Microbiological quality of surface water treated with Moringa oleifera seeds or cakes during the storage : case study of water reservoirs of Loumbila, Ziga and Ouaga 3 Dams in Burkina Faso.

Water purification with Moringa oleifera seeds has received a lot of attention because it reduces water turbidity and pathogenic microorganisms. However, it is important to define the optimum conditions of storage to preserve the treated water quality. The study aims to investigate microbial quality of water treated with Moringa oleifera seeds or cake coagulants inrelation to the storage temperature and shelf life in order to define the optimum conditions of storage. A total of 45 water samples from 3 water reservoirs of Loumbila, Ziga and Ouaga 3 dams were collected in sterile glass bottles and treated in triplicate with Moringa oleifera seeds or defatted cakes coagulants. Treated water samples obtained at optimum conditions were stored at room temperature (25°C - 30°C) and at 4°C. Fecal bacteria pollution indicators (Escherichia coli, fecal coliforms and fecal streptococcus) and parasites were monitored every 24 hours during three (3) days abased on laboratory standard methods. Data were analyzed using the Student's t-test and XLSTAT 7.5.2 statiscal software. From the results obtained, bacterial indicators increased significantly with storage temperature (p < 0.0001) and shelf life (p < 0.0001). However, for all water samples bacterial growth was more important in samples treated with Moringa oleifera cakes than seeds (p < 0.0001). For water samples treated with Moringa oleifera seeds and stored at room temperature, bacterial increase after 72 hours was 57 - 80, 42 - 50 and 22 - 47 CFU/100 ml for fecal coliforms, E. coli and fecal streptococcus, respectively. With Moringa oleifera cake's treatment, the increase was 63 - 104, 57 - 82 and 28 - 52 for the same indicators, respectively. Bacterial growth was also more important at room temperature than at 4°C. Thus, microbiological quality of water treated with Moringa oleifera seeds was better than cakes whatever storage temperature and shelf life. Overall, water treated with Moringa oleifera seeds should be stored at low temperature and consumed within 24 hours.