This filter uses cattle bones and cassava peels to make water safe

Africa is a continent full of frugal inventors – people who see solutions to common problems that also repurpose things others might consider waste. So it is with a filtering device that is providing clean, safe water in remote areas of Uganda where access to water is limited, especially in refugee camps and schools.

Bukere Primary School

Timothy Kayondo is an industrial chemist graduate from Makerere University. As part of his studies, he looked at how quickly the chlorine in Kampala’s public water supply decays between the reservoirs and the taps in residents’ homes. The chlorine, which purifies water, often has dissipated by the time the water arrives at a person’s home. 

So Timothy began working to develop a system that would make sure public facilities like schools and clinics would have clean drinking water. In doing so, he turned to items that others might consider waste – animal bones, cassava peelings, and other waste materials bought from farmers across the country – and solar power, to run the system.

As well as using sustainable, locally sourced materials that otherwise would be discarded, the digitalised portable eco water purification units are affordable by the local population. Once installed, the units are entirely solar powered.

The bones and peelings are cleaned, fired in a vacuum-sealed furnace, soaked in an acidic solution, washed in distilled water, and then crushed into activated carbon. Water is brought to the purifier from tanks or surface water by a solar pump, run through a sand filter, then the carbon filter, and finally through a UV light. 

The Eco Water Purifier, which can purify up to 300 litres of water per hour, fits into an easy-to-carry portable box that is about the size of a large suitcase. An internal battery stores energy from the solar panel. It has been installed in many remote refugee camps and schools and clinics.

Kayondo and his team from Aqua Methods Uganda demonstrated their water purification system at the 2019 conference of the Global Network of Anti-Microbial Resistance and Infection Prevention (Global-NAMRIP) held in Kampala. The group was so impressed that it sponsored the team for the Royal Academy of Engineering’s Africa Prize for Engineering Innovation program, which helps African innovators develop scalable engineering solutions to local challenges.

Last February, Timothy Kayondo was awarded £15,000 from the Royal Academy, following eight months of support he received because he was on the 2020 Africa Prize for Engineering short list. The alumni grant will help him expand distribution to different regions of Uganda, introduce complementary products and reduce the cost of producing the purifier.  


Timothy Kayondo wins Africa Prize 2021 Alumni Grant. University of Southampton, Feb. 9, 2021

Clean water using an Eco Mobile Water Purifier system. University of Southampton.

Making clean water with rubbish. People Fixing the World, BBC, Jan. 18, 2022