TCD Environmental Engineering Provides Safe Drinking Water in Kenya through Solar Disinfection System

Nov 14, 2008

The first full-scale continuous flow solar disinfection system for a village community has been installed in Ndulyani in the Mutomo area of Kenya to supply safe drinking water for approximately 600 people.

The system has been developed over several years by successive research students under the supervision of Laurence Gill in the Department of Civil, Structural and Environmental Engineering.

The site selection, community liaison and installation of the pilot system were carried out this summer by Colin Price, an MSc student in Civil Engineering, while working for the Irish humanitarian organisation, GOAL as part of a fellowship. GOAL has been working in the most severely drought-affected regions of Kenya since 2006 to improve access to water for over 150,000 people in the region with the construction of dams, hand dug wells and provision of water tanks. The site chosen included the construction of a subsurface dam to store enough of the annual rainfall (which falls in a short rainy season) to supply the community for the rest of the year. The subsurface dam was selected in order to minimise evaporative losses and also provide some degree of protection from pollution.

The water from the dam then flows by gravity into the solar disinfection system. The concept of using solar UV to disinfect water for human consumption is a technology that has been rigorously tested by different research students in TCD’s Environmental Engineering Group and has been proved against a variety of micro-organisms which cause diseases such as dysentery, cholera, typhoid etc. The basic principle of the system involves water flowing through a transparent pipe at the focal point of a compound parabolic reflector, optimally angled beneath the pipe for maximum sunlight capture. The system is designed such that the water flows under gravity, requiring no additional energy source, primarily for use in small-scale rural situations.

Water related diseases account for the majority of premature deaths in sub-Saharan Africa, many of which could be alleviated by the provision of an adequate supply of water for both drinking and washing. In such situations there are often neither the finances nor the resources to construct and maintain the types of water treatment processes used in more industrialised countries which tend to be both energy and chemical intensive, for example, continuous chlorination. Hence, this technology uses solar radiation, an abundant resource in most developing countries, to disinfect water supplies, in place of other disinfection technologies or more commonly where no such disinfection process exists.

The aim of the pilot project is to demonstrate the appropriateness of the technology in terms of the robustness of the system, ease of installation and operation and the acceptance of the system by the local community. In particular, the project will monitor the anticipated improvements to the health of the village community after drinking such solar disinfected water supplies. Future objectives are to collaborate with GOAL to stimulate the start-up of a local company to fabricate these systems, while back in the laboratory in Trinity College, research work is ongoing into enhancing the process by the addition of a fixed photocatalyst.