Many areas in Kenya are dependent on boreholes for their water supplies. However, this water is often unfit for plants, animals and people when it is too rich in salts or if it contains an excess of natural contaminants that are damaging to health, like fluoride.
Our researchers built a proof-of-concept desalinator for rural households in Lodwar, Turkana (north west Kenya). The device could be made using local skills and readily available components, hence "appropriable" by rural communities. It was tested in December 2018, achieving an initial production rate > 1litre / hour of desalinated water.
We have been developing an affordable and technologically appropriate thermal solar desalination device, easily constructed in Kenya, or other developing countries. It can run without power from the grid, and it can be used by rural households or small communities. We aim to create a Kenyan not-for-profit entity to lead a product development and cost reduction programme to increase yields, optimise the fabrication process and create a market-ready product.
Our current prototype built in Northern Kenya has been a successful proof-of-concept. Work continues through a programme of targeted improvement and optimisation to increase water yields and decrease costs.
Working with a team of collaborators on the ground from different Kenyan research institutes and the Strathmore Energy Research Centre in Nairobi, which have successful experience in engaging with communities, we endeavoured to build and test our prototypes with them. Our priority is that the device is "appropriable" by local communities and businesses in its manufacture, sale and maintenance.
Many Kenyans' nutrition, health, and livelihood depend on scarce freshwater - especially in the arid North, where boreholes supply most of the water - but elsewhere too. This groundwater is often saline, an issue for human consumption, affecting plant growth and livestock health. In addition, a relatively high proportion of boreholes supply water may have excess fluoride beyond the 1.5 ppn (parts per million) limit specified by the World Health Organisation.
In addition, the device has the following distinctive features, which differentiate it from other currently available designs:
- Made using locally available materials or relatively straightforward to procure local labour, technical skills, and entrepreneurship.
- Aims at being economical to build, operate, maintain and repair.
- Relatively "low tech", though it may incorporate reliable, ready-made components which can be cheaply procured.
- Should have at least two operating stages to increase the yield, including two different pressures ("double effect").
- Solar concentration for sterilising water where salinity is not an issue (not requiring evaporation and condensation, just heating the water and holding it at a high temperature for long enough for sterilisation).