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Abstract : |
Drinking water, surface and underground water were microbiological and chemical analyzed during storage in covered and uncovered tanks for four months. Microbiological analyses were carried out to determine the microbial indicators namely, Total bacterial counts, total coliform, E.coli, Enterococcus faecalis, Pseudomonas aeruginosa and Clostridium perfringens. Drinking water of Amiria municipal water station was microbiologically safe after storage in covered tanks however, in uncovered tanks the total bacterial counts increased gradually to reach 8 x 102 cfu/ml at the fourth month.With respect to underground water, all tested groups of microorganisms were attained high values except E.coli and E.faecalis counts were not detected. During storage the densities of total bacterial counts, total coliform and P.aeruginosa increased in both covered and uncovered tanks to reach at the fourth month 106-107, 58-68, 51-65 cfu/ml respectively. As to bottled water, samples of four companies producing it in Egypt were taken for analysis during the steps of production. Companies A, B and C were used underground water and company D used surface water. Results revealed that all companies were microbiologically unsastifactory where final product still contained total bacterial counts, P.aeruginosa and C.perfringens exceeding the drinking water quality guideline values. An experiment was conducted to study the efficiency of uv radiation in reducing the densities of certain bacterial isolates inoculated in sterilized tap water. P.aeruginosa was the most sensitive bacteria followed by E.coli whereas E.faecalis and B.cereus were more resistant toward uv radiation., |
