Removal of Excess Fluoride from Groundwater Using Natural Coagulant Moringa oleifera Lam and Microfiltration

The consumption of water that has a high level of fluoride can result in dental or skeletal fluorosis, which causes changes in the teeth and bones. Thus, this study aimed to verify the efficiency of the reduction of fluoride in groundwater using coagulation with extracts of Moringa oleifera Lam seeds (MO) combined with microfiltration. Coagulation/flocculation tests were carried out in Jar test with different concentrations of the coagulant and subsequent treatment of water by microfiltration membranes. The concentration of fluoride in water was adjusted to 5mgF(-)/L and pH set to 7.0. The test used 1.5g/L of the coagulant MO, for a 3mgF(-)/L initial concentration of fluoride and pH 3.0 proved effective for the removal of fluoride, colour, and turbidity of water with residual amounts of 1.07mgF(-)/L, 19mgPt-Co/L, and 3 NTU, respectively. The best results were obtained using 5g/L of the coagulant MO and 2 bar pressure in the microfiltration step. Under these conditions, the final water quality complies with the recommendations of the Brazilian legislation, with residual fluoride at 1.2mgF(-)/L, 1.56 NTU turbidity and 8.56mgPt-Co/L colour. These results indicate the potential of the proposed treatment and that this represents an alternative for reducing excessive fluoride from water by combining the use of a natural and biodegradable coagulant with microfiltration processes, which contributes to the final quality of water.