Over the last twenty years, Uganda has experienced an economic boom, placing it among the fastest growing economies in the world. However, an influx of people from rural areas to cities is coupled with a population growth of almost three times the global average, meaning income remains low. Despite its growth, more than 10 million people in Uganda lack access to clean, safe drinking water and water-borne diseases remain the leading cause of death in children under five.

Kathy Ku, an engineering student from Harvard University, visited the country in 2012, and became determined to engineer a solution. Joining forces with fellow student, John Kye, the pair co-founded charity SPOUTS of Water, embarking on their mission to provide safe water for Uganda.

Filtering and disinfecting

Their project, the Purifaaya ceramic filter, is an affordable and easy-to-use water purifier. Made from locally sourced clay, the filters use both physical filtration and chemical disinfection to produce up to two litres of clean water every hour. Tiny holes within the clay allow water molecules to pass through easily, but trap larger harmful particles of dirt and bacteria. A thin layer of silver nitrate acts as a disinfectant to enhance bacteria removal.

To make the Purifaaya system, sawdust and water are added to the clay, forming a thick mixture. This is poured into the mould and pressed to form the pot, before being printed with the SPOUTS logo. The pots are air dried for two weeks before being put into a kiln and fired. The heating process is crucial to harden the pots and turn the clay into ceramic. As the pots are heated, the weak particles of clay flow and fuse together, forming strong bonds between them. The hardened ceramic filtering pots are much tougher than the raw clay and more readily able to cope with the demands of everyday use.

In addition to being made with using traditional methods and locally sourced ingredients, the factories producing the filters employ Ugandan workers, generating jobs and stimulating local economies. The filters themselves give back to the community as well, providing an alternative to felling trees to burn and boil water.

Improving the system

An engineer by training, Kathy is keen to adapt her system as the charity grows, helping her reach her goal of providing all Ugandan citizens with safe, potable water. Seeking a helping hand, Kathy turned to the Royal Academy of Engineering. With the help of Professor Bill Lee FREng, chair in Ceramic Engineering at Imperial College, Kathy was introduced to PhD student, Wirat Lerdprom.

A postgraduate student in the Department of Materials, Wirat visited the rural factory in Seguku earlier this year to lend his expertise. While his current project is looking at ways to reduce processing time when creating porcelains, Wirat used his extensive knowledge of ceramics to improve the production process of the filters. Making an ingenious field lab out of some plastic bottles and poorly-fired filters he had to hand, Wirat was able to look at the composition of the clay in detail. During his time in Uganda, he helped to enhance the preparation of the raw materials, changing the way they were mixed and dried, and even improved the firing efficiency of the ceramics whilst in the kiln.

Since his visit, the factory has increased the production of the water filters by over 30%, resulting in the charity’s best production since opening.

Speaking to Imperial College Kathy said: “Wirat was only able to visit Spouts for five days, but during those days, he was able to help make improvements and find solutions for problems we’d been struggling with for years.”

Image by Marc Hofer [CC BY-SA 3.0-igo], via Wikimedia Commons

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