Skip to main content

From Waste to Wealth: A Q&A with Agricultural Engineer Noble Banadda

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Editors note: This is part of a series of interviews produced in cooperation with the World Economic Forum with members of its program on Young Scientists, who will be appearing at the Forum’s Annual Meeting of the New Champions in Dalian, China from September 9-to-11. 

The Q&A below features Noble Banadda, Professor of Bio-systems Engineering at Makrere University in Uganda.  

How is your work in wastewater systems improving the lives of ordinary Africans?
For the past 10 years my work has been focused on wastewater treatment—in particular, how to recover resources from wastewater by anaerobically co-digesting waste sludge with food waste to generate energy. For the first part of my work, my focus was on how to optimize the design of reactors. Part of this work involved adapting reactors so that they work in Africa. For example, most automated reactors that use electricity for monitoring and control may not be appropriate for Africa, where power supply can be irregular or non-existent, so we developed a way of using gravity to move it around.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


What is the ultimate goal of your research and how close are you to realizing your ambition?
I’m confident we’ve optimized this process now, so our focus is now on rolling it out. Each reactor serves a community, creating new jobs in maintenance as well as in sorting and grading the waste. We have deployed 25 so far and have a target of 100 by the end of the year, but we need support from business to really reach critical mass.

Sounds like you have a new project in the pipeline …
We’re committed to making the biogas project a success but I’m also very excited about a new project I’ve started developing—pyrolysis. It’s a process that allows us to reverse engineer components from finished products; for example taking a film of polythene or a plastic bottle and restoring it to the biodiesel from which it was created. This has big advantages for the environment, such as biochar that is good for soil remediation and also has the potential to create new jobs. By lowering the cost of fuel, it can make farming more viable, providing an antidote to the mass migration from rural areas to cities that is turning many of Africa’s arable communities into ghost towns. 

What can you tell us about the state of innovation in Africa?
It’s actually very healthy. We are starting to see more home-grown innovation. Mobile technology is often mentioned in this context. A professor recently developed a platform that is able to diagnose malaria based on an SMS picture of a blood sample—in under two minutes. Given that a similar diagnosis can often take up to a week, and that mobile coverage in Africa is almost ubiquitous these days, it’s not hard to see the potential.

In the wider world of science, what area of research do you believe has the greatest potential for improving the world?
In my humble opinion, it’s research into renewable energy that promises to maintain and improve that which was handed to us by past generations. The mass migration we are seeing in Africa today is unprecedented; it is going to put huge strain on urban planning and food production, but most importantly on energy. Science can help us square this circle by converting solid waste into energy.