Estimation of the possible waste reduction by the implementation of SODIS : A numerical-, experimental- and social study executed in Ghana

Sammanfattning: Lack of safe drinking water is one of the biggest humanitarian problems in the world today. Over one billion people in developing countries have no access to good quality drinking water, and subsequently, diarrhoea caused by unclean water leads to 1.8 million deaths of children under the age of five. That corresponds to 90 per cent of all deaths among children in that age group. However, by improving water and sanitation management, one tenth of all worldwide cases of disease can be prevented. In relation to this, the United Nations has launched the seventh millennium goal, which is to half the proportion of people lacking access to safe drinking water by year 2015 (compared with the proportion of year 2000). Therefore, it is important to both improve and develop water treatment techniques in order to achieve a sustainable development, especially in the third world.   Kofi Ansah and Edumafa are two villages on the Ghanaian countryside. Here, as in the rest of Ghana, it is common to drink water from throwaway plastic containers. This is because the water quality is poor in the stationary water sources such as tanks and wells etc. The plastic containers contribute to a big waste problem and it´s therefore desirable to improve the water quality in stationary water sources in order to reduce the waste problem that now is occurring.   Solar Disinfection, or SODIS, is a water treatment technique that is based on solar radiation. Water containers (usually PET bottles) are filled with water and then exposed to the sun for about six hours. The germicidal effect can be derived to thermal heating in combination with the sun’s ultraviolet radiation. The technique is suitable in the third world since the treatment procedure is both simple and inexpensive. The purpose of this study was to estimate the possible waste reduction regarding the small plastic containers by the implementation of SODIS as a water treatment technique, and evaluate if SODIS is an adequate way to improve the quality of water collected from stationary water distribution systems in Ghana.   The study has shown that SODIS is an adequate method for producing low health risk water at a household level in Ghana. A solar exposure of six hours is enough to reach a safe bacterial content within the treated water. It is also clear that SODIS could reduce the present waste problem regarding the throwaway plastic containers by more than 1600 plastic bags per person and year, and that the Ghanaians attitude to start performing SODIS is positive.   Further work should be aimed at implementing SODIS as a water treatment technique by teaching the Ghanaian people, especially in the rural areas, the importance of water and sanitation issues. The implementation of SODIS is a long term project that cannot be accomplished singlehandedly. It can be achieved by instructing certain people in the villages as to how the procedure is done. For this to be effective, these individuals should preferably be well educated and speak both English and the local language. These people can in turn educate and instruct the other villagers in how SODIS is executed and by doing so complete and secure a sustainable use of the technique.