Turning waste into energy: Our journey in biohydrogen product
Uganda’s capital Kampala, like most cities in Sub-Saharan Africa, is faced with a significant burden of poorly managed waste which is having detrimental effects on public health and the environment. This calls for the development of sustainable solutions.
As civil engineering students particularly interested in public health engineering, we explored options for sustainable management of the organic waste generated from food markets in Kampala.
Food waste at Kalerwe market
Our focus was on Kalerwe market, one of the largest agri-food markets in Kampala, which deals in a wide range of perishable agri-food products, predominantly fruits and vegetables. A survey of five markets in Kampala by the United Nations Environment Program revealed that Kalerwe market had the highest waste generation rates of the five, standing at 7.6kilograms per trader per day. During periods of high harvest, the market is flooded with significantly more supply than demand, resulting in unsold goods going to waste in vast quantities.
Kalerwe, like all the other markets in Uganda, is also faced with the challenge of poor handling and storage of food produce, which worsens the spoilage rate of the produce and increases the waste problem. The organic waste generated at the market has a high moisture content, making it prone to rapid decomposition and releasing bad odours. This attracts scavenging animals and insects that can carry diseases, raising health concerns about food contamination in the market. The vast quantities of waste contribute to the blockage of market roads, the creation of unesthetic conditions and the increased frequency and cost of waste collection for traders.
The poor handling and management of the waste doesn’t stop at the market but extends all the way to the final disposal point: landfill. The waste generated in greater metropolitan Kampala is transported to Kiteezi, a landfill currently operating beyond its capacity. The waste at the landfill is managed through open burning and unsanitary landfilling, posing significant public health and environmental risks. The disposing of this produce means it loses its intrinsic value, when it could still retain its value by being turned into valuable energy resources or nutrient-rich soil amendments.
Turning waste into an opportunity
On the morning of 10 August 2024, a rubbish collapse at the Kiteezi landfill resulted in the death of at least 34 people and the displacement of many homes. This tragic event highlighted the grim consequences of poor waste management and underscored the urgency of finding sustainable solutions. It served as a painful reminder of why our research project is not just an academic exercise but a core need.
By exploring the use of dark fermentation to produce biohydrogen, we aimed to turn the waste burden into an opportunity.
Our research project aimed to turn the enormous quantities of organic waste from food markets in Kampala into hydrogen through a biological process called dark fermentation. This practice makes waste management sustainable as there is already a readily available supply of agri-food waste, and the biohydrogen is produced in an energy-efficient way.
Sample preparation; Elizabeth prepares a slurry of waste for dark fermentation
This project envisioned a wide range of benefits, from giving the market a way to use clean energy for lighting and preserving market products for longer periods, to improved aesthetic conditions in the market, putting less pressure on landfill, and creating employment opportunities for young people and women, which in turn, creates a circular economy.
What we’ve gained from the project
Working on this project has been a transformative experience for us. As civil engineering students passionate about sustainability, we found ourselves at the intersection of waste management and renewable energy production — two areas critical to the future of our cities.
From research to hands-on laboratory work, every step of the project brought new insights and challenges.
We learned to shift our perspective on waste: what once seemed like a by-product to be disposed of has now become a valuable resource.
The realization that the organic waste generated daily in urban markets could be converted into clean energy was empowering. It opened our eyes to the broader implications of our work, not just academically, but in contributing to global solutions for climate change, energy shortages, and sustainable urban development.
Henry purges the reactor bottles to create anaerobic conditions necessary for dark fermentation.
The project also taught us the importance of patience, precision, and interdisciplinary collaboration. Working alongside other researchers and under the guidance of our supervisors, we developed a deeper appreciation for the complexities involved in converting waste into energy. The hands-on experience and field visits to Kalerwe Market offered invaluable practical insights that we will carry with us throughout our careers.
This research project has opened invaluable opportunities for us. Our project was successful in winning the university innovation challenge, organised by the Makerere University School of Engineering. This success meant we were able to represent our university regionally.
We had the privilege of participating in, and emerging winners of, the regional Innovation Challenge under the Higher Education Partnerships for Sub-Saharan Africa (HEPPSA) Programme Review Workshop that was sponsored by the Royal Academy of Engineering. This competition brought together brilliant minds from different universities in the East African region, all focused on addressing real-world challenges through innovation.
Elizabeth and Henry win the regional innovation challenge with their project.
Winning the regional innovation challenge was a thrilling and humbling experience for us. It validated the hard work, creativity, and determination that went into our project. Beyond the recognition, the victory reinforced our belief in the power of engineering and technology to solve pressing societal issues. This achievement also taught us the importance of resilience and adaptability. Throughout the challenge, we had to iterate on our ideas and overcome obstacles, learning valuable lessons along the way. Ultimately, this experience inspired us to continue pushing the boundaries of what’s possible. It showed us that with the right mindset, we can create solutions that drive positive change in our communities and beyond.
Moving forward with our research
As we move forward, we are more committed than ever to pursuing projects that focus on renewable energy and innovative waste management solutions. This project, along with the Innovation Challenge, has reinforced our belief that engineers play a critical role in driving sustainable development. We are excited to continue exploring new ways to integrate sustainability into civil engineering practices and to contribute to a future where waste is not just a problem, but a resource for positive change.
This blog was written by Elizabeth Kisaaka and Henry Amanya, final-year undergraduate civil engineering students at Makerere University, working with Dr Cynthia Okoro-Shekwaga, an academic researcher from the School of Civil Engineering at University of Leeds. Elizabeth and Henry have contributed to her Worldwide Universities Network RDF project: Green hydrogen production from regional resources in Low and Middle-Income Countries.
Read more about Dr Cynthia’s Worldwide Universities Network project: Green hydrogen production from regional resources in Low and Middle-Income Countries