Zero-Waste Program Success: A Systems Approach to Indicators at the Micro, Meso, and Macro Levels

Abstract

Existing sustainability tracking frameworks primarily address water, energy, and material durability, with limited focus on factors driving zero-waste (ZW) initiatives. The current sustainability tracking tools especially lack comprehensive assessment mechanisms to evaluate organizational progress toward ZW, especially in higher education institutions (HEIs). This study reviews the global literature (2000–2023) on ZW indicators in organizations, focusing on HEIs, using databases such as Scopus and Web of Science, with an emphasis on waste reduction and sustainability practices. Institutional theory is used to explain the adoption of ZW programs in HEIs through normative, mimetic, and coercive isomorphisms. This study finds that ZW initiatives in HEIs are driven by shared professional norms (normative isomorphism), imitation of best practices (mimetic isomorphism), and compliance with regulatory policies (coercive isomorphism). Education, full-time staff, sustainability offices, and student advocacy play key roles, while collaboration within sustainability networks further enhances these efforts. This study emphasizes the complex interplay of these isomorphic forces across different levels of influence.

1. Introduction

Population growth, industrialization, urbanization, economic growth, and overconsumption are causing increased waste generation globally, particularly in the United States (US), where per-capita material consumption and waste production are the highest [1]. Due to the increasing waste, sustainable consumption and waste production have gained significant attention, which can be seen by the addition of Sustainable Development Goal (SDG) 12—“Responsible Consumption and Production” to the list of 17 SDGs in 2015, with a goal of achieving it by 2030 [2,3].

Some of the aims of this goal focus on implementing a 10-year sustainable policy framework and reporting systems to track progress toward responsible consumption and production, halve the global per capita food waste by 2030, reduce waste generation through prevention, reduction, recycling, and reuse by 2030, and ensure companies adopt sustainable practices and reporting frameworks [4]. Following these aims, communities, organizations, and institutions, including higher education institutions (HEIs), are implementing various zero waste (ZW) programs and frameworks as part of their sustainability goals to reduce their environmental impact and waste generation while increasing resource efficiency. ZW plans are strategic plans aimed at eliminating waste through resource conservation, waste reduction, and the promotion of recycling and reuse. Typically, ZW plans are structured to reduce waste sent to landfills and incinerators by diverting materials back into the economy through recycling, composting, and product redesign, with a focus on investing in upstream waste diversion efforts such as redesigning products to minimize waste, reducing consumption needs, and maximizing the reuse of existing materials [5]. They also focus on collaboration with various stakeholders, such as local governments, businesses, and communities, to foster sustainable waste management practices [6].

The literature on the factors promoting the circular economy (CE) usually divides these factors into micro, meso, and macro levels when studying organizations, mostly businesses, and industries [7,8,9,10,11]. However, there is limited literature that helps understand the organization and applicability of these frameworks and their reporting systems in promoting ZW in HEIs. The present sustainability frameworks predominantly focus on issues related to water, energy, and material durability, with less attention dedicated to identifying the factors that facilitate the achievement of ZW. Some studies have explored the economic dimension of waste, recognizing that waste incurs direct costs from production to disposal and indirect costs resulting from environmental damage and impacts on human health [12]. Others have linked waste to societal challenges, particularly the correlation between population growth and increased waste generation [13]. However, existing frameworks generally do not integrate the complex interactions of social, economic, political, and other underlying factors that influence ZW initiatives. Consequently, they do not offer a comprehensive understanding of activities that can effectively reduce waste at its source, including waste prevention through educational initiatives or hiring more employees. Therefore, while existing sustainability tracking systems like the Global Reporting Initiative (GRI) and Association for the Advancement of Sustainability in Higher Education (AASHE) contribute to monitoring the overall sustainability performance of HEIs, there is a need to develop assessment tools specifically tailored to gauge the progress in achieving ZW.

Additionally, it should be of interest to study the progress and motivations of HEIs because these institutions often mirror the governance and municipal structures of cities [14]. However, while HEIs are similar to cities, they also hold a unique status in society as education hubs. Through partnerships with local governments, businesses, and community stakeholders, HEIs conduct applied research that demonstrates sustainable practices in real-world contexts, further advancing their educational missions. For instance, initiatives such as implementing waste diversion programs, piloting renewable energy projects, or developing community-centric sustainability strategies highlight the role of HEIs as living laboratories for innovation and leadership in sustainability. Achieving any goal and making progress toward it in such institutions depend on the commitment of the entire organization, including its individual members. This collective sense of belonging, or the “social identity” shared by the organization and its members, differentiates the governance structure of HEIs from that of cities [15]. It also means that progress toward sustainability is not only dependent on the collectiveness or differences among the social groups inside an HEI but also on such differences from the physical and social structures in which the HEI is embedded. Similarly, HEI’s sustainability policies will also be impacted by political and economic factors, inside and outside the institution. Therefore, studying these institutions is important due to their complex nature and their significant potential to influence society on a larger scale.

This paper will provide a categorization of zero-waste programs at colleges and universities using the concept of systems hierarchy. Such a categorization will help the conceptualization of a framework for ZW systems in organizations, as well as provide an opportunity to classify new indicators.

2. Conceptual and Theoretical Background—Systems and Institutional Theory

Systems theory was used to organize the factors being studied in a multi-level framework at the micro, meso, and macro levels. These levels draw from previous studies on CE indicators [10,11,12,16,17,18], which help contextualize how ZW practices are adopted within organizations, including HEIs.

At the micro level, indicators focus on internal processes within HEIs, such as operational efficiency, waste diversion efforts, and goal-setting for sustainability. This is influenced by CE studies where micro-level indicators assess the efficiency of products and processes within organizations [15,16]. In HEIs, these factors include initiatives like setting ZW goals or implementing waste reduction programs, which are under the direct control of the institution.

Meso-level indicators of the CE focus on industrial symbiosis, where organizations form networks to share resources, infrastructure, and by-products [9]. In organizational studies, the meso level refers to interactions between organizations, shaped by shared understandings and rules within a domain [19]. These interactions can involve the exchange of goods, services, and knowledge about norms and standards [20]. When applied to HEIs, the meso level involves collaboration between HEIs or between an HEI and other entities, like city governments or reuse centers, to achieve common goals. For instance, the Ohio State University collaborated with Rutgers University and the city of Columbus to launch a pilot food waste reduction campaign in the city of Columbus [21]. These universities are helping create educational material on food waste reduction to raise awareness and understand the food waste in the community, helping the city refine its food waste reduction strategies. The campaign is assessing existing efforts, identifying best practices, and creating a scalable model for other municipalities to follow. Similarly, Iowa State University’s Polymer and Food Protection Consortium collaborated with industry partners to develop sustainable solutions for single-use plastics and agricultural by-products. Key projects included bio-based foam with HNI Corporation, plant-based adhesives with the American Packaging Corporation, and repurposing single-use plastics and fly ash with the city of Ames [22].

At the macro level, larger-scale indicators are examined, focusing on policies and practices at the regional, national, or international level. Macro-level factors are less within the control of individual HEIs but are influenced by broader regulatory environments and public policy on sustainability [18]. For HEIs, this might include compliance with state or national sustainability mandates or participating in international sustainability networks.

In this study, the HEI is the unit of analysis (Figure 1). The micro-level factors are the factors that occur inside the HEI and are under great direct control by the HEI, such as setting a ZW goal. Meso-level factors focus on collaborative efforts between two HEIs (e.g., HEI A and HEI B) or between an HEI and a local entity. These collaborative endeavors involve direct control by the HEI, albeit to a lesser extent compared to micro-level factors, as decisions made by other involved organizations can also impact the outcome. Lastly, at the macro level, larger-scale factors come into play at the municipal, state, or national scale, which are elements that are beyond the control of an HEI.

While systems theory provides a useful framework for categorizing these multi-level factors, it does not directly explain the organizational motivations for adopting ZW programs. To address that, this study draws on institutional theory (IT), which provides insights into why organizations, such as HEIs, adopt certain practices, including sustainability initiatives. IT posits that organizations face pressures from both internal and external sources that drive them to adopt similar practices to survive and gain legitimacy. This process, known as isomorphism, can occur in three ways: coercive, mimetic, and normative [23].

Coercive isomorphism arises from formal pressures, such as regulations or governmental policies. HEIs might be compelled to adopt ZW programs to comply with state or federal environmental laws or to secure funding linked to sustainability performance [24]. Coercive isomorphism ensures that organizations meet external expectations, particularly from authorities, to avoid penalties or gain access to resources.

Mimetic isomorphism occurs when organizations imitate the successful practices of others, especially in situations of uncertainty. HEIs may adopt ZW programs by emulating other universities that have successfully implemented such initiatives. This imitation is often driven by the desire to improve performance and achieve similar success without necessarily testing the methods first [23]. For instance, HEIs participating in sustainability networks, such as the AASHE, may replicate successful practices from peer institutions [25,26].

Normative isomorphism stems from professional standards and expectations. HEIs often adopt practices like ZW initiatives due to pressures within the academic community or sustainability profession. For example, sustainability managers or faculty members, influenced by their professional networks or training, may advocate for the adoption of ZW policies within their institution as part of a broader commitment to sustainability goals [23]. In this context, HEIs may feel compelled to implement climate action plans or ZW programs to align with the norms of peer institutions and maintain their legitimacy within the academic and sustainability communities. These organizations do not have to “legally” adopt a climate action plan, but they do so because other HEIs are taking that step to maintain their social recognition and “legitimacy”. According to IT, legitimacy refers to the extent to which an organization’s actions, practices, or structures are seen as acceptable, appropriate, and valid by external stakeholders, including the broader society, customers, investors, regulators, and other organizations [23]. In that regard, when adopting climate action plans, members of HEIs feel their institutions are coming to be socially accepted and recognized by other HEIs since they are taking similar actions to those expected of a typical HEI in the US. Figure 2 provides a graphical representation of these three isomorphisms using the example of HEIs.

Isomorphisms thus account for why organizations might adopt ZW or other programmatic goals. Whether by coercion, mimesis, and/or normative reasons, organizations may choose to pursue ZW or other goals. Systems theory helps to structure the factors influencing ZW adoption in HEIs across multiple levels, from internal processes to external policies. Institutional theory, in turn, offers insights into why HEIs might adopt ZW programs, highlighting the role of coercive, mimetic, and normative pressures. Together, these frameworks provide a comprehensive understanding of how ZW initiatives in HEIs are influenced by both internal decision-making and external pressures.

3. Research Methodology

This study undertakes a comprehensive review of the existing literature to classify and analyze the current indicators used in assessing ZW initiatives in organizations, with a particular focus on HEIs.

The literature search was conducted using multiple academic databases, including Google Scholar, ProQuest, and Web of Science, from 2000 to 2023, to ensure a broad coverage of relevant studies. The search terms used on Google Scholar were (“zero waste implementation” OR “zero waste strategies” OR “waste reduction initiatives”) AND (“higher education institutions” OR “colleges” OR “universities”) AND (“landfill diversion” OR “composting” OR “source separation” OR “behavioral interventions” OR “recycling” OR “circular economy”). The key words provided a list of 455 studies, out of which the highest number of studies (73) was conducted in year 2023, as shown in Figure 3. Web of Science listed only 2 articles, and Proquest generated a list of 21 full-text and peer-reviewed articles with the same keywords, all of which were available on Google Scholar.

Studies that focused on the general waste management process of an HEI, waste management plans, gray literature, web articles, and those irrelevant to factors or indicators of waste reduction, diversion, and minimization in cities, businesses, HEIs, and other organizational settings, as well as those published in languages other than English, were excluded from this study. The remaining studies were then reviewed to extract key themes related to waste reduction, diversion, and minimization in HEIs, municipalities, or businesses, ZW, the circular economy or sustainability indicators for HEIs, municipalities, or businesses, factors increasing success of program implementation at the micro, meso, or macro level, and factors affecting program implementation in relation to institutional theory.

The review covers studies conducted across all continents, although the majority of the literature is concentrated in the US, Canada, UK, Australia, and European nations, as can be seen in

Table 1. Count of papers per country.

US	106
Canada	30
UK	12
China	11
Australia	7
India	7
Turkey	6
Brazil	6
Ghana	5
Malaysia	5
Thailand	5
Saudi Arabia	5
Poland	4
New Zealand	4
Mexico	4
Sri Lanka	4
Philippines	3
Portugal	3
Sweden	3
Indonesia	2
Hungary	2
Italy	2
France	2
Kenya	2
Bangladesh	2
Germany	2
Tajikistan	2
Japan	2
Iran	2
Qatar	2
Colombia	2
Spain	2
Costa Rica	1
Finland	1
UAE	1
Nigeria	1
Lithuania	1
Norway	1
Singapore	1
Belgium	1
Cambodia	1
Estonia	1
Kuwait	1
Iraq	1
Nepal	1

. It is important to note that the table only includes countries that were identifiable through VOSviewer (https://www.vosviewer.com); countries that could not be extracted are not represented. Nonetheless, the overall trend indicates that the United States accounts for the highest number of studies. This geographic distribution reflects the greater prevalence of sustainability policies and zero-waste initiatives in these regions.

Table 2. Summary of studies included in this paper.

Major Concepts	Micro	Meso	Macro
ZW/sustainability plans	Tchobanoglous et al., 2022 [27]; Sherburne, 2019 [28]; Lidstone et al., 2015 [29]; Alexandra Wright, 2006 [30], McNamara, 2010 [31]; Locke and Latham, 1990 [32]; Lingard et al., 2001 [33]; Zhang et al., 2011 [34];
Procurement policies	Ayarkwa, 2011 [35]; UCLA, 2021 [36]; SB 54, 2022 [37]; ESF guidelines [38], Lisle, 2020 [39]
Education and training	Zachariou, 2008 [40]; Ebrahimi and North, 2017 [41]; Brody and Ryu, 2006 [42]; Angelaki et al., 2024 [43]; Moqbel et al., 2020 [44]; Kaplowitz et al., 2009 [45]; Leal Filho, 2024 [46].
Communication	Dahle and Neumayer, 2001 [47]; Mason, 2003 [48]; Wu, 2018 [49]
Funding/Incentives	Dahle, 2001 [47]; Pitcher, 2010 [50]; Cheung, 2015 [51]		Allen, 2012 [52]
Presence of sustainability office/committee	Ebrahimi and North, 2017 [41]; Levy and Marans, 2012 [53]; Filho, 2015 [54]; Velazquez, 2006 [55]; Shi and Lai, 2013 [56]; Filho et al., 2019 [57]
Community engagement and collaboration		Kezar and Bernstein-Sierra, 2019 [58]
Sustainability advocacy		Filho et al., 2019 [57]; Peer and Stoeglehner, 2013 [59]; Moore, 2005 [60]; Alshuwaikhat and Abubakar, 2008 [61]; Mosier and Ruxton, 2018 [62]; STARS (2019); Gardner, 2021 [63]
Regulatory and legal frameworks			Hong (1999) [64]; Allen, 2017 [65]; Liyanage, 2019 [66]; Zaman and Lehmann, S., 2011 [67]; CalRecycle, 2023 [68]; USC, 2023 [69]; Latif, 2020 [70]; Schmidt and Rocconi, 2021 [71]; Henkels, 2022 [72]; NCSL 2020 [73]; Wilson, 2012 [74]; EPA, 2021 [75]
Infrastructure	Fuentes, 2022 [76]		Hao et al., 2020 [77]
Technological advancement			Murphy and Pincetl, 2013 [78]; Rubicon, 2023 [79]; Shreyas Madhav, 2022 [80]

below summarizes the major studies included in this study on the basis of the major concept and whether occurring in micro-, meso-, or macro-level settings.

4. Results

The existing literature underscores the significance of several factors across different levels of analysis, as delineated by systems theory. This review organizes those factors into micro, meso, and macro levels and institutional characteristics. At the micro level, a broad spectrum of the literature underscores the critical role played by factors such as education, funding, well-defined ZW plans, procurement policies, the employment of dedicated personnel, the establishment of sustainability offices, and the effective communication of initiatives. At the meso level, an emphasis is placed on active participation in sustainability networks and advocacy groups. At the macro level, the prevailing themes center on policy considerations at various governmental levels as pivotal elements in the progression toward ZW goals. Lastly, the institutional characteristics, such as being public, private, doctoral, or an associate (two-year) HEI, are kept in a separate category as they do not clearly fall under this study’s definition of micro, meso, or macro level.

4.1. Micro-Level Factors

Micro-level factors encompass internal HEI dynamics such as ZW/waste management/sustainability plans, funding, full-time employees, and infrastructure—all critical for successful waste management [27,28,29]. An environmental plan or sustainability plan is deemed important for an HEI to establish tangible actions and timelines to move toward sustainability, ensure that all the activities conducted within the HEI align with the guidelines outlined in the sustainability plan, facilitate effective communication of key goals, and inspire individuals to commit to sustainability [30,81]. ZW goals are increasingly becoming a key component of HEIs’ sustainability and environmental plans. However, academic research on these specific goals remains limited, with most studies focusing on broader sustainability or environmental initiatives, but similar conclusions for the presence of ZW plans in HEIs can be expected. According to AASHE, the tangible, measurable goals and objectives in a sustainability plan can allow HEIs to track their progress, document their successes, and manage the resources required to attain sustainability [82]. McNamara, in their study [31], found that HEIs achieve greater sustainability progress when they have a written sustainability plan that outlines specific goals, assigns clear individual responsibilities, includes a timeline, and establishes a process for measuring progress. The importance of having a ZW plan with clear, measurable, and aspirational objectives aligns with goal-setting theory, which suggests that human behavior is driven by purposeful goals and that setting specific, challenging goals improves performance [32]. For instance, when stakeholders set performance goals to reduce timber waste, they successfully reduced construction waste sent to landfills, whereas waste increased when no goals were set [33].

Furthermore, sustainability plans including sustainable purchasing policies promote the procurement of environmentally friendly products [28,34,39], enhancing waste management strategies, and can help an HEI achieve ZW goals. In 2005, the University of Southampton in the United Kingdom (UK) implemented an electronic material ordering system to centralize procurement and reduce upstream waste by prioritizing products with recycled content or which can be recycled or composted [34]. While this study highlights reduced operational and administrative costs, it does not quantify the waste reduction achieved. A qualitative study on barriers to implementing procurement programs in public universities found that decentralized procurement, where individual departments make their own purchases, complicates efforts to standardize purchasing policies [35]. Centralized procurement is thus crucial for effectively managing waste and streamlining sustainable purchasing practices. In some HEIs, sustainable purchasing is shaped by state environmental policies and ethics. For example, the University of California, Los Angeles’s sustainability plan aims to phase out single-use plastics in line with California’s ZW goals, supported by Senate Bill 54, which mandates that all packaging be reusable or compostable by 2032 [36,37]. Similarly, New York State’s Executive Order 4 requires state agencies, including HEIs, to adhere to green procurement standards, prompting the State University of New York College of Environmental Science and Forestry to implement guidelines prohibiting the purchase of items like plastic containers, straws, and water bottles [38].

Educational programs and personnel training within HEIs play pivotal roles in instilling environmental consciousness that can drive ZW initiatives. A fundamental shift in mindset—achieved through education and awareness—can help prevent and reduce waste, leading to broader personal, cultural, and societal behavioral transformations [40,83]. Studies suggest that adding environmental education to the curriculum can help provide students with intellectual tools and techniques to address environmental problems [41,46] while instilling environmental consciousness. A study at Texas A&M showed that adding a course on sustainable development to the graduate curriculum brought positive changes in student behaviors, reducing their ecological footprint from an average of 19.5 acres (7.9 ha) (measured by the amount of land needed by these students to sustain their current lifestyle on Earth) to 16.8 acres (6.8 ha), a 14% reduction, after taking the course [42]. A study conducted with 52 students from a green university observed a significant increase in sustainability knowledge following an educational intervention. The participants’ mean scores improved notably from the pre-test (mean = 3.40) to the post-test (mean = 4.08), indicating a substantial enhancement in their understanding of sustainability-related concepts. The effect size, calculated as Cohen’s d = 1, demonstrates a large impact of the intervention, highlighting its effectiveness in improving sustainability knowledge among the students [43]. Training people, especially staff, about various aspects of ZW programs, such as recycling, composting, and even sustainable purchasing, is important to raise their awareness of correct waste management practices, as well as equip them with tools to manage waste correctly, and can lead to informed decisions made by these individuals to promote sustainability in HEIs [44,53]. A study conducted by Kaplowitz et al. [45] found through a survey that staff members reported having the least knowledge about recycling (type of products that can be recycled, environmental benefits of recycling, different places on campus where products can be recycled, and types of waste reduction strategies on campus). Leal Filho et al. [46], in their review of food waste reduction in universities, emphasize the importance of training staff in food service areas to reduce food waste. These trainings can focus on key aspects such as sourcing fresh local food, adopting food preparation methods that minimize waste, and ensuring proper storage and preservation to reduce spoilage. These findings underscore the role of education in shaping waste-conscious behaviors, reinforcing that sustainability literacy is a crucial driver of ZW efforts within HEIs.

Beringer and Adomßent [84] explain that the research and development projects related to sustainability in HEIs are usually funded externally and aimed at institutional improvement for sustainability and advancing science. An example highlighting the importance of research as well as collaboration between state agencies and HEIs to reduce waste can be found in the recent selection of Iowa State University of Science and Technology by the Department of Energy to develop a closed-loop upcycling of single-use plastic films to convert them into biodegradable polymers [85]. The influence of research activity on sustainability was explored by Stafford [86], finding that more research activity by an HEI has a significant positive effect on the sustainability grade received by the HEI from the Sustainability Endowments Institute (SEI). From the perspective of IT, the SEI can be seen as a coercive force, applying external pressure on HEIs to enhance their sustainability performance. By assigning sustainability grades, the SEI establishes benchmarks and expectations that institutions must meet to maintain their reputation and competitive standing, thereby motivating HEIs to increase research efforts and adopt sustainable practices. In development projects, infrastructural changes can enhance zero-waste programs. For example, replacing multiple waste bins throughout a building with centralized waste and recycling collection units in lobbies and breakrooms [76] streamlines waste collection, making it more efficient and centralized.

Building on the importance of education and training, effective communication of waste reduction initiatives within an organization is equally vital. Semi-structured interviews with university stakeholders in the UK revealed that a lack of motivation among both the administration and students to reduce waste stems from ineffective communication regarding recycling processes and the importance of waste reduction [47]. A case study on the implementation of a ZW program at Massey University in New Zealand highlighted the significance of clear signage for recycling bins in promoting source separation behavior, which resulted in increased recycling and waste diversion, although the study did not quantify the diversion amount [48]. Additionally, an experimental study involving 20 university students in Canada found that using colored images improved the accuracy of identifying recyclables, garbage, and compostables by 6%, achieving a correct identification rate of 76%, compared to 70% with text-based messages [49].

Insufficient funding for ZW programs in HEIs can hinder program progress, often resulting in undercompensated employees and inadequate infrastructure to support effective program implementation. A semi-structured interview of 16 stakeholders (waste managers, student leaders, energy managers, and health and safety officers) from six HEIs in London revealed that, according to the participants, the biggest barrier to implementing energy-saving and waste-reduction measures in the institutions is the lack of financial resources [47]. Based on an environmental performance review of the University of Leeds, hiring more employees can result in better waste management programs [50]. The study recommends appointing an environmental officer responsible for implementing environmental activities on the campus [50]. A cost–benefit analysis of implementing an on-campus composting facility at a university in California found that it can divert 249 tons (226 tons) of food waste from a local commercial composting center and save USD 16,185 if food waste is managed at a dedicated facility, and a profit can start to be made in the ninth year [51].

Additionally, when students actively advocate for waste reduction, diversion, and other environmental initiatives at the grassroots level, they wield considerable influence in garnering support from university administrations (utilizing a bottom-up approach). For instance, Massey University’s ZW program originated in response to student concerns about the inadequacy of recycling facilities on campus [48]. Phrophayak et al. [87] attribute Mahasarakham University’s high sustainability scores to initiatives such as the creation of student clubs and associations. These groups play a key role in promoting sustainable activities on campus, including organizing recycling contests and other related projects.

The presence of a sustainability office and a dedicated committee plays a critical role in advancing sustainable practices on campus, and ZW. Filho [54] emphasizes the benefits of such offices in HEIs, noting their role in providing full-time staff, securing funding for sustainability initiatives, involving students and employees in decision-making, raising awareness, and managing sustainability data. Similarly, Levy and Marans [53] highlight that the presence of a sustainability office brings in the possibility of stakeholder collaboration by implementing environmental training in different departments, promoting sustainable purchasing, and organizing competitions among student residents, thereby enhancing student engagement and sustainability practices. Studies have also recommended the establishment of a sustainability committee, which can facilitate the task of creating and establishing campus-wide ZW and sustainability policies and targets, helping responsible authorities to implement such policies, and coordinating communication and outreach between various actors about progress on sustainability efforts [55,56,57]. Ebrahimi and North [41] further demonstrate the tangible benefits of a dedicated sustainability coordinator and committee, as seen in Western Kentucky University’s decision to hire a full-time coordinator and establish a sustainability committee. This led to immediate actions, including the allocation of USD 30,000 for recycling infrastructure allowing the continued provision of necessary infrastructural facilities for waste management. These studies collectively illustrate that by providing structure, leadership, and resources, sustainability offices and committees may serve as key drivers in advancing ZW strategies within HEIs. Without such structures, the integration of sustainable practices risks becoming fragmented and unsystematic, limiting the potential for a long-term impact.

4.2. Meso-Level Factors

Meso-level factors encompass the broader institutional and community partnerships, collaborative networks, and inter-organizational relationships that support HEIs in advancing ZW programs through shared resources, knowledge exchange, and collective action. Based on anecdotal sources, by being a part of sustainability organizations, such as AASHE, HEIs can gain cutting-edge knowledge from experts around the world on ways to reduce and prevent waste, promote sustainability on a college campus, and hence contribute to ZW [25,26]. HEIs encompass a community of scholars, students, and teachers while also being integral components of broader societal communities at the city, regional, and state levels. By sharing their expertise and resources with a wider community, HEIs can facilitate the achievement of greater sustainability outcomes by leveraging the technical knowledge and intellectual capital within HEIs. Institutional theories have suggested that an organization may also collaborate with other organizations to solve a complex or uncertain problem [88]. In the study conducted by Kezar and Bernstein-Sierra [58], an influential relationship was observed between the HEIs affiliated with the Association of American Universities and the established norms of this association concerning the enhancement of undergraduate teaching within the Science, Technology, Engineering, and Mathematics (STEM) disciplines. This influence was discerned through interconnected mechanisms, such as the desire to gain social recognition, competitions with other HEIs to improve their teachings, public acknowledgment, and the consequential opportunities for collaborative engagement with other HEIs, funding bodies, the National Research Council, and various STEM teaching associations, to advance their STEM teaching.

Studies have also emphasized the idea of HEIs advocating for sustainability, environmental policies, and climate change in communities, either by volunteering, creating community-based courses, or conducting participatory research focusing on and including local or regional communities [57,59]. HEIs can advance and advocate sustainability through the endorsement of legislation and public policies, active participation in sustainability campaigns, and involvement in decision-making with legislators [89]. According to AASHE, advocacy for sustainability includes efforts such as supporting or endorsing legislation, ordinances, and public policies that advance sustainability, participating in campaigns aiming to change public policy, and engaging in discussion with policymakers [22]. Advocating for sustainability by HEIs is considered important for several reasons. First, HEIs teach about sustainability in their courses and also seek to implement what they are teaching [60]. Second, advocating for sustainability at the local, state, or national level can be beneficial to HEIs via partnerships at local, state, and national levels. These could include partnerships with the governments providing research and development funding to HEIs to research in the field of sustainability and increase the visibility and applicability of their scientific research [90]. Additionally, NGOs can become involved with HEIs to help organize workshops and conferences on sustainability, or local communities can provide space or even research opportunities for students in HEIs to follow their academic goals [61,62]. Third, HEIs often embrace public service, and the idea of advocating for sustainability stems from the overarching objective of serving the public or the community in fostering greater sustainability [60]. By assuming this proactive role, HEIs, especially land grant HEIs that are historically meant to serve the community [62], fulfill their broader societal responsibility. The engagement of HEIs in communities beyond their academic and research roles can help bring a transformation in society and move it toward sustainability development [63].

4.3. Macro-Level Factors

Based on the literature review discussed below, macro-level factors that externally influence ZW programs in HEIs can be broadly divided into the following categories: geographic or regional effects, legal and regulatory factors, political factors affecting support of s specific policy, economic incentives, and program funding from the state or city, and technological advancement at the city, state or national level.

Various cities in the US have started adopting and integrating ZW strategies in existing waste management practices to reach sustainable development targets and promote a circular economy. In particular, ZW programs in the western US have advanced, which suggests that the region may constitute another macro-level variable that influences HEI ZW programs. Del Norte County of California prepared the first extensive ZW plan in the US in 2000 [91,92]. In 2002, San Francisco adopted a 75% waste diversion goal from landfills by 2010 and laid out a long-term ZW plan [92]. The city of Oakland passed a resolution in 2006 to adopted a strategic ZW plan [93]. Cities in other regions of the US have also adopted ZW initiatives. Austin created a ZW strategic plan in 2008 to reach the ambitious target of diverting 90% of waste from incinerators and landfills by 2040 [94]. Dallas released its ZW plan in 2013 to achieve 90% waste diversion by 2040 [95].

A previous study conducted a zonal comparison of hotels in the US on their behavior of adopting green practices using a survey (which included questions about their recycling, reuse, and waste reduction practices along with other questions on energy efficiency, education, and water conservation) [96]. They found that hotels in the Midwest adopted more green practices, followed by the West, South, and Northeast. In this study, because the hotels were divided based on zones, the zonal distribution was considered under macro-level factors as the effect of zones on the adoption of green practices depended on what state they were in and the green policies of the state, which cannot be controlled by hotels.

Regulatory and legal frameworks at the city, state, or national level play a pivotal role in shaping the effectiveness of ZW programs by enforcing measures such as mandatory recycling, source separation, and take-back policies, all of which drive waste reduction and sustainable practices in HEIs. A study performed in Asia showed that volume-based pricing or unit pricing of waste resulted in a sustained decrease in waste generation from 1.3 to 1.04 kg/capita/day in 1996 in Hong Kong and from 1.135 kg/cap/day in 1996 to 0.667 kg/cap/day in 2005 in Korea [64]. In Spain, a door-to-door waste collection system increased the source separation of waste and decreased contamination, resulting in reduced waste generation by 27% [65]. Other practices of enforcing regulations are holding producers and manufacturers liable for collecting their products back at the end of their usage, commonly known as extended producer responsibility (EPR), thus encouraging companies to manufacture innovative packaging and undertake the design of products that can last longer and be reused to reduce waste [66,67]. California passed a mandatory law to recycle in 2012 (AB 341) and compost in 2014 (AB 1826) in public and commercial facilities, including schools and HEIs that produce four cubic yards or more of commercial solid waste per week [68]. These facilities were required to provide an organic and recycling waste-collecting container next to the trash can to capture and divert recycling and organic waste [68]. The mandatory law has compelled HEIs in California to think about efforts to capture and reduce organic waste and recyclables. For example, the University of California San Diego adopted a ZW plan in 2019. In light of the ZW plan, they implemented a paper towel composting pilot program in 2022, and their waste hauler implemented an anaerobic waste digestion facility in 2021 (to digest food waste and convert it into biogas). Similarly, the University of Southern California (USC) adopted a ZW plan in 2019 to achieve ZW by 2028, and some efforts to reach ZW are being shaped by the mandatory regulations of the state [69]. In 2022, USC implemented 98 multi-stream recycling bins, which collect landfill trash, organics, mixed recyclables, and liquids separately to divert waste recyclables and compost from landfills. They have been putting on various ZW events to collect recyclables and organics during football games, tailgates, and other events on campus, diverting 18,479 pounds of waste from landfills in 2019 [69].

The effect of external stakeholders like government authorities and NGOs has been studied in the context of the adoption of environmental regulations and standards by companies, demonstrating that pressure from regulatory bodies plays a significant role in driving environmental initiatives. A quantitative study conducted on factors affecting the adoption of environmental management accounting (EMA analysis, management, and reduction in environmental costs in a mutually beneficial way for the company and the environment) by companies in Pakistan found that pressure from regulatory and authoritative bodies has the largest influence on EMA implementation in a firm [70]. Schmidt and Rocconi [71] measured the relationship between renewable energy targets of the state (targeted amount of energy that should come from renewable sources) and sustainability ratings of HEIs using a hierarchical linear model. Their results show that having renewable energy targets in the state increased the sustainability scores of HEIs. The above examples of HEIs and non-academic firms implementing ZW or sustainability programs to collect and divert recyclables and composting from landfills to conform to state laws or regulatory standards show how external pressures can shape the waste reduction and prevention efforts of an HEI.

Political factors like party affiliation, support for a policy or policy preference [97,98], expenditure on pro-environmental policies [99], and the governor’s party affiliation [99] have also been used to predict public and political support for environmental programs and policies. The political affiliation of an individual can predict their attitudes toward environmental policies. The literature shows that Democrats are more concerned about environmental and social issues than Republicans, who are mostly concerned about the economy and market [100]. Additionally, according to several studies [100,101,102], Democrats tend to allocate more funds toward environmental causes and exhibit greater concern for the environment compared to Republicans. Howe et al. [103] conducted a study on climate change opinions across different regions in the US using multilevel modeling and found that Republicans are less likely to believe in the anthropogenic effects of climate change. The literature suggests that one reason for Republicans’ reluctance to support pro-environmental policies is the perceived financial burden on capitalist firms, thus prioritizing economic gains over environmental concerns [97]. However, studies have also shown that the state’s political affiliation does not impact environmental policies. Schmidt and Rocconi [71] conducted a study using a hierarchical linear model and found that the composition of state legislatures (Republican or Democrat) did not have a significant impact on the sustainability ratings received by HEIs.

Incentives can be a motivating factor in increasing public participation in ZW programs. For instance, the city of Hernani in Spain offered a 40% discount on garbage collection fees if the residents segregated waste or composted it at home, which resulted in increased public participation in waste segregation [52]. The bottle bill incentive implemented in some states of the US, such as Oregon, Michigan, and California, has improved the collection of recyclables and reduced litter [72]. The governments of these states add a small fee (USD 0.05–0.10) during the purchase of products in plastic and glass bottles, aluminum cans, or any metal containers, which is refunded to the customers if they bring the empty containers back [73]. In Oregon, this bill resulted in a reduction in roadside litter from 40% before the bill was passed in 1971 to 6% in 1979 [72]. Incentivizing the recycling stream in such a way can reduce the quantity of waste going to landfills, increase the collection of recyclables, decrease money and time spent on collection and transport, and increase the conservation of virgin material [74]. In some cities, governmental and semi-governmental authorities may also decide to fund waste reduction programs in HEIs. For instance, the U.S. Environmental Protection Agency supports sustainability and waste reduction programs in HEIs, offering grants such as the recent USD 59,995 awarded to the University of Illinois, Chicago [75]. These incentives and funding programs, implemented at the state level, can seep into the operational mechanisms of HEIs and influence the waste reduction activities on HEI campuses. For example, the University of Oregon has various bottle redemption centers within a mile area, and it can be assumed that the students are dropping off bottles at participating grocery stores and redemption centers; in this way, they are reducing the waste on campus by diverting it. It is unknown by what percentage this reduction is occurring or if it is occurring at all, but the university is facilitating such reductions by setting up bottle collection centers in each building and collecting these bottles to generate around USD 35,000 to 45,000 annually from selling the deposited bottles and cans (Addison, D., personal communication, 10 May 2023) [104]. Even though the effect of bottle bills on recycling by students is not known, it can still be asserted that a macro-level policy such as a bottle bill has some effect on the waste reduction efforts in HEIs (micro level) as the authorities are able to collect the bottles and cans and generate income from them. The above example shows an interplay between regulatory policies at the state level, funding or incentives from the government, and waste reduction at an HEI, and that macro-level policies (state, national, international) can shape waste governance at the micro level (HEI).

Apart from incentives, investment in improved waste collection, disposal, recycling infrastructure, advanced technologies, and innovations [105,106,107] can increase a city’s waste diversion from landfills [108]. Such advancements in cities also affect the waste management of HEIs in those cities. For example, a mandatory waste separation policy in a city in China was implemented, which also focused on improving the waste-sorting infrastructure by providing separate bins for trash and recyclables and color coding the bins throughout the city, including its HEIs [77]. A survey conducted to understand the engagement and participation of students in waste separation before and after the implementation of the mandatory waste separation policy in the city found that the separation rate by college students improved from 10% to 18% after the city implemented the mandatory waste separation policy and provided the bins [77].

Technological advancements include tracking the flow of materials to landfills or other waste-processing facilities (recycling, composting, waste-to-energy). This can help understand the waste type, amount, and composition, provide improved data, and continuously monitor waste, which can improve the accountability of the cities in implementing vigilant waste management practices and policy changes [78]. Recently, companies like Rubicon have been leading the advancement in waste management by using artificial intelligence (AI) such as machine learning models to prioritize the waste collection area and time, avoid roads with parades or construction works, or even identify materials in the waste stream [79]. There are 11 cities in the US that have adopted Rubicons’ technologies to optimize their waste management. However, the effectiveness of the partnership is not yet well-documented [79]. As technology advances, such systems can also be implemented in HEIs to optimize their waste management as the waste haulers collect waste from the city and HEIs. A study in India used machine learning to simulate and enhance the segregation of electronic waste from trash by designing a mobile robot arm that identifies and segregates electronic waste and can be attached to a trash-collecting truck [80]. The arm exhibited 96% accuracy in identifying and segregating electronic waste. The study proposes that using a similar machine learning concept can improve the collection and segregation of hazardous electronic waste with minimum harm to humans. As can be seen from the above studies, the application and acceptance of AI and machine learning in the field of waste management are very recent and mostly directed toward cities; however, these practices, such as using AI to segregate waste and investing in waste management infrastructure, have the potential be applied to HEIs as well.

In this study, being a public or private HEI (institutional control) and being a doctoral, master, baccalaureate, or associate HEI (institutional type) is not divided into micro, meso, or macro factors because the governance of the HEI can be subject to the discretion of the board of trustees, state government, accreditation agencies, and establishing stakeholders. Usually, public HEIs are funded by the state [78] and have some state governmental control [109]. Private HEIs usually govern themselves and hence have more autonomy over their governance [109], but sometimes private HEIs also receive funding from the state or federal government. Therefore, the institution’s governance can be characterized as discretionary, and the investment of funds can depend on the source of funding. Studies have explored the relationship between institutional type and control and sustainability efforts. Studies using Sustainability Tracking Assessment and Rating Systems’ data have shown that doctoral-level [71,110] and public HEIs [69] have the highest overall sustainability scores. This may be because Carnegie doctoral research HEIs usually gain higher funding for research and foundation grants from private donors and public funding agencies as they are viewed as elite research institutions compared to master-, baccalaureate-, and associate-granting institutions [111]. Therefore, they may have higher scores on sustainability as there are greater chances for them to invest in sustainability efforts. A reason why public HEIs may achieve higher sustainability scores than private HEIs is that public HEIs are funded through the state by means of grants or sponsored research funds usually paid through state taxes, and hence, they are subject to public or state pressure to implement sustainable management practices [112]. On the other hand, private HEIs may have less external stakeholder pressure as they rely on grants, endowments, tuition, and philanthropic donations [112,113]. In summary, for a study of national or international waste diversion and minimization, where the unit of analysis is not HEIs but states or nations, the institutional type and control could be considered a micro-level category, which will mean that states or nations with a higher number of public HEIs have higher diversion compared to private HEIs based on the above discussion. But at the institutional level, such as in this study, these factors do not clearly fall under the micro-, meso-, or macro-level category and, therefore, are kept in the “other” factors category.

5. Discussion

There are some indicators found through the literature review above that can be clearly explained by IT. For instance, the effect of a full-time employee on ZW programs can be explained by the concept of normative isomorphism, wherein professionals who share a common educational background and hold comparable positions in diverse organizations tend to exhibit similar behaviors. This similarity in behavior often results in the adoption of practices that are considered standard and widely accepted as effective in their professional field. Therefore, due to normative isomorphism, having full-time employees can result in better ZW programs.

The impact of education and training can significantly increase the likelihood that staff and students will comply with acceptable waste reduction and prevention practices. This improvement can be attributed to normative isomorphism, where, after acquiring knowledge, staff members gain a better understanding of the importance of waste reduction and are motivated to adopt similar sustainable practices. Additionally, coercive pressures from the administration to implement training programs and educational resources, as well as from SEI, which encourage institutions to improve their performance for better benchmarking and reputation, also play a role. These pressures drive institutions to actively pursue and achieve their sustainability goals.

It also comes to light that HEIs conducting research activities are more likely to have better sustainability programs since they are more likely to secure external research funds [84,85]. Due to normative isomorphism, HEIs might want to become involved in sustainability-related research since conducting research is one of the various purposes of an HEI. Normative isomorphism drives HEIs to participate in sustainability-related research, as conducting research is a core mission of these institutions. This creates a mutualistic relationship where HEIs actively pursue sustainability research to attract funding, which in turn benefits the funders through impactful research outcomes. Hence, the pursuit of and investment in sustainability research by HEIs, encompassing ZW paradigms, can yield enhanced ZW programs.

The role of students and student organizations in advocating for zero-waste programs highlights the presence of normative isomorphism within HEIs. As HEIs educate their students about sustainability, these students become empowered advocates for the practical implementation of zero-waste principles. Consequently, HEIs feel a responsibility to respond to and support these advocacy efforts.

It can also be inferred from the results that a sustainability office serves as a central hub for all sustainability-related activities on campus, facilitating effective communication among stakeholders, supporting funding availability, and facilitating the employment of dedicated staff for sustainability projects. It creates an enabling environment for the implementation of sustainability initiatives, fostering widespread engagement and acceptance within the campus community. This stakeholder participation is driven by normative isomorphism, as individuals feel obligated to join sustainability committees due to their professional interests. Moreover, HEIs respond to stakeholder expectations through normative isomorphism by seeking support and validation while addressing their demands. After establishing a sustainability office and committees, these entities may also feel compelled to adopt widely accepted practices in their field, such as hiring sustainability officers and promoting funding for sustainability projects. This assumption is also supported by a qualitative study involving interviews with seven sustainability leaders from construction companies based in the UK, which revealed a significant driver for construction companies to embrace sustainability is their pursuit of winning more contracts, stemming from a combination of factors, including client demands for sustainable practices and social recognition [114]. The study highlights the effect of normative isomorphism, where construction firms, in their quest for social recognition and a competitive edge, gravitate toward adopting sustainable practices. Additionally, the presence of a sustainability office may be influenced by mimetic isomorphism, as HEIs might imitate successful practices from other institutions. Thus, the establishment and impact of a sustainability office and committee can be shaped by both normative and mimetic isomorphism.

HEIs engage in sustainability networks through the lenses of mimetic and normative isomorphism [57,58]. Mimetic isomorphism explains this involvement as HEIs seek to access shared resources to enhance their sustainability efforts by learning from the best practices of their peers. Normative isomorphism further influences this behavior, as HEIs feel it is the norm to engage in and advocate for sustainability through such platforms, aiming to be seen as legitimate among their peers. An important aspect to consider is that strong advocacy from HEIs may also lead to significant changes in local government policies, which in turn shape the sustainability landscape within these institutions. This influence can manifest as coercive isomorphism, compelling HEIs to comply with newly established sustainability standards and regulations. Thus, sustainability advocacy within HEIs is a complex process that involves elements of mimetic and normative isomorphism, potentially giving rise to coercive, normative, and mimetic isomorphism. This interplay ultimately drives systemic changes in the higher education sector.

At last, the regulatory policies pertaining to the types of waste reduction programs and amounts of investment in such programs at city, state, or national levels are informed by coercive isomorphism. For instance, if a city or state implements advanced technology and policies to enhance waste reduction, these developments will ultimately influence how HEIs manage their waste. HEIs may experience both coercive and normative isomorphism when government agencies or NGOs provide funding for waste management projects. To secure such funding, HEIs may be motivated to conduct research and advance ZW programs within their institutions. Additionally, engaging in these initiatives can enhance their public image and improve their rankings.

To summarize, the findings and discussion suggest that macro-level factors predominantly influence ZW programs through coercive isomorphism. This reflects macro-level forces such as market prices or state regulatory policies. In contrast, at the meso and micro levels, there is a complex interplay of normative and mimetic influences. In the context of research on collaboration occurring at the meso level, significant emphasis is placed on organizations collaborating to acquire distinctive resources or skills that are challenging for other entities to imitate. This underscores the impact of norms and mimesis in advancing sustainability within the broader community, stemming from collaborative efforts to attain social recognition and access to shared resources.

Table 3. Factors based on literature review divided by scale (micro, meso, and macro) and type of isomorphism.

Type of Isomorphism	Micro	Meso	Macro
Coercive	Sustainable purchasing policies in HEIs influenced by state laws; mandated education and training of staff and students.		Volume-based pricing; mandatory extended producer responsibility; door-to-door waste collection; expenditure on pro-environmental policies and the governor’s party affiliation; bottle bill incentive; government investing in waste reduction programs at HEIs; implementing waste-sorting infrastructure and mandatory waste segregation; tracking material flow to landfills.
Normative	Promoting sustainable practices inside the organization due to social recognition; presence of sustainability officer, sustainability office, full-time employees in a sustainability department, and sustainability committee; presence of student organizations and their efforts; environmental education; sustainability training; research on sustainability-related projects.	Advocating for sustainability at city, state, national, or international level; participation in sustainability networks.
Mimetic	Creation of sustainability office; hiring a sustainability officer (mimicking other successful programs).	Participation in sustainability networks.

summarizes the explanatory factors for ZW programs, organized based on the level of scale (micro, meso, and macro) and type of isomorphism (coercive, mimetic, and normative), and aims to shows how specific factors at different scales reflect different and convoluted forms of isomorphism.

6. Recommendations and Conclusions

This study aimed to address the growing challenge of implementing ZW programs, particularly in the context of higher education institutions (HEIs), using the concept of systems hierarchy. Despite the global emphasis on sustainable development, particularly through initiatives like SDG 12, a significant gap exists in understanding how HEIs can effectively implement ZW frameworks and track their progress. So, this study sought to conceptualize a comprehensive framework that integrates various dimensions in which an HEI interacts and supports the classification of the ZW indicators accordingly.

There are large variables that interplay at the micro level in an HEI, but the effectiveness of ZW programs is higher when these institutions receive external, often authoritative command, such as mandatory laws to divert waste. The HEIs do not interact much at the meso level, and if they do, it is solely for advocating for their needs or fulfilling criteria to meet the requirements of reporting institutes for a better sustainability score and reputation. So, future studies should explore the interaction at the meso level in more depth. One thing is very clear: there is an interplay between normative, mimetic, and coercive isomorphism, which together shape the effectiveness of ZW programs. The findings emphasize the complex and multifaceted nature of policy adoption in an institution, underscoring the importance of both internal organizational factors and external regulatory influences on institutional behavior. The review of the literature and findings also suggest that future research should prioritize research and case studies on ZW programs and their progress in HEIs to enrich the existing body of literature and practical knowledge about successful ZW programs in HEIs. Since this study is a broad review aimed at advancing the field of ZW in HEIs, our findings provide a foundation for future research rather than definitive conclusions. While we sought to capture diverse perspectives, the applicability of our results may vary across different types of HEIs and geographic contexts. This highlights the need for more localized studies and case-specific analyses to further refine and strengthen ZW strategies in higher education.

Additionally, the review highlights several key recommendations for HEIs, including developing a ZW plan with clear targets and goals for waste reduction and diversion, investing in education and training programs focused on ZW practices, enhancing infrastructure to support ZW efforts, hiring dedicated staff to oversee and implement ZW initiatives, and engaging in professional sustainability and ZW networks to stay informed about the latest developments in the field. For policymakers, a key recommendation from the review is to implement and support coercive measures, such as mandatory recycling and composting laws, as well as other waste reduction initiatives like bottle bills and extended producer responsibility laws. For other stakeholders, such as cities and communities, it is crucial to invest in waste sorting and recycling infrastructure to efficiently recover recyclables, track material flow to landfills to analyze trends, and enact policies accordingly.