Water quality and business aspects of sachet-vended water in Tamale, Ghana
Author(s)Okioga, Teshamulwa (Teshamulwa Irene)
Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.
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Microbial water quality analyses were conducted on 15 samples of factory-produced sachet water and 15 samples of hand-tied sachet water, sold in Tamale, Ghana. The tests included the membrane filtration (MF) test using mColiBlue24® medium, 3MTM PetrifilmTM test, and Hydrogen Sulfide Presence Absence (P/A H2S) test. With the MF method, 1 factory-produced and 1 hand-tied sachet-water sample had E.coli counts of 5 CFU/100ml and 49 CFU/100ml respectively. Almost half (47%) of the factory-produced sachet-water samples had some total coliforms (range from 1 CFU/100ml to 115 CFU/100ml). All the 15 hand-tied sachet-water samples had total coliforms (range from 4 CFU/100ml to 2010 CFU/100ml). One sample recorded TNTC at a dilution factor of 10. The MF method showed little correlation with the 3MTM PetrifilmTM method (R=0. 16). With the 3MTM PetrifilmTM test method, none of the factory-produced sachet-water samples had E.coli and only one sample had total coliforms with 100 CFU/100ml. The hand-tied sachet-water sample with 49 E.coli CFU/100ml in the MF test, turned out to have 100 CFU/100ml in the 3MTM PetrifilmTM test. The MF test results were considered more reliable.(cont.) For the P/A H2S test, 7% of factory-produced sachet-water samples and 27% of the hand-tied sachet-water samples returned positive results. Overall, hand-tied sachet water was found to be two times more microbially contaminated than factory-produced sachet water. Turbidity tests done on the samples showed that 93% of the hand-tied sachet-water samples and 20% of factory-produced sachet-water samples had turbidities greater than 5 NTU - the limit set by the 1998 Ghana Standards for drinking water. Out of 30 random passer-byes in Tamale and neighboring Savelugu that were interviewed, all drank sachet-vended water, signifying its popularity in the areas. For 37%, sachet water formed the sole supply of drinking water, even at home! 70% drank more water when away from home, 20% the same amount at home and away from home, while 10% drank more water at home. Sachet water formed the main source of water away from home. Sachet-water vendors made 100% to 400% profit.
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2007.Includes bibliographical references (leaves 119-126).
DepartmentMassachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.
Massachusetts Institute of Technology
Civil and Environmental Engineering.