Africa Center of Excellence for Water Management

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Browsing Africa Center of Excellence for Water Management by Subject "and Batch Experiments"

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    Development of a Point of Use Drinking Water Purifier Using Aluminium Oxide Based Flocculent Disinfectant Composite
    (Addis Ababa University, 2021-07) Namate, Patricia; Zewge, Feleke (PhD)
    The United Nations officially declared access to clean drinking water and sanitation to be a human right in 2010. Despite this, one in every three people in the world still lacks access to clean drinking water. A lot of people suffer from water-borne diseases as a result of contaminated drinking water. Aside from microbiological pollution, high fluoride content in drinking water is one of the most serious problems in African countries. The present study aimed to contribute to the availability of clean water by developing a point of use drinking water purifier using aluminium oxide-based flocculent-disinfectant composite. The study involved the preparation of aluminium oxide (AO) prepared from locally available aluminium sulphate (alum) using a standard method. This was followed by batch experiments to investigate different parameters that affect the efficiency of fluoride removal and E. coli log reduction by the developed method. A dose of 75mg/L AO, 800 mg/L alum, 35% lime and 1.5 mg/L calcium hypochlorite achieved 95% fluoride removal efficiency and 5 log 10 reduction of E. coli using 15 mg/L as initial fluoride concentration and 105 CFU/100 mL E. coli concentration. The optimum contact time was found to be 30 minutes. Initial fluoride concentration affected fluoride removal but showed no effect on E. coli inactivation. The optimum pH of the solution for both fluoride removal and E. coli log reduction was found to be in the range of 4-8. E. coli concentration did not affect fluoride removal. The fluoride removal efficiency and E. coli log reduction were tested on real water samples from the Ethiopian Rift Valley. The results showed that water samples from Rift Valley required a high dose of alum, AO and calcium hypochlorite and a low dose of lime. Three prototypes were developed as high dose, medium dose and low dose for treating water samples with 5 mg/L, 10 mg/L and 15 mg/L fluoride concentrations. The prototypes are powdered form packed in sachets. The high, medium and low doses weigh 11.9 g, 10.6 g and 9.9 g, respectively. The prototypes were tested on real water samples from the Ethiopian Rift Valley and the results were found to be within the drinking water standards. The present study showed that the developed product has the potential to purify drinking water contaminated with fluoride and disease-causing microorganisms. This study suggests that the product should be tested at a pilot scale and upon its success, the product could be manufactured at a larger scale to which communities without access to portable water would use the product for treating drinking water at a household scale.