Comparative Study of the Quality of Bottled Drinking Water Called Kawthar from some Commercial Treatment Plants in Taiz City, Yemen

Water supply in Taiz city contains high concentration of different elements so it is not suitable for drinking purpose, therefore, the people in the city depend upon commercial water from different units of water treatment. This type of water is commonly called Kawthar. Water quality with regards to pH, Cl₂, HCO₃, hardness, Ca, Mg, NO₃, TS, TASA (total anions of strong acids), coliform group and E. coli was tested. There were variations in some physico-chemical characteristics in the samples but the concentration of these parameters was within the permissible limit of WHO. The reason for this is that all waters used for the treatment were brought from groundwater of good quality from outside the city. Bacterial parameters did not show any growth in coliform group and E. coli and in MPN test show results within the permissible limit, except in K7 and K8 samples. Relation among water quality parameters reveals a significant positive correlation between pH and TASA, TS, SO₄ and hardness. Total hardness shows a positive correlation with TS. SO₄ shows a positive correlation with TASA.