Joanne Mac Mahon
Joanne Mac Mahon
Department of Civil, Structural and Environmental Engineering
Supervisor: Dr Laurence Gill
Continuous Flow Solar Disinfection of Drinking Water
According to the United Nations, dirty water kills more people than violence. Current statistics show that 1 billion people still lack access to safe drinking water. About 4 billion cases of diarrhoea each year cause 1.8 million deaths and over 90% of these are in children under 5. In the Millennium Development goals set by the UN General Assembly in 2000, the commitment was made by governments to halve the number of people without access to safe drinking water by 2015.This target is not even close to being reached.
The Civil, Environmental and Structural Engineering Department in Trinity College Dublin has, over the past number of years, designed an appropriate water treatment process which requires little or no energy, uses locally available resources and can be constructed of a low-maintenance durable material. The continuous flow solar disinfection system uses solar radiation, an abundant resource in most developing countries, to disinfect water supplies. UV radiation disinfects water by killing harmful water-borne bacteria and viruses. A pilot-scale solar disinfection system has already been set up in a village in the Katui region of Kenya and serves approximately 500 people. Initial indications in terms of water quality and community acceptance have been positive.
The lab scale UV reactor consists of a series of glass tubes. Behind each tube is a reflector which serves to intensify the UV radiation, heating the water as it runs through the tubing. The idea is that the water is gravity-fed through one end and runs through the reactor at a fixed-flow rate, which ensures that the water receives the required dosage of UV rays. Once the water has passed through the reactor it can be collected at the bottom and is ready for consumption. In the field, this would be a larger system, suitable for village purposes.
• No pumping
• Disinfection guaranteed
• Storage tanks ensure continuous supply
• Low maintenance
In the developing world context there often are neither the finances nor the resources to construct and maintain the kind of water treatment processes used in more industrialised countries, which tend to be both energy and chemical intensive. Chlorination and boiling are widely used but require a continuing supply of chemicals or fuel and a sustainable solution for water disinfection has not yet emerged for a developing world context.
Access to safe drinking water is a basic human right, but at present over a billion people worldwide do not have that access. The Continuous Solar Disinfection System, which has been designed in Trinity College Dublin, can provide a sustainable solution to the water disinfection needs of the developing world and it’s ready to be piloted on a larger scale. A partner is needed to realise the potential of this project. This could be an NGO or an interested organisation which shares the vision of a sustainable water disinfection system for the developing world, which can be manufactured locally, using local resources and which uses the most abundant resources of all in the developing world, which is sunshine.