Getachew, Paulos (PhD)Alimaw, Elsabeth2021-03-262023-11-092021-03-262023-11-092021-03-29http://10.90.10.223:4000/handle/123456789/25716With the increased demand and consumption of packed water in Ethiopia especially in major cities like Addis Ababa, there has been a growing concern about the quality and safety of the product. The public used to consider that all packed waters produce are safe. One of the safety concerns is the formation of bromate as disinfection by-products (DBPs) resulting from ozone treatment. Bromate has been identified as a possible human carcinogen and the level in drinking water should be strictly controlled below 10 g/L. As an alternative, UV disinfection produces minimal DBPs. However, this technology also requires high dosage for the effective removal of certain viruses. Therefore, the drawback of conventional disinfectants urges the development of alternative approaches that can improve the robustness of pathogenic removal while avoiding the formation of DBP. Thus, the development of nanotechnology, its application in water and wastewater treatment is becoming increasingly popular. But the microbial safety and quality of water upon this treatment in Ethiopia is not investigated as to our knowledge. Furthermore, in most of the bottled water brands the fluoride level, which is vital for the consumer, is not labeled as well. Therefore, the objective of this study was to investigate the level of bromate, fluoride and microbial load in ozone, ozone+ nano filter and ozone + UV treated packed drinking water brands in Ethiopia. For this purpose, thirty samples representing different brands of packed waters were randomly collected from different supermarkets, kiosks, groceries, cafes and distributer cars. The parameters investigated were bromate, fluoride, pH, Electrical conductivity (EC), Total dissolve solid (TDS), Total hardness (TH), alkalinity, turbidity and microbiological; plate count agar (PCA) and total coliform count. It was found that the concentrations of the bromate were quite different from brand to brand even upon the same treatment and water type. The level of bromate in 8 brand packed water was higher than the permissible limit. The fluoride level except ten (33.3%) brands of packed water all are not mentioned on the label of the bottle (packaged).Therefore 66.6% of the sample has not information about fluoride content. The other parameters ( PH ,Electrical conductivity, total dissolved solid, total hardness, total alkalinity and turbidity) were fulfills the requirement as per the CES and WHO guide lines and at p<0.05.But in some brands the concentrations are far below the requirement and are not recommended for drinking as per WHO standards like PH and total hardness value. All water samples were found free of the microbial contamination.enOzone TreatmentNano FilterBromateFluorideMicrobial LoadThesis