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Open Access Publications from the University of California

Scholarly Works (2 results)

  • Thesis
  • Peer Reviewed
UC Berkeley Electronic Theses and Dissertations (2022)

In low-income countries, 93% of waste is burned or dumped while only 2% of waste in high incomecountries is improperly disposed of in this manner. This research focuses on the plastic waste problem in Uganda—a country where 600 tonnes of plastic waste is generated daily and only 6% is collected. Polyethylene terephthalate (PET) is the most prevalent type of plastic waste in Uganda, but it cannot be recycled anywhere in East Africa. Plastic waste in developing countries is a complex, multifaceted problem, and little comprehensive research exists on the subject. Through a technical, social, and business approach, I attempt to present a holistic analysis.

An extended exergy analysis was conducted to quantify the resource use and environmentalimpact of seven different disposal and recycling options for plastic waste that are feasible with Uganda’s limited infrastructure. The results revealed that recycling into a new product is the most resource efficient end-of-life option for PET plastic in Uganda and that transportation can be a major exergy cost. To reduce transportation and keep economic benefits within a community rather than exporting the majority of the profits, a local, circular economy recycling solution was proposed. Additionally, a fundamental phase change heat transfer analysis was used to model the solar drying process many Ugandan recyclers use to dry their plastic after washing.

To demonstrate the feasibility of this proposed distributed recycling model, I co-foundeda social enterprise in Gulu, Uganda. We developed a process and built local machines to transform PET waste into durable, beautiful wall tiles making us the only recyclers of PET in Uganda. Using a community-based approach, emphasizing product-market fit, and pushing the bounds of recommended polymer processing practices, we developed and proved the viability of a solution that did not before exist. This dissertation presents a framework and an example of how to create sustainable solutions for complex technical and social problems that are technically viable, financially sustainable, and embraced by community members.

    Cover page: Analysis of Uganda’s Plastic Waste Challenge from an Exergy, Thermal Phase Change, and Development Perspective to Improve Resource Efficiency and Social Impact
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2024)
    Improved hygiene depends on the accessibility and availability of effective disinfectant solutions. These disinfectant solutions are unavailable to many communities worldwide due to resource limitations, among other constraints. Safe and effective chlorine-based disinfectants can be produced via simple electrolysis of salt water, providing a low-cost and reliable option for on-site, local production of disinfectant solutions to improve sanitation and hygiene. This study reports on a system (herein called "Electro-Clean") that can produce concentrated solutions of hypochlorous acid (HOCl) using readily available, low-cost materials. With just table salt, water, graphite welding rods, and a DC power supply, the Electro-Clean system can safely produce HOCl solutions (~1.5 liters) of up to 0.1% free chlorine (i.e.,1000 ppm) in less than two hours at low potential (5 V DC) and modest current (~5 A). Rigorous testing of free chlorine production and durability of the Electro-Clean system components, described here, has been verified to work in multiple locations around the world, including microbiological tests conducted in India and Mexico to confirm the biocidal efficacy of the Electro-Clean solution as a surface disinfectant. Cost estimates are provided for making HOCl locally with this method in the USA, India, and Mexico. Findings indicate that Electro-Clean is an affordable alternative to off-the-shelf commercial chlorinator systems in terms of first costs (or capital costs), and cost-competitive relative to the unit cost of the disinfectant produced. By minimizing dependence on supply chains and allowing for local production, the Electro-Clean system has the potential to improve public health by addressing the need for disinfectant solutions in resource-constrained communities.
      Cover page: Low-cost, local production of a safe and effective disinfectant for resource-constrained communities
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