CONCLUSION

1
Curbing Climate change through Organics
Diversion Results of a National Survey Rathan
Bonam, Dr.Shirley Thompson Dr. Nicola
Koper Natural Resources Institute, University of
Manitoba
METHOD 1. Surveyed 300 landfills regarding waste
and landfill gas. 2. Analyzed data descriptively
and by province to determine how waste management
differs by province. 3. Determined relationships
after meeting linear regression assumptions
(required logging landfill emissions, density of
waste, waste diverted, current waste, waste
capacity, organic content, recycling and
composting) at the 0.05 probability level
defining significance with S-Plus statistical
software version 7, between - waste
management practices and measured methane
emissions - waste management practices and
diversion and - determination of what is
important to model emissions. The statistical
model Y ß0 Xi1 ß1 Xi2 ß2 Xi3 ß3 Xi4 ß4
Xi4 ß4 e assumed a linear relationship
between the following variables (where e is an
observational error, ß0 (intercept) and ßn
(slope)) Independent Variables Xi1 Waste
diverted in 2005 from the landfill (log) Tonnes
Xi2 Total current waste (log) Tonnes Xi3
Organic waste disposed in 2005 (log) Tonnes
Xi4 Depth of the waste placed in the
landfill Meters Xi5 Disposal fee/tipping
fee of the landfill Dollars Dependent
variable Y Measured landfill emissions in 2005
(log) Kilo Tonnes All these five independent
landfill variables were not correlated either
positively or negatively with each other
(considering rgt0.6). All variables followed a
normal distribution. 4. Determined whether actual
methane emissions and modelled emissions could
benefit from other factor 5. Determined GHG
savings from recycling and composting based on
the overall GHG releases through the life cycle
of a number of materials which form a
considerable part of the MSW waste stream.
Figure 1 Landfill Gas capture sites across Canada
ABSTRACT To reduce greenhouse gas (GHG) and
determine best practices for sustainable waste
management the relationships between landfill
gas, diversion rates, management methods and
landfill characteristics were explored for 130
landfills across Canada.  Significant GHG occur
from Canadian landfills but methane recovery is
only occurring at landfills using best management
practices (high density, higher disposal fees,
greater depth and higher diversion) but should be
carried out at all landfills above a minimum size
to reduce GHG. A linear regression analysis
showed that landfill emissions are positively
linearly correlated with landfill depth, density
and organic waste and negatively correlated to
waste diversion and disposal fee. Waste
diversion's impact on GHG is significant enough
for the nation to concentrate more on waste
reduction, including composting and recycling
programs to provide the long-term solution to
reduce GHG production and waste generation.
BC
AB
7
INTRODUCTION Canadas high greenhouse gas
(GHG) emissions per capita from solid waste
disposal on land require that new strategies to
reduce methane emissions including organic
diversion and methane recovery. Canada has the
second highest methane emissions per capita from
solid waste disposal on land among the numerous
countries in the United Nations Framework
Convention on Climate Change Parties (UNFCC,
2003), due to burgeoning waste per capita, lack
of widespread organic diversion and limited
methane recovery. Landfill gas is basically made
up of half methane and half carbon dioxide (CO2),
two potent greenhouse gases, as well as small
amounts of hydrogen, oxygen, nitrogen, hydrogen
sulphide and trace amounts of non-organic
compounds and volatile organic compounds (Gardner
et al., 1993 Schumacher, 1983). In Canada,
methane emissions account for approximately 12.6
of Canadas CO2 equivalent (eCO2) GHG emissions
with almost one-quarter (24) arising from
landfills (Canadian Electricity Association,
2002). Methane is typically generated during a 30
to 50 year period as waste undergoes anaerobic
decomposition. Methane is the central concern for
greenhouse gas emissions from landfills as it has
23 times the global warming potential of CO2
(source ). However, the CO2 produced from
burning or aerobic decomposition of biomass,
unlike methane, is deemed a sustainable cycle, as
carbon in CO2 is sequestered when the biomass
regenerates (Environment Canada, 2003).
Landfill gas recovery, organic waste diversion as
well as other waste management aspects of 130
landfills were collected by a national survey to
determine best management practices to reduce
GHG. Municipal solid waste composition and
quantity varies substantially by location and
waste management systems (Bonomo and Higginson,
1988 Senior, 1990). In Canada, municipalities
manage waste under provincial certificate of
approvals. Municipalities and/or provinces are
able to ban organics or require landfill gas
capture but few do. Only Ontario and Alberta
are requiring landfill gas recovery of larger
size landfills and only Nova Scotia and Prince
Edward Island ban organics from landfills.
The systematic recovery and utilization of
landfill gas generated during anaerobic
decomposition of municipal solid wastes both
reduces GHG emissions and creates an alternative
renewable source of energy to replace fossil fuel
use (Pembina Institute, 2003 Smith et al.,
2001). If the methane was recovered from one
tonne of waste it could produce approximately
1000 kilowatt hours (kWh), as one cubic meter of
methane gas has an energy value of four to five
kWh (Pembina Institute, 2003). Methane recovery
of landfill gas represents one of the most cost
effective means to reduce GHG emissions due to
both fuel sales and credits from GHG reduction
(Conestoga Rovers and Associates, 1999). In
addition, the capture and use of landfill gas
provides the ancillary benefits of limiting
odours, controlling damage to vegetation,
minimizing owner liability, reducing risk from
explosions, fires and asphyxiation, and smog
while providing a potential source of revenue and
profit (Smith et al., 2001). Despite its
many benefits, methane recovery is essentially an
end of pipe solution, which does not actively
tackle the root cause of waste generation, unlike
composting. Composting organic matter considers
broader ecological issues such as resource-use
efficiency, avoided ecological impacts, and
improvements in soil stability, fertility and
moisture-retaining properties (Smith et al.,
2001). Under aerobic conditions, methane is not
produced in composting operations, however,
usually some anaerobic decomposition occurs due
to the incomplete aeration of compost. Source
separated organic composting programs are
uncommon outside of tbree provinces (Nova Scotia,
Ontario and Prince Edward Island) and a few urban
centres and only started to become popular across
Canada in early 2000 (van der Werf and Cant,
2006). A national survey of composting in Canada
found that 135 municipalities have curbside
composting programs, reaching 17 million people
(van der Werf and Cant, 2006). All of these 135
municipalities have yard waste composting and 40
of these have source separated organic programs.
Nova Scotias landfill ban on organics
contributed to Nova Scotia reducing its waste
disposal rate to half of other provinces, with an
overall 56 diversion rate from landfills (Betts,
2007). Halifaxs rates of organic diversion at
68 almost reaches that of EU, where organic
diversion rates are above 80 for Austria,
Belgium (Flanders), Germany, Switzerland,
Luxembourg, Italy, Spain (Catalonia), Sweden and
the Netherlands (ECN, 2007). These countries all
have country-wide policies that require source
separation of organics or ban organics from
landfills. van der Werf and Cant (2006)
considered that it was feasible to divert 50 of
Canadas organic waste or 2.9 million tonnes/year
through composting. The Scholl Canyon
model is applied to estimate the energy potential
of Brady Road Landfill. This simple model is
widely used in the landfill gas industry in
Canada and the United States, particularly for
landfills with greater than one million tonnes of
waste in places (Environment Canada, 2003 US
EPA, 1996). However, it has never been used as a
management tool to compare different waste
management options. This model is consistent with
Environment Canada and IPCC climate change
protocols for calculating GHG emissions. The
Scholl Canyon model assumes that after a lag time
of negligible duration, during which anaerobic
conditions are established and the microbial
biomass are built up and stabilized, the gas
production rate is at its peak (Schumacher,
1983). This model is an exponential decay model
dependent on factors that affect biodegradation
rates (e.g., age of waste, moisture content,
etc.) used to estimate methane generation from
landfills but has not been applied to compare
waste management options.
2
QC
7
0
10
ON
10
2
12
NS
National Summary 52 Operational Projects (67 MW
and 4,234,814 million BTU) 30
Active sites 22 Closed sites
1
1
RESULTS National Survey Results The response
rate was 43 (i.e. 130 landfills with 97 being
active) and 52/52 or 100 landfills of the gas
capturing systems in place. The findings in Table
1shows that many provinces have limited waste
capacity. Many landfills are trying to extend the
life of their landfill by increasing density,
depth, disposal fee and increase diversion. The
total amount of landfill gas recovered in both
closed and open landfills is 52 landfills (314 kt
of methane) and of that 215,800 or 60 of the
landfill gas recovered is from landfills that
continue to receive waste. Those recovering
methane are larger landfills with better
management, that is greater density, increased
depth, higher diversion rates and more expensive
disposal fees. The contrast between all of
Albertas landfills for diversion and depth
compared to the one recovering methane reflects
that this alternative is municipally driven and
not a result of provincial policies and programs.
Approximately one-third (32) of the landfills
recovering methane plan to close within five
years. Seventeen active landfills had waste
composition data from audits which we compiled to
find that the organic composition in landfills
ranged from 41 to 100. The average organic
composition was 63 including wood, food,
garden and non-food waste and paper and
textiles.
Table 2 Characteristics of 28 of 30 active LFG
projects by Province Note 22 landfill gas
recovery collected from closed landfill
Table 1 National Survey Findings for 130
landfills organized by Province
Graph 1 Waste Composition from audits of 17
landfills across Canada
Province Waste Disposed in 2005 Waste diverted in 2005 Waste Capacity (tonnes) Average Density (Kg/m3) Average Depth (m) Disposal Fees () Total LFG captured (tonnes/yr)
NS (1) 157,771 29 3,600,000 780 20 115 5,390
QC (10) 4,751,289 6 192,458,548 934 24 44 141,180
ON (10) 1,715,671 11 67,968,776 893 20 64 39,390
AB (1) 250,000 44 13,500,000 850 43 42 4,170
BC (6) 1,387,247 28 65,300,000 850 15 65 25,680
Total 8,261,978 24 342,827,324 860 25 66 215,800
Province Average Landfill Depth (m) Total Waste disposed in 2005 (tonnes) Current Waste (tonnes) Waste Capacity (tonnes) Average Density (kg/m3) Average Disposal Fees () Waste diverted
AB 12 1,443,681 22,674,427 102,054,139 500 25 13
BC 15 1,287,247 25,898,000 53,800,000 900 65 29
NB 15 281,447 3,287,849 22,775,000 750 61 -
NS 20 275,324 1,520,699 10,045,760 730 64 22
ON 20 3,911,351 64,234,313 155,156,327 725 63 16
PEI 22 33,376 148,400 371,000 700 100 54
QC 20 4,821,571 105,315,590 196,313,230 900 50 6
Average/Total 20 750 65
Graph 2 Correlation of Actual Emissions to
Scholl Canyon methane model and depth
Table 3 Statistical Model of important factors
related to methane emissions
Graph 3 Greenhouse emissions saved by composting
and recycling including saving embodied energy in
products
Log (2005 Measured Methane Emissions) - 5.6703
0.6776log (Current waste) 0.0111Depth of
waste 0.5003log (Organic waste disposed)
0.2871log (Waste Diverted in 2005)
0.0035Disposal fees.
Value Std. Error T value Pr(gtt)
(Intercept) -5.6703 0.8138 -6.9678 0.0000
Waste in Place (log) 0.6776 0.1565 4.3287 0.0003
Depth of waste 0.0111 0.0049 2.2553 0.0344
Organic waste (log) 0.5003 0.1311 3.8168 0.0009
Waste Diversion (log) -0.2871 0.1111 -2.5843 0.0169
Disposal waste 0.0035 0.0035 1.0115 0.3228
Residual standard error 0.2928 on 23 degrees of
freedom Multiple R-Squared 0.824, F-statistic
20.6 on 5 and 23 degrees of freedom The p-value
is 0.0000001242
Statistically significant at 0.05
CONCLUSION Greenhouse gas emissions from
landfills dictates that Canada needs a strong
policy to reduce organics and require methane
recovery for medium and large landfills. The
variation across the country and within provinces
in waste management practices and methane
recovery show the lack of an overall Canadian or
provincial policy. Provinces across Canada should
adopt the best practices that only a few
provinces have adopted. Regarding landfill gas
recovery, Ontario recently required larger
landfills to recover methane. All other provinces
should make it a requirement of all landfills
above a minimum size. The method to estimate
methane emissions should consider depth of waste
to improve accuracy. Regarding
composting, both Prince Edward Island (PEI) and
Nova Scotia banned organics from landfill. PEIs
diversion rate is 54 and Nova Scotia is 30.
Other provinces have no source separation of
organics programs and divert waste through
user-pay systems. Banning organics reduce GHG a
linear regression analysis showed that landfill
emissions are positively linearly correlated with
landfill depth, capacity and organic waste and
negatively correlated to waste diversion and
disposal fee. In addition, organic diversion
would help resolve the crisis of closing
landfills by extending the life of landfills.
Further, best practices to extend landfill life
include deep landfills, higher disposal fees and
more diversion practices. Deeper landfills are
more economical for infrastructure of liner,
reduced land-base and higher methane recovery in
deeper wells. Waste diversion's impact on GHG is
significant enough for the nation to concentrate
more on waste reduction, including composting and
recycling programs to provide the long-term
solution to reduce GHG production and waste
generation.

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ACKNOWLEDGEMENTS The authors are grateful to
Environment Canada for supporting this survey.