Content uploaded by Christian Wankmüller
Author content
All content in this area was uploaded by Christian Wankmüller on Oct 07, 2021
Content may be subject to copyright.
1
The impact of blockchain-enabled tokenization on
plastic waste: an empirical study
Johannes Pulsfort (johannes.pulsfort@wu.ac.at)
Institute for Transport and Logistics Management, Vienna University of Economics and
Business, Vienna, Austria
Christian Wankmüller (christian.wankmueller@aau.at)
Institute for Production-, Energy- and Environmental Management, University of
Klagenfurt, Klagenfurt, Austria
Gerald Reiner (gerald.reiner@wu.ac.at)
Institute for Production Management, Vienna University of Economics and Business,
Vienna, Austria
Abstract:
This paper describes the first steps in the course of a pilot recycling initiative with the
aim of investigating blockchain-enabled tokenization as an alternative incentive system
to increase recycling rates of plastic bottles to enable the shift to circular plastic supply
chains. As little knowledge exists regarding the effects of novel technology
implementation on plastic bottle recycling rates, we conducted exploratory research,
using expert interviews and focus group discussions with representatives from an
international beverage company. This served for obtaining preliminary insights into the
potential application of novel technologies (e.g. blockchain) in terms of tokenization in
combination with incentive schemes within the plastic bottle supply chain, especially
about the end-consumer collection and recycling rate behaviour.
Keywords (3 keywords): plastic waste, circular economy, blockchain technology
Introduction
Today’s polyethylene terephthalate (PET) plastic bottle supply chain (SC) is complex and
imposes challenges across the globe (Ragaert et al. 2017). Plastic bottle recycling rates in
the European Union (EU) average 58.2% in 2018 according to statistics (Eurostat 2020).
Although the trend is towards decreasing amounts of plastic waste due to recycling
efforts, the topic further needs to be investigated as the plastics produced in Europe
amounted to 61.8 million tons in 2018 and thereof, 39.9% refer to plastic packaging
(Statista 2020). According to official numbers, the amount of plastic packaging waste
within the EU amounted to 3.3 million tons in 2018 (Statista 2020). Apparently, the clear
need is given to identify and implement adequate countermeasures, as existing strategies
for reducing plastic pollution seem to fail in reality. Among recent technological
2
innovations to facilitate recycling efforts, blockchain technology (BT) may offer the
required features for addressing certain causes of plastic pollution.
BT is a distributed ledger technology (DLT), which records transactions in a
decentralized manner by creating secure recordings also referred to as blocks (Nakamoto
2008). Satoshi Nakamoto first proposed the concept of BT in his white paper where
Bitcoin, the first application of BT, was described. BT combines relevant features such
as reliability, traceability, data immutability and smart contracts that can enable a trustless
environment where no intermediary is needed (Iansiti and Lakhani 2017). According to
scholars, one of the main advantages of BT is to enhance sustainability of SCs (Saberi et
al. 2019). BT can help to enhance plastic bottle traceability, visibility and quality in the
logistics process by assigning a unique identity to individual bottles (Saberi et al. 2019).
BT can provide the technical infrastructure where several and distinct stakeholders can
access the same information at the same time (Helo and Hao 2019).
One of the most promising concepts facilitated by BT is tokenization. Tokenization,
when applied to BT indicates representing the value of a physical asset in a unique digital
data format based on blockchain data structure. A token is a value container including
various data points that represent assets, utility or claims within a blockchain environment
(L. Oliveira et al. 2018). The tokenization of single plastic bottles can create visibility
through digitization and each partner of the plastic bottle SC can validate the data
transactions in form of a participating node (Bekrar et al. 2021). Tokenization in
combination with existing traceability systems can create a more agile value chain and
enable a closer end-consumer relationship (Nandi et al. 2021). BT and tokenization
represent novel ideas on how to potentially increase recycling rates through incentivizing
end-consumers when returning plastic bottles appropriately (Babich and Hilary 2019). In
order to increase recycling rates, this research paper discusses how recycling rates can be
increased through BT and tokenization where end-consumers are incentivized for
accurate return of plastic bottles and possibly lead to a circular economy (CE) for the
plastic SC. Furthermore, BT and tokenization can contribute towards Sustainable
Development Goals (SDGs) of the United Nations (United Nations 2015). In order to
investigate the impact of tokenization on recycling rates, the following research question
(RQ) was formulated:
RQ: How may blockchain-enabled tokenization contribute to improved recycling rates of
plastic bottles?
The objective of this study is to learn more about the potentials of tokenization to
improve recycling rates of plastic bottle waste in SCs. Therefore, we turn to practice and
grasp managers’ point of views on the subject by conducting expert interviews and group
discussions with several key stakeholders. Consequently, this paper aims to reveal
preliminary empirical research to complement already existing conceptual and theoretical
knowledge of BT and tokenization in the context of circular plastic SC (Kouhizadeh et
al. 2020).
This paper is outlined as follows. First, BT and tokenization in the context of recycling
rates in the plastic SCs are introduced in the related work section. Second, the selected
methodology is explained. Third, the findings section comprehensively outlines trade-
offs challenges and opportunities of applying BT and tokenization to enable the circular
plastic value SC, followed by the discussion section. Finally, research implications are
presented, limitations are illustrated and the conclusion is presented.
Related work
3
Plastic resembles a global and widely acknowledged problem for humanity next to carbon
emissions (Sudesh and Iwata 2008). “Plastics are inexpensive, lightweight and durable
materials, which can readily be molded into a variety of products that find use in a wide
range of applications” (Hopewell et al. 2009). Nonetheless, society didn’t succeed
overseeing the entire life-cycle of plastics (Thompson et al. 2009). In order to promote
reusing and recycling, it is essential to comprehend and solve the current problems in the
system that facilitate plastic waste removal (Hahladakis and Iacovidou 2019). The main
holdup is owed to absence of consistent information about the accessibility, magnitude,
value, and aptness of recycled plastic feedstock (Hopewell et al. 2009). Without such
reliable information, manufacturers are not motivated to procure recycled feedstock
instead of virgin polymers (Al-Salem et al. 2009). As a result, in 30 years, oceans will
contain more plastic by volume than fish (Lebreton et al. 2018). According to Ritchie and
Roser (2018), in 2015 worldwide, 50% to 60% of the overall plastic waste was dumped
in landfills and oceans, 20% to 30% was incinerated, and 10% to 20% was reprocessed
and recycled (European Environment Agency 2021).
Waste management policies are developing towards less linear and more sustainable
approaches, which means that recovery of resources from waste is gaining more and more
importance (Iacovidou et al. 2017). With regard to sustainability, the concept of the CE
is crucial to be considered (Korhonen et al. 2018). Furthermore, CE is quite popular but
still requires further academic efforts (Kirchherr et al. 2017). Commonly, CE denotes “an
economic model aimed at the efficient use of resources through waste minimization, long-
term value retention, reduction of primary resources, and closed loops of products,
product parts, and materials within the boundaries of environmental protection and socio-
economic benefits” (Morseletto 2020).
Scholars of recent years found that if the recycling process allows one to receive high
quality material, then not only environmental benefits from the recycling process, but also
financial revenues are possible (Faraca et al. 2019). Consequently, less raw material
inputs are used and occurrence of plastic waste is reduced when the appropriate
managerial implications are implemented (Nakamura and Kondo 2002). A model by Dace
et al. (2014) for analyzing effects of eco-design policy on packaging waste management
systems shows that higher price elasticity of demand for materials, fosters a decrease of
materials used and the total consumption of packaging materials.
This will improve awareness of using plastics on the one hand, but also the awareness
of plastic waste and may increase the recycling rate on the other hand (Panda et al. 2010).
Therefore, plastic waste can be seen as a commodity since the material value can
contribute to the economic benefit of a company (Ranta et al. 2018). Moreover, a better
understanding of the plastic life cycle should be gained (Finnveden et al. 2009).
Especially in the case of plastic waste, closing the life cycle is essential to save input
materials, to become resource efficient and to mitigate the amounts of plastic waste (Gu
et al. 2017). At this point it has to be noted, that preserving resources is crucial to be
supported by policies (Iacovidou et al. 2017). In addition, decision making should be
based on facts (Iacovidou et al. 2017). Another aspect that scholars emphasize is that
peoples’ consumption and disposal patterns are not well understood and may cause
ineffective measure implementation by responsible decision-makers (Iacovidou et al.
2017). Apparently, BT represents an approach to potentially facilitate CE in the context
of plastic bottle waste due to the following characteristics (Saberi et al. 2019). First, BT
creates SC visibility for all participating partners in the network (Kouhizadeh and Sarkis
2018). Second, BT allows for tokenization of single plastic bottles and offers the
opportunity to incentivize the end-customer (Liu et al. 2021). Third, BT and tokenization
induce flexible incentives that can result in more socially and environmental donations
4
(Kouhizadeh and Sarkis 2018). Fourth, using BT for external data audits on plastic bottle
recycling prevents from green washing (Forrest et al. 2019). Finally, BT provides data
integrity to all participating private blockchain consortium members (Hasselgren et al.
2020). The blockchain platform serves as a trust-based network that represents the
backbone to share and validate information between various parties (Hawlitschek et al.
2018).
Methodology, data gathering and analysis
This study represents the first step in the course of a recycling initiative with the aim of
testing blockchain-enabled tokenization, as an alternative incentive system to traditional
deposit-refund systems, to increase recycling rates of plastic bottles. As little knowledge
exists regarding the effects of novel technology implementation on plastic bottle
recycling rates, we conducted qualitative research, using expert interviews and focus
group discussions with representatives from an international beverage company that
focuses on technology and sustainability. The selected company for this study
encompasses various focal points for the investigation of plastic bottle recycling rates and
the interest in the use of digital technologies including BT. In detail, we interviewed three
experts and held five focus group discussions with the global corporate affairs and
communication director, global SC director, and group SC planning director of an
international beverage company with more than 10.000 employees worldwide. All of the
participants have more than 20 years of professional experience in the sectors. The main
expert statements of each interview have been summarized. Therein, we were primarily
interested in the individual experts’ thoughts and opinions on the potentials of blockchain-
enabled tokenization to increase recycling rates. This served for the collection of
empirical data that will be further subject of quantitative modeling to analyze the value
generated by BT for improving plastic bottle collection rate in a next step.
Findings
Empirical research findings
Expert interviews brought to the light first impressions on how tokenization and BT could
enable disruptive changes towards more effective and efficient management of plastic
bottle waste. As the global public affairs director stated about the potential of
tokenization: “We believe that the value proposition of tokenization can contribute to
sustainability. Proper implementation of tokenization can reduce plastic pollution and
minimize waste. Plastic bottle waste becomes material where ownership can be assigned
and that material ownership provides transparency and accountability. Furthermore,
tokenization of plastic bottle waste can be perceived as an alternative to the current
deposit-refund systems. Tokenization of plastic bottle waste creates a digitized SC
platform where several stakeholders as the government and other participants can be on-
boarded. Citizens and end-consumers can obtain a personal plastic balance sheet and
monitor their contribution to sustainability by collecting tokens through the proper return
of plastic bottles. Recycled plastic bottles can potentially lower the need for using virgin
material and thus preventing further waste in the future.”
The expert statement reveals interesting insights with regard to the evident strengths
of tokenization. Other top managers of international companies can potentially relate to
the key points raised about tokenization. The managerial implications of providing an
application to better trace plastics and to assign plastic items to end-consumers in order
to enhance their sense of responsibility but also to better understand the life cycle of
plastics. As this exploratory study allows one to analyze various factors for strengthening
5
the understanding of complexity, there is a wide-range of further aspects to investigate in
that field.
Another relevant insight from an expert interview with the global SC manager of a
beverage company is the following: “BT provides the possibility to track and trace single
plastic bottles. Through tokenization, plastic bottles can obtain a “digital material
passport” encompassing all the necessary information such as the history of the product,
composition, ownership and status. Through enhanced data quality and the possibility of
track and trace on item level, auditors and the government can check recycling rate and
companies can prove through blockchain-enabled tokens that regulations were abided
by, avoiding penalties related to the plastic tax.”
This empirical observation substantiates the theoretical knowledge and allows for
more detailed insights on the potential impact of tokenization. Environmental auditors
can benefit from enhanced data quality due to BT and tokenization. Via tokenization, BT
possibly generates incentives that contain financial (i.e., cryptocurrencies like Bitcoin) or
non-financial tokens (Chen 2018) for supporting organizational missions, i.e. plastic
bottle recycling, including CE and SC practices (Kouhizadeh et al. 2020). Firms are
adopting BT to address various sustainable SC issues, such as food contamination, carbon
credits, and plastic bottle waste, by the creation of decentralized, immutable and reliable
data, transparency, traceability, smart contracts, and incentivization (Groening et al.
2018). Additionally, BT provides multi-tier SC insights starting at input suppliers to end-
user consumers and plausible circular SC linkages (Kouhizadeh and Sarkis 2018; Saberi
et al. 2019).
Additional first-hand insights were provided by the global SC planning manager from
a beverage company stating that: “Another interesting aspect of using BT and
tokenization for increasing the collection rate of plastic bottles is the possibility of
gamification. Creating a new fashion trend to collect plastic bottles can be enabled
through the usage of blockchain-enabled token enhancing overall sustainability.
Additionally, BT and tokenization allow for a scalable solution to serialize all the plastic
bottles produced which improves SC efficiency.”
These empirical findings show preliminary insights of possible additional dimensions
to the tokenization of individual PET bottles. First, the development of plastic waste
amounts, based on PET plastic bottles for end-consumers and computation of the
potential of plastic waste reduction (Finnveden et al. 2013). Second, using BT to support
tracking and tracing of individual bottles allows a better understanding of the life cycle
of plastics (Provencher et al. 2014). Third, the consumer aspects include the motivation
for recycling (due to the mobile application, changes in demand, tokenization and
incentives, gamification etc.) (Aguiar Castillo et al. 2018). Fourth, consideration of
additional synergies for sustainable development to obtain higher collection rates. Higher
recycling rates increase visibility of the plastic work in process (U. R. de Oliveira et al.
2018). Empirical findings can also contribute towards SDGs of the United Nations
(United Nations 2015). For example, to ensure sustainable consumption and production
patterns by saving raw material when increasing recycling rates. Another aspect is how
to sustainably use the oceans, seas and maritime resources for sustainable development
by reducing plastic waste. SDG 12.5 explicitly states that “by 2030, we need to
substantially reduce waste generation through prevention, reduction, recycling and reuse”
(United Nations 2015).
6
Discussion
First and foremost, BT allows achieving plastic flow transparency along the different
stages of a SC, from manufacturer, to beverage, retailer and end-consumer. Additionally,
SC data may help to improve handling and processing among the different stages and to
gather better data of the usage phase of PET bottles. BT facilitates the secure exchange
of data due to cryptography and decentralized information processing. BT provides the
same information for all participating stakeholders breaking up traditional data silo
architectures. BT and tokenization can facilitate the CE of the plastic bottle SC by
digitizing the processes and providing the digital infrastructure to participating
stakeholders. BT may facilitate the entire industry to combat plastic pollution by
providing transparency and openness. In order to unlock this value, BT expedites the
waste collection and management process and may facilitate the tokenization of the
plastic bottle waste through disintermediation.
As stated previously, the concept of CE is critical to be taken into consideration
(Corona et al. 2019). Actually, the idea of the CE is experiencing increased interest by
both, research and practice (Kirchherr et al. 2017). As the concept of CE requires “a
fundamental systemic change instead of a bit of twisting of the status quo to ensure its
impact” (Kirchherr et al. 2017), intensified research is still required. BT provides the
technical framework that can possibly facilitate the circular plastic SC through
transparent data that is immutable and provides trust for participating stakeholders (Nandi
et al. 2021). However, blockchain-based tokens pose several advantages. First, tokenizing
physical plastic bottles into tokens converts plastic waste into an asset. Second, tokens
can be used for accountability and transparency proofing sustainable behaviour (Leng et
al. 2020). Third, token redemption allows for possible donations to social or
environmental causes by end-consumers potentially accelerating additional sustainable
initiatives. Fourth, tokens can be used in other blockchain-based systems potentially
paving the way towards token economy (Lee 2019).
This constitutes preliminary work in the course of joint initiative that will form the
basis of future empirical research. It is crucial to investigate the impact on the plastic
recycling rate by using BT and tokenization, which can provide an end-consumer PET
balance data sheet, to better track and trace PET bottles in order to reduce plastics waste
in the end and to contribute a development towards circularity in the plastic bottle SC
(Kouhizadeh et al. 2020). BT and tokenization of plastic bottles can initiate the token
economy where other materials of interest can become tokenized in the future (Morrow
and Zarrebini 2019).
Research implications, limitations and conclusion
The developed paper presents first insights from expert interviews that highlight the
potential that BT and tokenization can have on recycling rates. This innovative approach
allows evaluating the impact of incentives on the increase of collection rates. This might
be an enabler to increase recycling rates, thereby realizing circular plastic SC. A
sustainable plastic inventory management combined with the traceability system and
innovative SC policies can create, e.g., a more risk hedging plastic value chain in terms
of virgin raw material prices, etc. (Matar et al. 2014; Reiner et al. 2014) that will increase
SC efficiency as well.
The major contribution is to show the interest the perceived impact of blockchain
adaption might have for the case of tracking and tracing PET-bottles to achieve potentially
higher collection rates. This allows to save virgin material and to move towards circularity
in the usage of plastic bottles. With regard to the consumers, the application of that
tracking and tracing-based recycling system provides users with transparency about their
7
plastics consumption, thereby fostering the consumers’ sense of responsibility. The
gathered information may also facilitate improved processes within the SC and to better
plan process alternatives, as more detailed data can be used for analyzing the plastic
bottles life cycle.
This study has several limitations. We are aware of the fact that the inclusion of
beverage company experts may influence the results. Perspectives on the subject from
other SC partners should therefore be collected in future research. In addition, the study
area should not be limited to one specific geographic region only; hence replicating the
same interviews and group discussions is advised in future. We know that the first insights
generated by this study are not fully generalizable, and solely provide a rough direction,
as the entire research concerning recycling rates is more complex. It is to be noted that
future research can also be applied to other SCs such as the food SC. Of course, circular
SCs deserve intensified academic attention, nevertheless this study is valuable as it is the
first showing that BT and tokenization offer potentials to increase recycling rates. In
subsequent research, further expert interviews and focus group discussion are needed to
validate possible potentials of BT and tokenization.
Another part of future research will be the investigation of a mobile phone application
that enables an end-consumer to scan a quick response (QR) code printed on a single
plastic bottle and returning it to a smart bin that also possesses a QR code that can be
scanned by the end-consumer. After successfully scanning and returning the plastic
bottle, the end-consumer obtains tokens that can be redeemed for a variety of benefits,
potentially incentivizing and increasing the overall PET bottle-recycling rate.
Additionally, BT allows for reward tokens for end-consumers that may generate a sense
of responsibility and an incentive to return the plastic bottle back into the circular plastic
SC.
Acknowledgement
We wish to acknowledge the Austrian Blockchain Center (ABC) Research GmbH for
supporting our research on Blockchain Technology and Sustainability.
References
Aguiar Castillo, L., Rufo Torres, J., De Saa Pérez, P., and Pérez Jiménez, R. 2018. “How to Encourage
Recycling Behaviour? The Case of WasteApp: A Gamified Mobile Application.” Sustainability [ISSN
2071-1050], v. 10 (5), Article Number 1544. https://accedacris.ulpgc.es/jspui/handle/10553/41517.
Al-Salem, S. M., Lettieri, P., and Baeyens, J. 2009. “Recycling and Recovery Routes of Plastic Solid Waste
(PSW): A Review.” Waste Management 29 (10): 2625–2643.
Babich, V., and Hilary, G. 2019. “OM Forum—Distributed Ledgers and Operations: What Operations
Management Researchers Should Know About Blockchain Technology.” Manufacturing & Service
Operations Management 22 (2): 223–240.
Bekrar, A., Ait El Cadi, A., Todosijevic, R., and Sarkis, J. 2021. “Digitalizing the Closing-of-the-Loop for
Supply Chains: A Transportation and Blockchain Perspective.” Sustainability 13 (5): 2895.
Chen, Y. 2018. “Blockchain Tokens and the Potential Democratization of Entrepreneurship and
Innovation.” Business Horizons 61 (4): 567–575.
Corona, B., Shen, L., Reike, D., Rosales Carreón, J., and Worrell, E. 2019. “Towards Sustainable
Development through the Circular Economy—A Review and Critical Assessment on Current
Circularity Metrics.” Resources, Conservation and Recycling 151 (December): 104498.
Dace, E., Bazbauers, G., Berzina, A., and Davidsen, P. I. 2014. “System Dynamics Model for Analyzing
Effects of Eco-Design Policy on Packaging Waste Management System.” Resources, Conservation and
Recycling 87 (June): 175–190.
European Environment Agency. 2021. “The Plastic Waste Trade in the Circular Economy.” Briefing.
https://www.eea.europa.eu/publications/the-plastic-waste-trade-in.
8
Eurostat. 2020. “Recycling Rate of Packaging Waste by Type of Packaging - Products Datasets -.”
https://ec.europa.eu/eurostat/web/products-datasets/-/cei_wm020.
Faraca, G., Martinez-Sanchez, V., and Astrup, T. F. 2019. “Environmental Life Cycle Cost Assessment:
Recycling of Hard Plastic Waste Collected at Danish Recycling Centres.” Resources, Conservation and
Recycling 143 (April): 299–309.
Finnveden, G., Ekvall, T., Arushanyan, Y., Bisaillon, M., Henriksson, G., Gunnarsson Östling, U.,
Söderman, M. L., et al. 2013. “Policy Instruments towards a Sustainable Waste Management.”
Sustainability 5 (3): 841–881.
Finnveden, G., Hauschild, M. Z., Ekvall, T., Guinée, J., Heijungs, R., Hellweg, S., Koehler, A., Pennington,
D., and Suh, S. 2009. “Recent Developments in Life Cycle Assessment.” Journal of Environmental
Management 91 (1): 1–21.
Forrest, A., Giacovazzi, L., Dunlop, S., Reisser, J., Tickler, D., Jamieson, A., and Meeuwig, J. J. 2019.
“Eliminating Plastic Pollution: How a Voluntary Contribution From Industry Will Drive the Circular
Plastics Economy.” Frontiers in Marine Science 6.
https://www.frontiersin.org/articles/10.3389/fmars.2019.00627/full.
Groening, C., Sarkis, J., and Zhu, Q. 2018. “Green Marketing Consumer-Level Theory Review: A
Compendium of Applied Theories and Further Research Directions.” Journal of Cleaner Production
172 (January): 1848–1866.
Gu, F., Guo, J., Zhang, W., Summers, P. A., and Hall, P. 2017. “From Waste Plastics to Industrial Raw
Materials: A Life Cycle Assessment of Mechanical Plastic Recycling Practice Based on a Real-World
Case Study.” Science of The Total Environment 601–602 (December): 1192–1207.
Hahladakis, J. N., and Iacovidou, E. 2019. “An Overview of the Challenges and Trade-Offs in Closing the
Loop of Post-Consumer Plastic Waste (PCPW): Focus on Recycling.” Journal of Hazardous Materials
380 (December): 120887.
Hasselgren, A., Kralevska, K., Gligoroski, D., Pedersen, S. A., and Faxvaag, A. 2020. “Blockchain in
Healthcare and Health Sciences—A Scoping Review.” International Journal of Medical Informatics
134 (February): 104040.
Hawlitschek, F., Notheisen, B., and Teubner, T. 2018. “The Limits of Trust-Free Systems: A Literature
Review on Blockchain Technology and Trust in the Sharing Economy.” Electronic Commerce Research
and Applications 29 (May): 50–63.
Helo, P., and Hao, Y. 2019. “Blockchains in Operations and Supply Chains: A Model and Reference
Implementation.” Computers & Industrial Engineering 136 (October): 242–251.
Hopewell, J., Dvorak, R., and Kosior, E. 2009. “Plastics Recycling: Challenges and Opportunities.”
Philosophical Transactions of the Royal Society B: Biological Sciences 364 (1526): 2115–2126.
Iacovidou, E., Millward-Hopkins, J., Busch, J., Purnell, P., Velis, C. A., Hahladakis, J. N., Zwirner, O., and
Brown, A. 2017. “A Pathway to Circular Economy: Developing a Conceptual Framework for Complex
Value Assessment of Resources Recovered from Waste.” Journal of Cleaner Production 168
(December): 1279–1288.
Iansiti, M., and Lakhani, K. R. 2017. “The Truth About Blockchain.” Harvard Business Review, January
1. https://hbr.org/2017/01/the-truth-about-blockchain.
Kirchherr, J., Reike, D., and Hekkert, M. 2017. “Conceptualizing the Circular Economy: An Analysis of
114 Definitions.” Resources, Conservation and Recycling 127 (December): 221–232.
Korhonen, J., Honkasalo, A., and Seppälä, J. 2018. “Circular Economy: The Concept and Its Limitations.”
Ecological Economics 143 (January): 37–46.
Kouhizadeh, M., and Sarkis, J. 2018. “Blockchain Practices, Potentials, and Perspectives in Greening
Supply Chains.” Sustainability 10 (10): 3652.
Kouhizadeh, M., Zhu, Q., and Sarkis, J. 2020. “Blockchain and the Circular Economy: Potential Tensions
and Critical Reflections from Practice.” Production Planning & Control 31 (11–12): 950–966.
Lebreton, L., Slat, B., Ferrari, F., Sainte-Rose, B., Aitken, J., Marthouse, R., Hajbane, S., et al. 2018.
“Evidence That the Great Pacific Garbage Patch Is Rapidly Accumulating Plastic.” Scientific Reports 8
(1): 4666.
Lee, J. Y. 2019. “A Decentralized Token Economy: How Blockchain and Cryptocurrency Can
Revolutionize Business.” Business Horizons, Digital Transformation & Disruption, 62 (6): 773–784.
Leng, J., Ruan, G., Jiang, P., Xu, K., Liu, Q., Zhou, X., and Liu, C. 2020. “Blockchain-Empowered
Sustainable Manufacturing and Product Lifecycle Management in Industry 4.0: A Survey.” Renewable
and Sustainable Energy Reviews 132 (October): 110112.
Liu, C., Zhang, X., and Medda, F. 2021. “Plastic Credit: A Consortium Blockchain-Based Plastic
Recyclability System.” Waste Management 121 (February): 42–51.
Matar, N., Y. Jaber, M., and Searcy, C. 2014. “A Reverse Logistics Inventory Model for Plastic Bottles.”
The International Journal of Logistics Management 25 (2): 315–333.
9
Morrow, M. J., and Zarrebini, M. 2019. “Blockchain and the Tokenization of the Individual: Societal
Implications.” Future Internet 11 (10): 220.
Morseletto, P. 2020. “Targets for a Circular Economy.” Resources, Conservation and Recycling 153
(February): 104553.
Nakamoto, S. 2008. “Bitcoin: A Peer-to-Peer Electronic Cash System,” 9.
Nakamura, S., and Kondo, Y. 2002. “Input-Output Analysis of Waste Management.” Journal of Industrial
Ecology 6 (1): 39–63.
Nandi, S., Sarkis, J., Hervani, A. A., and Helms, M. M. 2021. “Redesigning Supply Chains Using
Blockchain-Enabled Circular Economy and COVID-19 Experiences.” Sustainable Production and
Consumption 27 (July): 10–22.
Oliveira, L., Zavolokina, L., Bauer, I., and Schwabe, G. 2018. “To Token or Not to Token: Tools for
Understanding Blockchain Tokens.” In International Conference of Information Systems (ICIS 2018),
San Francisco, USA, 12 Dezember 2018 - 16 Dezember 2018. San Francisco, USA: s.n.
https://aisel.aisnet.org/icis2018/crypto/Presentations/5/.
Oliveira, U. R. de, Espindola, L. S., Silva, I. R. da, Silva, I. N. da, and Rocha, H. M. 2018. “A Systematic
Literature Review on Green Supply Chain Management: Research Implications and Future
Perspectives.” Journal of Cleaner Production 187 (June): 537–561.
Panda, A. K., Singh, R. K., and Mishra, D. K. 2010. “Thermolysis of Waste Plastics to Liquid Fuel: A
Suitable Method for Plastic Waste Management and Manufacture of Value Added Products—A World
Prospective.” Renewable and Sustainable Energy Reviews 14 (1): 233–248.
Provencher, J. F., Bond, A. L., and Mallory, M. L. 2014. “Marine Birds and Plastic Debris in Canada: A
National Synthesis and a Way Forward.” Environmental Reviews, July.
https://cdnsciencepub.com/doi/abs/10.1139/er-2014-0039.
Ragaert, K., Delva, L., and Van Geem, K. 2017. “Mechanical and Chemical Recycling of Solid Plastic
Waste.” Waste Management 69 (November): 24–58.
Ranta, V., Aarikka-Stenroos, L., and Mäkinen, S. J. 2018. “Creating Value in the Circular Economy: A
Structured Multiple-Case Analysis of Business Models.” Journal of Cleaner Production 201
(November): 988–1000.
Reiner, G., Jammernegg, W., and Gold, S. 2014. “Raw Material Procurement with Fluctuating Prices Using
Speculative Inventory under Consideration of Different Contract Types and Transport Modes.”
International Journal of Production Research 52 (22): 6557–6575.
Ritchie, H., and Roser, M. 2018. “Plastic Pollution.” Our World in Data, September.
https://ourworldindata.org/plastic-pollution.
Saberi, S., Kouhizadeh, M., Sarkis, J., and Shen, L. 2019. “Blockchain Technology and Its Relationships
to Sustainable Supply Chain Management.” International Journal of Production Research 57 (7):
2117–2135.
Statista. 2020. “Topic: Plastic Waste in Europe.” Statista. https://www.statista.com/topics/5141/plastic-
waste-in-europe/.
Sudesh, K., and Iwata, T. 2008. “Sustainability of Biobased and Biodegradable Plastics.” CLEAN – Soil,
Air, Water 36 (5–6): 433–442.
Thompson, R. C., Swan, S. H., Moore, C. J., and Saal, F. S. vom. 2009. “Our Plastic Age.” Philosophical
Transactions of the Royal Society B: Biological Sciences 364 (1526): 1973–1976.
United Nations, W., ed. 2015. “Transforming Our World: The 2030 Agenda for Sustainable Development.”
In A New Era in Global Health. New York, NY: Springer Publishing Company.
http://connect.springerpub.com/lookup/doi/10.1891/9780826190123.ap02.
