Water quality measures and perception for rainwater harvesting in West Africa
Student thesis: Doctoral Thesis
The approach to rural water supply and management in developing countries is a concern for world organisations and national governments. There is an increasing need for a shift from a centralised infrastructure, which often are not functional to decentralised systems such as rainwater harvesting. With increasing water demand and flood risks, the value of RWH is gaining more recognition worldwide within the academic and policymakers. However, in Nigeria, recognition of RWH as a reliable source of water within government circles is not strong enough to prompt policy statements or actions to promote RWH. Social, technical barriers, as Well as concerns and knowledge gaps exits which impedes government adoption of RWH nationally as a reliable source of drinking water. This research intends to promote large-scale RWH by developing a grading scale to compare risks to human health associated with water from rainwater harvesting and other drinking water sources. The index will grade drinking water sources based on health risk to give a better understanding of the risk associated with each drinking water source. Aiming to encourage policy and investment shift towards rainwater harvesting. Fieldwork was undertaken in a rural community, and drinking water sources were investigated. Microbiological; thermotolerant coliform bacteria and physicochemical; metals, pH, temperature, turbidity parameters of the water sources were assessed. Also, sanitary inspection of the drinking water sources was conducted. The sanitary inspection scores presented RWH systems as having lower sanitary risk scores when compared with scores from the Stream and Well sources. In the perception survey conducted, professional and end-users seem to think that rainwater is a good source of drinking. While the professionals are slightly concerned about water quality, the end-users are ready to make their choice of drinking water source based on appearance, smell, the taste of the water. The microbial and physicochemical tests conducted indicate that the coliform load of water samples from the rainwater tanks were less than that of other sources. However, tanks-2, which has a simple water filter installed at the tank inlet, recorded zero faecal coliform and total coliform if the filter was in place. The physicochemical parameters of the rainwater samples were mostly either below limits of detection or below WHO recommendations and standards, unlike the other sources. Quantitative health risk assessment was carried out using the microbial results leading to the calculation of disability-adjusted life years for each drinking water source. The integration of DALYs, sanitary inspection and perception scores formed the health risk index. The DALYs and the Health Risk Index presents water samples from RWH sources as less contaminated than samples from the Streams and Wells. Policy shift for large-scale rainwater harvesting was suggested and suggestion of further research work to validate the findings of the research were made.
10.5 MB, PDF document