Beneath the Streets: New
Tools for Managing Degrading
Sewer Infrastructure

Final Report
Final Report

Table of Contents
List of Acronyms and Terms .......................................................................................................... 3
Abstract ........................................................................................................................................... 4
Introduction ..................................................................................................................................... 5
Context ............................................................................................................................................ 6
Literature Review............................................................................................................................ 9
Infrastructure and Sustainability ................................................................................................... 13
Applied Project Methodology ....................................................................................................... 18
Findings......................................................................................................................................... 22
Overcoming Project Challenges ................................................................................................... 27
Conclusions ................................................................................................................................... 28
Future Directions .......................................................................................................................... 29
References ................................................................................................................................... 302
Acknowledgements ..................................................................................................................... 324

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List of Acronyms and Terms
BMP

Best management practices

EPA

Environmental Protection Agency

FOG

Fats, oils, and grease

FSE

Food service establishment

GTAP

Grease Trap Assistance Program

IAP

Infrastructure Assistance Program

SSO

Sanitary sewer overflow

TGC

Tempe Grease Cooperative

WCED

World Commission on Environment and Development

WWTP

Wastewater treatment plant

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Abstract
Infrastructure degradation is a chronic problem for fats, oils, and grease (FOG) pretreatment
programs at wastewater utilities, which can lead to harmful bypass and high loss of a renewable
energy feedstock. Not only does this exacerbate the potential for environmental harm, but not
taking advantage of this resource leaves most FOG anaerobic digestion programs non-resilient
and non-scalable. It is vital that there are strategies utilizing a sustainability perspective and
integration of hard and soft infrastructure management principles to address this infrastructure
degradation issue before there can be fully implemented zero-waste, FOG resource recovery
initiatives. This applied project sought to answer the question, “How can municipalities
sustainability manage the issue of degrading FOG pretreatment infrastructure?” with an
emphasis on providing an applied example where a sustainability approach can mitigate
complex, infrastructure problems. In partnership with the City of Tempe’s Environmental
Services Section, this project addressed the issue of degrading infrastructure by crafting and
implementing a comprehensive Infrastructure Assistance Program (IAP). Designed to assist food
service establishments (FSEs) and wastewater utilities, the IAP provides pathways for preventing
FOG infrastructure degradation through initiatives that bolster hard and soft infrastructure to
support a more efficient means of achieving compliance and local goals for resource recovery
and renewable energy.

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Introduction
In the City of Tempe, Arizona there are 1000 food service establishments (FSE’s) ranging
from local and small restaurants to national hotel and fast food chains. Residents, students,
faculty, business-owners, and tourists visit these community landmarks throughout Tempe every
day, unknowingly contributing to a major environmental and community pollution issue. Every
FSE discharges a pollutant known as fats, oils, and grease (FOG). FOG is found in almost all the
foods we eat; from the obvious greasy burger and fries to our morning coffee and everything in
between. As this pollutant builds-up in private sewer lines, it can create blockages, private
kitchen backups, and odors in the establishment. In the worst-case scenario, when this pollutant
is discharged unchecked into public sewer systems, it can result in blockages which can cause
sanitary sewer overflows (SSOs). These expensive and harmful backups are typically prevented
by capturing FOG at the restaurant in pretreatment devices known as grease traps or grease
interceptors. Capturing this pollutant not only minimizes the risk for backups but FOG is also an
energy-rich resource which can recovered for local renewable energy solutions. Unlike other
organic bio-stocks, FOG contains a high lipid content; due to this feature, not only can FOG be
converted independently as bio-fuel but is also the most efficient feedstock blend component for
all other organic fuels, leading to higher conversion efficiency coefficients and a more stable biofuel generation process (Skaggs, 2018). Traditional models of wastewater pretreatment manage
FOG only as a waste product, and rarely consider its potential as a resource. This perspective
perpetuates a linear model of enforcement and disposal, with an emphasis on a cradle-to-grave
life cycle, which is a wasted opportunity for a sustainability outcome. By looking at FOG from
the perspective of resource recovery, emphasizing a circular, cradle-to-cradle life cycle, the
model of FOG management could take a systems-thinking approach to align infrastructure with
resource recovery.
Every municipality adopts plumbing codes that are maintained by the utility that dictate the
service frequency and cleaning procedure requirements to be followed by restaurants and the
companies that service them. In the traditional FOG pretreatment model, the burden of
maintaining compliance rests on the ability of restaurant owners to monitor and assess the quality
of third-party services, most important of which are those services related to pumping out the
contents of the grease trap or interceptor. If these services are not performed correctly, the
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responsibility of addressing environmental enforcement from the city is tied to the restaurant
owner, usually at their expense. In addition, municipalities and their wastewater pretreatment
programs dedicate enormous amounts of time and resources to inspecting the FOG infrastructure
at each individual FSE to monitor the device condition and potential for FOG bypass,
unfortunately with limited success. Often, there are more FSE’s than city resources and
inspection staff, which can lead to low compliance rates and FOG bypass. The EPA estimates
that only 30% of FSEs across the country are in compliance with FOG regulations
(Environmental Protection Agency, 2017), which is consistent with observed compliance rates in
Tempe. Higher rates of non-compliant FSEs means more FOG is bypassed to sewer, which can
increase the likelihood of downstream backups. The other concern is the high loss of FOG
resource from device failure and infrastructure degradation due to improper maintenance
procedures at the restaurant premise.
The gaps in the current state of FOG management called for an adaptation of the principles
around sewer management, environmental regulation, and resource recovery. In this vein of
thinking, the City of Tempe, designed and implemented a new model of FOG management,
called the Grease Cooperative to address some of these wide-spread problems. While the Tempe
Grease Cooperative (TGC) has had success in addressing some of the historical concerns with
traditional FOG management, there are limitations to the program that hinder the long-term goal
of recovering FOG as a resource. Furthermore, the TGC has unintentionally led to unforeseen
consequences and new challenges, specifically related to infrastructure which now need to be
mitigated. This project will seek to address these limitations and unforeseen consequences by
applying a sustainability approach to the question of infrastructure.
Context
Though the Tempe Grease Cooperative (TGC), the burden of monitoring and assessing
the quality of utility-mandated, third-party pumping services has become the responsibility of the
utility. Restaurants and other FSEs can voluntarily enroll and purchase “grease compliance”
(Figure 1). The goal of the TGC is to act as a business advocate rather than as traditional
regulator. The TGC assures proper maintenance of the device, establishes hauler accountability,
allows restaurants to focus on their business, and ensures the city to own the FOG waste for
maximum collection and potential for reuse as a renewable energy feedstock. The Tempe Grease
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Cooperative has reframed the relationship between public and private institutions and solved
many of the problems associated with traditional FOG pretreatment models.
After four years of
implementation, one-fifth of the
city’s FSEs, approximately 200
establishments, have voluntarily
enrolled into the TGC. In the last
year alone, the city collected and
assumed ownership of

Figure 1: Traditional model of FOG compliance (left) and the TGC
model of FOG compliance (right).

approximately 600,000 gallons of waste, which, if it were to be used for energy generation has
the potential to create 4.8 million cubic feet of renewable natural gas, based on EPA estimates
(Environmental Protection Agency, 2017). The bulk purchasing discounts achieved through the
TGC have saved participating restaurants over $92,000 in service costs compared to standard
market pricing. Used fryer oil collected for biodiesel production in 2017 provided an additional
$16,000 in credit back to participating restaurants. The city estimates a savings of over $250,000
per year in treatment costs to the regional wastewater treatment plant, with most of that cost
savings related to energy consumption, resulting in a reduction in Tempe’s carbon footprint.
Like many other sustainability solutions, the Tempe Grease Cooperative recently underwent
a period of reflection to identify opportunities of growth within the program itself, which
eventually evolved into the TGC’s 5-Year Strategic Plan (City of Tempe Environmental
Services, 2017). The Strategic Plan identified several opportunities for the program to continue
improving. First, a software solution was needed in order to expand the program and its
membership further as existing administrative staff and resources were already operating at full
capacity. Second, pretreatment devices naturally degrade even with the proper maintenance
frequencies and proper cleaning procedures. It has been observed in some new, metal devices
that they experience complete device-breakdown within two to three years, instead of the
expected five or six years, which then requires a costly, full-trap replacement. Third, TGC
members face increased scrutiny when it comes to repairs and compliance. When a device begins
to degrade, it often does not cause a sudden problem; rather, it is a chronic issue that builds-up
over time. Through the TGC, the pumpers perform a device health check at each service, which
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is dictated by the plumbing ordinance. A monthly device check is performed at every indoor,
grease trap pumping service and members with larger devices, such as outdoor grease
interceptors, have their device checks at each quarterly service. Pumpers become an asset rather
than a liability to city staff as they have similar technical expertise as the inspection staff to be
another pair of eyes diagnosing device degradation. This benefits the city and the restaurant
because inspection staff can be notified of these issues before they become a costly expense.
However, since utility resource constraints often result in inspections for non-TGC members as
infrequent as once every seven years, device degradation and the accumulation of FOG bypass
have the potential to build up to a much more serious and expensive problem. Timely
identification of degrading infrastructure and possible FOG bypass issues has long term benefits
for the city, the sewer infrastructure, and the restaurant. However, the relatively smaller upfront
cost is difficult for local restaurants to absorb. This system has inadvertently created a financial
and regulatory inequity between TGC and non-TGC restaurants. Finally, estimates from the EPA
illustrate that up to 17,000 pounds of FOG are bypassed from each failing device in a restaurant
annually to the public sewer system (Environmental Protection Agency, 2007), which is a
hinderance to successfully implementing the FOG-to-Fuel model.
Infrastructure degradation has been identified as a major problem for all FOG pretreatment
programs and is not exclusive to the TGC or the City of Tempe. Previously, the TGC utilized the
traditional enforcement model to address infrastructure issues, but this strategy lacked a critical
holistic, systems thinking perspective. This approach contradicted the sustainability-focus of the
business advocacy and regulatory
partnership that is foundational to
the TGC’s success. In an effort to
improve upon this issue and others,
Tempe’s Environmental Services
drafted measurable long-term
strategic goals to reach the future
vision of this program. The goals
are to (1) establish a project-specific
plan for 100% recovery of diverted
FOG by 2022, and to (2) achieve
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Figure 2: The intersection of the infrastructure degradation influencing
factors and the IAP Model’s connection.

85% compliance-assurance for restaurants by 2023 (City of Tempe Environmental Services,
2017). Through the desired future-state vision, it quickly became clear that a sustainable
approach to infrastructure management, both within and outside the TGC, was necessary to
achieve these long-term strategic goals. The method to achieve these strategic goals was to
identify an intervention point at the intersection of infrastructure compliance, restaurant equity
and advocacy, and resource recovery (Figure 2).
This project tackled the degrading infrastructure issue by applying sustainability
competencies and strategies for an innovative, alternative methodology and outcome to manage
infrastructure rather than continuing to use the inefficient and unsuccessful, business-as-usual
enforcement strategies. The Infrastructure Assistance Program (IAP) assists FSEs and
wastewater utilities alike by providing pathways for preventing and managing FOG
infrastructure degradation to support higher levels of resource recovery. This project has
identified and addressed the gaps in the existing FOG program and has answered the following
question:
How can municipalities sustainably manage the issue of degrading FOG
pretreatment infrastructure?
Literature Review
SANITARY SEWER OVERFLOWS AND PRETREATMENT TECHNOLOGY
The EPA estimates that 23,000 – 75,000 sanitary sewer overflows (SSOs) occur each year
throughout the United States which results in billions of gallons of untreated sewage entering the
environment and surrounding waters (Environmental Protection Agency, 2017; Environmental
Protection Agency Office of Wastewater Management, 1996). An SSO is an event where
untreated sewage waste is discharged into the environment prior to reaching treatment facilities;
and this can have profound consequences regarding environmental and human health as well as a
high financial cost to the community. Untreated, raw sewage can carry microbial pathogens that
can cause mild illness, such as gastroenteritis, to more serious illnesses, such as cholera and
dysentery (Environmental Protection Agency Office of Wastewater Management, 1996;
Environmental Protection Agency, 2017). Any untreated sewage can have serious pollution

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impacts to local waters in addition to causing thousands of illnesses each year (Environmental
Protection Agency, 2017).
There are numerous causes of
SSO events related to the integrity
of the sewer infrastructure.
However, the most common cause
of SSO events is pipe blockage
which is usually a result of fat, oil,
and grease (FOG) build-up in
sewer lines (Environmental

Figure 3: Design of outdoor gravity grease interceptors.

Protection Agency Office of Wastewater Management, 1996). Food service establishments
(FSEs) discharge FOG, as a result of preparing and serving food. The utility requires restaurants
to install and maintain FOG interceptor devices to prevent this commercial waste from entering
the wastewater collection system (Washington Suburban Sanitary Commission, 2016;
Environmental Protection Agency Office of Wastewater Management, 1996). Without these
devices, or if these devices are improperly maintained, FOG can build-up in sewer lines and lead
to pipe blockages, private backups, and SSOs. Both indoor and outdoor grease interceptors
utilize gravity to separate the FOG and solid particles in a large, underground “bin” from the rest
of the wastewater leaving the FSE (Figure 3). However, traditional FOG interceptor technology
is outdated and inefficient. The conditions inside these devices can be corrosive due to bacteria
build-up and decomposing organic material, which will very quickly destroy the metal structure
used in traditional grease interceptor design (Loucks, 2017). Higher levels of corrosion can result
from infrequent cleaning services, improperly managed repairs, acidity of food waste, poor
kitchen management practices, or any combination of these factors (Environmental Protection
Agency, 2017; Atlantic Pit Service Inc., 2009). Municipalities manage this problem through
regulatory compliance, but the lack of accountability and enforceability makes the infrastructure
management issue and higher compliance rates a challenge.
There are new, emerging technologies in grease trap and interceptor design, such as
epoxy-resin coatings, polyethylene “plastic” construction materials, and redesigns of the
structure of the device to increase grease capacity and reduce size (Loucks, 2017). These new
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technologies can solve many of the hard infrastructure problems of pretreatment programs, such
as frequent structure degradation, corrosion, and FOG bypass prevention (Loucks, 2017).
However, there is misinformation and confusion in the marketplace of these new technologies,
making it difficult for restaurant owners to accurately select the proper device regardless of
building materials (Loucks, 2017). Furthermore, municipalities struggle with soft infrastructure
management strategies to incorporate these technologies into their plumbing codes, ordinances,
and practice. The limitations of municipalities lie in the inability to make formal
recommendations on commercial products, and this requires a reexamination of the intersection
of hard and soft infrastructure management.
HARD AND SOFT INFRASTRUCTURE MANAGEMENT
Hard infrastructure includes anything related to physical infrastructure, such as roads or
sewer pipes, in contrast to soft infrastructure which relates to human capital or institutions which
create non-tangible, program-related “infrastructure” (Portugal-Perez, 2012). The physical
integrity of our sewers is closely linked to the health of our local environment, the people who
live and work in our communities, and the local values. Management of these physical systems
traditionally is established through regulatory mandates from the local government. Commercial
businesses play a role in contributing to this classic example of “The Tragedy of the Commons”,
often unknowingly contributing to sewer degradation and resource loss due to misinformation,
competing economic interests, and individuals maximizing their individual benefits (Hardin,
1968). Even at the time of Hardin’s “Tragedy of the Commons” fifty years ago, the conclusion
was similar to the sustainability principles of today; that a purely technical solution to the
complex problems associated with the commons would not be successful. According to Hardin,
addressing “The Tragedy of the Commons” requires “a fundamental extension of morality” and a
shifting of paradigms to include management philosophies and education of the users (Hardin,
1968). Following Hardin’s connection between the commons and global infrastructure, the
World Commission on Environment and Development (WCED) further evolved this idea of hard
and soft infrastructure integration in the report titled Our Common Future (Mei, 2009; World
Commission on Environment and Development, 1987). In this report, the idea of sustainable
development was combined with the concepts of hard and soft infrastructure to not only develop
technical solutions, but to also provide long-term, resilient management solutions (World

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Commission on Environment and Development, 1987). This set the stage for the future
development of integrated management and technical sustainability solutions, but a present-day
focus on solely hard infrastructure projects has left gaps in the literature of sustainable
infrastructure management.
Much of the literature agrees that infrastructure, both hard and soft, plays a critical role in
short-term and long-term economic development, human living standards, distribution of public
services, and environmental stewardship (Mei, 2009; Portugal-Perez, 2012; Ugwu, 2005;
Sterling, 2012). In addition, there is strong statistical evidence that supports the
interconnectedness of hard and soft infrastructure; that both the physical solutions influence the
success of the managerial solutions and vice versa (Portugal-Perez, 2012). However, there is
limited literature available that seeks to provide frameworks, or even examples, of successful
infrastructure management projects that incorporate elements of hard and soft infrastructure.
Many focus on a top-down, engineering-focused approach that continuously has limited the
associated frameworks because it doesn’t incorporate concepts such as equity, future-thinking,
and social context (Kibert, 2007). Challenges to this approach include measuring sustainability,
monitoring infrastructure and sustainability criteria, integrating practical solutions with morality,
maintaining market competitiveness, and aligning stakeholders to common outcomes (Sahely,
2005). From the perspective of a global environment, finding solutions to these challenges is key
to evolving the literature on infrastructure management. The current literature fails to consider
the success of local-level interventions on both hard and soft infrastructure, and how the
sustainability frameworks can play a role in developing new infrastructure management
frameworks that incorporate both hard and soft infrastructure principles. This project fills an
important gap in the sustainable development literature by providing a concrete example where
hard and soft infrastructure can be combined to achieve community sustainability, infrastructure
compliance, institutional resilience, and business equity.
RESOURCE RECOVERY
Wastewater management has historically used a “take, make, waste” approach to the
management of wastewater, water resources, and the associated waste byproducts (Glen, 2009).
In this approach, urban water management is perpetuating the unsustainable practice of a cradleto-grave resource life cycle. Limitations of this linear system approach include water resource
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stress, unsustainable resource consumption, environmental dispersion of highly concentrated
nutrients such as phosphorus, loss of energy rich waste resources, and financially unstable
utilities (Glen, 2009). Within the global energy context, limited resource availability has shifted
economic and societal systems to explore other options of renewable energy generation. This
includes the current push to include byproducts of the wastewater treatment process, including
FOG from pretreatment and sludge residuals from post-treatment, into the biotechnological
process of anaerobic co-digestion (Puyol, 2017).
Anaerobic co-digestion provides numerous opportunities and benefits for wastewater
treatment plants (WWTPs), such as reducing energy needs, diverting waste from landfill,
reductive detoxification of wastewater, water resource recovery from dewatered sludge, and
nutrient recovery (Jensen, 2017; Mata-Alverez, 2014; van Lier, 2008;). The feasibility of
utilizing FOG as an anaerobic co-digestion substrate is well documented at the WWTP in
Garching, Germany. The inclusion of FOG into the anaerobic co-digestion process increased the
efficiency of food waste digestion while lowering the cost of feedstock blending components
(Puyol, 2017). Externally from the digestors themselves, the cost of treatment savings from FOG
waste diversion greatly lowered the financial risk of the Garching WWTP utility (Puyol, 2017;
Mata-Alverez, 2014).
The biotechnologies to achieve this energy generation through waste digestion are available
to use and a lack of technological innovation is not the limitation to this systems intervention
(Puyol, 2017). Instead, the major challenge to this sustainability solution comes from resource
availability which stems from a variety of institutional barriers such as existing infrastructure,
utility governance, utility values, public and private infrastructure costs, enforcement structures,
and resource management (Glen, 2009; van Lier, 2008). Opportunities to improve institutional
infrastructure management directly connect to the ability of wastewater treatment plants and their
associated jurisdictions to overcome the barriers to anaerobic co-digestion and energy
sustainability.
Infrastructure and Sustainability
This project’s defining characteristic was its application of sustainability theories,
perspectives, and techniques to a complex, multi-stakeholder, infrastructure challenge. The
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importance of this project comes from identifying new, alternative pathways within wastewater
and extending the sustainability knowledge related to infrastructure management beyond that of
traditional regulatory models. Other sustainability research has not only identified infrastructure
as both a top issue related to global environmental progress and knowledge generation, but also
the most underutilized area for a sustainability approach (Mei, 2009; Sterling, 2012). While there
are frameworks and processes designed for engineers and by engineers regarding buildingspecific sustainable infrastructure, there are very few tools and examples for how to manage the
infrastructure from a regulatory perspective (Sahely, 2005; Ugwu, 2005). A more holistic
approach to infrastructure management would fill a global gap in the sustainability literature by
illustrating that sustainability principles can be applied to a local infrastructure challenge in order
to achieve a successful outcome. This project serves as an example within the sustainable
infrastructure literature that the sustainability competencies can identify, measure, and mitigate
the challenges associated with the intersection of environmental, social, and economic pressures.
A sustainability project is defined as integrating five core competencies: systems
thinking, anticipatory thinking, strategic thinking, normative thinking, and collaborative thinking
(School of Sustainability, 2017; Wiek, 2011). This project utilized these competencies to create a
comprehensive strategy for infrastructure management described below.
SYSTEMS THINKING
Traditional FOG infrastructure management involves an enforcement strategy that
focuses on the singular goal of replacing degraded infrastructure. There are missed opportunities
to engage businesses, community stakeholders, waste haulers, and local governments to create an
infrastructure system that is both practical and resilient. This project utilized a series of
stakeholder interviews and literature reviews to understand the indicators, stakeholders, and
variables that are most important in a sustainable infrastructure program. For example, the
inconsistency with waste hauler language disrupts the process of the system by creating
uncertainty in identifying the repairs and the associated urgency. This can cause delays, wrongful
repairs or replacements, unnecessary costs, and ultimately bypass and resource loss due to the
device not operating as designed. Identifying this systematic issue as an intervention point was
critical in creating the new Repairs and Compliance Program.

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The experiences of outside agencies as well as the internal experience of Tempe informed
this project on the best possible intervention strategy that could both work locally and can be
scaled up to other municipalities and applied to other sustainability initiatives. For example, the
financial assistance portion of this project was developed specifically for grease trap
replacements. However, the program structure was created with application to other
sustainability initiatives in mind, such as solar, grey water recovery, and low-use irrigation
systems. The “sustainability buy-in” model, where businesses or individuals must front costs to
participate in a sustainability solution, can be a barrier to most infrastructure-related challenges,
and this financial assistance model is intentionally applicable beyond just the TGC system.
ANTICIPATORY THINKING
Many of the TGC’s sub-programs required extensive future scenario planning to identify
any major unforeseen consequences that could disrupt or derail the resource recovery goal. For
example, the Vendor Registry was initially designed with the intention of being a subjective
evaluation process looking for exemplary service quality, business sustainability, and customer
service philosophy. This was to ensure that vendors would be vetted along the lines of
sustainability and business advocacy, with the intention of maintaining the trust between the
local government and the business members.
However, in the long-term this approach had the potential to incur great liability on the part
of the municipality that could result in the dismantling of the Vendor Registry and tarnish the
reputation of the TGC as a FOG management program. This would completely undermine the
FOG-to-Fuel model as the goal. Therefore, the future scenario planning process required that the
Vendor Registry take a more objective approach in the vetting process to minimize the city’s
risk. With this in mind, the objectiveness of the registry application was designed in a way that
sought the same principles of service quality, business sustainability, and customer service by
strategically asking specific questions and defining what would be the acceptable response or
responses. Another intervention point was to include a method by which member restaurants
could file incident reports in the event that a vendor demonstrated a failure to uphold the
principles of this program, which they agreed to as they joined. Through these methods, the
project was adjusted to the anticipation of possible negative future outcomes by designing more
strategic interventions today.
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STRATEGIC THINKING
The gaps in infrastructure management stated previously are problems found in the
majority of wastewater pretreatment programs. By creating a new model for infrastructure
management that uses a holistic approach a more sustainable future can be achieved.
For this project specifically, the use of knowledge gained during the process was used to
alter the final result to assure a more effective outcome from the proposed intervention strategies.
Originally, the idea was to create a Repair program for non-TGC members adapted from the
TGC Repairs and Compliance Program. However, the interviews with key stakeholders made it
clear that this intervention would have no effect on the outcome of infrastructure management
due to the nature of the inspection process. As mentioned before, non-TGC restaurants are
usually inspected once every seven years which means that any failing device discovered usually
requires a full replacement, and not just a simple repair. The intervention was redesigned to
reflect the needs and experiences of the stakeholders and to create a strategic solution that would
better suit their needs when replacing infrastructure: the FOG Resource Packet. It combined hard
infrastructure replacement processes with the educational strategies of the TGC to ultimately
created a positive outcome aligning with the overall sustainability vision.
NORMATIVE THINKING
As stated previously, the traditional infrastructure management model comes from a
linear perspective where FOG is considered a waste and infrastructure as merely a replaceable
part. Little emphasis is placed on the value of FOG as a resource, the importance of
infrastructure in its collection, and the partnership between business and government for the
common goal of environmental stewardship.
This project specifically has contributed to evolving this perspective in numerous ways.
First, the Infrastructure Assistance Program is the first of its kind to offer a financial assistance
package from a municipality that leverages the sustainable investment of city-allocated funds to
directly maintain the infrastructure of a waste resource for recovery efforts. In this way, the
program has eliminated the “sustainability buy-in” barrier to better align the values of businesses
and their regulators. This is the first step in changing the larger picture of environmental
regulation from an enforcement perspective to a partnership perspective. Secondly, the FOG
Resource Packet ties into changing the perspective of the enforcement process. By clearly
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illustrating through targeted education the importance of “The Commons” related to sewer and
the infrastructure maintenance processes, business values will shift to encompass a futurethinking strategy of a public good rather than the limited viewpoint of their own economic
bottom-line. Finally, in a more general sense, the very idea of putting emphasis on the
importance of infrastructure for resource recovery completely changes the role of a municipal
government. Instead of following the current paradigm of reactionary regulation, the role of local
government takes on a preventative strategy to advocate for private business infrastructure
protection to maximize collection of a resource. This changes the future of the environmental
regulation perspective to encompass greater sustainability ideals such as protecting the future
ability for communities to enjoy the benefits of clean water and clean communities.
COLLABORATIVE THINKING
Part of creating a successful sustainability project is the ability to communicate the endgoal across a variety of audiences and differing values. This project has relied heavily on the
ability to demonstrate the need for sustainability strategies within a political climate focused on
economic development. Specifically, there was an extensive review process across several
different departments and workgroups to integrate the proper language, philosophy, perspective,
and mindset into the programs; including Legal, Financial Services, Procurement, and Public
Works. Many of the concepts within the Infrastructure Assistance Program are subjective in
nature and follow a sustainability philosophy, such as service quality, equity, community
building, and future thinking. While these more subjective concepts work well in purely a
sustainability environment, the concepts needed adaptation with relevant city stakeholders in
order to communicate the outcomes and provide relevance to a broader audience. The goal
became to transform many of the program components to incorporate objectivity in the language,
such as defining a “TGC Vendor”, providing financial justification for the Grease Trap
Assistance Program, and incorporating the long-term goals of the Public Works Department.
In addition to the inter-department collaboration, this project required creating arguments
for sustainability to stakeholders focused almost exclusively on the economics. The importance
of reducing costs and increasing business value was critical to convincing the restaurant
community in Tempe that these programs not only accomplish city goals of sustainability but
also values their bottom-line requirements. For example, the development of the Repairs and
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Compliance Program relied heavily on the previous data from vendor repairs and conversations
with current vendors and compliance staff to determine the course of action, urgency, and on-site
management of repairs. Additionally, with the Grease Trap Assistance Program, conversations
with restaurant stakeholders were vital to creating the program design and justification for
allocation of city funds.
Applied Project Methodology
As mentioned above, the defining characteristic of this project is the application of a
sustainability perspective to a complex social, economic, and environmental problem. In this
type of project, the methods deviate from the traditional sense of an academic project to develop
pragmatic and relevant solutions for the stakeholders. The National Research Council has
defined applied projects methods as outside the normal methodology frameworks of
experimental or theory-seeking projects (National Academy of Science, 1983). Their definition
includes the importance of context-specific analysis in human-technology systems to optimize
the capabilities and performance of the system beyond the current state (National Academy of
Science, 1983). The limitations of applied methods include time, financial resources, and
freedom of action, which indicates that traditional experimental or theory-seeking projects
frameworks and methods do not have the suitable structures to answer the pertinent questions
within systems
development (National
Academy of Science,
1983). The significance
of this approach to the
project methodologies
is that this framework
connects specific
actions and pathways
with their critical
context and application.
Due to the dynamic
nature of applied
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Figure 4: Illustration of the applied project methods design, showcasing how each part
builds-on the next step in the process.

projects, parsing out a context-free methodology limits the understanding of the processes,
challenges, and alterations inherent to a long-term project (National Academy of Science, 1983).
Finally, this project needed to be adaptable to other utilities and their specific contexts. For this
reason, it was important to utilize a methodology that applied easy-to-follow steps and a
narrative of the entire process, including critical decision-making context. This was more
important to the project success than following a traditional, academic methodology.
In the original project charter, the methodology outlined a five-phase process centered
around deliverable development. However, this format did not accurately portray the methods
and their context for a holistic understanding of the project’s development. Instead, this project
followed more closely the methods of the National Research Council’s approach to applied
methodology, which are categorized into five distinctive, steps (Figure 4): analysis, identification
of needs, data collection, prediction, and evaluation (National Academy of Science, 1983).
ANALYSIS
Analysis, under Applied Project Methodology, is the stage to gather information on the
current state by performing information and system analysis (National Academy of Science,
1983). The analysis section of this project derived from the use of an extensive literature review
of the current state. This included an examination of literature related to pretreatment regulation,
pretreatment technology, FOG, resource recovery, and infrastructure management. Finally, a
literature review of other municipal aid programs related to FOG and infrastructure was
conducted to identify the limitations of other attempts to address this problem. This included
reviewing preferred pumping programs, financial assistance models, and vendor vetting
processes. The major limitations of these programs, which sparked the conceptualization of the
Infrastructure Assistance Program model, were narrowness in scope, minimized equity, longprocurement timelines, and little to no emphasis on restaurant education.
The second-portion of this literature review sought to understand the current state specific
to the TGC and City of Tempe Environmental Services as part of a Function or Task Analysis
defined by the Applied Project Methodologies (National Academy of Science, 1983). In this
portion, informal conversations with Environmental Services staff, vendors, and restaurants in

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addition to workflow examinations, operations observations, and on-site experiences began to
identify the current state of the existing soft infrastructure.
IDENTIFICATION OF NEEDS
In the Identification of Needs step, the researcher uses an interview or survey method to
gather information about stakeholder needs and relevant intervention points (National Academy
of Science, 1983). The methods used for the Identification of Needs utilized the approach of
developing a stakeholder survey and interview process. A questionnaire asking strategic
questions regarding hard and soft infrastructure management was created to be distributed to key
Environmental Services staff, this built-upon the information gathered during the Analysis step.
The questionnaire asked questions related to organizational structure, institutional relations,
workflow data, and program recommendations. Participants could opt-in to have the
questionnaire asked in an interview process with the default process being to individually fill-out
the questionnaire. The information was collected after a two-week period and compiled into a
matrix that disassociated the identities of the participants from their answers. Each participant
was given a randomized number assigned with their answers for the remainder of the project.
After the data collection and compiling it into the response matrix, key concepts, phrases, and
trends were identified.
DATA COLLECTION
Data Collection refers to the compiling of information from the previous two stages and
an application of the knowledge, trends, or models developed thus far (National Academy of
Science, 1983). Information from the Analysis stage and the Identification of Needs stage was
organized to understand the stakeholder needs for the new Repairs and Compliance Program.
Interview information, previous repair data, vendor stakeholder conversations, and restaurant
owner feedback were integrated into the model following a common-repair list. In this redesign,
a list of the most frequent “common” FOG device repairs were compiled. Then, based on vendor
recommendations, each repair related to the proper urgency, response time, and repair technique.
After a review process by Environmental Service Compliance Staff and TGC vendors, the new
Repairs and Compliance Program underwent an Activity Analysis (National Academy of

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Science, 1983), or beta-testing, to test the new intervention as a coupled soft-hard infrastructure
process.
The original drafts of the Vendor Registry and Grease Trap Assistance Program (GTAP)
programs developed before the drafting of this project scope. These drafts were reexamined with
the objective to look for opportunities to create intervention points to address gaps identified in
the previous steps. After identifying the first two categories of vendors that would be on the
registry, industry-specific qualifications were identified through a review of FOG technology
requirements, business certifications, and industry expert knowledge.
PREDICTION
The Prediction stage takes the previous step’s application and uses future-scenario
planning tools to consider any risks or unforeseen consequences with the interventions (National
Academy of Science, 1983). Next, the new Vendor Registry applications were drafted to include
the subjective processes from other preferred pumper programs, although modified for two
specific vendor categories: (1) Manufacturers of devices and (2) vendors capable of making the
necessary repairs or installing new devices. These documents underwent an extensive legal
review process to transform much of the subjective structure to a more objective process, such as
language, application questions, and program expectations. This process highlighted the areas
where the Vendor Registry did not align with the future-state or potentially could lead to
unforeseen consequences in the future state.
The GTAP program design was developed during this time to incorporate different
aspects of other FOG financial assistance programs and the stakeholder needs of the TGC.
GTAP also underwent extensive internal review process and was altered to reduce future risk.
GTAP funding opportunities were explored and these included non-profit grant programs,
federal funding grants, city budget supplementals, and city award funds. Federal funding, which
was the preferred choice, was not available given the administration’s priorities and legislation.
Ultimately, both a city budget supplemental and an application for a city-funded innovation grant
were submitted.
Interview data from stakeholders in the Analysis step altered the course of the
deliverables and process in this portion of the project. Stakeholder information illustrated a need
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for more restaurant outreach and education strategies rather than another infrastructure
replacement process. Outreach strategies from TGC experience, staff recommendations, and
restaurant requests were combined into a FOG Resource Packet designed to educate restaurants
on the infrastructure replacement process. Additionally, based on literature review findings and
stakeholder interviews, two program recommendations were drafted for Environmental Services
and TGC managerial staff. These included future-vision methodologies based on current
intervention needs outside the original scope of the project, which were the incentivization of
plastic trap materials and automatic enrollment of new-build restaurants into the TGC.
EVALUATION
A defining feature of the Applied Projects Methodology is its consideration for the ongoing evaluation and improvement process in the application of information and processes to
systems interventions (National Academy of Science, 1983). This allowed the room for growth
within this project as it worked through the drawn-out process of government review. This
project conducted its own Evaluation process through the reviews and expertise of the Public
Works, Legal, Financial, and Procurement city departments. Through their feedback and industry
knowledge, adjustments were made to the project deliverables to encompass a more thorough
checklist of stakeholder needs. Additionally, test plans for the Vendor Registry and GTAP were
crafted upon the completion of the review process and approval of key Tempe personnel.
Finally, all documentation relevant to software development and the Infrastructure
Assistance Program were compiled and given to the software development team. This included
standardizing formatting to ensure the best assimilation into the future software automation of
components of the Infrastructure Assistance Program. There were several meetings with the
software vendor to ensure that the needs of the Infrastructure Assistance Program and TGC were
aligned with the visioning of the software program.
Findings
CURRENT STATE LIMITATIONS
From the questionnaires, interviews, and research, three main gaps were identified in the
existing program, which were organized into a project approach that consisted of three combined
deliverable phases, respectively. The first gap identified is that there was a concern from TGC
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staff regarding the equity of TGC members in comparison to non-TGC restaurants when
replacing or repairing FOG infrastructure. While there is some leniency in the timing
requirements for TGC members to get their traps repaired or replaced if it does appear to cause
significant harm to the sewer or operational issues within the restaurant, there is no ability to
show discretion and provide leniency to let a failing device be unaddressed indefinitely. As a
result of this, it became clear that the intervention point would have to instead ease the process
for TGC members and provide a clearer internal process for city staff to enforce quickly with
restaurant advocacy in mind. This resulted in the conceptualization of a multi-faceted
Infrastructure Assistance Program that would both ease the process from a technical, financial,
sustainability perspective (See Figure 5).
The second gap identified was that the existing workflow for identifying repairs in TGC
members was inconsistent, inefficient, and did not value the partnership approach that is core to
the TGCs foundation. Additionally, the previous workflow was time consuming, lacked concrete
accountability, and did not coordinate with the stakeholders of the TGC. The intervention point
at this gap was to reconstruct the existing workflow into a comprehensive Repairs and
Compliance Program of the TGC that was both fair to the members, and efficient and effective
for city staff. Additionally, it had to ensure that repairs and replacements would happen as
quickly as possible.
The third gap
identified was that the repair
and replacement process for
non-TGC members was not
reflective of stakeholder
needs, including education
and advocacy. The existing
process was slow, sometimes
taking up to a year or two to
replace a failing device,
inconsistent, and errors due to
miscommunications were
common which led to
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Figure 5: Representation of the new Infrastructure Assistance Program
structure within the Tempe regulatory model with the associated subprogram components.

restaurants once again replacing infrastructure at their expense. It was determined that the most
efficient intervention point to address this gap was to create an education document to assist
business-owners through the replacement process.
PROJECT DELIVERABLES
The findings of the literature review and research resulted in a series of deliverables that
make up the various intervention points determined to help the program reach its future vision.
Below is a list of the deliverables, as well as the definition, objective, and outcome or outcomes
of each.
Program Recommendations
DEFINITION: The Program Recommendations is a memorandum document written to
Environmental Services managerial staff to provide two additional intervention points that align
with the future-vision and strategic priorities outside the scope of this project: the institutional
incentivization of plastic devices and the automatic enrollment of new-build restaurants into the
TGC.
OBJECTIVE: The objective of this deliverable is to provide all possible intervention points to the
client that address the hard and soft infrastructure gaps identified during the Analysis. The
recommendations were crafted based on the literature review of gaps in the larger industry so as
to better contribute to the scalability of this project and the program.
OUTCOMES: The outcome of this deliverable is to provide a recommendation for future
strategies to continue to evolve the IAP and TGC vision to better align with the sustainability
goals.
FOG Resource Packet
DEFINITION: The FOG Resource Packet is a document utilizing educational strategies to outline
the FOG infrastructure replacement process for restaurants and to educate owners on FOG
management through a Best Management Practices (BMP) strategy.
OBJECTIVE: The objective of this document is to provide a comprehensive, educational tool for
restaurant owners, both TGC and non-TGC, to better understand the replacement process.

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Additionally, it continues to support the public-private-partnership model of creating new
municipal relations with private businesses and promoting an understanding across the common
goal of environmental stewardship. The other objective is providing Environmental Compliance
Staff with a single point-of-information about device replacement, rather than the current, piecemeal process.
OUTCOMES: The outcome of this deliverable is to streamline the restaurant communication
process by incorporating principles of education, advocacy, and partnership. In conjunction with
this, the outcome to reduce inspection staff time spent reexplaining the replacement process to
restaurants or fixing incorrectly permitted, sized, and/or installed devices.
Repairs and Compliance
DEFINITION: The Repairs and Compliance Program is a sub-program of the TGC that
encompasses monitoring device condition, coordinating repair vendors, communicating
infrastructure needs to member restaurants, and providing compliance assurance with city
plumbing code.
OBJECTIVE: The objective of this program and its new workflow process is to provide long-term
resilience to the intersection of TGC advocacy principles and Tempe compliance requirements to
model a hard and soft infrastructure approach. More specifically, this includes reducing the extra
time spent by inspection staff tracking down repairs and replacements, confusion in the
communication between Tempe and its vendors, and better outlining the pathways towards
compliance for restaurants.
OUTCOMES: The outcome of this sub-program redesign is a more comprehensive internal
compliance process for the TGC that encompasses principles of hard and soft infrastructure
management. The future-vision of maintaining infrastructure sustainability for the goal of
resource recovery and better soft infrastructure management strategies is best encapsulated in the
use of the industry-standardized common repair list in this new program design.
Vendor Registry
DEFINITION: The Vendor Registry is a list of non-contractual, grease-related services and
vendors selected by and exclusively for the TGC as a resource for members to address issues
outside the normal pumping and cleaning. This includes a set of applications based on chosen
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vendor categories, objective vetting processes based on application responses, and the online
access for member restaurants to find high-quality, consistent grease-related services.
OBJECTIVE: The objective of the Vendor Registry is to provide an alternative pathway for
vendor procurement that does not rely on the traditional, contracted procurement processes. This
better aligns the TGC processes with the service of member restaurants to find high-performance
vendors to repair, upgrade, or replace their plumbing infrastructure. The Vendor Registry is one
of the two components of the Infrastructure Assistance Program, which has the overall objective
of addressing the inequity associated with current TGC infrastructure repairs and replacements.
OUTCOMES: The outcomes of the Vendor Registry build upon the need to incorporate hard and
soft infrastructure strategies. From a hard infrastructure perspective, this program provides
access to the vendors who will perform the repairs, upgrades, and replacements properly and in
compliance with city-code. From a soft infrastructure perspective, the Vendor Registry continues
to utilize the strong relationships with Tempe and vendors to achieve common goals related to
infrastructure and environmental stewardship.
Grease Trap Assistance Program (GTAP)
DEFINITION: The Grease Trap Assistance Program (GTAP) is a revolving fund to help creditworthy businesses spread the cost of grease trap upgrades over one or two years by offering zeropercent interest loans at the same rate that previous loans are paid back to the city. This utilizes a
revolving fund model to more sustainably leverage a one-time investment of $60,000 in city
funds to pilot this project.
OBJECTIVE: The objective of GTAP is to balance the inequities between TGC and non-TGC
members due to higher levels of scrutiny which create a higher frequency of repairs and
replacements for TGC members. Currently, there are 10% - 15% of restaurants that require full
trap replacements which would not have been identified outside the TGC. GTAP is the other
component of the Infrastructure Assistance Program, which has the overall objective of
addressing the inequity associated with current TGC infrastructure repairs and replacements.

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OUTCOMES: The outcomes of GTAP are estimated to be the disbursement of $4,000 in new
loans each month which could replace one to two grease traps per month with approximately a
minimum balance $10,000 sustained in the fund account. With these estimates, GTAP could
replace 20 failing grease traps per year and encourage more enrollment in the TGC by removing
the cost barrier to restaurants with degraded infrastructure.
Overcoming Project Challenges
Throughout this project, there have been a few challenges to the original design of the
Infrastructure Assistance Program that required different solutions to overcome. First, funding
for GTAP was originally going to come from federal grant money through EPA Region IX.
However, due to uncertain Congressional funding for the EPA grant programs and government
shutdown in January, this path was no longer feasible within the scope of the project. Next, the
client and myself decided to fund the program through a City budget supplemental rather than
wait for federal funding to become available. This led to another set of reviews highlighting a
need for a smaller scoped program pilot before more money would be set aside. Therefore, a new
funding source was recommended to myself which was The Innovation Fund Award. As part of
the client deliverables, the program was designed for the Innovation Fund Award application and
submitted to City Council. The new amount we asked for was $60,000 to start the pilot program.
Second, the governmental review process became one of the major limitations to project
implementation. The research, design, and content creation of the project moved with ease
during the beginning phases of the project. However, including collaboration across several
different city departments proved to greatly slow down the project momentum and delay
program implementation. The best approach to overcoming this challenge was to remain
strategic, persistent, and patient in instituting the changes of the various stakeholders. For
example, the internal review process proved to be longer than previously determined and
prevented the original timeline for implementation. To overcome this, the core evaluation
metrics for vendor quality were kept constant but the strategy (i.e. subjective versus objective) by
which the program sought that information was altered to satisfy the requirements of city
programs.

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Third, the methods by which gaps in the program were identified was altered from the
original design of the project charter. Originally, the intended model was to utilize an
Institutional Analysis of internal processes to illustrate where deficiencies in the current system
may arise. This proved to not be a good fit for the nature of the stakeholder feedback and system
representation. Instead, the better model became a Trend Analysis (National Academy of
Science, 1983) to highlight the key concepts, gaps, limitations, and stakeholder needs from both
the literature review and the interviews. This better demonstrated the critical external system
context while not limiting the internal needs of relevant stakeholders. For example, the FOG
Resource Packet was a direct result of the Trend Analysis approach. Stakeholders identified that
non-TGC device maintenance could rarely encompass a repair process due to the lengthy reinspection process. The best option by the time failing non-TGC devices are discovered is to
replace the entire device. Stakeholders explicitly identified a need for restaurant education
strategies and not a repair program for restaurants outside the TGC. Due to this measurable data
trend of non-TGC device failure and stakeholder knowledge, which could not accurately be
represented in the graphical approach of an Institutional Analysis, the FOG Resource Packet was
developed utilizing TGC educational strategies around FOG, device replacement, and
infrastructure maintenance.
Conclusions
The health of our sewer systems is rarely a component of sustainability that comes to mind
when discussing environmental, human, and economic longevity. We often take for granted the
infrastructure, resources, and people that spend their time working to make sure our communities
are clean and free from contaminants. When infrastructure degrades, not only is harmful bypass
affecting our environment but we are also losing a resource that has the potential to change local
renewable energy solutions. Degrading wastewater infrastructure will always be a problem that
requires a more comprehensive solution than merely replacing pipes and fighting the neverending battles of traditional enforcement. This project has illustrated that by providing the tools
to restaurants and local businesses, FOG resource recovery and higher compliance rates are
possible through a sustainability model.
By providing the tools for community businesses to maintain their infrastructure long-term,
the issue of infrastructure degradation can be addressed with both a hard and soft infrastructure
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approach which fulfills a gap in the current sustainable infrastructure literature. Through a
comprehensive approach to infrastructure assistance, including internal administration, funding,
and external partner messaging, this program can cultivate a community where sewer health,
environmental longevity, and resource recovery are local values and shift the paradigm from
enforcement to partnership.
Future Directions
Future students have many opportunities for further exploring the gaps in the sustainability
literature related to infrastructure and infrastructure management solutions, such as: How can
local infrastructure management solutions be scalable? What are the challenges and limitations to
the regionalization of both hard and soft infrastructure sustainability?
Additionally, with a specific focus on FOG, more attention needs to be paid to the
physical design of grease traps and interceptors. This could include a comprehensive review of
certification requirements and the subsequent inconsistencies in this current model. Students
should focus on questions such as: How can hard infrastructure code be standardized across
neighboring municipalities and even regions? What changes to grease trap and interceptor design
would best support resource recovery, keeping in mind the issue of degradation?

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Photo References
Figure 1: (City of Tempe, 2017)
Figure 3: (Atlantic Pit Service Inc., 2009)
Figure 4: (National Academy of Science, 1983)

Acknowledgements
This project would not have been possible with the support and encouragement of the City of
Tempe Environmental Services and Tempe Grease Cooperative Staff: Cassandra Mac, David
McNeil, Richard Dalton, Annika Andersen, and Alyssa Siqueros.
Thank you for taking the time and effort to not only believe in the project vision but also in my
ability to complete it. The next happy hour is on me.
I would also like to thank my parents for their never-ending love and support for all my crazy
ideas and academic pursuits. Unfortunately, I can make no promises that this is the last one.

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