Tamara Štembal

Removal of Arsenic From Drinking Water — Croatian Experience

The groundwater of northern Croatia usually contains high concentrations of iron, manganese, ammonia and arsenic, and is therefore unsuitable for use as drinking water without the appropriate treatment. The existing water treatment plants in this area, applying conventional bio-filtration methods, remove iron, manganese and ammonia efficiently, but arsenic, appearing at concentration levels as high as 300 μg/L, is not removed. Thus, a simple and widely applicable water treatment procedure for the simultaneous removal of arsenic is needed. To find the most suitable water treatment procedure, several technologies employing adsorption, ion-exchange, and membrane processes were tested. A number of laboratory-scale and pilot-plant field experiments were performed on typical groundwater from numerous locations of northern Croatia. The results of the experiments undoubtedly indicate that the simplest and most efficient arsenic removal process from ground water is the adsorption of arsenic on iron(III) hydroxide. Moreover, this process is simply implemented on the existing water treatment facilities, ensuring that the arsenic concentrations in the effluent are as low as γ(As) < 10 μg/L.