FLUORIDE CONTAMINATION IN GROUNDWATER AND ITS REMOVAL BY ADSORPTION AND ELECTROCOAGULATION PROCESSES

Endemic fluorosis cases were detected in primary school students in Sarim and Karatas villages situated in the north-west of Sanliurfa. Fluorosis is resulted from high concentrations of fluoride in groundwater and observed in some regions of Turkey having volcanic rocks and geothermal fields. Results of fluoride analyses indicated that the concentrations in groundwater samples were above the admissible limit values for potable water (>1.5 mg L-1). Hence, fluoride concentration in groundwater must be decreased to an optimum level that was recommended in national and international groundwater regulations. Objectives of this work are; to study the high fluoride in groundwater of arid-semiarid region and its health effects on children and to examine its removal efficiency from groundwater by electrocoagulation (EC) and adsorption processes. Adsorption processes were performed by batch method with clay minerals. The fluoride adsorption values concorded well with both Langmuir and Freundlich equations. Low value for K-f (0.14) showed low F adsorption which can be accounted by negatively charged sites on the clay mineral. EC process including the electrodes, reactor and the power source successfully removed the fluoride from groundwater sample. F removal rate was found as 99% at the end of 4.5 h. EC method on the removal of F was more successful than F adsorption on the clay.