Evaluation of Waste Reduction and Diversion as

Alternatives to Landfill Disposal

Kevin Lai, Linda Li, Sammy Mutti, Rebecca Staring, Max Taylor, Jun Umali, and Sheree Pagsuyoin University of Waterloo, kyhlai, linda.li, sjmutti, rstaring, max.taylor, hjumali, spagsuyoin@uwaterloo.ca

Abstract – Although the Region of Waterloo implements

a waste recycling program as part of its compliance with

the 2004 Ontario Waste Diversion Goal a large fraction

of its municipal solid waste ends up in the landfill.

Landfill waste disposal adversely impacts the

environment through the release of air pollutants and

greenhouse gases to the atmosphere, and through the

generation of leachate that may contaminate water

sources. Landfills also require large land areas, which

limit their long-term sustainability. This paper presents

a quantitative comparison of the environmental,

economic, and social impacts of the current waste

disposal program in the Region of Waterloo and of three

waste management alternatives: (i) expansion of the

organics collection program with biogas recovery, (ii)

expansion of the recycling program, and (iii) incineration with energy recovery. Environmental

impacts were evaluated by performing a life cycle

analysis using the US EPA’s Waste Reduction Model.

Economic impacts were quantified using cost-benefit

analysis; social impacts were evaluated using a

previously developed scoring scheme. Finally, the over-

all impacts were ranked and analyzed using the Saaty’s

Analytical Hierarchy Process (AHP) to determine an

optimal alternative to landfill disposal. Results indicate

that incineration with energy recovery is ranked the

highest overall in all three evaluation criteria categories.

Incineration results in the greatest gas reductions (86%)

and the lowest cost to implement. Incineration also

ranks the highest in the social impacts ranking due to

reductions in foul odors, potential for attracting disease

vectors, and land requirements. Expanding the recycling

collection improves greenhouse gas emissions by 41% of the current method; it also reduces disposal costs.

Overall, all three alternatives are better than the current

waste disposal method, and incineration is deemed the

optimal waste management option for the Region of

Waterloo.

Index Terms - Solid Waste Management, Landfill,

Recycling, Composting, Saaty’s AHP

INTRODUCTION

The Regional Municipality of Waterloo (2011 population of

544,000) [1] is located in southern Ontario, Canada. It

includes the cities of Cambridge, Kitchener and Waterloo,

and the townships of North Dumfries, Wellesley, Wilmot,

and Woolwich. It operates one active landfill located in

Waterloo City and one waste transfer station in Cambridge

City. The Region provides waste collection, processing, and

disposal to all cities and townships within its jurisdiction. In

2011, a total of 192,623 tonnes of residential waste was

collected from the region [1].

As part of its compliance with the 2004 Ontario Waste

Diversion Goal, the Region currently implements a number

of waste diversion programs for municipal solid waste. The

Blue Box program is intended for recyclable materials such

as glass, plastics, paper and metal. Curbside collection

service is provided to the public and drop-off is also

accepted at several waste management facilities. Two

organics composting programs are in place: the Leaf and

Yard Waste program and the Green Bin program. The

former is dedicated to the collection and processing of yard wastes such as discarded house and garden plants, leaves,

branches, and brush. Curbside collection and drop-off

services are also provided for this program. The Green Bin

program is dedicated to the collection and composting of

source-separated organics (SSO), which are materials such

as food waste, paper napkins and wood chips. Curbside

collection service is available for all single/semi-detached

dwellings in the tri-cities and in the settlement area of the

townships. The Construction and Demolition Waste

Recycling program is intended for construction and

demolition (C&D) waste materials such as, drywall, scrap

metal, ceramic, concrete, brick and wood pallets. C&D

waste can be brought directly to the landfill in Waterloo

City or to a number of drop-off locations in the Region. The

breakdown of this waste by program is shown in Figure 1.

FIGURE 1

2011 WASTE PROGRAMS IN THE WATERLOO REGION

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Despite these diversion programs, a large fraction of the

collected waste from the Region ends up in the Waterloo

landfill. Based on the current waste diversion rates, the

Region estimates that the Waterloo landfill will reach full

capacity in 2031 [2]. Extending the life of the landfill

requires enhancing the existing waste diversion programs or

exploring alternative disposal methods such as incineration.

However, each of these alternatives has economic,

environmental, and social impacts. Selecting an optimal solution requires comparing their over-all advantages and

disadvantages.

In this paper, we evaluate the performance of three

waste minimization strategies for residential waste in the

Region of Waterloo: (i) expansion of the organics collection

program, (ii) expansion of the recycling program, and (iii)

incineration with energy recovery. The objective of the

assessment is to identify an optimal strategy for reducing

landfill requirements, and consequently extend the life of

the Waterloo landfill. The assessment was carried out for

residential wastes generated within the period 2014-2031.

BASE CASE AND WASTE MINIMIZATION ALTERNATIVES

The base case scenario refers to the current waste

management program for residential waste, which includes

landfill disposal and waste diversion. The waste diversion

programs included in this study are the organics collection

program (Green Bin) and Blue Box program. The organics

collection program is still under development, and currently

achieves a capture rate of only 18% [3]. Expansion of the

organics collection program (Alternative 1) above its current

capture rate can be achieved in several ways, for example,

by extending the program to large multi-residential

dwellings, increasing the frequency of collection, and

increasing community awareness of the program. In this

study, the capture rate for organics in Alternative 1 was increased from 18% to 59%. Further, it is assumed that the

collected organics will be transported to the Guelph Organic

Waste Processing Facility in Guelph, Ontario to undergo

aerobic composting.

Expansion of the recycling program (Alternative 2)

entails enhanced collection and processing of recyclables

collected through the Blue Box program. It is noted that the

current capture rate for this program is already high (76%)

[3], but it is possible to increase this rate by increasing

collection frequency and public awareness. In this study, the

recyclables capture rate for Alternative 2 was increased to

88%.

The final waste minimization alternative considered in

this study is incineration with energy recovery (Alternative

3). In the performance analysis, it was assumed that waste

diversion rates will remain at current levels but residual

waste will be incinerated instead of landfilled.

METHODOLOGY

I. Data Collection and Compilation

Data on population growth, waste generation rates and

composition, capture rates for waste minimization

programs, and waste collection and disposal costs were

obtained from interim reports from the Region of

Waterloo’s Waste Management division. Secondary data on incineration performance and efficiency were obtained from

literature.

The yearly waste generation rates were calculated from

population data, per capita waste generation, waste

composition, and waste diversion rates. The unit costs and

revenues for each waste stream (organics, recyclables, and

residual waste) were obtained from the Region of Waterloo

2014 Preliminary Budget Book [4], 2013 Sustainability

Evaluation of Residual Waste Management Options Report

[5], and the Region of Waterloo Waste Management Master

Plan [6]. The net cost of waste disposal for each scenario

(base case and alternatives) is the difference between costs

and revenues generated for each of the waste streams. The

cost-benefit analysis for Alternative 3 (incineration) was

performed using data from a feasibility study [7] of an

incinerator project for the Durham and York Regions, two

municipal regions close to the Region of Waterloo. The waste compositions in these regions are comparable to those

of the Region of Waterloo; hence cost data from the

feasibility study were deemed to be representative of an

incinerator facility required for the Region of Waterloo.

II. Economic Impact Evaluation

A cost-benefit analysis was conducted to evaluate the economic performance of the current waste management

program and the three waste minimization alternatives.

Based on the estimated expenditures incurred in 2013, the

unit cost of landfilling is $150/tonne. The unit revenue

generated from tipping fees is $44/tonne. Thus, the net unit

cost of landfilling waste is $106/tonne [4].

Costs associated with the organics program include

green bin and yard waste collection and processing, at a

combined unit cost of $119/tonne [4]. The Region of

Waterloo has a gas utilization program at the landfill site

managed through a three-way partnership between the

Region, Toromont Energy, and Ontario Power Generation.

The Region owns and operates the gas collection system and

supplies gas to Toromont Energy in exchange for a royalty

based on the amount of electricity sold [2]. The revenue

generated from methane gas sale in 2013 was $14/tonne,

bringing the net unit cost of the organics program to $105/tonne [4].

Costs associated with the recycling program include

costs for blue box collection and processing, at a combined

unit cost of $189/tonne [4]. The revenue generated from the

sale of recyclables in 2013 was $84/tonne [4]. Thus, the net

unit cost of the recycling program is $105/tonne.

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For Alternative 1, an additional cost of $2,961,000 will

be incurred for the expansion of the compost pad.

For Alternative 2, expanding the Blue Box recycling

program will require building and equipment upgrades of

the existing Materials Recycling Center. A total cost of

$4,840,000 is expected for the upgrades [4].

For Alternative 3, the capital and operating costs of an

incinerator were estimated based on the recently built

incinerator for the Durham and York Regions. The facility will be capable of processing 140,000 tonnes of post-

diversion residual waste annually while recovering metals

and energy [7]. The capital cost of the incinerator was $276

million for a service life of 35 years; estimated annual

operating costs are approximately $14.7 million [7].

Estimated annual revenue from the sale of generated

electricity is $8.5 million. For this study, a salvage value at

the end of 2031 was estimated for the incinerator using a

declining balance method and depreciation rate of 4% per

year. The Durham/York region waste composition is similar

to that of Waterloo; also, both are located in Southern

Ontario. Residents of Durham/York and Waterloo have

similar lifestyles, and thus produce similar wastes.

II. Environmental Impact Evaluation

Solid waste life cycle analysis (LCA) using the US

Environmental Protection Agency’s Waste Reduction

Model (WARM) [8] was conducted for the base case and

each of the three alternatives. WARM calculates the

greenhouse gases emissions, reported in equivalent carbon

or CO2, for five waste management strategies: source

reduction, recycling, incineration, composting, and

landfilling. It calculates the emissions associated with a

variety of material components in the waste stream (paper, aluminum, plastic, etc.).

WARM accepts as user inputs the amounts of each

waste component in a waste management alternative. In

this study, the amounts of waste streams in each waste

management scenario were calculated based on data from

recent waste audits conducted by the Region of Waterloo [9]

and from population projections.

III.Social Impact Evaluation

Societal impacts of waste management include effects on

the quality of life, community acceptance, and land use. A

previously derived Social Criteria and Scoring Scheme for

waste management options [5] was used to evaluate the

social impacts of the base case and the waste minimization

alternatives. Six criteria were included in the social impact

evaluation: odor, noise, traffic, other nuisances, public

acceptance, and additional land requirements. In each waste

management scenario (base case or alternative), scores were

assigned to each criterion; higher cumulative scores indicate

lower societal impacts.

IV. Over-all Performance

The over-all performance of the base case and waste

minimization alternatives were evaluated using the Saaty’s Analytical Hierarchy Process (AHP) method, and with

economic, environmental, and social impacts as criteria.

The AHP evaluation consists of two stages: first, the weight

of each criterion, reported as a percentage, is determined;

then for each criterion, scores are calculated for each of the

alternatives. To initiate the AHP evaluation matrix, the

relative importance of each criterion were compared

pairwise and assigned rankings based on a 1-9 scale, with 1

as least important. Similarly for each criterion, the

alternatives were compared pairwise and assigned rankings

based on a 1-9 scale.

RESULTS AND DISCUSSION

I. Waste Generation

The amounts of diverted, incinerated, and landfilled waste

streams over the period 2014-2031 for the base case and

waste minimization alternatives are shown in Table 1. The

total amount of waste generated over this 17-year period is

3.7 million tonnes. Note that the residual ash from the

incinerator will also require landfill space.

TABLE 1

WASTE STREAMS FOR BASE AND ALTERNATIVE SCENARIOS

Scenario Recycled

(tonnes)

Composted

(tonnes)

Incinerated

(tonnes)

Landfilled

(tonnes)

Base Case 767,670 969,690 0 1,939,390

Alternative 1 767,670 1,512,720 0 1,396,360

Alternative 2 864,640 969,690 0 1,842,420

Alternative 3 767,670 969,690 1,939,390 193,940

II. Economic Impact Results

Results of the cost-benefit analysis are summarized in Table

2. The total cost of the base case and each alternative was

calculated from Year 2014 to 2031. At the end of 2031, a

savage value was determined for each purchased equipment

or facility in the alternative.

TABLE 2

COST-BENEFIT COMPARISON OF THE BASE AND ALTERNATIVE SCENARIOS

Scenario Net Cost

($/year)

Base Case 20,858,900

Alternative 1 20,812,000

Alternative 2 20,851,800

Alternative 3 15,855,500

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The cost-benefit analysis shows that Alternative 3,

waste incineration, has the lowest net cost. Despite a high

initial installation cost, the incinerator will have the highest

savage value at the end of 2031. Alternative 2, expansion of

the recycling program, has the second lowest cost. The

lower net cost for Alternative 2 is due to the minimal

increase in recyclables capture rate that can be achieved

considering the already high current capture rate of 76%.

The base case, which is the current disposal method, was found to be the most expensive method.

II. Environmental Impact Results

The summarized results of the WARM calculations are

depicted in Figure 2.

FIGURE 2

REDUCTION OF GHG EMISSIONS FOR BASE CASE AND ALTERNATIVES

Incineration with energy capture (Alternative 3) has the

highest GHG reduction of all three alternatives; the base

scenario has the lowest GHG reduction of all scenarios

studied. The GHG reduction for incineration is 86% better

than the GHG reduction for the base case. The expansion of

the recycling program (Alternative 2) has the second highest

GHG reduction; it also has 41% better GHG reduction

compared to the base case.

III. Social Impact Results

Results of the Social Criteria and Scoring Scheme are

shown in Table 3. The maximum possible score for each scenario, based on 6 social impact criteria, is 600.

TABLE 3

RESULTS OF SOCIAL IMPACT ANALYSIS

Scenario Rating

Base 208

Alternative 1 200

Alternative 2 391

Alternative 3 415

Alternative 3 (incineration) has the highest cumulative

score in the social impacts assessment. Although

incineration has a lower score in public acceptability, it has

higher score in other social criteria (odor levels, nuisance

such as disease vectors, and land requirements). Alternative

1 (expanding organics program) has the lowest cumulative

score of all three alternatives studied, and has comparable

score to the base case scenario. This low score is mainly

attributed to the increased level of odors, noise and traffic

created from the additional trucks needed for collection, and

other nuisances such as vectors and vermin.

IV. Saaty’s AHP Prioritization

Results of the Saaty’s AHP analysis are shown in Table 4.

The calculated weights for the economic, environmental,

and social criteria are 28%, 46%, and 26%, respectively.

These values are not surprising; generally, waste

management programs are implemented for environmental

(and health) reasons rather than for economic profitability.

Similarly, social impacts (with emphasis on the social

impact indicators used in this study) are also considered secondary to environmental impacts.

All waste minimization strategies have higher

cumulative scores in the AHP analysis compared to the base

scenario, indicating that all options are better than the base

case. Alternative 3 (incineration) has the highest cumulative

score and is deemed the optimal waste minimization

alternative to landfill disposal. It scored the highest marks in

each of the three evaluation criteria categories (economic,

environmental, and social). Alternative 2 (enhanced

recycling program) has the second highest cumulative score

followed by alternative 1 (enhanced organics collection).

TABLE 4

RESULTS OF SAATY’S AHP PRIORITIZATION ANALYSIS

Scenario Weighting Base Case Alternative 1 Alternative 2 Alternative 3

Economical 28% 23 23 23 31

Environmental 46% 18 23 26 34

Social 26% 17 16 32 34

Total 100% 19.14 21.18 26.72 33.16

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CONCLUSIONS AND FUTURE WORK

This study shows that implementing alternative waste

minimization strategies can improve the current waste

management program in the Region of Waterloo, and extend

the life of the Waterloo landfill. Findings of this study can

be used by decision makers in identifying alternatives, or

combination of alternatives that can enhance the existing

waste minimization programs in the Region.

Some factors that were not included in the performance

analyses can be included in future work to enhance the

results of the evaluation. For example, potential additional

cost of collection bins for the organics program expansion

was not included in the cost-benefit analysis. It was assumed that this cost was negligible compared to the

capital and operating costs of the waste treatment facility.

Other environmental indicators such acidification, ozone

depletion, and smog formation can be included in the LCA

analysis. These parameters were not evaluated in this study

due to LCA software limitations. Changes in the results of

these analyses can affect the over-all performance analysis,

and shift the preference from incineration to another

alternative.

ACKNOWLEDGMENT

We would like to acknowledge Shahin Virani, the Manager

of Finance & Administration of the waste management

department at the Region of Waterloo for providing us with

the 2014 Preliminary Budget Book.

REFERENCES

[1] Golder Associates Ltd., "Region of Waterloo Waste Management

Master Plan Interim Report No. 1: Waste Generation Projections &

Landfill Capacity Assessment," 2013.

[2] Golder Associates Ltd., "Region of Waterloo Waste Management

Master Plan," 2013.

[3] Golder Associates Ltd., "Region of Waterloo Waste Management

Master Plan Interim Report No. 2: Current Waste Management

Profile," 2013.

[4] Region of Waterloo, "2014 Preliminary Budget Book," 2013.

[5] Golder Associates Ltd., "Region of Waterloo Waste Management

Maste Plan Interim Report No. 5: Sustainability Evaluation of

Residual Waste Management Options," 2013.

[6] Region of Waterloo, "Waste Management Master Plan," 2011.

[7] Durham York Energy Centre, "Facts and Info." 2013. [Online].

Available: http://www.durhamyorkwaste.ca/project/faq.htm.

[Accessed 16 3 2014].

[8] U.S. Environmental Protection Agency, "Waste Reduction Model

(WARM)," 2013. [Online]. Available:

http://epa.gov/epawaste/conserve/tools/warm/index.html. [Accessed

18 3 2014].

[9] Golder Associates Ltd., "Region of Waterloo Waste Management

Maste Plan Interim Report No. 6: Life Cycle Assessment &

Evaluation of Short-listed Alternatives," 2013.

AUTHOR INFORMATION

Kevin Lai, Undergraduate Student, Department of Civil and

Environmental Engineering, University of Waterloo.

Linda Li, Undergraduate Student, Department of Civil and

Environmental Engineering, University of Waterloo.

Sammy Mutti, Undergraduate Student, Department of Civil

and Environmental Engineering, University of Waterloo.

Rebecca Staring, Undergraduate Student, Department of

Civil and Environmental Engineering, University of

Waterloo.

Max Taylor, Undergraduate Student, Department of Civil

and Environmental Engineering, University of Waterloo.

Jun Umali, Course Assistant, Department of Civil and

Environmental Engineering, University of Waterloo.

Sheree Pagsuyoin, Professor, Department of Civil and

Environmental Engineering, University of Waterloo.

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