Trash to Coin

A blockchain-based system that allows asset-ownership of recycling machines for waste collectors



Blockchain for Social Impact Hackathon

Blockchain for Social Impact Coalition (BSIC) is an initiative of ConsenSys aims to create bridges between NGOs, government agencies, impact investors, philanthropists and technologists by focusing on sectors of Financial Inclusion, Supply Chain, Identity & Vulnerable Populations, and Energy & Environment. In 2017, BSIC held a one-month online hackathon, inviting interested people to participate. Interested in using blockchain to create solutions that address social and environmental challenges, we formed a team of five online. During the one month, we collaborated remotely, researched, ideated, designed, and built a proof-of-concept: T2C – Trash to Coin, a blockchain-based system that allows asset-ownership of recycling machines for waste collectors, ultimately improving their livelihoods and increasing collection of plastic waste on land in order to prevent its leakage into the oceans.



Angela Chen | Domain Expert
Sushmit Sarmah | Software Developer

Yuxi Liu | Interaction Designer
Edson Alcala | Blockchain Enginneer
Arianna Arienzo | Business Analyst

Method & Tool

Interview & Persona
Service Blueprint

Sketch & Framer


September 2017

The Challenge

Ocean Plastic Pollution

The planet’t seas are chocking on trash. It is estimated that there are over 150 million tons of plastic waste in the oceans today, and each year, more than eight million metric tons of plastic waste ends up in the oceans, wreaking havoc on marine wildlife, fisheries and tourism, and causing great damage to marine ecosystems.1

Estimates of business-as-usual scenario show that by 2050, there will be more plastic than fish in the oceans.2 While the usual time horizons for human impacts on climate are forecasted across multiple decades and sometimes centuries, the fact that ocean plastic will overtake fish within our life times catalyzed our curiosity in what solutions may be available to address the looming degradation of marine ecosystems.

Research points out that approximately 80% of ocean plastic waste originates on land, of which 75% comes from uncollected waste. Further, uncollected plastic waste is twice as likely to leak into the ocean.3 On the other hand, land-sourced ocean plastic materials are relatively easy to collect and are one of the better short-term waste leakage solutions.4


Transition to A Circular Economy

Research to date has investigated the concept of ‘circular economy’, which looks beyond the current linear and extractive industrial model of “take-make-dispose” and shifts toward long-term resilience for economic, environmental, and societal benefits. As defined by the Ellen MacArthur Foundation, circular economy “aims to redefine products and services to design waste out, while minimising negative impacts”. 5  

The Ellen MacArthur Foundation has identified 4 essential building blocks of a circular economy: circular economy design, new business models, reverse cycles, enablers and favourable system conditions6 In terms of ocean plastic waste management, reverse logistics provides an opportunity as collecting ocean plastics at the earliest stage offers the best chance at slowing, and possibly reducing the damage. Emerging technologies present power to support the transition to a circular economy. Blockchain, “an open, distributed ledger that can record transactions between two parties in a verifiable and permanent way”, for example, brings the potential of establishing trust and transparency. 7 Within the constraints of this project’s scope, we will explore how to design an interactive system to tackle the issue of ocean plastic pollution through utilizing the blockchain technology.

The Research

Scope and Opportunity

Five rapidly growing countries in Asia – China, the Philippines, Indonesia, Vietnam, and Thailand, contribute as much as 60% of the total plastic waste entering oceans. 8 This finding highlights that a coordinated intervention in these five countries can serve as key leverage in significantly reducing ocean plastic waste. Metro Manila, the most densely populated area in the Philippines, was identified through research as the urban coastal city with the highest visible waste accumulation sites among the polluter countries. 9 We therefore decided to focus on Metro Manila. We surveyed the informal waste ecosystem and learned of the existing cooperatives and nonprofits that work with waste collectors in Manila. We also interviewed experts from the recycled plastic industry and circular economy companies on the dynamics of the reverse logistics value chain for plastics.

Three key themes emerged. First, waste collectors tend to focus on high-value items instead of plastic bottles and bags, which fetch very little from recycling as compared to other materials. Second, waste collectors are stuck in a cycle of poverty with lack of healthcare and housing due to lack of access to the high-value-add part of the recycling chain, namely the processing capability to clean, shred, and grind plastics into pellets. Finally consumers lack easy access to appropriate recycling and have little financial incentive in doing so in the form of rebates.

These problems are in contrast with the market momentum on ocean plastics. Market leadership and convening in the past years show that the global momentum on ocean plastics has already triggered a broad group of stakeholders to act. In particular, consumer facing brands such as Adidas, and Dell are introducing products with new designs, many incorporating recycled plastic and making public commitments on sourcing recycled materials. We identified a unique opportunity to leverage the increasing interest from global brands in recycled plastics with the needs of waste collectors and consumers by creating Trash to Coin. 

The Concept

Trash to Coin

Trash to Coin is a system that has three components. The first component includes a local NGO working with a collective of waste collectors. The NGO registers each collector on the blockchain with a unique ID. The collective receives recycling processing machines from a global brand via a corporate donation and assigns the equity of asset to the waste collectors. Plastic waste is collected and processed through the machines. The NGO provides technical assistance to the group on capacity building, and training of machinery usage. The second component enables the collective to form a forward purchase agreement with a global brand on the processed pellets to be used for products or packaging.  

Trash to Coin offers the global brand traceability and transparency of the sources of the recycled plastic and helps the brand tell its story to consumers. The global brand then distributes the amount earned to the waste collectors via ‘TrashCoin’. In parallel, urban dwellers interface with a mobile application, on which they can earn ‘TrashCoin’ by recycling plastic waste through collection spots distributed in the city. Using the mobile application, urban dwellers can also manage their TrashCoin and make donations to the waste collectors.

Trash to Coin leverages the industry momentum of brands to show market leadership and combine that with blockchain technology to address the two main barriers of plastics collection. Trash to Coin decentralizes the asset-heavy and profitable segment of recycling and giving access to waste collectors. Blockchain builds the trust which allows the asset to be shared amongst the group. Trash to Coin also incentivizes consumers to recycle. Blockchain lowers the cost of tracking this individualized good behavior and rewards consumers accordingly. 


Target User Groups & Personas

As a multilayered system, Trash to Coin interfaces with two main users groups: waste collectors and urban dwellers in Metro Manila.We interviewed local NGO employees to understand the needs of target users. In doing so, we built personas to capture behavior patterns and facilitate empathy.

This helped our team develop and discuss the concept and scenarios of use with a strong user-centered focus.  Their usage of technologies also informed the choice for touchpoints in the concept.

Waste collectors have the need for higher incentives for collecting waste, while different models of contracting sometimes make the ‘market rules’ opaque. They also have a very low smartphone usage. Urban dwellers, on the other hand, have the desire of making positive changes by adapting a green lifestyle, while they lack a convenient way to recycle.

Service Blueprint

A Detailed Walkthrough

From the waste collector’s perspective, we created a service blueprint to examine how different actors in the whole system interact with each other.


Two Main Touchpoints

There are two main digital touchpoints in this system – the mobile application for NGO to help register the collective and request plastic processing machines, and the mobile application for urban dwellers to collect plastic waste and manage their ‘TrashCoin’.


Conclusion & Future Work

The leakage of plastic waste into the ocean has severe consequences for the marine organisms as well as human communities that depend on the marine ecosystem. By examining the model of circular economy, we suggest that a shift toward a reverse supply chain can create economic opportunities and help tackle the issue. In this context, we propose Trash to Coin, a blockchain-based solution that focuses on Metro Manila.

Empowered with blockchain technology, the system allows asset-ownership of recycling machines for waste collectors, ultimately improving their livelihoods and increasing collection of plastic waste on land to reduce its leakage into the ocean.

Although a working demo was made to prove the technical feasibility, Trash to Coin is not yet a fully-functioning prototype. For its future development, Trash to Coin will embark on user evaluation to examine interaction and experience, as well as the choices for interfaces for different touchpoints in a real-life context.

As ocean plastic pollution is a complex global issue, the transition to a circular economy will require coordinated actions from a variety of stakeholders. Therefore, in addition to user and usability testing, another essential aspect of future work is to examine value exchange within the system from a holistic point of view to foster collaboration between different entities. 


  1. Jenna R. Jambeck, Roland Geyer, Chris Wilcox, Theodore R. Siegler, Miriam Perryman, Anthony Andrady, Ramani Narayan, Kara Lavender Law. 2015. Plastic waste inputs from land into the ocean. Science, 347(6233), pp.768-771.
  2. Jennings, S., Melin, F., Blanchard, J., Forster, R., Dulvy, N. and Wilson, R. 2008. Global-scale predictions of community and ecosystem properties from simple ecological theory. Proceedings of the Royal Society B: Biological Sciences, 275(1641), pp.1375-1383.
  3. Oliver Campbell, Adam Bushong, Drew Gartman, Saanya Bhargava. 2017. Identifying sources of ocean plastics: a methodology for supply chains.Retrieved January 23, 2018 from
  4. Ocean Conservancy and McKinsey Center for Business and Environment. Stemming the Tide: Land-based strategies for a plastic-free ocean. 2015. Retrieved January 28, 2018 from
  5. Ellen Macarthur Foundation. Retrieved December 29, 2017 from
  6. Ellen Macarthur Foundation. Building Blocks of a Circular Economy. Retrieved December 16, 2017 from
  7. Harvard Business Review. The Truth About Blockchain. 2017. Retrieved December 12, 2017 from

  8. Oliver Campbell, Adam Bushong, Drew Gartman, Saanya Bhargava. 2017. Identifying sources of ocean plastics: a methodology for supply chains.Retrieved January 23, 2018 from
  9. Philippine Statistics Authority. 2016. Retrieved December 30, 2017 from