobanzene
lndane
~1.3-Diethylbenzene
2354 9295
11154
403
O
1 0585
4973
2401
O
O
O
7884
4205
1711
162
1466
O
1040
1088
54731
41 259
O
O
O
O
O
3140
7329
O
5450
4325
O
O
2091 4
31 047
O
O
548
SO
1197
7064
1 9539
O
967
1214
2300
8404
3325
420
O
10561
4507
O
2401
4864
1384
41 54
3238
O
O
14083
20765
O
3
478
448
923
4763
1 1 927
O
793
2584
9555
3701
381
O
11170
4865
2 1 O
70 -4
O
9
2747
O
O
O
7512
4050
1 847 1 73
1428
O
1014
1179
4691 3
37466
O
O
O
O
2539
8090
2783
435
O
9894
4555
1 O
2
15
25 , -1 4
11
6
2774
O
O
O
7295
3938
1847
204
1 394
1428
993
1 058 46990
39480
O
O
O
O
863
O
2436
4794
1334
4065
321 3
O
O
14353
21 562
O
O
494
475
937
4758
1 1 202
O
799
24
34
24
25
33
33
13
21
23
33
39
18
832 1 3 1
-31
12
4
-2
3
2
11
12
3
-14
5 4
-8
-7
3
3 -8
14
9
16
20
16
22
22
26
24
9
29
20
26
27
I
17
2910
601 1
1586
521 8 41 38
O
O
19281
28229
O
O
544
667
1170
6393
15301
O
956
O
21 22 O
O
8327
41 10
O
201
1430
O
1 O1 7
1189
53206
40889
O
O
O
O
Naphthalene 332 248 25 392 253 36 Dodecane 2467 1 657 33 231 5 1 784 23 Hexachlarbutadiene O O O O
Appendix C
Environment Canada k & Lo Values fot the LAEEM.
Environment Canada Default Values for k (Environment Canada, 1997a)
Province - - - - - -
British Columbia O. 028
Alberta 0.006
Manitoba 1 0.006
Saskatchewan 0.006
Quebec 1 0.024
O n t a r i o
N e w Brunswick
- --
0.024
P r i n c e Edwatci Island 1 0 -011
Nova Scotia 1 O.Oi1
Newf oundland
Northwest Territories
0.011
O. 003
Yukon 0.003
Environment Canada Defaul t values fox Lo (Environment Canada, 1997a)
Year Lo (m' of CH4/tonne of w a s t e )
Appendix D
Saskatoon Landfil1 Gas EMssions.
Sampling and Emissions Data for the Spadina MSW Landfill
Saskatoon, Saskatchewan
Sample Location Sampling Tem Emiss ions (~hrlm'). CO2 1 CH4
SEPTEMBER 3(
Sampling and Emissions Data for the Spadina MSW Landfill
Saskatoon. Saskatchewan
L
Sampling and Ernissions Data for the Spadina MSW Landfill
Saskatoon. Saskatchewan L r
Sample Location Sarnpling Temperature (OC) Concentration' (ppm) Emiuions (uhrlm2)' # North East Time ground sample Co2 CH4 Co2 CH4
t m
68 380 425 11:fSAM 17.5 20.0 150 32 2.7 0.6
69 405 460 11:ISAM 18.5 17.0 66 26 1.2 0.5
Sampling and Ernissions Data for the Spadina MSW Landfill
Saskatoon. Saskatchewan
4
Ssmple Location Sampling Temperature CC) , Emlssions (uhrirn2~ # North East l ime ground sample - Co2 CH4 coz CH4
--
102 335 254 9:SO AM 15.0 19.0 280 153 5.1 2.8
Sampling and Emissions Data for the Spadina MSW Landfill
Saskatoon, Saskatchewan
-
Sampling and Emissions Data -
for the Spadina MSW Landfill 1 Saskatoon, Saskatchewan 1
L
Sampling and Emissions Data for the Spadina MSW LandfiIl
Saskatoon. Saskatchewan
1 OCTOBER 5
' Note: Concentrations compensated for zero and span values
* Note: Emissions conected to 25oC
Appendix E.
R e g i n a F l e e t Street Landfil1 Detailed Gas Results.