Heavy metal pollution in drinking water and methods of removals

ABSTRACT

Water samples were collected from El-Abbasa Station of Drinking Water, Sharqia Governorate, before and after water treatments. The samples were examined for the presence of heavy metals using atomic absorption spectrophotometer. The effect of slaked lime and activated carbon on the removal of the present heavy metals was studied. The results obtained revealed the presence of cadmium, lead, mercury, copper and zinc in raw surface water [Ismailia Canal] before treatment with an average concentration of 20, 670, 850, 150, and 530 mug/L, respectively. The concentrations of cadmium, lead and mercury in raw surface water were above the permissible limit recommended by USEPA [1979]. After water treatment in El-Abbasa Station the concentrations of cadmium, lead, mercury, copper and zinc in purified drinking water was 10, 480, 540, 130, and 350 mug/L, respectively. Lead, mercury and copper were found in purified drinking water above the levels recommended by WHO [1971]. The reduction% of cadmium, lead, mercury, copper and zinc in raw surface water using slaked lime [300 ppm] was 100.00, 49.25, 48.23, 40.00, and 58.49, respectively, while using activated carbon filter in purified drinking water has a removal% of 100.00, 47.92, 90.74, 84.62, and 7.29, respectively. It can be concluded that slaked lime with alum treatment to raw surface water as well as activated carbon filtration of purified drinking water are effective processes in elimination of heavy metals from water