FLUORIDE IN DRINKING WATER: THE PROBLEM AND ITS POSSIBLE SOLUTIONS

Abstract. Removal of fluoride ions from model solutions of Tallinn drinking water was tested using Aqua Juraperle (calcium carbonate) and activated alumina as filtration media. The experiments with Aqua Juraperle demonstrated that this filter medium does not maintain fluoride ions. Other water constituents, except iron, were not influenced by the filtration either. The total iron content was reduced by 50%. Filtration through activated alumina reduced the fluoride concentration in water. The sorption capacity of alumina was 4.5 g/kg and volumetric capacity 3.95 g/L. Different coagulants and their doses were tested to remove fluoride with coagulation as well. The coagulant consumption for fluoride removal was 80 mg Al2(SO4)3 per 1 mg F–. The use of lime milk as a coagulant for water defluoridation is not expedient. Key words: drinking water, fluoride content and removal, filter media, activated alumina, Aqu