By Kefa Senoga
Uganda Christian University (UCU) has launched one of its latest innovations that will see the institution turn much of its waste into wealth. While launching the waste harvesting and biogas production plant at the UCU main campus in Mukono early September, the Vice Chancellor, Prof. Aaron Mushengyezi, said he had, indeed, come to believe that waste can be gold.
Mushengyezi’s remarks came after watching a demonstration where waste from the UCU kitchen, fecal matter and cow dung is mixed to produce biogas that can be used for cooking. The biogas production plant was a collaborative venture between UCU’s Faculty of Engineering, Design and Technology and PSEM Africa, an engineering company.
Moses Nuwaha, the projects manager at PSEM Africa, highlighted their experience in constructing biogas digesters, with a history of continuous refinement and development. He said even if they have handed over the project to the university, their participation and partnership should continue as they are looking forward to working with the research team to improve the innovation.
Ucha David, the renewable energy engineer at PSEM Africa, who conducted a demonstration of the biogas production, explained that they combine fecal matter, cow dung and food waste to create a diverse feedstock, ensuring a balanced nutrient composition, to be able to generate gas.
Waste is collected from the treatment plant and transported through pipelines to the holding tank. Ucha explained that given that the biogas plant is a prototype, they are currently pumping only one cubic meter of waste per hour, even though the pump has the capacity to handle 20 cubic meters.
According to Ucha, the biogas plant does not only rely on fecal solid and liquid septic waste. They combine cow dung and food waste into the mix to utilize all the resources. He emphasizes that relying only on facal waste would not yield enough gas.
Waste from cooked food is crushed into a homogenous mixture — to the same level like cow dung, Ucha explained. He noted that waste from raw food, such as banana peelings, is not effective for the process.
After obtaining the gas, it is stored in gas bags, which are then transported to the kitchen for use. He adds that a full gas bag of two cubic meters is sufficient for two days of kitchen use.
Dr. Miria Agunyo, the Dean of the Faculty of Engineering, Design and Technology, said their next research will address the packaging of the gas. He said one of the gas bags was accidentally damaged by a stone in the kitchen. In industrial settings, gas is stored and transported in cylinders.
Harry Oryema Langalanga, the chairperson of the Uganda National Biogas Alliance, encouraged the Faculty of Engineering, Design and Technology, which is in charge of the plant, to consider acquiring a solid-liquid separator to enable more efficient utilization of the nutrients found in the digestate. The liquid portion, rich in nutrients, can serve as liquid fertilizer, while the solid part can be subject to further processing or employed as solid fertilizer.
Prof. Elizabeth Balyejusa Kizito, the Director of Research, Partnerships and Innovations at UCU, said her directorate would extend support for the expansion and growth of the project. She appealed to Mushengyezi to consider recruiting more technicians to the different science departments at the university.
Eng. David Kivumbi, the Director of Facilities and Capital Projects at UCU, noted that whatever can be recovered or transformed from waste needs to be harnessed because resources have become limited. He urged the community to engage in research that benefits the community.
Mushengyezi suggested that, perhaps, in future, the university can think of transporting the gas through pipes. He said should the project become more beneficial, the funds previously spent on buying firewood and charcoal could be redirected into supporting the plant.
